Diesel Crank replacement

**smithy010** · 04-08-2006, 07:17 PM

Ok.
I've been thinking about this for a while, but i can't excatly work out what the best way is.

I've got this diesel engine from the loon, and it needs a new crank. I've been thinking of the best way to take it out and replace it without pulling down the top end.

The procedure thus far, that i have nutted out.
In parentheses i have put the possibly problems with this method.

With engine removed.

1 Remove flywheel
2 Remove Driven plate 6 bolts. Mark Flywheel position. (Problem: If i use a different crank in reinstallation, the new crank will not be marked)
3 Lock Camshaft and injector pump
4 Remove front sprocket, timing belt, seal plates, etc.
5 Remove sump, oil pump.
6 Mark Conrods and big end bearing caps 1, 2, 3, 4 (With crankshaft remaining in one position, it will be hard to access each conrod- can i turn the pistons over with the valves locked in position?
7 Remove big end bearing caps.
8 Push pistons slightly up cylinder. Fit pieces of plastic tube to bolts.
9 Remove main bearing caps, remove crankshaft.

The problems i have are with marking the conrod caps, and possibly having to turn the engine over to remove each conrod.

Should i be worried, or am i being a moron?

Also, when i am retiming the crankshaft to TDC, a dial gauge would normally be used on the top of the piston right?
If i've still got the head on, how can i do this? It will be too inaccturate to do it on the crank somewhere..

**Golf Loon** · 04-08-2006, 07:41 PM

You are mostly right. Turn engine upside down. Remove sump, flywheel and other bits.

Remove the bearing caps. Put the crank in and once the new one is in, you can set tdc.

On a petrol you stick a screwdriver down no. 1 sparkplug hole. When its at the top of the stroke its at tdc. On a diesel you must have to remove glowplugs?

Is the diesel a non interference motor? I know the petrol is.

When you have set TDC, refit the flywheel and you are set.

**gtimk5** · 04-08-2006, 07:46 PM

"Definately not a moron Smithy. We are to give out advise. No need to mark the flywheel as the bolt hole are offset so the flywheel will only go in 1 position Position the crank with the pistons half way up/down the bores That way you should be able to undo the caps without rotating it. You will haver to reset the cam/pump timing afterwards. You got a manual? We can explain how to reset if you need to know. There are enough of us here to explain!

**gtimk5** · 04-08-2006, 07:49 PM

Originally Posted by Golf Loon

You are mostly right. Turn engine upside down. Remove sump, flywheel and other bits.

Remove the bearing caps. Put the crank in and once the new one is in, you can set tdc.

On a petrol you stick a screwdriver down no. 1 sparkplug hole. When its at the top of the stroke its at tdc. On a diesel you must have to remove glowplugs?

Is the diesel a non interference motor? I know the petrol is.

When you have set TDC, refit the flywheel and you are set.

Hey Loon, I wax 3 minutes behind you mate! The deisels are an interference motor

brackie · 04-08-2006, 08:42 PM

Smithy.... You'll need to check piston protuberance before you order a new head gasket. A dial gauge would be the go, but if you don't have one then a good straight edge and feelers will give you the amount that the pistons stick out of the block. It's very important to get it right. There's a range of notched head gaskets and one will suit. Also importantly you must torque the conrod nuts properly. Check for bearing crush by torquing one nut and then slipping a 2 thou feeler under the opposite end of the cap. If it gives clearance all is well. Cleanliness is next to Godliness in all of these operations

If you're re-ringing make sure that the ring gaps are offset and that none are on the thrust side of the piston. Rings will take a long time to bed in (assuming the bores aren't oval in which case they won't bed in at all!) so lug the motor hard over the first 500km or so. As Andrew says it be as well to check injection pump timing too. I assume a new belt is the go.

**smithy010** · 04-08-2006, 09:30 PM

Thanks, you people are very helpful.

Brackie, i'm not doing the top end, so won't need to worry about the head gasket, however the engine supposedly has had a ring job, so i will definitely take your advice for running in.

If i lock the pump and maybe even camshaft before i take the cam belt off, all i should need to do is time the crank to TDC cyl 1, then put the belt back on.... is it that easy?

I have a tractor manual, and while it has good pictures, it's pretty crap explanation wise... all it says is use VW tool no.1234xxx.. which of course i don't have...

Quick question while it's on my mind.... like the loon said about sticking a screwdriver in the spark plug hole to find TDC- can i do the same with the glowplug hole?

brackie · 05-08-2006, 06:55 AM

Originally Posted by smithy010

Thanks, you people are very helpful.

Brackie, i'm not doing the top end, so won't need to worry about the head gasket, however the engine supposedly has had a ring job, so i will definitely take your advice for running in.

Should be Ok. JUst make sure everything's @ TDC before you start.

If i lock the pump and maybe even camshaft before i take the cam belt off, all i should need to do is time the crank to TDC cyl 1, then put the belt back on.... is it that easy?

You MUST lock both. There's a locating hole in the engine front plate behind the injection pump sprocket. Yesterday I looked for the locking pin that I made so that I could give you the dimensions but it's gone AWOL. Can't remember who I lent it to

The cam can be locked easily by grinding a piece of flat bar a couple of thou over thickness and carefully hammering it into the slot at the rear of the camshaft.

I have a tractor manual, and while it has good pictures, it's pretty crap explanation wise... all it says is use VW tool no.1234xxx.. which of course i don't have...

Join the "Special Toolless Club"

Quick question while it's on my mind.... like the loon said about sticking a screwdriver in the spark plug hole to find TDC- can i do the same with the glowplug hole?

No. The precombustion chamber is just that... It's above the block and inset into the cylinder head. I guess that a piece of wire bent and poked into the glowplug hole could find the piston crown as it comes up, but if you have it at TDC at the flywheel you needent bother. Both #1 cam lobes should be pointing up.

**Golf Loon** · 05-08-2006, 10:07 AM

Originally Posted by gtimk5

Hey Loon, I was 3 minutes behind you mate! The deisels are an interference motor

Nice that we all want to help.
Dont take the head of smithy. The guy who had that engine definately rebuilt the top end and did the rings.
Good that the diesel guys can talk you through the tdc steps.
Sounds like if you lock the top end, the bottom end will take care of itself.
Di you get bearings and a petrol crank? That will answer a few questions in itself

**gtimk5** · 05-08-2006, 12:13 PM

Not sure if brackie still has that spare maual. Be a good idea to strike a deal on that if he has. The Bentley manual shows the timing very well and has lots of other things in it that you might need to know.

**smithy010** · 05-08-2006, 05:29 PM

Originally Posted by brackie

There's a locating hole in the engine front plate behind the injection pump sprocket. Yesterday I looked for the locking pin that I made so that I could give you the dimensions but it's gone AWOL.

Haha, don't worry, i made up one of those locking pins on my old man's lathe when i was at home picking up the crank outa my old 1600 petrol engine.
Still undecided as to whether i will use the petrol crank. I'll check to see the similarities to the diesel one first. I suspect it will be quite similar. The fact that the engine has 5 main bearings, makes it pretty unlikely that the crank will bend.

I also made up a cam locker.. it's not ideal, but i think it'll do the job. It's a little saddle that clamps down on the middle of the camshaft using the tappet cover bolts either side. If i give it firm pressure, but not too much, it shouldn't cause too many troubles.