Installing lifter bore bushings

[DonWG]

I'm in the process of getting the tooling together to bush the lifter bores on my TA block.

Can anyone give me a press fit specification for a 1" bronze bushing to an aluminum block? I'm thinking .0015".

Lifter to bushing clearance? I'm thinking .0015" - .002".

I'm moving up to a larger diameter lifter body with a larger roller assembly for increased strength.

[gnxtc2]

Don't know if this helps you but BHJ already makes a fixture for this.

Billly T.
gnxtc2@aol.com

[DonWG]

I've been looking into the BHJ tooling. I already have the Bor-Tru kit for the Bucik V6 and steel and aluminum torque plates for boring and honing. The lifter-Tru kit is rather expensive and I'm not sure if I could make it pay for itself with the volume of engine work I do. The job can be done with simpler tooling, just not as fast.

[FHW]

First thing i would do is make a bushing to size then use test piece of aluminum as close a type as the block and try different press fit's ,you have to be carefull with aluminum to much a press fit and it will just ghall up as you press in the bushing.

[DonWG]

This is what I've decided to do.

Press fit into block will be .001" - .0015" installed at room temp using a sleeve locking compound.

Lifter body to sleeve clearance will be .0015" - .002".

I haven't decided what size feed hole to use in the sleeve to meet the oil gallery. I may go with a .028" orifice to somewhat restrict oil feed to the upper end. T&D says this is adequate.

[BAGN]

Originally Posted by DonWG

. . . . I may go with a .028" orifice to somewhat restrict oil feed to the upper end. T&D says this is adequate.

I'm in the process of tearing my new motor down due to machine shop drilling a 1/4 hole in my lifter bore. I think i'm gonna go with a .035 hole in mine. Let me know how yours works out.
Also, Anybody tried the big ford lifters? I might be doing those as well.
CC

[DonWG]

To clarify. I'm leaving the feed to the lifter gallery wide open. I am restricting from the gallery to the lifter bore at each lifter bore. .035" might be better from the stand point that debris will be less prone to plug the hole. I'm still deciding which hole size to use.

During this re-sleeving process I'm also moving up to the Crower .903" size body. It has increased pin, needle and roller size. More durability. It seemed like a good idea to me. There's no need to change cam lobe profile when stepping up to .903".

[bison]

.001 seems kind of tight Don. Id think it would ghall up the bore as you pressed through. Maybe if you deep freeze the bushings before pressing you wont shave off any aluminum.

[turbodave231]

I beleive .001 is not enough of a press fit for bronze in aluminum. I would shoot for at least .002". Here is my reasoning: The rule of thumb for installing bronze valve guides is at least .002 press fit in aluminum. The rule of thumb for Valve seats in an aluminum head are .008" The lifter bushings won't see the same amount of heat as the valve seats, but perhaps closer to the level of heat at the valve guide. You certainly don't want to drop a bushing due to insufficient press fit.

Regardless of the press fit you choose, I'd recommend a small lead-in chamfer on the bushing to be sure you don't grab aluminum on the way in. I'd also heat that block to 300 degrees in and oven and chill the bushings before pressing the bushings. I'm not sure I'd use a locking compound. Any locking compound acts as a barrier for heat transfer and may not help lifter bore life.

I understand that Champion Racing installs bronze lifter bushings in Buick engines. You might consult with them to see if there is anything specific to look out for when doing this operation. Diamond Racing supplies bushings. You might ask them for recommended press fits in aluminum. I'd be interested to hear what they say.

Good Luck......and post some pictures.

Dave

[DonWG]

Thanks for the input guys. I have some extra bushings I'm going to use to experiment with, like FHW suggested. It's funny. I pound bushings all day long in transmissions, and this bushing operation has me nervous as heck.

I'll be experimenting with a heat/chilled method (no locking compound), room temperature method with locking compound and without, different press fits, the affect of different bushing wall thicknesses on the amount of press fit needed, and anything else I can come up with.

The point about the locking compound and heat transfer is a very good one. I'm aware of the press fit required for guides and valve seats. That's why I'm questioning the amount for the lifter bushings. In the transmission world, you see, roughly, .001" per one inch diameter, but all the components are rotating in the bore, not reciprocating like a valve guide or lifter bushing. Locking compounds never seem to be a concern when used in transmissions. It's even recommended on front pump bushings that support the torque converter hub. Especially on aluminum pump bodies. The reason is that after the original bushing is removed, you will not achieve the same press fit as you would have with a brand new pump body. So the surfaces are prepped and sleeve locking compound is used to hold the bushing in place. The aluminum pump bodies also expand at a higher rate than cast iron bodies and bushing retention becomes more of a problem. The pump bushing also sees an awful amount of heat in its life. The torque converter can generate enough heat to turn steel blue. Even under extreme conditions like that, I can't recall ever seeing damage to a bushing that could have been directly related to bad heat transfer. But, it's a good point and I'll be looking into that very carefully. Thanks again. I'll make that call to Diamond Racing too.