Max compression on pump gas
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Teching In
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Heres my opinion, after tuning for 15+ years, I never had anybody regret going a little lower on compression ratio for safety, and I have had plenty of folks wish they had a bit less compression for various reasons- sometimes it was ambient temp, gearing changes, future FI plans, etc... they all reflect back to your compression because peak cylinder pressure (as was mentioned) is truly the final say, as you can move timing around for a bandaid (like the OEM comptuer does) whereas in a true high performance application you do not want any variable (such as compression) forcing you to back off timing, raising EGT and wasting fuel, because the builder put an extra point of compression into your combination to get 4% or whatever more power.
Off topic here but I got 155,000 miles on this motor. No smoke when started or running. Runs like a champ. Should I overhaul the lower with new bearings and ring's?
I didn't. These bottom ends are pretty incredible. Do your top end and have fun
Thread Starter
Teching In
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How does this setup sound?
Stock lower
.228/.234 cam
New cam retainer plate
243 heads ported and milled .010
Trunion upgrade
7.375 hardened pushrods
Hyd. Lifters W/cross bar
Pac .650 lift springs/ titanium retainers
Stock LS6 Int/TB
New oil pump/timing chain
42# injectors
1 3/4 full length headers
And a good tune.
Am I on the right track here?
Last edited by Black02SLP; Jan 2, 2016 at 08:43 PM. Reason: mill .010
On The Tree
Joined: Dec 2011
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From: Colorado Springs, CO
That sounds like a pretty sweet setup to me. But just to try to save you the headache I went through, buy a pushrod measuring tool and figure out exactly what length pushrod you need before you buy pushrods. Too long or too short will result in bad valve train geometry and that's never good. It will add extra time to your build but will save money if 7.375 isn't exactly what you need.
Thread Starter
Teching In
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That sounds like a pretty sweet setup to me. But just to try to save you the headache I went through, buy a pushrod measuring tool and figure out exactly what length pushrod you need before you buy pushrods. Too long or too short will result in bad valve train geometry and that's never good. It will add extra time to your build but will save money if 7.375 isn't exactly what you need.
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Teching In
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Ya will do. Probly this spring. Its 20 degrees outside now. I will start a new thread cause I'm going to need some help. I will continue doing research on here till then.
I am getting off topic here from the compression title so appreciate all the help.
I am getting off topic here from the compression title so appreciate all the help.
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Teching In
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My comment was for those who say they are at 11.5 on 91 with no issues.
Maybe true if the timing is cut way back. Which sort of defeats the purpose.
Gas these days is junk. 91 the worse. Even worse in the winter.
I agree it's better to go with a little less compression.
On The Tree
Joined: Dec 2011
Posts: 118
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From: Colorado Springs, CO
It's not a bandaid at that point, it's a necessity.
My comment was for those who say they are at 11.5 on 91 with no issues.
Maybe true if the timing is cut way back. Which sort of defeats the purpose.
Gas these days is junk. 91 the worse. Even worse in the winter.
I agree it's better to go with a little less compression.
My comment was for those who say they are at 11.5 on 91 with no issues.
Maybe true if the timing is cut way back. Which sort of defeats the purpose.
Gas these days is junk. 91 the worse. Even worse in the winter.
I agree it's better to go with a little less compression.
Ah some light at the end of the tunnel. Thanks. How does this setup sound? Stock lower .628 228 dur int./.613 234 dur ex. 112+3 cent. New cam retainer plate 243 heads ported and milled .010 Trunion upgrade 7.375 hardened pushrods LS7 lifters and new trays Pac .650 lift springs/ titanium retainers Stock LS6 Int/TB New oil pump/timing chain 42# injectors 1 3/4 full length headers And a good tune. Am I on the right track here?
Also on the timing chain, go with a cloyes 3220. It's a single chain but about twice as thick metal as the stock LS1 chain. It was $38 at oreilly auto last year
Just a suggestion but I see that you're not to far from Livernois Motorsports. They have some great prices on heads and grind there own cams as well. You might want to check them out
Thread Starter
Teching In
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It's a good build plan. That cam is almost identical to mine. It pulls hard and has enough overlap to chop really good. Someone beat me to the pushrods. There is a how to on measuring the pushrods. Get yourself a 12" caliper also for measuring. It will delay assembly about a week but prevent having to go back in for corrective surgery
Also on the timing chain, go with a cloyes 3220. It's a single chain but about twice as thick metal as the stock LS1 chain. It was $38 at oreilly auto last year
Also on the timing chain, go with a cloyes 3220. It's a single chain but about twice as thick metal as the stock LS1 chain. It was $38 at oreilly auto last year
I spent last night researching the pushrod length. If I'm right you take a pushrod tool and adjust it accordingly tighten the rocker finger tight so there is no slop. Then you are looking for 1-1 3/4 turn till you hit 22 ftlbs with torque wrench. Is this right?
Thanks. I have the cam already. Bought it on the forums here. It's custom ground for the 243's ported and milled so I was told. As far as after market heads I can't swing that amount of cash now. Some day I will do a complete build probly with a 6.0 bored and then maybe aftermarket heads like 220's or something like that. I need a bigger piggy bank for that tho. I'm porting the heads myself. I don't know everything about heads but I used to work at Dart porting heads so I should be able to do a decent port job on the 243's.
Teching In
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I measure to 0 lash (just a hair of drag when spinning the pushrod), take that measurement, then add the recommended amount of preload for the lifter I am running.
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Teching In
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0 lash that would be finger tight right? I think I'm going with Comp or Lunati lifters with the bar to get rid of the trays after reading the morel thread on here. The 1 - 1 3/4 turns is not the same on all lifters?
The lifter doesn't affect the bolt rotations to preload calculation. It's the thread pitch on the bolts. If you have a thread pitch of 1.25mm, then one 360 degree rotation is .075" preload. If you have a 1mm thread pitch, one rotation is .062" preload. This is assuming the stock 1.7:1 ratio.
Hope all that helps
Well machined parts very smooth, covered in oil with a spring in the lifter plunger means spin the pushrod is generally terrible advise and results in too tight. Zero lash is when the pushrod wont move vertically between the lifter and rocker anymore, much less chance of error this way.
Thread Starter
Teching In
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zero lash is just barely touching when you tighten the rocker bolt. Read the how to for pictures. Basically, you install the adjustable and you find the length where the rocker just barely doesn't rock with the bolt fully tightened. In other words, if you just barely shorten the pushrod, the rocker had lash with the bolt fully tightened. Then, add your preload to the adjustable, find zero lash on the bolt, and measure your rotations to doublecheck your zero lash measurements.
The lifter doesn't affect the bolt rotations to preload calculation. It's the thread pitch on the bolts. If you have a thread pitch of 1.25mm, then one 360 degree rotation is .075" preload. If you have a 1mm thread pitch, one rotation is .062" preload. This is assuming the stock 1.7:1 ratio.
Hope all that helps
The lifter doesn't affect the bolt rotations to preload calculation. It's the thread pitch on the bolts. If you have a thread pitch of 1.25mm, then one 360 degree rotation is .075" preload. If you have a 1mm thread pitch, one rotation is .062" preload. This is assuming the stock 1.7:1 ratio.
Hope all that helps
Well machined parts very smooth, covered in oil with a spring in the lifter plunger means spin the pushrod is generally terrible advise and results in too tight. Zero lash is when the pushrod wont move vertically between the lifter and rocker anymore, much less chance of error this way.