803 rebuild progress

[liammonty]

I can't give you measurements, but I know that the thrust washers on my 948 (which were supplied by the engineer when he did all the machining on the block and crank, so should have been the correct size) were exactly as you describe yours to be. Once assembled, end float was fine. I think yours will likely be fine also. There needs to be a little clearance.

[bmcecosse]

Make sure the thrusts are in right way round of course - bearing material to the crank faces - and 'steady' them with a wipe of grease while you do the assembly. Then check the end float. What does it measure?

[JOWETTJAVELIN]

Thrust washers were put in with the oil channels facing towards the crank as per the manual. End float taken at the centre main bearing is 6 thou.

So far:[frame][/frame][frame][/frame][frame][/frame][frame][/frame]

All I am waiting for now are the piston rings then I can have it done in a couple of days.

[bmcecosse]

These look quite reasonably sized big-ends - sure it's an 803 crank?? Hopefully just the picture angle making them look big. Your 6 thou is top end of acceptability - but it will be fine.

[JOWETTJAVELIN]

It's definitely an 803 crank, I mentioned to my engineer when he came to have a look that a weakness of this engine is the big ends, but he said, 'they are not tiny bearings!'

I suspect it is due to the oil pump letting them run dry at idle more than anything else - but that weakness is now solved.

[bmcecosse]

' my engineer ' oh dear...... And - you'll have to take all the set screws out again to fit the timing case cover.....

[liammonty]

It's the size of the bearings, and the material (at least of the originals) that causes them to fail so often. The crank is also prone to snapping- Vizard for one described it as a 'bent piece of solder'... That's why all later A-Series engines have sturdier cranks and bearings- they were identified as a weak spot. I think oil starvation is unlikely to be a problem at tickover- don't forget there ought to be some splash lubrication going on (unless the sump is empty!). My 803 had super oil pressure but still managed to destroy itself- not wanting to worry you ;) They just don't like hard work...

[bmcecosse]

There's no 'splash' - the crank doesn't dip in the oil.......

[les]

Seems to me that this 803cc engine hasn't got much going for it!

[bmcecosse]

Oh this is going to be the BEST 803 in the world ! Certainly the most discussed...........

[JOWETTJAVELIN]

' my engineer ' oh dear...... And - you'll have to take all the set screws out again to fit the timing case cover.....

The screws were left in so they didn't get lost. My man is a professional engine re-manufacturer and has been a great help - I don't know what's so 'oh dear' about that...

[bmcecosse]

Hah! Only because I (we?) thought you were doing all this yourself.............

[JOWETTJAVELIN]

Yeah, but I can't polish a crank myself and check the journals for size, nor de-glaze the bores. And quite frankly for what it all cost me (£20) I wouldn't want to.

I am building this up myself - using parts I have sourced - but I do not have a full-blown workshop!

[bmcecosse]

£20 is ok!

[les]

I wasn't singling out this particular engine but all 803s!

[JOWETTJAVELIN]

I can't give you measurements, but I know that the thrust washers on my 948 (which were supplied by the engineer when he did all the machining on the block and crank, so should have been the correct size) were exactly as you describe yours to be. Once assembled, end float was fine. I think yours will likely be fine also. There needs to be a little clearance.

Thanks for the reassurance - I was concerned that these could be wiggled about easily!

[JOWETTJAVELIN]

Recently the piston rings arrived so after the pistons have been scrubbed in petrol they will be going in.
Rear main bearing cap was given a light coating of Hylomar to ensure an oil-tight seal. Use sparingly so as not to get any on the bearing surfaces!
[frame][/frame]

Then the end-cap was replaced, using the locating holes and lightly tightened down, each bolt a few flats at a time to ensure even contact.[frame][/frame]

Here we can see the blue doing its work:[frame][/frame]

All that was left to do was torque all the end caps down to the specified figure. The torque wrench was from Lidl and is excellent quality.[frame][/frame]

[bmcecosse]

Noooooooo! You should NOT have put any hylomar (or anything else) on the faces of the bearing caps........ No matter how thinly - it will be holding the cap off the surface ever so slightly. I doubt it will matter - but you should not have done that. Perfectly clean metal to metal is what was required. Hopefully - the crank still spins round easily? You should test it as you tighten each main bearing - and of course after each big-end when you get there. Great picture BTW!!

[JOWETTJAVELIN]

Thanks. But I was only following the manual sir! (BL Workshop, not Haynes) which states use Hylomar on rear end-cap. I can understand this, to prevent oil getting to the clutch.

The crank spins like a dream and each end cap, starting from the centre, was torqued down to 9 kg/m.

We shall see what happens...

[stevey]

Great progress!!!! Keep the snaps coming, will be doing mine soon, so much better that squinting at the manual snaps