1986 diesel Jeep Comanche TDI conversion

john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
My search for an original diesel Jeep 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 Jeep 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.

Last June I finally located a real factory equipped 1986 Jeep Comanche with the Renaullt 2.1 Turbo Diesel engine for sale on Vancouver Island in British Columbia. The truck was in very nice shape, but the Turbo Diesel engine was a total basket case. Literally the bed of the truck was filled with multiple failed parts from several Renault engines and transmission. The truck was listed as a parts truck and the price was right. After verifying this was a legitimate, factory diesel Comanche, and viewing a number of pictures, I purchased the truck.

Then 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 Matt Whitbread’s shop in northern Michigan to begin the TDI engine conversion over the winter.







After dropping the diesel at the shop, the plan was to drive to the airport in Chicago, park the `91` Comanche and fly home. The drive the 96 Passat engine doner to Chicago, pick up the Comanche and tow the Passat to the shop for the engine transplant.

Things did not go quite as planned. The Passat lost a head gasket 150 miles into the trip. So I rented a car to get home, then flew back to Chicago to pick up my Comanche at the airport.
From there, I went on to the TDI Club's annual convention in Sturgeon Bay Wisconsin. While there I got a line on a 98 TDI engine at a good price. Best news was it was just an hour away from me. So Sunday I made a 3 hour side trip and purchased the engine. Here it is in the back of the Comanche:





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



Renault engine ready to be pulled out:



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:

 
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turbobrick240

Top Post Dawg
Joined
Nov 18, 2014
Location
maine
TDI
2011 vw golf tdi(gone to greener pastures), 2001 ford f250 powerstroke
Sweet. My first truck was an '87 4x4 MJ 2.5L. Loved it. Never seen a factory diesel. Good find! That renault motor must have been pretty weak if they mated it to an AX5.
 

john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
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.

https://youtu.be/Gkyb3PRWwbk


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.

TDI engine stripped down to long block, prior to being resealed.






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 (by Giles at Performance Diesel in Tronto) 11 mm injection pump and a set of fresh, larger nozzles (from Bora Parts and DFIS) are ready to go in when the head comes back from the shop.


Other items waiting to be installed include:


Engine adapter from http://gastodiesel.tdconversions.com/

New 4.0 flywheel, pressure plate, heavy duty Luk clutch, new master and slave cylinders.

New 4.0 exhaust system ordered to replace the 31 year old rusty one. Whitbread to build custom down pipe.

Good, used 2 wheel drive AX-15 was purchased and delivered. Yes, the truck is a 2 wheel drive.



 
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CRSMP5

Veteran Member
Joined
May 18, 2009
Location
NE OHIO
TDI
idi
oil feed port to head is at #3 and the hg seeps oil right into#3 ive had them seep so much it forms a trail of oil right out the exhaust valve.. hence i doubt its a valve stem seal issue... it seeps between the layers of the headgasket
 
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xjjeeper

Well-known member
Joined
Mar 20, 2016
Location
Chilliwack BC
TDI
99.5 golf, soon to be Tdi Xj
Sweet! I remember seeing that Comanche for sale a little while ago. I live in Vancouver and concidered going to check it out. Good luck with the swap! :)
 

john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
Sweet! I remember seeing that Comanche for sale a little while ago. I live in Vancouver and concidered going to check it out. Good luck with the swap! :)
Yes, this truck has been sold 3 other times since 2013, before I finally got it. It ran (somewhat) in 2013. Think I have an old video. But each of the last 3 owners has tried to "fix" a Renault engine, only to end up with more broken/spare parts. The bed was full of them.
 
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john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
The cylinder head is back from the shop. Next step is to check and replace the rod bearings. Will see if we need stock rod bearings or .001 oversize rod bearings to just tighten up clearances a touch. Plan is to use 12.9 head bolts when the head gets put back on rather than the stock TTY bolts. The 12.9 is both stronger and much less expensive than the VW TTY bolts.

More pictures next week.
 

john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
Progress pictures:

Cylinder head after trip to machine shop.



First coat on the block.



Should make spotting oil leaks easy, right.




Head is back on with 12.9 bolts. Piston protrusion was all within .005 group and required a 2 hole gasket.

Rod bearings get replaced next.

EGT probe has been ordered from Ebay. Manifold will be drilled/tapped for EGT probe.

Starting to shop for upgraded turbo. Looking for GTC1549VZ or GTD1752VRK.
 
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vanbcguy

Veteran Member
Joined
Feb 22, 2013
Location
Vancouver, BC
TDI
'93 Passat - AHU mTDI with GTB1756VK
Yeesh I just got my GTB back on the road, now we've gone all the way to GTD??

