Author Topic: CVX-20s info ... (And other Glastrons)  (Read 3081 times)

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Offline cvxjet

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CVX-20s info ... (And other Glastrons)
« on: November 15, 2020, 05:23:13 PM »
Better engine mounts for CVX-20s (And other Glastrons)

Before getting to this subject, I just want to say...If you read this and have either a better idea or something to suggest, please do...I have a bruise on my forehead from slapping it when someone has looked at my "Great ideas" and then suggested something simpler/better- I need to keep that bruise going because it is my signature look!
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When I had my engine rebuilt the first time in 2003, I installed a full-length 10-QT Milodon oil pan because I don't like the front sump Ford pans...They are not so bad in a car (At least an above 13 second car) but in a jet boat you have good-to-great acceleration coupled with some bow rise- this can starve the engine for oil under acceleration.

(Note; I have seen bad reviews for the Milodon pan, but mine fit well and has worked great for 17 years...There are other options, including Canton) I also used the late-model all rubber one-piece gasket- I had to drill out the corner holes for the older larger bolts; Two pieces of 1/4" aluminum plate, drilled for the larger size, plus two holes for clamp bolts- then clamp this fixture (Tightly!) on the gasket to keep the metal bushing INSIDE the gasket from spinning while you drill it out to the larger size)

The problem with a full-length oil pan is that the engine mount set-up for Berkeley Jets has a crossmember that will interfere with the pan. If you only cut it out then this will put more stress on your stringers. I have designed a solution- actually two solutions that really improve the strength of the whole setup.

First up was clearing the pan- that crossmember had to go but I wanted to still have a cross-brace. I picked up a piece of 1/4" steel that would fit between the front and back verticals of the engine mount bracket, then curved it so that it would start at one side, curve under (The oil pan) and then come up the other side (See Diagram). It was not as rigid as the (vertical) original crossmember but better than no cross-brace. After having the piece welded in I cut out the old brace.

This worked for 3 years just fine.....But when I needed the engine rebuilt again (Bad head work when I had a "Friend" port the heads which caused a valve to seize out in the Delta(10 miles home on 1 cylinder bank) I decided to up the ante!

A lot of hot boats are converted to a "Rail mount" engine mounting setup. You bolt a long piece of aluminum angle to the stringers, then cross-members at the front and back of the engine tie together to make a rigid mounting that can handle any amount of power.

But the CVX-20s have a floor on top of the stringers which limit the amount of stringer that is accessible for such a system.....I had to think about this; Gears grinding....smoke out of ears......And a new idea came into being- a Mini-rail system!

I picked up some 1/4" thick angle iron and cut it to fit on TOP of the stringer in that small exposed section, then I used more angle iron to replace the 90* pieces that go between the crossmember and the stringers(Rails) Critical to good strength and rigidity of the setup was that instead of SLOTTED adjustable holes (To fit multiple boats) I drilled the holes in the 90s to exactly fit my engine mount dimensions- so now it is rigid....even if the bolts were a little loose there is no flex or play in the set-up(And no twisting force applied to the stringers).

When I mounted those rails on top of the stringers I mixed up some resin with micro-balloons and cut fibers to make a putty that I put between the top of the stringer and the bottom of the top of the rail- that way the weight load is spread evenly on the stringer (Most of the resin-putty will squeeze out but what's left will even the surface out). I also used the original little plates that were on the bolts thru the stringers; The stringers and fiberglass had taken a set during the manufacturing process so the little plates fit- trying to make it smooth would have taken a lot more work...although it is not particularly pretty, I defy you to find someone who will stand on their head in the engine compartment with a flashlight clenched in their teeth to see those little metal plates!
« Last Edit: November 06, 2023, 07:58:16 PM by Hyperacme »

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #1 on: November 06, 2023, 08:00:45 PM »
Depth-finder GPS Speedo install 

Years ago, I was out in the Delta in late October- checked water temp with a thermometer; 60*...The next week we had a cold snap- but on Thursday I checked an online reading which was at 57* (My waterskiing cutoff was 55* back then(With a wetsuit- I am not a complete idiot)...So Saturday I jumped in the water for my ski ride- and could hardly stand it! Had to keep looking down at the ski to see if it was still there (Could not FEEL it!) When we got to Skye's beach I checked with the thermometer and it was 52*!!!

