440 headgasket to lower compression

[TN Mopar]

I believe the OP has an issue with oil burning or carbon build up

But I am going to stir the pot a little
IIRC He said the eddy chambers were the 75cc ones
This is the one I run
since he has this apart, I think He needs to consider squish
With his pistons, (0.020 in the hole) He can get .047 squish by using a Cometic 0.027 head gasket
this combined with the aluminum heads will make for a much more efficient cylinder
allowing him to run the higher compression ratio this will provide

there are 2 limits to be considered
1) the limit of 91 octane gas
2) the camshaft duration (his is unstated at this time)

my combination is the same
0.020 in the hole, 75cc Eddys, 0.047 Squish
I have 10.7:1 compression & 36 degree timing at 3000 RPM with no Vacuum advance
running the old Purple Shaft 509/292 cam

I have no detonation issues at all
The car runs better than I thought it would
However, I can get 93 Octane here in Tennessee on a regular basis

 

[68-500]

What do you mean by retard it back to 112 degrees?

Your lsa is 112*. Your icl is 108* if the cam is ground accurate and the timing set is correct. Alot of aftermarket timing set have 3 or more settings for cam timing. 0, 2* advance, 2* retard. Some maybe 4* increments. If you retard 2* your lsa will still be 112 your icl will be 110. If you retard 4 it will be 112/112. Your cam will be installed straight up. As it is now cam is 4* advanced.

Please do your homework before you make your changes. You can run ito valve to piston clearance issues.
I believe the op could also have similar issue to much advance on cam.

 

[kaj750]

Your lsa is 112*. Your icl is 108* if the cam is ground accurate and the timing set is correct. Alot of aftermarket timing set have 3 or more settings for cam timing. 0, 2* advance, 2* retard. Some maybe 4* increments. If you retard 2* your lsa will still be 112 your icl will be 110. If you retard 4 it will be 112/112. Your cam will be installed straight up. As it is now cam is 4* advanced.

Please do your homework before you make your changes. You can run ito valve to piston clearance issues.
I believe the op could also have similar issue to much advance on cam.

I, for one, have no idea what any of those abbreviations mean.

 

[kaj750]

I believe the OP has an issue with oil burning or carbon build up

But I am going to stir the pot a little
IIRC He said the eddy chambers were the 75cc ones
This is the one I run
since he has this apart, I think He needs to consider squish
With his pistons, (0.020 in the hole) He can get .047 squish by using a Cometic 0.027 head gasket
this combined with the aluminum heads will make for a much more efficient cylinder
allowing him to run the higher compression ratio this will provide

there are 2 limits to be considered
1) the limit of 91 octane gas
2) the camshaft duration (his is unstated at this time)

my combination is the same
0.020 in the hole, 75cc Eddys, 0.047 Squish
I have 10.7:1 compression & 36 degree timing at 3000 RPM with no Vacuum advance
running the old Purple Shaft 509/292 cam

I have no detonation issues at all
The car runs better than I thought it would
However, I can get 93 Octane here in Tennessee on a regular basis

I actually don't have any of that.

 

[33 IMP]

LSA is lobe separation angle. Ground into the cam by manufacturer. Can't be changed except by regrinding the cam.
ICL is intake center line. This is where the camshaft timing events occur in relation to crank/piston position. This is determined by timing chain/camshaft/crankshaft interface, and can be adjusted (or MISadjusted) with keyways, offset bushings, or timing sets with multiple positions.

 

[Curiousyellow71]

Degree of Difficulty…How to Degree a Cam with a Few Simple Tools

 

[Zeppelin264]

I will add that CA gas is only 91 octane + 10% ethanol which is terrible for these older motors. I also run the Sniper 2 system and on my new motor, I'm also dealing with detonation right now. Already have Trick Flow 240's and can adjust timing on the fly but its been a struggle so far trying to work through the tuning stage.

So far I can control the pinging with a 1 heat range lower plug and maxxing the timing to 30 degrees which for this 505" motor is really killing the power.

 

[68 Sport Satellite]

I will add that CA gas is only 91 octane + 10% ethanol which is terrible for these older motors. I also run the Sniper 2 system and on my new motor, I'm also dealing with detonation right now. Already have Trick Flow 240's and can adjust timing on the fly but its been a struggle so far trying to work through the tuning stage.

So far I can control the pinging with a 1 heat range lower plug and maxxing the timing to 30 degrees which for this 505" motor is really killing the power.

do you think the wrong pistons were chosen for this motor? That was my mistake with mine.