Hi All,

Has anyone ever had any trauma dialling in a Howards solid roller cam? I just cant get mine even close. it seems like its ground 10 degrees retarded. all the numbers on the card are spot on, bar rhe intake centreline which is 118 instead of 108. Its a 111113-12S.

Any thoughts guys?

 

Not being "there" and not being able to see what you see, and not knowing your abilities, impossible to say.

Maybe you can detail the procedure you used?

How did you establish TDC?

How are you determining centerline?

 

Essentially, TDC determined using a piston stop and clockwise and counter-clockwise rotation.

Intake centreline identified by rotating the assembly past max lift till .100"drop and recording the degrees, then counter-clockwise back past max lift to about .150" drop, then forwards again to .100" before max lift and recording the degrees. Ad the two together and divide by two. which gives me 118, not 108.

 

I'm going to take my wild ass guess and venture that the timing chain is off a tooth.

 

If all of the opening/closing events are spot on then all I can imagine is the intake lobe is ground asymmetricly. Try taking your readings at .010" instead of .100" and see what you get. Might want to give Howard's a call and see what they say.

 

^^^ this, but not off a tooth. We used to find many timing sets that were off because of tolerances, line boring... ect. I haven't come across 10* off before, but with all the imported parts, you never know. Could even be a crank issue if its an aftermarket. If you can repeat the procedure, and get the same results, I would look at the timing set first.

 

Twp cranks and two timing sets, same results.

Maxxed out the adjustable chain and got 6* advance last night and i get 107.5* ILC. and intake opens 5* late.

The crank gear has no advance keyway in it, I wonder if i use a crank gear with advance built in, together with the adjustable cam gear, i might get some adjustment back.

 

If you have ruled out the timing set, and the key location on the crank, you could check center line at a location closer to max lift like posted earlier, if that checks out, and your numbers are repeatable, it almost has to be how the cam is ground. What brand of timing set? Adjustable cam gear?

 

the ICL aside, the Intake opening is still 5* late at 10* not 15*. so i think i am still a few degrees off.

Its a Comp cams vernier style chain kit.

 

Are you on the intake valve and not the exhaust? Why not go .050 before max and .050 after max and read what you have? Also even though the chain is new is it tight or a little loose? I've had better luck out of PBM Billet chains always degreed right in and tight, have had problems with Cloyes hex adjust "Loose chain" and I think they make Comps Timing sets for them.

 

Surely i couldnt be that stupid.........

Or could i....

 

Aren't there two different sbc key locations

 

TDC is tdc don't know of 2 diff. key locations on crank. There are two different balancers with diff. tdc marks in ref. to the key in the crank but this shouldn't cause a problem when degreeing in since you don't use the marks on the balancer you use the wheel. He could have a mixed set timing set but still should be able to degree. The pin in the cam could have been drilled a little off also but should be able to degree.

 

A piston stop accounts for any variances in balancers pointers etc. If he got tdc in the right place it is correct. Called Howards?

 

Pulled everything back out, and put it all back together again. this time at 0*, timing events come up 1* advanced. Happy times.

Now going to go with 2* retarded to lessen the low end cylinder pressure, hopefully keep it out of low end detonation. It should still behave OK off boost.