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Anyone put a gear-drive timing set on a BB?

Discussion in 'The Garage' started by chevyin, Apr 2, 2006.

  1. chevyin

    chevyin 1/2 ton status

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    Hey guys. Working on a 396 I pulled out of my chevelle to drop in the 73 K5 (bought a RJ502 for the velle). Just pulled the timing cover and discovered the chain is worn to the point I need to replace it before dropping it in the truck. So Im considering a gear-drive. The problem is Ive never installed one, and when looking into them, its said that "some machining may be required" to install them. Im guessing this is a clearance issue with the block? Is it a minor mod, like a dremel project, or is it more serious? Im not gonna tear the whole motor down to do some major block work, I'd just go with another chain set if that's the case.

    Anyone installed a gear-drive on their bigblock? Any info/opinions would be appreciated. TIA guys.
     
  2. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    It is minor work if any at all. The pete jackson gear drive is probably the easiest to install. I hope you like noise, after a couple days you will probably wish you hadn't installed one.
     
  3. ryoken

    ryoken Puppy Fabricator Premium Member GMOTM Winner

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    Not to drag this too off topic, but can the noise be attributed to the idler gears?

    The reason I ask is because when we run reverse rotation motors in the boats, they are set up with a gear set, no idlers (obviously to get the reverse rotation) and they are as quiet as a chain...

    I probably just answered my own question... :doah: :o :haha:
     
  4. chevyin

    chevyin 1/2 ton status

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    Thanks for the reply 4x4high. I don't mind noise, and ya the Pete Jackson set is the one Im considering most.
     
  5. walla2k5

    walla2k5 1/2 ton status

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    The machining involves a possible clearancing of the idler "bone" to clear the timing cover.Shoudn't have a problem if you run a factory steel cover,but it may take a little grinding,filing of the spur on the idler gear.I have a Proform geardrive in my smallblock,no regrets.Hope this helps....
     
    Last edited: Apr 8, 2006
  6. chevyin

    chevyin 1/2 ton status

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    Yes, definitely helps, thanks. :bow: Unfortunately I already have a new aluminum timing cover, might have to hog out some material for it then I guess.
     
  7. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    With an aluminum cover you might end up with a hole through the cover, seen it done before.
     
  8. chevyin

    chevyin 1/2 ton status

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    Why would that happen? If anything the cast aluminum piece seems stronger than the stock sheetmetal cover I removed. Do you mean due to a more severe clearance problem or something? The aluminum cover is definitely thicker, of course.
     
  9. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    The cover is thicker and usually to the inside so now you have to grind on the inside of the cover as well as the gear drive pins.
     
  10. Muddytazz

    Muddytazz 1 ton status

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    Stronger yes, but with it being thicker, its also closer to the timing set
     
  11. chevyin

    chevyin 1/2 ton status

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    Ya that's what I figured (the issue of being thicker towards the inside). So... I guess my next question is has anyone put an alum cover on with a gear-set? lol I dont mind grinding the inside of the cover. Guess I'll try it and see what happens, I can always put the stock cover back on if I just can't get it all to fit.

    Thanks again for the replies guys.
     
  12. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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    WHIRRRRrrrrrrrumbleRRRRRrrrumbleRRRRRRrrrmblepop

    That's what some folks told me, but I like the hum/howl of straight-cut gears. The exhaust is fairly rumbly in a sharp kind of way, and so the two make a nice little mechanical symphony that starts the day with a grin for a grizzled old gearhead like myself.:waytogo:

    If a guy wanted less banshee-wailing under the hood, then a helical-cut gear drive might be right up their alley. Helical sets have the thrust button adjustment to set, but that shouldn't be too much of a hassle.
     
  13. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    I'm not sure why people like noisy things, and also something that can hurt your engine. Think about all the harmonics that are being transfered to the camshaft and distributor. Also, if you have an EFI system you cannot run a gear drive because the knock sensor will pick it up and the ECM will start changing the timing on you.
     
  14. Drey

    Drey 3/4 ton status

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    A Velle running around here has gear, it sounds like the damn thing has a supercharger on it
     
  15. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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    That's right, they can confuse the knock sensor (if you have one), and they do clearly warn about this for the EFI folks.

    I've tossed a timing chain once, many years back, on a built street engine - which resulted in valves through three piston domes (now there was some noise), and I've distrusted chains ever since, for over 20 years. I don't fully trust my NP203 chain, but if it shreds it won't destroy my engine, and will be far cheaper to repair.

    Gear drives cost more, and they are over-doing it for street use, but the chance of tossing a chain drops to zero (from nearly zero, admittedly).
     
  16. yellowK20

    yellowK20 Well Lubricated Premium Member GMOTM Winner

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    I have the ERSON geardrive(P/N E992006) in mine it's not AS loud as the petejackson it replaced But it is a single Idler with the timing cover and removable plate for cam timing adjustment Very cool setup with no machine work required (expensive though) It also has nearly no slop (about as much as a Quality Double roller chain) My Petejackson Dual Idler had a lot of slop.2-3 degrees worth of movement. I would say sell the Pete Jackson on E-bay and Buy a good double roller set.( the noise gets annnoying )
     
  17. chevyin

    chevyin 1/2 ton status

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    Some great info and opinions here... keep em coming guys.... Im still not positive which way I want to go with this. :D
     
  18. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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    I'd venture to guess that good double-roller chain sets are better than they've ever been. Certainly a tiny bit better than they were a couple of decades ago.
     
  19. 1-ton

    1-ton 1/2 ton status Premium Member

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    Another thing thing that might need to be machined is the engine blocks number 1 cam journal for a needle bearing type thrust washer, which goes behind the camshaft timing gear. With a stock factory timing chain and gear design you have the chain keeping the camshaft from walking in and out of the engine cam journals too much, but with a drive gear set up you have nothing stopping the camshaft from walking right out of the engine (except the timing chain cover pan, and that is not good). You have to have an adjustable thrust pin and thrust washer set up on a timing drive gear. The needle bearing thrust washer is about .0020 to .0025 thousands of an inch thick, and the number one engine block camshaft journal needs to be machined back by the amount of thickness of the needle bearing thrust washer.
     
  20. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    This is not true. Most gear drives do not use a thrust bearing and some not even a thrust washer because the distributor keeps the cam in the block being pulled backwards into the block.
     

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