And yet another Toyota swap, but M-Tdi.

Blue4R

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Joined
Apr 14, 2013
Location
Mission Viejo
TDI
2013 passat tdi dsg
Thanks for the reply. I'm hoping to swap my 84 4runner this year and I'm still trying to decide if there is any reason to do a TDI vs. an M-TDI
 

vanbcguy

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Joined
Feb 22, 2013
Location
Vancouver, BC
TDI
'93 Passat - AHU mTDI with GTB1756VK
Frankly the M-TDI with the Rover pump works so well and is so simple to set up I really can't see bothering with the hassle of putting the wiring in to a non-vw chassis. Just sorting out the pedals and things would be hassle enough. My Rover-pumped AHU runs AWESOME with the factory Rover pump settings.
 

JaysinSpaceman

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Aug 5, 2008
Location
Skull County, Ca
TDI
Golf
To be perfectly honest I don't believe one is better then the other. If you have a complete donor car then I would say that the Tdi is easier then the M-Tdi. There might be a lot of wiring to sort with electric but there is no need to reinvent the wheel like there is to go mechanical. If you are more mechanically inclined (like me) then it's not bad to tear into a VE pump and swap/modify parts to make a mechanical pump and realistically there just isn't enough computer control in the electric VE pumps to make them that much better, maybe a wee bit smoother at idle and a wee but more efficient control of a VNT turbo but until these motors got away from the VE style pump there just wasn't that much that a computer could do better then the mechanical counterpart. When you talk common rail that is an entirely different story and they have a great deal of control and it is a completely different animal. But I don't feel that electric VE vs. mechanical VE is much of a leap.

When common rail Tdi engines become readily available and reasonably priced I might really consider changing out my M-Tdi for a common rail motor but until them I like the mechanical system. I would definitely do so if someone would come up with a stand alone computer to run the fuel system that gets rid of all the superfluous electronic garbage that is so integrated into the common rail cars, ie; special key, instrument cluster, air bag, DPF, etc, etc, etc...

Jaysin
 

JaysinSpaceman

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Location
Skull County, Ca
TDI
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I wanted to update this thread so it didn't die. There isn't much to report as everything has been doing pretty well. I have still been finishing up the little stuff and working bugs out but it seems to be going good. MPG is hovering around 30, which is pretty good considering the very rugged mountain region I live in.

I have a couple of questions. (this first one is really more of a request) I have been tuning and playing with a lot of pump adjustments. Mainly the timing. I seem to have found a sweet spot I can check the lift at TDC but I don't know what this equates to as far as crankshaft degrees. I would love to get a Diesel Timing Light adapter but I am short on the 200+ dollars they cost (mostly because I already spend too much on tools). I was hoping to find out if someone out there might be willing to rent their timing light adapter to me for a week or so, I would happily pay shipping both ways and something for the tool rental. I have a stock TDI that I can compare the M-tdi timing to and see how they are similar or different at idle and various rpm.

Next. I know that before you shut down a Turbo Diesel you should let it idle for a bit to keep the turbo bearings from coking up. My question here is how long or what EGT level is a safe level for shut down. Currently I let it idle for 30-45 seconds until the EGT gauge reads 400F or less. My driveway is long and very steep so when I hit the top of the hill and park the egts are typically about 6-700F and I feel this is too high to just shut it off. So what do you do and what is considered a safe EGT level to ensure that the oil in the turbo doesn't coke up?

As soon as I finish some customer work I will have some interior updates as I got the material to finish the cab interior and with a little sewing and luck I will be able to get the rest of the rear cab fabric lining and insulation done.

Thanx for the input,
Jaysin
 

libbybapa

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Nov 15, 2011
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Where?
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'83 AHU mTDI high top Vanagon, '84 AHU mTDI pop top Vanagon, '85 Franken-mTDI Adventurewagen Vanagon, '91 Vanagon ALH mTDI tin top auto, '02 Jetta eTDI Wagon, '02 Jetta eTDI Sedan
There is no 're-inventing the wheel' when going mTDI. It is a lot less reinventing than doing the eTDI into a different chassis.