Because of the silting of the Sacramento Delta, there is more and more chances of finding a sandbar, so I figured I could kill two birds with one...electronic device. Specifically, a Hummingbird 176i. Depth gauge, and also Speedo and water temp readings.

I did not want it (Always) sticking up on the dash of my sleek hot boat, so I mounted it on a hinge so it would fold under the dash- I have some sort of a clip device (Possibly off an aircraft) that holds it tight under the dash, and just use a mini bungee cord to hold it up in readable position...Not completely elegant but it works.

Also, I have compared the speedo function with my original 1977 speedo, and amazingly, that old pitot system is pretty accurate- from 25 mph up to 60 it is right on the button!

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #2 on: November 06, 2023, 08:09:15 PM »
Building a better 460 and Berk jet for our CVX-20 jets

For years and years I have had people tell me that Jet boats suck a bunch of gas- "Your jet uses 2-3 times as much gas as my Malibu Skier!" I kind of had doubts about this right off...One of the most obvious causes of my doubts was that 90% of the ferries in the world use jet drives- Some of this is because of lower maintenance and not having anything hanging down to damage if you hit a reef or beached- but if they really used that much more fuel, no way would 90% of Ferries be jets!
I found a Powerboats magazine test of my CVX-20 that showed it getting 3.2 mpg at 30 mph.....DD Ski boats were getting 3.3-3.5, depending on engine size and boat weight.
I also had been surprised by GM building a pushrod engine after Ford had come out with their DOHC 4V V8 engines...I thought that GM would get their collective butts kicked...And then I started seeing comparisons between 1998 Mustang Cobras and Camaro SS...The Camaro was quicker and got substantially better MPG...What the heck? I thought the 4V engines were the Shizznit!
My 460 took a dump and I needed to get it rebuilt- I talked to a couple of friends who had a machine shop- Wade and Jimmy at "Al Hubbard Marine" in Hayward. They were very cool and did regular engine rebuilds plus all types of more exotic stuff- Sleeving blocks for #s matching restorations, building up hot engines for actual racing cars and boats- They knew what they were doing and did it well.
I found out from numerous sources(Including Wade and Jimmy) that those GM LS V8s had numerous technological advancements- 1) Tight Quench; Quench refers to the flat top of the piston coming close to the flat part of the head- It creates turbulence in the combustion chamber, mixing the fuel/air (And flame front)...Also, the HOT piston transfers some of it's heat to the (Water-cooled) head. All together, this allows leaner mixtures and higher compression ratios. (Four-valve engines cannot make good use of the Quench architecture- There is no room in the combustion chamber because of the four valves)
Also, 2) The cams in the LS are relatively hot, but contrary to old school "Hot" cams, the lobe separation (Degrees of engine crank rotation between the exhaust and intake cam lobes) is wide rather than narrow; Narrow creates a lot of Valve overlap and gives you that rump-rump idle while upping the HP at high "R"s...But the engines would run like pigs below 3000 rpm. By spreading out the lobes (From tight 106-108 degrees to 113-118) you gain a lot of low end power and the engine runs good from idle up to say 5-5500 but you lose approx' 5% off your top end power above 5500. Critically (For this article), the engine will run more efficiently at cruise rpms (2000-3500).
I had Wade "Deck" the block (Machining off the top to make it flush with the piston tops) This made the "Quench" measurement equal to the Head Gasket thickness (.039")...I bought Keith Black Hypereutectic pistons that set the compression at 9:1- that is high for Regular gas (87 octane) but with the good quench it has not been a problem.
Note; I cannot state the right pistons for YOUR build because the 460 heads vary in Combustion Chamber size....Mine were D3VE A2A castings, but even these can vary from 92 cc to 97 cc- You need to have your heads CC'd to make sure. Then buy pistons with the right amount of dish volume to get your comp ratio close to 9:1....(CC the combustion chamber, then; Chamber CC (x) + Piston Dish CC (y) + Head Gasket CC (z) then divide that into your swept volume will give you your Compression Ratio. Mine is x = 92, y = 5, z = 10 for a total of 107 cc = 6.53 ci divided into 58.54 = 8.96:1 compression ratio- (My bore was opened to 4.4" and the stroke is 3.85")

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #3 on: November 06, 2023, 08:11:06 PM »
Page #2

I  had the Heads ported a bit on the exhaust side- They have a port for a smog pump- The Marine engine does not need these ports- they are in a large bump which cuts down on port flow, so simply grinding these down will improve the exhaust port flow.

