crankshaft tight

Post by **wishbone** » Mon Apr 09, 2007 7:39 pm

I'm rebuilding my 1098 engine, rebore and all. I bought a reconditioned crank and + 10 bearings from esm. I fitted it today and it seems tight. I should say that this is my first bottom end rebuild so i'm not too sure how hard the crank should be to turn. I have no pistons and rods on. I cleaned all parts and applied plenty of oil. As I tighten down the caps the crankshaft goes stiff. It takes both hands on the crank and alot of pressure, or a big spaner on the crank nut. Its the same with or without thrust washers fitted.

What would be a good way to test how hard it should be to turn?

Post by **Willie** » Mon Apr 09, 2007 7:46 pm

That is not right! With plenty of oil on the shells t he crank should turn
quite easily. You could try tightening down only one big end at a time to
possibly trace the problem to only one of the bearings.

Post by **picky** » Mon Apr 09, 2007 8:01 pm

you probably have the main bearing cap on the wrong way round. try taking it off and turning it 180 degrees and tightening it up again.

Post by **wishbone** » Mon Apr 09, 2007 8:04 pm

Front bearing does up without tightening crank, Centre tightens somewhat but the worst is the rear. I havent tried in reverse order though!

Post by **wishbone** » Mon Apr 09, 2007 8:12 pm

Picky. I just checked but they only seem to go on one way round. The two small bolts on the rear and centre caps need to line up for the mesh filter, and they do!

Post by **picky** » Mon Apr 09, 2007 9:33 pm

ok, check that the bearing shells are inserted properly in both the block and the caps, there is a small locating "tang" that pokes out slightly, This must be lined up with the small cutout in the block and in the cap. if you take off the rear cap and look at it side on, does the bearing shell poke out slightly at one end? it should be flush with the level of the cap. check this on the block aswell. if you could post some close up photos of the block and the caps, that would help us determine your problem.

someone will realize what the matter is dont worry!!!

Picky

Post by **les** » Mon Apr 09, 2007 9:43 pm

They only fit one way, make sure that the shells are properly seated and the ends are flush with the block and cap faces. Worse case would be a crank that is not straight or the regrind is not accurate. If you have a micrometer, check the diameter, it should measure 1.7505 to 1.751 minus the 10 thou. I take it that the tightness is on the mains without the big ends attatched.

Post by **bmcecosse** » Tue Apr 10, 2007 7:35 am

Sounds like the crank grind is not correct. The crank should spin easily in the mains. Remove all caps and clean carefully behind the shells - then try assembling just the centre main - does it spin ok ? What about the thrust washers - are they causing the drag ? Try with and without. Then add the rear - how is it now? If it doesn't turn easily - take it straight back to whoever did the regrind.

Post by **wishbone** » Tue Apr 10, 2007 6:59 pm

OK I removed all the caps and thrust washers. Cleaned etc. Put the front one on and it spins ok. took that off and put the rear one on. tightened straight up, so did the centre one. i swapped the bearings from the front (which was ok) to the rear but it still went tight. Seems that BMC is right and the grind is bad! I don't have a micrometer so I'll ship back to esm I guess.

Post by **picky** » Tue Apr 10, 2007 7:27 pm

it is very unusual for this to happen, but looks like the only possilble explanation. make sure they give you new bearing shells, as they are now probably damaged.

Post by **bmcecosse** » Tue Apr 10, 2007 8:57 pm

Oh dear ! Picky is right - these shells will be ruined now. Either it's the grind - or the crank is bent, or your block is distorted which is highly unlikely if it was running before.

Post by **wishbone** » Wed Apr 11, 2007 7:49 am

Time to put my hands in the air and admit how foolish i've been! Turns out it was the rear BOTTOM cap. I hadn't even considered that it might be slightly out of alignment. i was taking the crank out to ship back when it struck me! I'm feeling stupid but glad I found out before making a fool of myself with the suppliers!

Oh and the crank now turns smooth and free. The bearings look ok but do you think they should still be replaced?

Post by **bmcecosse** » Wed Apr 11, 2007 10:13 am

Hmmm - but the rear cap should be sitting in dowel rings - it's not possible for it to be slightly out. Have the rings been lost ? The shells may be ok - depends how hard you have been 'forcing' it to turn. If they are just slightly scuffed then I guess I would use them.
Now - take great care with the pistons/big-ends. Do one at a time and check for easy rotation as you go.

Post by **wishbone** » Wed Apr 11, 2007 9:11 pm

When i say rear bottom cap, its for want of a better description! I mean the one that bolts to the rear of the engine with three smaller bolts. It does bother me though because I can't see how it doesn't leak oil!

Post by **chrisd87** » Wed Apr 11, 2007 9:31 pm

I think that might be the cap you're not supposed to remove as it's set up very accurately at the factory so it doesn't leak oil...

Post by **wishbone** » Wed Apr 11, 2007 9:37 pm

Ahh, it was removed by the engineers when they did the rebore. How do I set it up now?

Post by **chrisd87** » Wed Apr 11, 2007 10:01 pm

I'm having the one on my engine project set up by the engineers who are doing the rebore!

Post by **picky** » Wed Apr 11, 2007 10:25 pm

yes this part is crucial I bolted it back together when rebuilding my last 1098 and I must have done it much too loose I had loads of oil getting into the bellhousing. I think you can set it yourself, you slacken the three bolts, tighten up all the bearing caps and then using a feeler gauge it should be 15 thou from the crank... from memory but 15 thou sounds a bit too big in my opinion.

anyone else know the correct spacing??

Post by **bmcecosse** » Thu Apr 12, 2007 7:43 am

Just snug it up to the rear main bearing cap - and tighten the bolts. It's a scroll - 'designed' to work any escaping oil back into the engine. It must not touch the crank - but closer is better. It can only hope to work if there is little or no internal crankcase pressure - hence the reason good breathing is important on these engines.

Post by **Axolotl** » Thu Apr 12, 2007 8:55 am

The work shop manual says that the seal housing should be flush with the bottom face of the block, both laterally and vertically. It should have a paper gasket, which should be in perfect condition.

"After the set screws have been inserted to just more than finger tighteness, the housing may be tapped into its correct location and the screws finally tightened. Check the position again for flush fitting. [using a straight steel edge]"

The 15 thou mentioned in an earlier post referred to the radial clearance for the oil return thread in the crankshaft and the bearing, which should be between .0015" and 0.004" (0.038 to 0.101 mm). It suggestes using engineers blue to check the clearance.

Finally, to avoid leaks in that area, make sure the cork gasket protrudes 1/8" above the surface of the block, and that the sump gasket ends overlap the cork when refitting the sump. "emough to provide compression at these points, biut not so much the cork spreads out under the gasket when tightened". If necessary, shorten the cork gasket to achieve this. If it spreads out under the gasket when tightened, it will leak.