Hi Paul,
BIG SNIP >>
You mentioned in your last post, and I quote:
"Well Leon I think you exaggerate just slightly :-) Is that one engine a
day
overhauled for the last six years or one engine every two days overhauled
for the last twelve years? :-) That's a lot of rotor cleaning. What is your
secret for cleaning rotors?"
##
No Paul, I'm not even exaggerating slightly. Now you're a smart man. I
don't think you, of all people, are mathematically inept, or are you?
I've been at it basically since 1972. That's 28 years. Even at one a
week, that's 28 * 50 = 1400. At 2 a week, that's 28 * 100 = 2800.
(Allowing 2 weeks hols per year, which also makes the maths so simple that
you can do it in your head!)
Between 1978 and 1990, when I had my own fully fledged shop, and for which
I had accurate records, very conservatively, I averaged 3 and a bit
motors a week. I closed it at the end of 1990 due to chronic hyper-allergy
to petrochemicals, which turned out to be the extreme pressure additives
in gearbox oil. Since then I have been semi-retired. I kept most of my
equipment, and continued to do motors ever since, although I have to be
extremely careful with my skin and always wear gloves.
So just during the active years in my own shop, 12 years * 3 motors a week
* 50 weeks in a year = 1,800 engines that I have not only assembled, but
for which I have been personally responsible warranty wise.
That doesn't include the engines that I built while working for other
people beforehand from 1972 to 1978, and experimenting on my own rally car
engines. I have no idea, but I know I did an awful LOT. It also doesn't
include the engines that I have either assembled for people, or supervised
them assembling since that time. I built my last engine 2 weeks before
Christmas, and I have a PP 10A twin dizzy and a current model 13B turbo
waiting for me to do over the next month when I have the spare time.
Just as a matter of interest, how many motors have you assembled??
ROTOR CLEANING
For the first 12 years or so while working for other people, I used a
variety of carbon removers, most of them had as the active ingredient, a
chemical called Methylene Chloride. Methylene chloride is a heavy,
volatile, pungent liquid that is used with a water cover on it to prevent
evaporation. It is a particularly toxic and nasty substance, but it is
particularly efficacious at removing carbon (it's the basic ingredient in
paint stripper. The trick to making the stuff last is to wash all the oil
off before placing the parts in it).
In the early '80s, after becoming sensitised to the stuff and developing
an incredibly violent allergic reaction, (which nearly killed me), I had
a hot water agitation tank specially made (75~ 80 Deg C). For the chemical
cleaner, I then used a product made by Applied Chemicals and used by Qantas
here in Australia called, of all things "Aviation". It was a buffered
inorganic chemical that worked on both aluminium and cast iron. Being
aviation related, it was dear as poison, but magic stuff, and best of
all, it was water based and didn't have toxic fumes.
The tray of the agitator was 5 ft wide, and 2 ft long, and driven by a
large compressed air cylinder. Holds QUITE a few rotors at a time }:>)
maaaaaaaaate!! Average cleaning session time was about 2 ~ 4 hours,
depending on how much was being cleaned. I would run it on demand,
usually twice and sometimes thrice a week. (It had 3 phase heating and
chewed the juice).
The chemical was so good, it was powerful enough to take the stain of the
character off most men. Most rotors would clean up in an hour or so, and
the really obdurate ones might take quite a bit longer. Up to 3 hours.
All that was then necessary was a quick blast with a high pressure water
gun, and then to scrape out the side seal and corner seal grooves. The hot
cleaning fluid softened the deposits to the point where very little force
was necessary to remove them. Absolute magic stuff. Once scraped out,
another 10 minutes in the hot tank, another quick wash, and bingo, ...
as-new rotors! A smart apprentice could clean 10 pairs of rotors in a day
if necessary!!
You also mentioned in the same post, and I again quote:
"Besides all that cleaning the rotors takes a couple of days. Actual
rebuilding the engine only a few hours".
Sure, it might take 2 days to clean a pair of rotors in your kitchen. But
if you are REALLY smart, you will take them down to you local engine
rebuilding shop and get him to hot tank them for you. Costs a few bux and
ready in a couple of hours. Just make sure they don't dog-ear the pointy
bits!! I'm lucky, I have a mate of mine who lets me use his shop! (He's
the bloke who regularly has a continual flow of busted M Type Mazda
gearboxes to fix!!).
So mate, it all depends on how good you are at it, and it also depends on
how much specialised equipment you have and how well set up you are. (See
above). It also depends on how many willing helpers and/or paid minions you
have to do all the gronk cleaning work. (Ah so glasshopper, ... you wish
to rearn to build lotaly engine? Fust must rearn to crean lota. Lule 1 Do
not dlop. Heavy son of bitch! Damage conclete!).
By that stage in my career when I had my own shop in the '80s, I had the
procedure down to a fine art. I could cut a full set of side seals and
assemble a pair of rotors in just over an hour. My foreman was even better.
He would regularly do them in under an hour. The actual engine assembly
took not much more than another hour to short-block with front cover, sump
and flywheel/counterweight. Total time about two and a half hours, and
that usually included a cup of coffee between finishing the rotors and
commencing engine assembly. Other employees then fitted all the
ancillaries and fitted it to the car, as well as doing all the stripping
and cleaning and preparation. That's where the time goes. Cleaning!
Interestingly enough, the last lot of side new seals only took me just
over 2 hours. The current side seals are really fragile, horrifically
expensive and I don't quite have the dexterity or the keenness of sight
that I used to have, so I took my time. The last engine took about an
hour to strip, just over 4 hours to wash, clean and prep, scrape gaskets,
tap out through bolt threads and an hour and a half to assemble to short
block. So most of the skillset is still there.
Also, please bear in mind that many of the engines that I was rebuilding
during the '80s were using new rotors. No cleaning required!! I'm sure you
will remember the chopped out apex seal grooves caused by ingestion of the
air-pump dust and the activated charcoal that sat in a bag in the air
filter lid?
Sincerely,
Leon Promet