AC and over-hung pulley issues

[jbcollier]

As I mentioned before, the increased belt tension required by the AC compressor caused the over-hung pulley to flex, crack and finally shear.  I welded it back together, no problem, but the pulley would need support if it was going to do its job with no issues.  The outside of the pump underneath the pulley is little over 40 mm and the bore of the pulley is slightly more than 50 mm.  A 61808-2RS bearing clocks in at 40 x 52 x 7.  Bit on the small side so I got two to share the load.

The pump body is a casting so naturally the bearing bore is not concentric with the pump body so you can’t just machine the body to suit.  I completely stripped the pump and brought  it to my machinist.  He turned down the pump body while centred on the bearing bore, sleeved it and then machined the sleeve down to the requisite 40 mm - .001” ($250).

Here you can see the sleeve:

https://jbcollier.smugmug.com/Lotus-Europa/i-NXN2TXG/A

And here are the bearings slid in place:

https://jbcollier.smugmug.com/Lotus-Europa/i-T5QmjjP/A

In the old days, you could press out the water pump seal and re-use it.  Now seals no longer seal against the impeller.  They press onto the shaft as well as into the pump body.  So you have to get a new seal and press tool.  The press tool also centres the seal in its range of travel so it is must have to do the job correctly.

Here are the seals and the press tool:

https://jbcollier.smugmug.com/Lotus-Europa/i-LjdtHw9/A

Side view of seal, press tool again and an installed seal:

https://jbcollier.smugmug.com/Lotus-Europa/i-KRS7bhm/A

Supplier of seals and press tool with part numbers:

https://jbcollier.smugmug.com/Lotus-Europa/i-5qgswm4/A

Bearings “loctite-d" in place and machined pulley:

https://jbcollier.smugmug.com/Lotus-Europa/i-ZMxpD2K/A

It is extremely important to not load the bearings when fitting the impeller and pulley flange !!

Pressing the impeller back on with the shaft end taking the load:

https://jbcollier.smugmug.com/Lotus-Europa/i-chqkv5C/A

You have to support the shaft again when fitting the pulley flange:

https://jbcollier.smugmug.com/Lotus-Europa/i-mVzXWNd/A

Use an appropriately sized socket:

https://jbcollier.smugmug.com/Lotus-Europa/i-NcMhzSV/A

Now I have to pull the current pump, swap pulley flanges and fit the modified pump.  I’ll then strip the other pump and modify it for spares.

[surfguitar58]

...machined the sleeve down to the requisite 40 mm - .001” ($250).

And here I thought I was the only one who dimensions in millimeters and tolerances in inches! 

[BDA]

Nice bit of work there! I hope that fixes it for you, JB!

[dakazman]

Great post JB, now it looks as though you can add several more attachments to it.

I’m assuming that pump housing is only for the twin cam engine and not a wedge or hemi . They look similar to me , a novice. I would also like to rebuild my pumps with new seal and impeller,/ bearings.
Is there breakdowns on part numbers?
Maybe a different thread to discuss this?
Dakazman

[jbcollier]

This is a Renault water pump.  You might be able to by the seal and bearing from the same place but you would have to measure and see what matches.  IIRC, the TC water pump uses smaller bearings -- which is why is doesn't like tight belts.

[jbcollier]

Well my first solution didn’t work as the bearings were just too small to take the load.  They eventually overheated and noisily announced their dissatisfaction.  Time for a redesign.

I needed an larger bearing but room was sadly lacking but only by a few mm.  Thankfully the mystical machinists gods came to my rescue.

Bearing au natural:

https://jbcollier.smugmug.com/Lotus-Europa/i-2Wh3Xw3/A

Bearing machined:

https://jbcollier.smugmug.com/Lotus-Europa/i-gRDNfvn/A

Slides on just far enough now:

https://jbcollier.smugmug.com/Lotus-Europa/i-RNvKK4f/A

Next I machined up a collar which I tack welded to the pulley after carefully jigging everything up:

https://jbcollier.smugmug.com/Lotus-Europa/i-hSzwJ2W/A

https://jbcollier.smugmug.com/Lotus-Europa/i-5bgmTXz/A

I then brazed all the way around, touched it up on a lathe and applied a lashing of paint:

https://jbcollier.smugmug.com/Lotus-Europa/i-TvDqhNj/A

https://jbcollier.smugmug.com/Lotus-Europa/i-SGksRSg/A

Knock on wood — wait a minute, didn’t I do that last time — it should be fine now:

https://jbcollier.smugmug.com/Lotus-Europa/i-W5NSCcw/A

[cwtech]

"Where there's will, there's a way."

John, are you using just the new larger bearing?  ...Or, are you using the large AND the small bearing?

[dakazman]

Great work JB, 
  Its always good to knock on wood. Glad you have it re engineered, but my question is the belt still jumping at low idle speed? I'm finishing up an ac system on a car and thee experts suggest that i add a throttle soleniod that kicks in when ac is turned on ,so not to bog down the compressor.  I did not reread the entire post so please disregard if you considered it.
Dakazman

[BDA]

Very nicely done, JB! That was a really clever solution! 

[jbcollier]

Not sure what you mean by "belt jumping".  The belts have to be tight, very tight, not to slip under load.  Thus the problem with the pulley and excessive load on the WP bearings.  Once tight, they is no problem with belts slipping.  My original idler pulley was too small in diameter and the belt was cracking and breaking up.  The large alloy pulley I machined up has solved that problem.

I was going to fit an idle solenoid (more complicated than you might think with twin Dells) but I find it is not necessary in practice.  I have my idle set to 1000 rpm.  Due to the design of the system, AC load is low at idle.  It only drops to 800 rpm with the AC on.

[dakazman]

     JB , 
Oh yes, smaller diameter pulley, that’s what it was ... !

  The pictures were very clear and the whole build is very well written. Thanks for being the pioneer.
Dakazman