Engine: Rebuilt 259 runs great - exhaust volume of rt dual is much less than left side

[LarkPhil]

Hi all,
My rebuilt 259 (Block and heads) with Edelbrock 1403 in a 60' lark Convert has less than 150 miles on it. It runs really nice, lots of power, but I noticed that the exhaust on the right side has a lot less volume coming out than the left and seems to be cooler. It has new 2" custom exhausts with 14" Magnaflows. They're not entirely broken in, but already sound great. The manifolds were cleaned and there are no kinks in the exhaust pipes.When shooting the engine with a temp gun, both sides appear to be about the same. Should I be concerned and keep investigating or is this no big deal. I've always thought they should be the same if both sides are working well.

Any thoughts are appreciated

Phil

[altair]

engine exhaust

Hi all,
My rebuilt 259 (Block and heads) with Edelbrock 1403 in a 60' lark Convert has less than 150 miles on it. It runs really nice, lots of power, but I noticed that the exhaust on the right side has a lot less volume coming out than the left and seems to be cooler. It has new 2" custom exhausts with 14" Magnaflows. They're not entirely broken in, but already sound great. The manifolds were cleaned and there are no kinks in the exhaust pipes.When shooting the engine with a temp gun, both sides appear to be about the same. Should I be concerned and keep investigating or is this no big deal. I've always thought they should be the same if both sides are working well.

Any thoughts are appreciated

Phil

Check your heat riser, it is on the right side and if stuck closed it will force the exhaust over to the left side. David

[sals54]

Yeah, like altair said, sounds like the heat riser. Check to see if its free, or if its stuck in the closed or semi closed position.
If thats not it, take a good look at your entire exhaust system to see if you got it pinched or crushed anywhere during the rebuild process.
Then, if its not that, check your mufflers for flow.
Good luck

[LarkPhil]

Thanks for the suggestions...I'll check them out.

[PackardV8]

If it's not the heat riser, the next steps I'd take would be:

1. Re-torque the heads.
2. Re-set the valve clearances
3. Run a compression test. All cylinders should be within 10% of each other.

Let us know what you find.

jack vines

[Studebaker1962]

Yes, Heat riser is stuck. I had the same. Mine was 75% closed with exact exhaust difference you noted. I live in hot Florida so I bought a machined spacer to take its place. So I don't need the riser.

Soaked the studs in PB Blaster for a week and still broke both. I was able to grab the exposed stud that had a little length showing. With the help of a welding torch to heat it I was able to get that one out. Great because that was the stud in the blind hole of the header. Not so lucky on the in-board (block side) stud. But it is not a blind hole and I drilled through and added a bolt and nut.

1962 GT Hawk 289.

Good luck!!

Jim

[sals54]

If you find it to be the heat riser, remove it, have the shaft ends welded with the baffle removed. These are notorious for seizing. With the limited driving our cars get these days, its too big of a pain in the neck to even deal with. But then again, I'm speaking to this from California. So, perhaps my opinion on this matter is skewed a bit. I haven't had a heat riser on any of my cars for the last 40 years.

[Studebaker1962]

I heard the housing crumbles your hand when removed. Mine did. Machined spaced and 2 gaskets from Dave Thieabault.

Only downside with removing the riser is that now you hot exhaust under the carb in the intake manifold all the time and run the risk of boiling the fuel in the carb bowl. I live in a Florida don't belive I need the crossover. If I continue to sputter and die I have heard you can remove the intake manifold and either ram it solid with aluminum foil balls or have both sides welded shut. Risk here is that you might break a bolt off in the head.

Jim

[sals54]

Hey Jim. Removing the heat riser will have no effect on how much heat moves through the intake manifold while hot. Once hot, the heat riser will remain open anyway, which allows for more heat to pass through the exhaust pipes. While the heat riser is closed, (engine cold), more heat is pushed through the intake manifold to help it warm up faster in cold temperatures. Not many of us are driving our cars in extremely cold weather anymore.
And please don't put any aluminum foil in your manifold. You'll regret it fer sher.

[Studebaker1962]

Yes I was dubious about the tin foil.

I am running 92 octane ethanol free gas which boils at a lower temp's than fuels from yesteryear. I am going simple first (there is an old extensive thread I started months ago about vapor lock). I added a pint of lead additive in an attempt to raise the boiling point. I have so heard to add a pint of diesel to every 10 gallons to raise the boiling point.

Non the less the posters problem of exhaust flow and temperature points to the heat riser being stuck. Mine was with same symptoms.

In problem solving go for simple first.

Jim

You correct that I did not think thru that with the butterfly open it is same-same as not having one...oops