Minnesota Classic Glastron Forum
General Category => General Discussion => Topic started by: TylerCV19 on December 20, 2019, 07:38:24 PM
-
Wanted to make a G/C Jet boat thread. Anybody running an overflow dump for pressure concerns or in the stock form is it even unnecessary? Also, thermostats? My jet read off the charts hot this summer (on the gauge) drained and flushed block but can not seem to find the gremlin. Even with a temp gun, nothing really concerned me, manifold elbows ran the warmest around 220 after some WOT passes. Also, anybody have an impeller for a 12JE, I am only getting 57 out of my 460 and there is a cvx 20 I’ve been in that’s running 70 with the same set up I just don’t have the MSD kit.
Cheers, happy holidays.
-
When you flushed the block did you remove the frost plugs? I don't really see any other way to get all the sand out and these jets can suck up a lot.
-
No stock CVX20 runs 70mph.
57mph sounds like a good digit.
-
60 is about top speed on a stock 20 . You don't need the water dump on a stock jet boat.
You should be running in the 145-160 degree range . Do you have the factory tstat system with
the bypass? This is the only system you should use a tstat. If it has valve in the water supply line
off the pump it should be full open . If you are using a tstat try running it without it to test. My
Nephews 23 with a 460 had plugged up at the water inlet lines on the front water pump cover plate
from corrosion . You can pressure test the motor also if you need to rule out a head gasket problem.
-
I promise you this stock cvx 20 is running 70. I will take a video when we summarize it and test drive. I took out the valve to try and rule out a blockage issue. (Dangerous in case of leaks I know) I will definitely check the inlet hoses for corrosion, they seem new but the guy I bought it from was kind of a hack. The thermostat T has never been pulled apart so I’m wondering if there is a foreign thermostat put in place, I appreciate the info. And glad to know I don’t need a pressure relief dump on the stocker set up. I’m running a 750 vac secondary and it’s choking on the top, hopefully it’s just an air intake issue with the dog house that seems to lock everything in.
-
I did not remove the freeze plugs. That is a good idea! Thank you guys, very excited to see you guys this upcoming year with a reliable running CV-19
-
The 460 should operate well with a 750 cfm carb, unless you're pulling above 6500 rpm, which I certainly hope you are not. Might be an issue if airflow around the air cleaner is restricted. I assume by a dump or bypass valve you are considering restricting the water pressure from the pump? Since there commonly is no thermostat in this application, some folks add a valve and calibrate it to temperature results on the engine. My friend Tim's 23 acts like it could use more cooling, not less, so we leave the valve open.
-
Your speed is about right for a CV-19. Mine when new with the 455 Olds ran 58 at 4700 RPM
The 460 has the same horse power and is a little heavier .If you think the engine
cover is cutting off air prop it up some and test it or remove it and see. Mine has only 1/4 in.
between the hatch and top of air cleaner and doesn't cause a problem.
-
Long time ago and can't find pictures .. But Jason removed Brian's engine to replace rusted frost plugs and used some wire to dig out sand that was packed in the block. He had a small plastic kids pool under it to catch water and sand.
There was quite a bit of sand in bottom of pool when he was done.