15 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHCylinder Head resurfacing
Leading reported evidence
Check of the head's surface
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
My training in this area had me avoiding removing any metal unless it was clearly called for -- proper checking of the head's surface using a precision surface plate and the appropriate tools was required to thoroughly characterize the surface topology/geometry of the head -- and then removing only the tiniest amount of material needed to bring the head to spec.
Leading evidence: 'Check of the head's surface' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check of the head's surface' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
I have to figure porsche should have the same sort of trick since changing the compression ratio is easy to do with the gasket.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
Too often though shops will just set the depth of cut to 0.010" or whatever and take a cut.
Use precision surface plate and the appropriate tools was required
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
My training in this area had me avoiding removing any metal unless it was clearly called for -- proper checking of the head's surface using a precision surface plate and the appropriate tools was required to thoroughly characterize the surface topology/geometry of the head -- and then removing only the tiniest amount of material needed to bring the head to spec.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Check of the head's surface
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
My training in this area had me avoiding removing any metal unless it was clearly called for -- proper checking of the head's surface using a precision surface plate and the appropriate tools was required to thoroughly characterize the surface topology/geometry of the head -- and then removing only the tiniest amount of material needed to bring the head to spec.
Use precision surface plate and the appropriate tools was required
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
My training in this area had me avoiding removing any metal unless it was clearly called for -- proper checking of the head's surface using a precision surface plate and the appropriate tools was required to thoroughly characterize the surface topology/geometry of the head -- and then removing only the tiniest amount of material needed to bring the head to spec.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
15 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261027T035758Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
I am sending my 1-3 cylinder head to Costa Mesa R&D for repair to the #1 cylinder crack and was wondering what the maximum amount of material to take off the head as far as resurfacing goes? Without getting close to valve to piston contact and also to keep compression around 11.3 to11.7:1.
Heads must be decked perfectly even to maintain combustion balance. if you aren't pulling both heads and machining them equally, don't deck the cylinder head at all.
I should clarify my post: it's just one head that needs to be repaired but both heads will be resurfaced (decked); the engine has been pulled and the short block sits on an engine stand. Thanks for the reply.
I should clarify my post: it's just one head that needs to be repaired but both heads will be resurfaced (decked); the engine has been pulled and the short block sits on an engine stand. Thanks for the reply.
I don't know an answer but can add that possibly there are different head gaskets thicknesses you could use. It's common to have different gasket thicknesses for performance bike engines. I have to figure porsche should have the same sort of trick since changing the compression ratio is easy to do with the gasket. When going to a turbo and such thicker gaskets lower the compression to the desired value. So pretty much if shaving the heads is required then a thicker gasket can save you from too close of a tolerence.
When Costa Mesa R&D repaired my cylinder head 1-3 they did not resurface the deck (I only sent the one head). Why are you having it resurfaced? Are there flaws or damage?
Outstanding.. Had me really worried there.
There are no multiple thickness gaskets available for the M96 engine due to the MLS construction of the gaskets.
The shop doing the work should be able to advise the material removal.. We have our own parameters as their is no rule book concerning this aspect of the engine.
Found this in the workshop manual regarding head resurfacing, for what it's worth.
permissable surface uneavenness = 0.002"
permissable unevenness after machining = 0.001"
minimum head depth (wear dimension) = 5.5767"
while machining, peak to valley height = 0.0006"
Costa Mesa R&D knows where the limits are. They've done many M96 heads for multiple So Cal performance shops....
Curious, what's their lead time right now?....
It's a good idea to resurface, according to Steve Baker at Baker Cylinder Heads in Henderson, NV. It provides assurance the head is completely flat for sealing correctly due to heating and cooling of the aluminum.
pretty horrible way to mess with compression. You can lower compression with a thick headgasket and actually be more prone to detonation due to the changes in the quench.
With this thinking then it also makes sense to resurface the block surface against which the head fits.
My training in this area had me avoiding removing any metal unless it was clearly called for -- proper checking of the head's surface using a precision surface plate and the appropriate tools was required to thoroughly characterize the surface topology/geometry of the head -- and then removing only the tiniest amount of material needed to bring the head to spec.
Too often though shops will just set the depth of cut to 0.010" or whatever and take a cut.
This affects the compression ratio a bit but it also in the case of these engines affects the IMS to cam shaft chain play. The tension can of course compensate for this but the less metal removed the better off the engine will be.
Sincerely,
Macster.
