Hold down clamp

[Tom Goldman]

The MSD 7905 hold down clamp is the strongest Chevy type clamp I've found.
It's made for holding magneto's which are notoriously difficult to keep from moving.
I used to silicone the base gasket, but I've since machined an O-ring groove in the collar and it works great, no vacuume leaks and it's a lot easier to phase the distributer.

[Ron Gusack]

Thanks for all the replies, you guys are the best.

Dave, I used Ultra black. I just called it RTV because I'm a slow typist.

Lew, If I knew that clamp was deep enough to pressure the center of the collar, I'd buy it.

Jeff, I thought about putting another clamp on it, but I'm looking for an easy way out first.

Dana, My tube of Right Stuff was like a brick. been to long I guess.

Tom, I see that the 7905 uses a stud. This is leaking between the OD of the distributor housing and the ID of the collar and maybe some where the split is in the collar.

[Ed Wright]

Tom has the best answers.

[Ron Gusack]

Originally Posted by Tom Goldman

The MSD 7905 hold down clamp is the strongest Chevy type clamp I've found.
It's made for holding magneto's which are notoriously difficult to keep from moving.
I used to silicone the base gasket, but I've since machined an O-ring groove in the collar and it works great, no vacuume leaks and it's a lot easier to phase the distributer.

Rotor phasing isn't necessary unless the car has EFI or a crank trigger, right? I've only done that when I was running a crank trigger.

[Tom Goldman]

Originally Posted by Ron Gusack

Rotor phasing isn't necessary unless the car has EFI or a crank trigger, right? I've only done that when I was running a crank trigger.

Right, but with timing set by the distributer, silicone on the gasket does not make timing changes as easy as you would like.
The adjustable collars are a big vac leak source , but once you have your height established , scribe it , reinstall with silicone on the i.d and the split, and try it with a new gasket and a good clamp.....It's not a major machining opperation to install an o-ring groove to eliminate the gasket.
BTW , I've found one of the best sealers out there to be Mopar differential cover sealer and adheasive. It's grey in colour and it has tremendous adheasion.

[Glenn Briglio]

Originally Posted by Ron Gusack

Rotor phasing isn't necessary unless the car has EFI or a crank trigger, right? I've only done that when I was running a crank trigger.

Rotor phasing should always be checked and corrected no matter what ignition system is used.

[Ron Gusack]

Originally Posted by Glenn Briglio

Rotor phasing should always be checked and corrected no matter what ignition system is used.

I pulled the distributor out of it yesterday and I first lined up the rotor with number one on the cap. I noticed that the balancer was closer to 50 than it was to the 38 that the timing light reads with the engine running. I guess I need to get an adjustable rotor and a new cap.

[FED 387]

sounds like the dist might be of a tooth ??? might hafta move it back or forth to get it lined up properly--also acheck fore wear on the dist gear see if its worn --FED387

[Ron Gusack]

Originally Posted by FED 387

sounds like the dist might be of a tooth ??? might hafta move it back or forth to get it lined up properly--also acheck fore wear on the dist gear see if its worn --FED387

The timing was at 38 then I put the rotor in line with number 1 on the cap then I noticed how far off the balancer was.

[FED 387]

I'd then check the timing chain/gears-ya got the advance locked ???--with the engine running when you check the timing does the timing tend to retard ??? you hafta check it at above 3500 rpm so that all the slop and the torsional twist is outta the chain--- as the rpm goes up to say 6-7000 it is gonna retard so that is where yoou need to be checking it---static timing is gonna be close but not the same as a running engine