y-block problem

i got a problem with a y-block...we got in a 54 ford truck at work and it backfires pretty bad its really soft at idle and then when you get on it it gets really loud...its pretty steady in its timing when it backfires...its also heating up on the center intake runner...the rest of the intake can be cool but you cant touch the center runner...the timing on the truck is good...were all a bit puzzled...i was thinking sticking valve

 

pull the valve covers and see if all the pushrods are good.

 

Bad power valve? Spark arrestor?

 

My guess is a leaky intake manifold!

 

hung intake valve on the hot runner, pull the valve covers and do some investigating

 

That runner in the center isn't an intake runner. If I'm picturing it correctly, the intake runners are stacked and make 4 "legs" that hold it up over the valley pan. The thing in the center is just a hold down, I think. There might be an exhaust tube in there to warm up the carb which may be why it's so hot.

When was the last tune up? Take a look at the points.

 

The runner in the centre is a heat riser for the carb, check your timing .

 

Check the pushrods or possibly a bad intake valve.

 

Look for an extreme lean condition, but I'd say that you have a burned valve. If it backfires in the carb, its an intake valve and the opposite for the exhaust. Do a compression check first. A vacuum gage can indicate a burned valve condition as well.

Bob

 

Time to open the valve covers and look at valve action. Could be worn cam lobes or posible broken valve spring. Fix it, it is a great engine when the oil is getting where needed.

 

We had a stuck Intake valve that was popping thru the carb on the 292. When we pulled the valve cover the pushrod had fallen into the valley. Tapped the valve with a rubber hammer and it popped closed. Lubed it up with some trans fluid and worked it up and down for a bit. It's been fine ever since.

 

Yeah, pull the valve covers first, it just may be hung up and not burned yet.

Bob

 

I guess I'll repeat all the previous stuff;
- the center "runner" is the exhaust crossover
- if you've done a recent tune up, recheck the wires for the correct firing order
- run a compression check
- check in the valve covers

Good luck

 

I go with check to see if the wires go to the correct plug, I have mixed them up before and got the same results as you are getting.

 

ok, so what was it?

 

well it was a broken push rod, but an exhaust one...anyway we got the valve train pulled and the rocker arm piviot was installed wrong and there wasnt any oil getting to the rocker arms...the cupped end of the push rod is actually jammed on the end of the adjuster bolt on the rocker arm...the was a pile of metal shavings there too i think it was so hot that it welded the end of the pushrod to the rocker arm...at any rate itll be fixed monday