86 Diesel MJ to VW TDI conversion

[johnj92131]

Perhaps a sad end to the Comanche TDI project:  The truck was stolen from my son''s place on Thursday morning, between 3 a.m. and 6 a.m.   No word on the truck, likely too soon to expect any news.

[A-man930]

Oh man! 

[Megadan]

I wanted to jump back and offer a little insight on the turbocharger/clearance issue.  Another possible solution would be to run the manifold from a 2004-2005 Passat 2.0L TDi,  It was also offered overseas in a few other vehicles as well. I actually picked one up for about $80, and they aren't too hard to find, with the worst price I have seen was around $150.  This manifold requires the use of a flange mount style turbocharger, of which the closest to a stock size would be a GTB1749V (VNT17) which is a small upgrade for ALH engines.  They can be found with vacuum or eletronic actuators for fairly cheap and are good for up to 200hp and well past 300ft-lbs depending on tune/setup) with nice fast spool and torque peaking a bit past 2000rpm.  This is the turbo I am going to go with as it is actually fairly cheap and well proven.

Here is a picture from an ALH TDi build using a GTB1756VK 


Installed in the guy's Jetta.


Notice that the turbo sticks out essentially parallel to the ground (perpendicular to the motor) which will ideally place it in the big vast chasm of room at the top of the engine bay.  This should give plenty of room to clear the Jeep motor mounts and give a little more room to run a downpipe for the exhaust. Cost wise it can actually be cheaper than the ALH bolt on VNT17 turbo upgrade, which is usually around $800-900  I have found the GT1749V for $300-400, and toss in say $150 for the above mentioned manifold and at worse you might spend $600.  If you are chasing more power then you could use the GTB1756VK like seen in the above pictures - His car made 201hp@4700rpm and 312lb-ft@2300rpm  to the front wheels - but that turbo costs around 3 times as much.

Anyway, just thought I would toss that info out there for other guys considering this swap. 

I still have a ways to go before I am ready for my TDi conversion- like rebuilding the motor I picked up .  Gotta keep pace with what my wallet can provide after all.  I don't have high aspirations for mine, just around 160-180 crank hp and as close to 300ft-lbs as I can get, which can be done fairly affordably on even the 10mm injection pump (what I have).  That should move a Comanche along with ease, and definitely can't be any slower than my Renix, all while being 180lbs lighter and hopefully getting close to double the fuel economy.

Now to get back on topic a bit. Johnj92131 - I was curious about that water outlet pipe you have.  Was that made or did you find a source for it and bought it?  It wouldn't be too hard to fabricate one, but I am lazy and wouldn't mind spending money if it was cheap enough lol.

[A-man930]

 

 

I definitely want that turbo up and well out of harms way.  

[Megadan]

5 hours ago, A-man930 said:

 

 

I definitely want that turbo up and well out of harms way.  

Glad I could offer a possible solution. Just keep in mind that it will also come down to what version of the TDI you use as there are different flange patterns.  The above manifold should work on the AHU, ALH and BEW Engines. There might be others, but research if you want to use a newer engine than those.  I bought this manifold because I have an ALH waiting on a pallet.

[A-man930]

11 hours ago, Megadan said:

Glad I could offer a possible solution. Just keep in mind that it will also come down to what version of the TDI you use as there are different flange patterns.  The above manifold should work on the AHU, ALH and BEW Engines. There might be others, but research if you want to use a newer engine than those.  I bought this manifold because I have an ALH waiting on a pallet.

 

I also have an ALH.  Thanks again for the info!

[johnj92131]

We got the truck back in mid October.  Full story here:  https://comancheclub.com/topic/56598-sad-end-to-comanche-tdi-project/

 

Had the damaged ignition switch replaced on Thursday.  Cost for parts and labor was $135.  Only problem is that the new ignition key does not match the doors.  Need to be careful not to lock the doors till I have the doors matched to the new ignition key.  So today I parked the truck in the rear of the yard till I get the locks changed.

[Comanche SS]

Dang, the wildernest from across the country is gone?! shame its gone, glad to see the truck is back.

 

[huck731]

maybe this was answered, but I'm at work and didnt read all 6 pages.  I also have an ALH engine thats in a worn out 01 jetta I picked up for CHEEEAAAAAAAP.  did you custom build the trans adapter adn motor mounts or did you purchase them from coty built out of canada, they have kits for the 1.9 PD  engine, but I know mounting wise, the 2 engines are identical.  what did you do for engine management?

