The Stovebolt Site Forums The Shop Area Engine Shop How to tell what has been modified?

Howdy All,
I have done some research here on the 216 babbets, which is what I think we have. I am still a little unsure of the how the whole babbet system works. But I am trying to tell if this one has been modified to the newer style of insert bearings. Can anyone point out the signs for me?

Thanks.
Ken Jones

Welcome to Stovebolt, Ken & Sons!

See if this previous thread can help you out any.

What's the year & model 216? Post a few more times & you can link us some pictures of the engine & what it resides in.

Good luck!

Brad

If your engine has 15 head bolts it is a 216 or a low pressure 235.

If you have an oil distributor on the driver's side of the block, you have a 216 or a low pressure 235.

If you drop the pan and check a rod bearing, you can determine if it is a babbitted rod bearing or an insert rod bearing (this is the only way you can tell it a low pressure engine has been converted to insert rod bearings).

Post the various casting codes and serial numbers and someone will tell you more about your engine.

Thanks Guys,
It is a 216, casting number GM32 3835794, I learned this from this awesome website. I wasn't clear on what I'm not clear about. It is a 216, 2-bolt valve cover, large push-rod cover panel etc.

I am not sure I understand the difference between babbets and what you would find in a later model stovebolts.

This is my family's 2nd stovebolt. I had a 51' 1/2 ton when I was 17...a long time ago. My son is now 15 and decided he wanted the same thing so here we go! I'm not sure who is more excited, him or me.

Mine had a 62' 235 with all the advancements. I see the big differences between the two but I never had to deal with rods and bearings etc. Hence the problem...I am not sure how tell if this 216 has been up-graded to insert type bearing or not or if the head has been modified for modern gas.

This truck has been sitting for a long time before we got it. It wont rotate and it has a bent rod and the internals seem to be gummed up pretty good. I have the feeling that we can disassemble it, clean it and put it back together it would work. But since it is apart, it would be good to address anything necessary.

With all that, I am back to the original question. i am not sure i understand what babbet was and how these differ from later rod or main bearings.

Any pointers would be greatly appreciated.

Photos here:
Photobucket

Thanks.

the babbitt refers to the rods having babbitt applied directly to the rod, the only way to tell if it has been converted is to take it apart and see if there is insert bearings, or if there is babbitt applied directly to the rod. (if the bearings come out they are insert, if they are one piece with the rod it is babbitt.) Either one is perfectly fine, as long as the clearances are in the acceptable range. If you don't know what babbitt is, just refer to google. It is just easier than trying to explain in my own words. If you have a bent rod, that piece won't clean up and be usable again. The heads don't need to be modified, these engines have such low compression and produce such little heat it won't matter.

The term "Babbit" applies to several different soft metal alloys of lead, copper, tin and antimony. Depending on the percentage of each metal used it can vary from soft enough to scratch with a fingernail to very hard. The alloy used in Chevy connecting rods is called "high speed Babbit" and it's pretty hard, durable stuff. A layer of the soft metal is bonded to the big end of the connecting rod and the rod cap, then bored to the size of the crankshaft journal. Shims are placed between the rod and the cap to allow for oil clearance so the bearing can be lubricated by a dipper attached to the rod cap. It lubricates the rod by dipping into a trough attached to the oil pan at idle speed, and a stream of oil squirts directly into the dipper at higher speeds. When the Babbit metal wears, shims can be removed to regain the proper clearance.

Later model engines such as the 54-up 235's and newer have the Babbit bonded to a removable steel backing, rather than being bonded directly to the rod. These can be replaced without changing the rods. There is a conversion bearing available for the dipper-equipped engines for removable bearings, but the Babbited rods require some custom machining to use them. Pull a rod cap and see if there's a removable insert. If so, you've got modified rods. If not, reassemble the rod with exactly the same number and placement of shims you found when it was disassembled to maintain the proper oil clearance.
Jerry

I appreciate the help guys,

We worked over the weekend and since they do not come out, it appears that I still have the babbit installed. I did see a few posts that talk about upgrading to newer inserts. Is that of much benefit or just out of necessity? We did keep all the bits in order so that they can go back in order.

My concern comes from these new photos. Can someone tell me if the rod ends are supposed to look like this?

Rod ends 22 Aug 14

Nope- - - -do not try to re-use those rods! The bearing material is flaking off and filling up the clearance between the rod and the crankshaft. It will eventually cause a catastrophic failure that will ruin the crankshaft and/or break a rod off and spin it around inside the engine. Measure the crankshaft journals with a micrometer to see if they have been ground undersize, and to see if they are still round. If you decide to go back original, there are still plenty of Babbit rods available. I buy them on Ebay every chance I get. Just be sure the size of the rod matches the crankshaft.

If you choose to have the rods machined for insert bearings, most good automotive machine shops can do the job. There's really very little reason to pay the outrageous prices the specialty machine shops demand. I am currently building a fixture for my lathe to do the rod boring, but it's not complete yet. When it is, I plan to offer that service to Stovebolt forum members at a bargain rate. Good luck!
Jerry

Thanks Hotrod. Looks like we have s'more thinking to do. I appreciate the help and a great website!