Cam Timing Fun

Old January 11th, 2019, 08:23 AM
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Cam Timing Fun

I'm trying to degree the cam in my '70 350 that's going into my 1991 OCC. Spec sheet shows 110 for the center of my intake lobe. The best I can get is about 105.5 or 112. I'm using a Comp Cams double roller timing set with 24/48 teeth and 3 keyways with supposedly a 4 advance or 4 retard, but even when clocking the crank gear and skipping teeth, I haven't been able to get any closer.

This is a big heavy car, building for cruising/hauling not high RPM racing. This cam is a hydraulic roller, 1000-5000 RPM power band "RV" spec. The cam card says 110 intake on a 108 centerline so it already retarded 2, so for this install I don't think I really want a total of 4.

So, here's the question: Do I go 112 and get a little extra top end, 105.5 and get a bunch more bottom end, or drill the cam gear and use a bushing to get it to 110? If it were 108, I'd leave it. Maybe I'm just worrying this thing to death... is 2 really worth the effort?

Last edited by Dr. Oldsmobile; January 11th, 2019 at 08:25 AM.
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Old January 11th, 2019, 11:24 AM
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Without seeing the cam card, I would guess a cam that is cut with 2deg retard on a 108 LSA, is probably a rather short duration cam.
Most tend to advance them, also taking into consideration that as the timing chain stretches over time, it retards the cam.

I used a bushing in the cam gear to get mine adjusted 2 deg, but you may also be able to find an offset key way for the crank.
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Old January 11th, 2019, 12:31 PM
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110lsa on a 108icl is 2* advanced, not retarded.
I quit using the Comp Cams 3 keyway timing sets years ago cuz they're junk. they don't even make them themselves.
If you're coming up with a 105.5* icl then leave it. By the time the chain stretches it'll lose a degree or so. And with a cam that small you really won't see the difference anyway.
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Old January 11th, 2019, 04:33 PM
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Curious what are specs on the cam and motor?
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Old January 11th, 2019, 05:58 PM
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How exactly are you degreeing it ? Are you using a lifter or some other tool in the lifter bore ? Just for grins instead of finding ICL see if the opening and closing points match up with the numbers on the cam card.

Personally if it is supposed to be at 110 I would want it at 110.
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Old January 11th, 2019, 06:18 PM
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I havent checked any other points yet. I know these Comp sets are notoriously wonky, but Ive been trying different clocking & tooth skip arrangements to get the intake as close as possible first.
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Old January 11th, 2019, 06:23 PM
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Alright, this image management from my phone is a bit goofy. Apologies if the photos are loaded in multiples...
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Old January 11th, 2019, 06:34 PM
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Originally Posted by olds 307 and 403 View Post
Curious what are specs on the cam and motor?
Ill try again.... 70 350, 9.5:1, forged pistons, mildly ported #6 heads, TBI.

Big heavy B-body wagon, stock 700-R4 trans.
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Old January 11th, 2019, 06:44 PM
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Interesting tool. Is the end that hits the cam flat or rounded ? The one I have has different "inserts" for flat tappet and roller cams. The one for the rollers has a rounded end. It probably doesnt matter in finding the centerline but it definitely matters when checking opening and closing points. Try it with a lifter and see what you get.

When I did my Wife's 307 I got a Crane custom grind Hydraulic roller and it degreed in perfectly with a Cloyes stock replacement timing set.

This is what I have but I try to use an actual lifter if possible.


Last edited by BillK; January 11th, 2019 at 06:46 PM.
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Old January 11th, 2019, 06:45 PM
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Use an actual roller lifter to make sure the contact points are as they should be.
Again if it's at 105.5 leave it. At that setting you're only an additional 2.5* advanced. It's a small cam, it won't make any noticeable difference. You sure it's a Comp? By the cam card I'm guessing it's an Engle?
Next time buy a better timing set though.

Last edited by cutlassefi; January 11th, 2019 at 06:50 PM.
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Old January 11th, 2019, 08:19 PM
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The cam is an Engle, the timing set is Comp.

Tool is square ended. Not much to run on with a lifter, but I get the same measurement.



