Date: Wed, 20 Feb 2002 20:12:09 -0600
Reply-To: Stan Wilder <wilden1@JUNO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stan Wilder <wilden1@JUNO.COM>
Subject: Re: '80 Westfalia-- best way to drive over passes
Content-Type: text/plain; charset=us-ascii
Since we're back onto oil coolers, I'll finish up on a link I started
last week.
Subject: Installing Mazda RX7 oil cooler.
The cooler has been mounted below the Westy next to the LP fuel tank, it
hangs down to just above the height of the LP tank skid plate.
The cooler feed is from a sandwich plate between the filter and the
filter mounting.
After running the vehicle on several 80 mile round trips with 70-75
degree weather I convinced that the RX7 147 degree internal thermostat is
working correctly.
The inlet line is hot enough that you can touch it only for a second, but
at least that long.
The return line is so cool as to be deceptive (makes you wonder if the
oil is really that cool).
The RX7 cooler is about five feet from the sandwich plate and I haven't
noticed any drop in oil pressure at idle of 800 rpm or at crusing rpm of
3300.
The idiot light still goes out immediately and the gauge still bounces up
to 5 bar + on cold startups.
The oil capacity has increased by almost a full quart in filling both the
1/2" lines and the 5x2x24" seven plate cooler.
The main test of this cooler will be on a 120 mile trip in 100 degree
temperature that we get for a bout thirty consecutive days each Summer
here in Texas. (alternate test 25 mph headwinds on a 75 degree day)
Although I trust the RX7 cooler I'm somewhat puzzled by the thermostat,
bypass and overall function.
It appears that only three of the seven plates are active or possibly the
oil has cooled in this three plate process enough that I just can't feel
by touch that the additional plates are also removing heat. The three
plates are quite hot near the inlet and half way down the 24" length then
the get very cool just like the other four plates. There are four inlet
ports in the path of the thermostat plunger and possibly I just haven't
gotten enough heat developed to drop the plunger into that feed position.
I've fed kerosine through the cooler (with thermostat removed) before I
installed the cooler and it has tremendous flow through all paths of the
cooler.
I checked out the RX7 Hayes manual and about all the info it offered was
147 degree, boil the thermostat, a little plunger pops out approximately
1/8" if its working correctly. Otherwise its just a drop in plunger
(fairly sophisticated) with copper main body, brass sealing surfaces and
a spring to keep it seated until the heat relieves the spring tension and
causes the little plunger to actuate partially or fully.
I used the term *somewhat puzzled*, change that to totalled baffled.
I just keep waiting for the oil temp gauge to reach that magic 100
Celsius that I'm accustomed to seeing and it hasn't gotten there since I
installed this cooler. (I might have to go to a water temp sender and
gauge to get more accurate readings)
The CHT seems to have dropped at times under heavy load but I can't
relate it in anyway to the operation of the oil cooler. (it never got
past about 350-370 before in hard running on 120 mile periods).
I haven't paid much attention to it after installing the cooler but it
used to take about 30 minutes to get 20 degree reduction in oil temp
while running and just reducing speed/load. It will be interesting to see
if that oil temp gauge drops back any faster with the cooler in
operation.
I went to a lot of trouble to fabricate a sheet metal cover and secure a
VW fan with good air flow volume but it apperas that I probably won't
need it as long as I keep moving. (fan not installed)
For any of you with a sprit of adventure, the RX7 coolers are abundant on
*-bay and sell for various prices from 20-180$ depending on the dope
desperate for one. I paid $20.00 for mine at a local bone yard (you need
the hoses too). The sandwich plate is available from all list vendors and
the barb fittings are at your friendly Ace Hardware.
Any for those who are fearful of new things, your oil filter mount has a
bypass that will protect your engine if for some reason the cooler
thermostat locked and the sandwich plate has a similar bypass. The
ultimate danger is blowing a hose but that seldom if ever happens if you
use high temp hose rated at 200+ psi.
I would truly love to have an engine on a test stand with a troque
converter load devise to test the total of all of the functions and at
what pressure and temperatures they activate.
Jake Rabey recently full throttled a Type IV engine on a test stand and
managed to explode it just like he wanted. I think he has a video on his
web site or at least a report.
Stan Wilder
83 Air Cooled Westfalia
------------ Had to snip here, this thing has become a book
------------------------
________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today! For your FREE software, visit:
http://dl.www.juno.com/get/web/.
| 
