I have been running one of the cast aluminum thermostatic oil filter sandwich adapters sold by Jegs for adding a T-stat to my oil cooler. This also served the function of eliminating about 8+ feet of oil hose and the accompanying fittings. These same adapters are sold all over the internet under names like Hayden, Trans-Dapt, etc. They all work pretty much the same - they use a small, coiled bi-metal strip (much like what is used for divorced chokes) that unwinds under heat to occlude a small bypass hole between the outlet and inlet on the adapter. The principle here is that the oil flow through the hole will eliminate most of the oil from flowing through the cooler. These use a similar theory of operation to the adapters sold by Mocal, but the Mocal units employ a spring loaded valve that slides out to occlude the bypass opening. The one I have seemed to work OK on my setup - oil got up to around 185* during normal operation, and went as high as about 235* when under high load like WOT.

Question I have - the bypass hole seems exceedingly small. I was wondering if I enlarged it slightly, if it would help the oil to heat up a little faster, and maybe let me maintain closer to 200* at part throttle cruise. I understand that oil likes to live at around 200*+ - helps to boil off moisture and allows additive packages to do their job. Obviously I don't want to open up the hole enough to keep the bimetal strip from closing it off.

Take a look at the pictures and let me know what you think. Is anyone else running one of these? If so, what are you oil temp and pressure readings with them?

Hmmm - no one wants to talk about them, huh? Boring subject, I guess. :P Surely someone is out there running this adapter. I would try to call someone in their tech support to ask directly, but I might have to brush up on my Mandarin Chinese first.

Is anyone out there using one of these? Seems like I recall at least one OSO'er besides myself using one.

I dont have one but looking at it from a machining standpoint i wouldnt just drill the hole bigger....if you have access to a bridgeport/endmill then you could go and mill the hole into an oval to open it up....or use a dremel and try it by hand....tricky part would be how that bi-metal spring covers/uncovers the hole....from the looks of it, i cant see if it actually covers the hole completly or not...there may be some open as a by-pass at all times???

Wally, I played around with it last night using a pot of water on the stove. Yes, the bimetal strip completely closes the hole when it uncoils all the way. I also think it can act like a spring and allow some bypassing to take place when it is not uncoiled all the way. When I installed the spring and heated it up it initially appeared to block the hole off at a very low temperature - around 110*, which would be far to low to send the oil completely through the cooler. I removed the spring and was able to "calibrate" it by coiling it a bit more tightly, which effectively made it uncoil more slowly. Not very scientific, but I was able to get it to where it had to get all the way up to around 190* before it completely blocked off the hole. I am thinking this might be the way to go rather than trying to make the hole larger. Ideally, I would like to see my oil temp in the range of about 200* - 225*. I think this might work. I am thinking about putting it in oil and heating that up to see if it changes the open / close characteristics.

I was running this thing before, and if I recall correctly, my oil temps were usually around 180* when idling or cruising, and elevated to around 230* after a hard WOT run. I was OK with that, but would like to get the lower number up a little higher.

FWIW, when I did an oil filter change last summer, I found that the little bimetal coil had actually fallen out of its spot and was just sitting on top of the filter. I did not notice any elevated oil temps, even though I would expect the cooler to be at least partially bypassed all the time in this situation, which is what made me wonder if the bypass hole needed to be made larger. I plan to take a punch and stake the coil in place so it cannot fall out in the future.

Hey Budman, not sure I would sweat it. 180 cruising is just fine imo. 230 is a little hot also imo. I believe in the 525EFI merc the alarm comes on a 220* oil temp.

Running the merc racing oil stats (built into filter mount), I see 180-190 cruising up to 4500rpm all day. When I stand on it and hold it to 5600-5700 for a while, temp hits 210'ish on gauge. No condensation, everything seems in check.

I actually tested a merc oil stat in a pan of water last night. It was full open at about 210, sending full oil to cooler. It began to close again at 180*.

I have them and I think I gave you the link to Jegs for them. They are set to open around 180*F. I think for the $26 price they work great. And after hard runs and an elevated temp of ~230*F, with the Mobil 1 V Twin 20w50 I run I couldn't be happier. My bearings show it in my Preparing for SuperChargers thread. Minus where something went through the oil system.

Old thread I know but I have a few questions concerning plumbing an oil thermostat.

Budman - are you running that Jegs oil thermostat directly at the block between the block and filter? I'm trying to decide whether to get the Jegs piece or Permacool's 1070. the permacool will add two more fittings than the Jegs. If I go the Jegs route it will be mounted to the remote oil filter as I don't have room to reach the back of the block.

Ramos, I mounted mine to the block in the stock oil filter location. Yes, I could see where this would be a less than ideal solution if you had twins. Starboard engine oil changes would be a b!tch. I never thought about mounting it on a remote oil filter adapter. I guess that would work. One of the reasons I ran mine this way was to do away with all the extra oil lines and fittings. I was trying to eliminate restrictions to the oil flow to/from the cooler. If you are running a lot of length on your lines you may want to step up to #12 and run one of the Mocal adapters that are designed for high flow.

I haven't figured out where I'm going to mount the remote filter yet. That will dictate which way I go.