I purchased a long block 292 from S&J Engines out of Spokane WA. In my earlier threads I was having problems with the timing, which is now fixed. The valve lash, which is not fixed. And the Carburetor, which was spraying fuel out the top, and it is now fixed.

Today, started the truck and it purred like a kitten. I was bringing it up to temp, my thermo gauge showed 161 degrees, when I heard a ping, ping. I also had a vacuum gauge on it was stead as a rock until the ping ping. I quickly shut the engine down checked the temp of everything and the driver's side head was over 500 degrees, the passenger side was only 215.

I waited for everything to cool down and then I pulled the valve covers off and the exhaust valve on number 8 was stuck open. I was able to free the valve but now I'm scared to start the engine again. I also noticed that the intake manifold between number 6 and 7 cylinders is a dark brown, my paint job is now ruined on that side and the driver's side valve cover is scorched real bad too.

My idea is that the driver's side head is not getting cooled properly. Let me back up too, one of the other problems that I mentioned above was the engine wasn't idling right so I checked the valve lash again. When I got to the driver's side head number 5 and number 7 exhaust valves were stuck. I wasn't able to un-stick them so I had to remove the head and replaced those valves. But they seemed fine today after starting the engine. While I had the head off I cleaned all of the surfaces and blew all of passages out, to make sure I hadn't left some gasket pieces behind.

I'm wondering if the old intake manifold I have is just insufficient to cool the driver's side head - if that's case I'll just go buy a new Edelbrock intake manifold.

I'm also using the old headers that come up and the crossover is in front of the engine to the passenger side header, I'm wondering if those headers are just too hot and making the head too hot.

Any idea?

 

sounds like the cross over pipe heat riser valve is stuck closed

 

Thanks Kevin. Just so I'm understanding this the cross over pipe heat riser valve would be on the passenger side, right? I wonder if I may have it upside down? Can the truck run without the valve?

 

I would gut it, take out the flapper blade and leave the shaft to seal the holes.

But I struggle to see why #8 would be getting hottest, if the flapper is up front?

 

Yes at the front of the pass side manifold where the cross over bolts on


I never run them, they cause the paint to burn off the intake even when operating correctly,


I also block the 2 passages on the intake with thin sheet of stainless steel to totally prevent the exhaust gases from burning off the paint. I never drive my rigs in cold weather so it isn't needed for me.

 

To me it sounds like you had an air pocket in the hot head so there was no coolant and ultimately no cooling. Eight being at the rear would be the hottest which caused the valve to stick as everything expanded.

 

As to the sticking valves.....were the heads rebuilt? I'm thinking valve guide tolerances might be to tight. Is it getting oil to the top end? This can be a problem with Y's.

 

tinman 52 - yes the heads had been rebuilt by S&J Engines in Spokane. I was thinking that the valve guides might be too tight also. Yes, I primed the oil pump and there is very good oil delivery to the top end.

truckeemtnford - That could be a possibility, since I had to drain the coolant to remove the head and replace the #5 and #7 valves.

bigwin56f100 - I was really bummed about the headers I had used a really hot resistant paint on the headers. Now the headers are all grey and peeled not to mention my valve cover and the intake.

So I'm going to take the heat riser valve out take the flapper out but leave the shaft in put the heat riser back into the system and try that. Hopefully, I can get to that this weekend. Thanks for the suggestions!

 

Head gasket on wrong. Might look right but they go on wrong Large coolant flow needs to be toward the rear of the engine.

Head gaskets. The 2 head gaskets used on a Y-Block are identical. What is critical is that the open coolant holes are at the back of the head and the blocked portion of the gasket is at the front. Look for the word FRONT on the gasket and place it at the front even if it looks wrong. This places 1 of the gaskets face up and one face down.

 

Very good Ray, Also you can tell if they are on correct by looking at the front of the engine and on both head gaskets you will see the little tab sticking out between the head and block (if they are on correctly)

 

I would also say head gaskets but if they are OK... After rebuilding my 312 I put plain water in it till all testing was done. After testing I drained the water and poured in coolant. Left the radiator cap off and started engine to circulate and top off. After running fine for 5 min the engine started running rough and a large rush of steam came out the radiator. Valves stuck and push rods bent. The engine had developed a air pocket, gauge didn't even show hot till the thermostat finally opened and the air and steam escaped. My guess would be you had trapped air in that head.

 

AFAIK there is no paint on the market capable of resisting the heat on headers, they can easily reach 1300* F and more! The special ceramic powder coatings will withstand it, but it will be difficult/impossible to find any place willing to coat headers that have been painted/used. Best done on new headers and should be coated inside and out.

 

Bigwin56f100 and raytasch - I was extra careful about putting the gaskets on and front was front on both. Even so I still checked the water galleries to make sure everything matched up.

Rimrock F1 and truckeemtnford - I think you're right I had an air bubble back by #8 and that's why that valve stuck.

UPDATE - I gutted the heat riser valve and started the engine purred long enough for it to come up to temp and then a few minutes later I had another valve stick. This time it was #4 so I think I must have had an air bubble on that side too. I was able to loosen and get #4 exhaust working again and put everything back together. Started it up this time and she purred so nice and continued purring until I got the timing set, the idle set, and the air mixture set. It continued purring so I took the chassis out for a drive (just have the seat strapped onto the chassis) drive it around the yard and around the driveway. I'm happy camper!!!! Thanks guys!

 

Next time you change the thermostat drill a 1/8" hole in it to help bleed the air

 

This is what I did to the new thermostat I installed after the over heat, works great.