Author Topic: Oh-Oh.... crack in head  (Read 361 times)

0 Members and 1 Guest are viewing this topic.

Offline melinprov

  • Sr. Member
  • ****
  • Posts: 191
Oh-Oh.... crack in head
« on: November 30, 2020, 07:23:00 PM »
so I was cleaning up my head tonight so I could put it back on and ran across this crack. It is in the center of the 4 ( aq130c 4 cyl ) and appears to only go across the bridge on top....can I run it? I cant see any cracking below it in the water jacket or on the other side. Not opposed to buying another one but none for sale under $500. right now. I also am thinking-- is this how water got inside?, I still need to build the sea water pump so I don't know what that looks like inside yet but outside looks OK

Offline Plugcheck

  • Donate members
  • Hero Member
  • *****
  • Posts: 2911
Re: Oh-Oh.... crack in head
« Reply #1 on: November 30, 2020, 09:51:07 PM »
Cracks in a head are never good, but since it is not in the combustion chamber area, they may be a little hope.  The exhaust valves are pretty deep, may not stand another valve job.  I don't want to assume the head is aluminum, but your clean areas look shiny like aluminum, if it is, there may be further hope for repair.  Cast iron cracks are tough to fix, but aluminum is possible.   Your best bet, IMHO, is to get it to a reputable machine shop that can give the answers you need.    Maybe there is a Volvo specialty shop that you can call?   I say that because I use a machine shop in So Cal for all my vw air cooled engines(RIMCO). Maybe similar exists for Volvo?
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project
1989 Lowe 200 Redneck fishin Toon
2001 Godfrey Sweetwater pontoon 115 Rude

Offline 185GXSF-Guy

  • Full Member
  • ***
  • Posts: 81
Re: Oh-Oh.... crack in head
« Reply #2 on: December 01, 2020, 07:06:41 AM »
FWIW - Jay Leno has used (and recommended) Lock-And-Stitch for fixing hard-to-find/replace engine blocks if other options fail.  Here's a link to some of his videos : https://engineswapdepot.com/?p=11078

Lock-And-Stitch site : http://www.locknstitch.com/index.html
« Last Edit: December 01, 2020, 07:09:42 AM by 185GXSF-Guy »
2001 GX 185 SF

Offline 75starflight

  • Hero Member
  • *****
  • Posts: 3441
Re: Oh-Oh.... crack in head
« Reply #3 on: December 01, 2020, 08:44:39 AM »
I agree with Mike. Find a good machine shop and see what can be done with it.
1975 v-179 starflite 
1978 CVZ-18

Offline melinprov

  • Sr. Member
  • ****
  • Posts: 191
Re: Oh-Oh.... crack in head
« Reply #4 on: December 03, 2020, 06:20:12 PM »
 well once again living in a small town has its drawbacks sometimes. I do have a good machine-speed shop here that I have used before and the owner has had 4 boats including one 70s boat. Because of the pandemic He had to sell his "hot box" and some other equipment to stay open ( So) He is most capable of fixing it but cant heat it up. I suggested that we build one out of firebricks but he would only pass the cost on to me. Stitching maybe a possibility but its expensive here--about $600.00. I have begun to search for a good used head every night and I am trying to find a farm store that works on tractors/cast iron that maybe able to do it. I have read that Volvo Penta used a alloyed block but can not find what the mix or metal may have been. So far as I know my head is a "special alloyed cast iron " Knowing the mix could help me find a solution if the carbon % is low enough. I did find a great looking head on E bay for only $200. plus 50 shipping and from a 70s aq130c/freshwater only-- but it was bought before I could get it. so Ill keep trying, I have all winter really to figure this out.

Offline carlsoncvx18

  • Donate members
  • Hero Member
  • *****
  • Posts: 1397
Re: Oh-Oh.... crack in head
« Reply #5 on: December 03, 2020, 07:15:34 PM »
I checked on getting a couple of log exhaust manifold that were cracked repaired.

The owner of the shop pretty much told me to buy new aftermarket it will be cheaper than repairing.

1987 CVX18
1977 GT150
1986 CV23
1984 Intimiadator
1981 CV27

Offline Plugcheck

  • Donate members
  • Hero Member
  • *****
  • Posts: 2911
Re: Oh-Oh.... crack in head
« Reply #6 on: December 03, 2020, 09:08:47 PM »
Cast iron is a tough repair, even when special measures are taken, the repair area will never be the same.  Keep an eye out for a replacement.   For small items like exhaust and brackets, heat it up with a torch, stick weld with nickel rod, and bury in dry sand for several hours.   Not sure if that would work on a big item like a block or head, those need an oven
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project
1989 Lowe 200 Redneck fishin Toon
2001 Godfrey Sweetwater pontoon 115 Rude