Yeah, I hear ya...I've been through 4 different oil/viscosity changes to try to get this right LOL

 

I'm willing to bet they're Scorpion Lifters. The price is about right, as is the lifetime warranty.

I've been wrong before though....

 

Yes my valve train noise was insane compared to it now... Of course there will always be a little bit of noise, but its silent compared to how it was with the factory LS1 lifters

 

Food for thought for next time the heads are off. What preload do those Morel require?

 

Per some recent threads on how many turns equals what pre-load, 1-3/4 turn of the rocker arm bolt from zero lash to 22 ft-lbs equates to ~0.110" of lifter pre-load.

https://ls1tech.com/forums/14943159-post36.html

Main thread:
https://ls1tech.com/forums/generatio...questions.html

Another good lifter pre-load thread:
https://ls1tech.com/forums/generatio...-pre-load.html

LS7 lifters have 0.166" total plunger travel.

 

Kinda scary, IMHO to think that setting them that deep could possibly lead to roughly .180 additional lift at the valve....if they were to pump up fully @ high rpm.

 

0.110 pre-load is kind of deep, but if he's got LS7 lifters they have 0.166" total plunger travel ... and half way (0.083) is the recommended pre-load by GM. So he's only 0.023 too deep. Maybe LS7 lifters like more pre-load and that's what quiets them down (?).

Part of the pre-load equation is also knowing what lifters you have and their total plunger travel.

 

I would think that bleed rate would be more of a concern than actual plunger travel. I would also think that being nearer to the TOP of plunger travel would allow for less worries related to lifter pump-up....and that if anything, LESS preload on the LS7 lifters would be more beneficial....allowing for more of a hydraulic cushion between the bottom of the plunger, and the inside bottom of the lifter body.

 

Not debating what's the "best pre-load" for a specific lifter. Just saying GM recommends mid plunger travel on every lifter I've seen from them.

My LS6 has the lifters set to mid-plunger travel (ie, stock setup), and they are quiet.

You'll find that about half the members here think that less pre-load makes them more quiet, and the other half thinks more pre-load makes them more quiet. Everyone can't be right if split in their thinking.

I think lifter pre-load is the most talked about and most mis-understood topic on any LSx chat board.

 

Agreed.

 

I have Vortec 350 lifters. The engine was a rebuild my dad did about 10 years ago and a stray nut found an intake port with an open valve and he never even knew it. It popped a piston on start up and he pulled it to replace with another engine for the customer.

My lifters were toast and I didn't know until the last minute. Using the barely ran lifters saved me 4-5 days wait on getting the car back together so I could go back to work.

Should I be worried and try some 7.375"? I tried 7.35" and the car was useless. Geoff recommends a 7.425" with stock shortblock and his cams and the only difference is my heads are shaved .010". I used Felpro stock replacement gaskets.

 

They would only pump up the additional .180" if you floated the heck out of the valves.

 

I agree.

 

Well you can understand I'm nervous about spending more money on 7.375" when the car was unusable with 7.35".

It sounded like a stock cam (no lope), sounded like 2 industrial sewing machines under the valve covers (I could hear them rattle over 3" exhaust dumped at the axle), and had no throttle response or upper rpm power.

Put the 7.4" back in and it runs good. Ran 7.54@92mph 11.92@111mph Sunday. I just don't want to break anything.

 

Tonight I'll take apart one of my original LS1 units as well as one of the new LS7 units and get some photos and travel measurements.

BTW, I believe the same lifters are used in the later SB chev.

Ron

 

You've probably already seen this chart a few times, but will be interesting to see how your measurements compare.

 

Agreed. But....as you know...mis-shifts can and do happen. That's all I was meaning to point out.

 

So, looking at that chart and converting MM to inches, it calls for preload of: .1173 for my old Vortec lifters

That means I am actually right on the money within .007 of recommended preload correct?

 

Yes, if your talking about lifter GM P/N 5234670 in the chart I posted.

 

Pretty sure it would have to be. Engine was an 88 or 89 5.7 Vortec from a passenger van.

Sorry for the thread hijack OP but this has been very helpful for me. Hopefully your new setup is quiet too.