 

[johnj92131]

3 hours ago, huck731 said:

maybe this was answered, but I'm at work and didnt read all 6 pages.  I also have an ALH engine thats in a worn out 01 jetta I picked up for CHEEEAAAAAAAP.  did you custom build the trans adapter adn motor mounts or did you purchase them from coty built out of canada, they have kits for the 1.9 PD  engine, but I know mounting wise, the 2 engines are identical.  what did you do for engine management?

 

 

Got the adapter from:  http://gastodiesel.tdconversions.com/adapter/

 

Here is a good thread for a quick summary of available adapters:  http://forums.tdiclub.com/showthread.php?t=494925

[SatiricalHen]

Read the whole thread and it just makes me want to TDI swap mine even more. I'm glad you got the truck back! 

[johnj92131]

Just a quick, short update on March 1, 2019.  Life has been distracting me from the Comanche TDI.  I finally took the truck out of the back yard on January 30 to fill the fuel tank with 20+ gallons of diesel and parked it on the driveway.  Tried to start it a few times in February with out success.  Looked like a battery issue.  Charged the batter for 24 hours but no change.  Managed to jump start it from my son's Ranger, but it would not restart.  So off to Costco to buy their biggest battery.  Installed it, and still no start.  New battery measured 12.64 volts, old battery measured 12.54 volts.  Both should be good enough to crank the engine.  BUT, I am not getting voltage to the instrument cluster, even the clock will not light up.  So the truck sat till last Monday morning when I planned to tow it to a very good auto electric shop.  Just  for fun, I decided to try starting it one more time.

 

You guessed it, the truck started with no problems.  Took it to the shop on Monday and they have not been able to duplicate the problem.  Truck starts every time.  And Yes, I did clean the battery terminals before I changed the battery.  Per previous post, the ignition switch was replaced.  All signs seem to point to a wiring issue between the key and the starter relay.  But, if the problem will not show up at the shop, they can not fix it.  And I sure don't want to be a hundred miles from home when the gremlins decide to show up again.  So the truck remains at the shop till the issue shows up.

 

Oh the joys of old cars, reminds me of my days with British Sports Cars and Lucas Electric systems.

 

Should say that once the truck starts, it is really nice to drive.  Needs more sound insulation, but the TDI engine is a great match for the truck.  More low end torque than the 4.0 for sure.

 

One more comment on Low end torque.  Last August I leased a 2018 Chevy Volt ($254/month for 12K miles/year).  For low end torque, you can not beat an electric motor (maybe a steam engine matches it).  And WAY less noise than a diesel.

[MJPeabody88]

Great write up!! Was considering a diesel swap for the 88 mj. After reading more and more, just seems to be a lot. I guess I’ll just stay with the 4.0

[johnj92131]

5 hours ago, MJPeabody88 said:

Great write up!! Was considering a diesel swap for the 88 mj. After reading more and more, just seems to be a lot. I guess I’ll just stay with the 4.0

 

Definitely less expensive to stay with stock!  The 4.0 is a great engine.

[SatiricalHen]

My Comanche will randomly not start. Not sure what causes it. Once I do start it, it will always start the next time I try. I’ve just put it in gear and roll started it when it acts like that. It’s happened maybe 2-3 times in a little over a year. The guy I bought it from installed a toggle switch to start it with since it happened to him, but I pulled that out since it was so rare that it happened, and being a manual I can roll start. Worst case scenario I could always use a jumper wire and jump the starter.


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[johnj92131]

Picked up the truck from the shop today.  They had it for the week and it started every single time.

 

Next time it happens, I will throw a jumper across the starter relay and see what happens.  So it is keep the jumper wire in the truck and drive it till it happens again.

[Pete M]

On 3/6/2019 at 3:21 PM, SatiricalHen said:

Worst case scenario I could always use a jumper wire and jump the starter.

 

just keep in mind that there isn't a clutch safety in our trucks and if you jump the starter while still in gear it'll run you over.  

[olddude]

I have the same problem, occasionally I turn the switch and nothing. I figure the switch has a worn spot on it after thousands of cycles. So, I put at remote starter button under the hood thinking I would replace the switch when I had a chance. That was a couple of years ago. I'm procrastinating because it is not easy to get to and at 76 years old , I don't enjoy standing on my head.

