Installing Main Bearings

[SteveW]

My block is now back from the machine shop. I got them to crack test the crank and thankfully it was fine, but it needed a regrind from +30 to +40. I've started the rebuild and the centre shell fits perfectly, but when I put the end ones up against the originals, you can see that they have a slightly larger (maybe around 1mm) outside diameter than the originals. I guess that I could tap these into the caps and block, but I just wanted to check that I should do so as they will obviously distort by that much. Either they are made so that they are perfectly round once they have distorted by tapping them in, or the outside diameter is an error. Which is it?

[Gene Gillam]

Steve, they’re normally a thumb press tight fit in the cap...they should be fine but if not, they’re easy to remove without damaging them.

[Steve Simmons]

I would press them in by hand, or possibly with a piece of wood and see how it goes. If they still sit proud then there is an issue, but I but they will fit once fully seated.

[SteveW]

They just required a bit more pressure on them than I originally felt comfortable with to make them fit. They are all now in, I've test torqued everything up and the crank turns without locking up. The end float is right on the lower end of the range, which is as it should be for a reground crank with new bearings.

Next job is to fit the con rods to the new pistons, insert them through the block, fit the rings and then bolt up the big ends. Obviously I have to take the crank back off to do it.

[EdCallo]

You may be in for a surprise. The big end of the rods will not fit down the piston bore. I push the pistons through without the rings on from the bottom side. Install the crank. Put the rings on the piston and push down to connect to the crank.

Others have worked pistons past the crank from the bottom but seem to much of a chance to damage something that way.

Oh, the flywheel may need to be bolted to the crank before you install the crank.

Can't be built like a SBC

Ed

[SteveW]

No surprise. This is just a test fit to make sure that the crank doesn't lock up with the caps on. It takes 5 minutes to take it off again.

I though that it is possible to put the flywheel on with the crank in place, so I'll try before I take it off again.

[timandgerda]

Hi Steve,

Are you going for the new type crank seal with the sleeve? If so if have a tool that locates the carrier centrally that you are welcome to use. You have the have the crank and shells removed as it fits directly into the block and a little bit of machining is required on the new seal carrier but it eliminates any issue with previous owners skimming the main bearing caps etc.
Cheers
Tim
P.S. Away at present with work but home this weekend if you need it.

[SteveW]

Hi Tim,

My plan is to stick with the stock arrangement for the rear oil seal but to put a viton seal on the front end. However, if you have a clutch centering tool then that would be useful. By the way, I've just sent you an e-mail with a picture of my flywheel and a question that I hope that you can help with.
Steve

[JohnW]

My block is now back from the machine shop. I got them to crack test the crank and thankfully it was fine, but it needed a regrind from +30 to +40. I've started the rebuild and the centre shell fits perfectly, but when I put the end ones up against the originals, you can see that they have a slightly larger (maybe around 1mm) outside diameter than the originals. I guess that I could tap these into the caps and block, but I just wanted to check that I should do so as they will obviously distort by that much. Either they are made so that they are perfectly round once they have distorted by tapping them in, or the outside diameter is an error. Which is it?

When I worked at Vandervell Products the difference you describe was known as free spread. Free spread tends to disapear on high milage and over revved engines. Over revving can cause excessive vibration (unless it has been dynamically balanced) which is what removes the free spread.

[frenchblatter]

I've always been able to fit the flywheel with the crank in (but sump off).

I have a clutch spigot shaft, I'll bring it with me when you're ready.