3.4l iron head valve size question...

[87S10]

A ton. But I would not advise removing more than .010"

Totally agree,you start shaving a lot off and there'll be mis-alignment and sealing problems with the intakes.

[jerome]

well I'm using a 3790 edlbrock cam and have a torquer 2 intake manifold, with a 390 holley, that I'm willing to get milled with the heads I was just looking to bump the compression to some were around 9.5 without stroking or swapping pistons... So would you suggest just boring and stroking the motor to like a 3.2-3.3 what are a good set of piston for these engines anyways. or did any of the other engines come with higher compression pistons that I can grab?

[geoffinbc]

The intake is not the problem. Milling the heads or deck of the block weaken in. If you take too much off then head gasket sealing and warping become a problem. You can take .010 off each and not run into any problems but don't do any more than that.

[jerome]

Not to be to pushy but what is the max you or someone you have know has milled to were they or you have had issues? I would think the issue would be a little bit less of a first approximation like the deck surface of the head, and it thermodynamic properties that these heads have. from the look of them they seem to have a about a half an inch of meat between the deck surface and the water jackets and from what I've herd these heads don't have any cooling issues but that is also with the stock motor. Yeah I was kinda looking at milling 0.05 and doing some porting but I sure don't want to have them warping on me and have other stupid issues that my arise.

[SappySE107]

sonic test for thickness everywhere to see if its even possible. I know the intake manifold will have a problem bolting up with that much taken off but you could mill it as well if the heads would take .050 off and survive.

[blownarrow]

Not to be to pushy but what is the max you or someone you have know has milled to were they or you have had issues? I would think the issue would be a little bit less of a first approximation like the deck surface of the head, and it thermodynamic properties that these heads have. from the look of them they seem to have a about a half an inch of meat between the deck surface and the water jackets and from what I've herd these heads don't have any cooling issues but that is also with the stock motor. Yeah I was kinda looking at milling 0.05 and doing some porting but I sure don't want to have them warping on me and have other stupid issues that my arise.

What's the offset cost of the milling the heads and intake? Have you gotten a price on that? I looked at doing something similar then started weighing the chances of warp, cracking, and lousy workmanship form a shop... I use a shop called Q & E (old race shop from back in the day) but remember good work cost. I opted to go a different root and I'm happy with my choice.. I contacted Venolia and ordered a set of #2642-Dome's for $83.73 per hole..
Any compression you want tailored to you heads and set up... easy-peasy
no decking, warping, cracking, or 18yr old working on your stuff...lol...
http://www.venolia.com/main.html
Just an option

[jerome]

Yeah that is true, my actual goal is to boost the engine and I'm looking for a 3.1 swap but until then I have these nicer, newer, heads and I was just wanting to piss off my engine a little until the time and cash came for the re-fuel injecting and turbo upgrade so I think I will look for a reptetable machine shop and check pricing and who knows maybe a .01 mill with the fiero pistons might be a more logical route to bump the comp ratio, depending on the re ring price... well I'll take that approach for now thanks.

[BillS]

The 3.4 heads are no better and no worse than the 2.8 (later) cast iron heads - they are in fact the same IRRC.

And the same advice for you - if you are going turbo, almost everything you would do for conventional tuning - cam and compression, will be wrong for that. Only the head and manifold work will work for both. You might be better to save the money and do it right all at once when you get around to it.

[jerome]

understand dude im not that big of a douche i know that the static compression ratio for a boosted engine is completely different than that of a NA motor that you are trying to make power out of and unless you got some direct injected heads for this engine I would never run 10-11 to 1 compression on a boosted gas motor unless I had 108 or wanted to have an engine run so shitty that i can barely idle and had almost no timing. especially because of the heat transfer due to the shape of these combustion chambers of the heads at those temps I'm sure detonation is enebtable unless you got some bad octane. I just wanted to spend a couple hundred bucks bump comp. and score some ponys for the time being then when I get some real cash I'll build a motor for boost on a stand and do it right(ring gap, compression, forged pistons, ported heads, matched cam,mega squirt.....) you get the point. and I can refuel inject it with the same set up that i have now minus turbo, turbo tune, and built engine and i would still be nearing my goal while have just a little fun along the way. you don't always have to be so linear.