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1.6 diesel to 1.8 8v carb conversion help needed

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Hi, my first post here so please be patient with me…

I have a 1.6 diesel Caddy pick-up with a blown head gasket. I want to convert it to petrol but want to keep things as simple as possible. I have bought a good Mk2 1.8 8v petrol engine and have also just bought a webber DMTL 32/34 carb for it.

I have found lots of info on more complex swaps but can't find much on this swap. I understand that I can use the existing fuel tank and line, engine mounts (I have the Mk2 ones as well if I need them), the only thing I seem to have any problem with is finding any info in the wiring from Diesel to carbed petrol. Does anybody here know what's required and if I can use the existing loom/fuse box and just add to it?

Any help would be much appreciated

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Welcome along mate.

An unusual changeover as most would go for a later turbo diesel conversion.

What would be useful is if you can find the engine loom for the 1.8 and then plug it into the engine loom port of the fuse box.

Otherwise it's a case of installing wire by wire probably.

I'm sure rubjonny will be along shortly as he's the wiring expert.

Ian

Cornish Host.
1980 VW Derby
Clive the Cabby
Ujum the Invisible
Mynx the  Tintop

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i have a harness removed from 1990
clipper

Do not know a lot but willing to help if possible

1989 Sapphire Blue Mk1 Cabriolet KR
1985 Atlas Grey Mk2 GTI 2.0 ABF

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borednow said

Welcome along mate.

An unusual changeover as most would go for a later turbo diesel conversion.

What would be useful is if you can find the engine loom for the 1.8 and then plug it into the engine loom port of the fuse box.

Otherwise it's a case of installing wire by wire probably.

I'm sure rubjonny will be along shortly as he's the wiring expert.

Ian

Thanks for the welcome

I wanted to keep things low cost and straight forward and prefer the simplicity of a normally aspirated petrol motor with a carb. This car was not supposed to turn into a project, I still need to finish my 1868 Fiat 500 with the 18 bhp air-cooled motor junked in favour of a 140 bhp water cooled 4 cylinder, as well as a number of motorcycle projects that I have on the go. I thought the 1.8 8v which in standard form puts out roughly double the power of the 1.6D will do the job for now.

It's useful to know that the engine loom is swappable just by plugging into the back of the fuse box. I was hoping that there would only be a few wires difference between the n/a diesel and the 1.8 carbed petrol but a plug in loom sounds pretty easy.

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nicci21paul said

i have a harness removed from 1990
clipper

Interesting, how much are you looking at for the loom?

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A lot of the wires will be the same.
headlights, alternator, starter, fan I guess you will need to add things like coil, Rev counter, ignition system etc.

If the original fuel tank looks old and crusty then best swop it for new as they do rust out from the inside if sat around with little fuel in the tank unused, at least have a good look inside.

1988 Mk1 Golf GTi Cabriolet 1.8cc DX, K-jet. Daily drive. 317,000 miles and counting
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.

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you could keep the old loom if you wanted, most of it will just plug in.

for rev counter you'll need to run the red/black on the 2 pin spade plug over to your coil for the rev counter, plus run an ignition live to power it from the fusebox.

if its a weber carb you'll just need to find another ignition live for the carb heater if its got one and tape up all the spare wires left over from the diesel lump. might need to add a 2 pin plug for dash temp sensor if its from a later car, splice 1 pin to the old yellow/red wire and 2nd pin is earth

Hello my name is John and I'm a dub addict.



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19805F49-19CB-4904-A70B-B859EA617076.jpeg It turns out that the engine I bought is a 1.6 not 1.8 (late engine so uses the 1.8 block but EZ engine code) I'm a bit annoyed but it's in very good shape and it's better than a motor with a blown head gasket! I'm probably going to do a more extreme swap at a later date but I just need to get it on the road for now.

I have an aftermarket Webber DMTL carb for it but I have a question. The inlet manifold has a set of pins cast inside the inlet tract. What are these for? I'm guessing that they create turbulence in the combustion gasses but do they work or should I consider grinding them out?

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Hudsonhenry said

19805F49-19CB-4904-A70B-B859EA617076.jpeg It turns out that the engine I bought is a 1.6 not 1.8 (late engine so uses the 1.8 block but EZ engine code) I'm a bit annoyed but it's in very good shape and it's better than a motor with a blown head gasket! I'm probably going to do a more extreme swap at a later date but I just need to get it on the road for now.

I have an aftermarket Webber DMTL carb for it but I have a question. The inlet manifold has a set of pins cast inside the inlet tract. What are these for? I'm guessing that they create turbulence in the combustion gasses but do they work or should I consider grinding them out?

