Crank has tight spots

[MsRose]

Hi all

Some of you may know I'm restoring a 1957 which has a 948 engine in. The engine was seized solid and so the block, head and crank went to an engineer. The crank was re ground (had been done once before).

I'm not a mechanic, but did have an experienced person watching over me when the crank went it.

My problem is this, the crank requires a fair bit of force to turn, but also has a tight spot. The crank was taken back out and I could clearly see some marking on one of the bearings. The main bearing cap was checked and there was a very slight raised surface, looked like it had taken an impact at some stage. This was smoothed down, cleaned and oil applied before re seating. I checked the other two and found no raised spots, but still re cleaned and oiled. This did make the rotation slight better, but absolutely clear that there were still tight spots.

The mechanic watching over me said he wasn't happy and so I called the engineer, who has kindly said he will come and take a look, but this won't be until next week sometime and curiosity is getting the better of me, so thought I'd come on here and see what you lovely people in my phone think? I'd be very grateful of any advise and comments, and will of course update once the engineer has visited.

[philthehill]

You are correct to be concerned. The crankshaft should be easy to turn without effort when installed but not connected to the conrods or timing chain.
Do you have the right thrust washers? There should be 0.003" to 0.004" for and aft movement of the crankshaft when installed.
Is there any sign that the main bearing caps have been filed on the faces that contact the block?
That caught me out once with a Standard 8 engine evil:
Make sure that the centre main is the right way round (I doubt that it is the wrong way round but better to check).
Have you been supplied with the correct size crankshaft bearings. The bearings are marked with the undersize i.e. 0.020" on the back of the bearing.
The engineer should be able to state the undersize regrind which should correspond with the sizes on the back of the bearings. The crankshaft needs to be measured with a micrometre to be determine the regrind size.
Please keep us posted on what the engineer finds/states correct or otherwise.
Good luck
Phil

[philthehill]

Was duplicate post now deleted.

[MsRose]

You are correct to be concerned. The crankshaft should be easy to turn without effort when installed but not connected to the conrods or timing chain.
Do you have the right thrust washers? There should be 0.003" to 0.004" for and aft movement of the crankshaft when installed.
Is there any sign that the main bearing caps have been filed on the faces that contact the block?
That caught me out once with a Standard 8 engine evil:
Make sure that the centre main is the right way round (I doubt that it is the wrong way round but better to check).
Have you been supplied with the correct size crankshaft bearings. The bearings are marked with the undersize i.e. 0.020" on the back of the bearing.
The engineer should be able to state the undersize regrind which should correspond with the sizes on the back of the bearings. The crankshaft needs to be measured with a micrometre to be determine the regrind size.
Please keep us posted on what the engineer finds/states correct or otherwise.
Good luck
Phil

Thanks for coming back to me. The thrust washers are standard size. The crank float was checked with the original ones (standard) and there was no movement. It was someone experienced that checked this as I didn't want to get it wrong.

The engineer called me and gave me a list of all the bearings to order and the sizes, so hoping that should all be correct. The faces that make contact with the block all appeared to be smooth. The center bearing was put on with the hole for the oil strainer on the camshaft side. Is that correct?

[philthehill]

Re oil strainer mount bolt hole - that is correct, camshaft side.

[MsRose]

Ok, got to the bottom of it and lesson learnt!

The long and short of it was a piece of debris, which was tiny, sat underneath one of the main bearings. I've been shown how to clean everything up, but the engineer carried out a quick clean up to prove the crankshaft and, hey presto, spinning as free as a bird.

Needless to say, I'm cheesed off with myself, but at least the cost is only another set of bearings and a bit of fuel to run everything over to the engineer.

I'm trying to fix posting pictures on here, but if you want a peek at what I'm up to, you can find it here https://www.facebook.com/groups/1309792820116561

[svenedin]

Well done and that’s great news. I am doing some major restoration work on my car at the moment. No day at all goes right the whole time. There are always challenges and sometimes a sinking feeling of 2 steps forward and 1 step back. Everything takes so much longer than I think it should. Chin up and keep going!

Stephen