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1977 924 OBD1 AAA 2.8 VR6 Completed Transplant Thread

 
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Wasserg  



Joined: 13 Sep 2020
Posts: 8
Location: Alberta, Canada

PostPosted: Sun Sep 13, 2020 11:51 am    Post subject: 1977 924 OBD1 AAA 2.8 VR6 Completed Transplant Thread Reply with quote

Howdy folks,

My name is Greg and I am a bloke out of Alberta, Canada who has stuffed a 2.8 VR6 in to a 77' 924. I will not mention the 5 speed dogleg transmission conversion and other minor mods in this thread and primarily focus on the swap. I have attempted to post a build thread some years ago on to the 924 owners club forum, however my attention span is awful so I totally abandoned that until recently I have finally "completed" the project and moved into the troubleshooting stage.

To preface, this is a rat rod build. I have bought the car with this very unique paint damage caused by mis-matched paint and primer brand in the late 80's since no one wanted to rescue it and now it lives in my garage scaring passerby's. Here it is. Der Grauel. The Abomination!























Please note, I am just a deranged university student and by no means a purist. This is a proof of concept build and does not reflect my neglect for my personal safety due to the amount of metal epoxy used in this project.

Notable fabricated components and adjustments.
-Heatercore delete, firewall rebuild to accommodate starter and rear facing thermostat
-Notched subframe (the 924S and 944 might not require this)
-Extended steering rack
-New engine mount points around the shock towers on the frame rail
-Radiator is out of a 2000's something mercedes kompressor that fits PERFECTLY between the frame rails with some cutting.
-Cut up O2A transmission into bellhousing with a "custom" plate adapter.
-Custom ordered VR6 clutch that was resplined to accept the 924 torque tube.
-Throttle body relocation in order to clear strut tower.
-Custom simplified OBD1 wiring harness for engine stand operation.

Current issues:
-Clutch does not disengage all the way and drags a bit in neutral probably due to the difference in reservoir sizes of VR6 slave / my ghetto hydraulic master. I am bleeding it again to see if it will fix it. Naturally the motor has not started due to this.

Possible issues:
-Oil pressure to VR6
-Untested coolant routing courtesy of yours truly

Please pile in questions ill try to answer them in bulk. You may have seen this car around with twin weber 40's and on the cover of the 924 owners club magazine I was directed to post this build here since apparently this forum isnt dead yet haha. Cheers lads![/img]
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1977 Audi 5 Speed Dogleg OBD1 AAA 2.8 VR6 Swap
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Golten951  



Joined: 14 Jan 2017
Posts: 89
Location: Edwards CA

PostPosted: Mon Sep 14, 2020 3:19 am    Post subject: Fun! Reply with quote

This looks like a lot of fun! Very glad to see a VR6 engine in one of these chassis. It is a neat engine. Seeing where the starter sticks out and how far back you wanted the engine, I completely understand the firewall cutting. Did the same for my Audi V8 swap. Have you considered moving the intake air filter from behind the radiator to a bit cooler air Or re-purposing a Airbox?

For the clutch, Could be air in the system. you have a pressure or Vacuum bleeder to help?

I do hope the Oiling is good and should be good on the coolant.

There are still several of us on here, Glad you posted your neat 924!
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Wasserg  



Joined: 13 Sep 2020
Posts: 8
Location: Alberta, Canada

PostPosted: Mon Sep 14, 2020 3:48 am    Post subject: Re: Fun! Reply with quote

Golten951 wrote:
This looks like a lot of fun! Very glad to see a VR6 engine in one of these chassis. It is a neat engine. Seeing where the starter sticks out and how far back you wanted the engine, I completely understand the firewall cutting. Did the same for my Audi V8 swap. Have you considered moving the intake air filter from behind the radiator to a bit cooler air Or re-purposing a Airbox?

For the clutch, Could be air in the system. you have a pressure or Vacuum bleeder to help?

I do hope the Oiling is good and should be good on the coolant.

There are still several of us on here, Glad you posted your neat 924!


Hey! Thanks for the reply. Audi V8?! Awesome! 4.2?

Today is the clutch bleed day so we will see how it goes. The engine sat for a while and even after lubing up the crank bearings it stops turning by hand after assembly in about a day. I did rebuild it so I'm sure it will fire up just needs a nice tow with a clutch drop to get things moving.

In regards to the air filter I am kind of winging it at the moment since I just want to make sure it starts before I optimize the system. The engine bay picture is a bit dated since the coolant reservoir is missing along with all the piping that ended up there post completion. I definitely will be re doing the oil pan or going dry sump as there's a minor leak at the rear near the bellhousing and would require a complete pull to remedy & I have no will power to do that before winter unless it's absolutely critical.
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Wasserg  



Joined: 13 Sep 2020
Posts: 8
Location: Alberta, Canada

PostPosted: Tue Sep 15, 2020 1:25 am    Post subject: Update 1 Reply with quote

Update 1

Master cylinder is probably shot or has bad seals, the clutch pedal sometimes has a delay between coming back up and after two bleeds it still drags. I will look into this later as more issues came up during engine break in.

Engine got broken in, dumped the clutch in third while being towed and it turned over. Very good oil pressure and sounds great even though its not firing! Tried to test ignition trigger to see if it will actually start but i think i lack spark. The relays were going bananas but the injectors and fuel pump were firing as far as I know.

