65 SF 383 Heat riser issues... A lot of condensation all over it

James Romano

Well-Known Member
Joined
Sep 28, 2019
Messages
563
Reaction score
446
Location
Long Island, NY
So I've been doing a ton of work all around the motor, but not Ion it. All was good when I parked it for the winter and to start working on it. I decided to run her today and do some leak checks.

Right away, I began notice steam coming from the heat riser and exhaust coupling, on both sides. I let it run for a while, she got up to temp good, motor sounds great...but a ton of steam from that spot. Water everywhere. Not from the motor, but that heat riser.

What do you guys suggest. I can't tell if it's closed or open. Feels loose, but very quiet, meaning no valve slap. Can I take off the manifold and just remove the thing?

Thanks
 
A certain amount of steam on an engine that has been siting for a while is normal. Condensate being evaporated off the manifold and heat riser. As long as the steam is on the outside of the manifold you do not have a problem. If the coupling is leaking steam, you have an exhaust leak, probably from a bad flange gasket on the heat riser or a degraded bell connector on the exhaust pipe, check to be sure the bolts are all tight.. All gasoline engines product some steam until they warm up, that is normal. If the engine still produces steam after it is at operating temperature, you likely have a coolant leak into the combustion area and that is usually going to be a cracked head or a bad head gasket, and that needs to be repaired asap or engine damage will result. I would suggest getting a hydrocarbon detector from you local auto parts and running a hydrocarbon test on the cooling system, they will usually loan or rent them for minimal cost. If the cooling system tests positive for hydrocarbons, there is a coolant leak into the engine.

The heat riser needs to be left in place if the stock carb is still in use. The heat riser provides exhaust gas to heat the thermal spring that releases the automatic choke. If you remove the heat riser, the choke can not function properly and the engine will likely run rich. If you have replaced the factory carb with an after market unit that uses a mechanical or electric choke, you do not need the heat riser and it can be removed.

Dave
 
Ok. I'll see if anyone has one locally. I'm running a mix of distilled water and antifreeze.

Its definitely producing a lot of water in that area on both sides. I didnt have the issue when I parked the car 2 months ago. We've had some cold weather the past few days, but nothing this car hasn't seen before.

Not sure why it's suddenly doing this
 
It doesn't smell like burned water from the motor, it smells like someone pouring water on hot metal.

Oil is clean, I drained it before running the motor and it was normal. No oil in the coolant either.
 
It doesn't smell like burned water from the motor, it smells like someone pouring water on hot metal.

Oil is clean, I drained it before running the motor and it was normal. No oil in the coolant either.

That is a good sign, but I would still check for hydrocarbons, cheap insurance.

Dave
 
I will... Mainly because my heart dropped into my stomache when you said cracked head... I don't need that kind of a headache right now
 
Went under the car today to clean a few things up and noticed a puddle of oil... Looked up and found this.

I can't tell if it's a blown gasket or hear from the exhaust blasting on the side. Also noticed my exhaust manifold is wet from oil soaking.

Before I tear into taking off the exhaust manifold, any thoughts on this by anyone. I'm by far no expert, but it looks like I need to buy some gaskets.

IMG_20200112_143800528.jpg
 
Exhaust leak is because one of the retaining bolts is missing the nut and has probably blown out the gasket (Note grey exhaust stain on engine block). Heat riser is missing some parts, spring for the butterfly it appears, so the heat riser is not likely working either. Oil leak is from the valve cover and oil is running down the side of the engine. Replace the valve cover gaskets. Also check the oil pressure sending unit for leaks and report back.

Dave
 
Oh man... Dave I'm sorry. That was me taking apart the exhaust pipe. I forgot to mention that.

I took off the exhaust manifold as I figured I was there and I know these don't have gaskets...or should they?

Looks like you said, the valve covers are leaking. I've got oil on everything. Looking at the manifold to exhaust flange looks rough as well. Like he tried to make it work. The middle exhaust manifold stud nuts were super loose and had no torque on them. Jeeze .. laundry list of crap.

I have an idea for the flap, to safety wire in open position.

Can I get away with loosening the two bolts holding the heat shield So I can remove it? Or would that really create head issue?

IMG_20200112_154458603.jpg


IMG_20200112_154506129.jpg
 
Mopar B and RB series engines do not use manifold gaskets as they are a precision fit. The heat shields should be left in place, they protect the spark plugs and the wires from degrading from excessive heat. Loosening or taking out head bolts runs the risk of breaking the seal between the head gasket, head and block. If you are still running a stock carb, the choke will not function properly if the heat riser is blocked open. If you have a manual or electric choke installed you can get rid of the heat riser altogether. There are rebuild kits available if you need to repair the heat riser.

Dave
 
I don't want to start any arguments, but I'll respectfully disagree that removing the heat riser doesn't allow the factory choke to function properly.

Let me qualify that. If you drive the car a lot in cooler (50 degrees or less) weather you may have to make some adjustments. Your choke stove also has to be in good condition and the intake manifold heat passages have to be clear.

Further, if the riser is working and needs a spring, those are available. Mine was stuck partially open. My exhaust guy removed what was needed to clear the restriction.

Today I started the Polara today in 41 degree weather and the choke worked perfectly. It doesn't have a heat riser.
 
Last edited:
Back
Top