Ah yes, I remember that situation now that you mention it. The timing chain kit was part of the comp cams cam package I bought.
CK5
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'89 R3500 Crew Cab 2wd to 4wd conversion & beyond
- Thread starter mrk5
- Start date
Started out with 2wd TBI350 with SM465 to current 4wd with 454, 700r4, NP241
what if you took .05 off the crank sprocket and .05 off the reluctor ?
The 58x kit that GM sells comes with a reluctor ring that is only about .10" thick. And it still requires you take about the same off of a stock Mark IV balancer.
The L29 must has to have an even thinner sprocket to have a .2" thick reluctor.
You could put the reluctor in the lathe or mill and turn it down only where it contacts the sprocket.
The Mark VI and Gen VI aftermarket timing chains are different, and it is mostly for the depth and clearing the cam retainer plate behind the cam sprocket. But the crank sprocket is different too because of that depth.
Another option is to get just the 58x wheel from GM, which is thinner by that amount and does clear the timing chain(though that was the special GM timing chain). The Holley will let you run a hybrid 58x crank wheel and 1x cam wheel. I wrote down those dimensions when I did it the last 58x conversion, I'll see if I can find them.
EDIT:
I found the thickness, the factory Gen VI 502 (Not L29) target wheel was .557 thick, the new one was .567 thick. So the Howards sprocket you have is no thicker than the 58x crank sprocket GM sells in the kit.
The target wheel is .088 thick where it sandwiches between the damper and timing sprocket.
I cut .098 off the 502 damper, but your damper is already .12" thinner than most BBC dampers.
I did have to clearance the block for the timing chain, so they may have moved the timing chain back to clear the target wheel...
The L29 must has to have an even thinner sprocket to have a .2" thick reluctor.
You could put the reluctor in the lathe or mill and turn it down only where it contacts the sprocket.
The Mark VI and Gen VI aftermarket timing chains are different, and it is mostly for the depth and clearing the cam retainer plate behind the cam sprocket. But the crank sprocket is different too because of that depth.
Another option is to get just the 58x wheel from GM, which is thinner by that amount and does clear the timing chain(though that was the special GM timing chain). The Holley will let you run a hybrid 58x crank wheel and 1x cam wheel. I wrote down those dimensions when I did it the last 58x conversion, I'll see if I can find them.
EDIT:
I found the thickness, the factory Gen VI 502 (Not L29) target wheel was .557 thick, the new one was .567 thick. So the Howards sprocket you have is no thicker than the 58x crank sprocket GM sells in the kit.
The target wheel is .088 thick where it sandwiches between the damper and timing sprocket.
I cut .098 off the 502 damper, but your damper is already .12" thinner than most BBC dampers.
I did have to clearance the block for the timing chain, so they may have moved the timing chain back to clear the target wheel...
Last edited:
The down side to taking it off the crank sprocket would be loosing the cam timing marks.
Is it possible to get just the 58x target wheel? All I found was entire kits.
Do I really need the double roller, or will the factory timing chain be good enough?
Yes I would take it off the reluctor side. If you took it off the block side it would change cam sprocket alignment
A good machine shop could add the timing marks back on with a laser engraver.
I wouldn't take it off the crank sprocket, no reason too. Just make the target wheel and/or balancer thinner.
I had written down the numbers, but now they changed the kit part number.
The previous part number for the target wheel was 19256786, but it says discontinued.
That was for the old 19370171 58x kit, the new 58x kit, 19260247, I don't have the target wheel number for.
However, that target wheel has a recess where it contacts the crank sprocket.
I think, if possible, I would just take it off of your target wheel, and be done, it's not a wear item. Just make sure the timing chain doesn't rub on the back.
And, you don't need the double roller, but it will give you more accurate cam timing, I've measured 3/4 of a degree of slop in a brand new factory timing chain.
Also, don't forget that you still have the valvetrain completed, so don't be turning the crank over with the cam stationary, it could bend a valve if you aren't careful.
No worries there, I get super paranoid about that stuff. Believe me, it's a big step just taking the timing chain off, let alone messing further with it.
I've got a co-worker with a small mill and he's going to shave down the reluctor wheel for me.
I've got a co-worker with a small mill and he's going to shave down the reluctor wheel for me.
Got the reluctor cut down. Absolutely could not take more then .1" off.
Tiniest bit of daylight.
Haven't checked pulleys yet, but I like the alignment on the sensor hole much better now.
Tiniest bit of daylight.
Haven't checked pulleys yet, but I like the alignment on the sensor hole much better now.
them rollers on the chain look like .................................... SH!T 
You might want to put an ever so small bevel on the back side of the target wheel, just to get rid of the sharp edge where it could ever contact the chain.
them rollers on the chain look like .................................... SH!T
His camera has some nice resolution, that's probably just closeup marks from the tumble polisher after chain link stamping, they usually look great in person, but it would be an interesting comparison of different quality levels, that is one of the better chains on a billet timing set, but not the best chain they offer, those get quite expensive and are unnecessary for most.
We have so much trouble with customers proofing 4'x8' signs on their tiny phone screens.
So close but didn't quite succeed.
I ended the day with the engine back on the stand. I'm having some consternation getting the right balance between lift height and the leveler clearing the cowl area. The crane just barely has enough lift.
I might have to bust out the forklift but it's more difficult to use solo. I did realize later after I went home for dinner that I was being a little dumb. The furthest point on the boom is 1/2 ton.
I got it in my head 1/2 ton was 500lbs so I couldn't use that spot. It was quite the epiphany when I realized it's 1,000lbs!
So that should help me succeed today.
I ended the day with the engine back on the stand. I'm having some consternation getting the right balance between lift height and the leveler clearing the cowl area. The crane just barely has enough lift.
I might have to bust out the forklift but it's more difficult to use solo. I did realize later after I went home for dinner that I was being a little dumb. The furthest point on the boom is 1/2 ton.
I got it in my head 1/2 ton was 500lbs so I couldn't use that spot. It was quite the epiphany when I realized it's 1,000lbs!
So that should help me succeed today.
I put the smaller rollers on. Drops the vehicle height and provides better access.
I definitely had tunnel vision yesterday. Didn't even think about pulling tires off. When I left I thought about working later but decided I needed to take time away. Obviously I was right. I had gotten stuck trying to make what I was doing work.
We have all been there.
