gearbox leak

[cadetchris]

having just rebuilt the bottom end of primrose's engine, i have discovered a leak from the rear of the gearbox, where the prop shaft slots on to. is this easy to fix? and it be fixed with the gearbox still in the car or do i have to yet again (would be for the 5th time this year) take out the box and rebuilt it on the bench?

answers to the usual address please

[PSL184]

It can be done in the car. The biggest problem is that the new tail seal needs to be reamed to the diameter of the propshaft.

[bmcecosse]

Have you sorted the 'tight' engine ??? If the gearbox leak is not too serious - leave it be! The seal can be changed easily enough - but if a new rear bearing is required that would be a bench job - and as already mentioned - it needs reaming to size...........

[cadetchris]

the tight engine was solved, the bearing cap on number one cylinder for some reason wasnt quite right, so i swapped it for a spare one i had and it turns beautifully now. it has a rattle, which i cannot figure out as everything is tight and torqued down to what it says in the book, its coming from the front end, but i cannot figure out what it is.

as for the gearbox. its not a huge leak, just annoying, so ill see how it goes for a couple weeks and the see what its like

[bmcecosse]

You can't just swap bearing caps around like that!!!!!!!!!!!!!!!!! The cap is machined carefully with the matching con-rod. Unless you changed the complete con-rod ? You will ruin that new crank.

[cadetchris]

fudge, could that explain the rattle then?

so, bearing in mind that with this other bearing cap on, the engine dosent turn, what could be the problem?

[bmcecosse]

Well - if it has somehow been damaged - best solution will be to change the complete conrod. ie Rod + matching cap!

[cadetchris]

and that presumably means head and sump off to whip out piston.

[bmcecosse]

Fraid so.........

[cadetchris]

ah,
could it be that i simply swapped some of the caps over by accident when i was rebuilding? when i took them all off i lined them all up and i might of reassembled them starting from the wrong end, which would mean a swap with another bearing cap already in the engine would solve this problem. or it could mean that all of them are on the wrong conrod, which i presume presents a bigger problem

[RobMoore]

Looks like a game of eeny meeny minor mo for you

[cadetchris]

it does, not one i am particularly looking forward to. it would of been nice if the caps and rods had been marked by the factory, but alas not

[linearaudio]

it does, not one i am particularly looking forward to. it would of been nice if the caps and rods had been marked by the factory, but alas not

Are you taking offers for the car as a non-runner yet

First rule of stripping an engine is to mark 1,2,3,4 on the relevant conrod and cap, but of course, you won't EVER forget that again will you!

If you are now doubting all your caps, then remove all the rods, take the shells out, KEEP A NOTE OF WHICH SHELLS WERE WITH WHICH ROD, bolt the caps back on( no need to torque them, just nip up), and feel for a ridge between the two mating halves. There shouldn't be one, the surface should be continuous across the joint. If there is a step (it will only be small) then I guess it's as stated previously-eeny,meeny.....There's not too many permutations though

[bmcecosse]

Dear God - I sincere hope you haven't mixed up the caps - and then RUN the engine ?? You must do as LA directs - and get them all sorted out so they match up perfectly. It's not too hard to do - I had to do it with a set of 'S' rods - but do take your time and get it right. And then - rods and caps with dots with a centre punch. Just mark 1, 2, 3 - obviously the other one is 4![frame][/frame]

As well as marking them - I tied them in pairs with tie-wraps so i don't need to do that again........

The sharp eyed amongst you will have noticed that the gudgeon pin holes are right at the top of these rods. That's because these are the v rare 970 S rods - slightly longer than other S and A series rods - yet same forgings, same part numbers!

[cadetchris]

luckily, very luckily, i havent started primrose yet, been busy with other bits.
so i am going to fettle with the engine again tomorrow. on a slightly related note, i did mention my cap problem to a machic friend of mine, he did say that it didnt really matter as the bearings would bed in after a couple of dozen miles.

this was taken with a pinch/bucket of salt

[bmcecosse]

Earlier on - you said there was a rattle! Your pal is mad. Don't let him anywhere near your car........

[cadetchris]

yes, the rattle was noticed when i turned it over by the handle, so i stopped at that and went for dinner. hopfully not much disturbed doing that

[bmcecosse]

Oh dear - sump and head off for full inspection! There must be NO rattles! Try it on the handle once you have fixed the problem - BEFORE you refit sump and head.

[cadetchris]

ah, well ill order the bits this evening and wait for the weekend

[bmcecosse]

You won't need any 'bits' surely ??