I had a custom Cam created at Comp Cams (Does not cost any more than a listed cam)....It is a .495/ .510 lift (At the valves) and duration of 219/224 (At .050"lift) and lobe separation of 113 degrees. I used regular lifters and rockers.
Added note; I forgot to mention that the Timing chain setup on our engines in stock form is a retarded "Smog" setup; When rebuilding get a normal "Straight up" timing chain set and that alone will net you approx' 30 hp right off while making the engine run cooler.

As I assembled the engine I decided to use the Weiand Stealth dual plane manifold- Dual planes basically separate the V8 into two 4 cylinders, which improves the fuel-air metering- but the old Dual planes were basically torque intakes- lately, the major companies have been making large-passage dual plane manifolds. Edelbrock has a very good one (Performer RPM) but the Weiand Stealth is both less expensive and actually seems to perform better. (Note; Edelbrock makes a Air Gap manifold which costs a lot more- It does have some benefits in a car, where you get airflow in from the radiator opening to cool the manifold- but in a boat engine compartment there is no airflow to use for under the manifold)

One of the biggest design problems in any of the Ford (Marine) engines is that the oil pan has the sump at the front- this means as a boat accelerates (Accel "G"s plus bow-rise) the oil surges AWAY from the pick-up. So I used a 10 quart pan from Milodon. Instead, you can buy a REAR sump pan- on Amazon it is only $166. Although this is not a Marine pan, the original pans are just stock truck pans- no special treatment.
(Because of my 10 QT pan I had to redesign the engine mount cross-member and ended up making a mini-rail mounting. This should not be necessary if you use the rear sump pan ) Additional note; The rear sump pan probably won't fit- would hit the bottom.

The last detail of the engine build is the Carburetor; I decided to use an Edelbrock 750 Marine Carb. The nice thing about the Edelbrocks is that they are tuned by changing components- not by adjustment screws- With a Holley you usually have to adjust it every so often- I have not adjusted the Edel' after I set it up...That is 14 years of running- basically 1-2 hours for 20 weekends during the summer plus another 20-40 hours during my boat camping trip at Trinity each year....Approx' 6-800 hours of total time. I have changed the fuel filters- both a course plastic filter and a fine metal-matrix filter- a few times tho.

Next up the special tuning of the carb......

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #4 on: November 06, 2023, 08:12:53 PM »
Page # 3

For my CVX-20 Jet boat I set up the Edelbrock carb a little differently than is typical. I leaned the carb out two steps in the midrange; Think about how you usually find out your engine is running lean- You pull hard at a low RPM- say put your car in third at 20 mph and floor it...Then the engine will ping- Pre-ignition, which can damage your engine, so you then richen the mixture.

But a Jet boat is a different; You're at idle, and you hammer the throttle- What does the engine do? It immediately goes straight up to top RPM....You cannot "Lug" a jet boat, ever!

So I leaned it out down low, which gives me much better fuel efficiency at 2500-3500 RPM cruise, and then I richened it up in the top end to make up for any transient lean condition- I also set the accelerator pump at it's highest setting.

Now you may be saying "Sounds good in Theory- but what happens in the long run? Will that lean condition burn the plugs, rings, valves, etc?" Well, I made these changes back in 2003...So I have been running the boat this way for 14 seasons...And just decided to have the carb cleaned, and while that was going on I pulled the plugs and inspected them- They looked great to me, but I decided to back that up with 2 different friends of mine looking them over also- All three of us basically stated"They are fine- almost look brand new" I actually re-installed them. (I had spent some time clocking them back in 2003, so I didn't want to change them if not needed.)

With the cleaned carb, the boat runs like a tiger- the last two years it was a bit hesitant on start-up and actually back-fired a few times. So if you do this set-up, just clean the carb say every TEN years.......

Next up, what I did to the pump.....

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #5 on: November 06, 2023, 08:15:19 PM »
Page # 4

I  decided to rebuild the pump while I had the engine out- being a "JE Insert" pump you have to PULL the engine to pull the shaft out so that you can remove/replace the main bearing. I called around and found Legend jet Drive in Richmond,CA....created by some guys who walked away from Berkeley because the Company was not willing to update the designs at all.

