Lancia Beta Forum

Technical stuff => Fuel System VX => Topic started by: markw on February 16, 2021, 01:59:37 AM

Title: Xylan coating
Post by: markw on February 16, 2021, 01:59:37 AM

With the sad passing of Guy Croft, is there anyone left who does Xylan coating of Volumex rotors? I imagine one would have to be competent enough to disassemble the unit and reassemble.

Incidentally, did anyone have this work done, and was there a noticeable improvement in efficiency?

Title: Re: Xylan coating
Post by: WestonE on February 16, 2021, 07:12:03 AM

Hi Mark

To the best of my knowledge the answer is no. I have 2 VX units (not for sale) re-built by Guy with Zylan coating. I expect the advantage to be maybe 1PSI when combined with the small tooth pulleys I have. Possibly also a win in reduced inlet temperature allowing more advance in some places without  detonation / knock. Of course I have modern ECU control including Knock sensors.

Stop chasing this modification IMHO and make sure you have forged pistons and rods plus a MLS head gasket.

Eric

Title: Re: Xylan coating
Post by: peteracs on February 16, 2021, 09:29:23 AM

Hi Eric

I do not understand why, is it because of the problem of reassembly of the blower or some other reason as there are any number offering to coat items in Xylan?

Peter

Title: Re: Xylan coating
Post by: squiglyzigly on February 16, 2021, 08:26:37 PM

I thought I read on his forum or maybe on a price list that he stopped doing the coating but don’t recall a reason.

Title: Re: Xylan coating
Post by: WestonE on February 17, 2021, 08:13:12 AM

Hi Ian

GC stopped Xylan coating some years ago because he could not get the right materials anymore. Precision and engineering knowledge is required or you end up with a jammed VX unit. It has to be just enough to close clearances without going too far.

Eric

Title: Re: Xylan coating
Post by: squiglyzigly on February 17, 2021, 09:10:17 AM

Hi Eric,
Yes I can imagine the difficulty in getting it right. Whilst I’m comfortable rebuilding my own VX units with correct clearance custom modified brass cage bearings, the rotor coating route was not a direction I was keen to try.
There’s only 4-5 thou clearance to begin with (rotor to rotor). Once you take into account the coating on each rotor and the back lash in the gears, you’re not left with much wiggle room.
I don’t know how Guy carried out the process but I expect it was a ‘lot’ more than simply coating rotors, a quick case hone and dropping them in.
Specialist skilled work.

Cheers
Ian