Adjust crankshaft endfloat or full rebuild?

[cres1964]

First attempt at a "rebuild" for me on my 1990 2.1 DJ engine.
I have the engine on the stand, heads off and pistons out and I'm trying to decide if I need to crack the case open or not.
The van was running fine all apart from excess oil in the exhaust causing an MOT fail and a pretty pattern up the tailgate after each drive. I've ended up honing the cylinders, rings etc and while I'm there lapping the valves, replacing studs, water and oil pump etc.
With the engine in its current state I have measured the crankshaft end float to be around 1mm and I'm supposed to have around 0.1 - 0.15mm but I don't know if I should be measuring this without the pistons and cylinders installed.
If the pistons and cylinders don't affect this measurement and I really do have 1mm float should I be looking at the shims behind the main seal or is this such a big discrepancy from the acceptable values that I should be splitting the case and inspecting / renewing all the bottom end bearings?

[TwinTurbo]

Is there any slop in the conrods. can you determine the condition of the camshaft lobes.

[maxstu]

Hi cres1964,

I've recent finished a complete 2.1 engine rebuild and getting the correct parts is very difficult.

Yes you can measure crank end float without pistons and heads attached. But what method are you using to measure at the moment? 1mm is not good. If you can, posting some photos helps the forum support your rebuild with correct advice.

First things first. A few forum users recently have started similar work claiming their engine is a DJ. Yet photos show otherwise. Often the engine case has been over stamped (happened to me) and internal are DG or running SS/MV pistons.. To help us help you, would you please confirm you definately have a DJ engine? Piston crowns is the easiest confirmation. Plus higher compression readings on a test.

Three things to consider.:
Did you do a compression test before stripping?
And did you do an oil pressure test before stripping? Both will indicate health of engine and how deep you need to go.

Secondly, lapping valves may help, but may not be the immediate answer for stopping oil getting through. The valves, seats or guides in the heads may be worn. It could also be caused by worn piston rings (your replacing) or worn out and scarred cylinder sleeves. You need to accurately measure lots of things to determine whether to reuse or replace.

Lastly, the 2.1 uses a pair of thrust bearings at the end of the crank. One is inside the case and the other against the shims. To replace you will have to split cases. They could be badly worn and causing excessive end float. But they tend not to wear.

[cres1964]

I bought the van as a 1.9 and until I saw DJ stamped on the front of the engine i assumed it was so! Here are a few pics I've taken so far and you're right working out what engine I've got is probably a good first step lol!

https://photos.app.goo.gl/RpJY68WpV4haJTbD9

This is a public Google photo album that I will update with any further pictures, this allows me to share the full size images with you rather than compressed versions for the web

I did do compression tests before starting my strip down but not oil pressure, my intention was just to do the heads but now seeing this endfloat I don't know if I need to go further into the belly of the beast or not. Compression was 70 dry on 3 cylinder's and one down on 50, all went up by 30psi in the wet test which made me think piston rings. There was some light scarring in one cylinder which is not enough to catch a fingernail even before I started honing.

[maxstu]

The photos show MV/SS pistons.

This is a DJ piston. Note the smaller crown

[maxstu]

Healthy compression should read around 150-160 psi.
Or 10-11bar.

[cres1964]

That is very helpful thank you! So does this mean I have a 1.9 engine? Does the engine code on the block mean nothing? Where do I go from here lol. I ordered piston rings for a DJ engine which appear to fit, will they be ok? I used to think I had a dg engine, can't remember where I got that info, possibly the v5, but I suppose I should have worked out which engine I had before I started taking it apart but in fairness it was all covered in so much oil it looked like a moon rock when I started lol. What is the definitive thing that tells me which engine I have as I need to refer to the right values in the Haynes manual for tolerances etc?

I'm aware the compression was low and I'm hoping the rings / cylinder honing / valve lapping will help with that.

And back to my original point I've measured the endfloat with shims / calipers I've got a dial indicator on the way though. Even if my measurements are not 100% accurate I'm certainly nowhere near the 0.15mm tolerance I thought I was aiming for when I believed my engine to be a DJ engine. As you can see from my photo album shown in the last post I also have a lot of dried coolant gunk in where the cylinders go, I've cleaned what I can but didn't want to go too aggressive with it or if worries the debris will all make its way into the bottom end. Should I be splitting the case to address the endfloat and cleaning it or is this a can of worms I don't need to open....

Thank you all for your help is very much appreciated

[maxstu]

Out for three hours walking dogs. Will reply on return

[cres1964]

Three hours!? You must have some very happy dogs!! Enjoy the sunshine and thanks again!

[PaulFDennis]

I think the DJ and DG cylinder bores are the same. The DJ has a longer stroke and thus slightly larger capacity.

[maxstu]

I think the DJ and DG cylinder bores are the same. The DJ has a longer stroke and thus slightly larger capacity.

Yes. The same sleeves or cylinder bores. But different cam, crank and pistons.
A DJ crank will fit inside a late DG1900 Engine case. But may need a bit internal dremel grinding. However, there is more to it than just that.

[cres1964]

But if I have mv/ss pistons is that going to mean I've got a 2.1? The displacement is only for my own understanding, the bit where it matters is can/should I adjust the endfloat with washers or do I need to split the case and look for the cause of excessive endfloat inside the crank case?

[maxstu]

Well you do have 2.1 pistons. They are the low compression versions. But of no gain if mated to a 1.9 crank and cam. And that's where you need to go, unfortunately; plus a keen ability to pay out, and willing to absorb a lot a disappointment, to be honest.
I have a spare 2.1 crank here l could measure so we can compare. If you decide to split engine, keep the conrods attached to crankshaft for now
2.1 rings are the same for DJ/SS/MV. So yes they will fit. But l would measure sleeves with an internal bore gauge to see if they are fit for service. I see some damage markings in one sleeve (nice honing by the way). Otherwise pointless fitting new rings.
The heads look okay and not much valves receding involved. The exhaust valves wear before inlets.
Cylinder head studs condition is paramount. What l assumed was excellent was readily rejected by a pro engine builder. No pitting whatsoever is the game.
The cases are also important as they compress the crank bearings leading to good oil pressure. Worn cases will not last long and end in premature engine failure.
So so much more to consider

[Aidan]

even with pistons out it is possible to measure stroke and determine if it's a 1.9 or 2.1 crank, 67mm for 1.9, 76mm for 2.1
The DJ rings are the same as the MV rings so you can use those on the pistons you have
Is the case late or early ? Cast part number on it will tell us
Given its a bitza it is good to pin it all down for certain

[cres1964]

Continued thanks and everlasting gratitude for any and all advice, we are working our way though a mystery I didn't even know I had until I posted here lol.

So I have measured the stroke from a datum (radiator bracket) spanning the crankcase and measured down to the top of the con rod at tdc and BDC using the depth guage on my calipers and I get a stroke of 75.2 so I'm going to assume we are looking at DJ internals with the wrong pistons (mv/ss). Does this sound a reasonable assumption or are there more things to check before that can be said?

The case number stamped on the block below the oil breather tower is DJ009564* .... AHH just noticed the asterisk at the end (only ever read the first two characters before, this is a reminder to me of how lazy I can be lol) does that mean this is a factory rebuild which might account for the fact I seem to have a mix of bits in here? Is that what is ment by a bitza? Just bits of whatever VW (or whoever) had around at the time?