86 Diesel MJ to VW TDI conversion

[johnj92131]

It is time to start documenting the history and progress of this project.  The search for an original diesel Comanche started 6 or 7 years ago.  After a couple of conversations with the California DMV and BAR about attempting to do a diesel conversion on my 1991 Comanche I quickly figured out that the best thing for me was to find a real 1986 or 87 original MJ diesel.  It simply avoided a whole lot of issues in California.

 

Some of you may have seen my thread from last summer with pictures of me towing the 1986 Diesel Comanche I purchased in Victoria, B.C to the shop in northern Michigan that will be installing a Volkswagen 1.9 TDI engine in place of the broken down Renault 2.1 original Turbo Diesel engine.

 

Here is a link to that part of the Comanche's journey with a couple of pictures along the way:

 

http://comancheclub.com/topic/51141-86-diesel-mj-on-its-way-to-new-home/?hl=victoria&do=findComment&comment=521006

 

I drove 1200 plus miles from San Diego to Victoria on Vancouver Island to pick up this truck and then towed it 2000 more miles to northern Michigan.

 

Since 2013 the truck has had 3 different owners before I purchased it last summer and has been offered for sale at least twice here on the Comanche Club by different owners.  Here is the first time the truck showed up on the club.  Notice that the truck ran in 2013 and that  IslandXJ did put some work into the truck before he lost interest and sold the truck:

 

http://comancheclub.com/topic/40422-86-diesel-mj/

 

By August 2015 the truck was offered for sale by the second owner. 

 

http://comancheclub.com/topic/48148-diesel-5-spd-low-milage-vancouver-island/?hl=diesel

 

This time I spoke at some length with the seller but I passed on the truck because of the price and a third owner purchased the truck in September 2015.

 

By June 2016 the third owner listed the truck For Sale on the Victoria, B.C. Craigslist.  By now the truck was advertised for parts and not running.  After several phone calls, fresh pictures and verifying both the registration and the VIN number as a real factory diesel MJ I purchased the truck via PayPal and otherwise unseen.

 

The purchase price was $350 Canadian or about $286 U.S.

 

More info and pictures of progress will follow in the next week or so as I gather some pictures.

 

 

 

 

 

[johnj92131]

In mid February, it was finally time to get the 86 MJ into the shop and out of the Michigan winter.
 
 

 
Renault engine getting ready to be pulled
 

 
It is out!  2.1 TD and AX-5 on the floor
 

 
 
Cracked cylinder here and a crack in the cylinder head explain the problems with the 2.1 TD engine
 

 
The now empty engine bay
 

 
 
Next attention moves to the VW TDI engine. Here is a link to a quick video of the TDI engine running on a test stand. This was
simply a test run to see what might be wrong with the engine.

Lots of smoke, but the engine does run. Next step is to replace all the gaskets, a new timing belt, new water pump and a rebuilt
alternator. The original alternator was frozen - so it was sent to a rebuilder.

[johnj92131]

Updated March 7, 2018

 

 

TDI engine stripped down to long block.

 

 

 

Notice the problem in exhaust port #3?  See all that carbon?

 

 

 

 

A  cylinder leak down test showed the rings to be in good shape.  So the head was pulled.  Inspection of the cylinder bores shows original factory cross hatch pattern still visible in the bores.

 

 

 

Inspection of the cylinder valves shows likely oil leak in the #3 exhaust valve.  See the wet area around #3 valve. Brown stuff is cardboard from the head being put on a sheet of cardboard to avoid damage to the head surface.

 

 

 

So the head is off to the machine shop to be freshened up and new valve seals.  A new head gasket and upgraded head bolts will be ordered before the head goes back on.  The cam and lifters look great, so will be reused.  This will mean a 2 week or so work stoppage. In the mean time, a freshly rebuilt 11 mm injection pump and a set of fresh, larger nozzles are ready to go in when the head comes back from the shop. Both items will add to the engine torque and horsepower.

[johnj92131]

One more Reserved for future update

[Siopposition]

Looking forward to seeing this!

 

It was great meeting and talking with u

 

Sent from my SAMSUNG-SM-G891A using Tapatalk

[A-man930]

Good to see some documentation here on CC. Get that kitchen done!

[johnj92131]

Good to see some documentation here on CC. Get that kitchen done!

 

That is xerootg on TDIClub who is finishing his kitchen this month.  Got our kitchen done last summer with a good contractor.  :laughin: :laughin:

 

See the pictures of the interior on this link for the interior color to make the new headliner:

 

http://comancheclub....2-86-diesel-mj/

 

Your stock color should be fine to match the 30 year old faded "porno red".

[A-man930]

Nothing like ASSuming right? lol

[johnj92131]

More pictures added March 7 to first couple of posts.

