First Time Engine Rebuild

[edd_barker]

HOME OF THE ROOKIE ERROR, THE SCHOOLBOY MISTAKE AND THE POWER OF HINDSIGHT.....

Hi all,

Stripped down my first A-Series 1098 engine today, with the intention to rebuild with a 12G940 head, and eventually split the manifold, bigger carb etc. I'll be using the workshop manual, various youtube videos and this forum to gather all the info I hopefully need, but I'm sure there will be plenty of questions coming as well. Starting with...

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This is where the flywheel has been rubbing, what could cause this? apart from the obvious answer that it wasn't seated properly, but all the bolts were tight. What should I check to make sure this doesn't happen again, bearing in mind that this stage is VERY far away!

2. I want to order some vernier callipers to check wear on crank and cam etc, anyone recommend a brand? they're cheap on fleabay, which I'm also guessing means not very precise. I'll get the machine shop to measure bores, there's some corrosion so I'm expecting a rebore.

3. Any tips on sources for new engine parts? I've found loads of 'new' parts for other parts of the car aren't very good, so I'd like to ensure that piston rings, bearings, core plugs and everything else I'm changing is top quality.

Any other suggestions, tips or information I should be absorbing please feel free to point me in a direction, It'd be much appreciated.

Many thanks,

Edd

[bmcecosse]

Is the ring gear squarely mounted on the flywheel? I suppose severe wear on the main bearings could do it - but it would need to be very bad indeed. Perhaps very badly worn thrust washers - is there much endfloat on the crank? Or (least likely I think) a bent crank..... If you refit the fly and rotate the crank - does it go anywhere near the cover ??

[philthehill]

As regards the wear to the oil pump cover:-
I suspect that the contact between flywheel and oil pump cover is caused by wear of the thrust washers allowing the crankshaft to move forward.
The crankshaft should only be able to move fore and aft by 0.002 - 0.004".
If the thrusts are worn to that degree I suspect that the rest of the engine is not looking good unfortunately.
Phil

[edd_barker]

Oh dear, I didn't check at the time, the engine is now in as many bits as its possible to be...

I could try and reassemble but I'm not certain I kept all the bearings as I was expecting to replace them all.

I could post pictures of the thrust washers when I'm next working on it? there are two on the centre main bearing yes?

I assume the machine shop can check if the crank is bent? I bought the engine as running but in need of rebuild, from a source I trust.

I will also examine the flywheel ring gear.

Thanks!

[bmcecosse]

It's not unknown unfortunately for the thrust washers to be fitted 'wrong way round' - which of course wears the devil out of the washers - and the crank.....

[The vast minority]

Great project, Be sure to keep us posted

On the subject of measurement,
Intentially speaking in hundredths of a MM and thousands of an inch.

.01mm is a lot less than .001inch which is a "thou" so use the metric scale to test the caliper. A thou is .0254mm for ref so testing a caliper on imperial is not the way forwards unless it has 10ths of a thou on the scale but we won't go there....


You are probably talking about cheap digital calipers, these are not vernier calipers. Vernier calipers have a graduated vernier scale, the calipers you are likely alluding to will probably have a digital readout. I've got mitutoyo digital ones which are not cheap but they are from a reputable manufacturer of metrology equipment the world over. I've also got vernier calipers as well. These are great because the battery never dies and they last forever with no electronics to fail.

Still, the cheap digital ones are nearly always accurate to the resolution the have. Just wipe the faces, bring lightly together and zero the reading. Operate it across its range,try it on a slip block, and so on. If it measures a 75mm slip block to 75.00 and a 150 block to 150.00 and reads zero again when closed then it's a good one but only measures as accurately as the operators skill allows.

HOWEVER Neither the cheap one or the expensive one is ideal for engine reconditioning alone But they do have a lot of uses. For accurate and reliable engine work, particularly in the bores, you need micrometers, or a spring bore gauge and outside micrometer to measure the OD of the bore gauge after use. Outside measurement with a caliper is possible with a skilled touch but inside a bore, because of the internal radius of the item you are measuring the results are at best only a guide. The calipers will be relief ground to minimise the problem but to be accurate it would need to have a needle point on the internal anvils which would also have to be hardened and would therefore break very quickly.

Other measurement devices are available but beyond the scope of any DIY mechanic. Air gauging for example, telecentric shaft scanning and so on.

Al

[philthehill]

Oh dear, I didn't check at the time, the engine is now in as many bits as its possible to be...

I could try and reassemble but I'm not certain I kept all the bearings as I was expecting to replace them all.

I could post pictures of the thrust washers when I'm next working on it? there are two on the centre main bearing yes?

I assume the machine shop can check if the crank is bent? I bought the engine as running but in need of rebuild, from a source I trust.

I will also examine the flywheel ring gear.

Thanks!

Whilst there are two opposing thrust faces there are four thrust washers.
Two fit into either side of the block centre main bearing housing and the other two fit either side of the centre main bearing cap.
Phil
http://www.ebay.co.uk/itm/Austin-Rover- ... xyOJxSLw7-

[edd_barker]

Thanks for the replies, and Al, for the definitive guide to measuring calipers! I only really want to check wear on cam and crank so I assume a decent set of digital calipers will suffice? My local engineering consumables store has a set it says are decent. I don't think I have anything precisely machined that I can check their calibration with, will a bit of 2" by 1" timber do? (joke!)

