oil cooler

[Anonymous]

Here's the history:
At the end of the riding season, my gs850g (1981) blew the head gasket. I have replaced it together with few few other hoses. After that i fired it up and the first thing was oil shooting everywhere. It actually took me some 30 minutes to realise I forgat to put on rpm cable (imagine my frustration) So I got that in, and fired it up again. But carbs were so out of tune that it would stall every time I'd move.

I tried to do carbs, but in frustration ended up making my local mechanic rich. $500 for cleaning, tuning, new battery and a new chocke cable installed.
But before he took the bike he was concerned with oil pressure light being on. So he first checked the compression which was exelent in all cilinders, thanks to my rebuilding and help from people I got here.
Then he checked the oil pressure and sure enough it was good. So than he asked me did you put this oil cooler on? My answer was no, I got the bike like that. He said I didnt need it and should take it off.

My oil pressure light went on when I replaced the hoses on the cooler. I thought the oil was comming from there before I had to admit it was a blown head gasket. I thought my hoses were too long, so I kept clipping them untill they were so tight I was worried they would brake. Also I think I might have bent few fins on the cooler it self while I had it off. I'll try straightening them to see what happens. The hoses I got from local hydraulic supplys store, and they were exact match to the originals.

Is this correct? Can I take my oil cooler of? Could it be this is why my pressure light is on? And how would I patch the holes where the oil lines begin at the bottom end? Can I just put in couple short screws in there? Is there a way to check whats wrong with my pressure sensor?

Thanks for any info, and I'll see you on the roads in few weeks.

PS. sorry for the long post in terrible English, but I just wanted to present every little thing.

[SqDancerLynn1]

On the two valve 850 the oil cooler is plumbed thru an adapter that replaces the oil pressure switch adapter on the rear of the block under the carbs. So you would need to replace the adapter. If it is hooked up in another fashion????? connect the two fittings together with a short length of hose. If the oil light comes on at Idle You may have a bad
O-ring on the oil pump/stump pickup JUst remember the 850 will only have 1.5 lbs of pressure at idle

[brs127s]

I put an oil cooler on my 83 850. It uses the adapter that replaces the oil pressure switch housing. It has an elbow just under the cam chain adjuster knob with a new pressure switch. The oil goes out from the area where the switch used to be and returns at the back side of the housing. I bought the adapter and cooler from another GSR member. The adapter cam with a pressure switch. When I installed everything, my oil pressure light came on constantly. I then added an oil pressure guage on the gallery plug located just below the backside of cylinder #4 on the right side of the engine. I also made a set of inline restricters with different sized channels drilled through the middle. My oil pressure was fine according to factory manual specs, but my pressure light stayed on. I tried each restricter until I found one which kept the pressure light off. My resticter is just a piece of 3/8 round aluminum with a channel drilled through the middle to let some oil pass. I pushed it inside the hose going to the cooler and placed a clamp on the hose to hold it in place. Now, my oil light only comes on at an idle when the engine is warm.

I would leave the cooler on your bike if I were you. I know the summers in Kansas get pretty warm. That additional cooling capacity really helps.

[Anonymous]

Thanks for your replies. I'll see into it, and I will probably let it stay there.

[saaz]

A few possibilities that I think have already been covered.

Orings in the oil pump can go, reducing oil volume. Also make sure the oil pressure switch is work properly.

You may have a partial flow adaptor that sends some oil through the cooler. If too much is diverted oil pressure will be too low.

If you have a full flow oil cooler adaptor it may not be sealing properly within the oil pressure switch housing, thereby acting as a partial adaptor.

I have run a full flow yoshi oil cooler adaptor since the early 80s, no oil pressure problems. I would keep the cooler if possible as I am sure my original engine would have lasted longer with proper cooling..I was running a full sports fairing but with a smaller cooler....engine rebuild at 80,000kms

[redliner1973]

what is probably happening is that your oil pressure switch is the automotive-type, and cannot go down to the .5 to 2.0 PSI that the GS operates at. I had this problem with my GS cooler, and after alot of posting and self-indulgence, I figured out what the cause was. I personally do not feel that spacers in the lines will solve your problem, It may help the light go off, but will definately restrict what goes to the cooler. And since the cooler is a closed-loop system ( no kind of sump or anything to dump into) pressure should not be an issue. It will be at the cooler, the same as at the adapter. the original Suzuki oil pressure switch is made different than most automotive-type switches, All oil must pass through and lift off a wafer disc to make the light go out, the automotive type is not like this, hence the reason that it cannot register as low as the GS's. this is also the reason most switches will not illuminate the light when cold, but as soon as the bike gets even somewhat warm, and pressure drops, you get the low oil pressure light. Measure the pressure when the bike is warm, both at 'lights on' and 'lights off', and I bet your pressure is within the GS's limits. :twisted:

