head swap?
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Registered User
Joined: Jun 2004
Posts: 833
From: Sacramento, CA
head swap?
Hey guys, my Z is down again. I have discovered that my head is warped, and it is allowing water and oil to mix. I caught this pretty early, so no bearings are scored or what not, but I do need to get a new head/get it shimmed. I'd much rather get a new head that isn't warped so that it would be an easier fix, but I can't locate any Z's in Sacramento that have E88 heads on them. What other head could I put on my motor? I want to swap the whole complete head (camshaft, cam gear, valves, etc), so I need something compatible with my stock Z block (p30 I believe).
Registered User
Joined: Mar 2005
Posts: 474
From: Boulder, CO
A long time ago I tried a milling option to fix a warped head and it could be done, but it was kind of a pain (getting exactly the right new headgasket thickness and/or cam tower adjustments, etc., etc.). But, it does work. Or maybe try zparts.com or zcarsource.com and see what shipping one to you might cost, just to compare money to effort and see what your preference is.
good luck,
Dave
good luck,
Dave
Registered User
Joined: Nov 2004
Posts: 14
From: Reno,NV
go to http://zccw.org/Tech/Engine/Combo.html to check out head-block combinations
Registered User
Joined: Dec 2000
Posts: 74
From: Cashmere, WA 98815
You can have your head resurfaced. And run a stock or thicker head gasket, depending on what your engine compression is, or has been. Usually, 30 - 60 thousands off a head will straighted it for you on a Datsun head. If you go more than 60 thousands, start checking for valve & piston interference. You may then wish to explore the use of a thicker head gasket.
The head thickness, if surfaced will move the cam closer to the crank. Usually on the Datsuns, there are three alignment holes in the cam chain sprocket, usually marked 1,2,3. These were orginally installed to take slack out of the timing chain as it streached. I think its something like 4 - 6 degrees change between each position. With a stock chain, you may be able to set the cam sprocket in position #2 or #3, to tighten up the chain without needing to worry about shimming. And if your running a wild cam, you could always buy an aftermarket adjustable cam sprocket and set your cam and chain where ever you want it.
Speed
The head thickness, if surfaced will move the cam closer to the crank. Usually on the Datsuns, there are three alignment holes in the cam chain sprocket, usually marked 1,2,3. These were orginally installed to take slack out of the timing chain as it streached. I think its something like 4 - 6 degrees change between each position. With a stock chain, you may be able to set the cam sprocket in position #2 or #3, to tighten up the chain without needing to worry about shimming. And if your running a wild cam, you could always buy an aftermarket adjustable cam sprocket and set your cam and chain where ever you want it.
Speed
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Fast240, depending on how bad the warpage is, heads can be re-straighted. This is done on a straightening plate and a Big Hot **** Oven. It's heated, torque / re-torqued, reheated. The allowed to kewl slowly, and this might be done in stages as not to shock the head or put added stress into the casting.
Now for surfacing the head to being flat, the only way to do it rite, is to mill it "fly cut it." No belting of heads is recommended this is a dated practice. That with unskilled hands, or somebody making haste, will more than likely lead to a boat anchor. So don't let any body, talk you into it other wise.
And before you spend a fist full of cash, have the machine shop pressure check it. Prob. in the 20-35 dollar range. This will revile cracks at that point. if the shop does not have a pressure tank just take it somewhere else.
If all that is needed to straighten the head is.015--.025 you shouldn't have any clearance Probs. there should be more than enough margin, in valve and squish clearance. But it is always safe to clay a coulple holes and see. Because the previous owners might have had some work done in the same manor, so be safe.
I hope this helps drop me line if you need anything
Scott
Now for surfacing the head to being flat, the only way to do it rite, is to mill it "fly cut it." No belting of heads is recommended this is a dated practice. That with unskilled hands, or somebody making haste, will more than likely lead to a boat anchor. So don't let any body, talk you into it other wise.
And before you spend a fist full of cash, have the machine shop pressure check it. Prob. in the 20-35 dollar range. This will revile cracks at that point. if the shop does not have a pressure tank just take it somewhere else.
If all that is needed to straighten the head is.015--.025 you shouldn't have any clearance Probs. there should be more than enough margin, in valve and squish clearance. But it is always safe to clay a coulple holes and see. Because the previous owners might have had some work done in the same manor, so be safe.
I hope this helps drop me line if you need anything
Scott
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