• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Hydraulic Lifter Preload Advise

Road Grabber

Well-Known Member
Local time
8:38 AM
Joined
Apr 14, 2020
Messages
756
Reaction score
173
Location
Sarasota Florida/NY State
I had some adjustable pushrods made for my 383. I used a setup like this with my 440 and was very happy with it.

Stock stamped rockers.

Once I get zero lash what preload would you recommend?

One rotation?
1-1/2 rotations?

Thank you in advance.
 
A lot depends on your adjuster screw threads. Typical 3/8 24 tpi one turn is about .040 preload. What lifters? flat or roller?
 
A lot depends on your adjuster screw threads. Typical 3/8 24 tpi one turn is about .040 preload. What lifters? flat or roller?

Flat hydraulic

I can see your point. I’d have to check the thread. Is there a distance that you would recommend?
 
Flat hydraulic

I can see your point. I’d have to check the thread. Is there a distance that you would recommend?
I would be fine at .040 preload. What are you using to measure for the correct push rod?
 
I would be fine at .040 preload. What are you using to measure for the correct push rod?
I see you have adjustable push rods. Take one apart and see what the thread size and pitch is.
 
I see you have adjustable push rods. Take one apart and see what the thread size and pitch is.

Yes I had Smith Bros make them. Very reasonable price just as information for those reading this. I wanted to adjust each one since the shops don’t typically grind the valve stems the same height afterwards. My shop couldn’t find a spec for valve stem height and didn’t grind them the same height so I decided to just get the adjustable pushrods and be done with it. I used a set of Crane adjustables before on my 440 and it ran great.

Once I find the pitch you would shoot for .040?
 
Yes I had Smith Bros make them. Very reasonable price just as information for those reading this. I wanted to adjust each one since the shops don’t typically grind the valve stems the same height afterwards. My shop couldn’t find a spec for valve stem height and didn’t grind them the same height so I decided to just get the adjustable pushrods and be done with it. I used a set of Crane adjustables before on my 440 and it ran great.

Once I find the pitch you would shoot for .040?
Yes. If the push rods have a 3/8 fine 24 tpi once you get zero lash one turn on the rod longer would be just about .040. .04166 to be exact.
 
Yes I had Smith Bros make them. Very reasonable price just as information for those reading this. I wanted to adjust each one since the shops don’t typically grind the valve stems the same height afterwards. My shop couldn’t find a spec for valve stem height and didn’t grind them the same height so I decided to just get the adjustable pushrods and be done with it. I used a set of Crane adjustables before on my 440 and it ran great.

Once I find the pitch you would shoot for .040?
The factory way was to use a go no go tube gauge to slide over the valve. Then grind as necessary.
It'd be nice to have that factory tool
 
At first I thought the shop couldn’t find the spec or didn’t bother to look. I couldn’t find a valve stem height spec either. I always thought it was pretty standard for a shop to finish a valve job with a grind across the top.

Thanks for the intel. The adjustable pushrods are a nice setup. I did have to estimate the length I wanted but so far it seems to have worked out. I measured the stock rod and estimated the factory preload and allowed for adjustment with having to extend the threads too far. You have to specify the rod diameter and tip design as well.

It’s much cheaper to have the adjustable rods made than to buy them. An Isky tech gave me the suggestion.
 
Auto Transport Service
Back
Top