Heads Off Due To Pressurised Coolant

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maxstu
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Re: Heads Off Due To Pressurised Coolant

Post by maxstu »

937carrera wrote:
28 Jul 2020, 20:09
https://club8090.co.uk/forum/viewtopic.php?f=37&t=164888

Second post... nice pictures of DG pistons too

The stamp is I think because it has been rebuilt by VW at some point....... buy mine has no engine number so either mine was rebuilt with fresh cases (which have no number), or at some point the policy was to remove the engine number. Someone has been a bit naughty with the code haven't they

Are you just doing a top end on this, i.e not splitting the cases ?


Not splitting cases. This is a standby engine in case my "real" DJ 2.1 starts leaking further.
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maxstu
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Re: Heads Off Due To Pressurised Coolant

Post by maxstu »

Cobra88 wrote:
28 Jul 2020, 20:18
The metal bit looks like part of a thermostat to me

Good call Rick :ok l have the thermostat housing in a crate somewhere. Will take a look.
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Re: Heads Off Due To Pressurised Coolant

Post by maxstu »

silverbullet wrote:
28 Jul 2020, 17:36
FWIW, those are DG pistons and you cannot team them up with a 76mm crank, because at TDC the crowns will pop out the top of the barrels!

Its a DG. If you want a 76mm crank, I have a few ripe for regrinding. Might have a set of good used DJ pistons under the bench, need to have a clear-out.
Had a bit of a sleepless night thinking about this. Whats involved?
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Re: Heads Off Due To Pressurised Coolant

Post by silverbullet »

If you are rebuilding, the minimum spec should include new con rods (cheaps as chips and still available, unlike the rod bolts that are NLA and a PITA to change anyway) and a set of rings for the pistons.
Rods are all the same length (137mm between centres)
2.1 cams are also NLA and the DG one is feeble, I have some new 2.1 ones that need "dialling in", easier for me to match them to the customer's old cam gear on my fixture than expect them to do it DIY (the 4 rivets aren't that accurately drilled on the OEM cams)
I could have sworn that I was getting out of the wbx game but it's just so much fun :lol:

A DJ wearing DG clothes should get you a good 90 bhp and 170Nm with a decent exhaust, not far off an MV but a lot more punch thanks to the 10:1 compression ratio
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Re: Heads Off Due To Pressurised Coolant

Post by maxstu »

Oh! :shock: l think l need to read this info about three times over.
Regards
Stuart
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937carrera
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Re: Heads Off Due To Pressurised Coolant

Post by 937carrera »

There's a reason why I asked if you were intending to split the case :wink:

Here's something else for your dreams.

https://club8090.co.uk/forum/viewtopic.php?f=37&t=164160

I just added the DJ power curve for ease of reference.

Some warnings:

The power output of the DJ is in part achieved by the cam and fuel injection. Running on carbs will not get you to the same power levels, and power is a mathematical calculation from torque.

To go to 2.1 you will need crank, pistons, mains, big ends as an absolute minimum, plus a bit of clearancing (Ian says rods as well).

You will need a good puller, and probably heat to remove / replace the dizzy drive to do one of the mains

Flywheel off and adjust the crank end float (you should probably do this regardless)

If you go to the 2.1 cam that'll cost money, use the DG one and output will probably be compromised..... but it may be more torquey

You'll probably have to make some jet adjustments to the carb, not difficult, but who knows what they are

After that there's no real difference in the rebuild, except you have a 2.1 instead of a 1.9

I have no idea if the 90hp is a good number or not, but similarly have no reason to challenge it. My DF/DG hybrid gives around 70HP, 10 more than a DF due to the DG heads, 8 less than a DG because of the DF cam...... but it only loses out on performance at the very top end because the cam gives low down torque.

I just did a simulation assuming your hybrid produces 53kW at 3500 rpm (80% of a DJ similar to the 90/112). The answer is 145Nm, looking at the graph a DG would be giving 138Nm

More money, better result, not a lot of additional effort

Sleep well :)
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
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Re: Heads Off Due To Pressurised Coolant

Post by maxstu »

Interesting reading, indeed! And many thanks to both for answering my posts.

