[Nabush]

Hi,

I'm finishing my 2nd cam on my LT1...

This time bought Morel 4708 Performance lifters ($$) with 0.120" plunger travel. I was going for Johnson 2110 but absolutely impossible to find right now because of COVID. Those Morel should be good though, but they costed me more than 50% more than the Johnson...

My previous lifters were Morel 6504. With 7.850 pushrods my preload was 0.075 (they are 0.200 travel)

Now with the 4708 and the 7.850 pushrods my preload is 0.093 which is too much for 0.120 plunger travel (Morel recommends 0.045-0.050)

Question is : 7.800 pushrods will put it on the low side (0.043), 7.825 will still be too high (0.068)...

What would you take between 7.800 and 7.825 ? Better on the low side or on the high side ? Personnaly I'm leaning towards the 7.800....

Also just to confirm the usual rule 1 turn = 0.050 is wrong. It is 0.050 at the bolt, but on the pushrod it is 0.075 because of the rocker ratio (confirmed with a dial indicator). Just wanted to put that here

Thanks

[KingLT1]

Are you factoring expansion into your cold measurement? once up to temp you will see around .013 of expansion so you will lose some pre-load compared to a cold measurement. So if those are cold measurements then the 7.825 should be ok at operating temp.

I find zero lash with a adjustable push rod, then measure the length with a 8" digital caliper, then add the desired pre load to the measurement.

[Nabush]

Originally Posted by KingLT1

Are you factoring expansion into your cold measurement? once up to temp you will see around .013 of expansion so you will lose some pre-load compared to a cold measurement. So if those are cold measurements then the 7.825 should be ok at operating temp.

I find zero lash with a adjustable push rod, then measure the length with a 8" digital caliper, then add the desired pre load to the measurement.

When they give their 0.045-0.050 preload it is cold...so around 0.030 hot...

I think I should be fine either way...

[MattWll]

I also think that everything will be okay.