Thread: different connecting rods?

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So would that mean just a couple of gramms more in the big end of three rods would cause such strong vibration? As I say, it can't be the fan or the TC, because I took them off to check whether it was them and it didn't make a difference...
The last turning thing outside the engine I haven't checked yet is the lower pulley. I'll have to get some kind of auxiliary cooling pump before I can check that, though.
Thanks for the input,
Max

Originally Posted by MadMax

So would that mean just a couple of gramms more in the big end of three rods would cause such strong vibration? As I say, it can't be the fan or the TC, because I took them off to check whether it was them and it didn't make a difference...
The last turning thing outside the engine I haven't checked yet is the lower pulley. I'll have to get some kind of auxiliary cooling pump before I can check that, though.
Thanks for the input,
Max

The oil splashing around from the pan up to the rods will make it vary more than a few grams.
Are you sure you have the right balancer on there?

Hi Erik,
well, I'm not completey sure. There are many kinds of balancers, mine is for internally balanced 350s. I just bought the same size I had on before so that my timing tab would fit, the new one is slightly lighter. But I didn't think it would make much difference in a not-race application? What balancer would you recommend?
Thanks for helping, anything before I pull that engine out again...
Cheers, Mad

Originally Posted by MadMax

Hi Erik,
well, I'm not completey sure. There are many kinds of balancers, mine is for internally balanced 350s. I just bought the same size I had on before so that my timing tab would fit, the new one is slightly lighter. But I didn't think it would make much difference in a not-race application? What balancer would you recommend?
Thanks for helping, anything before I pull that engine out again...
Cheers, Mad

Any of the internal balancers will work.
Make sure it does not have a metal piece on the inside of it.
It will be about 4 inches long and about 1/2 to 3/4 an inch thick and in a shape of an arch.
If it has this on there it is a balancer for a ext. balanced engine.

Hi Again,
I've now double checked to make sure it's the right balancer and the flexplate is also correct and straight. But my bottom pulley is slightly bent. However: I've traced the real problem to a completely different source: The ignition. I just thought I might try and fiddle with it, and hey presto, it did it! The vibrtion isn't completey gone, I can still feel it at highway speeds, but nowhere near as bad as it used to be. Seems to be my vac-canister, which is very sensitive to even small differences in vacuum. I always set my ignition the same, 8° BTDC static and left the rest to the dizzy. But somehow that didn't do it. As soon as I have time I'll tune up my ignition properly.
I still have that vibration issue, but I don't think it will cause any further problems, it's just very slight. Somehow my bad ignition seems to have amplified the problem...
Thanks for all the help, I'll keep you posted as soon as I find the actual source of the vibration.
CU,
Mad