85.1 944 heads - choices for this engine

[TooManyWrenches]

My 944 saga continues! I found a crack in the head, between the water jacket and the stud jacket in the middle of the head, on the combustion side. Amazing the head isn't warped, but I just checked it with a precision ground parallel and feeler gauge. Block is fine too.
So, what do people do at this point? I can find rebuilt, used, new heads, N/A and Turbo 8v. Is there any upgrade to be made? Will I be fine to buy a used head and bolt it on? Or should I get a new casting, or a rebuilt head?
This is a budget build, but I'm doing it good enough to keep the car for a while. The bearings were trashed from the chocolate milkshake and overheating events, and thee was debris in the pan, but nothing was exploded. Its getting a re-bearing job, and a thorough cleaning and light polishing, but thats about it.

[Evan]

For a budget build, a good used head is your best bet. Just have it checked for cracks and resurfaced by a machine shop before you bolt it on. Avoid mixing N/A and turbo heads as they have different compression ratios. A new casting is overkill for your needs.

[Tom]

I'd probably get a used head on eBay and have a local shop skim it and do a valve job -- but I guess it depends on the condition of the car overall and what you plan to do with it. Always easy for me to spend other people's money....

[rheidtman]

Along with all the other 944 pieces I rebuild, I also rebuild 944 NA, turbo, and S/S2 heads.

Specific to the 944 NA head, I have found they respond well to a simple 3 angle valve job (same as OE), surfacing, valve refinishing, and guide examination. The key is to locate the right core, as many of these I am seeing have considerable pitting and erosion on the mating surface. While it's ok to have this outside the combustion chamber, not so when in the CC and many are now facing this issue. One can certainly have a machine shop weld and repair these areas, but comes at a large expense.

That said, I do have very good condition 944 NA and turbo (many now suffering from ex ceramic failure) cores on hand that I rebuild upon request. I typically do this on an exchange basis to avoid core charges, but do also sell them outright.
I would not suggest bolting up a used head that has not been rebuilt, unless it recently came off a running car. And even then one does not know the history or if the car overheated, which could have trashed the head. Also, many have already been surfaced and may be getting thin, which would necessitate thicker head gaskets...

Feel free to reach out to me if you have any questions...

[rheidtman]

For a budget build, a good used head is your best bet. Just have it checked for cracks and resurfaced by a machine shop before you bolt it on. Avoid mixing N/A and turbo heads as they have different compression ratios. A new casting is overkill for your needs.

just fyi... the combustion chamber CC's on both the turbo and NA head are the same - the compression ratio is managed by differences in the piston top - turbo pistons are dished to reduce CR. The turbo heads use ceramic exhaust runners, stronger valve springs, and sodium-filled ex valves, with all valve sizing being the same at 45 in/40 ex.

So, one could install a turbo head on a NA, but no real benefit... also, as noted, many of the turbo heads are now experiencing ex port ceramic cracks/failures, which could trash the downstream turbo and enter the motor. So, all turbo heads need to be carefully examined before installation.

[zooklm1]

For a budget build, a good used head is your best bet. Just have it checked for cracks and resurfaced by a machine shop before you bolt it on. Avoid mixing N/A and turbo heads as they have different compression ratios. A new casting is overkill for your needs.

just fyi... the combustion chamber CC's on both the turbo and NA head are the same - the compression ratio is managed by differences in the piston top - turbo pistons are dished to reduce CR. The turbo heads use ceramic exhaust runners, stronger valve springs, and sodium-filled ex valves, with all valve sizing being the same at 45 in/40 ex.

So, one could install a turbo head on a NA, but no real benefit... also, as noted, many of the turbo heads are now experiencing ex port ceramic cracks/failures, which could trash the downstream turbo and enter the motor. So, all turbo heads need to be carefully examined before installation.

@rheidtman I have an 86 turbo where the timing belt failed. I have not removed the head yet but am planning to do so in June. I was interested in getting an estimate on the cost for a rebuild assuming that all exhaust valves would need to be replaced. please send me a PM
Thank you,
Lee

[rheidtman]

For a budget build, a good used head is your best bet. Just have it checked for cracks and resurfaced by a machine shop before you bolt it on. Avoid mixing N/A and turbo heads as they have different compression ratios. A new casting is overkill for your needs.

just fyi... the combustion chamber CC's on both the turbo and NA head are the same - the compression ratio is managed by differences in the piston top - turbo pistons are dished to reduce CR. The turbo heads use ceramic exhaust runners, stronger valve springs, and sodium-filled ex valves, with all valve sizing being the same at 45 in/40 ex.

So, one could install a turbo head on a NA, but no real benefit... also, as noted, many of the turbo heads are now experiencing ex port ceramic cracks/failures, which could trash the downstream turbo and enter the motor. So, all turbo heads need to be carefully examined before installation.

@rheidtman I have an 86 turbo where the timing belt failed. I have not removed the head yet but am planning to do so in June. I was interested in getting an estimate on the cost for a rebuild assuming that all exhaust valves would need to be replaced. please send me a PM
Thank you,
Lee

Sure - I did see a PM, but appears to have been removed. Do note the turbo head uses the 'sodium-filled' exhaust valves, which cost a small fortune these days... I've read about aftermarket valves, but no personal experience.
If you are still interested, drop me another PM.

[zooklm1]

@rheidtman I sent a new PM.
Thanks

[Tom]

just fyi... the combustion chamber CC's on both the turbo and NA head are the same - the compression ratio is managed by differences in the piston top - turbo pistons are dished to reduce CR. The turbo heads use ceramic exhaust runners, stronger valve springs, and sodium-filled ex valves, with all valve sizing being the same at 45 in/40 ex.

So, one could install a turbo head on a NA, but no real benefit... also, as noted, many of the turbo heads are now experiencing ex port ceramic cracks/failures, which could trash the downstream turbo and enter the motor. So, all turbo heads need to be carefully examined before installation.

@rheidtman I have an 86 turbo where the timing belt failed. I have not removed the head yet but am planning to do so in June. I was interested in getting an estimate on the cost for a rebuild assuming that all exhaust valves would need to be replaced. please send me a PM
Thank you,
Lee

Sure - I did see a PM, but appears to have been removed. Do note the turbo head uses the 'sodium-filled' exhaust valves, which cost a small fortune these days... I've read about aftermarket valves, but no personal experience.
If you are still interested, drop me another PM.

Removed? Not sure what you were seeing, but I can't think of anyway it could go away unless you deleted by mistake? There's no mechanism/tool for anyone else to remove a pm... (short of hacking the server anyway).

[zooklm1]

I did not realize that a PM stays in the outbox until the receiver opens it. I thought I did something wrong and deleted the message to post my question directly on this thread. I researched this phenomenon and found that what I experienced (PM staying in out box until opened by receiver) was normal. I guess I never noticed it before.
Lee