Alex Hoelzel

also what rod bolts should i run as an upgrade for the 228r and higher rev? arp?

Alex Hoelzel

so i have only one more cam question. i plan on running the 228r and i told my local machine shop dude this. when i went to pick up my heads, he told me about the research he had been doing on my cam. he had found a form that said that the ls1 was running in to 228r valve clearance problems. he printed the form out and handed it to me. he said my pistons may need to be "eye browed". (crap this was supposed to be a low cost build) my question is, has any one heard of such problems with the lm7? i did my own research to find that ls1 pistons are flat top and my 5.3 pistons are obviously not. think i will be ok. i have search for a while but cant find what im looking for. i cant even fine the oem ls1 valve clearance spec or the lm7 oem valve clearance spec. any info on any of this would be much appreciated!

other than that he put the cam in a computerized engine builder. it suppose to be pretty darn accurate. it made :
pk tq: 410
avg tq:341
pk hp: 388
av hp 274
Big LS1 Camshaft questions? - Gen III & IV Chevy V8Z Tech Board - HybridZ

Alex Hoelzel

upon further research the guy who had the valve clearance issues had his heads milled down. so i think im good. but still any info would be appreciated. i plan on going with hardened push rods, any comments on if i need to change the length?

LargeOrangeFont

iTrader: (7)

You'll need to get an adjustable pushrod length checker to see for sure what pushrods you need.

You'll also want to check piston to valve clearance if you are worried about it.

Alex Hoelzel

so i have my push rods sorted to handle the cam. but after looking at the virtula dyno more, my engine drops over 100hp in the last 500 rpm. on another sheet says i am start having moderate lifter pump up at 6000 rpm and severe at 6500 rpm. is that why i am losing so much power the end of the engine pull? how do avoide this lifter pump up? btw i am spinning it up to 6,500rpm. his was with a 112lsa cam but will a cam with 114 lsa fix the power drop off at the last 500 rpm? i know the lsa changes where the power comes on,but does if effect lifer pump up?
thanks

Alex Hoelzel

I talked to him again today, he told me my coil bind is at .050" at .588lift. The threshold for coil bind is .060"-.100" how in the hell do springs (ls1511ml) that max out at .625 lift bind at .588 lift? This makes no sense.

LargeOrangeFont

iTrader: (7)

If you are dropping 100 HP in the last 500 RPM something is wrong. Your lifter preload is probably set incorrectly, and/or your pushrods are too long.

If you have the springs measure the coil bind height yourself in a vise.

What "virtual dyno" are you working with? If you are revving to 6500 you won't need anything exotic to support that RPM.

The coil bind height will change depending on how much you have shimmed the spring seat.

Alex Hoelzel

i am unable to check the coil bind my self at they are already installed into the heads. the specs on the valves say that at 1.8" they have 130lbs seat pressure. with that i should be fine with .588". my coil bind would be more that .100" so i should be fine. the guy who installed them says that i have .050" coil bind at .588 lift. the only way i would have that is if the were installed at 1.738" instead of 1.8". why would he change the install height? that only changes the seat pressure, which has nothing to do with the amount of lift on the cam. why would he want to adjust the seat pressure?

spring specs:
Description: Single
Application: Beehive - LS1 & LS6
Max Life Series Preparation (ML)
O.D.: 1.290in.
I.D. Outer: 0.630in.
I.D. Inner: N/A
Seat Prssure: 130lbs @ 1.800in.
Open Pressure: 370lbs @ 1.175in.
Rate Lbs/In: 384
Retainer Step: 0.000in.
Max Lift: 0.625in.
Coil Bind: 1.100in.