Sent from my XT1097 using Tapatalk
 

john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
Latest update pictures from Whitbread's shop

Matt says: " [FONT=&quot]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. "[/FONT]



See the nice, rebuilt 11 mm pump from Giles at Performance Diesel:




Front view:

 
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john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
Latest progress and a new issue.

First the issue. See the pitted transmission input shaft? Emery cloth did not help. Pits are too deep.



Fortunately, Whitbread had another AX-15 input shaft left in the shop from another customers TDI/Toyota conversion. So Matt took a couple of hours time to open my trans and swap out the input shaft. In the process he found water at the bottom of the transmission. Likely from when I stored the transmission in my back yard last November and December. The heavy California rains got past my Harbor Freight tarps.



Here it is all back together.



Adapter and new Jeep flywheel mounted on the TDI engine.



Clutch and pressure plate mounted, ready for the AX-15.



One more small issue - need a replacement lower timing cover. Put an ad in Classifieds.



And that is it for the Tuesday update. Looks like Whitbread is getting close to test fitting the power train into the Comanche.

For me, it is back to working on Income Taxes - I will be busy most of the weekend with that. !!
 
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xerootg

Veteran Member
Joined
Oct 20, 2015
Location
North Bend, WA
TDI
Mk7 Golf Sportwagen, BHW Jeep XJ
This is going to be a neat truck when your done! Are you going to do any of the late model modifications like the interior or front clip?
 

john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
This is going to be a neat truck when your done! Are you going to do any of the late model modifications like the interior or front clip?
Once Whitbread is done with his magic and the truck is driven back to California, we will see what else it needs to make it truly road worthy and dependable for a trip to Alaska by summer 2018.

Right now, I have a set of Hella E-Code headlamps, a new headliner, a Lund Visor and a couple of other things stashed in the garage for the truck. Not sure if I will use it, but I also have a complete Wagoneer front header panel, so that is a possibility

Late model doors will go on the truck, if it ever gets properly painted. Until very recently, I never considered the 97+ interior worth the effort. But this truck does not have factory A/C and I really want that for the truck.
With all the work required in the dash area to add A/C - doing the 97+ interior conversion might be very minimal extra work. At the same time, all that 30+ year old Jeep wiring could be replaced.

The problem is, these projects are just one big slippery slope and money pit. But I am in this far, right?

This week, Matt should start to test fit the power train and I have to finalize my choice of turbo upgrades.

Just a quick progress update.

The transmission is back together and bolted to the engine. See picture below.

 

xerootg

Veteran Member
Joined
Oct 20, 2015
Location
North Bend, WA
TDI
Mk7 Golf Sportwagen, BHW Jeep XJ
Good deal man! I've owned 5 cherokees so far, and the late model interior is worth it to me. There are a couple options for the dash instruments if you do decide to make that jump. First you can use the autometer dash insert and use individual gauges, and the second option is I'm also finalizing my can-ccd translator board layout. I'd love to send you one once it's a little more refined!
 

john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
GTD . GTD . GTD all the way! :D
Sorry Dave, no GTD this time.

After lots of shopping for turbochargers, here is what I discovered.

GTD1752VRK turbos are still new on the market. So not much available supply. Offered used prices were right at $800 delivered to the U.S.
New prices ranged from $790 to $975 delivered to the U.S.
B3achbum found a link to a turbo rebuilder offering a GTD1752VRK rebuilt for about $425 plus a core deposit. Unfortunately, he was out of stock at the time. Or I would have grabbed it!

2 or 3 years ago, GTC1549VZ turbos were new and in short supply on the used market, even in Europe. Then it cost $8-900 to get one used. That is the price range I paid for the turbo in the Passat.

Well, the market has changed. Ebay.uk has 10 to 15 GTC turbos listed just about every day, new and used. The used prices are $400 or less. I just ordered a good used GTC1549VZ for $275, delivered on Ebay.uk - Very hard price to resist! (Same one you pointed me too, I think). Ebay seller has perfect feed back rating, so we will see what the turbo looks like.

The GTC is just too cheap to pass up. Whitbread asked how much I was willing to spend for an extra 15 or so horsepower. The extra $5-700 will still get spent on other required parts for the Comanche. Besides, we know the GTC1549VZ works great and we spent several hours of dyno time dialing in the tune.

Nozzles will be Race 520, set for low smoke and the 340 pop pressure you suggested. May be tempted to push the boost up to 30 psi from 25/26 on the second tune.
 
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john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
Just as the TDI engine and transmission were being test fitted for the very first time into the Comanche, we hit a bump in the road in the form of the old AX-5 transmission mounting bracket from the 86 truck does not fit the new, stronger AX-15 transmission. So I asked Whitbread to move on to someone else's work while I search for the right part. That was April 22.

