HELP!!!!

So I am about set to order the new cam/trans./gears/flycutting stuff and then I come across this thread O NO.... https://ls1tech.com/forums/generation-iii-internal-engine/806151-milling-205-afr-s.html

So I am reading along I see post #16 talking 59cc AFR 205's (which I have) and someone using a cometic .040 gasket (which I was going to run). He says that the compression on that would be 11.83-SCR which as I now understand is in the zone of requiring a much higher octane gas? Also, he wrote that 59cc is .042 milling and I have heard from most other places that it is .030. Someone with knowledge could you fill me in... I'm really hoping I catch a break on this one.......

-Rob

 

I dont think the CR is usually that high. I think its more in the 11.3-4 range.

I could be wrong, but I think im right

 

I was thinking the same thing, I have done lots of research about these heads and I have never seen a number that high before...

 

Maybe .042 milling if you are refrence to 241's and .030 to 243's?
241= 67cc; 243= 64cc

To my specs Im running 11.9:1 on 93, so far no knock retard but I forget how much timing I have.

 

In Cali. it's really hard to find 93 and if we do you have to give the gas station an arm and a leg for it...Basically, I will only be running 91, unless I find myself somewhere close to a race track

 

On AFR heads, a flat cut @ .006" = 1cc. I have .036" cut from mine for a 59cc combustion chamber. I would have no problem running .045" Cometics with a nice quench and 11.5 to 1 compression ratio.

 

jub jub, running pump gas?

 

I was running 62cc with .045 gaskets and ~11.3, more importantly where is your dynamic compression?

 

With a .040 gasket and 59cc heads I think that would be too much compression for 91 octane.

 

I have no clue where mine is, I am yet to do a compression check...in that thread he said it would be 8.87 DCR

 

Im gona be right at 8.86 and im in texas with decent gas. Im using every anti detonation trick in the book. I would try to get yours to around 8.5-8.6 to be on the safe side.

 

DCR is what you need to look at, not just SCR. Obviously the cam is a big part of the equation. 8.87 is slightly more than I shoot for with 93 octane, but if your not getting any KR then all is good. I think 8.6 - 8.7 is ideal. The higher you can get away with the more torque you will have, all things being equal.

 

So the thing is all this talk is with the cometic gasket right? I think I am going to use the GM MLS gasket, rather than the cometic, I would much rather lose a few ponies and have a motor that wont blow

 

mine blew...#7 piston...booom!

 

You can get cometics in different thicknesses. If you want to lower your DCR a little, recalculate it with .045 and .050 gaskets to see what you need to put it where you want to be.

 

jee wizz so what does that leave me to do? I ran this setup for about 7,000 miles before the trans shot with out any engine problems....

 

Wrong!! Mamo spec' ed my stuff 59cc 11.3:1 .040 cometic, no issue what so ever on 91 octane. My car runs great we have the worst gas in the country in Oregon.

 

Theres nothing wrong with your setup. Call Tony Mamo next week when SEMA is over and ask him. He knows AFR's better than anyone else, dont be panic'ed. I run the same head at 59cc. Different cam but if thats all you need to do then your fine

 

not to be gay but I love you BlancoSS, you just made my week... I'll hit Tony next week just to make sure

 

Hmmm interesting