New One on me

[Katz427]

I have been assembling a 427, with a BBM block,  block is 5 years old but never assembled.  I have things mocked up, camshaft installed,  turns smoothly. Waiting on pushrods. I installed the distributor, (Mallory, that ran recently in a 390), and the distributor went in, however the camshaft is locked up tight. Can't turn it. Pulled the distributor out, camshaft turns smoothly. Took off the cam thrust plate, removed intake manifold, and the distributor does "seat" where the counter bore is but, then again the camshaft will not turn. It appears that the teeth are engaged too deep, from what I see. Anyone have this problem?

[blykins]

Which front cam bearing did you use?

[Katz427]

Hi Brent, the narrow one, followed your advice. That seems fine, 0.005 end play.

[Katz427]

I can't turn the camshaft,  but some paint on distributor gear  shows the camshaft gear making contact with the "root" of the distributor gear. The distributors available  to me, one is a electronic with a hardened ( melonized) gear, the Mallory has whatever came from the factory, ( dual point).

[blykins]

Both distributors do the same thing?

[Katz427]

Yes Brent, though the old Mallory, fits a bit better, going into the block. However, camshaft  will not budge, with either installed.

[blykins]

Is the timing set on?  You just have the cam in the block with the thrust plate on and the distributor in it?

[Katz427]

Yes Brent ,I removed the timing set, checked camshaft end play,  again, then tried the distributors again with no luck. Won't turn.

[blykins]

With the distributor seated, can you pull up on the rotor/is there end play in the distributor?

If not, then we need to start looking at dimensions on machined parts.  I’ve got a couple of BBM blocks here that I can compare with if need be.

[Katz427]

No end play when distributor seated in block. Everything is up tight, no camshaft end play either. It does seem, that the bore for the distributor,  perhaps might be off a bit (a tolerance stack up). I did see one forum where someone was saying their aftermarket FE block was off, with the bore for the distributor. Don't know , other than his comment was he "hand dressed" a bronze distributor gear, to get around the problem. Brent,THANKS for your help!

[blykins]

You could shim the distributor up a hair id think.  The distributor seal can be a little forgiving. 

Aftermarket blocks are fun.  Wait until you prime the oil pump and oil starts coming out of random places on the outside of the block.

[Katz427]

It seems that the gear on the camshaft, the teeth are maybe too thick, compared to an older Engle camshaft I have here. I don't know if there is anything that can be done, to correct this. I did see a post on Yellow bullet  where a gent with an Olds engine had a similar problem, the cam was replaced, and problem solved. Yes, I hope, that this block doesn't leak, it was pressure tested, but that was water jackets. Thanks for the feedback.

[DuckRyder]

I was going to say earlier, you got another cam you can install to test?

[Katz427]

Further investigation finds that the "hole" for the distributor is off about .016" to the front of the block ,and .005" closer to the camshaft. Finally I installed the whole shibang, into a NOS 428 block, and everything turns "smoothly". So in final analysis it is the block distributor hole that is off enough so that this right angle drive locks up. I'm not sure this is fixable. With a crank trigger ignition, and a Avaid belt drive outside pump it could be useable.

[CaptCobrajet]

A problem like you describe is fixable.  It could be bored bigger at the correct location, and the distributor hole and pilot sleeved to correct it.  Never seen that before.