Hey everyone. Im in the process of building an LQ4. Yes...another one of these thread! I apologize...I know there are alot of these haha. I had a head/cam LS1, and its no longer with us haha. Ill be using lots of parts from the LS1..and also getting some new parts (valve train, cam, etc.).

Im a little stuck. First, Ill list what Im using. What Im looking for is some guidence on head milling and gasket thickness.

- 02 LQ4, stock rotating assembly. All new bearings and rings. ARP rod bolts.

- Older MTI Stage IIe heads. They are 562 casting, ported, bowl work, larger 2.02 intake valves. Chambers are right around 60cc. Yes there are better heads, but I would like to give these a shot.

- Fast 90 intake with Nick Williams TB

- Ported oil pump and some other goodies that probably wont matter to this thread.

Things I need to decide on/buy are cam package, timing set (LS2 HD...ditching my adjustable), LS7 lifters.

Im going to go through PatG for the cam spec and get new springs while Im at it. And eventually order correct pushrods when its together and I can measure.

I did some calculations to see where my SCR would be and here's what I came up with.

Everything as it sits with .051" gasket will give me 10.47:1 with .058 quench.

.041" gasket will give me 10.73:1 and .048 quench.

I did some PTV measurements with checker springs and no gasket. I went 20* BTDC and ATDC and checked at 5* incriments. I wont post those numbers right now, because I dont know if they are needed...or if I should go with a broader range...to 50* or something. So if those numbers will help, let me know and Ill probably go re-check them to be sure.

Obviously I cant use the clay method because I dont have my cam picked out. What Im trying to determine is...do I feed my info to Pat now, get the cam he specs, then do PTV...and if I have room to get thinner gaskets/mill heads, go that way?

Or can I do some more leg work here and determine if I can shave the heads any now, then get my cam spec'd and double check my PTV.

If I drop to 58cc chambers, but have to run .051" gaskets, my quench goes up and keeps my SCR the same. So probably not worth it. But if I can go with 58cc, AND run .041" gaskets, my CR would be 10.99:1 with the .048 quench. Which, from what I understand, would be better.

Any suggestions on where I go from here? Im just swimming with all the info Im reading on cams and timing events and SCR/DCR... Right now the motor is sitting as just a short block. Im held up with these few decisions. I would stick my other cam in to do some clay testing...but its a reverse split cam, and since I wont be using one of those on this build, I dont know if the info it will give is really worth the trouble, or if it will just confuse me more. Im not even sure what bore for the gaskets I should go with. I was using 4.010" in my calcs.

Thanks in advance for anyone that can help...or bothers to read all that crap haha. I was really trying not to post a thread and figure it out but I need some back up. I sent a quick message to Pat...but I know he probably gets 100s of messages, and my questions were kind of a mess. Im a little further along now just banging my head.

J.

Some eye candy in case anyone wants to see.

 

Ok...still racking my brain over this. Probably going to shoot some emails or messages or calls to some builders to try to get some advice but figured I would post once more.

I took some PTV measurements sunday morning. Just to get an idea of my clearances. Again, this was over a span of 40 degrees or so. My measurements BTDC and ATDC were pretty close, but Im only showing one number here. Again Im just trying to get an idea of what kind of shape Im in.

Position Intake Exhaust
TDC .191 .215
5* .201 .226
10* .231 .256
15* .272 .306
20* .333 .366
25* .411 .456
30* .513 .546
35* .621 ---
40* --- ---

This is taking into account a .051" gasket. Anything after 35* pretty much maxed out my checker spring and I couldnt touch the piston.

Does this information even help? Im trying to use cam info and determine whether I have clearance if my cam were to have close to .600" lift..which I dont even know if it will, just using it as a starting point to understand things. If I need to fly cut...so be it. Ill have to do that.

Am I just driving myself crazy here? Spinning my wheels?

J.

 

Still trying to figure some things out! Going to try getting ahold of Pat or someone again also.

 

PM Pat G or call Geoff at EPS. They'll point you in the right direction. You'll definitely have to have some small combustion chambers with those dished pistons IMO

 

Are you against fly cutting? I'd mill your heads, get your cam , and make it all fit.. Your over thinkin it all.. Just get the cam that puts you where you wanna be rpm/power wise , and the rest will fall together..

 

I kind of figured I was over thinking it... I just thought CR #'s were needed for cam selection, and since I was going to make a half a point jump with milling/gasket combo, I was worried it would be premature to get a cam.

Im not AGAINST fly cutting...but Im not sure how much room I have for that with the stock LQ4 dished pistons. Ide rather not have to disassemble everything again, but if thats what it takes, I guess Ide do it.

I know one thing for sure...Ill be getting a tapered piston installer vs. using one of the compression tools. What a PITA that was.

Gonna hit up Pat G or Geoff like you said. I wish there were more guys running 862's with the 6.0 so I could have something to base my build off of. But I realize most guys wouldnt pick em. Im almost thinking about just running the .041 gaskets to get me up to 10.75:1...then do clay testing...THEN mill a little if I can.

Thanks.

J.