1Y 1.9 diesel into '74 bay

[Superleggo]

Trev

If you heat the ends of your blue pipe over a gas stove then they self form into nice flanges. Should save them popping off

[trev]

Genius! Will do

[trev]

after superleggo's tip above, I did just that and flared the ends of the pipes nicely. I also re-routed one of the blue pipes over the rear torsion tube to give it a straighter shot at the radiator. In doing so, I eliminated a hump in the waterflow from engine to radiator and a possible air-locking point.

Now that it's driving and I'm sorting out the niggles, I haven't actually driven it more than a few miles in any one go. The reason being that it heats up to maxing out the gauge in the space of two miles or so which troubles me. The radiator is getting hot all over so isn't air locked, there are no potential air lock points within the system. The fan has only cut in once, the switch is rated at 95 degrees. Should I be concerned about this? Should I brave-up and go for a longer drive? The gauge is a standard VW/VDO 120 degree item from a mk1 Golf and the sender on the engine a four-pin 1Y sender which I'm using one of the signal pins. I think it's a yellow sender, I know they come in different colours.

Is there maybe a discrepancy between the sender and the gauge?

[trev]

I pulled the 1Y coolant temp sensor (4-pin, green band) and put in one I kept from a B3 Passat I broke a while back (2-pin, blue top) and the coolant gauge is now reading nicely! Turns out the green one was 0-140 degrees, the gauge is a 0-120 degree gauge and the blue sender is 0-125 degrees. The blue sender and the gauge work much better together, thankfully

Next job is to box off the sides of the radiator to ensure any air that piles up above it goes through it, not around. There's also a weep of oil from the cam cover that needs to be sorted.

It's driving nicely though. However, even with the 2-litre 6-rib gearbox, it really would benefit from a fifth gear. Upside-down passat box might be the way to go.

[splitbusvanatic]

Great news Trev.
I'm slap bang in the middle of the flipped Passat box conversion at the minute.
Albeit with an AFN engine and its 'box.

I have my own steel 15mm adapter plate bolted to the engine right now.
Just to bolt on gear box when i get 15mm removed off it.
I'll update my own thread as soon as I have a few pics together.

You should suffer on with the aap for a while and make sure everything is ok.

Then make the switch.

Dan.

[trev]

when you get to the shift mechanism make sure you post some details Dan! I can visualise mounting the thing upside down etc but the shifting of it is hard to see.

I've been putting up a few miles on the bus driving locally etc and with no scoop/ducting on the rad, the needle is sitting just under the red zone on the end of the gauge. On a good hill nearby it rises into the red zone and the fan kicks in.

Last night I started on the ducting, it's made from 1mm galvanised steel, folded up on a small folder I have in the garage. The next part is the bit behind the radiator. I'm hoping to induce a low-pressure zone behind the radiator to help draw the air out. I plan to put a slight flare on the front end of the duct to grab a bit more air than just the duct itself. The idea is to protect the radiator from debris kicked up from the front wheels while funnelling air to it and diffusing air away from it.

[trev]

got the rear part of the duct made tonight. It was a bit of work drawing it all out and then working out the flat pattern to be transferred to the sheet before folding as it gets wider and deeper towards the rear. As I mentioned above, the idea is to create a low-pressure zone behind the radiator to help draw the air through it. The fact that it gets wider and deeper than the rest of the duct will lower the pressure but as an extra help, I folded a 1" lip around the trailing edge to further upset the airflow around the outside of the duct and lower the pressure inside it even more.





I'm no aerodynamicist, these are all my tin-pot estimations. The proof will be when I drive it again, whether the needle reads lower and whether the fan cuts in up that big hill near me.

the bungee-cord prototyping system is useful for keeping everything loosely in place while I build it up, once I've made that last closing piece in the middle and sealed the sides of the radiator inside the duct, I should be good to go. Oh, the chassis rails will have to be sealed up to the underside of the floor to stop the air spilling out the top too.

As for ground clearance, I still have 7.5" below the front flat part of the duct and 6" below the lip on the very back of the rear part. I know it seems low for a bus but the sump on my mk1 Golf is 2" from the ground and I haven't caught anything yet (fingers crossed!).

[trev]

well I'm glad to report my fag-packet fluid dynamics experiment is a success!! I finished the ducting tonight and took it for a "spirited" 20 mile jaunt including up and down that big hill near me in both directions. The temperature needle sits just below the halfway mark for flat driving at 90kph and rose to just over halfway towards the top of the hill while maintaining the same speed. Result!!

There is a small bit of fluttering noise from the leading edge of the duct but a fold along the edge will stiffen it up and remove the flutter. A small modification thankfully. I'm really thrilled it's working as it was all very "seat of the pants" engineering.

here are some pics for reference:











the lowest point on the duct is the lip on the rearmost section, it's 5.5" off the ground. The main part of the duct is 7.5" clear. Part of my drive was over a set of speedhumps. No scraping!

one thing I did notice due to my "spirited" drive was that the clutch will slip between 2nd and 3rd or 3rd and 4th if I get on the throttle too soon. The clutch kit is the standard 1800 air-cooled type and is no more than 2000 miles old. Evidently it's too small for the torque of the diesel engine. I'll have to research a solution and just take it easy in the meantime.

[splitbusvanatic]

Nice one Trev.
Sexy bit of fabrication there.

Re: the clutch slip.
I am gettin the same feeling of clutch slip on my test drives.
I have the 1.6d mated to its own diesel gearbox though.
Only difference being I converted the clutch from hydraulic to cable.
May have been a mistake.

I suppose my point is. Was your Diesel engine operated by a hydraulic
operated or cable operated clutch. ?
Might be why it's slipping now that's it's mated to a cable pedal 'box.

Or if it was cable operated.
Do you need to adjust your Clutch Bowden tube or wing nut. ?


Or I could be talking out my A-hole and making more work for you.

[trev]

2 months on, including 6 weeks of daily driving and the old dear hasn't missed a beat! It hasn't overheated once, the fan has come on only a handful of times in the 2 months.
It's still leaking a drop of oil out of the rocker cover and the wiring needs to be taped up but I'll do those finish-up jobs over the winter.

I'm still considering the 5-speed conversion but I've spoken to a chap here who went from 2-litre box to upside-down 5-speed and he basically had to re-engineer EVERYTHING to get it working. His engine ended up lower so he had to remake all the engine mounts, pipes, hoses etc.

[69Bay]

Been reading through your post and really like what you've done, glad to hear everything's going well.

Just about to start out on my conversion 1z engine + passat box (see my post). Your thread is one I have followed closely to convince me that diesel is the way forward

Out of interest who else on here has used the upside down passat box? I have seen splitbusvantastic's thread.
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1969 Baywindow - soon to be TDI