Camshaft timing

[Katz427]

Well guys, I have a car in the shop, comp cams installed by owner. The cam card says 110 + 6 degrees. The car came in running, but off on power, the cam was installed straight up. Compression  is good, so I'm going to check the cam timing. Does this 110 +6 degrees mean advance the cam 6 degrees, or is it that the camshaft itself was machined already 6 degrees in advance ?? I only have a few specs on the camshaft, like total lift, and lift @ .050.

[My427stang]

With no stacked tolerances, a 110+6 cam should degree at 104 ICL, the +6 is already in the cam grind.  However, +/- regularly occurs due to all the differences in machining.

However, just to clarify, straight up means ICL and ECL are equal, so in this case "straight up" would be 110 ICL.  My guess is you mean it was installed at zero advance of dot to dot, that is unless you degreed it and it is indeed at 110 ICL.

Cam timing would have to be WAY off to drive a complaint, unless the cam was already mismatched to begin with.  What are the engine and cam specs?  Have you looked at the ignition timing curve?

[Katz427]

Thanks Ross, yes the owner installed it dot to dot. He claims little low end torque. I did check timing, about 15 degrees advance at a 850 rpm idle. Hit a max of 35 degrees. This is a stroked 351 windsor, not sure if it is 4 or 4-1/8" stroke. Afr heads ,12 to 1 compression, rpm air gap, toploader, with 3.50 gears. I feel it may need more gear, but that's  another deal. Owner took me for a short ride, it is not happy at low speed cruising, has a vibration it goes thru at around 2100 rpm, then settled down. Owner feels it is down on power, I couldn't really tell from my short ride. I have the front off now and the timing marks are dot to dot.

[cjshaker]

12:1 compression is stout. It sounds like the rest of the engine is built around that parameter. If the cam matches the rest of the engine build, it most definitely won't be very happy under 2500-3000 rpm, minimum. Those gears, especially with a manual gearbox, will cripple the engine at lower speeds, in any gear. "He claims little low end torque"...sounds about right to me. I'm guessing the engine starts to come alive above 3000-3500 rpms?

[My427stang]

Thanks Ross, yes the owner installed it dot to dot. He claims little low end torque. I did check timing, about 15 degrees advance at a 850 rpm idle. Hit a max of 35 degrees. This is a stroked 351 windsor, not sure if it is 4 or 4-1/8" stroke. Afr heads ,12 to 1 compression, rpm air gap, toploader, with 3.50 gears. I feel it may need more gear, but that's  another deal. Owner took me for a short ride, it is not happy at low speed cruising, has a vibration it goes thru at around 2100 rpm, then settled down. Owner feels it is down on power, I couldn't really tell from my short ride. I have the front off now and the timing marks are dot to dot.

A 12:1 stroker with AFR heads should jump and jump hard, maybe verify firing order, although it would shake more than a 2100 rpm wiggle.  Got a carb you could throw on it?  We had an AED years ago that only made 350 HP on the dyno, couldn't figure it out, and couldn't tune it out, swapped carbs went over 500 HP instantly.  Turns out it had some mismachined passages (and it was an original CJ carb to boot) 

As you said, I would look at is gearing too, even a stout Windsor stroker would be soft low if it's a close ratio and a 3.50 gear (8.12 compound ratio)

[blykins]

Thanks Ross, yes the owner installed it dot to dot. He claims little low end torque. I did check timing, about 15 degrees advance at a 850 rpm idle. Hit a max of 35 degrees. This is a stroked 351 windsor, not sure if it is 4 or 4-1/8" stroke. Afr heads ,12 to 1 compression, rpm air gap, toploader, with 3.50 gears. I feel it may need more gear, but that's  another deal. Owner took me for a short ride, it is not happy at low speed cruising, has a vibration it goes thru at around 2100 rpm, then settled down. Owner feels it is down on power, I couldn't really tell from my short ride. I have the front off now and the timing marks are dot to dot.

It will be either a 4" stroke (408), 4.100" stroke (418), or a 4.250" stroke (434), if it's a stock block. 

Most guys over-cam, so I'd say Doug has probably hit it on the head.   It will most likely come alive after some foot-time. 

FWIW, I haven't seen a ton of difference while swinging the cam timing to extremes.  It's not like it will lose/gain 50 hp. 

[Katz427]

Yes, it is a close ratio toploader. IMO ,I would think it needs at least 4:11 gears. When he ordered the cam, he told me he was going to race the car, so I believe he planned  on something  in the 4.11, or better range. I will check out the carburetor,  it's a holley , I have not checked the number,but he believes it to be a 750.  Yes, Brent it is 4.1, stock block,Again, thanks for the comments, I can't  plug in the code reader on this one!

[Joe-JDC]

Unless the RPM-AG was ported to match those AFR heads, it is not going to be the best manifold for that engine.  I raced a 351 for several years, and I have ported several versions of intakes for a 351.  The RPM-AG is a street intake if it is box stock, not a stroker intake.  The heads flow more than a couple of the intake manifold runners flow.  He needs a Victor Jr at the minimum, and a Super Victor would be even better.  I have NEVER experienced low end torque issues with any of my 351W builds.  I have built and raced 357/376/383s personally, and built several stroker 400/408/427/434 versions for others.  The camshaft may not be the issue, but the close ratio 4 speed needs at least a 3.90 or lower ratio.  I ran 4.57 gears in my Mach I with 10.5 x 28 slicks.  Joe-JDC

[Katz427]

Just in case anybody interested the cam did check out, as designed. After talking with the owner, he decide on another camshaft with less duration and a bit less overlap, though the lift, is still .590, so hopefully use the same pushrods. Also he agreed that he needs 4.11 gears or something close.  I also found the carburetor needed some help, warped throttle plate. Everyone - Thanks for your replies.