Ok, after recently replaced the main bearings in this small clock chevy, I have a huge problem with this damn belt drive gear. Comp claims that the puller holes were either 5/15 or 1/4-20. After figuring out what the hell they really were, I discovered that it was 12/24 threads . OMG... Now comp claims that they really dont know for a fact what they are tapped for. Their tech support is TERRIBLE...So after searching for 12/24's that are 3 to 4 inches long ( good luck finding them ) I found some 3" ones with Phillips heads. I put the puller on it and pulled on this gear so hard, I was afraid that all the pent up energy from applying pressure to these little screws with the puller and an 18" adjustable wrench, I was getting nervous about it flying apart right at me. I put so much pressure on it, it was time to stop and back off. While I had all that pressure on there, I took a piece of .500 round brass and hammer and taped many times around the gear. NADA.. I have been soaking this joint with PB blaster for almost 2 months because I was afraid this might be an issue. I have been told DO NOT put heat on that crank snout. I have new seals in hand and I would hate to put the motor back in and find the seal leaking but I can change it if I cant get the damn gear off. This belt drive has been on there for 18 years. The reality is the motor is scrap in the future if you cant get the gear off. Im out of ideas. I would not attempt to drill those puller holes to 1/4 as there's a step in the gear by the holes and I would most likely break a drill bit off in there. Say the pics. Not to mention how close to the crank snout you are. I can get a new gear from comp for the low cost of $100 but honestly if I can get the damn gear off, im ready to scrap the gear drive and just put a chain on it. If I actually had 1/4 or 5/16 puller holes, I would be able to put hex head grade 8 bolts in the puller and give her hell with an impact. But, that's not an option. Comp has ZERO suggestions. Anyone have any tricks up their sleeve ?
Can you tap the gear back? Even if it is just a few thousandths it will break it loose. Then try pulling it. You may have to worry it back and forth until you finally make much progress
Well if you are ok with giving up on the drive gear you could try to weld a flange on the OD of the gear. You would then have a place to add threads or use the flange to pull against.
No, its driven up against the crank as far as it will go. The instructions for the belt drive say to drive it as far against the crank shank as it will go. Im sure thats what I did all those years ago. I have seen threads where people are talking about using a cold chisel next to the keyway and splitting a regular timing chain gear but im thinking thats not going to work in this situation.
The drive gear can certainly be replaced with a new one. this is the shittest design for removal that I've ever seen.
...or weld on a few threaded couplings which would give u lots of welding surface and push against the block.
I think that would make it smaller, not larger...??? But making the crankshaft colder, and the pulley warmer, would do what you want. Too bad they transfer heat to eachother. Can you pull the crank out with the pulley still on it? I can't really tell, but it might be possible. Remove the cam, pistons, rods, main caps, and the plate bolts, and see if t will move around enough to come off. Then you might be able to get a puller or press plate behind the pulley. Is the metal soft enough that you can redrill and tap the puller holes to 5/16 or 3/8"? Or just take a torch to the pulley, and ruin it.
Cold will shrink the gear, heat will make it bigger. Never messed with what you're working on, but is that a split setup on the gear? Are those these holes designed to push the gear off?
are you thinking it's one of these? But yeah, if the holes go through, they might be used to push the pulley off. (btw it's not a gear, it's a pulley. Gears mesh with other gears, pulleys are used with belts.)
I'd put the puller back on and use some heat on the pully. Not so much heat that would damage anything, just enough to relax the pully some on the snout. Apply tension to the puller to the point where you feel the need to stop before pulling out the screws, put some heat on the pully and tap on/around it with a brass drift to shock it enough to release. If that didn't work I'd get destructive on it.
The hub goes on the crankshaft, then the pulley goes over it with a tapered fit to compress the hub. Remove the outer pulley and the hub will be free. Possibly
What about using a cut off wheel to split the gear? I know it's tight, but I have used a Dremmel tool in the past with great success. It is slow, but it does get the job done. You appear to have quite a bit of room on the top side of the gear. I just looked at your picture again and I see tapped holes on the outer circumference of the gear. Can you use these to give you extra purchase for the puller? Have you tried using an air hammer to rattle the gear when you have the puller up tight? Just rattling against the outer circumference might break it loose.
No sir. they are blind holes according to comp but DAMN I need to verify that . I ran a start and bottom tap in there. Ck out the pics. LOL comp may have changed how they make it but from my past experience with them, I suspect they have the wrong pic up for the 6100 gear. the gear they are showing looks like the one that goes with the belt drive that has an idler pulley. And the gear is one piece as you can see
From the installation instructions. Im using an Eagle 4340 forged crank Crank hub installation – Remove the outer belt guard from the crank gear by loosening and removing the four button head Allen screws from the font of the gear. Set the guard and screws aside for reinstallation later. Install the lower gear with suitable soft metal driver like COMP Cams® Part #4920. Do not use just a hammer to beat the lower gear on. Severe damage to the lower gear may result from doing so. Make sure that the crank gear goes all the way on the crank up against shoulder on the snout. Some cast cranks have an extremely generous radius down to this step that prevents the gear from going all the way back against the step. Provisions must be made to eliminate this potential interference if it exists or belt misalignment will occur.
You'd think that the hub gears would be blind, but the holes in the pulley would go through. I'm sorry man. I wouldn't be afraid to throw some heat on the hub. The heat cycle isn't gonna hurt the crank.
those other tapped holes you are seeing are 10/32 and they hold the belt guard on. its just a metal ring to keep the belt from running off the gear
I've been looking at the pictures ,and reading this for a while. I'd put the puller back on, snug it up, and then heat the hub/gear with torch. Even propane torch will help to loosen what might be making it stick. Let it sit. Tighten puller, tap hub/gear, try again. I ran into something like this a while back, the damper/balancer wouldn't pull off. Seems there was paint overspray on the crank that tightened up the press fit. Pressure, heat, and more pressure got it off. Keep trying, it should come off, eventually.
I've seen the LS guys heat their balancers with a propane torch to help get them on - I can't imagine you will hurt anything. If you aren't worried about ruining the gear you could use a cut-off disk and cut slots into it and use a 3 jaw gear puller.
Thanks, I'll go back at it. I dont have a lot of faith in the ability of those 12/24's to take the required stress to get that pulley off.
If you use a hotter torch, then the heat will not have time to transfer to the crank snout as the pulley heats up...giving it a better chance to come off, I think. We can blame Comp for calling the pulley a gear, I suppose no biggie
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