I have a problem. My 383 was being put together today and the builder ran into an issue with the rods hitting my camshaft. Rods are Eagle (part number SIR6000BBLW) and the camshaft is a Lingenfelter 211/219 (part number 74211). I thought the rods were clearanced from Eagle so that I would not have to run a small base circle camshaft.

Would it be best to take it to the machine shop and have them remove the rotating assembly to grind the rods and rebalance it? Or, should I just purchase a small base circle camshaft? I bought the camshaft from Lingenfelter about 4 months ago so I really don't think they would allow me to return it. What would be the safest way?

 

I would not have used those rods to begin with, I don't like eagle products and a Scat Pro-I beam would have been a better choice with no clearance issues.

At this point you can either clearance the rods and rebalance, or buy the Scat's and re-balance...or IMO you should buy a bigger cam on a small base circle - that cam is itty-bitty for a 383

 

Grinding a little off the rod bolts will not require rebalancing. I agree with M1 about the rods.

Rich

 

The rods need clearanced not the bolts.

 

The SIR I-beams are not the strongest rods around, so even though the 211/219 is tiny for a 383 I would stay on the smaller range for the cams anyway. Too much power for the parts used will lead to an early rebuild...

It seems that the cheapest way to get it up and running would be to take the hit and sell off the LPE cam, and have a slightly more agressive small base circle cam ground for you.

Good luck.

 

Same principle, it will not need rebalancing.

Rich

 

The Scat rods may have been a better choice but I have the Eagle now. I probably should have chosen the Scat's but there are many people who have had great sucess with Eagle products.

A larger camshaft would make more power but I am not looking to build a race car. I just want a very nice daily driver that has great torque for the street. I chose this camshaft based off another member by the name of ABA383 who used this same camshaft in his 383 that was built by Lingenfelter. It may not have been the fastest thing on the road but he felt that it was a great daily driver and he was very satisfied. I think he drove on the set-up for approximately 12+ years.

So, the most economical way to handle this is to purchase another camshaft?
How expensive would it be to have the rods ground down and the assembly rebalanced?
Thanks for the responses gentlemen.

 

How do I know what size base circle to get? What is acceptable clearance between the cam and rods?

 

As I said, it is NOT going to need rebalancing. Taking a few grams off is much less significant than adding weight.

Rich

 

I'm wondering if: even with a small base-circle camshaft that the rods might still hit the cam. It's possible don't you think?
The shape of those rods have so much big-end shoulder sticking up.
If it were my motor I'd just have the spot on the rod machined down and not do a rebalance.
Karl Ellwein

 

You are right, there will still be a possibility of a small base circle cam interfering with the rods. I think I am going to have the rods machined down.

I know the camshaft is not desired by most but I was trying to copy ABA383's build. I figured it would make a excellent street car while maintaining great drivability.

 

If going custom, definitely inform the cam designer of what rotating assembly you are using.
He should be able to get you exactly what you need without a problem.

It seems like you need a more aggressive cam, that is the route I would go.
Depending on who is assembling your shortblock, machining the rods may or may not be a cheaper route.

FWIW, I'm running 6" Eagle forged rods and a custom cam from Bret Bauer and did not have any issues.
I think the rods you are using have a little more material though, it will likely require a little more planning.

 

Is there any disadvantage to machining the rods? Will this affect the longvity of the block?

 

I dout machining the rods have any thing to do with the longvity of the block. However, id get another opinion besides mine.

 

My Eagle Sir rods hit the cam the same as yours. My builder just ground them just enough for the cam to clear. No re-balance, no issues.

Run the cam you want. Only you know whats best for you.