[Stripes]

Camming our 455 (60 over) Pontiac; I purchased hyd roller cam BP8031SP from Butler, ground by Comp Cams. Butler Item #: CCA-BP8031SP.

Cam card arrives, card calls for a 110 intake centerline, and a 114 lobe separation. (cam is 236/242 dur at .050) (see attached)

I install the cam straight up with a new Rollmaster timing set. Checking the intake centerline and came up (three times) with 111.75 intake centerline. I thought I was going to find the advertised 110 intake centerline!

I call Comp who provides me with the specs for MY serial numbered cam. Appears they check every cam before it leaves. They say my cam measured 114.01 lobe separation and 2.630 degrees of advance. Comp says it should have 4 degrees of advance, but it wasn't rejected since it was +/- 2 degrees of spec.

Should I advance the cam 2 degrees, then it will be 4.630 advanced. Or should I leave it at 2.630 degrees advance? 2 degrees is the smallest amount I can move keyways.

Does the advance difference cause the finding the centerline of 111.75 verses the listed 110 degrees? Seems to me a greater centerline number would indicate less advance since 114-111.75 = 2.25 degrees of advance. Do I understand that correctly?

[Lee]

If you are running 3000 or more stall speed, then I'd leave it where it is.

I'm assuming you have aftermarket heads, or at least some quality porting.

[Stripes]

469 at about 10.2 to 1, 87cc Edelbrock D ports, 2200 stall, 3:55 rear gear, 700R4, (equates to a 4:20 gear in 1st) long branch w 2.5" mandrel-bent exhaust, stock intake, either a Rochester or Holley 800 carb.

[Stan Weiss]

Comp Cams checked the cam but you are checking the cam and timing set and crankshaft key way location altogether. If you are at 111.75 and advance the cam 2 degrees you will be at 109.75 that is just .25 degrees off what is called for.

Stan

[Lee]

I suggest leaving it as-is, and see how it works. Then, if the low-end is just a bit softer than you like (but I doubt it will be) then consider advancing it.

[Stripes]

Thank you all for the responses.

If you advance a cam in an engine, do you use to +2,+4,+6 Keyways on the timing set? Does that rotate the cam clockwise in the Pontiac block?

Another source said for me to retard the cam 2 degrees to get closest to the 110 centerline.....so now i'm confused.

[68lemans462]

I used the MOPAR offset woodruff keys to degree my cam. Worked great.

[Mike Davis]

Originally Posted by 68lemans462

I used the MOPAR offset woodruff keys to degree my cam. Worked great.

Since they have discontinued the set of keys (I think there were 6 in a set) do you have a source?

I need a 1 deg which will be 2 and the crank.

[gtofreek]

I would definitely advance it 2 more degrees to get it at least down to 110 ICL. That will make it idle better, have more power where you need it, and make it less likely to detonate. Retarding it is a very bad idea to who ever suggested you do that. I have seen Rollmaster sets give the full 2 degrees on there key slots and have also seen them change the timing as little as 1/2 degree so you need to put it on the 2 degree advance slot and see where it winds up at.

[mgarblik]

Originally Posted by gtofreek

I would definitely advance it 2 more degrees to get it at least down to 110 ICL. That will make it idle better, have more power where you need it, and make it less likely to detonate. Retarding it is a very bad idea to who ever suggested you do that. I have seen Rollmaster sets give the full 2 degrees on there key slots and have also seen them change the timing as little as 1/2 degree so you need to put it on the 2 degree advance slot and see where it winds up at.

I agree with this. Rollmaster sets are all over the map with their keyways. That's why it's imperative to make the change and verify what actually happens. For accurate multi-keyways to adjust cam timing, Cloyes is the only way to go IMO. If your Rollmaster 2 degree keyway doesn't get you where you want to be, then I would go to the offset keys to fine tune. Mr. Gasket still sells 1 and 2 degree keys. Also Mercedes Benz sells 1,2,3,4,5,6 degree keys that will work for some of their weird engines. I have the part numbers here somewhere if you get in a real jam.

