[cnhorn63]

My motor is a '72 455 and has been running hotter than normal. I adjusted the timing to factory specs. Timing does not seem to be set correctly, advanced too far. I rotated the engine and located TDC with the #1 cylinder. The HEI rotor is pointing to the #1 cylinder. I assume that the notch on the harmonic balancer should be lined up with 0 on timing the cover. It is not even close to 0. Looks to be at least 6 degrees above where the timing marks begin on the cover. Just want to confirm that the Harmonic balancer rubber ring has slipped?

[Blued and Painted]

So your using some sort of probe in the spark plug hole to confirm TDC.

I like the replacement balancer's with the timing marks etched around the outer ring.
Makes it easier to watch your timing curve and valve adjustment is a snap.

[STEELCITYFIREBIRD]

Make sure mechanical advance is not stuck in dizzy.

https://www.youtube.com/watch?v=RENhHI9n65I

[TedRamAirII]

Setting your rotor to Number one just gets you in the ballpark. You will need to turn engine to #1 TDC with a small rod/dowel into the #1 Cyl and feel the piston come up until it stops and then go down, then turn it back until you feel it go back up, you will be able to find a happy medium , that will be TDC, maybe not exact, but close enough. Then look at your timing mark, if its not "zero" then the balancer has slipped, now make your own mark and thats your new TDC mark. At least you will be able to set your timing while you are waiting to replace your balancer. Most people would never know there balancer had slipped until they went adjusting the timing. When they check it "wow, thats way off" then they set it where they usually do, and it runs worse. Big red flag.

[cnhorn63]

Thanks for the quick replies. Yes, I used a straw as a probe to locate TDC in the #1 cylinder. I'm confident that I am in the ball park for TDC. The rotor pointing to the # 1 cylinder was not exact but close. Recommendations for a replacement harmonic balancer.

[gtofreek]

Pioneer and BHJ make good balancers, as well as others. I would stay away from Professional Products balancers though, as I have seen a lot of issues with them.

[t money]

I think it overkill in need and price without nosing anything about your comb but I have a SFI balancer in the for sale part of this forum if you what to look.

[Formulajones]

To check and/or make a new mark on the balancer, if you want it to be exact (and it really needs to be)

On an assembled engine you'll need a piston stop that screws into your spark plug hole. Very simple and cheap tool everyone should have in their toolbox.

Insert piston stop. Rotate engine clockwise until #1 piston touches, mark the balancer in this position, for example it may read 20 degrees BTDC.

Now rotate the engine counterclockwise until #1 piston hits the piston stop. Mark this position on your balancer, for example this time it may read 15 degrees ATDC.

What is exactly in the middle of those 2 marks is your new SPOT ON top dead center, which would be 5 degrees BTDC with the example I've given, which would show your balancer was off by 5 degrees.

I do this with every engine, usually during assembly while I am degreeing the camshaft,,,,,as I've had brand new balancers that weren't marked correctly or possibly the keyways are off slightly etc...You just never know with some of this aftermarket stuff. ALWAYS CHECK, cheap insurance and it only takes 5 minutes.

[Tom Vaught]

Originally Posted by Formulajones

I do this with every engine, usually during assembly while I am degreeing the camshaft,,,,,as I've had brand new balancers that weren't marked correctly or possibly the keyways are off slightly etc...You just never know with some of this aftermarket stuff. ALWAYS CHECK, cheap insurance and it only takes 5 minutes.

ASSUME will always get you into a lot of trouble.

KNOW lets you sleep well at night time and feel good when you put your foot into it.

Tom V.

ps If you verify that the balancer slipped toss it, it will continue to move from the time it first moved.

[cnhorn63]

Thanks formulajones and Tom, I plan on obtaining a piston stop to accurately determine TDC. Not a lot of info known about this engine, its an older build and prior owner did not know much either. Prior owner had the vehicle in storage 10+ years so very possible the rubber ring is done. Thanks for every ones input.

[Colin70TA]

I just finished degreeing my OLD faithful cam (which I had to advance 4 degrees to get at a 107.5 ICL). Confirmed top dead with a dial indicator. Went to install the timing cover and balancer and the TDC timing mark on my Pioneer balancer is lining up at 4 degrees before. Does this make sense? Should I just mark the balance to make a new reference to zero?
I am positive I did TDC right, took measurements on 0.200 on either side of TDC and recorded on degree wheel and found top dead that way.