'hedgehog', electrically heated element to stop 'icing' in the colder damp months (ie about 3/4 of the months in the UK). Find a 1.9D from a MK3 Golf and install that instead of a petrol.

1983 Mars Red 1.8 Golf GTI
1987 Alpine White 1.8 Clipper Cabriolet

The trouble with doing nothing is that you never know when you are finished.

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1.6 diesel to 1.8 8v carb conversion help needed

I kept the manifold as is and put a 32/34dtml on mine with the rubber flange and it runs great

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yeah its inlet heater and also helps with swirl apparently. fair few guys grind the pins off but I wouldn't bother with that just fit and go.

You probably wont see any issues without wiring it up, the heater turns off once the coolant has heated up a bit anyway. if you do decide you need it then you need to wire up a relay for it linked to the red thermoswitch round the front.

factory you have a #1 relay fitted in slot 2 where the old glowplug relay is. you can re-use the old glowplug wire crimp a spade on it and plug to the heater then find the wire from the diesel temp sensor to d/13 and wire that to one pin on the red switch, give the other pin ignition live.

Hello my name is John and I'm a dub addict.



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Thanks for all of your help guys, New engine is now back in the car and I'm trying to sort out the wiring which is where I'm coming slightly un-stuck! Your help anginas would be very much appreciated

I have a 1.6 EZ 8V engine from a MK2 and an engine loom from a Clipper.

The engine arrived with the oil pressure and temperature sensors missing so I asked VW Heritage which ones I need but apparently their system doesn't know which engines came with which sensors so they can only go on what colour is already fitted to the engine. Does anybody out there have an EZ 1600 motor (MK2 golf that could look and tell me which colour sensors I need and if there a two or three.

The part of the loom that runs don the middle if the engine bay is the original diesel and still has the pre heater wire which I assume I can remove. On the right hand side below the brake fluid reservoir there is a twin connector on both sides but the Clipper loom has neither of these, what are they for and do I need to wire them in? I do have a connector on the clipper loom that is quite close which has a yellow/white wire and a brown wire, what does that connect to?

IMG_6001.jpg

I am missing a sensor on the right of the head which I think is either oil tea or oil pressure and below that on the water pipe bit is another sensor which I'm guessing is water temp for the gauge. What colour wires should connect to these sensors?

IMG_6007.jpg

Moving round there is a hole for a sensor on top of the oil filter housing which I think should be the low oil pressure sensor with a blue/black wire that looks like its in the right place and the to the left of that there is a pair of sensors above and below the outlet that goes to the radiator. I have two connectors (wrong type for the sensors but I don't know what either of these do and which should connect to which

IMG_6008.jpg

IMG_6009.jpg

IMG_5999.jpg


Moving inside to the fuse box there is a branch off the main loom connector with a red/black and red/yellow connector branching off which in turn has a single red/black wire and connector, what are these for and where do they plug in?

IMG_5981.jpg
 

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The side of the head is where the LOW Oil Pressure switch was located on my Diesel, it was notorious for leaking oil and I usually replaced it every 40K miles over the 20 years of Dieseling.  

I don't think that you could use the Standard "CAN" dual ported Switch/Pressure sender as the ones fitted for the  1.8 isn't rated high enough for the pressure as the standard is 5 bar, and IIRC the running pressure in a Diesel is closer to 7 bar.  I think that you would blow the can sender up.  Not saying that they don't make a pressure sender for Diesels I just don't know of one off the top of my head.

The ones on the flange are  black single pin for the Oil Temp, and the other for the Low pressure at High RPM, but then too I don't know the rating or the color of that sender.

The sender on the water outlet flange should be for coolant temp sensor and the CTS sender that should tell the ECU on a Cabbie what the engine is doing  usually in the outlet flange in 85-89 cabbies it was a single pin black sender similar to the oil temp sender on the oil filter flange to move your gauge in the car.  It should be the yellow/red with the brown wire connector for the water temp gauge in the clocks.

The Blue/black Capped one is the low pressure/Hi rpm sensor wire.  

I suspect that RubJohnny is going to have the definitive answer for all the above and the others that I have missed ..


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Thanks for the reply, Sorry, probably wasn't clear in my post, I have removed the broken diesel engine and replaced it with a 1600 petrol engine from MK2 golf (EZ) - I got hold of a MK1 clipper engine loom so I now have part clipper petrol loom on the right hand side of the bay and part original Diesel (running down the middle).


