Machining a crankshaft in a 1987 740 GLE

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jamiebabineaux

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!
 
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!
Click to expand...
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
 
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?
 
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?
Click to expand...

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.
 
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.
 
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!
 
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.
Click to expand...

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


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.
 
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.

http://www.flickr.com/photos/jamiebabineaux/sets/72057594063523193/
 
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.

http://www.flickr.com/photos/jamiebabineaux/sets/72057594063523193/
Click to expand...


Hey that thing does look pretty good.

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.
 
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.
 
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.
Click to expand...


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.
 
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.
 
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.
Click to expand...


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.
 
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.
 
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