One of the biggest problems with an impeller is, when you build your engine for more HP at higher RPM, you must have the blades on the impeller cut down...But this has a disastrous effect on your mid-range cruise RPM...Basically, the top RPM is set more by the ANGLE of the blades, while the mid-range cruise RPM is set more by the OVERLAP of the blades.

So while the RPM at which the jet absorbs 400 HP moves from say 5000 to 5400 when you cut it down to a "B" cut, the cruise RPM will go from 3200 up to 4000! What the guys at Legend did was to ANGLE the blades at a flatter angle, but then lengthen them substantially....This means that the Impeller "Cut" that absorbs 400 hp at 5000 RPM will now only take 3000 RPM to move the boat at 30 mph (Instead of the 3200 my boat needed for 30 mph with
the original Berkeley "A" impeller).

Sounds good- but Legend Jet Drive was bought out by American Turbine and they told me that they do not make that Impeller....Somehow, I found out that Place Diverter grabbed the Legend designed Impeller and are making it as their own! And they are only charging $380 for them- They are Hard-anodized aluminum....Much nicer looking piece than my 1977-vintage Berkeley impeller.

By the way, you do not have to pull the Jet drive shaft to install a new impeller- Just pull the bowl off and then use a puller to slide the impeller off- then install the new impeller, and torque the nut back down, then reinstall the bowl. (I have included a pic of an impeller in the jet suction housing.
Remove the nut and rent a puller to grab the impeller- it comes off relatively easy- then just make sure the Key is in the shaft when installing the new impeller)

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #6 on: November 06, 2023, 08:16:35 PM »
Page # 5

So here is the final statement on this set up; Originally, the CVX-20 Jet w/320 hp 460 Marine engine would get approx' 3.2 MPG....I saw this number in Powerboats Magazine in a test they did back in 1976. I have seen tests of a number of similar boats- both in Powerboats Magazine and in Trailer Boats magazine- with similar results.

I drove my boat with the new set up from Cedar Stock Marina up to Trinity Center and back- GPS showed 34 miles covered. My new tank is a plastic translucent one- I marked it when I left Cedar Stock, then when I came back from the trip I refilled it to the mark- 9 gallons. (I have actually done this trip twice- once back in 2003 and once in 2017)

34 miles divided by 9 gallons equals 3.78 MPG....That is an 18% improvement, and it beats the direct drive ski boats. You can still get a bit better MPG from a V8 I/O setup.....4-4.5 mpg....They can have the same top speed (60+) but they cannot match the acceleration of the jet (0-30 in 3 seconds vs a typical I/O at 6.5-8 seconds) (I would also add- I did not stay on plane the whole trip- going up I did stay on plane but slowed and idled for approx' 10 minutes at Trinity Center....On the way back down the lake TWICE I had to slow for wake surfing idiots making 4 foot waves- So I plowed along getting around 1.5-2 MPG...If we eliminated all of that my boat may be getting up over 3.9 MPG). I must add that the CVX-20 tested in the February 1976 issue of Powerboat magazine had no windshield- I have a taller-than-stock windshield and actually also had my canvas top up- creating a bit more aerodynamic drag.

To think of this situation in a comparable car type situation; A car getting 32 mpg...make some changes- the car is faster and now gets 38 mpg.

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #7 on: November 06, 2023, 08:18:18 PM »
Page # 6

I  have had some inquiries about cost- I did this back in 2003-6 (most completed in 2004 but getting the carb dialed in took longer (NEVER pump an Edelbrock on cold start! Position the throttle to high idle and kick it over) so, although costs for modifications to a basic rebuild was $800 + Impeller, that cost has gone up- here is a list of parts and costs off of Summit;

Weiand Stealth 8012 manifold; $250.95

Edelbrock Carburetor 1410; $500.95

Keith Black hypereutectic pistons; $450 (Approx'- specific pistons for your build could be a bit higher or lower)

Rear Sump Oil Pan (Actually will not fit (Apparently); $166 on Amazon

Place Diverter Impeller: $380

Camshaft (Custom is not more) $150-160

I was lucky to have a good relationship with my engine builder and also told him to "Take your time over the winter- Don't need it until March" so when he was doing something for another engine, once set up he would also do the same thing on my engine; Cost of labor was $1000...Probably would have been $1300-1400 otherwise. This is not something to run out and do- it is a better way to rebuild your engine when it needs it. I estimate that I have saved approx' 900 gallons of gas since this rebuild (600 Hours @ 30 mph...3.2 MPG vs 3.8 MPG) so, here in CA where gas is approx' $3 gallon(at neighborhood gas stations) over the last 15 years= $2700 saved. And the engine has approx' 400 hp- turns to just under 5000 RPM and the boat hits 62 MPG but is substantially quicker out of the hole; Original 0-30 was 4+ seconds, now it is 3 seconds.

