Distributor Position - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

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post #1 of 6 (permalink) Old Jun 23rd, 01, 04:48 PM Thread Starter
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Join Date: Jul 1999
Location: Broomfield, Colorado
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Bill -

This is a follow up to my post "Distributor/Oil Pump Rod" (https://www.camaros.net/forum/Forum9/HTML/003576.html). Before I take any irreversible action I'd like to run this by you and get your take on it.

The short version is that I seem to have only 3/16" of engagement between the key in the distributor gear and the oil pump rod slot. Also, only about the lower third of my distributor gear appears to be engaging with the cam gear. (same situation with either my old Unilite or new MSD 8361 distributor)

I don't know if the amount of engagement of the gear and pump driver key are correct. The key in my "old" distributor sheared off and quit turning the oil pump which is what got me looking at all this closely.

I had my block decked .023 but not the manifold. Is that enough to cause this problem?

Am I over analyzing this? Are the measurements and gear contact OK? If not, what's the best way to correct it. Do I have the manifold machined?

As always - thanks for the advice!


[This message has been edited by RockyMtnRacer (edited 06-23-2001).]
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post #2 of 6 (permalink) Old Jun 24th, 01, 06:09 AM Thread Starter
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Location: Broomfield, Colorado
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Bill -

I think maybe I've got this figured out. I found a reference in one of my engine building books to the oil pump rod and intake manifold specs.

It says that when installed the pump rod should have between .010 and .040 free play lengthwise. My setup gives me 5/16" or .3125 free play.

Secondly, it specifies clearance between the manifold and lifter valley rail at between .060 and .120. Mine is probably closer to a fat 3/16" (.185+).

If I have the manifold machined to reduce the end clearance to approx. .060 I still end up with .185 pump rod free play. About .050 (est.) of this can be attributed to the baffle I just remembered I installed between the oil pump and the rear cap. If I could eliminate this additional amount I'd be right where I need to be.

The best way in my mind to get that last .050 is to take it from the machined pad the distributor seats against.

Do you agree or am I still missing something?

'69 400SB, Richmond 5-speed
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post #3 of 6 (permalink) Old Jun 24th, 01, 09:28 AM
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Join Date: Apr 2001
Location: Houston,TX
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MSD makes a distributor with a slidding adjustable collar. That might be what you need to get it just right without all the grinding.
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post #4 of 6 (permalink) Old Jun 24th, 01, 11:00 AM
Join Date: Aug 1998
Location: Waldorf Md. USA
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We have milled a lot of blocks and heads and never have had a problem with the distributor not going down properly. I would say that if you got the manifold bolted on ok, then it should not be up that far.
I have two distributors sitting at the shop that I can look at on Monday morning. I will take a look to see what type of wear there is on the gear and where the oil pump shaft fits in.
Send me a reminder e-mail either late tonight, or early Monday so I will get it at the shop instead of here at home.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md
1971 Chevelle "Heavy Chevy" original owner
1973 Z-28 ..one family car...Brother bought it new in 73
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post #5 of 6 (permalink) Old Jun 25th, 01, 06:13 PM Thread Starter
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I dis-assembled my new MSD dstributor, had the collar milled off today, and re-installed it with an adjustable collar. It dropped right into place with full engagement to the oil pump rod and good gear alignment. I set the collar and tightened it down and all is well. Kind of the hard way around but it will work great.

'69 400SB, Richmond 5-speed
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post #6 of 6 (permalink) Old Jun 27th, 01, 10:24 AM
David Pozzi
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Join Date: Nov 1999
Location: Central California, USA
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Man, I thought I was the only one who had wierd things like this happen.
Sounds like you found a good solution.
watch the corner manifold bolt holes. Remove a couple of bolts and look in there to see how the manifold sits.
Usually, the corner bolts are smaller hole size and center the manifold on the engine. If there is not a little bit of clearance on the corner holes, the manifold can be held up a bit, hanging on the bolts, and you can have sealing problems with the intake gaskets. This could hold the intake up a bit too.

Check my web page for First Gen Camaro suspension info:
David's Motorsports page
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