Richard Armstrong
The Kuehl compressor kit as marketed by Giffiths industries in the States is trumpeted as a viable alternative to replacing the 928 compressor and hoses and from a financial viewpoint, represents a quite compelling case. $700 will buy you the new compressor, both flexible hoses, a Filter/dryer, R134a conversion ports, ample ‘O’ rings, and comprehensive instructions. My customer has the added bonus of being an airline pilot, so was able to buy the kit in America and avoid expensive shipping and import charges which would dull the price advantage.
What price advantage? Well, £370 ish at current rates compares against a rebuilt, re-sealed and bearinged compressor from Ritech Systems at £195, and the real killer – a whopping £167 and £153 for the flexible hoses if you have a later compressor, or £92 and £67 if you have the earlier – and there is VAT on top of that.
The £167 suction hose is likely to need changing as it is a common problem, but the pressure hose is quite unlikely to require changing, so there is some saving to be had there, but overall the Kuehl setup is a reasonable price.
It is also almost exactly the same weight as the later (lightest) Denso 10PA 20C standard compressor at 8kg complete with brackets and bolts etc so will be lighter if you have the pre-‘90 Denso 6E 171.
So far so good. Now we come to fitting it – and this is where it starts to come unravelled. The bracketry includes a number of separate bits, spacers, washers, spring washers and nuts instead of tapped holes
There are other irritations. It all starts with the pressure hose. The standard hose has a section of bends in solid tube which slide around the side of the radiator before attaching to the condenser, it is a fiddly job to thread through at the best of times, but the Griffiths hose is rubber all the way, and is a tight fit, awkward to bend, especially trying to get the nut onto the condenser port.
t gets worse the other end, and trying to twist the pipe to line up onto the compressor discharge port became such a pain that I dropped the compressor again, fitted the pipe and re-mounted it in position.
It seems that the alignment of the fittings is not quite right and you have to physically twist the pipe to get it on the port. This puts a permanent strain on the pipe fitting.
With the correct spacers in position, the assembly was too tight to fit into the engine bracket – just. I had to loosen the rear bracket from the compressor as well, fit it all, and re-tighten. Then do it all again to fit the discharge hose. Grrr. The nuts are necessarily on the inside, and getting a spanner on them with the belt tensioned is nigh on impossible, so you have to tighten then as much as possible before fitting the belt. Tapped holes in the bracket would be a much better answer and be tightenable after tensioning, as is the case on the standard bracket.
Belt Tension adjustment is via a piece of hex bar with a left and right hand threaded eye in each end, wind it out to tension, and lock it off with locknuts on either end. Works well – it’s just a shame that the locknuts are a strange AF size.
The clutch wire is too short. End of story. It should feed trough the air pump bracket and push into the covered spade and be cable tied onto the loom in clear view. It would be buried behind the air pump bracket if fitted as is. I lengthened the wire and fitted an in line fuse to protect the controller. Annoying
The instructions include a number of disclaimers regarding compressor warranty, and you get the impression that any problem with the compressor would result in some form of warranty cop out. Another good one is a comment that you can remove the ‘ears’ on the bottom of the compressor if you are worried about ground clearance – by hacksawing them off, but you can’t send the unit back after you have done that. Now, I’m not going to hack a customer’s compressor until it has been proved in service, which means dropping the gas out and removing the compressor after testing, or grovelling around on the floor under the car brandishing a hacksaw with it all in place. All a bit Catch 22 if you ask me.
The supplied filter dryer is a cheap aftermarket item, and is a slightly smaller diameter, and slightly longer than the original Behr unit, consequently you have to wrap it in foam to allow the clamp to hold it, and it rests on the fixed pipes at the bottom of the frame. Not really a problem, but not clever either.
Luckily the big diameter suction hose fits easily and tucks out of the way. Again, it is easier to fit with the compressor hanging. All that remains then is to finally tighten the hose nuts and test the system complete, vac it and charge.
Operation
The system was evacuated overnight charged with a slightly higher weight of R134a than is usual (950 grms), to get the right low and high side pressures, and it all seems to work just fine.The low side on the standard compressor arrangement is lower than most automotive setups, and the Keuhl sits at a more comfortable pressure.
After replacing the condenser and fixing some other climate control vacuum and water valve issues the cabin outlet temp was as low as 5.6 deg C which is on the cooler side (8-10 degrees is most common but some go down as low as 1-2 degrees depending on the lack of restrictions which is plain painful), the compressor runs smoothly and is quiet.
As an aside I personally think that the dye most people put in the system is garbage and clogs the system making it less efficient. I know most refrigeration people will disagree, but the most efficient systems I have come across go not have any dye in them. In any case dye is useless at finding the really small leaks that can plague and A/C system and irritate the hell out of customers who need their A/C ‘servicing’ every year. It does not need servicing. It needs to be leak free and left alone.
So, overall, would I recommend the kit.
No.
It’s too fiddly to fit, too many loose spacers and nuts instead of tapped holes. It’s difficult to line the pulley up by eye as recommended in the instructions – luckily it looks right as supplied. The discharge pipe fitment is tight and the fittings on either end do not align causing a slight twist which may lead to premature pipe failure, and I really don’t like the prospect of having to cut bits off a new compressor to achieve ground clearance - potentially on the car. If this is an issue on this car (and it may be) it should be done by the manufacturer before shipping it.
The clutch wire length is irritating and the whole assembly takes longer to fit than the standard arrangement.
You pays your money and takes your choice.
Richard Armstrong. Ritech Systems June 2007