Final note; I forgot to mention that the Timing chain setup on our engines in stock form is a retarded "Smog" setup; When rebuilding get a normal "Straight up" timing chain set and that alone will net you approx' 30 hp right off while making the engine run cooler.


You can just go to the Place Diverter website and look at Products>>Impellers>>Aluminum Impellers,,,,But here is the direct link;

https://www.placediverter.com/home/prod ... impellers/

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #8 on: November 06, 2023, 08:31:05 PM »
Replacing the floor in a CVX-20 Jet

I  bought my CVX-20 Jet in 1999....Immediately took it up to Trinity lake where my family camped every year fro two weeks when I was young....The next year I took my Father out for his 72nd birthday and tried to get him up on his old ski....Sadly, the beach we used to go to back in the 70s was silted up so he couldn't pull off his Step-start.

When I got home I started cleaning the boat, and as I vacuumed the carpet I stepped back to the rear of the floor and it collapsed! I would find out later that the Engine mount cut-outs had a defect that allowed water from Ski lines and anchor lines in those storage areas along-side the engine compartment to leak under the floor.

I checked and the bow area floor was solid, and also the small amount of floor on either side of the engine compartment. It was only the section from the kick-panel back to the beginning of the engine compartment/bilge. I stripped out the interior, pulling the seats, side panels and carpet. The seats were bolted into T-nuts and three of them started spinning....Just pried the seat up then.

Before cutting out the bad floor, I made supports to go between the trailer and the bottom of the hull on each outer side...I even used some old carpet between the supports and the hull. I then put jack stands under the trailer between the hitch and the wheels to help eliminate any sagging while the floor was out.

Then I used a circular saw set at 1/2" depth and started cutting the floor out, which is 1/2" plywood....I would cut a small section and then flex it up and down until it broke loose from the stringers. Watch out for where the floor blends into the hull at the outer edges- If you are not careful you can cut into the fiberglass of the actual hull structure....

After the floor was out I checked the stringers by tapping on them and even drilling into them- Found one bad spot just in front of the bilge and injected some Wood rot hardener into that section.

I sanded the tops of the stringers to get them relatively flat....Then, reasoning that a 23 year old hull might be a little...decrepit, I decided to reinforce the hull. I used some "Baltec" (Now called Coremat) cloth which has micro balloons so is light but really adds thickness, and then some Knytex, which is three different layers of FG cloth woven together....Doing this part was kind of fun; You wet the surface with the catalyzed resin which then drys STICKY (Like a sticky note) and then you take your cloth and...stick it on. After that, you wet the cloth with resin, then stick the next layer of cloth on; You may need to hit the first layer of cloth twice or so to get a good sticky surface for the next layer. The last layer of resin should have some surfacing agent added...basically a wax that floats to the top and then causes the resin to dry hard-non-sticky (And water impervious)

I used the Baltec/Coremat in the valleys between the three stringers, but the Knytex I wrapped all the way across over all three stringers...Note; I did not wet the Knytex on top of the stringers, waiting to do that when the plywood floor was being installed.

I made doublers out of plywood to join the new floor piece to the old floor front and rear, soaking these pieces with resin and installing T-nuts.

I found that Glastron had used 4x8 plywood sheets for the floor, but since the floor needs to be 51 inches wide, they used two sheets....I would need to do the same since the replaced section would be 7 feet long....So I came up with a better idea....

When I pulled the old floor out I had seen that the outer edges had a support strip- just a strip of wood that really didn't even touch the inside of the outer strake where the floor ended...I had planned on carefully measuring a proper piece- but now I decided to go a step further; I bought a couple of 2 x 3s and cut a notch in each for the outer floor edges, while shaping the opposite corner to fit the inside of that outer strake; it has to have the corner rounded lengthwise, and the front end has to taper both in and up to fit the strake...I also angled the lower-inside edges to make a smooth transition for some FG tape to glue on. These mini-stringers then made up the 3 inches(I.5" per side) I needed for the 51 inch wide floor opening. Doing this allowed me to only use ONE 4 x 8 sheet of marine plywood for my replacement floor.