[steve25]

Too much advance will absolutely not make the motor run hot, but a retarded setting of the timing due to the Balancer slipping , or a timing chain that it streched sure will !!

[STEELCITYFIREBIRD]

Originally Posted by Colin70TA

I just finished degreeing my OLD faithful cam (which I had to advance 4 degrees to get at a 107.5 ICL). Confirmed top dead with a dial indicator. Went to install the timing cover and balancer and the TDC timing mark on my Pioneer balancer is lining up at 4 degrees before. Does this make sense? Should I just mark the balance to make a new reference to zero?
I am positive I did TDC right, took measurements on 0.200 on either side of TDC and recorded on degree wheel and found top dead that way.

Dial indicator on piston, correct? Not thru timing chain.
If so remark zero, put a paint stripe or centerpunch on balancer hub to ring.... to indicate if ring ever shifts in future.

[Lee]

When you install the new damper, make a mark on the pulley to match up with the TDC groove on the outer ring. Then if the ring slips again, it will be obvious.

I saw a Summit Racing SFI damper for a SBC not too long ago, and it had slipped about 40 degrees.

[darbikrash]

Originally Posted by Colin70TA

I just finished degreeing my OLD faithful cam (which I had to advance 4 degrees to get at a 107.5 ICL). Confirmed top dead with a dial indicator. Went to install the timing cover and balancer and the TDC timing mark on my Pioneer balancer is lining up at 4 degrees before. Does this make sense? Should I just mark the balance to make a new reference to zero?
I am positive I did TDC right, took measurements on 0.200 on either side of TDC and recorded on degree wheel and found top dead that way.

Just did this degreeing in my stroker 400 using an OF 2 cam ground on a 112 LSA. I used a dial indicator as well, and found it about 4 degrees off. I messed with it for hours, and switched to a hard stop on the top of the cylinder bore to set TDC instead of the dial indicator.

Results within 1/2 degree. Put the balancer on and it was also within 1/2 degree.

The hard stop (metal strap across the cylinder bore with a bolt in the center as a stop) method is more accurate than using dial indicator, this is because at or near TDC the crank can rotate a few degrees with the piston not moving much due to dwell.

Try it with a hard stop and see if things change.

[Colin70TA]

Originally Posted by darbikrash

Just did this degreeing in my stroker 400 using an OF 2 cam ground on a 112 LSA. I used a dial indicator as well, and found it about 4 degrees off. I messed with it for hours, and switched to a hard stop on the top of the cylinder bore to set TDC instead of the dial indicator.

Results within 1/2 degree. Put the balancer on and it was also within 1/2 degree.

The hard stop (metal strap across the cylinder bore with a bolt in the center as a stop) method is more accurate than using dial indicator, this is because at or near TDC the crank can rotate a few degrees with the piston not moving much due to dwell.

Try it with a hard stop and see if things change.

Thanks, I was thinking that might be the case too because of dwell, which was why I didn't actually mark my measurements when the piston was 100% up but rather equal amounts on both sides of TDC. This gave me 2 readings on the degree wheel which I used to find true TDC. Now I am wondering if that's the correct way?
If that was correct then I'll just caulk up the balancer to machining or whatever and mark my new TDC on it.

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[Colin70TA]

Originally Posted by STEELCITYFIREBIRD

Dial indicator on piston, correct? Not thru timing chain.

If so remark zero, put a paint stripe or centerpunch on balancer hub to ring.... to indicate if ring ever shifts in future.

Dial indicator was on the piston

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[Lee]

You need the dial indicator right above the wrist pin. If you are at the top or bottom of the piston you will get errors as the piston rocks.

[Colin70TA]

Originally Posted by Lee

You need the dial indicator right above the wrist pin. If you are at the top or bottom of the piston you will get errors as the piston rocks.

Hmm, okay, didn't know that and not 100% sure where I had it. I have the heads on now, I'll check it again tomorrow with the heads on I suppose, see if I screwed up!

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[lust4speed]

The piston stop method works fine running up to the stop both ways since the slop in the system will be taken up when the piston jams against the stop and the error cancels out. When using the dial indicator you must do the measurements in the same direction on both sides of TDC. You would run the crank clockwise up to the .200" dial indication (or any other number you like), reverse direction but go past the .200" so you can sneak up on this measurement again going clockwise. When done this way, the dial indicator method is every bit as accurate as the piston stop method. Not taking measurements going in the same direction with a dial indicator will induce error in the amount of play encountered.