Author Topic: MKIV TDI swap and MKII mounts - problems. Help needed (Read 5485 times)

dubCanuck1 · « **on:** January 24, 2006, 03:10:18 am »

Hi all,

I'm running into some serious clearance issues with the rear engine mount and the vacuum diaphragm on my MKIV TDI swap into a MKII shell. I've cut away some of both the console and the mount to allow the turbo to fit and the vacuum diaphragm to clear the motor mount.

It's extremely tight and the mount would knock against the diaphragm, likely damaging it. Has anyone done this with a MKIII subframe and mounts with a MKIV TDI swap? I'd like to see pictures.

Unfortunately, the 1.8T swaps out there aren't of much help as they only have the exhaust manifold on the rear of the engine and just have to reroute the I/C piping to fix the problem. See below for my quandry.

Actually, if someone has a MKIII 4 cyl or VR6 rear mount picture from the top pointing down at the mount itself, that would be great. I know I'll have to cutaway some of it, but if the subframe mount is smaller, it may just do the trick.

X@V · « **Reply #1 on:** January 26, 2006, 01:47:55 pm »

Use a grinder :wink:

vwmike · « **Reply #2 on:** January 26, 2006, 04:05:36 pm »

I have a MK3 subframe in my 88 Jetta.

Here is what the mounts look like:

And what the subframe in the mk3 looks like.

I don't know if those will help you. I could probably take some pictures of my car though I'm not sure you'd be able to see anything back there.

malone · « **Reply #3 on:** January 26, 2006, 04:20:46 pm »

I think there's a clearance issue with the VNT on the MKIII rear mount too, but I'm not 100% sure. I have seen a '97 Passat with a MKIV TDI swap in progress (now finished) and its rear mount had to be modified. IIRC the mount was simply grinded and then rewelded for strength.

dubCanuck1 · « **Reply #4 on:** January 26, 2006, 09:53:16 pm »

Thanks Mark,

I suspected that. I think my best bet for the time being is to pickup a MKII Hydro Mount for a 16V. My major problem with the stock MKII mount is that not only the console, but the mount have to be modified (as per my pics above). With the Hydro mount, I think the space just below the mounting plate of the hydro mount will allow for the clearance I'm looking for. I can also modify the plate on the top to allow enough clearance.

DieselMonkey · « **Reply #5 on:** January 28, 2006, 03:50:00 pm »

Hi,

I've got a similar problem in my mk3 engine bay. The mk3 isnt free of this problem but maybe you can modify the subframe and mounts of a mk3 easier and better than a mk2.

What i'm thinking of doing is cutting the steel body that the engine mount slides down into and re-welding it at a different angle. As you know the engine needs to move about 4 inches back when under load.

I dont think this is a serious problem, the wiring, ECU, power output, tuning and the cost are worrying me more than getting the hardware into the engine bay.

DM

therabbittree · « **Reply #6 on:** February 02, 2006, 08:05:52 am »

mummn i'm debating trying to swap a mk4 engine into my '95 passat glx wagon..but use the wiring and ecu from a '98 jetta TDI...with kkk24 turbo and manifold..i was wondering on the motor mount fit..i hope it would work.. as i have afew parts mk4 tdi engines to make one good one out of...and other stuff would need a custom chipto work right im sure..but it would be nice..
later
Deo

dubCanuck1 · « **Reply #7 on:** February 02, 2006, 02:11:33 pm »

The motor mounts for the MKII work just fine on a MKIV engine. If you are using the 02J tranny that came with the MKIV TDI, you will have to get the starter bolts for the Audi RS6 as they are 160 mm in length and are long enough to go through the stock front mount.

The back of the MKIV engine has the castings for the MKII mount. That will bolt straight up.

For the tranny, get the console and support that are used for the 02A or 02C trannies. This will allow you to mount the engine on completely stock hardware.

Apparently, the MKIII TDI front mount is a better match for the 02J housing, giving it the 3rd hole to bolt into.

The only problems us MKIV swappers have is with the turbo setup. The stock VNT15 and manifold interfere with the rear MKII mount. You can get around this in a couple ways...

1. Use the MKIV mounts (requires welding skills and custom length drive shafts as the engine doesn't sit in the same orientation as the MKII)
2. Use MKII mounts and cut the hell out of them and clock the turob outlet up. This is what we're all messing with.
3. Use a different manifold and turbo. This (Malone can verify) usually requires a little "hammer massage" of the firewall, but other than that, resolves the mount issues.

So in summary, if you can mount the exhaust manifold from a MKIII TDI and are using the turbo from that same TDI on a MKIV engine, you should have little if any problems, seeing as the MKIII TDI sat on pretty much the same mounts (positioning wise) as the MKII.

Just noticed you're doing it for a MKIII anyway. You should be fine.

therabbittree · « **Reply #8 on:** February 02, 2006, 06:08:19 pm »

mummn i have a '98 jetta tdi trans here..but a mk4 trans would be nice especailly if i when and swaped a 6spd or lower final drive in with eth low lower 5th gear fro soem low crusiing rpms..neat i didn't know teh mk11 stuff would bolt right up tot the mk4 tdi engine..that looks liek my solution..as fro turbos i have avnt 25 from dodge that i could do or a kk24 ..debating ..obviously i'd be doing some custom ecu or chip work to the fa '98 jetta ecu..rocket chip..hehe....i guess that will be my summer project ..as soon as the mech tdi caddy is done and then my kubota diesl into economy tractor swap is done then work on teh passta glx mk4 tdi swap...cool thanks for the info.
deo

dubCanuck1 · « **Reply #9 on:** February 03, 2006, 04:07:27 am »

OK, some more work and I decided to put that gray matter to the test to try to resolve the motor mounts problem. But first the pics.

I "convinced" the rear mount to allow me clearance. After all was said and done, there was about 1/4" clearance for the vacuum diaphragm of the turbo.

A little hammer work to clear more space....

Here's the clearance in the end...Pretty tight.

Ah, so here's my grand scheme that should work, if my geometry's correct. The pictures are hand drawn, but you should get the idea.
Now....Block and head are on the right side. Up is up. You're looking from the passenger side.

After....If this works, I think it would actually be easier to make the diaphragm point up. The lever would be more flattened (2x the angle of the one shown). With the extension too, it could be positioned above the EGR flange, even using the bolts from the flange for mounting.

If this hair-brained scheme works, I'll be able to use an unmolested rear motor mount to support my carved rear console.

Larger versions of the pictures are available here:
http://www.canadubs.com/images/large/DSC00613.jpg
http://www.canadubs.com/images/large/DSC00614.jpg

therabbittree · « **Reply #10 on:** February 03, 2006, 09:41:13 am »

do you have acces to a welder?..if so maybe make a new rear engine block side mount...ie support the engine in it the location you need and make a new rear back mount and if needed modify the sub frame mount .. you could use the stock rubber mount..... just an idea..as it seems to be a pain and rear tight in there if you decide to swap turbos or have to pull in int he car it might be apain..
just a thought
Deo