I cut in Clean-out holes under the rear seat, with plastic deck plates to keep water out but allow Checking for water and removal.
Also, I installed T-nuts for mounting the seats- The driver's seat I mounted on a slider to allow adjustment for driver size (But eliminating swivel) and the passenger seat I mounted on a lazy-susan. Both of these seats mounted on top of pressure-treated wood platforms (Note; I recommend using the stock mount for the passenger seat-The lazy-susan doesn't work that well).....All wood was coated with resin.

Once everything was properly fitted, I bonded the two mini-stringers into the outer strakes with epoxy, then taped the inner edges with FG tape and resin.....I had found that the actual floor was curved, with the center slightly lower than the outer edges (Probably for water drainage) So I had my Father come down and stand on the floor when I installed it. I coated the tops of the stringers with resin, and coated the notches in the mini stringers with resin and then a strip of FG tape that I wetted for the floor to stick to. Placed the floor in and had my Dad stand on it while I installed screws in the doublers front and rear, and then wood screws in those outer mini-stringers (Not TOO long!!!!) and longer screws down into the stringers. After my Father climbed out the floor stayed down in the middle.

I let it dry for two days, then taped the outer edges, and finally coated the whole floor with resin and cloth....

Some would doubt my (Partial) floor replacement, and even some of my non-standard procedures...Well, here it is 2020, and the floor is still rock-solid after 19 years of use- and I have been using the boat every year for 20 + weekend river trips (Each year) plus two weeks up at Trinity lake for Most years (The lake was basically empty from 2013 to 2016 because of extreme drought)

Along with all of this, I also moved the kick-panel forward for more leg room- and made it removable.....And the carpet is now held down with the back seat, kick-panel and side pockets (So it is removable for cleaning) I also installed a Mini-Rail engine mount system which protects the stringers from twisting force from the engine's weight.

After all of this, I found water STILL getting in under the floor! I tracked that down to the engine mount cut-outs....They had boxed in the cut-outs for the thru-bolts, but had left small gaps at the bottom....I have another thread that details my filling these holes in...Critically, I filled those holes in back in 2001-2...And since then have not had any water under the floor- even placed a paper towel in there to see if water would soak it at any point; Absolutely nothing!

Fixing the leaky engine mount holes thread; viewtopic.php?f=22&t=11656

Removable kick-panel thread; viewtopic.php?f=20&t=11679

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #9 on: November 06, 2023, 08:36:15 PM »
CVX-20 Reverse Bucket Cable Question

My CVX-20 IMO has never really had good steering. Some of problem is the Reverse Cable is a little short due to the Place Diverter, causing a bind when the jet extends the cable thru the slip Reverse Cable Seal Housing, plus all the cables are original. So I am replacing the Steering and the Reverse Cable. The plan is add a 1 foot the reverse cable to prevent the binding.

Question:
How does one remove the Reverse Cable Seal Housing off the cable? There is a Nylon / Teflon Bushing inside the Housing.
The Seal Housing is sold on the Berkley Site for the JE Pump so I know it has to come off. I can cut the cable and remove it, but how does it install over a new 4300 series cable?

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #10 on: November 06, 2023, 08:43:45 PM »
Making a new (And improved) rear seat for CVX-20s

When I bought my CVX-20 Jet in 1999, it was in bad shape- missing windshield, had been painted and the floor was (Soon) to collapse. The seats were in really bad shape also.

The second year the floor collapsed and while replacing it I bought some Todd plastic-frame seats for up front, but while I mounted the passenger seat to swivel, I wanted the driver seat to slide fore and aft (I did not like it swivelling)

The back seat was going to be a problem; It is VERY specific to the boat (I warn you right here and now- You must measure and be as accurate as possible)

I started by measuring the old seat and where it fit in the boat then drew up a diagram.....A week later I re-measured everything and corrected the diagram. I also wrote up what problems I saw with the original seat;

1) The rear shelf that supports the back edge of the seat bottom was only (Barely) strengthened with a couple of narrow wedges of wood (It was sagging badly)

2) The lower edge of the seat back-board was rotting out- obviously soaked over and over with water.

3) When I removed the seat from the boat the back flexed badly because of the piss-poor design of the ski-pole cut-out

I started cutting the plywood for the seat frame, using templates to get the shapes and sizes right...Then I put the parts together with screws- Stainless screws (No staples at all) This would allow me to take it back apart for adjustments- but actually, I came out pretty close and the seat fit the first time (Amazing! (Hey...!)

