A good idea?

[JOWETTJAVELIN]

I have two 803 engines, one slowly being rebuilt and the other in the car slowly dying (you may remember this could have been due to me not priming the oil pump).

So the one I have in the car is knocking at start-up and speeds over 25MPH and, whilst running with good oil pressure is clearly not fit for use.

Today, after dismantling the dead 803 (see relevant topic), I had an idea, see what you think:

There are a set of 3 good big-end shells from the dead engine. I am thinking of dropping the sump on the engine in the car, finding which bearing is at fault there and replacing the shells with those salvaged from the dead 803. Hopefully the crank will still be in good enough condition to keep it going OK for a while.

A bit unorthodox I know but I've nothing to lose by doing it. What do you think?

[mike.perry]

Do the job properly and fit a new set of the correct size shells. Do you know what size regrind the cranks are? Have you checked the mains?

[JOWETTJAVELIN]

That would mean taking out the engine again when I already have one I'm rebuilding - no point. I'm pretty sure it's all standard, obviously if it's oversize my idea won't work.

On the dead engine I am doing a proper job with new crank and bearings etc.

[mike.perry]

You need to remove the main bearing caps to check that they have not picked up any swarf.

[linearaudio]

Getting past the niceties of proper engineering-GO FOR IT!!!As you rightly say, you have nothing to lose, and when things are at that point, the true bodger(not a derisory term, that would be a BOTCHER!) would do just as you suggest. Stick it together with silicone sealer to avoid unneccessary new gaskets, and be happy until you sort the final job out!
NB: Look up various definitions of "bodger". Can't remember which philosophically written mechanical work I read it in, years ago, that a Bodger uses sensible, if maybe unorthodox, methods to acheive a result.... A Botcher uses Gaffer tape and tie-wraps!
Bodgers also mess around with timber seat framing, on another plane(wood plane maybe)

[drivewasher]

As one member would say "Oh Dear"
Concentrate on one engine at a time, finish the one you have out properly then put it back in a car knowing it's a gud un. Then strip the other one and inspect at your lesuire.
As for silicone use it as a last resort when the right gasket cannot be obtained.

[linearaudio]

Sorry, I obviously misread the thread(s)! I had the impression that the OP wanted a "quickfix" to keep him mobile until the decent engine was done. Very sorry if I misread the situation! The point I was getting at was that if you have a running car, and a project engine in the offing, which happens to be just what my situation is, then to drop the sump, fettle what you have a bit, then seal it up, all quick and cheap, to keep you going, is what I would advocate, but.... NOT AS A PROPER FIX!!!

[JOWETTJAVELIN]

You got it right linear All I want is a quick fix to keep me mobile as this is my only car!!!!

We are doing a proper job of rebuilding the original engine, but the one we have put in is now grumbling and is not fit to be driven very far.

I cannot be waiting weeks whilst it is off the road til we finish the other engine.

My idea is as OP, replace the defective big-ends in the running engine with good ones salvaged from the other engine, by simply dropping the sump and doing it. I have nothing to lose by doing it.

Thanks so far for the comments - seems to be a 50/50 as to whether it's good or bad but I like linear's answer.

[drivewasher]

I did miss read the OP as I thought his running car was running ok at the mo. but deteriorating slowly!

Turns out Mrs Dw is right then, Iv'e got a manual brain and an automatic mouth!

[linearaudio]

Thank God for that!! I thought my mind had wandered away then! YES To drop the sump, put some "better" bigends in, and wodge it up with silicon will get you going! IT IS A DEFINITE BODGE, but it will cost you 2 hours and nothing much else, so do it!!
As a complete bodge aside, my brother was sold a lame VW Jetta (1.6 diesel Polo with a boot) years back in the days when VW hadn't sorted out brake caliper and linkage bending problems .This thing was a pig to start, had an awful top end rattle and overheated, along with low oil pressure. Measuring the (overhead) cam cap bores, they were round, but 0.7mm larger than the cam journals. As a nothing-to-lose exercise, we "linished" 0.55mm off the bearing caps to bring the vertical clearance within tolerance(ughh), then individually selected and linished the cam shims to set the valve clearances. Result- a totally reliable rattle free engine with good oil pressure, for no cost other than a bit of judicious "linishing"- OK,really running the parts on the side of an offhand grinder wheel (shock-horror/ shattered wheels, deadly danger, etc!) The sod still overheated, this turned out to be due to a plastic flow seperator in the radiator disintegrating. A sheet Ally seperator, pop-rivetted and re-crimped into the ally side piece with... silicon sealer!!!!... set the whole thing right. Most would have had the car crushed at a great loss and moved on.....

