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1980 Monaco Blue 1.8T engine swap

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Brian L.  

Joined: 10 Jul 2006
Posts: 126
Location: Buckley Washington, USA

PostPosted: Sat Mar 23, 2024 8:10 am    Post subject: 1980 Monaco Blue 1.8T engine swap Reply with quote

[My goal here is to share with others who are contemplating this swap so they can learn from my mistakes and since info. on the web is kind of spotty.]

I’ve owned my 1980 Monaco blue since 1987 (maybe even earlier than that) its been parked the last several years and probably needs a fuel injection rebuild, pumps, fuel distributor, injector lines, you name it. I’ve been thinking about a swap and decided this was the time to do it.

After a couple of years contemplating my VW/Audi 1.8T swap and gathering parts, I’m now about 3 months into the swap. I'm far enough that I'm past the point of no return so I decided it's time to post some content.

I'm kind of feeling my way along and I've seen a number of these conversions completed but with some variations. Some are 944/924S and the owner has a CNC milling machine for making an adapter plate but I figure I'm typical of a lot of you out there, I have some decent fabrication skills but I don't have a lathe or a mill, just a drill press, band saw, mig welder (and a tig that I haven't even used yet!) oh yes and a table saw more about that later but you get the idea.

My main inspiration comes from a couple of Brits who posted here but they posted more in depth on TIPEC (The Independent Porsche Enthusiasts Forum). Both of these are first gen. 924 cars and both swap were completed.

There are a number of others I found on the web but they are 924S models and/or they have little to no build documentation.

ENGINE: Audi/VW 1.8T This engine first appeared in the 1996 Audi A4 and a couple years later in the VW Passat. These cars were produced till 2005 with the 1.8T engine HOWEVER the early engines from 1996-2000 were the 058 engine, then sometime in 2000 there was a slight redesign, this changed to the 06A engine. The 058 engine is preferred because the oil pump is at the back of the motor, where the 06A is located at the front (chain driven) and interferes with the cross member. I believe the 06A could work with a redesigned cross member however starting out with a 058 engine just makes life simpler.

FYI: Motorwerks racing sells a custom crossmember but its for a 924S:


I’m sticking with the stock cross member but I did think about modifying it.
I'm using an older MK2 steel oil pan, the oil pan will have to be cut down some but bottom line is about 6 of one or a half dozen of the other.

Bell Housing:
As a lot of you have seen before the bell housing is cut from a front wheel drive VW transmission from a transverse mounted engine from a Jetta or Golf. Usually a O2J (5 speed) and can accommodate a 228mm clutch disc.
A O2M (6 speed) may work but I haven't looked into it but do know they can accept a 240mm clutch disc.
O2J (pictured below)

Just lately Lobb Ltd. in England has come out with a bell housing for the 1.8T swap but I know next to nothing about it but you can check it out here
Also check out their facebook page.

The worst part of this swap using the O2J is that the starter feeds in from the back of the bell housing and requires cutting the left side of the tunnel. Not a big deal for the Brits since that cuts into the passenger side of the tunnel but with us left hand drive folks it directly interferes (crowds) the gas pedal, far from ideal.



After thinking about a remedy for the starter location I decided a engine/bellhousing adapter was the best solution. However an adapter plate ½ inch. Thick would push the starter (mounts on the aft side of the bellhousing) and clutch fork a 1/2 inch. farther away from the clutch/flywheel. I thought about a spacer between the crank and flywheel. I was a little worried about the X factor, load, harmonics and cost. My solution was simple, just cut a ½ inch. Off the bellhousing. More on this later.

After studying different method by others settled making a plexiglass template of both the engine and bell housing.

Note the locating bushing that locates the bell housing to the engine. The black line is the vertical when the engine is in its stock configuration.

When I made the engine template I first used a 5/8 hole saw, that is .005 smaller that the locating bushings. Then I located the second bushing location after first drilling it undersize then taking up in size till I had a snug fit. Then I installed the main bearing cap (without the bearing) then scribed the circle from the end main bearing location. Then used my dividers to find the center of the crankshaft location and drilled a #40 (.098) hole there. Then I located the engine template on top of the bellhousing template and stacked them then both onto the bellhousing using the locating bushings and transferred the crank center location to the bellhousing template.

I then rotated the bellhousing template to locate the starter at the bottom, similar to the 924S/944. Note: line up the hole locations at the red arrow in the upper left. These two holes don't line up perfectly but at this location but get them as close as you can and others will line up and makes the most sense for others. (see below)

After transferring the hole locations to a 1/2 inch. plate of aluminum that will be the adapter plate. I first drilled the locations that have the locating bushings to 1/4 inch. and used my 1/4 inch. piloted 5/8 hole saw to cut about half way through the plate for installing alignment bushing that mate to the bell housing and same on the forward side of the plate to align to the engine block. (see below).

Okay now its time to subtract the 1/2 inch. that we gained with the adapter plate, here is where the table saw comes in. I after checking out the bellhousing it looks like I can remove a 1/2 inch. without much problem. So I put a 80 tooth carbide blade in my table saw and set it to a depth a little short of a 1/2 inch. (approx. .470). and proceeded to do numerous cuts across the face of the bell housing. (see below)

After a disc sander and a big vixen file I had the face of the bell housing all cleaned up.

