big end noise

Post by **Onne** » Sat May 06, 2006 10:43 am

When is the noise the most obvious? My car tends to make a bit more now when it idles, and it comes from the bottom end of the engine. I feel like there is only one remedy; the bigends!

And would it be possible to do the pistons rings with the engine in the car?
Because they tend to use up a bit of oil.

a gallon on 550 miles is just too much! (its 20W50 Valvoline, SL rated £9 per 5 liters)

Onne

Post by **bigginger** » Sat May 06, 2006 11:13 am

You can do the rings and big ends with the engine in the car. You'll need to take the head off though (duh) to do the rings, and drop the sump to get at the big ends, then spend a fair bit of time on your back with oil dripping into your eyes. Get yourself a ring compressor too - and if you're getting the new rings sent, I'd get two sets in - if you're as cack handed as me, you'll break a ring

Don't forget a new head and sump gaskets while you're ordering. And a torque wrench, preferably one with a Lbs/ft scale. Be wary of using the car till it's done - if you score the crank, it'll need to be reground.

Post by **Onne** » Sat May 06, 2006 11:22 am

What exactly do you mean when talking about not using my car? As from now on? And I don't even know if there are oversize pistons in there.

So if I remove the bigends from the crank, taking great car not to score anything, can I draw out the piston including pushrod from above? Because you can't on the sidevalve.

Would it be wise to get a new oilpump?

Post by **bigginger** » Sat May 06, 2006 12:15 pm

It's the bearing shells breaking up and scoring the crank while you're using it that's the danger. Yes, you have to push the piston out from below once you've undone the big ends, then it's pretty easy - you may need to push it out with a length of (clean) wood/hammer handle/whatever. New oil pump is a good idea as well - not done one yet though, does it HAVE to be at the same time? I think you can leave it if you don't want to do everything at once.

Post by **Packedup** » Sat May 06, 2006 2:29 pm

Onne wrote: So if I remove the bigends from the crank, taking great car not to score anything, can I draw out the piston including pushrod from above? Because you can't on the sidevalve.

I thik BigG has far mpore experience of this than me, but basically yes. You drop the bearing cap, pull the head and shove the piston/ rod assembly up till it makes a break for freedom. Then fit new rings and drop new big end shells on when refitting the rods.

If you're doing the big ends, it's false economy not to do the mains at the same time, and use the best quality bearings you can afford. Even then, if there's significant crank journal wear it's only a temporary fix (though in my opinion you can get away wth very lght wear).

Would it be wise to get a new oilpump?

Probably, but then you've got to pull the engine or the box to get at it - So it depends just how much you want to take apart!

Post by **Cam** » Sat May 06, 2006 3:20 pm

Onne wrote:Because you can't on the sidevalve.

Are you sure? Not tried it myself, but how do you do it on a sidevalve then?

Post by **Onne** » Sat May 06, 2006 3:43 pm

take out the pistons Cam? From below, so the head wouldn't need to come off. This is because the bigends are too large.

Packedup, I know I shoudl chaneg the main bearings, but that would mean getting the crank out (thus the engine)

In the mean time my neighbour(who has had numerous old (knackered) cars) has heard the noise, and he thinks it's play in the box.
The engine does turn over very nice and smooth

Thanks for all the advice!

Onne

Post by **bigginger** » Sat May 06, 2006 4:21 pm

AFAIR, some people (person?) reckoned it could be done in situ - not sure I understood quite how, but try a search on here. I think it was one of my posts on the same sort of topic.

Post by **wanderinstar** » Sat May 06, 2006 5:03 pm

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.

Post by **bmcecosse** » Sat May 06, 2006 5:09 pm

To test for big-ends - get an oil pressure gauge. Big ends rattle most when decelerating - mains 'rumble' under load. You can change mains in situ - need to get the timing chain and gears off though. Oil pump is engine out job.

Post by **Cam** » Sat May 06, 2006 5:50 pm

wanderinstar wrote: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.

Exactly what I want to know too!

