Date: Sun, 9 Sep 2012 21:38:12 -0700
Reply-To: Poppie Jagersand <poppie.jagersand@YAHOO.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Poppie Jagersand <poppie.jagersand@YAHOO.CA>
Subject: Re: [Diesel-Vanagon] How does coolant circuit to oil cooler work?
In-Reply-To: <1347131996.35140.YahooMailNeo@web163406.mail.gq1.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1
I tried the experiment proposed in the post below. (varying the proportion of coolant between the parallel loops through radiator and oil cooler respectively)
All tests were highway driving at 100km/h, 400C EGT, little wind. 10km drive in each of the three conditions.
Three temps where monitored: Regular coolant temp with the regular vanagon gauge, oil cooler inlet temp with a VDO gauge, and oil cooler outlet temp with a digital thermometer (the only accurate readable of the three...).
1. Regular flows. Coolant temp at 3/4 of Vanagon gauge. Oil cooler outlet temp 97C, VDO oil inlet temp just above 220F (*)
2. With about 1/2 area restriction on the oil cooler inlet: No substantial change in any of the temps.
3. With the oil cooler hose almost completely clamped off: Coolant temp down a little bit to 5/8 of gage. Oil outlet temp down 3-5C to 90. VDO gauge shows just below 220F
I can unfortunately only check temp changes, as none of the temp meters are calibrated to report correct absolute temp.
The most reliable conclusion seems to be that reducing the coolant flow to the the oil cooler circuit has little harmful effect.
The corresponding increase in flow to radiator may be a beneficial, but more detailed measurements would be needed to confirm. I might put a 4th tem sender in coolant return temp from rad.
(*) Before I put in the new VDO vision gauge I tested it in a pot of boiling water. A calibrated digital thermometer shows 97C (which is correct water boiling point for the 2000ft altitude here), while the VDO showed near the 180F mark (not near the 220 as it should have. (It has no markings between 180 and 220). Therefore I suspect the VDO reads low, but the scale is non-linear and it is difficult to tell how much to add. A rough guess would be that the 220 reading would be more like 250-260F oil temp. FLAPS aftermarket oil temp gauges I've tried have been similarly inaccurate. Irritating that one cannot obtain an accurate automotive temp gauge.
Martin (and '82 Westy 1.9TD Poppie)
________________________________
From: Poppie Jagersand <poppie.jagersand@yahoo.ca>
To: "Diesel-Vanagon@yahoogroups.com" <Diesel-Vanagon@yahoogroups.com>
Sent: Saturday, September 8, 2012 1:19:56 PM
Subject: Re: [Diesel-Vanagon] How does coolant circuit to oil cooler work?
A third, easy option I'm tempted to try is to slightly vary the flow to the oil cooler in the current design. Since slightly less flow to the oil cooler loop means more flow to rad loop, that could potentially improve overall cooling capacity.
To find what effect varying restrictions have I was planning to pin the inlet hose to the oil cooler varying amounts by pressing on it with an adjustable clamp.
I'll monitor oil temps both on the inlet (normal temp sender location) and cool oil outlet to turbo, where I have placed a second sensor, to make sure cooling efficiency of the oil cooler is not compromised.
If it works out, it would be easy to install a suitable size permanent flow restriction using a bushing or washer just in front of the oil cooler inlet.
Martin (and Westy 1.9TD Poppie)
[Non-text portions of this message have been removed]
| 