[Minuit]

Wow, that 2.1 is impressively spanked. Is that a common problem with those, or did it get really, really hot? Great story and a solid looking truck, I'll be following this for sure.

[Tex06]

Haha, the 2.1 uses the same fuel filter as the 6.2L Chevy diesel.

[johnj92131]

For future reference, I am posting the truck VIN number and how it decodes using the factory service manual.

 

VIN   1JTBW6678GT092562

 

1 - Manufacturing Country :  United States

J - Company/Make:  Jeep

T- Type:  Truck

B- Engine Type:  2.1L Turbo-Diesel I4

W- Transmission: 5 spd. Flr. Shift (2WD)

66- Series: 2WD Comanche

7- Trim Package: X    (F,G,H, or J would each indicate Metric Ton Package)

8- Check Digit

G- Model Year:  1986

T- Plant of Manufacture: Toledo, Ohio

092562- Sequential Number

 

Diesel engine was not offered for sale in California.  No wonder they are so difficult to find in California.

Truck has the optional 23.5 gallon diesel fuel tank, with the 3 straps.  See picture below.

Need to figure out the rear axle ratio.  Shop manual lists 3.54 to 4.10 as available. Not sure the tag is still on the axle after 30+ years.  May have to pull the cover and count teeth.

No factory a/c - Not sure it was offered with the diesel engine.  Can anyone verify this?

 

[DirtyComanche]

Wow, that 2.1 is impressively spanked. Is that a common problem with those, or did it get really, really hot? Great story and a solid looking truck, I'll be following this for sure.

 

It's a common problem, that might be something of an extreme case.

 

I was very close to hopping on a plane to go get this thing when it was a few owners back.  Discussion with the then owner lead me to realize it had much more major issues than it appeared on the surface.

 

At least it's now with somebody that will fix it.  A TDI should be pretty freakin' awesome in one of these trucks, and I've definitely thought about it for my own 86...

[johnj92131]

 

I was very close to hopping on a plane to go get this thing when it was a few owners back.  Discussion with the then owner lead me to realize it had much more major issues than it appeared on the surface.

 

 

Please do tell me anything else you remember about the issues with this truck - besides the engine.  It may help me avoid a problem or two on the road.

 

Thanks,

 

JJ

[cody4359]

You can check the gear ratio by marking the yoke/pinion and rotating the tire 2 revolutions and counting how many times the yoke spins. Also, mark your tire and ground to get a accurate number

 

Sent from my SM-G900V using Tapatalk

[DirtyComanche]

 

 

I was very close to hopping on a plane to go get this thing when it was a few owners back.  Discussion with the then owner lead me to realize it had much more major issues than it appeared on the surface.

 

 

Please do tell me anything else you remember about the issues with this truck - besides the engine.  It may help me avoid a problem or two on the road.

 

Thanks,

 

JJ

 

 

The engine and the body was all I discussed with him.  I literally have every other driveline part available or procurable as a spare, and thus didn't care.  I wanted a clean body, and it wasn't perfect, and once I started getting into the issues regarding it pressurizing the cooling system I realized it wasn't a simple fix to make it drive.  I bowed out from there.

 

I think you'll find most of the front axle, steering, and suspension is worn out though.  It's at that point in it's life.  But those are all parts you can just buy from a parts store, Rockauto, Summit, Quadratec, etc.  IMHO no big deal.  The truck seemed solid from talking to him on the phone, save the engine being roasted.

[johnj92131]

Just a quick update.  Pictures will follow next week or so.

 

Cylinder head is back from the shop and looks much better now. 

 

 

Rod bearings will be checked, clearances measured, then replaced with new bearings.  Either standard size or .001 oversize.  Block gets cleaned and painted late this week.  Next week the engine gets put back together with all fresh seals/gaskets. This will help sort out any new oil leaks in the future.

 

The postman delivered a new headliner on Monday for the truck (Thanks to the group buy from SMS).  Last month I finally got a Comanche specific Lund Visor for the truck. Both these Items will be on my shelf till the TDI conversion is complete and the truck finally gets registered in California.  Also have a Wagoneer front end that may wind up on the truck also.

[A-man930]

Rod bearings will be checked, clearances measured, then replaced with new bearings.  Either standard size or .001 oversize. 

 

I'm gonna take it you mean .001" undersize to compensate for a bit of journal wear?  Oversize would be used if the big ends of the rods were worked on... 

[johnj92131]

 

 

Finish color on the block:

 

 

 

Head is back on the block with a standard 2 hole head gasket.  Piston protrusion measurements were within a .005 range, nice and tight grouping.  Next the engine gets flipped on the stand and the rod bearings get replaced.  Exhaust gas temperature probe has been ordered.  Manifold will be drilled to accept the probe.

