cam prob? Just throwing in my 2 cents.. My neighbor races circle trac and oddly has just had same prob. He tried to break in new cam with triple spring. BADDDD, VERY BAD. He was told to remove inner springs and vary RPM during break in.. Just as described above. worked for him..
Just as an update, this last cam went in over 2 1/2 years ago and has been running super since then. It will be roller all the way for me from now on.
i would definetly agree with you.....a good insurance policy as well so you know it was done right....the first time....
There is an article in the March 2006 CarCraft magazine about this. It's in the "What's your problem" section. They say the reason for this problem is becuase there is not enough zinc in todays oils for the Hydraulic flat-tappet cams & lifters.
I'm also looking to change my cam now since you have had problems with your cam. They just cost a little more. Do you still say it's worth it?
Yep - no zinc in oil. Use Shell Rotella oil (the diesel stuff) still has lots of zinc and/or a tube of GM EOS oil additive for your break in. Make sure the cam lube only goes on the face of the lifter. Do not allow cam lube to get on the bore side of the lifter....it will cause the lifter to not spin. Cleaver
We run a 351w in a sprint car on alky. Flat tappet cam, dual springs, at up to 8000 rpm. Oil restrictors to the lifters and top side. The breakin was single springs, 2500rpm +/- for 30 minutes. The engine must be as ready to do this as possible so the routine doesnot get broken.
Bluegrass I am in the process of building a 351w for a pure stock dirt car, can you explain the restrictors, i know how on a Ch...(is it allowed to use the C word in here?) Was wondering on any other mods for circle track use.
The oil restrictors are to reduce the amount of oil that goes to the top areas of the heads up thru the push rods and makes more available to the main bearings.. They are allen plugs with calibrated holes that are threaded into the oil gallery. Find them from Ford Motor Sports as part number M-6799-A302 for stock blocks or M-6799-R351 for race blocks, for a set of 5. Even with these in place, there is still lots of oil top side. Running without, at sustaned hi rpm, loads to much oil up top that can't get back to the pan fast enough. What are your general engine rules; maybe I have some comment to be of help in the power dept. There are fine tuning elements that brings power to these limited engines. Carb tuning has already been taken to a new level beyond even Barry Grant carbs etc.. Attended a carburation seninar last week and unknown to anyone else found out a secret being used by a fellow competitor during the talk. ( I never even asked the question) Then there is alot to know about gas quality yet before carb tuning begins. A fellow runs a 4500 holley on a 351w. The lowest airflow for this model usually begins at 1050 cfm, way to much for his engine, so found out how he was using it to success. That's all I will say here because I may do the same as we are moving from 1/3 to 1/2 mile Willims Grove Pa track for this year. No wonder he won't take the hood off! We don't much either. The Ford engines "under the present rules" are already making more power than the 350 Chevs on alky at well over 500 hp.
Thanks Bluegrass Checked my fordshelf and low and behold part no m-6799-a302 new in the bag. I assume the paper inside describes where they go. The class rules state stock intake (i am currently have an aluminum unit with ford part numbers), stock heads (ive got a set of 69 w bronze guides acid ported and a set of 70 stock), stock valves (was just gonna have local shop order stainless size ?) , springs are open(will get a set to match cam), roller rockers ok(will get to match cam), Holley 4412 carb w/ phenolic adaptor (ive got one we ran on a pavement LMS nascar motor), headers ok (got one set unknown and a Maverick set off a 302 coming, an i have a set of tri-Y collectors 2.5 outlet i was gonna try, was thinking of running 2 3" pipes and a Y to a 3.5" outlet, we ran this style exhaust on the LMS car and the dyno showed a torque increase) the rest of the engine supposed to be stock . I have heard about main bearing spacers thought about cutting the crank down and running less bearing surface/ reduce drag 351w bearings are pretty big . Im gonna need to find a good front sump pan at least i guess thats what the maverick uses? Ive got a set of stock pulleys that are about the same diameter crank and wp figuring on turning 6 maybe 65oo. Thinking aluminum radiator, any other cooling consideratons? I have 2 distributors a stock unit and a dual point (accell or mallory) cant run msd. Whats to much compression on a windsor? Plug recommendation? What about piston rings 1/16 1/16 3/16? Any other helpful hints would be greatly appreciated!
On your 2 barrel carb;there is something that you may need to know. Coming out of the turns WOT, the manifold vacuum goes low. As the rpm rises the small carb becomes a restriction and vacuum builds back up. What this can do is close the power valve and cause the engine to go lean halfway down the straight. Size the power valve accordingly. Do not change the main jets trying to correct for this if it happens. Compression, as high as you can get it per the fuel octane you run. Ignition, Dura Spark with electronic pickup and good coil,cap and rotors. Max timing 36 to 38* with centrifigal weights and springs tailored curve. Headers: step type 1-1/2 to 1-5/8" into your config. Cooling system. Run water pump at crank speed. Coolant tank with recirculation hoses and about 22 lb caps with good hoses. Cam; keep the lobe spread greater than 108* for wider power band keeping in mind the induction airflow has limits with stock type heads and the 2 barrel. There are small main spacers to be had but must be line bored and crank ground. Balance the rotating assembly with 157 tooth flywheel and clutch assembly or what you have to use. Good luck.
Thanks Bluegrass I ve got a dist machine what kinda curve should i try first. Thanks for the tip on the powervalve (the things ya forget over time) we ran into that in my camaro this paste year if we turned over 7k consistantly. We fixed by turning less rpms. On the step headers about how long of a run before increasing. Got a local guy who builds LMS headers about $700 for hand built units, not sure i wanna go that far, Dad just wants to have some fun.
