A local engine builder put a bug in my ear about advancing the E303 cam in my engine because I will be running a carb. What do you guys think??
Cam Advance for H.O
- Thread starter MUSTANG J
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itsaMustangtoo
New Member
advancing a cam increases low end performance as does retarding it improves top end performance. BUT , there is no way to tell you what to do without FIRST degreeing the cam to tell where it is at. Not all cams match the cam cards. I would probably just degree it and install straight up. With computer aided design and profiles( not to mention manufacturers) you should be able to find and install a cam you can be happy with. Good luck.
parthos
Founding Member
It use to be back in the dark ages, it was a common practice to advance the cam slightly. This was because of emissions, retarding the cam brought the emissions down slightly. So advancing the timing of the cam may have made sense on an engine that may only see 5000rpm. Usually performance timing chains take the correct the retarded timing, but the real way is to degree the cam, and get it right. If your local builder isn't going to degree the cam, I'd find another person to do the work.
My guess would be they recommend that to make up for the low end torque you lose by not having the tuned runners of the EFI.
If there's anything I'd complain about with my Mach 1's HO, it's the lack of low end torque. It screams above 3K rpm, but really is lacking below 3K. I've always just planned on "curing" the issue with 3.55 gears.
If there's anything I'd complain about with my Mach 1's HO, it's the lack of low end torque. It screams above 3K rpm, but really is lacking below 3K. I've always just planned on "curing" the issue with 3.55 gears.
Blue Thunder
Active Member
My suggestion. Install the cam at zero. Advancing or retarding the cam timing is a bandaid for an inappropriate camshaft. If you need less cam, buy a milder cam,(or build more motor)
Blue Thunder
Active Member
Interestingly enough, a magazine did numerous dyno tests and write up, comparing EFI to carbs. (I wish I could remember the name, it was at least 2 years ago) Anyway, the Demon carbs made more hp at the upper range than EFI, which isnt surprising. What shocked the testers was that the Race Demon carbs also made more low end torque than EFI.
Also, your low speed torque issue can be at least partially reduced by working on the fuel curve and/or ignition timing. Fuel and ignition timing can make or break the performance of any engine.
As an example, around 1994, working at a shop, I did a tuneup on this old, beat up, contractor's F150 with a 302 in it. Before I road tested it, the service manager told me that it was the fastest 302 truck he'd ever seen, and I laughed at him, because it was completely stock, and had about 100k miles on it. So I took it down the street, and that thing was so damn fast right off the line, it was ridiculous. It smoked the right tire for at least 50 feet. It wasnt just fast, either, it also sounded really good.
The reason it ran so good was because the factory happened to get that particular 302's fuel, ignition and cam timing exactly perfect, and man did it show.
Pay attention to details. Make it perfect.
Blue Thunder
Active Member
Every cam, even stock ones, should be degreed in exactly to spec. Even 1/2 degree off can make a difference. If a builder doesnt degree cams, he's not building engines, he's running a hobby shop.
