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Hi fellow bolters! I have a question for you folks that have converted a babbit engine to insert bearing. I have a fresh 216, that has been machined to accept insert bearings. I am in the process of putting it back togather. I believe I have read that when you go to inserts, you no longer have to use shims in the rods. The machine shop checked all the rods, along with the crank shaft, and told me I would in fact not need shims. They have an employee there that has worked on Chevy 6's for years, and is good on them. Today, I put the newly machined rods, with new pistons back into the 216, and torqued them down to 50 lbs. The Chevy truck shop manual recommends 40-50 lbs. The rods don't snap back and forth on the crank. Is this right? Also, 3 of the rod bolts stripped when I started to tighten them up. Does anyone know where I could get new ones? The engine is a 1948 216.
Thanks for any advice!
KT
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1949 3/4 ton Chevy / 1950 1/2 ton Chevy

kt,
when you have the rods machined,they put little locating notches in the rods, for the inserts. There are two things to be careful of:

1)If those notches are not the correct width apart, the two bearing halves will not line up and you can end up taking up all the side play.

2) Secondly, sometimes the notches are not quite deep enough and this can cause the bearings to bind. In that case it is necessary to grind a little of the locating tang off, so that it isn't as deep.

If you have new wrist pins that are snug, that can stop the rods from snapping back and forth. With a newly machined engine with inserts, you should use plasti gauge for checking clearances.

Hi Truckernix! I did put brand new pistons w/new wrist pins in the engine.
KT
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1949 3/4 ton..1950 1/2 ton: Chevys

The rod bolts might have been overtightened in the past, or they might not have had enough lubrication to prevent stripping, but WHY did you keep tightening bolts after the first one stripped? I think new bolts and nuts are available from one of the restoration parts dealers, but once new bolts have been fitted, you'll really need to do a check on the roundness of the big end of the rod. I would suspect all the bolts now, and replace every one. I've always checked bearing clearance with Plastigage or a small piece of shim stock rather than relying on some subjective measurement like snapping the rod from side to side. Whatever clearance the bearing manufacturer specifies for the new insert bearings should be the specification to shoot for.
Jerry

Thanks for the help HRL! I wasn't going to rely on the side to side snap for a measurment, I just know that the rods are tight, and there is no movement as the shop manual shows. So, I wanted to ask you all. This is the first time I have ever completely overhauled a 216. You mentioned checking the roundness of the big end of the rod after fitting the new bolts, this will change the roundness? Thanks for the reply HRL.
KT

When a rod is reconditioned, it's filed slightly out of round, or in the case of your insert-bearing conversion, it's bored out to accept inserts. Torquing the rod nuts sets up some stresses, and then the rod is honed perfectly round, and the correct size. Pressing new bolts in will sometimes create stress points that pull the big end out of round, so when I was working as a machinist, I'd always file the mating area of the rod and cap a little before installing new bolts, then hone them round again. I'd only reduce the size a couple of thousandths, but it made for an excellent end result after honing the rod for a final fit.
Jerry

For myself, I would not torque anything else before I checked that torque wrench. Especially, if it is one of those snap wrenches. I've seen one that was 30% off.

if the rods are locked up tite theres something not right you have a problem you should be able to turn the crank

kt,
when I put my 216 together with the converted rods, I test fit the rods without the piston, to see how they felt. Also, if your rod bearings are tight, you won't be able to turn the engine over.

The rod bolts in the motor are not pressed in. One of the suppliers, probably Chevs of the 40s will have the bolts.

Hi Bolters! Well HRL, today I went to see my friend at the machine shop. I told him that I torqued the rods to the specs in the Chevy Truck Shop manual. That is 40-50 lbs. Monty told me that I needed to torque them no more than 30-35 lbs. So, lesson learned. A good peice of advice for other bolters! I was just following the shop manual, and thought I was doing the right thing. He also told me as you did that I would need to take the pistons back out of the engine and bring them in for a check, once I locate some new bolts. I will replace them all as you said. So far, no one has them. I am going to check one more source for some used ones. Well, back to the drawing board!!!!!
Thanks again!
KT

kt,
here is a link to Chevs of the 40s where they list the rod bolts and nuts. Did you see this?

http://www.parts123.com/PartFrame.a...softhe40s.com&TITLE=Chevs_of_the_40s

Click on the link, type in rod bolts under the description and click on search. They have them listed.

Hi Truckernix!!! I called Chev's of the 40's when I got home from work today, and Velvet told me they didn't have any bolts. What they did have at one time, were used.
Thanks anyhow for the lead!
KT

KT,
I would sign on to the VCCA site and put a request in the parts wanted. I have been able to get some pretty obscure parts by doing that.

If you want used bolts I can help.