Briano1234 said

The side of the head is where the LOW Oil Pressure switch was located on my Diesel, it was notorious for leaking oil and I usually replaced it every 40K miles over the 20 years of Dieseling.  

I don't think that you could use the Standard "CAN" dual ported Switch/Pressure sender as the ones fitted for the  1.8 isn't rated high enough for the pressure as the standard is 5 bar, and IIRC the running pressure in a Diesel is closer to 7 bar.  I think that you would blow the can sender up.  Not saying that they don't make a pressure sender for Diesels I just don't know of one off the top of my head.

The ones on the flange are  black single pin for the Oil Temp, and the other for the Low pressure at High RPM, but then too I don't know the rating or the color of that sender.

The sender on the water outlet flange should be for coolant temp sensor and the CTS sender that should tell the ECU on a Cabbie what the engine is doing  usually in the outlet flange in 85-89 cabbies it was a single pin black sender similar to the oil temp sender on the oil filter flange to move your gauge in the car.  It should be the yellow/red with the brown wire connector for the water temp gauge in the clocks.

The Blue/black Capped one is the low pressure/Hi rpm sensor wire.  

I suspect that RubJohnny is going to have the definitive answer for all the above and the others that I have missed ..


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any remai9ning diesel wiring can go yup, wont need any of it.

yellow/white and brown 2 pin is for front fog lights. the switches on the master cylinder are for the brake lights, dig the wiring out of the old headlight loom or it might be a separate loom that goes through the bulkhead on its own depending on age of car

oil switches you should have a 0.25 or 0.3 bar switch in the side of the head, blue or brown in colour. filter housing its 1.8 bar white.

sensors in the front flange are thermoswitches for autochoke heater (white) and inlet manifold heater (red) if you have a weber the white one isnt used.

on clipper loom the red/yellow and brown 2 pin plug is dash temp, cut the plug off and pull it over to the single spade sensor in the side of the head. the other 2 pin plug doesnt look right for a carb, what engine was it from?  The inlet thermoswitch would be black and purple/black with a red plug, and carb heater would be yellow/black and black with a white plug…

yellow/red and red/black is fusebox plug for brake light switch wiring I mentioned earlier, so find the original wiring for it or make one if not its only 2 wires, simples

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i will get the engine code
tonight

Do not know a lot but willing to help if possible

1989 Sapphire Blue Mk1 Cabriolet KR
1985 Atlas Grey Mk2 GTI 2.0 ABF

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Thanks for the info, its very usefull

This part of the loom is from the original diesel ie the blue/white oil pressure sensor, the blue white and brown  with the connector, the yellow red, brown with the connector and the red(file cut off?) I don't have black and purple/black wires, can I get away without a carb heater?

IMG_5999.jpg

rubjonny said


on clipper loom the red/yellow and brown 2 pin plug is dash temp, cut the plug off and pull it over to the single spade sensor in the side of the head. the other 2 pin plug doesnt look right for a carb, what engine was it from?  The inlet thermoswitch would be black and purple/black with a red plug, and carb heater would be yellow/black and black with a white plug…

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ok so what wiring have you got from the clipper then?

white/blue and brown will be for the diesel temp sensor for glowplug relay I guess.

you only need the carb heater for a 2e2 type carb, if its had a weber then no need to worry about that. The inlet heater is still there though, but you may find it makes no odds without. If you do need it check the blue/white from the sensor, if it goes to D/13 on the fusebox then you can use it for the red thermoswitch, pop a spade on it. then you put ignition live to the other pin, fit a inlet heater relay #1 to slot 2 and run the inlet heater to spade N (can re-use the glowplug wire)

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I seem to have ended up only with the right hand side of the clipper loom that does the front lights, indicators, alternator etc. It seems I'm missing the separate bit that runs down the middle and does the carb heater oil switches and so on.

rubjonny said

ok so what wiring have you got from the clipper then?

white/blue and brown will be for the diesel temp sensor for glowplug relay I guess.

you only need the carb heater for a 2e2 type carb, if its had a weber then no need to worry about that. The inlet heater is still there though, but you may find it makes no odds without. If you do need it check the blue/white from the sensor, if it goes to D/13 on the fusebox then you can use it for the red thermoswitch, pop a spade on it. then you put ignition live to the other pin, fit a inlet heater relay #1 to slot 2 and run the inlet heater to spade N (can re-use the glowplug wire)

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ah ok that makes sense then, you just have the headlight loom which doesnt really help with the engine side of things

the diesel loom is fine just needs a couple tweaks mainly to add coil power and rev counter to coil if you want it, plus sensor stuff above

Hello my name is John and I'm a dub addict.



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