15 replies to this topic

[cobblers]

After faffing about kidding myself that the noise wasn't the bottom end, I gave in to the inevitable and stripped the engine to find the no.4 piston big end had spun, making a fair mess of the crank. The rest of the bearings on the crank are also quite scored (it seems there has been a lot of metal floating about in the oil system)

The engine was rebuilt approx 3k miles ago for the previous owner of the car by a company in hull (don't know the name) to a 1330cc with some headwork, a cam, lightened flywheel etc.
The pistons/block are all in very good condition - neat honing marks still visible etc. it's a 1988 stamped 1275 block.

I can't seem to find a lot of info on what's what with regards regrinding the crank. It's probably already been ground with oversize bearings fitted.

The big ends measure:
1:44.45mm No scoring
2:44.45mm No scoring
3:44.44mm Light scoring
4:44.20mm Bloody awful mess, slightly oval (44.2 is smallest diameter) and a few small darkened areas

and the mains measure
Timing chain: 51.75mm light band of marking around centre where oil feed is
Middle: 51.75mm light band of pitting in centre
Flywheel: 51.85mm, very heavy pitting around centre

With all that, I've got a few questions:

Is there scope to grind the crank further and fit oversize bearings? If not

Since the rings and pistons and bore are so new, can I reuse my existing piston rings? I've left 1,2 and 3 in the bores, but removed no.4 because the rod end is very scored on the inside where the bearing span. I'd like to replace all the rods ideally, for peace of mind!


Heres a little video illustrating how much play it had:
_Y3NyiT5sfY
And the noise it made:
flsR6st1j_s

I'd be grateful for any other advice you can give me with this - It's the first time I've had an engine apart that I wanted to go back in a car!

[Surfbluegarage]

i think the minmum you can go down to on a a+ is 43.44mm on bigs and you have very big main journels at 51mm so you have plenty left for a grind on those too.check the bearings that were in them on the back. if they say STD there standard or theyl say +0.... something.
as regards to the rods.. was there any reason you put innocenty or a series 1300 rods in? were they just of convinience or did you specifically want those? id just get a set of a+ rods or if you want to spend some mullah the a nice set of arrow rods will do just fine hahaha

[cobblers]

43.4mm, nice one Plenty to go at then. I forgot to bring a "good" bearing with me (the engine is at my garage about a mile away) so can't check them.
Yeah, I've just read something that said these are early rods. No idea why they were used (Bought the car off here 2 months ago running fine, by the time I got it 100 miles home it was knocking like mad ) but from the looks of things, proper a+ rods are probably lighter (without the big weights on either end)
Are there any real benefits from using a+ rods over early ones?

[Surfbluegarage]

no not really there both just as good just those a series caps have extra weight on them but does balance out with the piston somewhat better. i prefer a+ but its personal preference. mainly only using a series rods in a a+ block is matching it to the crank and pistons as some a series journels are smaller in diameter like S rods have smaller little ends but its up to you.

Edited by mini_mad_daps, 24 October 2009 - 02:29 PM.

[cobblers]

no not really there both just as good just those a series caps have extra weight on them but does balance out with the piston somewhat better. i prefer a+ but its personal preference. mainly only using a series rods in a a+ block is matching it to the crank and pistons as some a series journels are smaller in diameter like S rods have smaller little ends but its up to you.

Cheers.
What's the best way to check if I have an A or A+ block? I'm basing the 1988 figure on the date stamping in the gearbox drive casting on the end (the only date I noticed)
I'm assuming I'm best off checking that it's an a+?

been quoted £100 my a local firm for a regrind to +30thou on my crank, including bearings to match, does this seem reasonable?

Any tips for cleaning the oilways out? I plan to just blast them out with a compressor once or twice and perhaps fine some petrol or paraffin through to flush them out. There is copper everywhere (got bits of it on my hands now after handling the crank, which I've already cleaned once!)

Same goes for the gearbox - how can I clean this out?

[MRA]

That is an "A" series block as the alternator bracket is of the long type (for dynamo) ....

It's the big end that is different at 1.625" as opposed to 1.75" in diameter, the little ends are the same.

Remove ALL of the oil gallery bungs and get some very thin long pipe brushes, once you have got them clean.... then clean them again, from experience I have found that there are a lot of engine builders who do not remove all the gallery plugs this is totally unacceptable as bits of dried oil, debris, swarf etc will be present, these will wreck your new crank and shells

Gearbox will have to be stripped down and fully cleaned to remove all traces unless you want these to damage your engine again that is

[cobblers]

That is an "A" series block as the alternator bracket is of the long type (for dynamo) ....

It's the big end that is different at 1.625" as opposed to 1.75" in diameter, the little ends are the same.

Remove ALL of the oil gallery bungs and get some very thin long pipe brushes, once you have got them clean.... then clean them again, from experience I have found that there are a lot of engine builders who do not remove all the gallery plugs this is totally unacceptable as bits of dried oil, debris, swarf etc will be present, these will wreck your new crank and shells

Gearbox will have to be stripped down and fully cleaned to remove all traces unless you want these to damage your engine again that is

Well spotted! Cheers for this, so it's a much earlier block than I assumed?

