I know the object of these mods is to up the compression ratio but how much can one expect. I'm gonna be rebuilding my engine soon and am already planning on having the head ported/polished. So I'm thinkin I may just have it milled in the process but I don't want to get my hopes to high for nothin. What difference in compression ratio am I gonna get from taking off 0.010 or 0.020. I'd like to use a thinner head gasket but it seems kinda pointless since the felpro gasket set comes with a head gasket anyway and I've heard they really don't help. Also, what tunning is involved in this? Will I need hotter spark plugs and what about timing? By the way the bottum end will be completely stock and I'm stayin NA. Thanks for any help.
i didnt have a thinner head gasket but i did have a decked head and stainless steel valves in my 97 wayyy back in the day.
car ran great, didnt need tuned to run, although it would have helped a load im sure.
it put down 151whp. stock bottom end, few bolt ons.
Trailer Queen corvette wanna-be with 40 coats of wax and powdercoating that soaks in.
i decked mine .020. No tuning needed, did not need to change the head gasket (and i'd stay away from anything thinner because head gaskets are an issue with the 2.4)
i don't know the exact comp ratio .020 puts out, but its around .2 to .4 (so like 9.6 : 1 would be come 9.8 :1 to 10 : 1)
2.4L reportedly has a .040" quench distance already, you don't want a thinner head gasket.
Also, because it's OHC, there is a limit to how much you can shave before you have to worry about belt tension issues.
fortune cookie say: better a delay than a disaster
GM and many tech manuals inform you not to take no more than .020" off the head or the block....and no more than .020" total.....or you may have time chain issues.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
Since your sticking to stock internals don't worry about raising the compression too much. Seems like your rebuilding it for dependability instead of performance which is good.
Oh and no to the thinner head gasket.
GMR has got nothing on this
Alright so I'm definitly not using the thinner head gasket lol and I'll stick with .020 on the head. Will timing be an issue?
Ethan Duke wrote:Alright so I'm definitly not using the thinner head gasket lol and I'll stick with .020 on the head. Will timing be an issue?
For every .020" the cams move lower on the block the cam timing is retarded 1 degree..
Buildin' n' Boostin for 08' - Alex Richards
Ethan Duke wrote:Alright so I'm definitly not using the thinner head gasket lol and I'll stick with .020 on the head. Will timing be an issue?
i put 15k on my head after being milled .020 ... the timing chain tensioned up normally and the car ran without issue
Brad: is that both intake and exhaust retared?
So I need to advance the timing 1 degree. I'm guessing there aren't any adjustable cam gears available for this engine.
GME Chat User: Speedline02 wrote:Ethan Duke wrote:Alright so I'm definitly not using the thinner head gasket lol and I'll stick with .020 on the head. Will timing be an issue?
i put 15k on my head after being milled .020 ... the timing chain tensioned up normally and the car ran without issue
Brad: is that both intake and exhaust retared?
Both will be retarded because the tensioner will always pull the slack in the chain to one side of the motor...Therefore if you lower the height of the camshafts you make extra slack on both sides of the cams on the chain going to the crank. This will allow the tensioner to move the cams back 1 degree every 0.020"
Buildin' n' Boostin for 08' - Alex Richards
Heres an illustration I did in a thread awhile back.
Buildin' n' Boostin for 08' - Alex Richards