Your intermediate shaft bearing mod is interesting but I think you might not have considered that the IM shaft spins CCW unlike the other sprockets and so placing the oiling hole at 4-5:00 places it on the trailing edge of the thrust area, not the leading edge. Leading edge would be 7:00.
 

JaysinSpaceman

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Libby,

I am aware that the I-shaft turns CCW and the 4-5:00 position puts the oil hole about 60-90 minutes before the highest loaded area of the front I-shaft bearing. Installed at 7:00 the oil hole would be too far out in front of the loaded area of the bearing, it would be better then where the oil hole is from the factory but still too far for the oil to be adequately drawn under the loaded side of the bearing.

As for "reinventing the wheel" I simply mean that one needs to learn about and completely understand the inner workings of the VE pump and injection theory to do a M-Tdi successfully and end up with a powerful and efficient swap. The electronic swap is more only a matter of sorting a lot of wires out an making it fit. So far I love my M-Tdi swap and I would not do it different if I had to do it over again. (Maybe I'd do a Common Rail but one would really have to reinvent all the controls.)


Does anyone have an opinion on the EGT range for safe shut down so that the turbo doesn't coke up?

Thanx for the input,
Jaysin
 

libbybapa

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Nov 15, 2011
Location
Where?
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'83 AHU mTDI high top Vanagon, '84 AHU mTDI pop top Vanagon, '85 Franken-mTDI Adventurewagen Vanagon, '91 Vanagon ALH mTDI tin top auto, '02 Jetta eTDI Wagon, '02 Jetta eTDI Sedan
I see what you are saying about the oiling hole. That makes sense.

What you are saying about mTDIs does not make sense. Someone installing an mTDI does not need to know anything at all about the inner workings of the pump. As Bryn just said, the Land Rover pump works fantastically well out-of-the-box as does the LT pump or any other mTDI pump made by anyone worth their salt.

I always idle down to 300°F.
 
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JaysinSpaceman

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Libby,

I am not trying to be argumentative but when I started this project there was very little M-tdi information being shared by those that had done it. I also had no desire to shell out $1200+ for a "custom" pump work up, so I had to learn how everything worked and build the pump myself. It wasn't until well after I built my pump that the info about the LT and Rover pumps even came to light. I have since looked for these two pumps and haven't found one in the US for a reasonable price, the last Rover pump I saw on eBay was like $1600 and supposedly rebuild by the owner which made me wonder why it was being sold.

Anyway, I love my M-Tdi conversion and would do it the same again. I think the the electronic VE pump isn't really worth the headache of the wiring because the ECM has so little control of the engine other then being able to retard timing a bit and easier operation of the VNT turbos (and I am working on a mechanical way of doing that without all the levers and rods that are common with M-tdi/VNT turbo swaps). The only way I would do an electronic swap is to use a common rail Tdi anything less should be mechanical.

I also think that to tune a M-Tdi does take knowledge about all aspects of diesel engines and a good set of gauges (egt, boost, etc...) in order to tune them without blowing them up. If you want to not ever get your hands dirty then the M-Tdi might not be your cup-o-joe but I love all things mechanical.

Jaysin
 

410onefour

Veteran Member
Joined
Sep 28, 2008
Location
Jasper alberta Canada
TDI
2003 jetta tdi wagon, 1991 toyota mtdi
I did the MTDI as well and truly loved it. I learned so much about the Bosch VE pumps by building my own MTDI. That part alone was worth the effort. Adding the vnt turbo and controlling it mechanically made it all worth it in the end. The power my pump produced in the end truly amazing. Keep up the great work JaysinSpaceman. BTW, I love your intermediate shaft bearing mod. Very well thought out.
 

JaysinSpaceman

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Joined
Aug 5, 2008
Location
Skull County, Ca
TDI
Golf
Well, I have an update.

