Fms camshaft questions

[FestYboy]

sweet, but use stainless or mild steel for the header (as thick as you can get) and use it as far back as the shifteror at least untill it passes under the steering rack.

ok, wait, you're in PA... i know theres a visual tamper test to any car after '74 at the MINIMUM for any area of the state and in the northern region, it's part of the safety program/test.

[FB71]

flat (non-roller) are the stock Festy followers.

Artie; it's not just the apex, its the leading and trailing ramps as well. They tend to be more abrupt on a roller cam, which neccessitates a smaller base circle to maintain the lift. The base circle is only one clue to the puzzle, but one of the first ones I look at.

[FB71]

Also the exhaust that I will be building will be mostly aluminum,

be prepared to repair and replace it often. Aluminum does not like the caustic gases present in combustion engine exhaust. It corrodes very quickly.

[rollertoaster]

I inspect my own cars so.... I'm pretty sure it's gonna pass, LOL. I'm gonna use mild steel for the header and coat and wrap it. Then a resonator after the flex, aluminum after that until it gets to the muffler. The resonator will go back to about the shifter and I will be replacing all the steel heatshields with aluminum and making a new one to protect shifter bushings


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[FestYboy]

i always thought the smaller base circle allowered for faster ramp up and down speed to get the valve to full lift as fast as possible for highest flow potential. then to allow for such agressive ramp speeds, the follower tips (or lifters) required a roller to reduce friction and keep the folloer from gouging the lobe durring the lift event (highest point of friction and pressure).

[Bert]

I built a 'sprint' engine years ago for slaloms and it featured a 'streetable' race cam, double valve springs and larger valves, among other things. To ensure it had a proper break-in period I put it together with a dinky carb and no header. The poor devil had no power (couldn't move enough air or revs) but the gas mileage was spectacular during that 'drive like a little old lady' 500 mile run!
Significant increase in power for a given engine comes largely from increase in revs. Standard B3s don't do much beyond 5000rpm and once you cam, valve and fuel the engine beyond that number (say 7500rpm) it starts costing serious money if you want the motor to stay together for long periods. This might get you 80 hp. On the other hand displacement is the cheapest and easiest way to achieve that same power. Americans have been doing that to all manner of otherwise-sedate cars (AC Cobra, Sunbeam Tiger, MGB-GT etc) for years. A stock 8 valve BP (1800cc) just by virtue of displacement can/will produce 1/3 more power than a B3 (1300cc), and, it will still be reliable and use ordinary parts.
In my way of thinking (especially remembering back to all the learning curve woes of trying to use stock parts (aside from the cam and fuel/exhaust system) on performance engines; planning for a 'big block' is a much better way to go.
And then if you really want; soup that one up. You'll still have a B3 in reserve for when that motor burns or blows up.

[rollertoaster]

be prepared to repair and replace it often. Aluminum does not like the caustic gases present in combustion engine exhaust. It corrodes very quickly.

Yeah I know about the corrosion but I'm willing to trade longevity for weight savings. I can get the aluminum tubing for $1.50 a pound. Besides mild steel would only last 2-3 years around here anyway. I would make it from stainless but it's not cheap, it's heavy, and it ruins cutting blades very quickly.


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[ELUSIVE]

I humbly stand corrected.

[FB71]

i always thought the smaller base circle allowered for faster ramp up and down speed to get the valve to full lift as fast as possible for highest flow potential. then to allow for such agressive ramp speeds, the follower tips (or lifters) required a roller to reduce friction and keep the folloer from gouging the lobe durring the lift event (highest point of friction and pressure).

yup, exactly. So the ramps are more abrupt (almost like hitting a wall, instead of a gentle climb).

[FB71]

Yeah I know about the corrosion but I'm willing to trade longevity for weight savings. I can get the aluminum tubing for $1.50 a pound. Besides mild steel would only last 2-3 years around here anyway. I would make it from stainless but it's not cheap, it's heavy, and it ruins cutting blades very quickly.


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OK, just making sure you were aware. Didn't know they salted that heavy up there.

[FestYboy]

^ in what respect, Elusive?

[FestYboy]

yup, exactly. So the ramps are more abrupt (almost like hitting a wall, instead of a gentle climb).

so why not use rollers on a larger base circle?, it should be much easier on all parts involved (except the cam in our case).

[rollertoaster]

Yeah, I don't want a bigger engine in this car. If I change the engine, ill need a tranny swap too and i dont want to throw that amount of money into the car right now. I'll be happy with 80hp in a 1400lb or less car. I have a lot of fat trimming to do but that's another subject for another thread.


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[FestYboy]

^ again, i suggest the B6 head.... but you reconed a B3 so...

did you remove the exhaust shelf from the runner?

[rollertoaster]

OK, just making sure you were aware. Didn't know they salted that heavy up there.

Lately the winters have been pretty bad so there has been a good deal of salt. I drive this car everyday to work so it doesn't get to avoid salt.


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