quick question before I drill crankshaft

[lutzTD]

I have everything ready to drill the dowel holes fro the front balancer, but the old holes are so bunged I cant get the orientation to my liking. its so bad it could go either way at 180 degrees. how can I set the engine to TDC without removing the #1 injector or glow plug? I can see the cam through the oil fill hole, is that enough

[junqueyardjim]

Things can go south in a hurry when drilling on a crankshaft. You really have to figure this out correctly, cause if you don't, you will be buying a crankshaft and more. Now I can't tell you how to drill it, but I do know those holes are not 180 degree apart. That we do know, and you will then have to figure out the correct line up. They are close to being 180 degrees apart, but only close. I think I would try to get it right by sticking drill bits in the holes, drills that are very close to the size of the pins.

[lutzTD]

Originally Posted by junqueyardjim

Things can go south in a hurry when drilling on a crankshaft. You really have to figure this out correctly, cause if you don't, you will be buying a crankshaft and more. Now I can't tell you how to drill it, but I do know those holes are not 180 degree apart. That we do know, and you will then have to figure out the correct line up. They are close to being 180 degrees apart, but only close. I think I would try to get it right by sticking drill bits in the holes, drills that are very close to the size of the pins.

holes on the crank are too torn up too be useful for alignment. ive had it on both ways and it doesnt look good either way. I made a fixture to redrill 90 degree off, I just need to have it in the right position before I drill. the motors junk now if I dont redrill so redrilling is not that big a risk

[lutzTD]

looks like I need to pull the valve cover tomorrow, I will set by the cam and tower mark.

[jt20]

[jt20]

does that help? In the first pic, the first lobe is centered on the camshaft mark.

[lutzTD]

I was trying to figure out how the marks work. so I need to eyeball the cam lobe centered on the cut mark on the left of the stand in your picture? or is the black part with the mark to the right the stand and the silver part with the mark to the left the cam?

[jt20]

yes.

your balancer should be close-ish to the 'OT' mark if that lobe is lined up-ish with that mark.

mplafleur has a much better picture of this if you can find it in one of the many "help me time my engine" threads. You'll get a better sense of the direction that lobe is pointing in.

[lupin..the..3rd]

Quite frankly, this is not a DIY task. If it were me, I'd pull the crank and take it to a machine shop. It's not that much work to pull it (and you can put new crank bearings in when you reinstall it).

A machine shop can fix the original bunged up holes using time-serts or helicoils. It'll come back like new without any new holes being drilled. Drilling new holes into a crankshaft introduces stress risers that could cause the entire thing to fracture apart later on down the road.

You could also have it mic'd and magnafluxed at the same time, to make sure it's even worth repairing.

[bigblockchev]

I feel your pain, spun pulley is a pretty serious problem. If you can stand the timing being off a few degrees then using the valve train to locate TDC is probably fine. If you want it accurate forever then you will have to locate the piston mechanically somehow. I have used a wire or screwdriver through the injector hole in VWs to do this but I think the prechambers would get in the way. If you could pull the pan you could get at it from the bottom. If you get really creative you could use one of the valves as a position indicator. This would mean pulling the cam and one lifter. Removing the valve spring would be the hard part but if you do it correctly you can put a dial indicator on top of the valve stem and let the valve follow the piston up the last few mm. This approach would be 100% accurate but technically quite difficult. How accurate do you want to be. Cheers Dan

[kerry]

Originally Posted by lupin..the..3rd

Quite frankly, this is not a DIY task. If it were me, I'd pull the crank and take it to a machine shop. It's not that much work to pull it (and you can put new crank bearings in when you reinstall it).

A machine shop can fix the original bunged up holes using time-serts or helicoils. It'll come back like new without any new holes being drilled. Drilling new holes into a crankshaft introduces stress risers that could cause the entire thing to fracture apart later on down the road.

You could also have it mic'd and magnafluxed at the same time, to make sure it's even worth repairing.

Some kind of misunderstanding in this post. He's not drilling bolt holes. He's drilling the holes for the pins that lock the pulley to the crank nose.
Pulling the crank is a hell of a job since it requires pulling the engine. Drilling in place has been successful before and it's definitely worth a shot in this case before pulling the engine and crank.

[lutzTD]

Originally Posted by lupin..the..3rd

Quite frankly, this is not a DIY task. If it were me, I'd pull the crank and take it to a machine shop. It's not that much work to pull it (and you can put new crank bearings in when you reinstall it).

A machine shop can fix the original bunged up holes using time-serts or helicoils. It'll come back like new without any new holes being drilled. Drilling new holes into a crankshaft introduces stress risers that could cause the entire thing to fracture apart later on down the road.

You could also have it mic'd and magnafluxed at the same time, to make sure it's even worth repairing.

Im a toolmaker, I am quite sure I can drill two dowel pin holes. if it doesnt work, then I will pull the moter and replace it. but if I have to replace it anyway, shouldnt I give it a try? the original holes are so bunged I cant even tell if Im lined up. I made a drill fixture to locate and maintain axial parallel. I drilled the holes but I found I did not have the correct reamer so I am waiting for brown. should be back together wednesday good as new

rest of the story here

bummed.... engine running but accessories not turning. 1982 300CD Turbo