[johnj92131]

10 hours ago, olddude said:

I have the same problem, occasionally I turn the switch and nothing. I figure the switch has a worn spot on it after thousands of cycles. So, I put at remote starter button under the hood thinking I would replace the switch when I had a chance. That was a couple of years ago. I'm procrastinating because it is not easy to get to and at 76 years old , I don't enjoy standing on my head.

 

Know what you mean.  I am a week short of my 71st birthday.

 

Pete, thanks for the reminder!  Now have 100 km on this tank of diesel.  So far, no issues starting the truck at all since it was back from the shop.

[johnj92131]

Quick update on the TDI Comanche Diesel:

 

280 km so far on this tank of fuel.  Only 180 km driving in the last 6+ weeks.  BUT, zero starting problems in just very short trips close to home.  So the new battery fixed my starting issue.

 

Today, I am taking the truck on its longest trip to date.  200 mile round trip to Orange County.  My plan is to use the phone GPS to check the calibration of the truck odometer.  Once that is done, we will be able to calculate accurate MPG for this tank of fuel.

 

There is one issue with the truck that needs attention before too long.  The stock Jeep factory intercooler is starting to split open at the seam.  No doubt because of the 26 psi boost on the TDI engine compared to the 10-12 psi boost on the factory Renault turbodiesel.  I need to pull off the intercooler and send it to Matt Whitbread.  He will make an all aluminum exact  replacement intercooler for me and the problem will be solved.

 

All for now.

 

[kansashogan]

I'm glad to hear things are going good. 

[Raven]

Awesome conversion. I’m going this route for a summer project. What is your actual fuel economy? 

[johnj92131]

On 5/4/2019 at 9:37 PM, Raven said:

Awesome conversion. I’m going this route for a summer project. What is your actual fuel economy? 

 

Don't know yet is the short answer.  Just have not driven it enough to track it.  Trying to fix that situation now by driving it more now that I have the random no start problem solved with a new battery a couple of months back.

 

One thing I did do to be able to get an accurate fuel economy number was to a 100 km GPS measured drive and compare it to what my trip odometer reading was.  The trip odometer read 111.7 km for the actual 100 km my phone based GPS.  That gives me a correction factor for the next time I fill up with diesel.

 

Frankly, I was surprised that the odometer was that far off.  When I checked the speedometer accuracy on the same drive with the GPS - the speedometer was dead nuts on.  With the speedo reading 100 kph, my GPS said 99 to 101 kpm.  Same thing at 110 kpm - accurate to less than the with of the speedometer needle.  I will be checking it again before I run this tank of fuel out.

 

I intend to run the 23 gallon tank to as close to empty as I reasonably can.  Hopefully, that will be an 18 to 20 gallon fill and a very good reading of fuel economy.

[Pete M]

fuel economy issn't why you do a swap like this.  It'd take a loooooooong time to recoup the money you spent doing it.

 

that glorious diesel sound it makes on the other hand, that is downright addictive   Puts a smile on my face every time I fire up the liberty.   

 

(unless it's super cold out and I forgot to plug in the heater.  Then my face is a mix of fear and terror as I turn the key)

[johnj92131]

On 5/9/2019 at 9:46 AM, Pete M said:

fuel economy issn't why you do a swap like this.  It'd take a loooooooong time to recoup the money you spent doing it.

 

that glorious diesel sound it makes on the other hand, that is downright addictive   Puts a smile on my face every time I fire up the liberty.   

 

(unless it's super cold out and I forgot to plug in the heater.  Then my face is a mix of fear and terror as I turn the key)

 

Pete,

You are SO RIGHT about the payback.  Just did a quick calculation.  Assume 20 mpg in a 4.0 and 32 mpg in the TDI.   (These numbers make the calculation easier).  Right now, both RUG and D2 are about $4/gal.  RUG costs me about 20 cents per mile. Diesel costs me about 12.5 cents per mile.  Saving me Seven and a half cents per mile.  So after 100,000 miles I will save $7500 in fuel costs.  Still way short of what this project has cost at this point.  More important, at 4K or 5K miles per year, the payback is 20 to 25 YEARS or more. 

 

My original plan was to use the diesel and the Wildernest Camper for a road trip to Alaska.  But the car thief got rid of the Wildernest.  Still have a SnugTop, which can work.  But no where near as nice as the Wildernest.  Oh well, that is life.