big end noise

[Onne]

It is indeed not an engine rumble, but a gearbox one. Time to check the oil I think. If there is any left at all in the box

Onne

[bigginger]

Phew! A *VERY* quick look at that engine today, all I noticed was that the rear cap appears to extend all the way through the plate. Another look tomorrow, if time - that was about 2 seconds worth

[Scott]

This may be me being thick. But if you cant get pistons out of top of engine on a sidevalve, how on earth are you going to get them out of bottom with crank insitu. If you did manage to get them out, you know what my next question is gonna be, how do you put them back. I find it difficult putting pistons back in from top , the ring compressor usually moves just as I get to top ring.
Ian.

Warning - off topic hijack, sorry Andrew .
The sidevalve pistons indeed come out through the bottom of the block.

There's a chamfer at the bottom of the bore to refit them with the rings in place - in theory.
In practice, I fit the pistons without the rings. Push the piston all the way to the top & out as fas as possible. Then fit the rings & use a ring compressor in the usual fashion.
P.O.P.

[Onne]

even the bottom one?

[Scott]

even the bottom one?

I'm sure I didn't fit any rings before fitting the piston from the bottom. It's been quite a few years though .
Have a quick look - it won't take long to see if you can or not .

[Onne]

well, my block is 4 miles away, still at the workshop, but I will

[chickenjohn]

If its only rattling when idling, then surely its just the timing chain???

[Cam]

Scott that makes perfect sense thanks. I measured the rods & pistons and the rod ends are around 69mm wide and the bore is 57mm so there's no chance of it fitting through like the A-series.

[bigginger]

Warning - off topic hijack, sorry Andrew .

S'OK - I'm the world's biggest fan of off topicness (see posts passim) That's a poor attempt at going off topic though...

[Onne]

and I will allow it, of course, being a great fan of going off topic

John, my ears aren't that weird, the noise comes from behind the engine ( say at bulkhead ->gearbox!) level.

And I haven't checked my gearbox oil for 4000 miles or so. shame on me!

[brixtonmorris]

I feel like there is only one remedy; the bigends!
a gallon on 550 miles is just too much! (its 20W50 Valvoline, SL rated £9 per 5 liters)
Onne

the rate of oil loss is due to it being spat out of the rear main bearing and onto the road. higher the revs the more oil out the back.
the oil from the front main drips into the timming chain cover, and the center one into the sump. The front and rear also lose oil into the sump.

if you replace the big end bearings only, what you will do is raise the oil pressure in the crank, therefore forcing more oil out the rear main, adding to your oil loss. this will also mean that the new big ends will not be lubricated fully, espically if the crank is in good shape.
if you want to stop the oil loss you will need to have the mains reground and new bearings fitted. this still will not completly stop oil dripping out the rear, its just the way it is.

[Onne]

I will check my sump gasket though. Even the simple things can go wrong.

Thank you very much for the info

[brixtonmorris]

check the split pin that hangs out the bottom of the gear box casing.
oil leaks from the rear mains tend to find it way out via that little hole.

[Onne]

Why is there a split pin there anyway? Of of many Minor Mysteries. To m anyway

[Welung666]

It's there to add another rattle

[Onne]

So that is why they leak oil! To stop the rattle! Makes perfect sense

[bigginger]

Why is there a split pin there anyway? Of of many Minor Mysteries. To m anyway

To all of us! I asked the same question, then deleted it 'cos I thought it would just be ME being dim. Anyone know?

[Onne]

We'd better make a Do You Know out of this one.

My sidevalve also has one

[Cam]

It's a crude method of stopping large bits finding their way from the road into the bell-housing while leaving the hole open to let the oil out. Seems to work OK. I had to drill a hole in the Ford bell-housing and fit a split-pin for the same reason.

[ian-s]

I thought it was so the oil leaking from the rear main couldn't mix with dust off the clutch and form a gungy paste to block the hole totally.