1986 MK2 Golf 1.6na with air/con to TDI (ALH) conversion build thread / scratch pad

[rotaecho]

Project still moving. My pup passed away 09/23 which slowed me down and some other life **** happened. Started to revisit this last weekend.

Still grabbing parts. I thought the MK3 pedal cluster would work, but not as well as what research tells me. I got a B4 passat pedal cluster arriving from Jimmy (@jimbote ). And I got a lead on the brake-booster/clutch master bracket, hopefully purchase that this week. I think those are the last two B4 Passat parts I needed along with the MK3 Jetta TDI parts I have to least bolt the subframe and suspension to get ready for the engine.

Still planning the CE2 conversion. I have a 1992 16 valve Golf CE2 whole car harness, I'm hoping that'll help swap over to the MK2 Golf easier.

Baby steps, hopefully some real progress in a few months.

 

[jhax]

With the CE2 conversion you may need to convert to a new style dash board to accomodate the HVAC/Radio/Instrument cluster surround as the older US electrical cars had a different setup and the plugs were all different. I repinned my OG diesel cluster harness for CE2 But the plastic surround for all of that is different between >86 and <86

 

[rotaecho]

Yep, I came across that when going over it all. I ordered the replacement lower panels that go infront of the AC with the stock top dash.

We'll see though if it works out.

I just pulled the carpet yesterday, going to be ripping out the old inside harness next day or so.

With the CE2 conversion you may need to convert to a new style dash board to accomodate the HVAC/Radio/Instrument cluster surround as the older US electrical cars had a different setup and the plugs were all different. I repinned my OG diesel cluster harness for CE2 But the plastic surround for all of that is different between >86 and <86

 

[zipitie.nz]

nice effort so far. would love to see more pictures, sorry to hear about your pup also

On my conversion I stuck with CE1 fusebox to power the Mk4 looming

but converted a CE2 petrol clocks to run as the 1.6 na diesel cluster was horrid in my car. and had no tacho

I am working to implement AC on mine also but haven’t been able to nail it down yet. Small bumpers does not give you a-lot of real estate behind the bumper especially with a intercooler to accommodate

 

[rotaecho]

Its slowly coming along, just other priorities lately. I am doing photos and videos, I hope to have them uploaded when I get further along and go through them and add them to the website and this thread.

 

[rotaecho]

So, not *really* related to the engine yet.

I'm done spraying the firewall / engine bay / front floor pans of sound deadener (spray), and new base coat, but needs a few more base coat sprays and clears done.

Also doing the rear floor pans and back as well here. It's all stripped down.

Verified / Stripped (starter interlock relay, etc.) and rewrapped the MK2 16V GTI 92 CE2 interior, steering stalk, and fuel tank harnesses.

I realized my donor GTI front-end harness was a butcher job so obtained one from a friends B4 Passat TDI he was parting out as also a spare CTN TDI transaxle (= I have a B4 ALH done engine harness already.

I think that takes care of most of my CE2 harnesses except Misc **** and how to approach the A/C . . .

What little info I can find, using MK3 controls require a MK3 dash; not going that route too much effort.

I plan to stick with the MK2 AC control panel and dash layout.

I have a CE2 A/C harness from a 91' G60 with the N plug (green single 6pin) and relays, as also a B3 Passat A/C harness with the N plug as well.

From what I'm told the B3 Passat has more safety's, but works same as the G60 harness (OFF/ON). I don't have a Bentley for those only A2 & MK3/MK4.

I do plan to use a B3 Passat rad fan harness adapted plugs for slim-line fans, so it may make more sense to stay with the B3 AC harness.

Still plan to use the MK3 evaporator, condensor, recdryer, and possibly lines (or make new not opposed after watching a few videos).

I'm still unclear on which compressor I should use; MK3, MK4 or a fixed-compressor for the MK2, but then I read late Corrado/B3 had variable compressors. I know S&P as others make adaptors for older MK2/Corrado lines can connect to a MK3 AC compressor.

I also read (maybe here), that the MK3 compressor is variable like the MK4 and you can remove a valve to make it a fixed compressor suitable for a MK2 setup. Again, I haven't got a lot of solid info here, still in the research phase.

