free hit
counters
Delanair rebuild/modification in '74 Elite - Interior/Exterior/Lights/Glass/ICE/HVAC & Other - The Lotus Forums Jump to content
EXCEL V8

Delanair rebuild/modification in '74 Elite

Recommended Posts

I've just started rebuilding the Delanair HVAC system from my 1974 Elite.  My plan is to simplify the vacuum system to allow for cable operation of the heater valve - the standard setup of the double-modulated vacuum control is a recipe for unreliability in my opinion.  Is anyone interested in seeing a photographic "blog" of this?  I'm a much more frequent poster on the Excel.net forum but I think there are more Elite/Eclat owners here who might be interested.  It's going to be a long process as this is just part of a complete rebuild!

Pete 

  • Like 1

Share this post


Link to post
Share on other sites
Upgrade today to remove Google ads and support TLF.

I'm following your progress over on Excel.net but would love to have a blog with pictures on here. Best thing about this site is that the images are hosted by the site so once uploaded they won;t be lost ala photobucket. :)


It's getting there......

Share this post


Link to post
Share on other sites

Yes, very interested. Have you looked at any other donor systems that may be suitable? I want to put AC in my Elite S2, and have the parts in a box for my S1. They were taken off, and weigh a LOT! Are you using a modern compressor?

Share this post


Link to post
Share on other sites
16 hours ago, Clive59 said:

Yes, very interested. Have you looked at any other donor systems that may be suitable? I want to put AC in my Elite S2, and have the parts in a box for my S1. They were taken off, and weigh a LOT! Are you using a modern compressor?

I haven't looked at any other system as I want to keep the original (albeit modified) and it fits!  You're right it weighs 18kg!  I'll be using a Sanden compressor with R134a gas - not sure yet if the expansion valve will need to be changed.

Pete

Share this post


Link to post
Share on other sites

These are the bits that I'm planning to delete - the bits with red around them:  The bit with the green tube is the vacuum valve that allows vacuum to the rest of the system when you turn the system "on".  As far as I'm concerned if I'm in the car the system needs to be always on - either heating/cooling/just blowing, so that can go.  The two open "flaps" at either side of the whole assembly will go - I'm replacing them with the same part from a heat-only system which does not have these flaps.  These flaps either close the bulkhead openings when the system is "off" or allow recirculation of the cabin air in "max cool"mode.  I'll be fitting stainless mesh over the bulkhead openings so won't need a flap to keep out rodents/bees etc!  I've never used a recirculation button on any car for 30 years so I can't see that being an issue.  If I'm deleting these flaps I don't need the vacuum motor on the left either (blue tube) or its vacuum valve - another simplification.  The two remaining marked items are the magnificently complicated water valve controls:  They modulate the vacuum to the water valve (aka dole valve) in the engine bay.  The lower one is operated by the rising ramp on the white plastic slider you can see;  the second is operated by a bimetal strip arrangement that sits on top of the heater side of the air box.  These work in tandem to increase/decrease the vacuum to the water valve, but need adjusting while measuring the airflow through them!   The water valve will be converted to cable operation - this will require a lost-motion arrangement of some sort.  This will leave just one vacuum motor and its valve - these control the position of the "mode" flap - either all the air from the fans goes through the heater matrix or it goes through the evaporator (you cannot have dehumidified heated air like you can on a modern system).  The vacuum in my setup will be provided by an electric vacuum pump so the two vacuum tanks will go as well (converting to MX5 headlight motors).  I've already started to dismantle it all so I'll post some pictures of the internals (and their mods) soon.

509735987_RIMG0371anotated.thumb.jpg.6928898f832d32024427f6f1f1b16299.jpg

 

344228247_RIMG0370anotated.thumb.jpg.b01c13f1182fcd8a30cd65de50ed060c.jpg

Share this post


Link to post
Share on other sites

The first problem you encounter on dismantling the unit are the  seized-up screws that hold the fan housings on.  They are mild steel screws fastened into mild steel "nutserts" fixed into the fibreglass housing that have been damp/wet for 40 yrs - most have to be drilled out or simply pull out of the fibreglass.  I'm going to repair the fibreglass at these points and then bond in an aluminium plate with stainless Rivnuts already in place.  This will make it easy to disassemble again in the future should I need to.

 

1601364431_RIMG0372anotated.thumb.jpg.dbaf02d99b090af56eaaeb77dfe7e9c7.jpg                                                                                           

 

The steel fan housing from this side (right hand) has two problems as far as I can see.  To make room for the "mode flap" lever the fan housing just gets bashed downwards leaving a gaping hole between the steel housing and the fibreglass enclosure.  This has a bit of tape stuck over it at the factory which stops air from the fan getting out - the tape drops off of course.  I've welded a little flange onto here to make it airtight in the future (it's an odd shape to mate with the fibreglass).