Post by **wanderinstar** » Sat May 06, 2006 5:52 pm

Hi Cam,
Its not me then.
Ian.

Post by **Packedup** » Sat May 06, 2006 8:35 pm

Onne wrote: Packedup, I know I shoudl chaneg the main bearings, but that would mean getting the crank out (thus the engine)

It wouldn't - But it would require a strange form of masochism and a whole new load of swearwords if it's anything like the job on the cars (obligatory not a Minor disclaimer/ note) I've got/ done it on!

A little bit of time and less than precision engineering will see the top halves of teh bearing shells come out, and refitting is the reverse. I can't actually remember the inside of the inline A bottom end, but I'm pretty sure you can get to all three main bearing caps with minimal difficulty. You then slacken all three which allows the crank to drop the minute amount required to remove and replace the shells

May as well do the thrusts at the same time, for no other reason I suppose than you're there and it's one less potential job in the future.
I'm sure someone on here actually has done it, rather than theorised!

As for actually diagnosing bearing wear - Lack of oil pressure when hot, slow build up of pressure when starting, knocking/ rumbling/ clacking under load (rumble at higher revs, knocking usually under load in lower gears) are the symptoms I'm most used to. A oil pressure guage is either an excellent addition or a paranoics nightmare depending on your point of view, but it would certainly give you some insight. But new shells will only help keep the oil where it should be, they won't really compensate adequately for a worn pump, in my opinion. So given how comparitively easy it is to pull a Minor lump, it could be worth considering going the whole hog with the oily stuff

Post by **Onne** » Sat May 06, 2006 8:54 pm

I thinjk we might be confusing two engines here! I am talking about my 1098.
And you lot say I can take the pistons out from the top. That was partly my question, since I have no experience with the 1098 yet.

When I dismantled my sidevalve, I tried to remove them like aforementioned, but didn't succeed, since the bigends were about 1/2" larger than the bore. So they came out from the bottom end, with the crank removed.

But if Roy is right, then I don't have to worry about my bigends, because there is NO rattle at all at decceleration, only when idling.

Lastly, I think the best option is to completely remove engine and box, and do it on the bench. All the bolts on the front grille assembly are quite new, so the should come off easily.

Onne

Post by **picky** » Sat May 06, 2006 9:47 pm

I tried to remove all three main bearings caps on a 1098 as packedup suggested, but only the middle bearing cap seemed to budge, and looking at an exploded diagram in the haynes manual shows that the front and rear engine plates would have to come out to let the front and rear bearing caps come out, so in my opinion, im not sure the main bearings can be replaced without removing the engine.

Post by **bigginger** » Sat May 06, 2006 9:52 pm

That's what I thought, certainly.

Post by **Onne** » Sat May 06, 2006 9:53 pm

I'll go with that too, front end has the timing chain, rear has clutchy things

Post by **Packedup** » Sun May 07, 2006 12:03 am

But the timing chain and clutchy bits are on the nose and tail - outside of the bearing journal areas. It's been too long since I actually had the sump off an A for me to remember what it looks like in there, but I'm suprised there's no chance of getting the caps off without removing front and rear plates. I'd be less surprised if there were smaller bolts running through other bits into the bearing caps though come to think of it (most likely timing chain cover/ area?)

Unfortunately (or fortunately? Depends on your point of view!) I've not had anything like the number of A series apart that others around here have, so anything I say is possibly wrong due to hazey memory and lack of experience when it comes to the finer points of bodger... erm, "shortcutting"

Post by **bigginger** » Sun May 07, 2006 1:18 am

I'll have a good nose around tomorrow, if I get time - I've got a block I need to strip and return to ESM to get my deposit on the new one back, but lots of other Minory things to do too

Post by **bmcecosse** » Sun May 07, 2006 4:14 pm

Hmm - you've got me wondering now - I thought the rear cap could be fiddled out with the backplate on - maybe not. Certainly to get the front one off you need to remove the two little screws going in through the front plate - so the timing gears need to come off. The actual front plate can stay in place - may need to fiddle up the gasket slightly !