Camaro Forum Enthusiasts

I bought this 1967 Camaro a short time ago and it has the original numbers matching 327 2barrel engine.

I was told that the engine was rebuilt and had about 100 miles on the rebuild, and then it sat for the past 2 years without starting.

We got the car, and had to replace the battery, but got it running and it was running rough because of the old gas. We put some good hightest gas in and ran the old gas through the car. The oil, trans fluid and coolant were all clean and topped off. Once the old gas was gone the engine ran so smooth and quiet. The engine doesn't smoke at all and seems that the engine had been rebuilt.

We took a few small drives up to about 50-55mph and the engine ran great.

We took it on the highway to run the car a bit and we were on the highway running about 65-70mph for about 45 min to an hour and then the engine started knocking. We pulled over and the car was smooth and quiet but when you accelerate past about 2,500rpm or so the engine started knocking and sounded like a rod.

We pulled the pan while the engine was still in the car and started pulling the rod caps off. We started at the back and all of the bearings seemed silver with a bit of gray on the edges. But when we got to cylinder number 2 the bearing was all copper on the two sides but silver in the center and the journal on the crank had some wear marks and grooves. We pulled the engine and flipped it over and began to use a micrometer to take some measurements. Cylinder number 1 had a little bit of copper on the edges but nothing like bearing on cylinder number 2. We miked the bearing on cylinder 2 with the worn bearing and there is a .030 difference between the middle and the edges of the bearing. So it is of course wore down and we miked the part of the journal on the crank on cylinder number 2 and cylinder 1 and there is a 0.005 difference between the two.

We are trying to determine how to fix this problem. We know how to change the bearings but these are our questions.

Questions

1) The bearings are currently 0.030 meaning the crank has already been turned once or more. Can the crank be turned any more, do they make larger bearings, or is 0.030 as much as we can go? If the crank has been turned 0.030 what should the crank journal measure?

2) When we miked the journals there is a 0.005 difference between the journal halfs where rods number 1 & 2 are located. Is this two big a difference between these two halfs or is this an acceptable amount?

3) What could cause this bearing to have a problem?

Other facts, two of the rods have already been replaced for some reason and they are not the bearings/rods that are having a problem.

When we were loosening the rod bolts we noticed that cylinder #2's bolts were tight, probably tighter than they should have been. Could this have caused a problem, crushed the bearing?

Since the engine was sitting for a while could the bearing have gotten stuck to the crank journal and not allowed any oil to lubricate the journal.

Any help with this would be much appreciated.

We have only rebuilt maybe 2 engines ever and not sure what we should do to complete this rebuild.

Thank you

 

you can turn the rod jourals as far as you like so long as you can find bearings. i would look for another crank and connecting rods. no telling where the rods came from, is there a brand name on them, could be cheap china stuff. i would also consider new pistions if the ones you have are looking like some cheap stuff.

 

Most common issue with new ebuild by amutures that I find is not cleaning the crank after its been ground. They assume the machine shop cleans it and the machine shop assumes no one would assemble a motor without clean it.

What are you micing exacly? To mic the rod correctly you need to have it out of the motor and retoque the assmebly with the bearing in. Your not micing the thickness of the cap? becasue that means nothing.