AX-5 bracket below.




AX-15 bottom side where bracket mounts




Here is the correct bracket I needed. It is on the right in this picture.

[/IMG]



Searching the Jeep parts catalog in the transmission section comes up with nothing even close. Google search come up with something called "AX15 Torque Arm Bracket" with a part number that is no longer available.

A request for help on the Comanche club get the correct page and diagram for the part we need. The diagram is in the "engine" section of the parts book. NOT the transmission section - no wonder I couldn't find it. After a search with the right part number - we find it is a discontinued part. So back to Google and to Ebay looking for the part. Found one on Ebay for about $200. So I keep searching with not much more luck.

Post another request for help on the Comanche club and in less than a day - the needed part is offered for $20 plus postage. Aren't these online forum guys great at helping out? The part was mailed Monday morning and arrived Wednesday afternoon. Bingo - we are back in business. Except Matt is working on another customers car now. (Remember, I asked him to move on from my car).

May 4, the postman delivered the GTC1549VZ turbo. Whitbread say the turbo looks good. Yea! Also, he will be back on the Comanche project this coming week.
 
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john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
First picture of the GTC1549VZ in it's new home. Really is a great fit on the engine. You can see the adapter plate between the stock AHU manifold and the turbo. Straight shot from the turbo to the stock Comanche intercooler. No clocking the turbo required. Just a nice, simple, clean installation.




Top view of the turbo installed.




Engine test fit into the engine bay.




This plate is the start of a custom motor mount.




Next problem. Whitbread asks if I really want air conditioning on the truck?
Yes! I certainly do. Why do you ask?? Notice the steering column and the A/C compressor?




So I asked about mounting the a/c on the other side of the engine? Unfortunately that would be right in the way of the turbocharger. So that is not the solution. More on this later... when the problem gets solved.. I hope any way.
 
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TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
Joined
May 1, 1999
Location
Canada
TDI
TDI
AFN B5 A4 has the AC compressor on the passenger side of the engine below the turbo - should be fine no? Can take pictures if desired. BHW bracket should be similar.
 

Rockwell

Veteran Member
Joined
Nov 23, 2009
Location
Manchester, NH
TDI
2003 Jetta TDI (R.I.P.), 1.6TD Toyota pickup, 2011 BMW 335d, 1996 Passat TDI
Next problem. Whitbread asks if I really want air conditioning on the truck?
Yes! I certainly do. Why do you ask?? Notice the steering column and the A/C compressor?

So I asked about mounting the a/c on the other side of the engine? Unfortunately that would be right in the way of the turbocharger. So that is not the solution. More on this later... when the problem gets solved.. I hope any way.
If there is little to no angular rotation at the steering U-joint you can replace it with a rag joint maybe. It's a little more compact and should sit closer to the steering box to clear the A/C clutch.
 

john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
Great ideas, both of them.

Matt was going to look at reversing the transmission cross member to move the engine over a couple of inches. He was worried about screwing up the turbocharger path by moving the a/c to the other side of the engine. So, Dave if you wouldn't mind sharing the picture of the AFN a/c mount that would be great.

Rockwell, never saw a rag joint before. Very interesting solution. Thanks for that pointer. Where do I get one??
 

Rockwell

Veteran Member
Joined
Nov 23, 2009
Location
Manchester, NH
TDI
2003 Jetta TDI (R.I.P.), 1.6TD Toyota pickup, 2011 BMW 335d, 1996 Passat TDI
I just did a quick google image search. If you search around you should be able to find something you can make work. Just need to figure out spline count.
 

john.jackson9213

Top Post Dawg
Joined
Mar 14, 2007
Location
Miramar, Ca. (Think Top Gun)
TDI
1996 B4V
Hey John - I have a BHW AC bracket and belt tensioner that I didn't end up using - let me know if you have a need for it.

I am not sure if would fit the AHU/1Z. Whitbread would also have to make up something like Jimbote did to mount an extra pulley on the harmonic balancer.

Look at post #93 here: http://forums.tdiclub.com/showthread.php?t=293577&page=7 for more details.

That is a good post. If the simple stuff doesn't work, I will be looking for that mounting bracket. But as of now, he is going to move the engine over first and see if that works.
 

All Stock

Veteran Member
Joined
Oct 6, 2014
Location
Michigan
TDI
AHU
You can find 20 brackets for that on eBay.
The bhw will not work..thats the newer block.
It's from an early 1.8t in the Audi A4 as well as the Passat. They used the old style block.
It is a bolt on and go.
 
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