Oil Cooler Photos for My -4 Brothers

I thought some might benefit from these pics of my oil cooler install. I had tried the other more common arrangements, but it really looked like eventually I'd be dealing with a cracked baffle. I figure that cooler, when full, is a pretty heavy item and I'd really like to avoid having it shaking all over the place. I'm very pleased with the way it all came out, including the lines. The plenum was made by first carving the piece out of plain ol' styrofoam and then wrapping it with electrical tape. I waxed the outside and put on several layers of glass. Once hard, I poured acetone in and the foam dissolved. It fits absolutely perfect. The cooler mounts are made of .063 angle with nutplates and number 12 adel clamps. If anybody wants more info, like exact measurements of the oil lines, or the specific fittings used, just ask. Oh, and before I get dinged for missing cotters or nylocks in the engine bay, any hardware you see is for fitting purposes only.

A stroke of genius!

Thanks brother! Really helpful. I have spent hours juggling the oil cooler around the engine mount to see where it might fit,but have never taken it around to the right hand side. That is a stroke of genius. One question though, does it leave good access to the oil filter like that? I take it the cooler fittings are just standard right angles?

Thanks also for the details you gave on how you made the shroud out of fiberglass. I have also been wondering how to do that.

I made the decision a long time ago that I did not want the cooler on the baffles for a variety of reasons.

Its looking good,

I am just curious as to the reasons. I would think that mounting the oil cooler directly on the baffle was the obvious choice, cooling vise at least, and for simplicity. Has there been reports of the cooler falling off due to vibrations?

Oil Cooler

Hi Steve et al,

Something to be aware of is the very poor flow characteristics of scat hose. That length may affect cooling, and will get in the way of other things. I mounted my 8-row Niagara oil cooler on the LH rear baffle OK, and i have seen others do it in the -4 also. Cooling has never been a problem, nor has cracking. I had to angle the cooler rearwards with a wedge shaped piece, and I reinforced the baffle. I also mounted a diagonal strut from the cooler area to the engine case between the LH cylinders. It works.

Cool it...

I moved The Bandit's oil cooler no less than 4 times during my test period. The original location was behind the left rear cylinder, rocked back at a 45 degree angle. Oil ran hot. I then went to #8 oil lines and a new vernatherm. Better, but not the best. I then ran 3" scat through a baffle similar to the one pictured above except shorter. No luck, cruise temps still in excess of 210F. Finally I moved it out front of the left front cylinder mounted underneath the baffling with a small scoop behind the entry hole on top. I also used #8 NAPA hydraulic lines. Awesome, 185-195 in cruise on a hot day!
Every installation, engine, airplane and setup is different, your mileage may vary. The first flight will tell how it works...good luck!

Rob Ray

I agree that the hose will impede airflow, but I also know that mounting it right to the sizzling hot baffle will transfer a lot of heat to the cooler. All of the mountings I tried on the baffle suffered from very draggy (looking, anyway) transitions from baffle to cooler. I had also heard from several folks that mounted it on the firewall with very good results. Regarding oil filter access, I will have to undo the hose at the fiberglass plenum to get at the filter, but that's it. Finally, regarding getting in the way of other things, welcome to the RV-4 . It is crowded no matter what you do. Things look pretty good so far and I'm running out of stuff to do. I'l still run a blast tube to my single mag, and route wires for my engine monitor, but that's about all that's left.

The fittings are: 90 degree at the front of the cooler, 45 degree at the rear, straight at the top of engine, 45 degree at the bottom of engine. The routing goes from the front of the cooler, runs aft and loops back to the top of engine. The other line goes from the cooler to the lower engine and passes sort of below and aft of the cooler. I'll measure the line lengths later and post em.

Grant and others, thanks for the reminder about oil temps and the functionality of SCAT for moving air. Possibly this is a mistake, but once break in is finished I expect my problems all to be about keeping oil temps up. 70F here is a hot day and if it gets to 80F we all start falling over in the UK, and complain about sunstroke! Perhaps that is the reason.

My O-320 powered Supercub flies 9 mos of the year with its winterisation plate on completely covering the oil cooler. I used to think I had a problem but It is all quite normal. The vernatherm is AOK. My -9a was much the same. I am very happy if the oil temps are at 170F. Oil analysis says the oil is dry.

In all the tugging I have done, O-540 in Pawnee, and again 180 Supercub's and Robins I have never seen high oil temps. I can see it is very different for some folk.

Perhaps I will have a different experience with the -4.

What works...

Steve,
Great inputs from all involved. Realize that some are taken from trial and error in a FLYING RV4, not looking from inside the shop at a yet-to-be proven setup. As they say in Alabama, "sometimes you have to chuck a rock".

Your mileage may vary...

"All great ideas come to fruition with hours of trial and error"
Thomas Edison

Rob Ray
1500 hours RV4...

