Save your engine tip

[Argess]

If you have one of those harmonic balancers with the timing mark(s) engraved, stamped, etched, whtever, on the outer ring, put a little mark of white paint on the outer edges of the front pulley next to the TDC mark. The pulley is fastened to the center hub of the damper and can't slip.

The stories about the outside damper slipping are true. Mine was slipping a little bit at a time, and every time I adjusted the timing, I was unwittingly adding in advance. Eventually, I broke a piston due to detonation. Checking the damper against a new one, I found it was out by 30 degrees. Amazing the engine even started. I checked the new damper against the engine with #1 piston at TDC and it was correct. Next came the white paint.

With the paint, if the outer ring slips, you'll see the difference between the painted mark and the TDC mark and know it's time to replace the damper. Plus you can use the paint marks to time your engine while waiting for the new damper to arrive.

Note 1: My enigne was an FE, but I think this could apply to most engines.

Note 2: You can buy dampers with a sheet metal cover that has the timing amrks on it, yet is fastened to the center hub of the damper and can't slip.

Note 3: Prior to putting on the paint mark, it may be wise to check your damper is still accurate with a piston stop or other method.

[patrickt]

So much for a slipping ring... and now speaking of valve timing, I asked a fella last week how his cam was installed. He didn't know, but wanted to. He was fairly certain it was an old style, single pattern cam. He also did not want to go to extraordinary lengths (like putting a lift gauge on his push rod, or even using a piston stop for that matter); a half-a$$ measuring job would do this time. Sooooo, I told him to remove his valve cover and, on the number one cylinder, rotate the engine until the exhaust valve just started to come back up to close itself. When it did that, lay a flat pencil across the intake valve and the exhaust valve and continue rotating the engine so now the intake valve will begin to go down into the open position. When the pencil is flat, indicating both valves are at the exact same height, read the timing mark on your dampner and that will indicate the advance or retard of the cam installation. For some reason, your post just brought this to mind -- and there just might be somebody out there that would want to check where their cam was after they checked the accuracy of their timing marks. Here's a graph of my cam, as installed, and you can see the "crossover point" is the degree of advance that I have.

[kitcarbp]

Argess,

For the rest of us folks here a little more detail in the failure would be helpful.

Was this a tired 30 or 40 + year old damper or was this some aftermarket relatively new part ? I am tring to understand if its a part quality issue (so others can get a heads up) , or a dry-rotted, aged, shrunken dampening material in the balancer ? In other words do you have an idea as to the root cause ? The reference marking idea is good and will help others monitor the damper if slippage begins to happen. Sorry you had the detonation failure, that just plain sucks.
Bill

[Argess]

No, not a quality issue. Just an age issue. It was a Ford damper and probably manufactured in the 60s or 70s. The rubber looked good with no cracks and the timing marks checked out fine when I originally put it on. But over time, the rubber must have shrunk or otherwise lost its adhesion and the outer ring started slipping.

Even new balancers can have this happen. ATI, for example, does offer a 10 year warranty, however they also go on about how a benifit to one of their dampers is that it's "rebuildable". Nothing to rebuild except the rubber......so caution is in order.

It was me re-setting my timing to the new slipped marks that caused the trouble, not the actual damper itself as it is a zero balance unit.

It ticked me off because:

1/ I ignored the warning signs once I had checked the timing and saw it was "fine".

2/ Only 1 piston was damaged, but they were FPP custom made units and I couldn't get another to match, so a whole overbore was required. A shame as the cylinder was not hurt.

3/ Interestingly, with the tons of smoke bellowing out one side pipe, a compression check showed exactly the same results in all cylinders. Only a leak-down check showed 1 cylinder as being bad. And it was ....top ring OK, second ring broken, ring land between 2nd ring and oil ring had over 1 inch broken out of it and oil seperator ring was in dozens of pieces, mostly in the oil pan. I will not use Hastings rings again due to that oil seperator falling apart. Plus, the engine always smoked a little bit. Since the rebuild, no smoke at all. I totally suspect this is due to Speed-Pro rings.

[Ralphy]

In my younger days I worked as a mech for a heavy equipment company. We had a crane that we used in the yard pretty much full time. Out of the blue they had it rented, the problem was it popped and backfired. After messing with wires , dist., etc... I finally pulled the #1 plug and stuck a screwdriver in the cylinder. The timing mark was off at least 10 degrees. So I guessed TDC and marked the harmonic balancer. Timed it to the mark, fixed! They never did replace it, just ran it that way.