Old school VW diesel into 86 Scirocco?

cujet

Veteran Member
Joined
Jun 5, 2005
Location
Florida, Hurricane central
TDI
2006 Jetta
I have 2 diesel rabbits. A neighbor has a fairly nice 86 Scirocco that could easily accept the diesel, with plenty of room for a home made turbo!

What do you think?

Chris
 

3baudios

Veteran Member
Joined
Mar 20, 2008
Location
winston NC
TDI
93 eurovan AHU (almost), 88Fummins, 01 alh golf, 91 toyota alh
I have an 86 scirocco 16v that threw a piston that I am planning on putting a diesel in. For now I'm going to run a 1.6, possibly with a turbo but eventually I want to get a tuned TDI in there.
 

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
La Conner, WA
TDI
... None :S
Remember that the NA diesel motors will not last if you put a turbo on them. If you want a turbodiesel, start with a turbodiesel block :)

-Jason
 

cujet

Veteran Member
Joined
Jun 5, 2005
Location
Florida, Hurricane central
TDI
2006 Jetta
compu_85 said:
Remember that the NA diesel motors will not last if you put a turbo on them. If you want a turbodiesel, start with a turbodiesel block :)

-Jason
Well, OK. Thanks for the info. I was considering putting turbo pistons in and coming up with some form of piston oil squirter. What other differences are there? My thought was not to make it a performance car, but rather more like an Ecodiesel. Gear it tall and run 5 pounds of boost to achieve clean running and no significant smoke. Maybe a few more HP just to get the car to cruise on the highway comfortably.

Chris
 

cujet

Veteran Member
Joined
Jun 5, 2005
Location
Florida, Hurricane central
TDI
2006 Jetta
You will have to excuse my general lack of knowledge on the various VW diesel engines. I am not 100% clear on the various engines and what they came in/what they fit.

You can understand my reason for using the MK1 rabbit diesel engine in it. I have 2 of them. It would be an easy swap, even with a custom turbo system.

Later model engines? What do you suggest? Maybe I can sell what I have and purchase a better engine. Please be specific so I don't misunderstand you.

BTW, check out www.cujet.com and go to the "other projects" page to see what I build. This is well within my capabilities.

Chris
 

GoFaster

Moderator at Large
Joined
Jun 16, 1999
Location
Brampton, Ontario, Canada
TDI
2006 Jetta TDI
Jeez, nice work there! You will not have trouble with this project.

If you already have a spare Mk1 Rabbit diesel engine and gearbox, it will go straight into that Scirocco, since all Sciroccos are Mk1 cars. Dead simple, you won't even have to think. 'Course, that engine will be complete with all rompin stompin 48 horsepower unless you do something to it.

The VW turbodiesel engines have internal differences compared to the earlier non-turbo diesels. For one thing, all the turbodiesels have oil-squirter jets for the bottom of the pistons. Some other internal parts were strengthened but I don't know the details of this. Everyone says that if you want your turbodiesel to live, you should start with a turbodiesel long block, not a regular normally-asthmatic one. It is possible that the later 1.6 normally-asthmatic engines got some (? not sure) of the upgrades on the turbo engines but again, I don't know the details. Someone on www.vwdiesel.net will know the answer to this for sure, though.

The 1.6 turbodiesels '84(?) - '92 will drop directly in place of the 1.6 regular diesels with the usual minor intake and exhaust fiddling. If the engine came from a Mk2 ('85 - '92 in North America) it will need some engine mount fiddling and possibly accessory-drive fiddling to get it into a Mk1 (i.e. Scirocco), but from what I can gather, all the Mk1 engine mounts and accessory parts will go straight on no problem.

