The Stovebolt Site Forums The Shop Area Engine Shop 235 engine shims

Took my 235 (1955 passenger car motor) to my brother's shop today. We took it down to the block and head. His only question was about the shims used. We saw some under the crank clamps (not sure of the technical term for that - the brackets that hold the crank in). Can we replace those, or buy them from someone? I looked through Carter's and I don't see them, even with their engine rebuild kits. Anyone know how to get these for reassembling the motor?

They're called Main Caps. The procedure for how to install the shims as well as how to determine if they are necessary is described in the shop manual, if you do not have one, it is available online. for availability, you should be able to get them from the local parts store, like Napa. Fel-Pro also still includes them in their overhaul gasket sets, along with the Plasti-gauge to measure clearances.

The metal in a soft drink can or a beer can makes a handy source for shim material. Just trim out a few with a small pair of scissors. Most professional-grade parts stores like NAPA will probably be able to supply you with roll brass for shims of various thicknesses if you need it. Pre-formed shims are nice, but not really necessary.

Edit: The Federal-Mogul Master Engine Bearing catalog used to list a part number for main bearing shims- - - -don't know if they're still available or not.
Jerry

Hey Jerry, that beer can tossed in the bed of the truck might work in a pinch if you needed a .004” shim. I’ll bet that’s some of that dirt track technology right?
This particular cadaver actually measures .0038” but more often than not .001” increments are more appropriate for adjustments. The Busch NA shim stock sample:
http://www.pbase.com/dennygraham/image/129670850/large
I’ve found it better to just pick up a few rolls of shim stock from McMaster Carr to keep around the shop. That’s enough for you to do a few dozen engines. The laminated stack comes in .002” increments and the individual 24” rolls are available for a couple bucks in .0005”-.00075”f or plastic and .001”- .0015”- .002” and up in Brass or SSteel. That gives you a much better chance of dialing it in correctly. If you really want SS .0005” and .00075” that IS available also but only in larger rolls costing about $40 but what the hey, that’s enough to do a few hundred engines.
Denny Graham
Sandwich, IL

If you can get the mains bearings down to the absolute minimum clearance, you will have a good chance at having a successful rear main seal.

That's exactly spot on Fred, I've come to the conclusion that the major reason the rear rope seals leak is too much rear main bearing clearance. Unlike the rubber lip seals, which put pressure on the sealing surface, the rope seal is not resilient and does not spring back when compressed. If your rear main bearing has .004" or .005" clearance that the seal will eventually be seeing after it is hammered into it’s final position. The space that it needs to seal is under pressure and it will pump oil out thru a .005” gap quite easily. This will account for the common experience that many people have, the rope seals for the first few thousand miles and then they begin to notice a drip which continues to get worse over time.
Denny Graham
Sandwich, IL

Actually the beer can shims work best on rods, where there might be a .010" to .020" thickness of shim between the rod and the cap. The thin ones are used to tweak the final clearance, but those soft Babbit rod bearings need adjusting often enough that they are usually rough-finished with plenty of shim pack between the rod and cap before the initial bore is cut. I've got some New Old Stock military 235 rods with a single .020" shim between each side of the rod and cap. The rod is bored to standard diameter with the shims in place. As the rod wears, they get replaced with a feather shim that's peeled away a thousandth or so at a time to compensate for wear.
Jerry

Wall thank the lordy I won't have to worry bout that on me 216. I just got her back from the shop and when I need an adjustment I'll just call EGGE and have them send me out a new set of inserts.
That's a new one on me Jerry, never heard of that much shim for any bearing, unless it was for the engine on board the Shanghi steamer.
I told them I wanted all of the old parts for the autopsy. Man you should have seen the assortment of shims that came out of this engine. Brass, SS, Alum, Paper.
DG

Just got done rebuilding my 55 pass engine the con rods don't use shims and the mains you can order from a engine rebuilding shop.What ever shop You're going to use to check everything, the one I used got me the con and main bearings and the main shim kit for less than I could of got on the supplers I also needed a new cam and lifters.

Pete

Federal-Mogul shim kit part number, #FSM-124 S