I am back in the garage tomorrow so I will photograph the thrusts. It is entirely possible that a mistake has been made, when I removed the pistons they were all numbered, but not in the correct order, so whoever has been poking around in there before was perhaps not the brightest. Does it matter which order they go back in if I am reconditioning, new bearings, rings etc?

I am assuming my work list looks something like:

Block - skimmed as different head & gasket to be used, 1275 head. Bored to next oversize. New core plugs, cleaned etc.

Cam - Haven't figured out how to replace these bearings yet.

Head reconditioned and bolted on.

All new gaskets, lock washers and tabs, new bolts?

Paint shiny green

[bmcecosse]

If you rebore the block - you need new pistons and rings. I wouldn't touch the cam bearings unless the engine has been run to a 'seized' stop with no water and/or oil. You'll almost certainly need a crank regrind with bearings - and a new oil pump of course. Worry more about the cam followers rather than then camshaft. And new timing gear and chain - may as well go duplex - or the Mini set up with rubber tensioner. Budget about £5/600 for the work - and that's assuming you assemble it yourself. Meantime - drop the crank back in with centre bearing shells and thrust washers, and measure the end float.

[edd_barker]

Aaah ok, I thought I could get away with just larger piston rings! That brings the price up somewhat. I will get some quotes from the engineers and go from there. Thank you

[edd_barker]

From where do I measure the end float? I assume this is poking a feeler gauge in somewhere. I have also probably mixed up the bearings, will this affect the reading if they go back in a different place?

Thanks

[bmcecosse]

Won't matter - just fit the thrusts and any pair of shells - and pull/push the crank - should be no more than 4 thou. I suspect your endfloat will be a LOT more than that! Measure with feeler gauges. If you really want a caliper gauge - Lidl/Aldi have perfectly satisfactory items regularly. Can you show us a picture of the crank journals and the bearing shells? Just let the Company doing the regrinding do the measuring....

[edd_barker]

So, in the spirit of checking the obvious last...it was the ring gear on the flywheel! All over the place, I assume that I can have this removed and fitted correctly by the engineering shop.

My attempts to measure the crankshaft end float were futile, I reassembled and could find no movement fore/aft in the crankshaft, even tapping either end with a rubber mallet. Trying to insert a feeler gauge into the gap between the thrusts, I couldn't get anything in there, going down to a .015. Am I making a mistake, could someone describe in idiot detail how to measure?

Here are the photos of the wear parts for your kind visual assessment. I think I will take the whole lot to the machine shop and get them to have a good look.

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Thrusts are already oversize at .03, do I just fit replacements of the same size?

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Pistons are already 030 oversize, I think the crank main bearings are 020 so it must have had a fair bit of work in the past. fingers crossed its still economical to rebuild it once more!

thanks,

Edd

[philthehill]

Those thrusts do not look too bad, neither do those crankshaft journals and shells.
Get the machine shop to measure the journals to make sure that they are not oval.
If not oval - on the face of it I would just replace the thrusts, big end and main bearings shells with new.
Clean that front main bearing up with a little bit of very fine rose paper making sure that you only rub round the journal not across it.
Is the scoring of the oil pump cover new or old?
If the engine has been rebuilt in the past it could have happened with previously worn thrusts.
Phil

[edd_barker]

^Phil^ You must have skim-read, it was the flywheel ring gear! It's on very wonky, I'm not sure how this has happened but I will take it to the machine shop and see if they can re-fit it for me. It makes a hell of a noise scraping past so god knows what the previous owner thought!

I will get the engineers to assess all the items and replace as necessary. I can't feel a wear ridge on the bores either, although there is visible corrosion, so maybe a hone and rings and I will get away with it!

Thanks,

Edd

[bmcecosse]

As above - the shells and crank look fine ! I wouldn't be bothering with a regrind on that. And 15 thou was never going to get in there - maximum of 4 thou !! The ring gear (is it definitely the ring gear - or is the flywheel distorted ?) - if it has moved - I think it would be unwise to refit it - but if they do - I suggest it should be secured with a few short runs of weld round the edge to make sure it doesn't move again. Or - break it off, (drill a hole then sharp chisel) and fit a new one - which involves heating it up in the oven at max setting - with the flywheel in the freezer overnight.

[edd_barker]

Sorry I meant 1.5 thou (.015), which is the thinnest one I have, like a bit of paper!

[bmcecosse]

One point five thou is 0.0015..... Clean everything carefully = there MUST be a tiny bit of end float.

[edd_barker]

OK, I will have to check when I get back in the garage! It was my smallest feeler gauge, almost like tin foil, it was so floppy I struggled to find anywhere put it in! (insert appropriate humour here).

Just a standard set of feeler gauges that I use for points, tappets etc. But I'm assuming that if there was no end float the crank wouldn't turn at all? Another query for the machine shop.

I found this on the bench whilst I was moving the block around and using a hammer/drift to remove the core plugs:



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[frame][/frame]

Looks like a cross between a bullet and a cam follower, any ideas what it is and where it came from?! I haven't scoured the workshop manual yet. It could be from something else but the bench was clear...

I also removed this bolt:

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I'm guessing its a drain for coolant from the block? Just to make sure I get the correct copper washer to replace.

Many thanks, everything is going into the engineers Monday so hopefully won't be long till I can start putting it together.

I think I will start with the standard carb/manifold etc to make sure she runs, before investing in HIF38 and all that malarky.

Edd

[Chipper]

Looks like the sump drain plug to me.