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cracks between valves. how bad is too bad?

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16K views 10 replies 10 participants last post by  turbo xtc  
#1 ·
i recently removed the engine out of my 89 van 2.5 turbo for a rebuild with 168,000 miles. When i unbolted the head and disassembled it i checked it for cracks. I found cracks between the valves and took it to a engine shop to make sure it was ok. Even though he doesnt know anything about turbo engines(only old school v8s) He told me that those were the kind where the valve seats fall out and he could fix them for about $400 but there was no guarantee it would hold. It didnt seem worth using the head at all since i dont want to take the chance. so i bought a used head off ebay and when i got it i found the same cracks. So i figure they all prolly have them and i would be fine runnin the head. Am i right or would it be too dangerous to assume that? Should i buy a new head or what? help please:confused:
 

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#2 ·
If that crack would cause the seat to fall out, then why aren't people having problems wit hthe heads?
Seriously, just about all of them do it. I don't believe it will be a problem, but if your worried about it, have them fixed.
Both of my heads are the same and they ran ok before pulling the head off. WHen I say ok, I mean no problems with the seat or head itself.
 
#5 · (Edited)
I got a perfect TBI G head that I converted, TBI's don't see as much heat therefore not as much thermal expansion happens....less likely to crack. This doesn't work much for swirl heads though as Gary D says that TBI swirl heads don't have the Tapered Shroud. He says in some cases it increases knock sensitivity. I don't know what the tapered shroud means and I don't care since I run G heads.
I had a seat fall out on a head that wasn't cracked, unless the crack is seriously split open than the head is still useable. I've seen cracks with as much as 1/8'' between them (maybe more, I didn't measure accurately) but at this point it may have been leaking antifreeze into the cylinder.
 
#6 ·
My brand new head from FM cracked within 2000 miles of beatings. Its normal. They ALWAYS do that. Its VERY rare a TD drops a valve seat. Just run the head and dont worry about it. Trust me, and all the others that say the same.

When I brought my head to a local engine shop to get re-surfaced the guy said "this head is junk" I laughed and told him the head had almost $1500 into it and it was on a motor that just made 340WHP. He still said it was "all done" I told him to shut his mouth and I found a new guy to do my work, and this guy is actually very interested in my cars ability to perform.
 
#7 ·
the craks are common and they dont hurt unless they are deep in the head. bu it should be fine my sundance had those and my brother (who runs the napa machen shop) said thats common lol
 
#8 ·
amoparman4ever said:
Even though he doesnt know anything about turbo engines
That's the key sentence in your post.

If I don't see the cracks nowadays I get worried that something is wrong! I've seen the business end of about 8 TD cylinder heads to date.

Somewhere on here you can find a link to a technical service bulletin from Ma' Mopar saying they are a-ok. Leave the crack repairs for the 16v guys.
 
#11 ·
SUPER60omni said:
My brand new head from FM cracked within 2000 miles of beatings. Its normal. They ALWAYS do that. Its VERY rare a TD drops a valve seat. Just run the head and dont worry about it. Trust me, and all the others that say the same.

When I brought my head to a local engine shop to get re-surfaced the guy said "this head is junk" I laughed and told him the head had almost $1500 into it and it was on a motor that just made 340WHP. He still said it was "all done" I told him to shut his mouth and I found a new guy to do my work, and this guy is actually very interested in my cars ability to perform.
the guy at the junk yard told me when i bought my first 2.2 turbo head told my "if it ain't cracked it ain't good" I have bought a lot of heads off him for me and for other people and i have never got one that caused any problems from the stress cracks. put it back on boost some more enjoy!!!