One more thread on an oil cooler mod

[Kyler]

I have a Period 3 (P3) vintage road racing sidecar. It uses a GS 750 motor.

I blew up the '77 motor in it at Mid-Ohio. I've since then bought two more motors (a '80 and a '81). One is a spare for the next time .

Due to the very high revs and marginal air flow, IMHO an oil cooler is required. I've read most of the threads here about an oil cooler mod but want to try something different with these new motors.

I'm thinking of making an aluminum tube to replace the oil filter. I'd make the tube actually contact the filer cover so that I can redirect oil out the oil pressure switch hole and then drill a hole in the center of the cover to bring back the cool oil. I'd add an external filter and install an oil temp/pressure switch suite as well as an motor cutoff switch tied to the pressure sensor.

What do you guys think?

 

[Kyler]

Yup, 'tis I. Hack racing is big in the north east and out west. Most road racing sidecar nuts are Canadian and not far from you.

I guess I didn't explain my idea well. I'd mount the cooler in the hack where it can get airflow. The idea I expressed above seemed like an easier way to get the oil out of the motor and back in without modifying the cases.

Here's a better picture. The oil cooler is on the left in front of the gas tank where it gets air.

 

[niclpnut]

How about something like this?

you can tap and purchase fittings from any hardware store. Route the hoses how you want them, then mount the cooler or one like it.


I can't remember if the cover is modified on the reverse side to direct the oil flow or not. i recently sold this one that was mounted on a GS 11000. The filter plate is basically the same less the sending unit.


More info on oil cooler adaptation to a GS 1100 can be found here :http://www.theflyingbanana.com/oil-cooler.htm It uses the lower oil gallery bolts to feed the cooler and lists ideas to modifly flow to route the oil correctly and into the cooler.

You might be able to utilize some of the info gleaned from there to help in your mod.

 

[rapidray]

I HIGHLY recommend you NOT use the 80-82, 16 valve motors!!! Use the 3rd gen 83 or the 85 700 motors. You WILL have issues with rod & main bearings racing the 2nd gen 750s! I know this as FACT!!! Ray.

 

[niclpnut]

This is one that i almost got, but missed the bid last minute:

Said he used an 82 750 cover tapped with fittings http://www.ebay.com/itm/1982-SUZUKI-GS750E-OIL-FILTER-COVER-DRILLED-TAPPED-FOR-LOCKHART-COOLER-HOSE-/360498609420?pt=Motorcycles_Parts_Accessories&ssPageName=RSS:B:SHOP:US:101&vxp=mtr&hash=item53ef643d0c&nma=true&si=HydrOYAqgvr9pRV4SwlhIfK98Go%3D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557:
Don't know if I believe that since most of the 750 covers I've seen are flat on the reverse side.

You'll notive the configure of the inside of the cover:

The semi closed gallery with the notch is needed to direct the oil flow properly.

Nic

 

[Kyler]

I HIGHLY recommend you NOT use the 80-82, 16 valve motors!!! Use the 3rd gen 83 or the 85 700 motors. You WILL have issues with rod & main bearings racing the 2nd gen 750s! I know this as FACT!!! Ray.

Unfortunately the rules limit me to 1982 and earlier

 

[Kyler]

You'll notive the configure of the inside of the cover:

The semi closed gallery with the notch is needed to direct the oil flow properly.

Nic

Thats sorta what I had in mind but what I don't understand on those pictures is how does that redirect oil to the cooler? Looks like both fittings are on the same side of the oil flow.

 

[niclpnut]

Look at the flyingbanana site. Helps to explain it.

Nic

 

[GSScoobie]

How about building a box with tubes through it to add under the oil pan like they make for automotive transmissions?

 

[Kyler]

How about building a box with tubes through it to add under the oil pan like they make for automotive transmissions?

I have a drip pan there with oil absorbent mat (required) for when you blow the motor. Sidecar racing is really tough on the old motors and they have a bad tendency to puke. The other racers aren't fond of oil on the track. :-\\\

 

[80GS1000]

Are you using a 2 or 4 valve motor?

 

[SqDancerLynn1]

The 80-81 is a 4 valve motor and has a high pressure oiling system. If you are determined to use them ? You need to shim the oil pressure relief and add a top end oilier. They were good for eating the exhaust cams. They don't have near the dependability of the 2 valve motor 77-79 in extreme use. At the least take the top end off and clean all of the oil passages & run synthetic oil

 

[Guest]

The 80-81 is a 4 valve motor and has a high pressure oiling system. If you are determined to use them ? You need to shim the oil pressure relief and add a top end oilier. They were good for eating the exhaust cams. They don't have near the dependability of the 2 valve motor 77-79 in extreme use. At the least take the top end off and clean all of the oil passages & run synthetic oil

Or run the earlier 8 valve motor, the 16 valve is not that durable

 

[Kyler]

The 80-81 is a 4 valve motor and has a high pressure oiling system. If you are determined to use them ? You need to shim the oil pressure relief and add a top end oilier. They were good for eating the exhaust cams. They don't have near the dependability of the 2 valve motor 77-79 in extreme use. At the least take the top end off and clean all of the oil passages & run synthetic oil

Unless one of you guys want to buy them from me I'm stuck using them. Anyone near Frederick MD want a bike and spare motor?

