S4s rolling restoration project

[snowrx]

I  put a 1st generation Stevens Alunox into my 85 G-car and I had thought the forward placement of the turbo was normal, but now am wondering about that...  It would certainly line up better with my fender exit if it was a bit farther back in the engine bay.

My turbo is supported from the bottom, so I don't have the support plate issue, but I went with a banjo bolt coolant line kit for clearance. I don't know if that would be available for the Garret port thread.

[Chillidoggy]

In my personal opinion, the included support bracket is unnecessary.  As it happens, mine fell off four years ago, and I never replaced it. There was no support originally, rather the non-issue was raised about by someone moaning there wasn’t enough support for the turbo, and Alunox caved in and supplied one to shut them up. Those with long memories will know who I’m talking about.

[Sparky]

Agreed, many thousands of miles and regular checks have demonstrated this to be a non-issue.

[sailorbob]

On 07/02/2021 at 12:40, Chillidoggy said:

But from my maintenance records, it seems I bought a pair of 3/8" x 3/8" NPT elbows and noted them as being for 'brass elbow for turbo coolant'. This does not categorically mean they're correct, but it's possible.

I have a note that the bearing housing coolant ports are a 3/8" - 18 NPT thread size.

[drdoom]

Careful with that thread terminology - NPT, or National Pipe Thread, are termed unlike straightforward fasteners. For instance a 3/8 NPT is not comparable in any way to a 3/8-16 bolt.

Cheers

[snowrx]

Yes, you are not going to find a 3/8 NPT banjo bolt option, as NPT is tapered.

Perhaps a NPT> 8AN adapter to a 90 degree hose fitting like the oil line might give some options.

[Chillidoggy]

I used a 3/8” NPT brass elbow, and I would definitely have used Loctite on the threads.

From memory, clearance is tight between the turbo body and hose tail end, but it will seal. I then used a new piece of silicone hose, ditching the original pink stuff.

[tomcattom]

I've actually ended up buying a 3/8 NPT banjo to 6-AN fitting plus some 6-AN to hose barb adapters because brass 3/8 NPT elbows like the type Ian used seem to be in short supply unless you wait a month for delivery by a slow boat from China and I'd rather not wait that long if possible.

Will see how I get on with the AN fittings but I have some brass elbows on the slow boat as a precaution if this doesn't work.

[sailorbob]

Is it the Torques Products Ltd. adapter that you've bought? If so I'd be interested to know how you find it as I've be curious about how it seals since they first came out. I'm surprised they don't make a barbed banjo too, maybe no one has asked them for one

[Chillidoggy]

I steered clear of banjo fittings as I couldn’t be sure how the internal restrictions would affect the flow of coolant, as opposed to the simple elbow.

 But that’s only my view, and is an unproven theory.

[tomcattom]

1 hour ago, sailorbob said:

Is it the Torques Products Ltd. adapter that you've bought? If so I'd be interested to know how you find it as I've be curious about how it seals since they first came out. I'm surprised they don't make a barbed banjo too, maybe no one has asked them for one

It is yes, and I'm intrigued too looking at the picture.

I figured it was worth a punt if it saves me a circa four week wait for the slow boat. Will share my findings when I've tried it. I've got a couple of extra days off work either side of this weekend and I've set myself the (overly ambitious?) target of getting the engine running again at the end of it.

[tomcattom]

On 09/02/2021 at 12:29, Chillidoggy said:

I steered clear of banjo fittings as I couldn’t be sure how the internal restrictions would affect the flow of coolant, as opposed to the simple elbow.

 But that’s only my view, and is an unproven theory.

It is/was a bit of a concern to me too, but I found plenty of banjo coolant feed kits for other turbos with different threads on the coolant ports (pretty much the same as shown in @snowrx post at this top of this page) so figured it was an acceptable option to at least try.

The fitting arrived today and the quality appears very nice on it, only time will tell if its a sound move to use it or not.

[snowrx]

One thing to watch for if you re-route any hoses is to avoid high points that could catch steam from the turbo after shut down. Mine would make boiling noises until I added an air bleed back to the header tank from the upper line.

[tomcattom]

Right side of the block has now been cleaned to about the same standard as the other side in readiness to fit the new thermostatic sandwich plate

BEFORE

AFTER

 

One of the two oil cooler hose unions was seriously stubborn and took quite a bit of effort to budge, but I did eventually get both undone and the original sandwich plate came out. I ran a tap down the threads on that rusty looking hose fitting before it went back on.

 

I had read on here that most people seem to use the Mocal sandwich plate but having seen talk of needing minor modifications to the hose adapters I think it was to make the filter seat properly I thought I'd try an alternative and went for the Setrab equivalent part.

• x1 Setrab HyperFlow Sandwich Adapter with 3/4" UNF filter adapter - 19-SPT76-34-180-22 (http://www.setrabusa.com/products/oilcontrol/oilfilteradapters/sandwich/index.html). The thermostat inside operates at 82°C.
• x2 Setrab ProLine adapter fittings M22x1.5 to 5/8" BSP - 22-M22BSP58-00 (http://www.setrabusa.com/products/connections/adapterfittings/index.html). Beware that the ProLine adapters while more expensive than others on the market do have rubber sealing rings for the adapter mating face.

Dimensionally its identical to the Mocal item but I was told by the supplier I used that they felt the casting on the Setrab part was of better quality than the Mocal one. I've not seen of handled a Mocal one to know if that is true, but the Setrab item looks like a quality item.