All was well after the replacement of the Intermediate Shaft bearings and I put about another 2700 miles on the truck. Then the other day (about a week ago) I noticed a noise that wasn't there before but I couldn't pinpoint it. One of my friends listened to it and my wife listened to it and said that it just sounds like a diesel. I took my wife for a ride and then she commented that maybe there was a noise there but it was really subtle. This whole time I am thinking that I might me nuts and hearing things (my actual hearing is horrible so it wouldn't surprise me). I adjusted the timing and ran some Diesel Purge injector cleaner through it. And then I took it for a test drive...

On the way back up my long steep driveway as I rounded a corner it felt like I ran over something and the engine hiccuped. It continued running and as I finished up the driveway I noticed that the oil pressure had dropped. Long story short, I found my noise...





Apparently the TTY (torque to yeild) main cap bolts couldn't hold back the forces that a bigger turbo, bigger injectors, and bigger injection pump head make. More power, arr arr arr!

It punched one main bolt through the windage tray.


Here's where the cap used to live.


And if you look close here you can see the ends of the two main cap bolts still in their holes in the block.


So needless to say I get to build a new engine. I think I have a core short block lined up (FrankenDiesel and his friend Ben are kind enough to look through their stash for me) and I am getting all the research done to order all the new bits 'n' pieces. It will be getting ARP main and head studs, Rosten rods, sputter bearings, rebuild my head and likely a new set of oversize pistons with ceramic coating from Swaintech (another part from FrankenDiesel). The old block and crank will make a good boat anchor.

I will update as I put the new motor together and hopefully this one will be bullet proof.

As a side note until this happened I was very happy with this engine in the truck and it was getting right around 30 mpg (really good considering where I live). And had power to spare (maybe a wee bit too much for a stock lower end).

I learned a valuable lesson here too. This is the first time I have ever put an engine in a vehicle without at least freshening it up and it bit me in the ass. Likely if I had checked the bearings I would have replaced the main cap and rod bolts and maybe this would not have happened. Or maybe it was making more power then I thought and it still would have happened but you know what they say about hindsight...

There's my update and my wallet becomes thinner.

Jaysin
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
wow that sucks!.... but i kinda doubt the extra horses caused the failure...lots of high horse AHU's running around with the stock tty cap bolts and not failing like that ... perhaps someone pulled that cap for an inspection and wrenched on the bolts with ungodly impact wrench torque ?....
 

410onefour

Veteran Member
Joined
Sep 28, 2008
Location
Jasper alberta Canada
TDI
2003 jetta tdi wagon, 1991 toyota mtdi
I've seen this exact failure twice on the AAZ blocks which is almost identical to the AHU block. One engine was converted to an MTDI and the other one was a bone stock AAZ. Funny enough, both engines broke the number 2 main cap and bolts.

Sorry to hear though. I agree with jimbote that the failure isn't related to the power increase over stock.
 

vanbcguy

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Joined
Feb 22, 2013
Location
Vancouver, BC
TDI
'93 Passat - AHU mTDI with GTB1756VK
The early AAZ engines came with shorter main bolts from what I recall... So that may not directly translate to the AHU.

I've seen some REALLY big power builds on the stock bottom end so likewise I don't think it is related to power level.
 

JaysinSpaceman

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Joined
Aug 5, 2008
Location
Skull County, Ca
TDI
Golf
Any thoughts on why the two main bolts broke then?

I don't know any history on this motor before I got it so it is possible that someone reused the bolts instead of replacing them or over torqued them when they had the cap off but there really isn't a way to tell that at this point.

410onefour,
I find it interesting that both of the failures of cap bolts that you saw were the number two cap. In doing some searching around the web I did find a few pictures and references to main bolt failures on the number two cap on AAZ, AHU and 1.8t blocks, which are all similar blocks.

In all my years of turning a wrench on stock and performance engines the highest rate of bolt failure has always been on the TTY fasteners (in particular on performance engines) and if I had realized that the mains on this engine were TTY before I installed it I would likely have changed them out before I installed it. Most of the TTY failures I have seen have been main or rod bolt failures but I have also seen several head bolt failures as well. The head bolt failures were all on boosted gasser engines.