Rob,

I definitely agree and certainly am not offended by the input. However, my main reason for putting it where I did were all the comments I had read from owners of flying RV-4's with cracked baffles and inadequate cooling in the stock location. You're right, I'll just have to try it and see to determine if cooling is an issue, but the rest of the install is neat as a pin.

Steve Sampson said:

Grant and others, thanks for the reminder about oil temps and the functionality of SCAT for moving air. Possibly this is a mistake, but once break in is finished I expect my problems all to be about keeping oil temps up. 70F here is a hot day and if it gets to 80F we all start falling over in the UK, and complain about sunstroke! Perhaps that is the reason.

Click to expand...

I think I will have the same problem, keeping the temp up. But on that one day each year when my oil cooler actually will have a mission to do, I want to be sure that it works, and don't fall off in the mean time. I am also going to install an inverted oil system, so it could be that I may never have a use for the cooler, maybe I need a heater

But then again, I have a plane to build first

I have not yet got this far but I have to ask: would it not be possible to take the air from the right rear or centre baffle, to shorten the the scat hose run?

Nigel Marshall
RV-4 finishing

I did consider the center and right baffle. The right just isn't shaped right for this however. The center might turn out to be a good option if my hose is too long (never thought I'd consider too long a hose a problem ). Can anybody tell me how the flow from the center rear baffle might compare to the left rear? It'd be an easy change and I do like the idea of a shorter hose run. I also like the idea of preserving the baffle around the number 4 cylinder head. Thoughts?

Update: I just went out to the garage and was reminded why I didn't use the center baffle: It's not a big enough spot for a 3 inch hose and everybody told me to go no smaller than 3 inches. I'm keeping what I got.

Hi Guys...

Good discussion on -4 oil cooling. I have to echo the post from Steve Sampson. Here in eastern Canada my concern is getting enough oil temp. I have my ex C-172 cooler mounted on the left front, with #8 hoses and I have all of it except about an inch covered in aluminum tape. I did about an hour flight yesterday with an outside temp of 17C and my oil temp didn't get up to 160F. Sorry to mix units...temps reported in C, and my guage is in F. This has been the norm with most of the 4 owners I have spoken to about oil temps, not enough. I suspected by gauge at first and tested it in boiling water, checked out OK. Then dropped a thermometer down into the oil after a flight and it agreed as well. I would mount a much smaller cooler if I had one. Just my experience.

Joe Hine
RV4 C-FYTQ

oil cooler

my oil cooler is mounted to the firewall on the right side. I used 2 inch scat tube and took the air from the rear baffle just right of center. The oil temp never gets out of line on even the hottest days. I can reach thru the oil filler door and adjust a flapper valve the control the amount of air in. Its is usually closed if the ambient temp is 50f or lower. The only drawback is it makes working on the right mag a little tight. 350 hours and no cracks or other problems yet.

Christopher Murphy said:

The only drawback is it makes working on the right mag a little tight. 350 hours and no cracks or other problems yet.

Click to expand...

Right mag?! I don't need no steenkin' right mag! Thanks for the data point.

Center Baffle Scat tubing

Steve,
I did run my oil cooler ducting from the center baffle. The trick to getting the area with a tube that fits, is to use two tubes. This is a link to a post I previously had on the subject. http://www.vansairforce.com/community/showthread.php?p=13194#post13194
Subsequent to the pictures shown here, I have installed a plenum and round inlet cowl. With the plenum, cylinder 3 was running very cool, so I have changed the ducting to pull air off that area. I am still playing with getting the right balance between cylinder temp and oil cooling delta P. But my current oil temps are between 185 and 195 degrees on hot Texas days. The worst I get is on the taxi back to the hanger after landing where the temp occasionally gets up as high as 205.

Nice thanks

Nice work, thanks for the post. I would not worry too much about the SCAT since the Reynolds number is pretty slow. Pipers right there are loses but they are going to be pretty small. Any way nicely done. Every thing is well supported and secure. I like the aluminum reinforcements on the cooler and the Adel clamps supporting every thing off the engine mount. It's a life time installation in that you will not have any maintenance issues with it. I'm sure it will cool just fine, may be too well. Seems those RV-4's run cool, but in the winter you can just remove the scat and block the baffle and that will do it usually.

Does any one have a reason or can explain why RV-4's cool better than the other models?

gmcjetpilot said:

Does any one have a reason or can explain why RV-4's cool better than the other models?

Click to expand...

As an engineer have have to say that the cooling is proportional to the amount of air being sucked/blown through the engine compartment (considering tight fits around baffles). The main factor is probably the size, position and shape of the exit area of the cooling air. The intake is ram air in any case, and there really is not much you can do except closing it, but the outlet can be shaped and positioned to acheive large differences in cooling.

My bet is that the -4 has a smaller nose due to the cheeks, and this will create smaller positive pressure on the under side relative the other RVs with "full" cowl. But then again, a small "spoiler" just in front of the exit will make huge differences.