I have been looking at some of the Summit Racing timing sets that have a crank sprocket with 3 keyways allowing normal/4deg advance/retard of cam timing.

Anyone run a stock 455 with the cam timing advanced?

I understand that advancing the cam moves the power band lower, and it's low end I am after to get this heavy car to get up and go from a stop quicker. I don't want to have to take things apart twice though, so I was wondering if this is worth it with a stock cam.

Any opinions? Thanks.

 

I wouldnt do it, its not something you want to do driving around on the street. it could seriously affect your fuel mileage and driveability. i have a double roller timing set on my 455 with the same setup, and when i built the engine i dialed in the cam and actually had to install it 4 degrees advanced, to align the cam straight up. the cam out of the box was 4 degrees retarded. a 455 with good heads and cam will move any heavy car from a stop quickly

 

I don't think I will do it, not without knowing the specs of the stock cam. I don't know how much advance/retard Olds has built into their cams.

 

I build my own engines, and always degree the cams in, as have a wheel kit. Usually a few degrees advanced is a good idea for low rpm street engines. I wouldn't play with a stock cam, as may have some advance already built into the cam grind. Add in, most cams when installed are generally off a degree or two either way, so why I work with a degree kit and manufacturers cam card. If going with an aftermarket cam, good checking with the manufacturers Tech Line, as many have a couple degrees of advance built in, even when installed strait up. If you're not checking for dergee, I'd just install it straight up.

 

Advancing the cam does tend to move the torque peak RPM range down a bit. The earlier closing of the intake valve tends to increase cylinder pressure slightly.

For the most part, I install cams 2 to 4 degrees advanced. Even the double roller chains will stretch a degree or two fairly quickly. Most stock replacement sets for the 70's had a built in retard (for emissions) either in the timing set or the camshaft. That was another reason I advanced the cams. My 10.25:1 Buick 430 is run sraight up as it detonated slightly at 4 degrees advanced at the same ignition timing settings

Back in the mid 90's, I was rebuilding a Pontiac low compression 455 for my driver. I bought a 3 keyway morse timing set from Summit. Mounted the set in the 4 degree advance keyway and the cam was 13 degrees retarded. Tried the other two slots and the best I could get was 6 degrees retarded. Turned out the set was manufactured in India and that's all they had on the shelf in the morse style. Ended up having to spend a bunch more money for a roller set.

 

Some very good info here and also a contradiction of terms.

If you're installing a cam "straight up' technically that means that if it's ground on a 110 lsa that you're installing it on a 110 lca. As you know they are 2 different things. So if your cam is ground with advance in it then you are quite simply installing as directed if you install it with the advance intact. That's not straight up.

For the record I'm not sure how many times I've heard "engine builders" say they installed it "straight up" when in fact they're not really sure what the real cam timing is. All they did was align the dots and to them that's straight up. If that happens to any of you then grab your stuff and run the other way, quickly.

 

Always have the crank spocket set to regular. All aftermarket cams has already advanced a couple of degrees for timing chain stretch.

 

Mark, I know the Engle cams in my cars were ground with 4 degrees in them...do Lunati and Erson do the same?

 

Simply not true. Man I wish people wouldn't assume.

Steve, it depends on the grind. For instance if you look at the latest Lunati catalog you will see the following;

Grind 318A5 108/102 Ground on a 108 with 6 degrees of advance
Grind 50819 113/110 Ground on a 113 with 3 degrees advance
Grind 00084 110 Ground on a 110 with no advance (Need I say more?)
As a matter of fact Lunati has a lot of cams listed as having no advance whatsoever, Erson has a few too. So again please don't assume.

Thank you.

 

cutlassefi,
I use to work for a Pontiac specialist named Nunzi who grind his own cam. He uses Crower and he told me that he grinds his own cam a few degrees advanced. He even showed me a GM stock cam and his own cam while degreeing his engine and sure enough his cam was advanced.

 

O.k, so how is that all cams?

That was his cam, not all cams. I just gave proof otherwise. You clearly said all cams, reread your post please.

Again for all of our sake please don't assume and consequently state inaccurate info.

