lifter grinding

[jake197000]

i know this has been talked about before but dont feel like i found a diffinitive answer.i was thinking of building a fixture to grind them on my surface grinder.is it ok to grind them flat?i thought they had a radius but someone said nobody grinds them that way now.i could just send em in but like to try to do things my self.ussually just buy new but lincoln v-12 lifter bodys are not being reproduced.hydralic ones i mean.i send my cams to effingham to get reground.

[statsystems]

i know this has been talked about before but dont feel like i found a diffinitive answer.i was thinking of building a fixture to grind them on my surface grinder.is it ok to grind them flat?i thought they had a radius but someone said nobody grinds them that way now.i could just send em in but like to try to do things my self.ussually just buy new but lincoln v-12 lifter bodys are not being reproduced.hydralic ones i mean.i send my cams to effingham to get reground.

Mike Jones posted in another thread that the radius is 56-58 inches. They can't be flat.

[modok]

They have to match the cam.. What shape is the cam?

[modok]

yeah, probably 60% are like that but instead of guessing, lets measure the cam. I don't think I've ever seen one.

[Geoff2]

Here in Australia we re-face FT lifters all the time, have done for decades, reason being the high cost to buy US lifters. Now with the CRAP lifters being sold, re-facing your old factory lifters or 25+ yr old lifters guarantees you get a quality lifter. Can be re-faced 2 or 3 times. The final finish is very important. Even though I can get them re-faced locally, I send my lifters interstate for a perfect job.

[jake197000]

ok thamks ill just send them in.been wanting a lifter grinding machine for years but man they are hard to find.

[dwilliams]

Most lifters (well, American V8 lifters) come with a slight crown. But they don't keep the crown very long in service. Most seem to quickly wear to very slightly concave, then show no further signs until they start to pit at high mileage.

Not all lifters from the same engine seem to wear at the same rate.

Back years ago I checked a lot of used lifters by rubbing them across 600-grit sandpaper. Even low mileage ones usually showed concavity. Didn't seem to hurt anything in service. For my own engines, I just cleaned and re-used them.

[dwilliams]

wanting a lifter grinding machine for years but man they are hard to find.

Sioux used to make an attachment for their valve grinders. It worked like the valve tip dresser and just faced the lifters flat.

You could make a 50" or whatever radius tool easily enough with a holder, bracket, and swinging rod of appropriate length. I thought about doing that once, and again during the "lifter shortage" a few years ago, but it looked like it would become another fixture that generally wasn't worth the time to set up...

If I did a lot of antiques or exotics where correct OEM lifters were crazy expensive or unobtainium, I'd definitely make one, though.

[jake197000]

I know about the Sioux grinder.i have one.so whats up with the flat lifters ?I played with it but didn't like the finish I could probably get a mirror finish wiyh the surface grinder.if the lobe has taper why cant the lifter be flat ? apparently Sioux thought it was ok.im so confused.like I said I just buy new and send the cams to get reground.i have no problem sending them in its just that I want to know.

[PackardV8]

The taper of the cam lobe and the corresponding radius of the lifter are designed to force lifter and pushrod rotation for even wear.

The early Buick V8 is one which comes to mind as a true flat tappet. Most other GMs and FoMoCos had a very large, on the order of 100" spherical radius. The Mopar, Packard and Studebaker V8s used 30 - 40" spherical radius. Most small shop tappet grinders have an adjustable table which cannot produce a true radius, but approximates it with a conical shape.

FWIW, I've noticed recent Johnson lifters are not supplied with the original Packard/Mopar 30" radius, but more like the SBC larger radius. Anyone have any idea as to WIGO, as Johnson won't answer the question.

[jake197000]

I get the ideaand know its important but when you pull some of these old worn out engines apart and the lifters are concave it looks like there still turning and the lobes don't look that bad.

[DaveMcLain]

That outfit called Mitspa supplies "rebuilt" lifters that are reground and they are nicely done and very reasonable. He might be a guy to ask about what crown a new lifter should have out of the box.

Ford Flathead V8 and the 2N, 8N, 9N tractors have a true flat lifter as far as I know and I've refaced them before.

[Truckedup]

The lifters can also be offset from the cam lobe to promote spin...I used to paint a stripe on the pushrods to see the spin before doing a valve adjustment...You might see one or a few not spinning evenly ...The start of trouble...

[SchmidtMotorWorks]

You could do it with a surface grinder and a spin fixture.

Use largest cup shaped wheel you can fit on your machine and dress it so that the front face is dished with a conical shape at least 30 degrees and the edge is has a radius about 0.1".

Set up horizontal spin-fixture so the lifter tilts down a few degrees (the exact angle depends on the wheel radius and desired radius)

Set the level of the wheel so the center of the lifter is coincident the front tangent of the radius on the wheel.

Feed the rotating lifter into the side of the wheel.

Probably start with a 40 to 60 grit wheel to rough, 120 grit to finish.

[modok]

The collet or....whatever holds the lifter needs to be very good so you don't have any runout on the face.
yes the offest of the lobe ultimately gives you rotation, but the whole deal with the radius face and cam taper is to get contact started in the middle of the lobe.
If a lifter is flat and the cam is flat, then anything less than perfect you have contact at the edge.

Could work just as well with a flat lifter and a crowned lobe, but that wasn't a popular way to go, probably harder to make, and not as long lived, as the lifter will always tend to wear concave, makes sense to start out convex.
These days, better harder materials and lubes, wear is less of a concern, so less severe crown is what most are going towards.