To solve the three major problems I came up with 4 fixes;

1) To better support that rear self, I installed FIVE triangular brackets (Made of Plywood) that went from the bottom edge of the seat back to the outer edge of the self- The shelf is SOLID!) (I was worried that the triangular brackets would cause problems for Skis and such in the under-seat storage- Never has been an issue)

2) The lower edge of the seat back; A) I cut that edge approx' 1/2" short and then installed Plastic Furniture glides which keep the seat back above most of the water from Skis, etc- B) I soaked the plywood (Of the whole seat structure) with fiberglass resin- Water simply can NOT get to the wood anymore!

3) The Ski-pole cut-out; Instead of small pieces of 1/2" plywood making a box, I used 1" plywood mounted flat and then 1/2" ply mounted on top, having cut the edges at an angle so anyone digging into the back cushion would not have a sharp (Square) edge to run into- using screws and T-nuts made this rock solid.

I used aluminum angle (2" x 2" x1/8") to go between the seat back and the engine compartment bulkheads, and a 1/4" piece up at the top that takes the stress of the Ski-pole cross-brace, and T-nuts to attach everything to the seat.

The seat bottom cushion was originally tabbed in and fully removable- but later, I modified it so that it has hinges at the front edge and flips up and forward for access to the ski-locker underneath.

Also, I did most of the work starting at the end of summer and continuing thru fall-Winter-spring....in my (Separate) Garage...although I live in (Sunny!) California, the garage would still be down to 40-50 degrees......Resin needs temperatures above 60 to work. I picked up a refrigerator box, then cut one side off completely....I would set the seat on that, then place the box over it...having cut two holes in it- one on each end. I then slid an old hair drier in one hole and pre-heated the wood seat for an hour.

After resining the seat, I would then place the box back over it and heat it for another hour or so.....The resin would cure perfectly!

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #11 on: November 06, 2023, 08:47:41 PM »
Mounting Center rise exhaust manifolds in CVX-20s

Mounting the Center rise manifolds on CVX-20 Jets is difficult- not a lot of room and you have to stand on your head to do it. After a bit of thought (Do I smell smoke?) I came up with a very easy way to mount them.

First, I grabbed a couple of bungee cords and hung them up on the rafter above the engine compartment. Then I used some strong string and made a loop approx' 5 feet in circumference, and looped it thru the exhaust manifold between 1-2 and 3-4 from the outside up on the inside, and then hooked the bungee to it so that the manifold hung just barely laying on the pad over the storage compartment on the side that I was installing the manifold on.

Next, I bought two LONGER bolts same thread/diameter as the mounting bolts, and then cut off the heads, after which I screwed them into the two outer bolt-holes in the head (Of the ones to be used)

Now I was (Basically) ready to actually install the manifold. Step one, I applied some Red high-temp RTV around each exhaust port on the manifold. Step two was taking the manifold and lowering it into the gap between the head/engine and the side of the engine compartment, and then hooking it on those two studs. The bungee then pulled it up against the head. Step three I had to reach under the manifold and install the bolts in the inner holes. Step four was then to remove each stud and replace with the remaining two mounting bolts.

Snug all four bolts slightly but not so tight as to squeeze out the RTV......Wait approx' 20-30 minutes and then snug them a bit tighter so that the manifold takes a proper set against the head. Then wait until 24 hours and at that point torque them properly,

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #12 on: November 06, 2023, 08:51:53 PM »
Making the kick-panel removable

When I first bought my CVX-20 jet, I noticed immediately that it had the Italian exotic car "Simian driving position" (Old italian sports cars all had this) There was very little leg room with the steering wheel way out there.

While replacing the rotted floor (Use those drain plugs in the bilge for under the floor!) I decided to fix this problem. I cut out the old kick panel and made a new one out of 1/2" marine plywood, then had the brilliant idea to BOLT it in so it is removable. So I bought some of those stainless T-nuts and then had to figure out how the MOUNTS were going to go in the boat.

The center wasn't that difficult; I made some plywood brackets that mounted to the runners that hold the fuel tank platform, and then a plywood board ran between them- actually extending beyond them enough to have one bolt per side outboard of the vertical brackets(Plus three in the middle).

