I have a 454 with 10.5 comp I use 93 oct. but still get pinging unless I back the timing down to 30 will 2 gaskets help much? I have edelbrock aluminum heads with felpro #1027 gaskets, does felpro make thicker gaskets for alum. heads. Has anybody tried the 2 gaskets does it work? The cam is a comp xe274s I know I could with a bigger cam but I don't want to lose the low end. My cranking comp cold is 215#. Thanks Gary

 

Since you're willing to pull the heads to address the issue, you may want to try some porting work on the combustion chambers. This may add a slight bit of volume but also smoother chambers resist detonation better than as cast heads. This would be a "correct" way to do it and would yield additional power in itself besides being able to run a little more timing. I've heard of people using 2 head gaskets but sounds like a bad idea, possibly a very bad idea.

 

You buy thicker head gaskets. Check with Summit or Jegs. You can buy headgaskets from approzimately 15 thousands to 45 thousands. It would be a lot better than two gaskets I would think.

 

YOu won't "loose your lower end" with a bigger cam in 454ci, c'mon man, old wives tales.

The reason it's pinging right now is mismatched parts, cam too small for compression. Put in a bigger cam, problem solved

 

So do I go to the next bigger cam will that be enough?

 

You need to do some calculations and figure out your dynamic compression ratio. You want to get it down to 8:1 I bet you are over 8.5:1 with that cam.

"If" it were a small block and you were at 10.5:1 with that cam you are 8.5 DCR which will ping.

"If" it were a small block and you went up one cam you would be at 8.17DCR which should be OK on 93 octane

 

I agree with MotorHead about moving up a size on the cam. To your original question, yes you can run 2 head gaskets stacked together. Smokey Yunick says you can so I believe it.

 

if it runs good at 30 you are done.
why do u want more?
AZDoug's 427 makes best power with 20-24.

 

Maybe some other "older gearhead" will remember this better but I seem to remember that in the early '60s, 409's came with two head gaskets ( per cylinder head/deck surface ) from the factory. Peace,,,Moosie

 

Yup, one on the left and one on the right.

 

not exactly what I meant, but worth a giggle. Peace,,,Moosie

 

I guess I am just surprised you are getting pinging with aluminum heads, regardless of mis-matched cam. With iron heads, I can see it, but aluminum? Maybe I am just confused on how all the issues relate together.

Ralph.

 

I'm thinking that the timing mark on your crank is not calibrated correctly...and, thus, your timing is not where you think. Check TDC to know for sure. I agree that alum heads should not be pinging with 93 octane, your compression ratio, and proper timing.

 

 

I have the XS274S may be I will try the next bigger size XS282S, I do have domed pistons I also checked my timing mark and it is correct. I didn't think I would have pinging with the aluminum heads, I could just keep backing the timing till it stops but it seems doggy.

 

do NOT over adjust the base timing!
limit the advance by weight travel:
stop pin & curve(stronger springs)
it will not be doggy if tuned right
will fry tires & not ping

 

I've read old smokeys books. The only problem with them is he was leading the pack in the engine field nearly 40 years ago. He was locked into that days technology. He would have to be retrained to even work at a modern race engine shop.

Two head gaskets would be so weak. I'm replacing a quality head gasket without the overpressure of one detonation.

I've built two motors with to small of cams and had to lower my dynamic compression ratio. bigger cam doesn't mean radical idle if you put some thought into it. Don't use or trust some $8 per "Techy" at CC.

Before I would tear everything apart maybe try retarding the cam 4 degrees.

"Read" your spark plugs. The wrong heat range plug can cause detonation as well as preignition. If the insulators around the electrodes on your plugs appear yellowish or blistered, they may be too hot for the application. Try the next heat range colder spark plug. Copper core spark plugs generally have a broader heat range than ordinary plugs, which lessens the danger of detonation.

Check for engine overheating. A hot engine is more likely to suffer spark knock than one which runs at normal temperature. Overheating can be caused by a low coolant level, a slipping fan clutch, too small a fan, too hot a thermostat, a bad water pump, or even a missing fan shroud. Poor heat conduction in the head and water jackets can be caused by a or steam pockets (which can result from trapped air pockets).


Check for a lean fuel mixture. Rich fuel mixtures resist detonation while lean ones do not. Air leaks in vacuum lines, intake manifold gaskets, carburetor gaskets can all admit extra air into the engine and lean out the fuel mixture. Lean mixtures can also be caused by dirty fuel injectors, carburetor jets clogged with fuel deposits or dirt, a restricted fuel filter or a weak fuel pump.
If the fuel mixture becomes too lean, "lean misfire" may occur as the load on the engine increases. This can cause a hesitation, stumble and/or rough idle problem as well.
The air/fuel ratio can also be affected by changes in altitude. As you go up in elevation, the air becomes less dense.
A carburetor that's calibrated for high altitude driving will run too lean if driven at a lower elevation.

 

The 425 horse dual quad 409 motor cam from the factory with double stacked head gaskets ,,,,,,, you are quite right


geo

 

My first cam was an XS282S. It was a good cam but I wanted something a little bigger with my aluminum headed 454. I went with a custom ground ISKY solid 617\629 250 degrees at .050. Lobe center was ground at 108 and I installed it 4 degrees advanced. I have tons of low end torque and this cam actualy idles at 8-900 rpms where the XS282 I was lucky to be at 1050.

427HotRod helped me and tshort pick this cam that is based on a circle track design to move the torque down in the lower rpm range. I am very happy with it!!!

Wade

 

What compression were you running, what was the rpm range? I have a 5 speed that puts my rpm at 1800 at 65 in 5th do you feel that cam would work also how was your vacuum at idle. Thanks Gary