Customs looking for advice /help with 292 y block ford

have a 61 galaxie with a 292 y block , one side exhaust is running cold , about 1/5 the heat and pressure of the other exhaust pipe , engine is running well and firing on all eight cylinders,
have checked the muffler for blockages , not blocked.
have checked valve clearances , all ok .
checked timing .
have done a compression test to check for blown head gasket , all cylinders between 115 and 125 .
checked for inlet manifold leaks , no leakage found .
fitted new plugs , leads, cap and rotor .
anyone had any experience with this, or any advice on what else the problem could be .
thanks in advance

 

Did you check the heat riser valve on the (usually) passenger side exhaust, right below the manifold? Sounds like it might be stuck closed.

 

yes . heat riser valve has been removed as was leaking

 

Does it seem to have ample power? I'm assuming it is stock with a 2 bbl carb.

 

Stock intake?

 

4 bbl carb , holley 600 . i am assuming a stock intake , and seems to have ample power for for a 292 and 2 stage auto , have checked intake by spraying starter fluid around gaskets and carb base , seems to have no leaks ,

 

Only advice I have is to get yourself an laser thermometer and check over each port in the manifolds to gather some real info. Might find a cylinder problem or not, but having the data can't be bad.

One more thing, the exhaust crossover in the heads or intake may be blocked, cracked, burned open or something.

 

maybe something to look at , i think a lot of people for some reason block off the exhaust crossover , how would that effect the presssure and heat one one side of the exhaust , thanks

 

Just to clarify, you say that you checked the muffler ( as in singular) for blockage , is this one of those 1 inlet 2 outlet jobs or do you have a true dual exhaust, h pipe, x pipe? nobody is immune to a brain fart but without a full understanding of your exhaust system we’re throwing darts over our shoulder

 

2 separate pipes , 2 separate mufflers , straight from exaust manifolds to the rear ,no crossover pipe , only weak on the passenger side and have checked with muffler removed , still weak on that side

 

Ok well that’s bizarre then, what exhaust manifolds are you using? Have you had the intake manifold off, should be able to tell if the exhaust riser is open by the paint being burnt off the intake in that area, can’t see an exhaust manifold being so restrictive that the flow would choose to cross over.

 

Have you checked the head casting numbers, two different heads? Just spitballing here, mine has different heads same numbers, ones Cleveland the other São Paulo, even the casting lines are different.

 

will check heads , not sure how to , but will figure that out , heat riser on the manifold has been removed as was leaking arround the shaft . pluged holes and welded them in ,so no restriction there . would not think the exhaust manifold would be blocked , maybe the crossover , but should still exit out the exhaust on that side

 

The intake should equalise things out but seeing as you seem to have tried everything else see whether your carb is only idling on one side. Screw one mixture screw in and see what happens then try the same with the other.

 

at 5:59 you say, "no crossover" at 11:03 you say "maybe the crossover"

 

did think of that . took the carb off and turned it arround to check , still weak on the same side even with the carb mounted backwards

 

no crossover in the exhaust pipes , but crossover in the inlet manifold

 

You’ve not for some weird reason got a crossover valve in the exhaust at the end of the manifold as well as the one in the intake?

 

a heat riser valve on the manifold , which has been removed . and the inlet manifold has a heat crossover were the exhaust heats the inlet manifold/carb

 

Maybe the problem is on the hot side

 

Ok, so it’s running and driving ok? Not just idling, driving at speed, even 30 mph.

I’d get an infrared thermometer (cheap enough on Amazon) and start at the exhaust ports on the manifolds. Then both manifold/head pipe connections. Check the temperature at the back of the heads, temp gauge sender on the drivers side, and the soft plug under the distributor. Then the head/intake water passage on the manifolds, side of the thermometer housing.

Don’t be surprised if the water temp varies some, or the exhaust ports. But they should be close. I’m having a problem figure out what’s going on given it’s driving ok. Got to be a cold spot somewhere.

 

What kind of manifold readings are you getting? High, steady readings at idle? Fluctuating readings at steady cruising speeds?

https://m.roadkillcustoms.com/diagnose-common-engine-problems-vacuum-gauge/

If you don't have a vacuum gauge, borrow or better yet buy one. Very helpful diagnostic and tuning tool.