I was half considering buying/making a parts washer, but it seems I've pretty much got to. I'll do a proper job at least.
Would you say that perhaps my failure is caused by the block being incorrectly prepared, damaging the bearing with swarf causing it to wear and eventually spin, or due to a "baggy" no.4 conrod not providing sufficient crush on the bearing to hold it in place?

Regarding the gearbox - I took one of these boxes apart about 7 years ago at college, but it was one that had been apart about 20 times already as a demo box - is there anything (other than the obvious driveshaft seals) I should replace when stripping and cleaning it? It didn't leak oil from the selectors and seemed to work quite well without nasty noises. Was a little sloppy on the change but I assume this is because I've been used to a more modern change. Also, are there any things to bear in mind, or is it a simple "take it apart, clean everything and put it all back in the right order" situation.
There is a hell of a lot of copper in the bottom of it!

[MRA]

A parts washer just find a stainless steel sink from your local dump / scrappy cheaper and comes with a draining area oh and a few lengthes of 1" square tube or dexion (bigger meccano) multi hole framework....

Without seeing it I wouldn't like to guess at why it failed, there are various reasons why an engine fails, one of them is cleanliness or lack of the oil ways will need to be brushed through to clean them properely.

All the bearings will need to be changed as the swarf will have overloaded the races........... also for safety fit a cross pin diff.

Inspect for wear, you may well find the layshaft is failing.

OIther than that speak to John at Guessworks........... he is on this forum

[cobblers]

A parts washer just find a stainless steel sink from your local dump / scrappy cheaper and comes with a draining area oh and a few lengthes of 1" square tube or dexion (bigger meccano) multi hole framework....

Without seeing it I wouldn't like to guess at why it failed, there are various reasons why an engine fails, one of them is cleanliness or lack of the oil ways will need to be brushed through to clean them properely.

All the bearings will need to be changed as the swarf will have overloaded the races........... also for safety fit a cross pin diff.

Inspect for wear, you may well find the layshaft is failing.

OIther than that speak to John at Guessworks........... he is on this forum

Yeah, I've got a huge plastic tub, some perforated plate and an old pond pump lined up. I was offered as much "petrol/diesel mix" as I want by a chap who drained it from a car, but I'm wary of immersing a pond pump in something flammable. Machine mart do a water based dilute cleaner, but I'm worried it will be like everything else water based (Crap!)

It think it's got a cross pin diff already. I was told it had, but I'll make sure to check.

I'll definitely change all the crankshaft bearings, strip and check the oil pump and clean the oilways, and I assume I should also pay attention to the camshaft bearings too?
Oh, will I be okay re-using my 3k old piston rings providing I keep them with their respective bores?

[MRA]

Forget about pond pumps you simply do not need any pump of any kind what so ever.... just brushes, the oil gallery plugs will either need to drilled out or pulled out but removed they must be. any hole that the oil is fed through is going to be gunked up with years of filth and swarf, especially where oil changes have been neglected

Use parafin to clean and brushes..... if you aren't going to do it this way then don't do it at all as you will be wasting your hard earned / borrowed cash

[bmcecosse]

Be sure to fit a NEW oil pump - when you rebuild it!

[cobblers]

Be sure to fit a NEW oil pump - when you rebuild it!

I got plenty of pressure (100psi cold idle), even with the spun bearing so was planning on just checking it out.

After looking, they are only about £15 though. Any particular type to go for? I'm unsure of what drive system my camshaft runs, but the pump has 4 bolts (well, 2 bolts, 2 crosshead screws :S)

Edited by cobblers, 24 October 2009 - 09:34 PM.

[MRA]

When you say spun bearing has it actually spun within the conrod big end ?

100psi is too high, if you have a ball and spring throw it away and replace with the correct plunger. This will stop oil pressure fluctuation

The 2 cross heads are for takeing it apart, the two bolts fit it to the block, what is the drive like is it a flat or a round peg with a slot or a spline ??

[cobblers]

When you say spun bearing has it actually spun within the conrod big end ?

100psi is too high, if you have a ball and spring throw it away and replace with the correct plunger. This will stop oil pressure fluctuation

The 2 cross heads are for takeing it apart, the two bolts fit it to the block, what is the drive like is it a flat or a round peg with a slot or a spline ??

Yeah, the bearing shells have spun completely within the rod end, quite impressive actually - there is no evidence of the locating "tabs" on the bearings at all, and they are a good few mm smaller than they used to be. The inside of the big end on the conrod is pretty worn - deep scoring and generally a mess.

100 too high? I'll see what the dealio is with the plunger. It dropped when it warmed up, but even with one bearing hanging out and the rest pretty worn, even warm I got about 25psi. This is the reason I faffed about hoping it was the flywheel loose causing the noise before just ripping it open!

I read about the oil pumps with various bolt configs, one said "2 bolts so fit any block" so I assumed there were some 4 bolt ones, but now I know. Cheers!
I've not had the pump off yet, but it's a very recent aftermarket camshaft if that gives any clues?

Edited by cobblers, 24 October 2009 - 10:38 PM.

[Sprocket]

Most if not all recent history regrind cams will be slot/ spade drive.

Rule of thumb - Two bolt pumps are 1275, 3 bolt pumps are 998