Which brings my next question;

Variable vs Fixed A/C compressors, but would the new AC harness allow for proper function of a variable compressor? Or is that determined a nother way; via the control unit? Or by use of the relays? I rather not use the MK3/MK4 FCM as it's overpriced, buggy (when not OEM), and overly cumbersome I felt. When I worked with it on the few cars I fixed issues on it; the diag was easy, unit costs and proprietary lost my interest that route.

I can't "tell"a difference other than the P/N, but I got a later CE2 AC slider control panel which is supposedly required for the CE2 swap as well; not sure if any relation to what compressor requirement.

vwvortex and clubgti have some info (dated), but not many that had to start from the 86 USA and decided to keep the AC. Most just dumped the AC it appears. Or the few that kept AC used a MK2 setup with adapted MK3 / R134a connector ends onto their existing lines; and flushed.

I hope to get done in the next few weeks.

* Have the bay cleaned up rest of way with the base coat/clear and the MK3 cross member installed with the MK2 control arms.

* Install the MK3 suspension and tires to land on if jacks get moved haha. Just makes me nervous.

* Install CE2 fusebox bracket & run the interior harness.

* I got a hydro clutch brake booster bracket for the TDI trans, and cut / marked / mounted the new spot for that. So, that'll get mounted when subframe goes up.

I haen't done **** to the engine, but I figure the "biggest" parts in an engine conversion is all the prep work for installing the engine and driving off

 

[rotaecho]

In addition, I'm on the fence about what to do about the steering rack.

People keep giving me horror stories about MK2-MK4 power-steering racks blowing out and needing repairs often.

Others say to loop the MK3 power-steering rack.

Then others say to use the MK2 1.6na manual rack.

I currently daily a 1982 Westfalia Hightop with a mTDI, with no power-steering.

But the geometry could be way different when sitting.

Any personal or professional experience her is welcome.

 

[oilhammer]

The only steering rack I have ever replaced in any of my Volkswagens was the one in my 1982 Audi 5000, and it had some ~200k miles and 15 years of use on it by then.

I've never once replaced any steering racks on any A2 cars, and I've only ever even seen a handful of A1s that had them (of course, if you count the Scirocco, then I've seen a few more... but never a bad one).

I can count on one hand how many A3 steering racks I've replaced.

I've seen maybe about 10 total A4 steering racks.

Given how many of these cars I have seen over the years, I'd say power steering racks failing are not a big thing. The ones I have replaced were all pretty high mileage.... the last one I did was a 2005 BEW Jetta with 430k miles. I'd say that rack did good.

I've seen FAR more Hondas, Fords, Toyotas, GM, Mazda, and of course the King Crap of all power steering racks, the Chrysler [insert anything here from the '80s and '90s] models.

The Transporters, as well as most other models, place the tie rod end at a different spot on the spindle if they have power steering. Often you'll see the obvious extra bit in the casting when they place the hole further in on power steering equipped models. So there is other differences besides just with or without an assisted rack. Transporters of course also got a bigger steering wheel with no power.

With the proper 185-R14-C tires, I never found the manual rack T3s to be bad to drive at all.

 

[rotaecho]

I'll plan to use the MK3 power steering rack and hook it up to he ALH engine when done.

Thanks for your feedback!

The only steering rack I have ever replaced in any of my Volkswagens was the one in my 1982 Audi 5000, and it had some ~200k miles and 15 years of use on it by then.

I've never once replaced any steering racks on any A2 cars, and I've only ever even seen a handful of A1s that had them (of course, if you count the Scirocco, then I've seen a few more... but never a bad one).

I can count on one hand how many A3 steering racks I've replaced.

I've seen maybe about 10 total A4 steering racks.

Given how many of these cars I have seen over the years, I'd say power steering racks failing are not a big thing. The ones I have replaced were all pretty high mileage.... the last one I did was a 2005 BEW Jetta with 430k miles. I'd say that rack did good.

I've seen FAR more Hondas, Fords, Toyotas, GM, Mazda, and of course the King Crap of all power steering racks, the Chrysler [insert anything here from the '80s and '90s] models.

The Transporters, as well as most other models, place the tie rod end at a different spot on the spindle if they have power steering. Often you'll see the obvious extra bit in the casting when they place the hole further in on power steering equipped models. So there is other differences besides just with or without an assisted rack. Transporters of course also got a bigger steering wheel with no power.

With the proper 185-R14-C tires, I never found the manual rack T3s to be bad to drive at all.