 

Started shopping for an upgraded turbocharger from Europe.  Looking to buy a turbo from a 170/177 hp. 2 litre Audi or VW or from a 190 hp 2 litre BMW 320D. 

[A-man930]

Started shopping for an upgraded turbocharger from Europe.  Looking to buy a turbo from a 170/177 hp. 2 litre Audi or VW or from a 190 hp 2 litre BMW 320D. 

 

Is this the VNT17 I keep hearing about?

[johnj92131]

 

Started shopping for an upgraded turbocharger from Europe.  Looking to buy a turbo from a 170/177 hp. 2 litre Audi or VW or from a 190 hp 2 litre BMW 320D. 

 

Is this the VNT17 I keep hearing about?

 

 

No.  The VNT17 is a bolt on upgrade to the ALH VNT15.  The ALH engine was last used in 2003, but still very popular and reliable.  The 1Z and AHU engines are older than the ALH by 3 or 4 years and did not have a VNT turbo (VNT = Variable Nozzle Turbo).  The older engines used a wastegated turbo, not VNT.

 

The GTC1549VZ turbo is about 2 generations newer than the VNT-17 and was never sold in North America.  The GTD1752VRK is 3 generations newer than the VNT-17, also never sold in North America  Both of these turbos support more top end horsepower and spool quicker at the low end than the VNT-17.   That means a broad, flat torque curve.  As an example, later Audi/VW diesels report peak torque over a range of 1750 to 2750 rpms, rather than at 1900 rpms.   The GTC turbo pushes enough air to support 200-210 horsepower.  The GTD turbo will support 220-235 horsepower.  Both Turbos require some custom work to mate to the ALH, AHJ, & 1Z engines. 

 

For the last 18 months, I have been running a GTC1549VZ turbo on my 96 Passat with close to double the stock horsepower and I have been super pleased with the results.  Very, very little turbo lag and smooth power to 4500+ rpm.  We had to dial back the power because the clutch would start to slip at 313 lb/ft of torque.  The tune is now putting out 285 lb/ft with no clutch slipping. Max boost pressure is held to 26 psi, in the interest of keeping the head gasket in one piece.  The 285 lb/ft is at the front wheels on the dyno.  The H.O. 4.0 puts out 230 lb/ft at the flywheel, not the rear wheels.

 

With this engine for the Comanche, the stronger 12.9 head bolts will keep the gasket in place for more than 30 psi boost.  The AHU pistons are said to be a bit stronger than the 1Z pistons also.  The larger Jeep 4.0 LUK H.D. clutch "should" support more torque than the stock VW VR6 clutch.  All in all, the thinking is that the GTD1752VRK turbo will be able to deliver the same or more torque at lower Exhaust Gas Temperatures in the Comanche compared to the GTC1549VZ in the much more aerodynamic Passat.

 

Sorry for the long winded response.

[A-man930]

 

Sorry for the long winded response.

 

 

No, thank you for the thorough response!  With almost 400k on this engine I really don't have a lot of confidence in the turbo on my ALH (VNT15 I assume) so I'll probably be replacing it during the swap.  What the replacement turbo is exactly is up in the air at this point...

 

Both Turbos require some custom work to mate to the ALH, AHJ, & 1Z engines. 

 

I'd be interested to know what modifications are needed.  Will the ALH ecu be able to control it?  Does it still bolt up to the head?  Is the EGR port still in the correct location?  Will any of this fit in our engine bay whilst using EVguy's mount arrangement?  

 

Don't feel obligated to answer here and clog up this thread but you've piqued my interest for sure.  Keep it up!   :thumbsup:

[johnj92131]

Good news this morning about the crankshaft and the bearings.  Whitbread says: "Yeah, all the old bearing looked great. Mains plastigauged right at .002". Put all new stock main, rod, and thrust bearings in. Turns over perfect."

 

 

 

Nice, clean, rebuilt 11 mm fuel injection pump from Performance Diesel in Toronto.

 

 

 

Front view of the engine.

 

[A-man930]

This Whitebread guy keeps popping up everywhere it seems. Is he doing the engine work at his place?

[johnj92131]

This Whitebread guy keeps popping up everywhere it seems. Is he doing the engine work at his place?

 

Matt is a darn good fabricator who has been working on/playing with VW diesels for years.  So he knows them inside and out.  This is the third and biggest project I have had him do.  He did the custom turbo upgrade on my Passat in September, 2015 - it has been flawless.  I also relied on another fellow on the TDIClub for engineering advice/guidance.  The guy is a real world, professional Phd.level, engineer with diesel research experience in Europe.