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Post your Plenum Photos

F1R

Well Known Member
I recently found a cracked injector line that I am very lucky did not torch me and the aircraft.

The aluminum plenum takes me a couple hours - or longer to remove. a real detriment to frequent inspections.

I am considering fabricating a new carbon fibre or fibreglass plenum that allows rapid removal / install with good sealing.

Any ideas and help is appreciated so please post a photo or two of your plenum.
If anybody knows who has "THE BRILLIANT DESIGN" please volunteer their name so we can save some time.

Thanks in advance!
 
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what about a couple of plenum inspection access covers? inspect with mirror or borescope.
 
Well, I have a large inner door that mirrors the outer cowl oil door.

While bore scopes and or mirror would be better than nothing,the inspections would be tedious and you could not pull spark plugs.

I really like tool builders piano hinge version- as seen in the Rocket section.
I also like Kevin Eldrige's various plenums on his 540 and 720 installs on his NXT,
Screen-Shot-2018-08-09-at-1.04.50-PM-e1534005242720.png


The above screen grab shows Kevins IO 720 plenum cut down to fit on a straight valve IO 540 for a recovery flight in 2013 after a thrown rod allowed him to demonstrate his excellent forced landing skills for a textbook perfect gear up soft field landing. The inlet transitions resemble my AL plenum.

Tool Builders corner joints with piano hinge and wires will likely be the fastest arrangement to remove and put back in place. Now if I can adopt the piano wires to my own top section....

I am sure there are lots of great ideas out there.
 
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Plenum

F1R,

I used to have a plenum on my IO-360 under a Sam James Cowl. Like you I always disliked doing the annual beacause it took forever to remove the bizillion screws on the plenum. And I’m not even sure it even helped cause I always seemed to have high oil temps. I got fed up one year and ditched the plenum and ordered a new baffle kit from Van’s.

So starting from scratch the baffles were installed, trimmed, removed and powdercoated. Reinstalled with the seal material that came with the kit. I made sure any air leaks were sealed took a lot of time to make sure there wasn’t any gaps. Since the baffle install there have been no more oil temp issues. CHTs are always 325-350 depending on OAT and the oil temp is usually 190-200 with a max of 210 on a really hot day during a climb.

And I don’t dread the annual anymore either- since there is no plenum the top plugs & the fuel spider are right on top with easy acess. Lots of discussion about why plenums work but in the cramped Sam James cowl it didn’t seem to be the hot setup. 80 trouble free hours since the baffling and no heat issues.
 
F1R,

I used to have a plenum on my IO-360 under a Sam James Cowl. Like you I always disliked doing the annual beacause it took forever to remove the bizillion screws on the plenum. And I?m not even sure it even helped cause I always seemed to have high oil temps. I got fed up one year and ditched the plenum and ordered a new baffle kit from Van?s.

So starting from scratch the baffles were installed, trimmed, removed and powdercoated. Reinstalled with the seal material that came with the kit. I made sure any air leaks were sealed took a lot of time to make sure there wasn?t any gaps. Since the baffle install there have been no more oil temp issues. CHTs are always 325-350 depending on OAT and the oil temp is usually 190-200 with a max of 210 on a really hot day during a climb.

And I don?t dread the annual anymore either- since there is no plenum the top plugs & the fuel spider are right on top with easy acess. Lots of discussion about why plenums work but in the cramped Sam James cowl it didn?t seem to be the hot setup. 80 trouble free hours since the baffling and no heat issues.

This is the first I have heard of using the regular baffle material with a sam james cowl. I have just ordered my cowl and baffling but didn't order a plenum because of the nightmares everyone has with the James plenums. Can you please post some pics of your install?
 
F1R,

I used to have a plenum on my IO-360 under a Sam James Cowl. Like you I always disliked doing the annual beacause it took forever to remove the bizillion screws on the plenum. And I’m not even sure it even helped cause I always seemed to have high oil temps. I got fed up one year and ditched the plenum and ordered a new baffle kit from Van’s.

So starting from scratch the baffles were installed, trimmed, removed and powdercoated. Reinstalled with the seal material that came with the kit. I made sure any air leaks were sealed took a lot of time to make sure there wasn’t any gaps. Since the baffle install there have been no more oil temp issues. CHTs are always 325-350 depending on OAT and the oil temp is usually 190-200 with a max of 210 on a really hot day during a climb.

And I don’t dread the annual anymore either- since there is no plenum the top plugs & the fuel spider are right on top with easy acess. Lots of discussion about why plenums work but in the cramped Sam James cowl it didn’t seem to be the hot setup. 80 trouble free hours since the baffling and no heat issues.

