Main bearing change

[Peter Cresswell]

Hi Steven
Firstly - sorry I don't know what the thread in the main bearing caps is - I just found a bolt that fitted, but it suspect it will be UNC.

To undo the flywheel bolts, first you need to immobilise the crankshaft so that all the force you put on the bolts goes into trying to undo them. As you have the engine apart this is relatively simple. Wedge one of the crank webs with something against the side of the block - the handle of a hammer works fine, but make sure it is against the side so when you try to undo the bolts holding the flywheel in place it doesn't revolve further. Then make sure the tab washer lugs have been folded back against the flywheel. The easy way to do this is to use a screwdriver and hammer to gently tap the lug away from the bolt until it is at 30 - 40 degrees. Then use a socket and strike it with the hammer until it is flat against the flywheel. Now you are ready to try to undo the 6 bolts. They are quite tight so a bit of persuasion might be needed. Firstly try a socket (6 sided are best for this) and a long breaker bar, the longer the better. Most important is the breaker bar goes across the centre of the flywheel. This ensures that most of the torque you apply goes directly into the bolts. You might find they release with this but if not try keeping the pressure on the handle of the breaker bar and use a lump hammer to provide a bit of impact action. This is the same as effect as an impact gun. If this fails, then I have used an old but still usable ring spanner and fit this to the bolt and belt the * out of the other end with a big hammer. Take a lot of care though because you will have to hold the spanner in place whilst to hit the other end. WEAR VERY HEAVY DUTY GLOVES!!!!!!!!!!!!
Just in case they have been Loctited, in try a bit (might be quite a lot) of heat from a butane blowlamp.
Last option, if they still fail to come out you will have to drill them out to get rid of the head and once the flywheel has been removed from the end of the crank, you might find the bit of the bolt just unscrews with a pair of molegrips!
Given the bolts may have been over tightened or treated with Loctite, buy new bolts, and don't forget to get a new flywheel tab washer. I can't remember if this is part of the tab washers set so check when ordering.

I have built dozens of engines in my time of fiddling with cars, and I have to say I have never had any success in putting new bearing on a worn crankshaft as the new bearings seem to fail very quickly. This may be due to all the bits of metal floating around inside the engine which you can't clean out unless you strip it down completely, but you might be lucky!
Pete

[Steven collins]

That a pretty comprehensive response Pete, many thanks, I will give it another attempt tomorrow. Is it possible to remove the other end cap without removing the timing chain/cover ? this is something I really do not want to do unless absolutely necessary.
Many thanks
Steve.
PS
I think that I am lucky in that there is no evidence of metal particles in the engine/oil filter/sump etc

[Peter Cresswell]

The only problem you will have (I think) is fitting a new seal between the bearing cap, the block and the front plate. The new one in the gasket set is too fat to fit because it is assumed the front plate will compress it into position as the plate is tightened down. You should replace the front cover and the big oil seal in the rear plate as a matter of course otherwise the engine will leak like a sieve. The one to use is the LDV Van oilseal for the rear, part No. LUF10002, irrespective of what comes in the gasket set. Peter Burgess now recommends an even better one!
Also of course it will be very difficult to replace the front main bearings unless you do remove the front plate.

[Peter Cresswell]

Quote "I think that I am lucky in that there is no evidence of metal particles in the engine/oil filter/sump etc"
So where have they all gone?

[Steven collins]

Read - particles as small visible flakes, - I’m sure there are particles unseen by the naked eye in there.