[brs127s]

Tim,

As Saaz stated, with a partial flow adapter, if too much oil is flowing to the cooler, the pressure will drop. That is why I went with an inline restrictor. With a partial flow, you are giving the oil an optional path to follow. It does not have to go to the cooler, and can follow its normal path through the engine. Therefore you allow the oil to split its normal path. If half goes one direction and the half another, then the pressure will reduce through each path, because you do not have the same volume being pushed. I used the restrictors to ensure my engine was receiving enough oil. I got the idea from block restrictors used in drag racing engines.

As far as the pressure switch, I found an automotive switch that went down to .5 lb. I can't remember the part number, but it is for a BMW car around the mid 80s to early 90s. Even with this switch, my light will come on when the bike is warm and idling. This is because it measures the pressure going to my cooler. I attribute this to fact that the original path has least resistance than the path to the cooler. The oil will flow to the path of least resistance. That is why I installed a pressure guage. I can see exactly what the pressure is when the oil passes through the engine.

[redliner1973]

I see your point, if the oil from the cooler is diverted say, to the head. But it is not, it goes right back into the adapter. when oil comes from the block, it goes into the adapter, and can go 3 possible ways, through either cooler line, or through the hole in the block that goes to the head. One of the cooler lines is directly above the outlet on the block. oil normally likes to go in a striaght line, so it goes into the rear cooler hose, out to the cooler. When it comes back through the cooler, in returns back into the adapter, but closer to the hole in the block that goes to the heads. IOW, once pressure builds in the oil system, the whole adapter gets pressurised. the stock GS oil pressure sensor is designed to open at <.5 PSI. and if it does not open, the heads do not get oil. but once off the seat, the idiot light goes out. Since you install this adapter in place of the stock sending unit, the sensitive stock switch gets replaced by a not so sensitive automotive-type switch (the switch you are talking about is available at NAPA, I cannot remember the part number, but it is available in their catalog, and can be ordered that way.). If you take the line off the end on the cooler return line, and put it in a jar, and run another hose from the return on the block, and put it in a jar also, you will find that both will flow about even. the adapter would work MUCH better if you could divide the hole where the adapter goes with something, that way the oil has to go through the cooler, then back into the other side of the adapter, and into the hole that goes to the head. but even with this, using an automotive-type switch will still cause the light to illuminate., mostly at idle. I did all this when i had my oil cooler on, and thats the reason I removed it. I knew i was getting pressure (direct pressure guage on the rt side chrome galley bolt) but ht elight was driving me nuts. Unfortunatey, I cannot 'make such a 'divided' adapter to make this work properly, as i don't have the resourses. But if i could, i would reinstall a cooler and go. :twisted:

[Anonymous]

Propflux if your sending both cooler lines into the same adapter there is no flow through your oil cooler. most coolers that I'm aware of need to be hooked up so you have pressure in and flow out. like off the oil pump thru the cooler then to the heads. oil coolers cause no drop in pressure when connected properly, they just add more oil cappacity. if you are having problems with your light being on then I would suspect the sensor is either bad or the incorrect part.

[redliner1973]

that's exactly my point, and what happens with the 'partial flow' type adapters. unless there is some kind of 'wall' to separate the inlet vs. outlet the whole thing will pressurise. If you re-read my post you will see thats what i have been trying to explain. :twisted:

[Anonymous]

yup I misread it I appologize #-o #-o

[dpep]

I am very interested in this subject but I admit I haven't quite been able follow all the points that have been made. How does the oil cooler adapter machined by forum member Terry from Oz fit into this? It was my understanding that the only option for hooking an oil cooler onto an 850 was at the oil pressure plate.

http://www.thegsresources.com/_forum/viewtopic.php?t=14080&postdays=0&postorder=asc&start=0

Here is Terry's thread.

http://www.thegsresources.com/_forum/viewtopic.php?t=14080

[saaz]

I had one of those derale coolers years ago (still have it in fact!) It relied on oil coming from behind the engine (you tapped in an elbow) then it went back in through the oil filter plate (I think) through the drain hole with another elbow adaptor. It relied on the small oil pressure differential to flow oil through the cooler (high behind the engine, lower in the filter cavity), which did bypass some of the original oil paths. I fitted an full flow adaptor rather than do it the bypass way.

The adaptor Terry does is a proper one like the Yoshi full flow type. Better as it is Australian