cougar9500

I just finished replaceing both head gaskets on my 440. Had the heads checked, had the valve guides replaced and valves done. I installed a new Comp Cams 260h cam. 21-213-4 part number. the cam came with new lifters and timing chain and sprockets.

I installed the cam as per the instructions, I lined up the timing marks at 6 and 12, then rotated the crank one turn before installing the distributor. at tdc, lined up the rotor to cylinder 1. i then advanced it just a touch before the initial fire up.

It started and ran poorly, i adjusted the distributor enough to make it run at 2200 to 2500 for the break in period, then it would not idle well.

I attempted to set the ignition timing at 8 btdc, but it wont run at idle there..

Strangely enough, it idles best and free revs best at 15-20 atdc.... but obviously has no power. if a bump up the idle screw enough for it to run at 8 btdc, it pingsd terribly as soon as i put a load on it....

Any ideas????

bremereric

ATDC is too retarded. Usually go for 10 to 15 BTDC and 34-35 total at 2500 RPM. Put a vacuum guage on it with it running and tell us what kind of vacuum your pulling at idle. Are you sure you lined up the two dots and not the 5 degree before or after square of triangle?

cougar9500

The new camshaft kit came with a new timing set. Cam sprocket has single dowel pin for alignment, no advance or retard positions on crank gear. only way to line it up is dot to dot. Vacuum at idle speed of 800 with 8 degrees btdc is 10 inches, way too low i know. Vacuum at idle speed of 800 at 15 atdc is 19 inches, right where it should be.... Ive checked the dampener with actual TDC, and the timing mark lines up at 0.


Engine ran well except for a hot misfire that turned out to be a head gasket leaking from cyl 6 into cyl 8 when hot. That was the only running problems before the head work and cam change.

Also no matter where the timing is set, it runs lean, I have a Holley Pro-Jection kit on it and i have to have the fuel trim set full rich for it to run....

Ive got this bad feeling that the dowel pin on this new comp cam is not in the right spot at all.... has to be retarded. Ive nevewr degreed a cam before, all the new stuff i work on at the dealership is diect bolt in and line up the marks... this one is really testing my patience......

bremereric

Remember a 44 magnum will penetrate an engine block.

440roadrunner

You should be running timing more like 15* BTDC.

ARE YOU CERTAIN

the cam is in time?

the timing marks are correct?

you are not "reading" the marks wrong?

Take a vacuum gauge, get the engine at the lowest it will idle, and slowly move the dist. for maximum vacuum, then see where the timing is

Frankly, I'd look up the cam specs for your cam, get a degree wheel, and see what it looks like. You can come "close enough" by indicating a lifter to see if the cam is out one whole tooth, of course on those engines, it's just about as easy to pull the intake.

ryan

Double check the spark wires and make sure their correct ccw 18436572. I agree that its allways a good idea to degree the cam in. It's pretty easy too. I've never not had aligning dot to dot not work out but its a good idea to double check, just like one would double check a crank with plastigage.

cougar9500

So i got a degree wheel and checked the cam.... with the cam advanced 2 teeth on the chain, the intake center line comes out at 108 degrees, cam spec is 106 degrees. I guess the dowel pin or timing marks on the timing set are off. Timing set is comp cams, and came with the cam kit..... frusterating.....

440roadrunner

2* is not all that much. It should run there, and depending on the build, it might just be OK. That is exactly why advance/ retard cam drives are made.

cougar9500

ok... now the plot thickens.... Got the cam to exactly 106 intake centerline... matches cam card exactly for open and close points for cylinder 1. reassembled and started up... again, will not run for crap if timing is set anywhere near spec of 8 degrees btdc. if i set it at 10 degrees atdc(retarded) it idles smooth and has good throttle response under no load... put it into gear and it just dies... if i crank the idle speed up to 1500 then it will idle in gear at 600rpm, but really rough... at that point it will accept throttle and accelerate, but anything more than 25 percent throttle and it falls on its face and starts pinging like mad.......

Ive tried 2 different distributors... both the same.... anybody think the cam is screwed up? it ran better than this when it had a blown head gasket.........

Mr.4spd

If you had the whole thing apart it could be unrelated to the cam, though. Maybe a vacuum leak?

cougar9500

so, it is all figured out.... Both of the distributors i had were garbage, one was an hei conversion off of ebay.... bad pickup... reman chrysler distributor was reman'd wrong, had small block internals so it was retarding timing with rpm instead of advancing. Warrantied that one out and now it runs properly... Who would have thought.... Now it has more power than ever and doesnt ping... Yay!