 

Sandwich plate installed nice and easily. I found it easier to install the plate with only inner hose adapter fitted first to make it easier to get spanners in to tighten the inner hose fitting up on that adapter. Then I fitted the second adapter and hose in situ. Both hoses were filled as best I could with fresh oil prior to connection too.

 

Part filled new filter installed and all buttoned up nicely without any fouling issues

[Paddock328]

Please forgive my ignorance! Why replace the sandwich plate?

[tomcattom]

With the OE sandwich plate there is no built in thermostat so the oil is constantly pumped through the oil coolers and therefore takes longer to warm up.

The Mocal/Setrab sandwich plates have a thermostat built in which only lets the oil through the coolers once it has reached 82 degrees so that the oil warms up quicker.

[tomcattom]

Courier just delivered my certificate of provenance (thanks @Bibs) and was surprised to learn I have the 16th S4s and the 1st one in Norfolk Mustard. I now also have confirmation what colour Lotus thinks my car should be despite the VIN sticker stating the colour is Azure Blue (B20) 😆

I didn't realise there were only 92 S4s's, I thought I read somewhere else that there were 360 of them 😕

[stephenwhyte]

A lot of firsts there, which is always pleasing to see. I can confirm that the 92 number is correct. Forty something made in ‘95 & 40 something in ‘96......it was a low volume variant (I was amazed when I found out my old one was 1 of only 2 Mica Yellow cars), which again is great to have. Clearly needs to be a keeper and worth investing money into👍👏👏

[Chillidoggy]

There were 367 S4s built between 1995 - 1996. By way of a comparison, mine was 136 and produced in October '95.

[Paddock328]

Thanks for the explanation, do you have an oil temperature gauge on the dash?

[tomcattom]

The S4s doesn't have an oil temperature gauge fitted as standard.

I'm currently in the middle of attempting to retrofit an oil temperature gauge from an earlier S4 model because the wiring for it does appear to still be present on my car. If my plan works I'll share my findings in a separate thread probably.

[tomcattom]

I've now reorganised the oil related sensors in the block to make space for the oil temperature sensor I want to fit. The low oil pressure switch is now in the T-piece with the oil pressure sensor so that the temperature sensor can go where the oil switch was previously.

The oil pressure sensor is very close to the under side of the throttle bodies but in the process of reorganising them I've discovered this isn't the correct pressure sensor for the gauge car so I've got the right part on order which will reduce the overall height. I still need to modify the wiring to accept the temperature sensor but I'll sort that in due course.

 

This is the Torques 3/8" NPT to 6-AN banjo installed into the port on the turbo with thread sealer. Seems well made, but quite how it will respond in this application is still unknown.

After a bit of playing around with various 6-AN to barb adapters I bought I settled on the 30 degree bend.

 

This is what is looks like with everything installed back on the car. Jury is out with regard to how it will respond to water under pressure, but I'll find out soon enough 😟

 

Oil feed and drain pipes hooked up to the turbo with fresh gaskets which means the car is oil tight again for the first time in about twelve months. I'm planning to fill and prime the system tomorrow 🤞

 

Here is a good illustration of how much further forward the turbo is sited when using the Alunox manifold. I'll have to adjust the exhaust tomorrow to get that to line up properly again.

[Chillidoggy]

Alignment looks the same as mine. I'm still thinking it needs to go 10mm further aft for correct alignment. It will seal, but make sure the mating faces are really clean, and a smear of exhaust paste wouldn't go amiss.

Did you find any wiring for an oil temperature sender hanging around the area? I looked at mine a few years ago, couldn't find any, and gave up at the thought of running a wire all the way to the dash board.

[tomcattom]

45 minutes ago, Chillidoggy said:

Did you find any wiring for an oil temperature sender hanging around the area? I looked at mine a few years ago, couldn't find any, and gave up at the thought of running a wire all the way to the dash board.

The wiring in the main part of the loom is present on my car Ian, its just the last foot at each end that appears to be missing. The oil temperature sensor wire is yellow/black and I've traced that up to the larger of the two big connectors behind the binnacle, I just need to reinstate the piece of wire from there to the gauge itself. In the engine bay there is a round three pin connector around/under the coolant header tank which is where the oil pressure sensor, pressure switch and oil termperature sensor wires all emerge from the loom. On mine the little subloom from this point to the sensors doesn't have the yellow/black wire, so I'll need to run that short length in too - provided the crimps I've got for the connectors are correct 🤞

Whether my findings will apply to all S4s or just the earlier cars I don't know.

[Chillidoggy]

1 hour ago, tomcattom said:

The wiring in the main part of the loom is present on my car Ian, its just the last foot at each end that appears to be missing. The oil temperature sensor wire is yellow/black and I've traced that up to the larger of the two big connectors behind the binnacle, I just need to reinstate the piece of wire from there to the gauge itself. In the engine bay there is a round three pin connector around/under the coolant header tank which is where the oil pressure sensor, pressure switch and oil termperature sensor wires all emerge from the loom. On mine the little subloom from this point to the sensors doesn't have the yellow/black wire, so I'll need to run that short length in too - provided the crimps I've got for the connectors are correct 🤞

Whether my findings will apply to all S4s or just the earlier cars I don't know.

I’ll have a butchers to see if I confirm your findings at the engine end, although I strongly suspect you’re right, and it’s the default wiring for the S4s. If I can find that plug, I might then have a look at removing the dreaded Rubik’s binnacle cover.