'51 Pontiac 8 heat riser stuck

[Andy J]

I'm currently restoring my '51 Chieftain and have encountered a problem.The heat riser,as I call it,is stuck open and won't budge.I've sprayed PB Blaster and Kroil on the shaft,inside and outside,twice daily for over a week.I tapped lightly on the shaft hoping to jar it loose,to no avail.Today I took it to a friend and heated it with a torch.He had a thin pair of vice grips that we were able to get on the shaft,but with vice grips and heat,the shaft is still frozen.

 

I know some of you fellows have had this problem,so I'm asking for any tricks or advice you may know to get this thing freed up.Any suggestions will be greatly appreciated.The engine has been completely rebuilt and I want this car to be right.

 

Thanks,Andy J

[Bloo]

On my 36 Pontiac, over a period of a couple of weeks I sprayed Mopar Rust Penetrant (a new name for heat riser solvent) on it and occasionally tapped lightly front/rear. Meanwhile I was driving the car. Mopar heat riser solvent is at least as good as Kroil cold, and really turns to magic if you can heat cycle the parts repeatedly and keep reapplying it. Exhaust nuts for instance just come off with no drama it they are on a running car and you can plan ahead 2 or 3 days and spray them repeatedly in-between the heat soaks from driving. Anyhow, it worked on my Pontiac heat riser.

 

I don't know if a 1951 Pontiac has bushings or not, but on any heat riser with bushings, there is going to be trouble if the bushings break loose from the manifold instead of the shaft. It will stick repeatedly, and the shaft and bushings will have to be removed completely order to fix it. If it has bushings be VERY careful about forcing anything.

 

Edited July 7, 2021 by Bloo (see edit history)

[Andy J]

Thanks for the advice,Bloo.I picked up a can of Mopar Rust Penetrant today and began to spray it on.It smells different from all the other penetrants I've used,so maybe this is the ticket.I'm tapping on the shaft with a brass hammer,also.I'll try heat,also.

 

I've read if the thing is stuck open the engine will be a little cold-natured until it warms up,so if I can't get it freed up I'll just live with it.Here in central Mississippi,it's toasty most of the year.Even in winter we don't have many very cold days.I'll let you know in a few days the result.

[Andy J]

Success!  I got it to move from side to side yesterday,but it wouldn't turn.KornKurt told me heat it and melt candle wax and let it soak up into the bushings.I did that last night but it still wouldn't turn.I went into my shop today and grabbed the counterweight and it turned it by hand and it was free.I don't know if the Mopar Rust Penetrant or the candle wax or a combination of the two worked but it is working great!I've been tinkering with that thing for nearly two weeks.

[Bloo]

Excellent! Glad you got it freed up.

[Kornkurt]

Hi Andy,  Glad you got it loose.  Be sure to get the manifold planed if it is not straight.  KK