Location: Orlando, FL
Posts: 1,181
My VIN: Former owner of 1098
Club(s): (DCF)
Hello all,
I have my D's heads (and the rest of my engine bits) at a shop right now for measuring & cleaning.
I was just informed that one of them is warped .009 and the other is .008.
My question to you brothers is this:
How much can these heads be machined safely? The engine reconditioning manual does not give this info, it just says
What say you, bretheren?"max warp is .05 over 100mm"
NOTE! Do not level a warped cylinder head, replace it.
Brandon S.
2014 Honda Civic EX
2007 Volvo S60R
Location: CLE/PHX
Posts: 2,592
My VIN: 5646,5080, 5880, 10234, 3639, 2518, 10586, 1538
You can mill up to .040 off the heads safely. We perform clean up cuts all the time ranging from .005 to .015Originally Posted by Morpheus
www.deloreanindustries.com Every Detail Matters
Location: Northern NJ
Posts: 8,581
My VIN: 10757 1st place Concourse 1998
I would try to remove the minimum amount possible. If you have to remove more than around .040 you are affecting all of the geometry and would have to start compensating for the misalignment. You do not have to remove the same amount from both heads. If a head is that warped that you need to remove more than .040 you should be replacing it because it probably won't stay flat anymore.
David Teitelbaum
Location: Orlando, FL
Posts: 1,181
My VIN: Former owner of 1098
Club(s): (DCF)
So, given my circumstances, taking off .010 would be sufficient?
Brandon S.
2014 Honda Civic EX
2007 Volvo S60R
Location: Northern NJ
Posts: 8,581
My VIN: 10757 1st place Concourse 1998
It may be but the machine shop will do their cuts and then recheck for flatness. When you remove metal you remove some stress and create new stress. The heads may warp again and it may require another finer (smaller) cut to finish. Some shops cannot (or will not) remove less than .010 per cut. Depends on their equipment and the operator's skills.
David Teitelbaum
Location: Minnesota
Posts: 1,585
My VIN: 06960
Or you could go the route a few of us have done, and take a whole 1mm off of the heads. Then get Ed's camshafts at DMCEu which are cut with the 1mm timing retard offset in them already for a plug and play high powered operation.
Jim Reeve
DMC6960
D-Status: - Getting some Spring exercise
Location: North GA
Posts: 6,177
Club(s): (SEDOC) (DCUK)
Is the .040 due to head integrity, chain/geometry, or, thicker head gaskets/shims are unavailable? Or? Please elaborate.
Location: CLE/PHX
Posts: 2,592
My VIN: 5646,5080, 5880, 10234, 3639, 2518, 10586, 1538
The camshaft timing is off just a little bit by that point as the tensioner system is over extended on the chains.
www.deloreanindustries.com Every Detail Matters
Location: North GA
Posts: 6,177
Club(s): (SEDOC) (DCUK)
OK, I thought that was probably the case.
So people are actually buying heads instead of getting head gaskets made!?! -- Damn!!!
Location: Northern NJ
Posts: 8,581
My VIN: 10757 1st place Concourse 1998
Milling a lot off the heads will affect valve timing, on one side advancing it and on one side retarding it. You will also have to enlarge the bolt holes in the intake manifold so you can get the bolts in and you will wind up with some port mismatch unless you start porting the heads and/or the manifold. You also increase compression and at some point it will cause you to have to use a higher octane fuel. One way make up for removing a lot of materiel is to use a spacer or you might be able to double up on head gaskets. The factory thought so much of this that their recommendation is that you are not allowed to mill the heads at all! Probably because of the EPA certification.
David Teitelbaum
Posting Permissions
Reply With Quote