Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

[kevtherev]

The only thing you have to do is change the water pump and thermostat housing to fit the oil cooler hose.

Kev

Excuse me quoting you from a different thread, but I thought this question would just clutter up Simon's thread. Do you know if there is a diagram of the way the oil cooler is plumbed into the newer cooling system? Since I'm planning to retain my older cooling system I doubt there'll be a 'standard' solution, but if I know which part of the circuit it connects up to in the new system I can try and do something similar.

The thermostat housing on a DJ has an extra spigot, it runs a pipe over the top of the block, from there to the oil filter sandwich plate sitting under the spin on filter, from there it routes very tightly to the water pump which has and extra spigot, the pump literally sucks coolant through the plate.
I bought used pipe work to connect the various components, though I believe you can buy it new now.
The thermostat housing was from BY as was the pump

[kevtherev]

http://www.brickwerks.co.uk/index.php/t ... -hsng.html" onclick="window.open(this.href);return false;

http://www.brickwerks.co.uk/index.php/t ... ooler.html" onclick="window.open(this.href);return false;

[CJH]

Thanks Kev. Is yours the later cooling system? I imagine I might have to install some T-pieces and rubber hose to replicate that arrangement on my older cooling system. I don't want to risk creating a short cut for the coolant such that it no longer reaches the rest of the circuit though, so I think I need to study the routing on the newer system. Actually I've just remembered I've got the thermostat housing and the water pump that came with the MV, so I should be able figure out what I need to copy. I'll have a browse through Bentley to see which spigot is which.

I had originally planned to update the cooling system at the same time as fitting the new engine, but since my cooling system works well and I've got a spare of the main hard-to-find part (the thermostat housing), and a new water pump waiting to go on, I'm going to stick with my older system.

[CJH]

Looking at the later type thermostat housing and pump that were on my MV when I bought it, it looks like the oil cooler only gets water when the thermostat opens (makes sense), and therefore the water it's getting is from the cooled return from the radiator. The water that leaves the oil cooler rejoins the circuit at the pump, as pointed out by Kev.

So how to achieve this in the older cooling system, given that the pump and the thermostat housing won't have the necessary spigots?

I found this rather handy schematic of the early cooling system in the Bentley manual.



One issue is that the connection between the thermostat and the pump is not a pipe, as it is on the later system - the thermostat housing butts up to the pump (the part I've marked with the red arrow above), so it's not possible to feed the return from the oil cooler back into the pump input.

I can't immediately see an alternative other than to add a circuit into the radiator return, as I've marked on the figure. Apart from the difficulty of splicing into this pipe, my main concern is how to make sure that the water would circulate through the oil cooler - why wouldn't it just take the easy route and bypass the cooler? I suppose I could break the existing pipe altogether, so that all the water returning from the radiator has to go round the oil cooler, but then I'd need to make sure that I could get enough flow rate through the cooler.

Actually, looking again at the diagram above, maybe the pipework for the automatic transmission cooler would do the trick. If I could get a pair of the fat pipes for an early cooling system with automatic transmission I could run some ordinary rubber hose from those unions to the oil cooler. Yes, I'm sure those pipes won't be scarce at all.....

[CJH]

How much?!!

And I'd need two!

[kevtherev]

How much?!!

And I'd need two!

My pal shep fitted a DJ into an early cooling system, I don't think he bothered with it....several years later it has never been an issue.
If you really want to fit a cooler then do it right with a Mocal thermostatic sandwich plate under the filter, coupled with a 9 row heat exchanger/radiator.

[CJH]

My pal shep fitted a DJ into an early cooling system, I don't think he bothered with it....several years later it has never been an issue.
If you really want to fit a cooler then do it right with a Mocal thermostatic sandwich plate under the filter, coupled with a 9 row heat exchanger/radiator.

Thanks Kev. Shep's advice early in this thread was to try and plumb the cooler in, so I hadn't realised he hadn't bothered. I've seen that thread on using 20W50 to counter low oil pressures, so it crossed my mind that I might go that route instead, and fit oil temp and pressure gauges to keep an eye on things.

The Mocal sandwich plate+radiator though, assuming that's oil-to-air, seems like a better idea than cutting into my cooling pipes and adding more potential leaks! Where do people usually mount the radiator?

[CJH]

I've just noticed Silverbullet's 'Edna' thread, and his MV pistons (1st picture) don't look the same as the ones in mine (2nd and 3rd picture), which I thought were MV. Can anybody confirm for sure what my pistons are?

Silverbullet's:

Mine:

[kevtherev]

The Mocal sandwich plate+radiator though, assuming that's oil-to-air, seems like a better idea than cutting into my cooling pipes and adding more potential leaks! Where do people usually mount the radiator?

in the wind tunnel side vent

[CJH]

in the wind tunnel side vent

Ah, that makes sense - in a good air flow and tucked out of the way to avoid damage. Thanks Kev.

[CJH]

Can anybody confirm for sure what my pistons are?

Well I'm confused now, but relatively happy I think. As far as I can see from browsing round various forum posts, my pistons are actually DJ pistons after all. This post on VolksHub contains these photos with MV and DJ pistons side by side. While the post doesn't actually say which is which, the ones with the deeper dish have to be the MV pistons don't they? They certainly look like Silverbullet's 'Edna' MV pistons. Which makes mine, with the dimples in the centre, DJ pistons after all.




I based my original assumption on this image from that WBX page. But as you can see from the photos of the two piston types, the measurement 'a' clearly doesn't differ by 6.3mm (15.5mm - 9.2mm) - in fact the two measurements look very similar. Maybe I'm interpreting the figure wrongly?

[ajsimmo]

Look again at the piston diagram on the WBX page - dimension "a" refers to the dish depth of the piston, not the height of the second ring groove. The reference line through the cross section just happens to go through there!
You do have dj pistons.

[CJH]

Look again at the piston diagram on the WBX page - dimension "a" refers to the dish depth of the piston, not the height of the second ring groove. The reference line through the cross section just happens to go through there!
You do have dj pistons.

So it does - I was misinterpreting it. Thanks Andy. So I can save my money for the time being. Somehow I already feel quids in.

[CJH]

Right - the next thing I'd like to check. Distributor. Will I get away with my DG distributor on a DJ?

From the Brick-yard technical data pages the timing data is slightly different. But is it close enough to work properly, or should I look out for a proper DJ distributor?

DJ

distributor part number: Bosch - 0 237 022 054
ignition timing: 10°±1° BTDC @ 800RPM without vacuum see note.
Ignition advance checks: 0°-2° @ 1050RPM w/o vacuum and basic timing
2°-6° @ 1300RPM w/o vacuum and basic timing
12°-16° @2400RPM w/o vacuum and basic timing
vacuum advance range: 12°-16° engine degrees (9-11)

DG

distributor part number:Bosch - 0 237 024 011 (0 237 024 035 - 1985-1992)
ignition timing: 5°±1° BTDC without vacuum see note at bottom of page
ignition advance checks: 0°-2° @ 1500RPM w/o vacuum and basic timing (0-1 @1160)
10°-14° @ 2400RPM w/o vacuum and basic timing (13-17 @2400)
24°-28° @4200RPM w/o vacuum and basic timing (24-28 @4200)
vacuum advance range: 12°-16° engine degrees

[kevtherev]

I used the DJ distributor, as did shepster.