hey everyone, new to the site. i've got a quick question. i have a'74 292 in a '77 chevy crew cab (not by choice) but i'm starting to like it. i put an hei distributor on a few months ago and i didn't have the timing set right because it was sucking gas bad. so i took it to a shop to have it set. long story short there was something wrong w/ that dist. so i put the old points back in, he goes to set timing and can't get it right because the harmonic balancer/ timing mark is slipping. is that possible? i looked at napa and they don't show a h/b for this engine. is he trying to dupe me for $200? sorry so long, thanks in advance for any info.

Very common and more so than some other engines. The material (rubber?) between the outer ring and the hub dries out.
I had one outer ring fly off on the freeway and another just drop to the ground when I started the engine.
On this engine the belts give the outer ring a good tug everytime the engine is started. On an engine like a SBC, the belt pullies are in front and bolted to the hub of the HB.
Even before I added AC, I mounted an unused pulley to the front to trap the ring from coming off and going through the radiator.

more so than some other engines

X2 - my experience as well. Once the rubber begins to go away, the ring shifts on the hub and the vibration gets worse, which shifts the ring again...
Giveaway: if the engine won't time on the mark (engine either knocks or feels very lazy with bad idle and response), the ring may have moved.

I got my new balancer from rockauto.com for about $65 +s&h.
Try looking up a Chev, 1975, P30 Van, 4.8l, engine, balancer

Where is the timing tab on your cover? Driver's side of center or passenger side? You can establish a new one at TDC if you need to but if your outer ring is slipping on old, dryed out rubber then it won't help for very long!

thank you guys for info. my timing mark is on the dr. side. now mech. is saying the timing gears are warbled out and the best way to fix is a new crank. he is going to temporary fix the gear. the price on labor would be more than the truck is worth. would replacing that ring make any difference or help any? thanks again.

Unless it's obviously damaged, the ring isn't the problem, and in any case there's no way to replace it without destroying the rubber.
Unless the gear moved on the crank you don't need a new crank.
I think this guy has decided not to let you escape without making X dollars, and he doesn't care how.

i am starting to get that feeling!! thanks for the help gents.

New crank??? I'm missing something. Are you saying the woodruff key on the snout has failed/damaged the crank? Or just need a new gear set?

Anyway, back to the HB, you can have yours rebuilt with new elastomeric for about $100. Damperdoctor or others on the net.

Mark your own timing marks if needed. Establish TDC with a positive stop tool in the spark plug hole and make your own timing marks using the stock or a homemade pointer.

If the woodruff key on the snout is screw up, they are more previlant on a 6 than most think, you can have a crank shop cut a new groove 180 degrees out and every thing will still match up.

Don't ever trust a timing mark....Do what was said above; screw something in the spark plug hole and hand crank until it hits. Make a mark on the the balencer. Rotate the crank in the opposite direction until it stops again. Make a second mark. Split the difference and that is TDC.

Good Luck

The other balancer rebuilder is Dale Mfg, in Salem, OR- a one man shop.

when i was told he couldn't set the timing because the gears were warbled out i took it to mean the the key had snapped or something else. he said the only way to really fix it would be a new crank. isaid it wouldn't be worth it, so he jb welded the gear in place w/no guarantee it will stay in time. would you be able to see the gears are bad by just pulling off the harmonic balancer or are they under the water pump cover? he said he added a w/p cover gasket to my bill but it was never removed.

I don't bad mouth much-BUT- I think you need to find a shop more familuar with these engines. J B WELD?????? JMO 1 OL DERNECK

I agree - I've heard of JB success in things I would not have tried (and still won't).
But... very few people spend their own time telling people how they did it, and lost the engine.
The twisting force between the damper hub and the crank is very large, even the key isn't enough. It's supposed to be a press-fit. If it moves, the damper doesn't work - and it eats the nose.

are the gears under the water pump or visible when you remove the damper? i'm wondering if he even saw them, because the water pump looks like it was never touched. thanks for the advice and info.

'nother possible "Now, what am I gonna do with that 292 crank some guy never picked up...?"