 

[rotaecho]

@oilhammer by chance, in your VW years of MK3/MK4 have you replaced a lot of FCMs?

I've replaced two failed in two MK4s, and one of the replacements (not OEM) was DOA, so I found a used one. I do have that whole MK3 harness that has a FCM which I could use.

Maybe I just had a bad experience. I did like the support matrix for the FCMs when I was diagnosing my friends A/C problems.

I think the B3 Passat AC management or the MK3 FCM are probably my two best choices.

 

[rotaecho]

I know I can swap the MK3 HVAC evaporator into the MK2 housing and have the proper fittings for the evaporator. But is there a benefit to the MK3 HVAC system being swapped completely?

I got a few posts out mostly in RHD UK, but a few in USA. . .

I know the MK2 HVAC is vacuum controlled where the MK3 is cable controlled for the control system.

I have read a lot of information in the UK (RHD) on this, but fitment is different so I can't get a determination on any successful LHD installs.

One forum here: https://www.vwgolfmk2.co.uk/clubforum/index.php?topic=158.15 tried to hook the MK3 cables to the MK2 AC/Climate control levers in the control panel and it worked, just opposite direction. It's mentioned here in https://clubgti.com/forums/index.php?threads/mk3-air-con-in-a-mk2.264574/ (UK based again) but no verification in LHD. They said in RHD it was opposite, so in my mind in LHD it should be proper?

I'm trying to get verification still if this is possible. If so, I can dump the vacuum system and go cable driven. The HVAC should also have all the proper connectors I'd need that maybe newer too.

Lil by little

-Will

 

[rotaecho]

So, this is a very good read about the R12 to R134 Fixed vs Variable compressors on a G60. Very applicable for this setup I believe.

This really helped me. https://www.vwvortex.com/threads/th...xed-or-variable-displacement-debacle.6111937/

I think the real two questions left are:

First, the HVAC unit swap as a whole or as sections with the cables instead of vacuum control mentioned in previous post.

Second, decision how to control it. Likely use a mk3 golf ac and recirc button, they fit mk2 dash but vertical.

Then what to do with harness. I guess I need to do some thinking of what provides best placement and support.

92 B3 A/C Harness from a

91 Corrado A/C Harness

MK3 FCM adapted

 

[rotaecho]

Okay, I've got the MK2 & MK3 HVAC box side by side to help visualize and understand things better.

So, looks like the MK3 heater side of the HVAC box doesn't fit the MK2 (which was discussed online), so the MK2 heater side needs to stay the same.

As far as fan control, I'm leaning towards the 1991 G60 Corrado / early B3 1992 CE2 A/C N harnesses that use relays and no FCM.

I was looking at the MK3/MK4 FCM, but I think it's more bloat and proprietary than I want to go. I've diag'd the FCM on two MK4's that have failed. The support/diag matrix is indepth, BUT when you need to replace the FCM . . . that's the "real" fun. For all the MK3 HVAC stuff I have and harness, I looked at the MK3 FCM since I have one here from a parts 98 Jetta TDI. Just to see how easy to obtain like the MK4 (which was same ordeal).

You can find aftermarket ones betwen $40-150, and an OEM for $250-300 new online and at local FLAPS.

All options for the FCM would take a week to arrive, so if the FCM died, I'm a week down and from my research (as personal experience), the aftermarket FCM's are all hit and miss. The most popular URO version I got for my friends MK4 was defective on arrival and caused many more unneeded debugging to determine that. The OEM is the only real way to go. I found a used one on ebay, ordered it, and tah-dah! Magic, all working.

In contrast, you can get the relays all day long at any FLAP and amazon next day for like $10 on the G60 Corrado / early B3 Passat AC control setups.

Okay, so I've determined how the A/C is controlled using the MK2 dash & slider control panel.

The question is;

Is there a benefit in switching the MK3 HVAC AC side of housing instead of just a MK3/B4 evaporator into the MK2 HVAC AC side of the box?

I know that the MK2 is ALL vacuum based in its control. And the B4/MK3/MK4 are all cable based.

That said, if the MK3 A/C side of the HVAC box is desired, and using the relay controls not the FCM is done; is this a workable combination?

If so, any gottchas or tidbits you foresee?

Sorry for any repeated/rehashed thoughts/etc. It just hasn't been too clear in the forums (to me) and I want to get the AC right the first time; seems like the harder isue in the conversion than other aspects to me.