 

1174533492_RIMG0373anotated.thumb.jpg.75557f7a56ff81746589b02796b707db.jpg  

 

12767603_RIMG0379anotated.thumb.jpg.7c5d28a10ccc8ba68d82520a85461b7e.jpg

 

The other problem is future servicing;  the least reliable part of the assembly when I've finished will probably be the 40-odd year old fan motors so it would be nice to be able to replace them in the future should one stop working, but you cannot do that on this side without removing the whole aircon assembly again or taking out the pedalbox! The depressed area of the fan housing ("circled") is to give clearance of the pedal box. So... I'm going to modify the pedalbox as well to allow removal of this fan - BUT - you can only do this if you happen to have the steel-bladed fan.  If you have a plastic-bladed fan you still cannot get it out because the proximity of the fan housing to the fibreglass enclosure prevents this!  So... I'm also going to modify the fan housing in the area marked by the arrows to allow a plastic bladed fan to be used/removed in future (the plastic blades are sightly larger in diameter - they may move more air - still to be assessed).

1126580537_RIMG0378anotated.thumb.jpg.80af0721f01812ce439d168dbc7b2bfe.jpg

 

More to follow!

 

 

Corrosion is the biggest problem with the mild steel internal baffles:  I have found a better one from a second unit but this could be repaired by making a new section and welding it in.

RIMG0377.thumb.JPG.237f19a57257910b75b3a783a0ec8fdb.JPG

Share this post


Link to post
Share on other sites

Bit more done today.  Repaired the damaged holes in the fibreglass and made the aluminium insert to carry the Rivnuts - this will be bonded in using epoxy adhesive.

 

RIMG0380.thumb.JPG.988c73b9148eea0c8b40555ccbbdc535.JPG

 

RIMG0381.thumb.JPG.5f5f4c3a846bea2a1c17b97bf461fc7d.JPG

Share this post


Link to post
Share on other sites

Here's the difference between the aircon type bulkhead mountings and the heat-only type:

 

RIMG0382.thumb.JPG.9a30a6c8db8acb4d2a845cd1d706a914.JPG

Share this post


Link to post
Share on other sites

Small flange added to left hand fan housing to make it airtight (again, just tape used originally).  I've also added an extra M5 fitting (red circle) at this point - originally it was just a self-tapper into the very thin fibreglass enclosure - pulled out extremely easily.

887262104_RIMG0383anotated.thumb.jpg.db68851244e5a857ab9874587e34f2b7.jpg

Share this post


Link to post
Share on other sites

This is the internal panel that separates the heated air from the refrigerated air after it has gone through either the heater matrix or the evaporator (depending on the position of the "mode" vacuum switch).

RIMG0384.thumb.JPG.83d12457347c1d0e33f01b93e688076f.JPG

 

The problem for me is that this panel also stops heated air getting to the dash-level vents (only ambient or refrigerated air normally) and refrigerated air getting to the footwells (ambient or heated air only normally).  I've modified this panel so that it is narrower and sits parallel to the top of the evaporator.  This now allows heated air to get to the dash-level vents, screen and footwells, and refrigerated air to get to the same outlets - again depending on the mode valve position:

RIMG0385.thumb.JPG.9f5b8e0a53cc6dd96b20b4a236879fce.JPG

 

Share this post


Link to post
Share on other sites

Spent some time yesterday making a puller to remove the fragile-looking steel fan from it's shaft without damaging it or the motor or shaft.  Again, if anybody is performing the same procedure just ask!

RIMG0389.thumb.JPG.ef2fffb25db43ba83a5bb219f9f9a471.JPG

  • Like 1

Share this post


Link to post
Share on other sites

New expansion valve ready for R134a refrigerant:

 

RIMG0391.thumb.JPG.a3c3e9c949cee3077c50789075b3c63d.JPG

 

Pete

 

 

      

  • Like 1

Share this post


Link to post
Share on other sites

Fan motor mount now stadium shaped to allow much easier removal of fan from housing:

 

RIMG0392.thumb.JPG.248e5e590db925403ae8e66c9d0819a5.JPG

 

Pete

Share this post


Link to post
Share on other sites

Excellent work, I’ve been tempted to retro fit an aftermarket  heater unit but hadn’t considered the rebuild upgrade route before. Looking forward to seeing how the rest of the rebuild goes.

Share this post


Link to post
Share on other sites

Thanks Rob.  Even though it's lots of work, I like the fact that it's the original unit I'm messing with.  Both the heater matrix and the evaporator are pretty big in the unit and it should work really well.  I'm not a stickler for originality (as you can see!) but if I can modify something and make it more reliable I'm all for it.  

Pete

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...