V8Astro Captain

iTrader: (1)

I have a set of plain-ole melling roller lifters right now. They seem to bleed down over night and when I start it in the morning I get all sorts of clattering noises for a second or two.

I was thinking that maybe these lifters can't handle the 110# springs I have.

Instead of buying another set of roller lifters would it possible/worth it to swap out just the plunger from a set of new GM flat tappet lifters?

Or am I way off base here?

radiateu2

Its not worth it go to enginekits.com and buy a set for 100 dollars

Vader

If you've got lots of time, a good set of calipers and hole gauges (or a really small telescope gauge) you probably could make the swap. You'd have to make sure the wear was on the plunger and not in the lifter body bore, and that the check valve designs are compatible.

Making a set of fast-bleed rollers?

V8Astro Captain

iTrader: (1)

So I need to measure the plunger and the bore in a couple places to check for tapering?

I know nothing about the internals of a lifter except that there is a plunger of some sort inside. How would I know if the check valves are compatable?

Fast-bleed rollers....hmmm, I have all winter to do this so please explain

radiateu2

hey I am curious as to what you are trying to achive with the lifters and what is the purpose of fast bleed lifters

V8Astro Captain

iTrader: (1)

Radiateu2, I have a set of Melling roller lifters I think are bleeding down. I'm leary of anything from AutoZone but I got them real cheap and figured they'd work out...

I also have a set of new (~15k mile) GM flat tappet lifters. I was thinking instead of buying $250+ roller lifters from Comp, I could just swap out the plungers.

Now Vader has my attention. I'm curious about the fast-bleed thing. I took apart some of the flat tappet lifters I have and I think I have an idea of what all that stuff does.

radiateu2

hey astro captain if it doesnt work out I know of 2 places you can get roller lifters from for around 100.00 for set. I am curious about the fast bleed lifters is it a bad thing or a good thing. Do you really have a v8 in an astro? lol

Vader

On the bottom of the plunger is a check valve. Most stock lifters will have a ball-type check, while some lifters have a disc. There should also be a disc valve above the plunger but beneath the push rod cup.

That check valve is what "locks" the oil in the body to make the lifter rigid so that it will operate the valve. Some of the oil also bypasses the upper disc valve and lubricates the push rod and valve. If the disc has a stiffer cross section and a bit more arc to it (they are not flat) it will allow the lifter to bleed off more oil before it "locks" hydraulically. That bleed, in addition to the spring pressure below the plunger and the sealing of the check ball are what makes a lifter "normal" or "fast" bleed off.

Unfortunately, I don't know what amount of clearance to suggest to control the bleed rate at whatever point you may desire. You'd have to experiment with different discs and springs, or swap the internal springs and discs from some flat fast bleeds into your rollers (if they would fit).