I am in the process of degreeing my TA 288-92H cam, which according to the TA literature is ground straight up, with no advance built in to the cam. When I check it with the rollmaster timing set keyed at +8 deg, all the events line up with the cam card almost perfectly. That means that the net installed timing on my rollmaster set would be 8 degrees retarded when set at the "zero" keyway. I have read a few posts that say it is usual for the rollmasters to be 4 degrees retarded, and I know of at least one guy who had to use the +6 keyway to get his TA cam to match the card numbers, but anyone else heard of 8 deg retard from a rollmaster set? Seems like a lot. To get the 4 0r 6 deg cam advance I want with this timing set I am going to have to advance the cam 1 tooth (15 crank degrees) and then use one of the retard keyways. When I advanced the cam 1 tooth and then re-degreed the cam using the -2 deg keyway on the crank gear, I get about 6 degrees advance, which is about right. Any comments?
Mine was +6. I had to jump the cam tooth by 1 and then retard to get thr cam where I wanted it. From the way I understand it the factory set was made having 4 degrees built in, roll masters are no . So there is instantly 4. If between when the cut the jetway or ground the cam there could be a few more. I wouldn't be surprised if you used a positive piston stop with the dampener installed you find the tdc on you dampener doesn't match tdc with the stop and wheel installed.
Same issue with a Cloyes billet 9 key set. Determined cam (Erson) was off, not gearset. TDC & balancer were right on. Ended up 1 tooth off on cam gear, 2 * retarded on crank gear to end up with 5*adv.
I also utilize the billet 9 keyway set and had this same problem when installing my TA-284-86F cam. I had to try all the things listed above as well. Installed it as close as possible to the cam card and it made good power.
Thanks guys for all the responses. Feedback much appreciated. Now that I know this situation is pretty normal, I can proceed with the rest of the build.
Many years ago my 308s needed +6 to dial in. Seems issues may be more “Cam Grind” related than gear-set. Larry
You can't blame it solely on the timing chain. If cams were ground where they were supposed to be we wouldn't have adjustable timing sets.
I should have bought a lottery ticket... 430 build. TA 413 roller cam. Cloys 9 key gearset. Dialed cam, 100% agreement per cam card. Cloys dropped in on 6 o'clock cam, 2 o'clock crank. Set 4 degrees adv as spec'd on cam card. Life be wunnerful. I have to pull the entire drivetrain, stuff in the rear end I got from JD Race, then stick the motor/transmission in and fire this ugly stepchild up. Figure, the next 8 weeks or so, and maybe bring it to Bowling Green in May.
I cant say where my custom SB cam is in at, bobb put in and I've never had the cover off........be interesting to see where its at. I dont know if there is different cores that could be used..........but if the core is ground assuming a stk chain which had 4 degrees advance built in as compared to one ground to be straight up. I know my gs 110 postons cam said it had 4 degrees advance built in.........not truly sure what they ment.......but that cam needed +4 to be ICL at 110
Wow when did they start coming already being remarked for the degrees......everyone I had was blank and i had to add them on
I used a tire white letter paint stick to fill in the numbers so I could see them. (I'm old and worn out...) The timing set was the Rollmaster Gold Series purchased within the last year.
Mine had to be 4 degrees adv to get the numbers to match. Here’s a question though, when someone asks did you put the cam in straight up? I answer no but the numbers matched up. They say “then you advanced the cam” Did I?? Really?
Yes. You are changing the valve events relative to crankshaft (piston) event at TDC. Mine is advanced 4 degrees, from 115 to 109 per the ideal on the cam card. When dialed in at "zero" the intake is at 115 degrees, and by advancing the cam it advances all the events by 4 degrees, while the crankshaft is still at that "zero" position. Valve event timing (is set incorrect to optimal) cannot be "rectified" by adjusting ignition timing. If I had only set the cam and crank "dot to dot", the valve timing events would be 4 degrees retarded relative to the crank (pistons) timing.
Ok now I am more confused, Since I set mine to match the cam card., wouldn't the valve timing be correct, or zero? If I set mine in at zero or dot to dot mine would be 4 degrees retarded right??
(Dagnabit. I hate when stuff confuses folks. Not the direction I want to see. I hope the rest does not add to the confusion.) I also edited my previous post, as I forgot to attach the cam card image. Can you post your cam card? It depends on the way it was ground. "Dialing in" serves twofold purpose. It verifies the cam grind is correct to the card. It allows you to make sure you have the cam optimally indexed to the crankshaft. And it goes hand in hand with phasing a distributor rotor to cap, so it is firing on the correct plug and at the proper time. It is possible that the "firing" event is either early or late relative to the cap and rotor, and if too far off, can result in "cross fire",a bad term, to describe the ignition firing too soon or too late and discharging to the post before or after the plug it should be firing on. For example, the rotor and post of plug #1 ideally should fire with the rotor blade as close to the cap's #1 post contact center as possible. If it is too early, it may incorrectly fire to #2 post, or too early to the #1 post. And if it is late, it may fire incorrectly to the #8 post, or late to the #1. post. And any of those will result in "misfire" symptoms, and or detonation. The above is more about getting near perfect in timing issues, and further than a lot of people will pursue. And it is not a real problem for most, but some folks figure not doing these things is "leaving free horsepower on the table. Doing them in during the build and break in and tuning will provide the benefits for the life of the engine, so 1 or 2 MPG and a few % HP is worth it for those that want to take time to do them. "back in the day" a lot of people drove cars with very poor "tunings". Yes, they ran, but they " dieseled " when shut off (run-on), were hard to start, hard to keep running, "rolled coal" (black exhaust) like a diesel when at heavy throttle, pinging and rattling, and all manner of things. Most classic cars today are better tuned because folk spend time with their cars, when people used to just drive like most folks do with daily cars, but the advent of technology allows computers to "manage" enough that it takes a problem with something to trigger "check engine light". In the past, people drove them in poor tune until they would not run, or it was too bad to deal with. But many of us remember cars smoking, rattling and wheezing, as a handful of badly maintained cars were sprinkled in the daily drive. Once those are set, other adjustments are "fine tuning".
If your events that your measured match your card it's in at 0.......even if you had to be advance orvretard to get there. To advanced the cam it would read different from the cam card........example if card calls for 112cl and your were in at 108cl then it would be advanced