Regardless whether the TTY bolts were the culprit or not the new motor is getting ARP fasteners on all critical points: mains, rods, and head. The bolts failed before the cap or block which tells me the bolts are the weak link, if the cap or block had broken out I would say the stock bolts are fine but that is not the case here.

I no wanty crank shaft fall out and get run'ed over.

Later,
Jaysin
 

JaysinSpaceman

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Skull County, Ca
TDI
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nnnnnnooooooooooooooooooo!!!
Yep! It happens.

But then this

What a bummer. New motor sounds pretty rad though :cool:

Now, sure it's kinda a downer to have to go back to driving my gasser 2wd Toyota and it's going to be hard on the wallet to do it but I get to build a tdi from scratch with a bunch of good parts to make it bullet proof and I will get to learn a lot. I already have learned a lot what with the previous I-shaft bearing failure and fix. Not to mention building the M-Tdi pump in the first place. And now every part of this truck will be new and I will know every part intimately.

"Everyday is a school day!" Gene Winfield

I still find it rather interesting that every main bolt failure I can find reference to on the web in the AAZ/AHU and 1.8t seem to be the #2 main cap. I haven't found an explanation for it but you can be sure I will be looking for it when I dissemble this motor. If anyone can shed some light on this I would love to hear you out.

Thanx,
Jaysin
 

410onefour

Veteran Member
Joined
Sep 28, 2008
Location
Jasper alberta Canada
TDI
2003 jetta tdi wagon, 1991 toyota mtdi
I don't get it either. The only conclusion I came to was the bolts on the number 2 main cap were either over torqued or under torqued from the factory. One good thing about this failure is the head usually survives. The last time it happened to me, the only reusable parts from the bottom end was 3 pistons and 3 rods.

If I were in your place right now, I would find a low mileage short block, do the intermediate bearings and some arp hardware for the mains and rods and call her good.
 

JaysinSpaceman

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Location
Skull County, Ca
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It gets even better.

You don't even need Magnaflux to see these cracks.















Hard to see but both #2 and #3 main cap bolt holes had cracks right through them.




To be honest I am not sure when this happened. A while back I had noticed some wetness on the side of the block but with the motor mount, alternator bracket and oil filter mount on the block there wasn't any way to see this. At the time I thought that it was the Oil filter mount leaking as it was definitely wet around it but now I am wondering...

So, what came first the chicken or the egg. There is a spot on the other side of the crankcase where something wanged it, likely after the main let go. But the other side of the block is much thinner then the cracked side and I would think that if it hit hard enough to do this damage then it would have windowed the block where the impact was.

Even some of you are telling me that at the kind of smoke level I am at I don't even need main studs, having seen this I am thinking that a main girdle is in order. I may not be making 200 hp or even 175 hp but the engine is in a truck that weighs near 1000 lbs more then the stock car it came out of. I was about a week from running it on the dyno to find out just what kind of power I was making when this happened. I am thinking that building a bullet proof short block is at the top of the list. Hell, it's only money.

I will be taking a sledge hammer to it to finish the job and see if there is any tell-tale signs that there was a casting flaw or rust in the fracture that would tell me how long it's been broken. Information is king.

Someone once said I could likely break an iron ball, well I came close, I broke an iron block.

Time to start making the wallet lighter.

Thanx,
Jaysin
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
your truck is grocery bag in the wind compared to a syncro westy, or a plain westy for that matter.... tons of those running around with modded tdi mills on stock lowers with zero issues....
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
I don't get it either. The only conclusion I came to was the bolts on the number 2 main cap were either over torqued or under torqued from the factory. One good thing about this failure is the head usually survives. The last time it happened to me, the only reusable parts from the bottom end was 3 pistons and 3 rods.

If I were in your place right now, I would find a low mileage short block, do the intermediate bearings and some arp hardware for the mains and rods and call her good.
this ^^ is what I thought too ... can you extract what's left of the bolts from the number two main webbing? maybe a closer inspection will reveal something ....
 

