Rebuild 1980 Volvo MD11C Diesel Auxiliary

[ntheyer]

I have my engine pulled and at home now and half disassembled (from the previous owner). I am rebuilding the engine, but frankly, am not really sure how to go about doing it. I have the parts on order, but wonder, what do I actually have to do? Just replace parts? I know there is some machining to be done somewhere... what gets machined? How do I remove the rust buildup from the intake manifold cooling galleries? Where should I begin? I will attach some pictures.... Thanks.

[Blue Eagle]

Hi,

Firstly: Don't lose heart. It's a process. Daunting at first, but not impossible with a little patience, reading, guidance and common-sense.

The first step to take while you take stock is to contact Volvo and ask for the workshop manual (not the "operator's manual") for the engine. If you get stuck, I have a copy of a copy that I can mail you if needs be - in fact it may be even more use scanned, but I'd rather not "fracture" Volvo's copyright if I don't need to. On the Volvo Penta website http://www.volvo.com/VolvoPenta/Global/en-gb you'll find the operator's manual for all of their engines, plus the workshop manuals for some (albeit not this one).

Secondly, Please, PLEASE put a bit of cling film (saran wrap to you) over the injector pump feed pipes and secure with a rubber band... if you get dirt in there, you won't find out until the engine's rebuilt and reinstalled, and you'll then regret it for a looooooong time (!) - diesel fuel injectors absolutely detest dirt.

Third; You need to take lots more pictures from lots of angles. Save and label them. Your engine looks like it's in much better condition than mine was, but having got it out and halfway dismantled, you'd be very unwise IMHO not to strip it right the way down and clean the grease and grime off every last inch of it before repainting (I always use hammerite - it's the best) and reassembling.

Fourth: having dismantled everything else, you need to check the camshaft and crankshaft end-float, before removing both and eyeballing the camshaft bearings for ugly signs of wear (discoloured or copper-looking patches especially). If the camshaft bearings need replacing, you'll need to get a reputable machine shop to do it as the shells have to be drifted or pulled into place, then reamed out to size.

Fifth: Please do take the crank shaft to a good machine shop to be measured and re-fitted as necessary - as outlined in my other post. Not to do so at this point would really be asking for the big ends or mains to develop a knock shortly after refitting - meaning you'd have to pull the whole thing out and start again - Gaaah!

The good news is: if the shop comes back and tell you that the journals are fine and within spec. you can dispense with the re-grinding, and if you handled the bearing shells sympathetically, you might even get away without replacing the shells either.

Do be careful to mark the big-end bearing caps and the con-rods before you take them off the crankshaft. I use a centre-punch and tap one dot on the side of each piece for cylinder No.1 (nearest the flywheel) and 2 on each for No.2 cylinder (work through the inspection hatches to accomplish this easily). This not only tells you which bearing cap and con-rod belongs together, but also which big-end journal they belong on and which way round they go on that journal. This is especially important if you're not replacing the bearing shells as each set will have worn to its own journal, and must go back on the same journal that it came off.

More later.... do get that manual!

Best,

Blue Eagle

[ntheyer]

Thanks for the great replies. I have the manual and all of the parts ordered. Should be here on Monday. The plan is to take the enigne apart completely and then repaint and rebuild. I already bought every seal, gasket, bearing etc. that can be replaced. Basically, if it wears, it's getting replaced or machined. Just like you said, I don't want to reinstall and then have any issues. I expect it to be 'as new' and to run for twenty years without issue when I'm done. I'm sure the shop manual will give me plenty to read once I get it. I'll let you know as things progress.

[Blue Eagle]

Cool!

While you're doing the rebuild, can you do me a favour please? Could you note down the make and model number of the starter motor for me?

I'm pretty sure mine's a bosch, but the number had corroded off - and although I had it rebuilt locally, it's a bit... wheezy.

[ntheyer]

Ok, I'm making some progress. My question is how did you secure the engine to remove the flywheel nut? Is is reverse thread also? My starter is pretty rusty, but I'll get the make and model info off of it tomorrow.

Thanks.

[Rockter]

I can't imagine what all that is going to cost.

Anyway, the flywheel nut will come off readily with an air-operated impact driver. Then you will need a puller to get the flywheel off the crank. It can jump off with some force, so hands and face clear!

You will need a torque wrench for the re-assembly also.

