11 to 1 with stock cam/sparks key??

[VTredneckgames]

I have heard so much differences in opinions on this matter.

Id like to end it and get the facts.

2004 400ex, 86mm bore, stock exhaust (ground welds), openish air lid (outerwear lid mod)

First off, With a stock cam, will a 11 to 1 piston be okay? I know the stock cam will have a higher dynamic compression. Im running the cometic base and mls head gasket so that should drop the static compression to 10.2:1 right? So I think I should be fine.

Second, I have a timing key, but not installed. If I do the above, would you recommend installing it? I know it will create more heat, I have a spal fan, and will be getting air scoops next spring. I know the website says dont do with high compression, but from this site, most people say they mean high as in 12:1 and higher.

Thanks, just want to get this settled.

[supertrooper90]

When I spoke to the people at powroll about doing my 10.8:1 piston, they said not to use the key. It could cause detonation. I will be taking mine out.

[sab24711]

key + hi compression= boom

[VTredneckgames]

so with even more searching and reading old posts,

I think I will be fine with 11:1 and stock cam.

And with that compression and running a timing key can be done, but you almost certainly have to run race gas to avoid detenation.

Anyone else??

[VTredneckgames]

well I finally found a thread that has this covered. So many topics on here that it actually gets hard to search for exactly what you want to know.

Anyways, it was asked, not too long ago, (I regret for the added post)

Wheelie, who did make some +4 keys advised to not run 11:1 with a sparks +6 key. With 100 octane, he experienced mid range spark knock. When he dropped to +4 and went to 102, it fixed the mid-range problem.

Therefore, if you do not want to run atleast 100 octane ($7/gal around here compared to $2.50 for 93) then dont run it. Some people may get away with it, but for the most part it causes problems. With my luck, it will cause problems.

I am going to sell the key for now and run without it.

Thanks for the help guys.

[Wheelie]

As VT stated, the +6 key with 11:1 creates too much heat.

FWIW--I'm ordering more keys Monday and I'll be machining them for a +3 advance once I receive them.

[Ntensweapon]

I still want one Wheelie. Let me know when they are ready. I'll even pay in advance. Glad to see you didnt drop the idea.

[VTredneckgames]

put me down for one when you get them Wheelie.

Thanks