>--=_ORCL_17176410_0r0
>
>Hello All,
>
>I have a rover v8 with a knock that I suspect to be either main bearing or
>big end related. The rest of the motor is probably OK, ie CAM and lifters
>etc. The oil pressure is good when cold but the warning light comes on when
>hot idling. The knock is apparent under heavy load, for example in third
>up a hill. There are no noises at idle or revving in neutral. I suppose
>it could also be engine mount related, but the oil warning light leads me
>to think a main bearing.
>
>But as I am in the process of tidying a few things up on the car (which has
>quickly turned into a full rebuild :-) ) I would like to do a bit of a
>quicky on the motor and replace the bearings with it in situ. I have the
>sump off, and have had a bit of a play with the conrods and main bearing
>caps, unfortunately nothing is obviously loose. Sure this is a bit of
>sideways play in some of the conrod bearings, but maybe this is normal....
>I will be replacing all of the conrod bearings, but:
>
>1. Is it possible to replace the main bearings with the motor in the
>car (83
>Range Rover). Or at least some of them. I would plan on replacing them
>with standard sized bearings.
>I realise this would only be possible if the journals on the crankshaft are
>not damaged. But suppose they are, would simply replacing the bearings
>get me another 20,000 k's out of the motor? I have heard that it is
>possible to slide the top shells under the crank shaft. Also is it easy to
>get at the front and rear bearings, with their associated seals?
>
>2. The nuts on the conrod bolts are a weird shape, they sort of look
>like a
>TORX pattern. But I cannot find anyone that sells a socket to fit. Any
>ideas on where to get one in Melbourne Australia. Or even what their
>official pattern and size is?
>
>
>Thanks for any advice.
>
>Stuart
>
>--=_ORCL_17176410_0r0
>
>********************************
4/28/99
Stuart,
Here are some tentative thoughts regarding your situation. I
cannot help nail down your diagnosis any more accurately. You can get at
least some idea of journal condition by removing caps 1 at a time (both
mains & rods) and visually inspecting what you see--also bearing shell
condition by looking at the half in the cap you remove. If they look OK,
you can get some idea of wear by using plastigage--It might not be
completely accurate but should serve as a good indicator. Bearings may be
available in .001" or .002" undersize to take up small wear amounts. Even
bad journals might benefit for a short time from new shells, but it sounds
to me like a pretty dodgy business to play that game, at least if both the
journal and old shell are rough.
I have seen over the years in various shop manuals and mechanics
textbooks pictures of a gadget designed to successfuly remove and replace
the upper half of main bearing shells one at a time, though I have never
used one. Basically the device is a short rod of proper diameter to fit
into the oil hole in the hournal, with a "head" to prevent it from slipping
all the way into the hole, and of a thickness a bit less than the bearing
shell. The idea is that, by placing this in the hole and carefully
rotating the crankshaft, it will rotate the shell out of the upper half of
the housing. OF COURSE, be careful you only try to rotate in the direction
that will bring out the end of the shell with the locating tang first.
Otherwise you will get a big jam-up as you try to flatten the tang out by
going the other direction. I'm thinking such tools might be available for
sale but, if not, might not be a big problem to make.
The con rod bolts you describe are unknown to me, so cannot offer
any thoughts thereupon. I'm sure others will add to this.
For what it's worth,
Regards,
Dave Kernberger
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