Machining a crankshaft in a 1987 740 GLE

Last night the mechanic got the engine out of the car and tomorrow night he should have the crankshaft out and able to be inspected.

The last diagnosis of the engine running was him using a stethoscope and believing that the "knocking sound" was the crankshaft knocking around inside of bad bearings. The plan is to remove the crankshaft and do a visual inspection.

I was told I might have my crankshaft machined and then use oversized bearings. I was told another option was to do an exchange and send my crankshaft in exchange for another one with bearings.

Has anyone done this before and what option did you choose? Also, we are estimating it would be around $100 to machine a crankshaft. Does this sound right?

Thanks!

Reply to
jamiebabineaux
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I did a replacement on a Plymouth about 25 years ago - IIRC it was cheaper than the machining and bearings, plus it came with a warranty as long as I replaced the oil pump at the same time.

Mike

Reply to
Michael Pardee

Thanks!

IIRC? I am not sure what that is

Reply to
jamiebabineaux

'If I Recall Correctly'

Reply to
Sam Smith

Thanks!

I have just been told that the crank looks pretty good and the bearings are "slap wore out." I'm going this evening to see first hand.

The early idea is to machine the crank to the first level (.010") and I assume replace the bearings.

My question will be, if the crankshaft bearings are worn, what else is secondarily affected?

Reply to
jamiebabineaux

I'd be curious what shape the rings, cam bearings, cylinder walls, etc are in. I've never seen bad crank bearings on a B230 so I have to wonder. Is the car a manual? If so then the previous owner may have lugged the engine regularly, pretty hard to do if it's an auto though.

Reply to
James Sweet

It's an automatic, and we live in flat country. Maybe because of the oil leaks for so long it ran low. The mechanic also said it looked as though it never had an oil change. That is hard (and scary) to believe.

He did say the bearings looked to have worn normally, with no signs of unusual damage. So, that's a plus.

Reply to
jamiebabineaux

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Per Hauge

Reply to
Per Hauge-Nielsen

Thanks, I called and they couldn't reference the B230F non-turbo, only the turbo and if by chance the 2 crankshafts are the same, he MAY have one, but none are showing in the warehouse.

If he finds one, it will be about $450 w/ bearings. So far I think I am looking at under $100 for the machined shaft and $45 for bearings to have mine redone locally, so I am leaning in that direction.

Thanks!

Reply to
jamiebabineaux

make sure you get the proper radii between journal and sides, otherwise the crank will break.

Reply to
M-gineering

The turbo crank is the same as far as I know.

That's a lot of money for a crank though, given it may have been run out of oil I'd really be looking for a low mile used engine, you can have new bearings and rings put in that if you like but normally just replacing all the gaskets and seals is sufficient. A motor that hasn't been abused is always a better start.

Reply to
James Sweet

I got to see the engine today, it wasn't in bad shape. Thankfully the bearings looked normally worn down and the crank wasn't bad at all. The local machine shop will charge $55 to machine the crank and the bearings will run about $45. Top that off with all of the seals, gaskets and timing belt stuff and we're at about a little over $200 for the whole works, plus $500 labor and that's about $700. Not too bad considering the first mechanic wanted $500 just to change the seals and timing belt.

At least now I know what I have. Oh, I am changing the engine wiring harness, too.

I'm getting happy! Progress!

Here are the pics - the exterior shots are in low light, I'll retake them.

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Reply to
jamiebabineaux

Yuck, might wanna clean up that engine block a bit while you've got it out of the car, that thing is gross. Some Oil Eater and a scrub brush could do wonders for it.

Reply to
James Sweet

Definitely that will be done. Thanks for the compliments. I haven't taken pics since I've stripped the tint, polished and waxed the car and detailed and cleaned the interior. I did clean the heck out of the engine compartment with degreaser, looks new.

I wasn't sure if I was going to replace the windshield soon, so I pulled the passenger seat out last night and got the headliner out of the car - in 3 pieces. :-)

Oh well.

Reply to
jamiebabineaux

May as well look for a replacement at a junkyard. I wasted several days putting mine back together when I broke it in half trying that same silliness, should have just gotten another one since that was a big pain in the ass too. As I said, it's just not worth trying to get it in/out without removing the windshield, even if you don't have it replaced, have a glass guy come remove and reinstall it for you, if you have a new headliner all ready then you could even pop it in while the guy waits so it only takes one trip.

Reply to
James Sweet

I bought two fiberglass resin kits and a big thick fiberglass mat. I have two layers of glass over all of the breaks, then I reinforced several corners. This thing is not breaking anytime soon again.

I am going to have the windshield replaced and when the guy comes I am going to slip it in and install the headliner while he puts in the glass.

I pulled the sunroof out and got that all cleaned up. I am still trying to figure out what was under the deflector shield,black thing. In each of the two front corners up on the lip, it looks like that deflector was either mounted on some type of molding or sealant, about 5" long. It's powder now, so I need to replace that.

Thanks.

Reply to
jamiebabineaux

When you go to apply the new cloth, you have to be real careful to get enough adhesive to bond it, but not so much that it soaks through. I would *strongly* recommend getting an extra foot or so of fabric and practice on something else, some sort of lumpy package or something. I also found that a hardback textbook was handy for smoothing down the fabric on the flat areas without pressing too hard. If you squish it too hard the glue will soak through and you'll end up with a permanent dimple.

Reply to
James Sweet

I am considering bringing the board and sunroof to the headliner shop and just have them apply the fabric. I can't imagine they would charge much just to do that, with me removing and installing.

The thing is my local shop only stocks 1/4", so I might have him do the board in 1/4" and then I use 1/8" for the sunroof.

I'm not sure. I'll contact the shop in Dallas which should have more options, I think my preference is to get 1/8" for everything if that is what is recommended.

Reply to
jamiebabineaux

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