A rank amateurs attempt at a DG rebuild...

[bustrucket]

About a year ago I bought a "Y" reg T25 camper with the plan of making it a running project, but quickly found out that was wildly optimistic for various rust related reasons...Also, it had the legendary 1.9 DF engine, which even when new probably wouldn't have been impressive, but by the time I got hold of it even the slightest slope was a major struggle.

So it was taken off the road for some rust repair and I had the bright idea of replacing the DF with a "recently rebuilt" DG I found on eBay. Only problem being, it had no compression on one cylinder. Thinking this would probably be a simple fix, I bought it anyway, only to find that something had got into two cylinders and chewed the pistons and heads up, and the other head was cracked

Not having learned my lesson, I ended up buying two more engines, a seized DG and a DJ with a bad big end. Typically, both of these ended up being mostly scrap, I couldn't salvage much in the way of usuable parts.

Long story short, after endless procrastination, I've come full circle and decided to rebuild the first DG after all. I have (hopefully) accumulated all the parts I need (plus a lot more), and this site has given me at least some clue how to proceed. Here goes...

[bustrucket]

Sadly, I don't have any pictures of the "rebuilt" DG from when I got it, but I dismantled it fairly quickly. It came apart very easily, and was actually fairly clean inside.

The pistons were non-VW, and were all chewed up anyway, so they were discarded. It also had a 3-bolt cam and gear (air-cooled?) and the heads were chewed/cracked. So really only the case and crank were salvageable here.

Here's the case after cleaning, ready for test fitting the cam and crank at last:



And the crank, ready for the gear to come out the oven and refit:



Turned out not even heating the gear up made it easy to fit, it just stuck almost immediately. Fortunately I had prepared for this - M20 fine threaded rod and a scaffold coupler as an emergency press. It still took some effort, but went on eventually!



Crank assembled and test fitted, turns very smoothly:



I couldn't find out what size the 3-bolt cam gear was on this engine - it had a P/N of 113.109.111A but I couldn't find this anywhere, it looked like a Beetle part? Anyway, by this time DG cams were almost unavailable, so I took a chance and bought the only size of DG cam that was available, which was a zero size.

Test fitting this NOS cam (holding my breath, everything crossed, etc):



And...it had audible and visible backlash (about 0.08mm if I'm measuring correctly). Ah well. Fortunately I have some other cams to try:



I have two zero size gears (one old, one NOS), a +1 from the DJ, and the mystery 3-bolt gear.

Both the zero gears and the 3-bolt have obvious backlash

However...the +1 seems to have none! And it doesn't lift out when the crank is turned backwards, so I assume this engine needs a +1 gear?

Cheers

David

[pandp38]

Looking forward to see how your engine rebuild goes. Did you have any problems when stripping it down ? eg. head studs snapping etc

[bustrucket]

Surprisingly no, every stud came undone pretty easily! I suspect this might have been because the engine was rebuilt not that long ago right enough. I did have one of the case studs snap when dismantling the DJ, and when drilling it out he drill wandered unfortunately, but that engine was in a sorry state before I got my hands on it so hopefully no great loss...

While I think about how I'm going to swap the cam gears around I thought I'd clean up some more parts from the pile. Pistons first:



First two cleaned up quite nice:



And since they turned out so well I decided to do the same for the DJ pistons and the conrods as well:



Here's a question - has anyone ever fitted DJ pistons to a DG? I was thinking the higher compression would increase output a bit, but then timing would probably need retarded a bit to prevent pinking which would maybe cancel out any potential gains...

Cheers

David

[bustrucket]

Scratch that question, looking at the pistons side by side I can see why it wouldn't work!

[itchyfeet]

Scratch that question, looking at the pistons side by side I can see why it wouldn't work!

yes indeed, different height.

[kevtherev]

Great post
I love it when folks post up their work

[DoubleOSeven]

You've earnt your spurs already with all that bad luck. Good Luck with your build - following with interest. Maybe able to help too, when it comes to set up. Is it worth sending the carburettor off for a rebuild whilst engine work going on?


Sent from my iPhone using Tapatalk

[itchyfeet]

Not heard of anybody fitting a DJ cam to a DG, I wonder if it's good or bad.
Gut feeling is it would breathe better so good but I could be wrong.

is the DJ crank any good?
if is and you have a good set of DJ pistons you can build that late DG case as a DJ.

[bustrucket]

Good point on the carb, I've been concentrating on the bare engine parts so much I've been neglecting the ancillaries!

