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  View original topic: How to repair a lifter bore?
turdburger Sat Mar 18, 2006 3:57 am

Hi, I have manged to kill a cam follower bore in quite a new case which is causing low oil pressure :( . Time wise I have had to bite the bullit and get another case to use, but it would be nice to get the old one repaired to get back some cash.

How would you go about it, or should I say get a machine shop to go about it?!

nsracing Sat Mar 18, 2006 4:22 am

IT is a machine shop job man.

The hole needs bored and then a new machined piece pressed in and then resized for the lifter bore size.

It is slightly tedius and have some set up time involved.

RIS Sat Mar 18, 2006 5:36 am

Yes, definitely a machine shop job. See what Nick can do for you, if not Valley VW in PA does nice lifter bores for a fair price. I'd think twice about sending the case to RIMCO for lifter bores, do a search...

Alan_U Sat Mar 18, 2006 8:44 am

Use silicon bronze sleeves if your going to all that trouble to sleeve the lifter bores. That material is by far better than aluminum sleeves.

Steve Hollingsworth does a killer job in sleeving the case. He is probably more expensive than Valley VW. Steve uses a jig to properly reference the lifter bore location. Also he wants your lifters so he can properly fit the lifters with the new silicon bronze sleeves.

If you got a worn out hole and send it to Rimco I was told they use the old wobbly hole as a reference and just oversize the hole and press a new sleeve in :?: so basically if the lifter bore is "off" it is just gonna be "off" again but with a new sleeve in it :cry:

The possibility of a quickly worn out bore is due to a bad casting of the lifter bores in the first place. I said "possibility". If Steve does it you know its gonna be spot on.

AJTowers Sat Mar 18, 2006 8:49 am

Will Al-bronze sleeves work with ceramic lifters? Or, do you need steel sleeves?

Alan_U Sat Mar 18, 2006 12:02 pm

AJTowers wrote: Will Al-bronze sleeves work with ceramic lifters? Or, do you need steel sleeves?

I'd use silicon bronze.

nsracing Sat Mar 18, 2006 12:56 pm

/Silicon Bronze is NOT cheap..especially in that size. It is a solid barstock under 2 inches. Aluminum Bronze is not that much cheaper either. The bronzes are harder to machine too. Silicon Bronze can be used also for seat materials. It is that hard and durable.

6061 T6 Aluminum is okay..cheap enough and durable enough.

It all depends on how much you love that case for the repair of which material. The Bronzes will be expensive.

You do not really need a jig to machine the new hole in. The most important thing is finding the "squareness" of the lifters VS. the camshaft.
The lifter has to be perpendicular to the cam. You can find this "tilt" by indicating the other holes.

A jig is used so you do not have to indicate anything. Just slap it on and stick a reamer in there. This process has a tolerance too..usually lower. The set up time is shorter...VS. setting up without a jig.

Alan_U Sun Mar 19, 2006 10:18 am

nsracing wrote: You do not really need a jig to machine the new hole in. The most important thing is finding the "squareness" of the lifters VS. the camshaft.
The lifter has to be perpendicular to the cam. You can find this "tilt" by indicating the other holes.

A jig is used so you do not have to indicate anything. Just slap it on and stick a reamer in there. This process has a tolerance too..usually lower. The set up time is shorter...VS. setting up without a jig.

What if all 8 holes are worn oblong? Then the bores will be all over the map. My friend who is a machinist has made a jig specially for this purpose of proper alignment. The next case I'll be getting him to do my silicon bronze bushings.

I have a hunch that the combination of crappy lifters and incorrect alignment of the bores (from casting of mag cases and aluminum) has to be a contributor of destroyed lifters and cams.

RIS Sun Mar 19, 2006 10:28 am

Alan_U wrote: I have a hunch that the combination of crappy lifters and incorrect alignment of the bores (from casting of mag cases and aluminum) has to be a contributor of destroyed lifters and cams.

I agree, very good hunch...

nsracing Sun Mar 19, 2006 11:46 am

Alan,

It is NOT that hard to find centers and levelness with a guage on a milling machine. :roll:

The lifter bore could be oblong to hell but you can still find the
squareness. Just follow the levelness of the camshaft..indicate that with a guage and set the case like so on the table.

Now..for the "tilt" of the lifter itself, indicate the lip of the top of the lifter bore. These surfaces are machined square..parallel to the camshaft itself. (This is the area that gets cutdown some when you use high lift cams.) Indicate that and you WILL find square!!

OR... just machine a dummy lifter, insert that in the bore, set it square with the top lip, and indicate from that.

There are jack stands that are adjustable designed for milling machines so you can machine odd shape items. It is all in the tooling. :P

This is simple machine work. NOt hard at all.

Alan_U Sun Mar 19, 2006 12:09 pm

nsracing wrote: Alan,

It is NOT that hard to find centers and levelness with a guage on a milling machine. :roll:

The lifter bore could be oblong to hell but you can still find the
squareness. Just follow the levelness of the camshaft..indicate that with a guage and set the case like so on the table.

Now..for the "tilt" of the lifter itself, indicate the lip of the top of the lifter bore. These surfaces are machined square..parallel to the camshaft itself. (This is the area that gets cutdown some when you use high lift cams.) Indicate that and you WILL find square!!

OR... just machine a dummy lifter, insert that in the bore, set it square with the top lip, and indicate from that.

There are jack stands that are adjustable designed for milling machines so you can machine odd shape items. It is all in the tooling. :P

This is simple machine work. NOt hard at all.

you speaking greek to me ? :D

I'm no machinist or its techincalities. I just think the jig idea is fool proof for an experienced machinist and every single lifter bore job ever done will be ultra consistant in geometry.

I recently bought 4 AS41 mexi cases just because I wanted a personal stash for years to come. My friend inspected them thoroughly and gave approval to all the measurements and machining. There are some cases where he's seen lifter bores out.

You'll see some hardcore performance V8 guys extremely particular on lifter bore location and if they are out they toss them out and give them to others that dont know any better. This is why I express concerns with lifter bore locations in the location of flat 4 lifter bores.

This may be part of the puzzle in cam/lifter problems in out Vdubs. Tool steel lifters and ceramics can take more abuse and maybe more resilient to "lack of" lifter spin. Just a hunch but V8 guys are convinced this is a critical area of inspection.

Jody '71 Sun Mar 19, 2006 12:38 pm

I can speak on behalf of Nick. His machine work is excellent. He just built me a 1776, tapped for full flow with the Berg kit et al. I highly recommend him. He loses me in the technicalities but has the patience to deal with those that are not so well informed when it comes to an on-hand project like mine. He's even going to assist me in the final break-in when installation is complete by myself as part of his cost. Nick KNOWS.

Charlie



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