This started out as purely a top end rebuild for a spare engine as its been sitting in my garage for over a year. I did fit this engine to a previous camper and it ran well for about six months. Then started pressurising the cooling system. Then another DG became available from a fellow club member (Steve in Gravesend). Now that was a peach of an engine. Sold that camper six months later to concentrate, with newly gained funds, on my Auto DJ 2.1

The DJ has beeen reliable for over a year now. But l noticed after a recent 1000 mile tour towing a small folding caravan that both jackets are slightly weeping. A pink discolouring has appeared on top of both water jackets. So there's a failure lurking.

So the DG can stay as it is with new rings and seals ( and correctly set end float) and act as a temporary workhorse while l do the heads on the DJ later this year or early next.

Unless lm missing something obvious, there no reason not to use a DG, or as lve now named it, a JG, with auto and Digijet?

Regards
Stuart
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Re: Heads Off Due To Pressurised Coolant

Post by 937carrera »

Ah, missed that bit, well I didn't but the cogs were not whirring properly: you already have a DJ

Putting a 1.9 engine where the metering unit is expecting a 2.1 could throw the fuelling off.

I think it behaves as an airmass meter, so the fuel quantity delivered should still be OK, but I'm not 100%. Need to get my head around it more.

Sheep number 1, sheep number 2, sheep number 4, sheee.....zzzzzz

Have you thought about nipping up the head bots on the 2.1 ?
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

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maxstu
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Re: Heads Off Due To Pressurised Coolant

Post by maxstu »

937carrera wrote:
29 Jul 2020, 21:15
Ah, missed that bit, well I didn't but the cogs were not whirring properly: you already have a DJ

Putting a 1.9 engine where the metering unit is expecting a 2.1 could throw the fuelling off.

I think it behaves as an airmass meter, so the fuel quantity delivered should still be OK, but I'm not 100%. Need to get my head around it more.
was hoping it would not affect running. Or at least self adjust

Sheep number 1, sheep number 2, sheep number 4, sheee.....zzzzzz

Have you thought about nipping up the head bots on the 2.1 ?

Yes. But the seals look pretty ragged anyway. And only when the JG is ready. Besides the current rebuild is giving me confidence to remove the 2.1 and tackle that issue.
Maxstu
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937carrera
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Re: Heads Off Due To Pressurised Coolant

Post by 937carrera »

I think what you would be doing is making a GW engine

http://vwt3.com/t3-tech/t3-data/engine-data/engine-data-vw-t3-1-9l-gw/

Looking in ETKA the air metering unit for a GW is different to a DJ (suffix A vs C), but the DH engine is the same part as the DJ. Maybe that's just a difference to manage the idle speed (less air needed on a 1.9 for idle)

Have a read here too https://club8090.co.uk/forum/viewtopic.php?p=8198632

DG and GW share the same camshaft I believe
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

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Re: Heads Off Due To Pressurised Coolant

Post by ajsimmo »

A tad of over-thinking going on here, perhaps? I have a 2.1 DJ auto pick-up, and have put several different engines in it for testing or running-in purposes. The DJ, MV & DG have all run perfectly on digijet and/or LPG. The DG went so well on injection it was almost as good as the MV.
So the upshot is the DG will serve perfectly fine as your stand-in whilst you fix the DJ. No more sleepless nights

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maxstu
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Re: Heads Off Due To Pressurised Coolant

Post by maxstu »

Aha! The kind response l understand :ok
Thanks Andrew. Think l will have a snooze now.
Regards
Stuart
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937carrera
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Re: Heads Off Due To Pressurised Coolant

Post by 937carrera »

ajsimmo wrote:
30 Jul 2020, 11:04
The DG went so well on injection it was almost as good as the MV

Ah, wonderful, the welcome voice of empirical experience

:ok
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

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Re: Heads Off Due To Pressurised Coolant

Post by silverbullet »

Wasn't there a carb'd 2.1 for certain markets (France?) Something like SP code?
85 syncro Caravelle twin slider Oettinger T3200E-6
90 SA Microbus supercharged wbx/UN1 project

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Re: Heads Off Due To Pressurised Coolant

Post by maxstu »

silverbullet wrote:
30 Jul 2020, 18:01
Wasn't there a carb'd 2.1 for certain markets (France?) Something like SP code?
No idea! But getting fecked off cleaning and cleaning and cleaning. :evil:
Maxstu
1989 DJ 2.1 Auto Leisuredrive rusty bucket.
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