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Old January 11th, 2019, 09:15 PM
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The BTR timing sets are very nice, and they have a cam timing gear with lots of adjustments, well worth the money if you want to get it spot on while you are at this point.

I have also seen issues with the comp cams set.

The only timing set I have ever seen work correctly is the BTR one in our engine now, and the Cloyes True Roller sets, all of the other ones from reputable and big name suppliers were always off. Also, I don't like using the bushings, as I did that once to correct a bad timing set, and even with peening the bushing in, it didn't stay correct.... You would have to tack weld it to get it to stay.
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Old January 11th, 2019, 10:09 PM
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Originally Posted by Battenrunner View Post
The BTR timing sets are very nice, and they have a cam timing gear with lots of adjustments, well worth the money if you want to get it spot on while you are at this point.

I have also seen issues with the comp cams set.

The only timing set I have ever seen work correctly is the BTR one in our engine now, and the Cloyes True Roller sets, all of the other ones from reputable and big name suppliers were always off. Also, I don't like using the bushings, as I did that once to correct a bad timing set, and even with peening the bushing in, it didn't stay correct.... You would have to tack weld it to get it to stay.
lol... I was going to buy a set from Bill, but he didnt answer the phone when I called, so I bought from Dick who had it in stock.

As far as I can tell, the BTR set is the same as Ive got, just with extra holes punched in it. When I build the 403 for my Riviera, I guess Ill know better.

Ive literally spent a week jacking around with this cam. I want to show the car at the Olds Nats this year, but that ain't gonna happen at this rate. I finallized the install tonight and Im moving on. A bit disappointed, but I gotta keep moving. Hopefully Ill have the pan & heads on tomorrow...
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Old January 12th, 2019, 05:10 AM
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Next time you ahould try a Cloyes 9-3513x9. Good set and not a lot of money.
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Old January 12th, 2019, 06:10 AM
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Originally Posted by Dr. Oldsmobile View Post


Ill try again.... 70 350, 9.5:1, forged pistons, mildly ported #6 heads, TBI.

Big heavy B-body wagon, stock 700-R4 trans.
What year wagon and what gear? Also what does your converter stall at? Should be a nice combo.
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Old January 15th, 2019, 05:49 AM
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Originally Posted by olds 307 and 403 View Post
What year wagon and what gear? Also what does your converter stall at? Should be a nice combo.

It's a 1991 OCC. Stock converter & transmission. I honestly have no idea what the axle ratio is. The sticker is so faded that I can't read it. The PO said the rear end was suspect, so I've been planning on going through it/replacing it anyway. I was originally building this for towing, so I was thinking 3.23 or 2.93. It will also be the wife's daily driver...
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Old January 15th, 2019, 09:47 AM
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The stock 700R4 converter can vary a lot. I would consider a 2000 stall especially if your converter stalls around 1400-1500 rpm, pretty low for the compression, cam and especially if it has 2.93 gear. A 3.23 gear would work decently with that heavy car but a 3.42-3.90 would work better.
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Old January 15th, 2019, 10:11 AM
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Originally Posted by olds 307 and 403 View Post
The stock 700R4 converter can vary a lot. I would consider a 2000 stall especially if your converter stalls around 1400-1500 rpm, pretty low for the compression, cam and especially if it has 2.93 gear. A 3.23 gear would work decently with that heavy car but a 3.42-3.90 would work better.
Right now, I just need to get it moving under it's own power so I can get it in for paint. The plan is to go through the trans & rear both before it goes into daily service, but my number 1 priority is to get it show ready for the Olds Nats this year. Nobody will notice the wrong converter or gears on the show field... lol

Tow package axles for these TBI cars were 3.23, and 2.93 for the later cars. Since I expect this Olds to do better than the crummy SBCs they used back in the '90s, yer probably right, but I'll see how the current drive line behaves behind a real V8 before I make any engineering decisions.
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Old January 15th, 2019, 02:47 PM
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I agree even stock low compression Olds V8's did better than the late 70's and swirl port sbc. Sounds like it will be a nice cruiser. Go with the better adapter plate, I went with a cheap one on my 94 Z71 with the Olds 350 to the 4L60E. Get this one.
https://www.summitracing.com/parts/trd-0061/
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