advanced cam timing????

[Nucking futs]

I just advanced the cam timing 4*.Will this affect my initial and full advance on my ignition timing?Or just leave it where it was?It ran best @35*and i know this will change now but i was just wondering where to start the tuning process.Do i start @the 35 or back it down to say 32 to tune my way up after the plug readings and such?Any input would be great thnx tim

[Fiat48]

Why did you advance your cam 4 degrees?

[Nucking futs]

The cam im using is rated for a little higher compression than i have and the cam tech at crane said to advance it to get the cyl. presure a little higher to compensate for the lack of compression.Also the cam peak is 6500 and i am only turning 5200 or so.The cam is a crane roller598/610/292-298@.050/112 lobe seperation and high compression is recomenned 10.0-11.50/1 and ive only got about 9.2-1comp. with the head work done.

[Fiat48]

292/298@.050 is a whole lot of camshaft. I'd have to say way too much camshaft for that compression. Anyway, I wouldn't back down the timing. Leave at 35.
If you've given the right cam specs, sounds like the wrong cam for the application to me.

[Nucking futs]

What would be a better choice?maybe 1 step down?I ran this cam for a couple of seasons and it ran good with alot of pull but i have had done more head work and thats why i advanced it.The crane tech said the cam is one step up from what the merc 502 uses and he said it would run alot better advanced.I agree with you and thats why i cakked to get info on another cam but he said try and advance it befor i spend another 350 on a cam. Thanks for your input,the engine is a 468 and has just been freshened up so would you try this or just opt for the new cam?

[Dave C]

Merc doesn't use a cam that is 298/292 @ 50. Thats too big. too much duration. @ 9:1 that cam would not work.
IMO, 260 @ 50 is enough for 9:1.
but thats me!
:D

[Nucking futs]

The crane tech said the cam is one step up from what the merc 502 uses and he said it would run alot better advanced
that is my question,and the cam i have now is one step up from the merc .What would be a good cam choice for a jet boat and the engine set up?ported oval port heads 2.19/1.84no flow data,468chevy,duel plane weiand 850 d/p and headers

[Nucking futs]

It was brought to my att. that is the adertised duration hows this sound 598/610-230/236@.050

[LakesOnly]

Originally posted by Nucking futs
It was brought to my att. that is the adertised duration hows this sound 598/610-230/236@.050
Futts, this is much more like it...though a surprising amount of lift for the duration...
You would have had dismal dynamic compression if that advertised duration was in the 290's!
Fiat's advice on the ignition timing rings true.
LO

[LakesOnly]

(Double Post)