But the outer ends of the kickpanel, where it mounts to the hull would be difficult- I made wood blocks that fit the contour of the hull, with a piece of plywood for the bolt to run thru...This took time but I made them fit well, then bonded them to the hull using 2-part epoxy, after which I tabbed them into place with strips of fiberglass.

I installed the T-nuts in the kickpanel, so that the bolts come thru the mounting boards and screw into the kickpanel, then I covered the kickpanel with carpet.

I ended up moving the kickpanel forward approx' 5-6 inches, and, along with making the driver seat a slider rather than a swivel, I now have the seat farther forward, closer to the steering wheel, while I still have leg room- AND I have more room between the driver seat and the back seat.

As far as how solid it is, when I pound on the kick panel (Even 20 years later) it sounds like a piece if plywood glued down to cement...Rock solid! When I first completed this back in 2000, I showed it to my Father (Who had built his own Jetcat in 1961) and he was really impressed.

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #13 on: November 06, 2023, 08:54:07 PM »
Page # 2

Yes, that Simian driving position is just bizarre......I own a Fiero, which is comfortable, but what got me into cars (Originally) was my dentist's Pantera...He probably could have pulled a tooth without novocaine with me looking at that car! But later, I had a chance to buy a Pantera(1984).... after sitting in it I walked away...all of those old Italian mid-engined cars have that set-up...The first mid-engine car with normal seating position was the BMW M1 and then the Fiero and after that the NSX....

I like that your (Bigger) tank is fore-aft rather than cross-wise like mine...I would have done that but didn't want to reposition the filler cap in the deck...

Here are some diagrams of the kick-panel supports....

Offline Hyperacme

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Re: CVX-20s info ... (And other Glastrons)
« Reply #14 on: November 06, 2023, 09:00:23 PM »
Water leaking under floor in Glastrons and Glastron-Carlsons

I bought my 1977 CVX-20 Jet in May 1999.....Started going out with it, enjoying it. Took my Father out on his 72 BD(Sept 2000) to get a Ski ride but a bunch of Jet skiers cut in front just as I was going to hit it (Step-Start) and after he didn't want to try again. When I got home I was cleaning the boat and the floor collapsed under me...
Spent the winter replacing the floor and installing new front seats.....Sealed the marine plywood floor with cloth and resin (Carefully!), and had also installed clean-out holes under the back seat so I could check under the floor for water.
On my Trinity lake trip next June, I checked on the third day- WATER! I had noticed that the engine mount area had what I thought was a manufacturing mistake; The engine mounts are THROUGH-Bolted through the Stringers- Glastron had taken the extra time to BOX the areas in around the cut-out for bolt access- but....
The stringers are not positioned against the vertical wall created by the strakes inside the hull- they are inward approx' 1 inch, leaving a gap, so when they boxed that area in there was a small gap left.....Also, there is a drain hole drilled through the stringer- but it is approx' 1 inch above the mounting point of the stringer, so water can build up and then slip under the flooring. The water is (Mainly) coming from the two storage pockets on either side of the engine bay; Ski lines and anchor lines, plus water from swimmers/Skiers standing on the pads dripping.
When I started the rebuild on my engine, I took a closer look at those gaps, and then decided to do something about them. I bought some FLEXIBLE Isophthalic Resin from the local Tap Plastics, and then mixed in some Micro-balloons (Hollow glass beads- looks like flour) and filled that area, tilting the boat up on each side to give it a surface tilted towards the drain hole. Before doing this I found that Tap also sells pre-made fiberglass tubes in a 1/2" size, so I cut a section and stuck it down there in the groove to allow any water build up (Behind the engine-mount area) to drain forward so it would reach the area under the clean-out holes after circling around the front of the stringers, which stop up under the bow.
Since doing this my under-floor area has remained dry- I even stuck a paper towel in there to see if any moisture ever penetrated- It has been 15-16 years since I did this mod and NO water!

Also, since I have a Berkeley JE-Style jet drive, the pump traps water on the right side at the back of the bilge- the drain plug and bilge pump are on the left side of the jet drive....So I filled the area on the right side with more of the resin and micro-balloons- tilting the boat Bow-up and to the left to create a slope so the water runs over to the pump and drain.

I believe you can purchase the Flexible Isophthalic resin and tubes online....

NOTE/EDIT; Improved the last picture (And no the marbles did not fall out of my ears!)