302 build up

[Simon]

trying to put together a 302. put in crank and pistons, but as I tighten the rod bolts the crank gets MUCH too tight. The clearances are ok, where am I going wrong?

Simon

 

[Jason Lycett]

Hi Simon

I had a that same problem when i built mine some time ago. I found one of the conrod's was out of round.

Try checking that

 

[Randy V]

One of the following;

If you've already checked the clearances with a micrometer on both the crank pin as well as the assembled rod - I think you better check to make sure that the rods were installed correctly on the piston - or - that you're installing the piston/rod assembly into the correct hole with the correct orientation.
Hint:
The chamfer on the big end of the rods needs to point to the outside and not towards the neighboring rod. This chamfer corresponds to the chamfer cut into the side of the crank pin.

 

[Simon]

OK, thanks chaps, sorted it now. I had the very last rod cap on back to front. Don't think any damage was done. Turned it round and all torqued up now, everything seems nice and smooth...phew!
Thanks Randy you wuz right!

 

[Jonathan Strain]

Make sure you have not put a rod in the wrong place or turned a rod or its cap backwards.

 

[Doug S.]

I had a similar problem with a SB Chebbie one time, but all I did was take out the crank, left the rods/pistons in the block, and replaced the rod/main bearings. Put it back together and it was WAY too tight. I checked all the clearances, and they were OK. Finally figured out I had bent the crank--I had been stupid enough to stand it up on it's rear flange and it fell over. It never dawned on me that would bend it, but it did, and it was useless (as are, I am now convinced, all Chebbie products).

Glad it worked out better for you!

Dugly

 

[Wayne M.]

Since it is a rod, I would check the rod end for being round. A main bearing doing that could mean a bent crank or bearing alignment.