Ok we are putting our motor together we got the crank, rods, and pistons in. Now when we put in the cam and then try to rotate the crank it will hit the cam lobe at a certain point. Does anyone know what im doing wrong?

 

The crank hits the cam? That is very odd. Do you mean the big end of the rod is interfering with the cam?

rich

 

Its the two front lobes of the cam is hitting the towards the bottom of the rod.

 

This is not uncommon in a stroker, depending on the rods used. Two basic aproaches to solving it. Grinding the head of the rod bolt or installing a small base circle cam. FWIW, the best medium price rod for clearance is the Lunati Pro-Mod. the Oliver billets are the best in that respect any many others. Only problem with them is $$$. I have seen most of the other populatr rods need clearancing with a 383.

Rich

 

Yeah it is a stroker. I guess im going to try to grind them down. But it seems like i might have to do alot and that kinda scares me that i might screw it up.

 

You do have the timing chain on right?

 

Yes the timing chain is on.

 

Then grinding the rods or diff. cam is your only options.

 

I got my stroker kit from speed-o-motive. Maybe they will exchange the rods. If i grind it...wont it throw off the balancing?

 

Yes,and swapping rods will to.
A .930 base circle with most lifts will clear.A .900 will for sure if not over .430 lobe lift and get it made with a billet core.
The rods will hit #2 & #7 lobes.

 

Yeah its #2 and #7. We are going to try a smaller circle base cam. Brett is sending me that cam.

 

A.930 "should" clear,but I am not up to speed with all combos,just the ones I use for my customers.

 

Most times what should be done is that you fix the rods. This is a case where you are using Scat I beams, which almost always hit in a 383. I've thrown standard base cirlce cams (that had enough lobe lift) in 396's with no problems what so ever with the right rods.

If I had a choice on what I would do... I would clearance all the rods. Then again I test fit everything as the motor is built. Having a bigger base circle on the cam is going to add strength and stiffness to the cam which will improve the timing of the cam, that's more important than a few grams off a part of the rod that is not stressed.

On the balancing end of this.... 2gs of rod taken off every rod is hard to find. Balancing is basically a best guess calculation and once you introduce oil into the mix there is no telling what the real bobweight should be on the crank in dynamic conditions.

Some rods will have this problem... it's best to tell your head porter (in this case) or cam grinder what rods you are running. That will allow them to get you the right base circle.

Now there are Eagle Stroker clearanced rods for 4" strokes. They have the area above the rod bolt cut down more for more cam to rod clearance.... Good idea on a 383 or 396.

Bret