Although I'm trying to keep the alignment as precise as possible its all a waste of time if the torque tube is mislocated. The way I've seen others do this is: engine/bell housing/spacer plate/2nd spacer plate with 3 alignment dowels. See the two pictures below.


dual plate

Admittedly adding an extra adapter plate only compounds things but I plan to do the torque tube alignment after the bell housing and both spacer plates have been installed. (more on that later).

Here is some more info. on the spacer plates. First of all the spacers meas. .75 inch. (1/2 and 1/4 inch. plates). .750 is the minimum, I measured it multiple times and its just enough by about .02 inch. (twenty thousandths).

Why not just one .75 thick spacer instead of two. Honestly, I didn't even think about it till after the fact but working with the two thinner plates is easier as far as locating holes and stepping them up in size. Also a .75 plate might create a clearance problem on the upper end and the trans. tunnel.

Here is the first spacer plate fastened to the bell housing.

Notice the right lower open hole. That location has a locating bushing. I drilled that one first, then back drilled the two upper locations. everything had a snug fit and the holes were just big enough to get the fasteners started. Then I back drilled the center hole for the drive shaft with a 45mm hole saw.

The second spacer plate (much smaller) I made a paper template and added a couple of ears to it for adding dowel pins. I'm missing a couple of photos for the second spacer plate sequence but after this next photo I will explain further.

Okay the second spacer place has a couple of tabs that are dowel pinned to spacer #1. Then I welded a couple of tabs onto the torque tube mounting flange. I had the engine mounted to a rolling cart and I had the torque tube mounted on blocks. At all 4 corners of the cart was a piece of all thread with an adjusting nut that I could raise or lower each end of the engine. When I had the drive shaft aligned to the pilot bearing in the crank where I could roll the cart back and fourth engaging and disengaging the drive shaft with no resistance I clamped the TT to the bell housing with a double hand screw wood clamp. Then I drilled the two dowel locations through the tabs I welded onto the TT and into the #2 spacer plate and drilled the 4 TT bolt locations.

This worked great because I did a test fit in the car and had no problem aligning the two together.

(stay tuned for the next installment)
1980 924 N.A. Monaco Blue owned since 1987
"Remember, sitting on your ass won't finish your project" -Puddins fab shop.
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Joined: 10 Dec 2006
Posts: 951
Location: Noosa Heads QLD Australia

PostPosted: Sun Mar 24, 2024 10:04 pm    Post subject: Reply with quote

Though not contemplating this swap, I'm watching with interest.
I commend you on your ingenuity and precise methodology.
80/81 932/8 ROW
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Posts: 138
Location: Hinckely Ohio

PostPosted: Mon Apr 08, 2024 5:56 am    Post subject: Reply with quote

very cool!
Bob Ward
80 9214 turbo, w 5.3 LS V8
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Brian L.  

Joined: 10 Jul 2006
Posts: 126
Location: Buckley Washington, USA

PostPosted: Tue Apr 09, 2024 9:54 am    Post subject: 1980 Monaco Blue 1.8T engine swap Post #2 Reply with quote

Okay, adding a few details to my first post.
There are (3) bolt locations that go through the adapter plate and into the engine block that interfere with the bell housing. (see photo below)

The bell housing can easily be notched for the two with the red arrows.

I used hex drive Allen bolts due to their smaller head size.
The one on the right I used a hole saw to gain some clearance. There is a lot of material there, so not a problem.
(see below)

The red arrow location on the left I had to do a simple notch although a csk. fastener could be used there. The only csk. fasteners I could get had large heads on them and didn't think they were ideal for the .50 inch plate thickness and edge margin (E.M.) issues. (see below)

The green arrow bolt location on the left gets totally covered with by the bell housing. I rounded the head of the bolt to gain a little bit of clearance.
I used a hole saw and a block of wood to guide the hole saw. (see below)

That is in the area between the lower two bolt locations. (see below)

You can see in this photo below where I
left some excess on the upper edge of the spacer plate #1.

I was really worried that with the bell housing rotated it would solve the starter interference problem just to create another somewhere else.
I did a test fit like this and there was a about a 1/8 of an inch clearance to the firewall/trans. tunnel. (see below).

I was relieved that it fit but decided to trim some more off the spacer plate and radius the upper edge of the bellhousing flanges. (see below)
Careful not to take too much off those flanges or you will break through the casting!

When you have a free floating motor that's not tied down to its mounts there is quite a bit of leeway to swing the torque tube up and down and side to side. I didn't take any measurements of the TT location prior to pulling the engine, so as far as up and down location I used photos I found of the shifter bolted to the shift rod linkage (the center of the bolt is about even with the lip where the shifter boot attaches). Also you have to take into consideration the
clearance between the engine/oil pan and the crossmember (more on that later).

As far as side to side, there is plenty of movement there also. I had a bit of delay because I didn't have my turbo yet, but after picking up a Ko4 turbo
(I think they are the same size externally as the stock Ko3 just a bigger compressor wheel) I put the head on including the exhaust manifold and turbocharger. Again I used the shifter as a guide to center up the motor.
I gave the turbo about a half inch clearance while looking at the engine
but I decided to notch the frame rail slightly just in case I ever go to a bigger turbo later on.
(looking down at the turbo from above)

After notching the frame rail.

Up next we get into the oil pan and motor mounts.
1980 924 N.A. Monaco Blue owned since 1987
"Remember, sitting on your ass won't finish your project" -Puddins fab shop.
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