I'm afraid the DJ cam is shot, the lobes are pretty bad



The plan here is to drill out the rivets and swap the gear over to the NOS DG cam as described in the "WBXLog", I'm still thinking through how I go about that though, at least I should have access to the required tools at work with some luck.

As for the DJ crank...it had a bad big end bearing. How bad? This is what was left of the bearing:



So I got the crank reground to .25 undersize main and .50 big ends a while back, but on close inspection I'm not sure the job was done right...maybe I could get your opinions on this?

Sorry for the poor photos, but this hopefully shows the centre bearings, with the grooves still present on either side of the bearing surface:



But from the other side, the grooves are almost flush with the surface? I'm no expert, but this suggests it was ground off-centre? All of the bearings look similar:



Even if the crank is good as-is, as far as I know DJ cams are unavailable now anyway! This is a good part of the reason I decided to stick with the DG for now, although I would have much preferred the DJ for various reasons, including a longer term plan to put a LPG system in. Best laid plans and all that...

Cheers

David

[itchyfeet]

If you are in FB there is a page called VW T3 waterboxer wasserboxer, join it and post the crank pic and question, some of the best WBX experts are on there and will love to comment ( the only reason I joined fb) If you are not on there I can ask for you.

My feeling is grooves are cast in and may not be concentric to the ground surfaces so may be no guide, when you remove 0.25 the depth of the groove may become more obvious however there may be ways of checking.

Cams for DJ can be reground, Andrew at campershack has had them done by Newmans cams, they have the DJ profile mapped from a good cam.

some DJ cams may also be available from VW classic parts.

Time you joined the club?

[bustrucket]

Thanks itchy, I've sent a request to that group and I'll see what they say, the company that did the regrind certainly seemed to know their stuff so hopefully I'm just being paranoid.

[itchyfeet]

the company that did the regrind certainly seemed to know their stuff

Who did the regrind?

Always good to be sceptical, it's what good engineering is all about IMO.

[freckvan1]

the company that did the regrind certainly seemed to know their stuff

Who did the regrind?

Always good to be sceptical, it's what good engineering is all about IMO.

[bustrucket]

Well it's been a long time without much progress on this! I got the rivets drilled out of the old worn cam(s) and also on the NOS DG cam, unfortunately the +1 size gear was damaged during the process and I had to source another one (many thanks to silverbullet for helping me out there).

Once the gears were all separated I made an attempt at riveting, but this was not very successful. Despite trying various ever more elaborate combinations of punch tools and supports I struggled to get the rivets in anything close to straight, and grinding and punching out the squinty ones was starting to leave the "test" cam & gear pretty chewed up

(by the way, I ended up with a box of 6mm x 16mm rivets and I've still got most of them left, if anyone else needs some, let me know)

I eventually decided it wasn't worth risking it on the NOS cam, and started looking at bolting the gear on instead. Sourced an M7 tap, cut a hole in a bit of plywood and went to town on the poor abused test cam again, it seemed about 10x easier than the riveting! I did discover that tapping by eye wasn't going to be accurate enough though, I got 3/4 of them straight but screwed up (lol) the last. Agonised over the best way to avoid this happening again, the solution ended up being pretty simple - I drilled and faced a bit of brass bar in a lathe and used that as a makeshift tapping block:



I suppose a real tapping block would work better, but of course I didn't have one.

Testing on the scrap cam was fairly encouraging, so I took a chance and repeated the process on the new cam and gear, and (with my a*** making buttonholes) offered the gear up and...everything lined up perfectly! Fitted it into the block and the fit seemed fine, no lash and no sign of it lifting out when the crank was turned backwards Quick test assembly of the case halves and bolts nipped up, everything still turned freely, so I'm fairly happy with that:



Not a lot of space between the oil pump (standard 26mm) and the bolt heads, I had thought I'd try fitting washers but doesn't look like there's room! Might be worth grinding down the bolt heads slightly to increase clearance?



The current bolts are also only 8.8 grade, finding higher grade M7 bolts seems to be difficult, only place I could find was a 2CV specialist - they're 10.9 grade, but they aren't cheap and they need cut down to length. I think I'd rather use the higher grade just for that wee bit extra reassurance though. Here's the link if anyone else needs some: https://www.ecas2cvparts.co.uk/screw-st ... 01ad6cefa9" onclick="window.open(this.href);return false;

And in among all that, I also reamed out the pistons as the gudgeon pins were a tight fit, they needed tapped out and I'd never have got them back in by hand. I suspect there were some slight burrs on the circlip grooves. Anyway the pins are a lot smoother fit on the pistons now.



Still loads to do, but some progress is better than none lol. Hopefully it wont be another 4 months before the next update...