Cylinder head heat crossover?
 

Just to verify, the exhaust crossover can be plugged in head and intake gasket but cannot plug passage in intake manifold. Correct?

Re: Cylinder head heat crossover?
 

Read the rule several times. Says I can block on intake side of head. The rest of rules in head section and in intake section does not address plugging crossover in intake passage. I'm asking as I used lead to plug intake side on head. Pulled intake today because of having it be so hot along with carb and losing .2 ET. and found all the lead is gone from head. Yes it's gone with exception of a small nugget.
Want to plug at intake as I have no intention of pulling heads off.
I can make a plate to cover holes at intake surface, but dont know if its enough.

Re: Cylinder head heat crossover?
 

Jeff, some gasket sets come with the metal plate to block off the heat crossover. Tried the old Coke/Beer can cut up, burned right through. The cans are too thin now days.
Couldn't find a metal block off for my engine so I found a couple in my tool box from a Chebby that worked with a little modification. Never had a problem with them...yet.

Saw these gaskets that are already blocked.
https://www.summitracing.com/parts/s...ake/oldsmobile

Kelly

Re: Cylinder head heat crossover?
 

Thank you. But on Olds they have a steel valley pan/ intake gasket all in one
I might trim the steel valley pan to allow for these gaskets to work. That might be the ticket.
Also I was going to use stainless steel for blocking.

Re: Cylinder head heat crossover?
 

A little lead is good for it. LOL
I can't remember if there are 1 or 2 exh. passages up to the intake side, but you want them completely filled and separated so the headers scavenge correctly. I've done many, many sets that are out there, using molten aluminum.
Also you want to mill the exh . side until the center ports are completely divided. Either that, or build up a dam on you header flanges.

Re: Cylinder head heat crossover?
 

4 suggestions

1-Edelbrock #2733 plug ---about $12
2-Mondello #HR-351 insert---about $25
3- fill the cavity with liquid aluminum or maybe try JB weld
4- fabricate an aluminum plate to fit between the gasket and the cylinder head might have to resurface the manifold to compensate for the space

FED 387

Re: Cylinder head heat crossover?
 

Thank you. I think the stainless insert will be the way..

Re: Cylinder head heat crossover?
 

I don't know that you can't block the intake, if they let you fill the head all the way down to the port.
You could take a chunk of 1/4 " aluminum or steel and make a plug with tapered sides, and bang it in there.
No bubble packs here, unless we have to.

Re: Cylinder head heat crossover?
 

2020 Rule book: Stock Cars

Cylinder Heads
“Heat riser passage may be blocked from intake manifold side of cylinder head. Blocking passage down in the valve pocket prohibited.”

My interpretation: don’t block anywhere down into the head, but that’s just me. I would hate to get busted for plugging the head when a thin piece of stainless will be sufficient.

Kelly

Re: Cylinder head heat crossover?
 

Kelly, As long as the plug is recessed a tad and not reshaping the port, it's fine. We've been doing them that way for year....Hettler /Kadar/ Watters , and others.

Re: Cylinder head heat crossover?
 

hi, I found .015 stainless sheet works excellent. used same ones for last 10 years, has never burned out or blew a hole through it. mine are 2" by 2 1/2 "just food for thought.

Re: Cylinder head heat crossover?
 

On my 390/427/428 FE Fords, I have always blocked the exhaust crossover opening in the intake gaskets with a piece of an old butter knife, trimmed to fit inside the slot in the gasket. I have tried the gaskets with the unopened crossover holes, but they always burnt thru in short order. I always found it interesting that NHRA will not allow you to fill the head passage down into the bowl, yet the approved Edelbrock heads have no provisions for the crossover passages at all, but thats OK.

Re: Cylinder head heat crossover?
 

NHRA will allow you to fill the passage as long as it does not extend into the bowl and make an extension of the port ceiling surface. I used Plaster of Paris poured into the crossover passage to within about 1/2" of the port. Usually wadded up tissue stuffed into the passage from the port side served as the boundary. Once it was heated, it was like ceramic. Never had a problem.

Re: Cylinder head heat crossover?
 

I have always used zinc...that's what Mondello sold....
I buy a ingot of zinc alloy from Mc Master Carr industrial supply it is about 12'' long 3'' wide and 2'' thick will do 2-3 sets of SBC.
Olds might get 2 sets out it..
next set I do I may melt down some old pistons since I accumulate about 6-8 55 gallon drums a year that I scrap...
I have blocked off a SBC intake.. I filled all the heat riser and EGR passages...
intake was cracked under carb so I filled it to prevent vacuum leaks to EGR passages and it has been through teardown....
I think filling head is better to keep heat out of heads

Re: Cylinder head heat crossover?
 

Mike, A machine shop that I did business with did just that. They were a low buck shop. They used a Colemen camp stove to heat a cast-iron skillet and melted down the old cast pistons. I know they did this in some Oldsmobile heads and maybe even some Cleveland heads. Also in early December, they sold 4 to 5 barrels full of old cast pistons to a scrapper. The money earned would pay to throw a Shop Christmas party. I miss the shop, lots of Good Times.

Re: Cylinder head heat crossover?
 

"No bubble packs here"



I could of sworn that was you standing in the window waiting for the UPS truck intently LOL

Re: Cylinder head heat crossover?
 

On applications that can use sheetmetal to block the crossover, I've had good luck with aluminum (thicker than cans) if glued & coated on the inside with a good hi-temp silicone to help insulate it.

Re: Cylinder head heat crossover?
 

I have bought a new set of slicks past 4 years and bought my Hans device a few years ago with my scrap money...I have a 02 S-10 and a 4'X8' single axle trailer I haul it on.. I have pulled on the scales @10,400lbs before,the 10 and trailer weigh about 4200lbs....
the scrap yard is only about 3-4 miles away and I go about 25-35 mph and I have been nervous if I would make it there...

Re: Cylinder head heat crossover?
 

There can be money in scrap. Be careful!