410onefour

Veteran Member
Joined
Sep 28, 2008
Location
Jasper alberta Canada
TDI
2003 jetta tdi wagon, 1991 toyota mtdi
Before you take the#2 main bolt ends out of the block, try and reassemble that main. Make sure you match up the right bolt to its matching bolt end in the block. I looked at your original pictures of the carnage and it looks like the bolts came loose and then broke. Worth having a look at anyway.

I've also wondered how many failures are caused by a mechanic checking the mains? For some reason the number 2 main might be the one that's most likely to get checked. Bolts get reused or improperly torqued and there's the failure point.
 
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libbybapa

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'83 AHU mTDI high top Vanagon, '84 AHU mTDI pop top Vanagon, '85 Franken-mTDI Adventurewagen Vanagon, '91 Vanagon ALH mTDI tin top auto, '02 Jetta eTDI Wagon, '02 Jetta eTDI Sedan
your truck is grocery bag in the wind compared to a syncro westy, or a plain westy for that matter.... tons of those running around with modded tdi mills on stock lowers with zero issues....
In vanagons I know of one broken crank and two with main bearing issues not as extreme as this but probably would have been if run longer.
 

JaysinSpaceman

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Updates are going slowly right now.

I am still in need of an answer for the block failure but I am thinking that I may never get one as sometimes it is near impossible to discern the originator in a catastrophic failure like this. There is missing info that I may never know, like just how much power/torque this engine was making just before it went pop. I was a week or so from throwing the truck on the dyno unfortunately. The best I can do is throw it on the dyno once it's rebuilt which might give me a rough idea but that is about all. Was the engine from a vehicle that died a horrible death in a head on accident? How had the previous owner treated it? Was it dropped in shipping? Etc...

Concerning how much the juice was turned up on this motor and whether power was a factor... The injector pump has a 2mm larger then stock pump piston (12mm vs. 10mm 44% bigger), the injectors that I am running are capable of flowing 103% more fuel then the stock nozzles and supporting 210+HP and the boost was running at 22 psi (starting at 1600rpm) vs. 12-14 psi max stock. So yes it was turned up just a bit. A seat of the pants guess is torque in the neighborhood of 300-350 ft/lbs. All that said I have been told that it "should" have been fine with my modifications.

I now have another block (this one will get throughly checked out) and one of the things that I am going to look at if the possibility of core shift in the old block that might have made that side thinner then it should have been. I have also, since my last posts, finished off the block with a hammer and I have to say it didn't take much effort (I did it at the bay area GTG). At the rear of the block the casting was held together by just over a 1/2 inch of material and the front was only slightly better with only 2 inches still intact. The whole block was shattered. Unfortunately it didn't tell my semi-trained eye a whole bunch more. Then I happened to notice the most telling clue yet, number 3 main web was broken through the main bolt hole on that side of the block and the main cap was considerably fretted on the outside of the crack, which I think, tells me that the block had been broken for a while (hundreds or thousands of miles?) before I caught it, ie. the #2 main cap departed the block.

Pictures of the now finished block and below that the fretting visible on the #3 main cap parting line.

Sorry about the blurriness of this first picture.






Matching #3 Cap fretting.


Just the cap.

Close up


#3 block fretting. Just the block.


Maybe this gives someone more insight that they'd like to share.

I am working on the main girdle design for the new block. I am getting it all sorted and once I have the design finalized then I will have some 1/2" plate waterjet cut and surfaced. Is a girdle overkill? Most likely, but I am not going to rebuild this engine without making sure that this doesn't happen again. One way or another the new motor is going to be stronger then the old and I (and my old engine machine shop instructor) think the girdle will help to solidify the bottom of the block, at least helping the strength and minimizing flexing.

The head is currently being rebuilt at Frank's TDI and while getting rebuilt it is also getting the intake and exhaust ports cleaned up by Frank as well. A little porting can't hurt, especially on the tiny exhaust ports.

Thanx again for all the input,
Jaysin
 
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