Next up is a 1.9 turbodiesel, engine code AAZ, from Canada, 75 hp in stock form, can be tweaked to 90-ish. These came in Mk3 cars in Canada through to '97 and B4 Passats '93 - '95. They will go into your Rabbit/Scirocco (Mk1) with the usual intake, exhaust, engine mount, and accessory drive fiddling. The bad thing about the AAZ's is that the keyway on the crankshaft that drives the timing belt pulley is weak, and they often get smashed up in 300,000 km give or take, and then the engine goes boom. The 1.6's had the same setup, but with the smaller displacement (and less engine speed fluctuation) it was not a problem. You can substitute a 1Z or AHU (early TDI) crankshaft and timing belt pulley, but if you're going to do that, a different recommendation is below ...

On any of the turbo diesel engines mentioned so far, none of them have intercoolers. You can easily fabricate something so that you have an intercooler and the engine will be much happier for it.

Now, on to the TDI's. If you can get your hands on a 1Z or AHU from a '96 - '97 Passat TDI or a '97 - early '98 Mk3 Jetta, it is the same job to put that into the car as it is to put an AAZ in there, but now you will have to deal with the electronic injector pump. Choice 1, electronic controls - adapt the 1Z/AHU wiring harness and sensors, rig up a throttle pedal position sensor, use the 1Z/AHU ECU, and go all electronic control. Choice 2, fit an injector pump from an earlier turbo diesel and go mechanical. www.vwdiesel.net - the terminology for this that people have adopted is "m-TDI" for mechanical TDI.

Fitting Mk4 or later engines, or VNT turbochargers, gets way more complicated.

So many choices. How fancy do you want to go?
 

alphaseinor

TDI Innovator, Gone but Not Forgotten
Joined
Jul 30, 2006
Location
Denton, TX
TDI
'03 Jetta TDI 780,000 miles (totaled out), 01 Audi TT 225 Quattro 230,000 Miles (runs great!), 00 Cabreetle Beetle dash, ALH & MK4 harness Swap
IIRC Mk4 engines will not have the same mounting points, as for the complexity... everyone's scared of wiring... it's not that hard.
 

cujet

Veteran Member
Joined
Jun 5, 2005
Location
Florida, Hurricane central
TDI
2006 Jetta
Well, as this is an excersize in MPG, a small turbodiesel is OK. This is not a HP project. So, from the power standpoint, the early diesel engines would be OK with just a little boost.

My hope is that the improved aerodynamics of the Scirocco coupled with 20 more HP will enable the car to run at highway speeds without difficulty. The stock diesel Rabbit will do it, as long as there is no headwind. However, it has been windy lately. It is torture to drive the Rabbit in such conditions. Everybody is passing me, and I am smoking like a "pig roaster" (BBQ). While the wind is blowing me all over the road. Not good.

Fabricating piston squirters is no big deal. And turbo pistons are no more expensive.

Chris
 

Lord_Verminaard

Veteran Member
Joined
Jan 23, 2003
Location
Columbus, OH
TDI
2005 NB TDI
I'd say everyone just about covered the bases here. A few things to add though:

You might know it already, but using a N/A injection pump with a turbo will not allow for boost enrichment. This is exactly what the 1.6 "eco-diesel" engines were and it sounds like this is what you are after. The LDA device, which is what the TD pumps have, can be adapted to a N/A pump, but adding a lot more fuel on an engine without squirters could be a problem.

There is a thread on the GTD list about adding squirters to N/A blocks here:
http://www.vwdiesel.net/phpBB/viewtopic.php?t=11631&postdays=0&postorder=asc&start=0

Initially, there were some internal differences in cylinder head and valve material, and piston crown hardness, between the N/A and turbo engines, but this did not continue for very long, and eventually VW was using the same material for all of the heads and valves. All replacement parts are TD-spec- The only difference in the pistons now is the notch at the skirt cut out for the oil squirter- the crowns are the same hardness.

Another option is ceramic-coating the pistons in lieu of adding squirters. This shows promise but it's really not been tested much yet. The ceramic coating process is becoming quite cost-effective.

Good luck with the project! I'm swapping a TDI with 02J tranny from an '01 Jetta in my '81 Scirocco and will be going with a mechanical pump. I'm having the tranny mounts made and after that it will drop right in like it was made to go there.