Make sure the new exhaust gaskets go on the right way. In the semi-darkness, I got one of them the wrong way round.

The exhaust manifold is brittle.... be careful with it. I wasn't careful enough.

I have never done a plain bearing crank rebuild. Blue Eagle seems to know it well.

It looks like you had difficulty getting the nuts off those two cylinder head studs. I never could. I had to buy a new stud.

Get all that muck off it. Vacuum cleaner, then scrub, scrub.

You are going to need a micrometers to check your bumping clearances. The manual will explain.

[cardiacpaul]

the piston pin bearings on the ends of the con rods look bad, you'll have to have a machine shop replace (press) those and fit the pistons too. How do the pistons look? are the skirts scored? Do you know, or have you checked the bores on the cyls? are they out of round? if so, how much? You may have to have them bored. if thats the case, then you're looking at oversize pistons/rings....
you'll have to have the machine shop put in the new cam bearings and while you're there have them grind and balance the crank, and have them fit the crank bearings and thrust washers, while they're right there, have them put in the front and rear main seals. You don't have, nor do you want to buy any of that equipment.

[cardiacpaul]

after a second look at the piston pin bearings, you really do need to take the crank in. they are badly worn and the pin side of the conn rod is the one with less to do. (range of movement is much lower than on the crank side)

IMHO, you shouldn't have bought con and main & cam bearings yet, the cam & crank really should be "turned" and balanced. If they remove any material from the crank, you'll be needing undersize bearings.

[Blue Eagle]

Originally Posted by ntheyer

how did you secure the engine to remove the flywheel nut? Is is reverse thread also?

Hi, - securing the engine: I lashed it against one of the support pillars in my boat club's covered garage - it's about 18" square, so limited chance of its falling over.

I'd be interested to hear if one of those air-driven impact wrenches manages to remove your nut - I had to cut a flat off mine (carefully so's not to damage the thread on the crankshaft) and then club it with a four-pound hammer and cold chisel to get it to shift. My 200lbs on the end of a 4-foot lever wasn't enough torque to shift it!

The thread is normal, ie: right-handed - undo anticlockwise.

cheers,

Blue Eagle

[Blue Eagle]

Originally Posted by cardiacpaul

you'll have to have the machine shop put in the new cam bearings

Agreed - if you need them - use a dial-test indicator on the back of the cams through the top of the block, and try to rock the shaft up and down to see how much play you have - or get the machine shop to check for you.

Originally Posted by cardiacpaul

and while you're there have them grind and balance the crank, and have them fit the crank bearings and thrust washers, while they're right there, have them put in the front and rear main seals. You don't have, nor do you want to buy any of that equipment.

Agree with the grinding - you shouldn't need rebalancing as the journals should have worn evenly, but see what they think - beware some folks will try to sell you a rolls royce when you went to buy a moped - so do make sure in your own mind that the work needs done - this is a marine diesel engine remember, not a highly stressed sportscar engine.

Do ask them to press the front (No.1) and back (No.3) main bearing shells home into the front cover plate and engine block respectively for you - once you know what size you need. I drifted mine in with a wooden block and a rubber-headed mallet - but I've had lots of practice and I was very careful how I did it - I don't recommend this route to anyone with a machine-shop alternative - or a long piece of threaded bar and some big bicycle washers to pull them in. If you elect to do it yourself however, you have to fit both halves of the bearing shell at the same time, line the locating tangs up with the detents in the casting, and oil the backs of the shells to help them slide home. They must go in absolutely perpendicular to the casting however, otherwise they'll get jammed - and you won't be able to remove them without damaging them.

The centre bearing on the MD11C goes on in two parts, so no pressing needed - do torque the bolts on the big cast bearing cage up to spec though. The thrust washers go either side of the rear engine block casting which holds No.3 main bearing, so again, no need to get the shop to fit them (but do be careful to get them the right way round (notched faces outwards, bearing the thrust) and to engage the tangs in the locating detents, when you re-fit the crankshaft.

Do ask them to press home the crankshaft main seal if you're not confident using the wood-block method I describe above (you'll need a nice flat piece of 1x4 or 2x4 hardwood, about 6 inches long) - the rear end of course opens to the bellhousing and the rubber transmisson tripod and seals agains the gearbox, so there's no "git" seal to worry about - on the engine block itself.

cheers,

B E