wrong balancer? - Team Camaro Tech
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post #1 of 7 (permalink) Old May 6th, 00, 12:01 PM Thread Starter
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This is kind of a continuation of my other post in engines & drivetrains, (compression problem). I think my balancer might be off. When my crank gear dot is straight up, and piston is top dead, balancer reads 8 degrees ATDC. I compared it to similar balancer I have (6.75") and the timing mark groove is different, by looking at keyway slot. Also, all the books & GM parts books say I should have a 8" balancer. I think maybe mine spun, but why would there be a 6.75 VS 8"? It's a 1967, 275H.P. 327. It should have a 8" I would think. And were is everybody? I need some input before I rip the cam out of this thing. Thanks.

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Steve
67 SS 396,4-sp
67 RS 327,4-sp
72 RS 350/350
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post #2 of 7 (permalink) Old May 6th, 00, 02:08 PM
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Bill
 
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Steve,
I don't recall ever having seen a 327 with an 8 inch balancer, but I could be wrong. There are however at least three different timing mark locations and that is probably where your problem is. I dont think the timing mark lines up with the crank keyway on any of them. I would bet that someone has switched the balancer, or the front cover / timing marker somewhere along the line.
Also, how are you determining top dead center ? Unless you have the head off and are using a piston stop or dial indicator, it is very difficult to determine exact top dead center as the piston "dwells" at tdc for a couple of degrees at least. Looking at the timing gear, or crank keyway is not accurate enough.
If you have the head on and can get the type of tdc stop that screws in the spark plug hole, you can determine tdc pretty close. YOu have to turn the motor over by hand until it hits the stop, then mark the balancer. Then turn the motor backwards until it comes around and hits the stop again and mark the balancer again. TDC is exactly half way between your two marks.
Hope this helps,

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Bill Koustenis
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post #3 of 7 (permalink) Old May 6th, 00, 03:10 PM Thread Starter
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Bill, your right about it being difficult finding true TDC with head on. I also thought 327's had 6.75" balancer, but a '97 GM parts book I have says 8". The timing mark on mine is lined up with keyway slot. I have a book that says the mark should be 2 degrees off of slot. Though I'm not sure how far over from slot that is. I understand what you mean about the piston overlap. But I thought lining the crank gear dot to the top would be accurate enough. When the cam was degreed a while back we used a piston stop to determine TDC. I assumed that if the dot was up then on crank, it would be now. I need to resolve this issue before I can acurately determine how far off my cam timing is . Thanks.

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Steve
67 SS 396,4-sp
67 RS 327,4-sp
72 RS 350/350
69 4X4 suburban 350,4-sp
73 3/4 ton 454/400
http://www.geocities.com/stevocamaro
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post #4 of 7 (permalink) Old May 6th, 00, 06:45 PM
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The 327 used the small damper, I had this engine in my 67 I bought new.
The timing mark should be two degrees from the keyway. This is hard to see unless you get a straight edge and line it up.
The 69 and later marks were moved 8 or 9 degrees advanced, counterclockwise looking at the damper from the front. This moved the timing mark closer to the water pump to be seen easier with the new long water pump. The power steering pump would have interfered with the old mark.
Motorhomes used a damper that had the marks straight up behind the water pump.
You have to use the correct timing tab for whatever damper you use. As long as it's not a 400 damper, you can swap whatever you like.
I'd go with the lighter smaller one, it will help the engine rev faster.
When you are right, the dot on the crank gear will be straight up, the timing mark on the damper will be at zero on the timing tab.
If you need numbers for the tabs I'll try to look them up for you.
Let me know.
David

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post #5 of 7 (permalink) Old May 6th, 00, 08:29 PM
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If you can get the marks on the timing chain to line up straight up and down, the cam is installed correctly. If it was 1 or more teeth off the marks will never line up. The only difference in degreeing a cam between different makes is the location of the number 1 cylinder, other than that its exactly the same. I'd say get a new mechanic. The cam could still be off if it is ground wrong. You need to degree it right. It's not that hard, but you do need a degree wheel, a dial indicator and a solid lifter. All the cams I have degreed from Crower or Comp Cams were right on. I think Comp Cams has a degree procedure on line. Also, their Xtreme Energy line is excellent.

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post #6 of 7 (permalink) Old May 7th, 00, 06:43 AM Thread Starter
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Thanks for responses guy's. I have a older chrome erson cover with taiwan indicater on it. I dug up factory cover & compared. I'm going with a new balancer, the rubber is bulged and I think it may have spun a few degrees. I just don't trust it. I will replace it with 6.75", your right dave, I always thought they had the smaller one, I just had to hear it I guess. I've had a few people here say the same thing as lonnie. It may be a bad grind on the cam. If that's the case I'll never be able to get it to run right. I have a cam in shop that came out of a '97 GM crate motor. It only had 4K on it before friend pulled it. It was in 300 H.P. motor, lift is 435 in. 460 ex. I can't remember dur. right now. I thought about putting this in as it would cost nothing right now & I can determine if the cam is the problem once and for all. I have the lifters that came out with cam, though not in order, with only 4K on it, I would think it's O.K. to just install & run them. What do you guy's think? Thanks.

Well, I just got back from shop, and guess what. I was getting ready to pull dist., to pull cam and the rotor is pointing at #7. DUUUUHH. I've been setting my timing all along to a spun balancer! And I think it was this way every since I got the motor back from builder 3 years ago. I don't know how it ran. Don't you think that's were my vac. went? And what about compression numbers, would timing that far off effect the numbers, I wouldn't think so but not sure. I'm thinking of just installing NEW, not rebuilt balancer & resetting dist. What do you guy's think? Thanks again.

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Steve
67 SS 396,4-sp
67 RS 327,4-sp
72 RS 350/350
69 4X4 suburban 350,4-sp
73 3/4 ton 454/400
http://www.geocities.com/stevocamaro

[This message has been edited by stevo camaro (edited 05-07-2000).]
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post #7 of 7 (permalink) Old May 7th, 00, 11:56 AM
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I took a cam and put new lifters on it. It went flat on one lobe. I'd either get a new cam or have yours re surfaced before putting new lifters on it. Putting used lifters on it without being in order is the worst choice.
Once the engine has run about a half hour the cam and lobes are worn in. Any changes in components from there will be risky.

The back of the Isky Cams catalog details several ways of indexing cams. Really good info.

I can't see how you could have it on #7 and have it run. That ring must have slipped a bunch. #1 & #6 are 180 degrees apart, so they are interchangable in that you could time the engine from either of those plug wires and the timing mark would appear the same. They just fire exactly 180 degrees apart. If you had the damper showing 0 degrees, it may have been at TDC of #6 cylinder?

David

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[This message has been edited by davidpozzi (edited 05-07-2000).]
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