Thank you.

 

Wow, thanks for all the input guys. I appreciate it.
I do not have a degree kit unfortunately. So I guess there is no way to know exactly what my cam grind is? Does Olds have these specs out anyplace? Did they use different cams in the large cars like my Delta vs the more performance oriented Cutlass models?

So what I am gathering from this, if I don't know my cam specs, it's probably best to leave it alone.

What got me wondering about this is the car feels very sluggish at low RPM (coming off idle from a stop), but once its moving it feels very responsive, even at highway speeds. Maybe this is purely due to the worn timing gears and chain I have now though... or maybe it would like a little advance?

I used to think this low end lack of performance was just due to the 2.73 rear end, but after reading how most peoples high geared big cars perform, I think something else is wrong. Ignition stuff is new and I rebuilt the carb, ignition timing is advanced past factory spec, but I still don't feel like I have power from a stop. In fact, advancing the timing seems to have very little effect on performance, and only causes detonation once the revs come up. I can rotate the crank pulley about 1.5" before my rotor begins to turn, so I am thinking maybe a timing set is in order.

 

Uh, yeah! I think you will get your power back by just replacing the timing chain...how old is it again?

 

You don't need a kit.

All you need is a degree wheel, which you can make by printing a picture of one on a piece of paper and gluing it to a round piece of cardboard, and a dial indicator, which you should have anyway.

You'd be surprised at how few cams Olds made in these years.
You can check the Parts Manual, but I believe they used the same cam on all non-Toro and non-High-Po 455s for several years in the early '70s, regardless of other factors.
Just go trough the Parts Manual, cross out all the Chebby small-blocks in the X-bodies and the Pont. 400s, see what your cam number is, and see how many other places it appears.

You definitely need to change your timing set. You can worry about different cams after that.

- Eric

 

1.5" at the pulley (assuming a 7.875 dia pulley) is 14.5 degrees or equivalent to about one tooth on the crank sprocket. On vehicles I've driven that jumped one tooth, advancing the ignition timing made the engine seem almost normal except down low where they were a bit "soggy".

You will notice an improvement with off idle very low RPM response and torque with a new timing set, even if you set it straight up.

 

I'm not sure how old it really is, I've only had the car just over a year. It came with a ton of service and parts receipts beginning around 1988 and none mention any timing chain!

Oh yeah! I have heard of those print outs before, forgot about that. Thanks Eric.

That describes my engine pretty well, initial timing around 12 degrees, seems good while driving around. Once I come to a stop sign and have to get moving again, it feels like a whole different (much smaller) engine.

I'm looking forward to installing the new set, well, I need to buy it first. Next payday probably.

 

Eric, where can I find this Parts Manual you refer to?

 

You're kidding, right. No way I'd ever trust a makeshift degree wheel, when only talking a few degrees. The degree kit I have, has an aluminum calibrated wheel, magnetic dial gauge, piston stop, extended lifter, and bushing assortement. I always do this before the head install, and only want to do this once, before everything goes back together.

 

At WildAboutCars, of course.

Well, that's very nice, and very accurate, but all he's trying to do is make sure his cam is not way out, on a basically-stock motor, not tune a 9 second drag car.

He has nothing to gain from sub-degree accuracy, and does not need to have the extra $20 or whatever stand in the way of his making sure his cam is set right.

I can tell you that I have done this myself, and it has worked fine - if you visually confirm that all of the 360 hash marks are the same distance apart, then the wheel will be good, +/- a degree or so, which is just fine for the average guy.

Another alternative, which I have also done, is to make a degree tape to go around the balancer, and use the 0° mark as your pointer.
Once again, not perfectly accurate, but good enough to tell you if there's a problem.

- Eric

 

WHOA TAKE IT EASY MAN!! I'll go and call Nunzi, Crane Cams, Comp Cams, Summit and Mondello that they gave ME bad info. Is that ok with you?

 

Sure, you can do whatever you want. But if you really knew what you were talking about and you really knew what to make of the info in the catalog then you shouldn't have to call anybody.
Whatever.

Jmo