[Mike Davis]

Originally Posted by mgarblik

I agree with this. Rollmaster sets are all over the map with their keyways. That's why it's imperative to make the change and verify what actually happens. For accurate multi-keyways to adjust cam timing, Cloyes is the only way to go IMO. If your Rollmaster 2 degree keyway doesn't get you where you want to be, then I would go to the offset keys to fine tune. Mr. Gasket still sells 1 and 2 degree keys. Also Mercedes Benz sells 1,2,3,4,5,6 degree keys that will work for some of their weird engines. I have the part numbers here somewhere if you get in a real jam.

Mike, do you know where to get the 1deg key? Would that be the Silver one?

[77 TRASHCAN]

Originally Posted by Mike Davis

Mike, do you know where to get the 1deg key? Would that be the Silver one?

Mr. Gasket, used to offer a 1 and a 2 degree...may be packaged as a Mopar part...

[Cliff R]

Far as I know the excellent Mopar set is long discontinued.

The Mr Gasket 2 degree key should still be readily available.

A google search may turn up a Mopar set. I bought two couple of years back on Ebay but had to pay dearly for them. I'm probably one of the very few on here that will NOT use a roller timing set on my engine and prefer the old stock factory 3/4" wide Morse chain set-ups.......Cliff

[shoebox1.1]

Cliff what timing set in particular to you run?

[Stripes]

Ok, we switched to the +2 keyway and tooth. A recheck of the intake centerline results in 109.75. The goal was 110, so I believe that's close enough.

I'm still in disbelief that Comp Cams uses a generic cam card with incorrect info when they have the correct info on hand. Had I known the cam was ground with 2.63 of advance instead of thier advertised and documented cam card figure of 4 degrees of advance, I could have understood this much sooner. I dont see how a cam company can have a +/- 2 degree slop factor like COMP CAMS themselves state. For the hundreds on the net who claim they always check ther cams numbers and they are always 100%, I dont believe you anymore!

[grivera]

Here is the Mr. Gasket 2 degree key:https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[Cliff R]

"Cliff what timing set in particular to you run?"

I will only run factory type sets and prefer "old stock" ones so I search them down on Ebay and keep 2-3 on the shelf.

The best will have the "black" heat treated steel sprockets and good USA made Morse chain. These will last the life of the engine and then some.

The newer variety from Melling are decent, (they are also marketed by Cloyes and Dyna gear but appear to be the same origin) but use iron sprockets and not heat treated. Still stronger than any roller variety, and constant tooth contact to smooth things up for the distributor. IF you don't think a Morse chain is stronger take a look inside every transfer case that uses a chain instead of gear drive and see if you find a double roller in there? They wouldn't last to the bottom of my driveway in 4 x 4 mode...FWIW

Nothing at all wrong with the "high" end roller sets, the ones with the imported true roller chains and billet sprockets. They fair fine in these engines, but few if any folks will ever log enough miles on them to find the true life span. I'm not on here to argue timing sets or steer anyone in any particular direction. It's what I do here and they have been 100 percent dead solid reliable dating back over 40 years. The few times I deviated got bit in the backside so hard lessons learned guide my decision making process when it comes to these parts.

I tried a Rollmaster for a Pontiac once, it did fine for a couple of years then the chain failed (stretched out) and the engine lost power, a LOT of it. I was street driving the car at that time and drag racing it couple of times a week. I liked the easy camshaft degreeing with the 9 keyway deal, but my timing always "bounced" too much for my liking when you followed it at high RPM's with a timing light.

Went back to the good old link best set-up and the timing mark became rock solid and no more worries about stretching out a "bicycle" chain and having to replace it.....FWIW.....Cliff

[firechicken]

Cliff is right. I found all bicycle chains to be garbage including top dollar billet marketing heroes. Link belts were hard to come by at the time so I ended up with a Milodon gear drive and got happiness. .

[gtofreek]

Then why is it that every engine I tear down with a link belt setup, the chain is super loose. My V-6 in my S-10 had just about 100,000 miles on that link belt set and it was so loose that it kept jumping teeth when I shut the engine off. When I changed it, I could literally lift the chain up and over the teeth on the cam gear. No thanks!

[pastry_chef]

Originally Posted by gtofreek

Then why is it that every engine I tear down with a link belt setup, the chain is super loose.

Because that is what real engine builders see..