Brendan
 

markward

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Joined
Jul 5, 2007
Location
Loxahatchee, Florida
TDI
82 Vanagon and 2011 JSW
Or, you could machine a notch in the connecting rod to allow oil to spray at the bottom of the piston. The side clearance on the rods is so tight and the pressure is so high, I bet they would coat the underside of the pistons no problem. I have also seen other manufacturers drill a hole in the rod bearing area with a jet type insert to spray the piston. BMW and Toyota come to mind. It does not take much of an opening.
 

cujet

Veteran Member
Joined
Jun 5, 2005
Location
Florida, Hurricane central
TDI
2006 Jetta
rsxsr, I used to use drilled rods in my turbo engine builds. They did a great job spraying oil on the pistons. However, they did fail right at the drilled hole if a downshift was missed and over-rev resulted. The non drilled rods never failed at the same location.

One thing that worries me is the RPM the engine turns at my typical 80MPH cruising speed. My current rabbit is downright screaming by comparison to my 06 Jetta TDI.
 

markward

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Joined
Jul 5, 2007
Location
Loxahatchee, Florida
TDI
82 Vanagon and 2011 JSW
I would be leary of drilling the big end of the rod myself. If the OE manufacturer did, I suppose the design includes the hole. Machining a small groove in the thrust surface of the rod would be less likely to weaken the rod. For a conversion, I would think you'd need a 3.67 final drive for conversion. Up though 85 VW used a 3.89 final except for the GTI which had a 3.93. A .78 fifth should give good highway rpm. There was a .71 available at one time as well.
 

cujet

Veteran Member
Joined
Jun 5, 2005
Location
Florida, Hurricane central
TDI
2006 Jetta
rsxsr said:
I would be leary of drilling the big end of the rod myself. If the OE manufacturer did, I suppose the design includes the hole. Machining a small groove in the thrust surface of the rod would be less likely to weaken the rod. For a conversion, I would think you'd need a 3.67 final drive for conversion. Up though 85 VW used a 3.89 final except for the GTI which had a 3.93. A .78 fifth should give good highway rpm. There was a .71 available at one time as well.
I am not sure where to get the proper gears. I have a few transmissions laying around. 4 speed and 5 speed. Most are early 80's diesel Rabbit. Which car has the best (tall) gears? That, of course, is a big part of making it work right.

Thanks!

Chris
 

Lord_Verminaard

Veteran Member
Joined
Jan 23, 2003
Location
Columbus, OH
TDI
2005 NB TDI
Check the tranny codes of the ones you have laying around- you can find it on the bottom side of the bellhousing stamped in the little flat part. Will be a 2 or 3-digit code. If your 4-speed is a GP or GL, you are golden, it has a 3.89 final drive with a .71 4th gear which would work perfectly. When you find your codes, you can look up the ratios here:
http://www.scirocco.org/gears/

Also has a nifty calculator to figure out your RPM vs. MPH with regards to tranny and tire-size.

Brendan
 

janb

Veteran Member
Joined
Jun 19, 2000
Location
Washougal, Wa, USA
020 tranny info
http://www.4crawler.com/Diesel/VW_020_transmission.shtml

I prefer the ASF or ACN for flat land cruising (std gas tranny) I like the AGS for turbo diesel in hilly terrain.

The NA is not a good turbo option and the TD is usually available.
The mechanical heads were different alloy, and prechamber inserts different (Hyd heads (post '85) are ok to use in Turbo application)
+ different pistons, squirters, oil cooler, pan, intake and exhaust + turbo and injectors and pump (oil and injection) so just find a TD to start with, or be happy with the NA. (they are not that bad at sea level)

I am planning to try to make a 75 mpg Scirocco, I have a friend who is up to 62 in his. I will likley use an NA and probably a 4spd, as that is best mileage I've gotten in an IDI. (1.5L w/ low ratio 4 spd running flat out in Rabbit got ~ 60) Injectors and pumps seem to cause the most mileage variance.
 
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