The Stovebolt Site Forums The Shop Area Engine Shop Is this mechanical or hydraulic 235 lifter?

Opinions, please:

1962 235 replacement engine - there is no useful Engine Serial Number (DR ###### CAL)

Is this a mechanical or hydraulic lifter?

Or, can that not be determined without removing the lifter?

Thanks,

Both modern mechanical and hydraulic lifters are made the same way- - - -the difference is the plunger on a hydraulic that can slowly displace the oil inside and adjust its height to be sure the valve closes. The mechanical lifter made on the same body has an upper section that cannot retract. You can get a valve fully closed and put firm pressure on the rocker arm with a pry bar for a few minutes and a hydraulic lifter will slowly bleed down and increase the gap at the valve stem to almost 1/8", then it will pump up again as soon as the engine is started. A mechanical lifter will not bleed down when the same procedure is tried.

Both types of lifter will have a snap ring in a groove near the top that holds the pieces of the lifter together. The inner piece will retract under firm, steady load on a hydraulic lifter.
Jerry

Thanks, Jerry,

That is what I thought.

I posted that for another person.

If he pulls the lifter out of the block, I assume that there is no "fool proof" visual way to distinguish between the style of lifters?

Just clamp the lifter in a vise with a 1/4" bolt or something similar bearing against the pushrod seat. If it's hydraulic it will pee oil all over the vise and the plunger will retract slowly. Don't overdo it on the pressure of the vise jaws.
Jerry

If the engine has been sitting for a while, I suppose he should run the engine for about 30 minutes before pulling a lifter?

Thanks,

It depends on whether the lifter has been in the extended or retracted position during the time it was not running. Doing a short run would be a good idea anyway just to be sure they're all pumped up, assuming they're hydraulic. An engine that sits for several hours with some of the valves open will bottom out those lifters due to valve spring pressure. A good lifter pumps up almost instantly as soon as it gets oil pressure.
Jerry

Thanks for this info. Tim was asking this Q for me while I got the account setup. So a follow-on question, I notice from the 1951 216ci that I took out of this truck, that when I took the engine down the lifters were set inside of an open cylinder bay in the block, such that the trumpet heads were exposed. On this 1962 235ci that I am installing/replacing it with, the lifters are different, they are nested inside of their own sleeve in the block, such that the trumpet heads are not exposed. Is that the difference to indicate it might be a Hydraulic setup?

The way I know for sure they are hydraulics is like Jerry said, they have a spring clip on the top of them and you can take them apart. Solid lifters are just machined hunks of metal with no moving parts. You can even shine a flashlight down a rocker rod hole and see if they are solids or hydraulic with the engine mostly assembled. The hydraulic lifters I get for these engines do not have 'trumpet heads', rather are the same size externally all the way up and down.

http://devestechnet.com/Home/Project1959235#hydrauliclifters

Hi Dave, looping back on this, apologies it's been a while I have been working on the brake system - did you say there was enough visual in the photo to ID these lifters as Hydraulic?
Lifters

Or should I try and pull one of the Lifters completely out of the block for closer examination? The block is a 235ci, Mfg date of May 25th 1962.

Thanks!

There does not appear to be a snap ring at the top, so I would say they are mechanical/solids.

Thanks Dave!