 

[Kyler]

I think I have it figured out. The measurements work out nicely and I won't have to turn a custom filter replacement on the lathe. A simple aluminum tube can be cut to fit.

The tube the filter fits over is 19.6mm or roughly 3/4". The filter replacement tube therefore needs an ID of 3/4".

The cover has a recessed hole that has an ID of 21.6mm or roughly 7/8". Therefore the filter replacement tube therefore needs an OD of 7/8".

McMaster-Carr sells a high-pressure aluminum tube with those dimensions - voila! Length is roughly 3" and I'll play with that till I get it right. I'll seal the ends with Grey Permatex.

Now then for the plumbing.

JB Weld is pretty incredible stuff. I have a CR500 motor that grenaded and I repaired the busted case internals with JB Weld. That motor is now on its second overhaul and the JB Weld is still looking fine.

So I'll take JB Weld, fill-in the center recess to make a fitting boss for the return line; and create a fitting boss in the corner for the output line. The oil then would flow from the engine, fill the cavity where the filter used to set, be forced out the output line, through and external filter, through the external oil cooler and be returned into the center of the cover where the tube would direct it back into the motor.

Now then, the line where the oil enters the filter cavity is about 14mm. which is roughly 9/16". I think I can get by using a -8 AN line and 3/8" NPT fittings. According to my well worn machinists manual, 3/8? NPT is compatible with up to ?8 AN (1/2? hard line). It is slightly less but 1/2" NPT is just HUGE! I don't think there is enough room in the cover for that.

I'll put the oil pressure sensor inline with the external lines and put the temperature sensor in the existing pressure sensor hole.

 

[Guest]

I like this but how will it affect pressure?

Will you have to shim the pressure releif to get the same pressure in the galley as before?

What about a clogged filter. Now the new remote filter has to have a bypass built in to it.

Could you tap into the cavity and run a line for a top end oiler ?

 

[gearhead13]

There is a much easier way of doing this. There are custom oil filter covers that I have seen on ebay and other places. In fact I have one on my bike. When the cover is bolted on, the oil is directed out to a -8 AN fittings and braided line that runs to my oil cooler. It is then directed back to the filter cover, through the filter and to the engine.
I dont really need the cover as I have an 1100 and have the ports to plumb the cooler to the passages on the 1100 that were never used until later models. I an either going to plug the passages on it or find an 1150 cover.
You need to make sure that your lines and fittings are large enough to not cause a pressure drop. Not only do these engine eat exhaust cams but have been known for weak bottom end oiling. A top end oiler would be a must IMO.

 

[Kyler]

I like this but how will it affect pressure?

Will you have to shim the pressure releif to get the same pressure in the galley as before?

What about a clogged filter. Now the new remote filter has to have a bypass built in to it.

Could you tap into the cavity and run a line for a top end oiler ?

It is a closed loop so pressure should not be affected but I am adding a recording electronic oil pressure/temperature gauge so I can find out.

I've been told to shim the relief valve and plan on doing that if I can find a reference saying what to do!
I change oil filters every race so I'm not too worried about the filter clogging. The new filter will be 2x the size of stock.

I've emailed with the maker of the Vortex top end oiler. His oil feed won't work on this motor. I'm thinking of using his head manifolds and adding an oil distribution manifold after the oil cooler to divert some of the oil to the top end.

 

[Kyler]

There is a much easier way of doing this. There are custom oil filter covers that I have seen on ebay and other places. In fact I have one on my bike. When the cover is bolted on, the oil is directed out to a -8 AN fittings and braided line that runs to my oil cooler. It is then directed back to the filter cover, through the filter and to the engine.
I dont really need the cover as I have an 1100 and have the ports to plumb the cooler to the passages on the 1100 that were never used until later models. I an either going to plug the passages on it or find an 1150 cover.
You need to make sure that your lines and fittings are large enough to not cause a pressure drop. Not only do these engine eat exhaust cams but have been known for weak bottom end oiling. A top end oiler would be a must IMO.

My method forces all the oil out into the external system and maintains pressure. The stock cover has a bypass. The bypass lowers pressure to the cooler. Also, this way I get my external filter which I really want. The top end oiler is on my list. Even my '77 motor had cam galling which I blame on the way the PO plumbed the external cooler. I'm doing this one-step at a time, checking pressures, etc before adding something else.

I need to do it right. The thought of a motor shredding mid-race isn't pretty particularly since is is only inches away from the family jewels and my face.

 

[gearhead13]

One of the problems with the exhaust cam on these engines is the split exhaust rocker, If you have the valve cover off you will see what I mean. When I ran my 750, I used two sets of intake rockers (without the split) and a stock 1100 cam (same size cam) 1100 and 750 rockers have different spacing.