OEM fuel line ruptured under EFI psi pump so thats a problem and perhaps I smelled that more than the injectors firing haha. Starter clicked and engaged but did not spin, I did see I have 11.5v but that should be good for something. Hopefully the starter isnt shot but without pullin the motor i cannot fix it so I think I will try to tow start the car to make sure the engine runs before taking it apart to remedy that.
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Golten951  



Joined: 14 Jan 2017
Posts: 89
Location: Edwards CA

PostPosted: Tue Sep 15, 2020 9:04 am    Post subject: Reply with quote

You are welcome man, Cool to see a VR6.
I have my thread on here for my 4.2L swap if you want to check it out.

I can understand the Filter placement stuff. Once up and going will have more time to play with it.

Ahhh that would make sense on the clutch acting up. Would be worth getting a new one. Hmm could be worth checking the spacing from the throw out bearing to the pressure plate if possible.
I know if the throw out bearing is not engaging properly if will cause problems.

Super cool you got it to turn over and make good pressure that is important.
Check all your grounds for power relays. I know they can mess up some stuff for relays.

I know some relays can act up really bad if they voltage drops below 12 volts. can make stuff go really wonky. I do hope some of this helps out. really looking forward to seeing this car done.
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Wasserg  



Joined: 13 Sep 2020
Posts: 8
Location: Alberta, Canada

PostPosted: Mon Sep 28, 2020 2:36 pm    Post subject: Update 2 Reply with quote

Got around to getting some work done in order to charging her up before fire up test #3 with an actual battery charger. Replaced the popped fuel line from the previous attempt and got a new larger displacement master cylinder which should fix the dragging clutch problem. Brand new relays are in the mail so fingers crossed they will show up soon. Really hoping to sort the clutch issue out and hopefully the starter will actually turn instead of just engaging under proper 12v.

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Golten951  



Joined: 14 Jan 2017
Posts: 89
Location: Edwards CA

PostPosted: Wed Sep 30, 2020 4:29 am    Post subject: Reply with quote

Very good man. I am stoked for you to be able to legit drive this machine! I do hope that the Relays and master cylinder work out.
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Wasserg  



Joined: 13 Sep 2020
Posts: 8
Location: Alberta, Canada

PostPosted: Thu Oct 01, 2020 4:10 am    Post subject: Reply with quote

Update 3

Unfortunately the only good thing out of this test was the fact that the starter and relays behaved better under constant 12V. The new master cylinder produced worse results than the old master cylinder which is just bonkers. My only explanation is that I partially bench bled the slave before putting everything together so the running theory is that a lot of air got in while the master was getting swapped and it was impossible to get all of it out due to all the bends and what not.

The clutch behaved worse where i had to kick it multiple times for it to "disengage" or to basically depress enough to drag which made the test pull very awkward and stressful.

Current game plan is to hopefully remove the slave without taking apart the motor again and bench bleed it.
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Golten951  



Joined: 14 Jan 2017
Posts: 89
Location: Edwards CA

PostPosted: Tue Oct 13, 2020 5:04 am    Post subject: Reply with quote

Hey man, Hope you are getting stuff sorted out. I was out of town in the mountains for a bit so signal was spotty. Anything new?
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Wasserg  



Joined: 13 Sep 2020
Posts: 8
Location: Alberta, Canada

PostPosted: Wed Oct 14, 2020 6:42 am    Post subject: Update 3 Reply with quote

Unfortunately it looks like the motor might have to come out, clutch issues have not been resolved which leads me to believe that i did not account for the run-length of clutch splines on our driveshaft when deciding how much forward to push the engine. I am going to try to use some spacers to test my theory (between bellhousing and torque tube) to see if that will help. Worst case scenario i rip it out and make new engine mounts to account for the difference over the winter.

Additionally I think I will add an additional third engine mount towards the back of the motor just because loosing the bolts at the torque tube loaded the engine back a bit.

Only real bummer is that i wont get to drive it this year since its already starting to snow a bit here. I will keep y'all updated!
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Golten951  



Joined: 14 Jan 2017
Posts: 89
Location: Edwards CA

PostPosted: Wed Nov 11, 2020 8:38 am    Post subject: Reply with quote

Hey man. I do hope you can make some good progress over the winter. That does stink you will not be able to drive this year. But least will give you time to work through the bugs. Looking forward to seeing the results!!
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madislandguy  



Joined: 25 Nov 2009
Posts: 26
Location: Madeline Island, WI and Elburn IL

PostPosted: Thu Nov 12, 2020 1:51 pm    Post subject: Reply with quote

What is that front bumper from?
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Wasserg  



Joined: 13 Sep 2020
Posts: 8
Location: Alberta, Canada

PostPosted: Fri Nov 13, 2020 9:30 am    Post subject: Reply with quote

madislandguy wrote:
What is that front bumper from?


Hey! It is a cut in half and very much modified 240sx "pignose" bumper. I am also using a 240sx sylvia lip on the car.
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madislandguy  



Joined: 25 Nov 2009
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Location: Madeline Island, WI and Elburn IL

PostPosted: Sat Nov 14, 2020 3:07 pm    Post subject: Reply with quote

I thought I recognized it, just couldn't put my finger on it. It looks like it matches better than the stock bumper, that's for sure. Do you have any pictures from the modification process?
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Wasserg  



Joined: 13 Sep 2020
Posts: 8
Location: Alberta, Canada

PostPosted: Sun Nov 15, 2020 3:10 am    Post subject: Reply with quote

madislandguy wrote:
I thought I recognized it, just couldn't put my finger on it. It looks like it matches better than the stock bumper, that's for sure. Do you have any pictures from the modification process?


Unfortunately no as it was done a long time ago. The bumper is almost cut in half and tensioned on the bottom via two "struts" to the frame to keep shape, silicone inserts to better match the "sides" and some of the supporting cross sections in the openings were cut off and ground down. I can take some photos of the set up if you are interested when I have time and its not negative million outside haha.
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