[JOWETTJAVELIN]

Love it! Yes you can't beat ingenuity like that. It's only what owners would have done back in the day anyway. I read a tale of a guy in the 1950s with an old Austin 10 (an old banger then), he had to shovel Fuller's earth into the clutch inspection cover to soak up the oil leaks which caused the clutch to slip.

[bmcecosse]

I agree - go for the shells job - well worth a try. BUT - word of caution - this can only hope to work if the shells are same size - not +10/20/30/40 thou on one engine and STD on the other. Any oversize would be shown as a light stamping on the back of the shells - so compare closely before fitting. Only do one bearing at a time - and make sure the engine still turns easily after doing each bearing before moving on to tackle another. I appreciate that it may just be one bearing that's rattling, But well worth a try - nothing really to lose as you say!

[JOWETTJAVELIN]

Well I'm due some good luck but I'm pretty sure they will be STD. The salvaged ones are not marked as oversize.

Fingers crossed and I'll let you know how I get on.

[JOWETTJAVELIN]

Unfortunately the plan didn't work as the shells I was going to use were +.060 and the ones to be replaced STD. Had it been the other way round I would have just packed the bearings with steel shimstock.

I only realised what the markings meant after we couldn't get them to fit: I060 u/s was actually .060 undersize (crank)!

New STD bearing set ordered (£60). Shame about them being too big otherwise the plan would've worked.

Mike, we checked for swarf but fortunately there was absolutely no trace of it.

The crank looks OK, having ran a fingernail over it I couldn't feel any grooves/ridges.

This begs the question, do you think the +.060 crank from the duff engine will be accepted for the service exchange scheme? I'm no expert but it looks in a bad way and is already well undersize.

[bmcecosse]

Bad luck - it was a good plan.... and that's some price for shells - I wouldn't bother!! Just get an exchange crank. It's hardly any more..... You can try the exchange route - but frankly the crank is scrap because there will be no +80 shells.......But will they realise that? I once swapped a broken crank to BMC - made sure it was nice and greasy/dirty - wrapped in plenty of newspaper and when they handed me the 'new' exchange crank, we pulled it out the box and stuffed the broken crank into the box and handed it back to the parts guy. He took it, turned round , walked over to the wall behind him and just dropped it to the floor! So if it was later found to be broken - hardly my fault!! We ran for it..... Another time I managed to get hold of an 803 crank for nothing - and swapped it to them for a nice reground 948 crank..... It seemed a better way than trying to swap away the broken crank again......

[les]

Just read your post about packing the bearings if the other way round-- you couldn't do that as the diameter is constant and the shells don't bend.

[bmcecosse]

Aye - I just ignored that bit........

[welshrat]

Bad luck - it was a good plan.... and that's some price for shells - I wouldn't bother!! Just get an exchange crank. It's hardly any more..... You can try the exchange route - but frankly the crank is scrap because there will be no +80 shells.......But will they realise that? I once swapped a broken crank to BMC - made sure it was nice and greasy/dirty - wrapped in plenty of newspaper and when they handed me the 'new' exchange crank, we pulled it out the box and stuffed the broken crank into the box and handed it back to the parts guy. He took it, turned round , walked over to the wall behind him and just dropped it to the floor! So if it was later found to be broken - hardly my fault!! We ran for it..... Another time I managed to get hold of an 803 crank for nothing - and swapped it to them for a nice reground 948 crank..... It seemed a better way than trying to swap away the broken crank again......

Careful BMC your 'role model' status may be reduced following this thread, think of the young uns! However guess we have all chanced our arm and got an unexpected good result, full marks I say.

[JOWETTJAVELIN]

To update on this recurring problem, I have had the sump off 3 times swapping bearings and have come up with a temporary solution (can't take engine out to remove crank for regrind/swap for other reasons).

A lot of you will frown on this but it's not worth spending the money on:

I filed the end caps down slightly and lightly hammered the bearings with a rubber mallet so they would fit the crank snugly. Then on each bearing end cap I inserted two pieces of steel shim, then tightened them back up.

It is grossly un-proffesional but the knocking isn't as bad, plus it's still running with very good oil pressure.

At least I can coax a few more miles out of the old tub...

[MarkyB]

A common bodge back in the day.
Next stop putting sawdust in the noisy back axle!