In my case the plenum works very well cooling wise. Oil temps never go over 180 to 185. The inlet transitions and sealing at the cowl inlets was nicely done. But all those screws... I have considered the conventional setup as you describe. I look at all the sloped surface on the underside pushing upward from 250 kts, and then think about adding the cooling air pressure pushing upward on the top cowl and so I have kept the plenum. I know there have been many great photos posted over the years, but I am looking to collect some of the best ideas in one place. So far Michael Robinson's piano hinge arrangement looks like the most serviceable setup.

I will be following how he does the inlet transitions closely.

Here is a screen grab of Kevin Eldrige's inlet seals and transitions on a 720
Screen-Shot-2018-08-09-at-1.01.33-PM-e1534004682847.png


But I appreciate that a good job of conventional baffle and seals to the top cowl does work well for a lot of aircraft and builders.
 
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...So far Michael Robinson's piano hinge arrangement looks like the most serviceable setup.

I will be following how he does the inlet transitions closely...

Great- now I'm on the spot!

I'd hoped to keep the plenum and some of the other radical cooling ideas secret until I'd actually flown them and could declare victory. The "transitions" seem low risk however. I have one coming out of the mold today so cant show the final integration, but in the meantime I can throw out a brief description. The cowl inlets are low Vi/Vo, so there is no real aerodynamic magic going on except a positive seal. To that end, the transitions are in essence large volume "plenum extensions" which bring the primary plenum volume forward to the cowl inlets. Since pressure recovery occurs external to the inlets, the ducts are not critical aerodynamically - they just cant restrict. Easy. Making them translate in the X,Y and Z axis and still seal is the trick. To that end, my plenum "front wall" is just that. It looks like the back wall we are all familiar with, but the extension ducts need to articulate and seal. My plan is to create a flange on the composite ducts which would easily bolt solidly to the front wall, but instead, the hole in the front wall will be oversized compared to the flange OD. The "filler" will be a membrane of silicone sheet - like a diaphragm. This membrane will be completely sealed and permanent, but will allow the rigid duct to articulate. The front of the duct will be trapped between the upper and lower cowl and sealed with rubber or an O-ring allowing some angular articulation there.

Hard to describe, but until I have pictures (and a success story), this will have to do.
 
Sam James Cowl & Standard baffles

Pictures requested by dwranda, below shots of the standard Vans baffle kit in a Sam James Cowl- no issues, normal temps all around.

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Bill Lane Plenum

BL plenum on an RV-7A IO-360 (Titan Lycoming clone).

Takes about 15 minutes to remove for inspection of the engine. Oil temps have not gone above 182 despite 95 degree Georgia heat. CHT's have been a little high on #3 and 4 (I've seen 410 on occasion during climb) - probably due to too much air supply to remote oil cooler, too small dam on #1 and lack of baffle mods to #3.

Down side is limited application of this plenum and availability.

Sorry, still don't know how to easily post pictures to VAF, hence the Dropbox link instead.

https://www.dropbox.com/sh/9n5i1bpvhwpp41w/AABgo4cqvzZUeZtc_bbHSSRxa?dl=0
 
Great pics Oly thanks! Looks like you did a very nice job with the baffles. Am I to assume that the round inlets of the cowl just feed into the squarish(is that even a word?) inlets with no real seal between the 2?
 
Great pics Oly thanks! Looks like you did a very nice job with the baffles. Am I to assume that the round inlets of the cowl just feed into the squarish(is that even a word?) inlets with no real seal between the 2?

Correct- the round Aluminum inlets are mounted on the cowl and funnels the air into the front of the engine. The baffle seals are pretty tight and careful sealing of any other small areas with black gasket sealer completed the process. It’s amazing how useful popsicle sticks can be. They make a really nice edge to smooth out the seal in a uniform manner and lightly push the sealant into any little crevices. The old plenum was so small that I wasn’t getting enough air over the #2 cylinder to the oil cooler behind #4. Was constantly fighting oil temp issues. Deciding to ditch the plenum was kind of concerning but once making the plunge it turned out OK. During the process the oil cooler opening at the rear baffle was opened up a bit compared to the old plenum. The oil cooler was also mounted pretty low so it was raised up a couple inches and now gets nice fresh air and all the oil temp issues are solved.

Not 100% sure but evidently squarish is in fact a word, from the Webster dictionary:
Definition of squarish. : “somewhat square in form or appearance.”
 
A plenum lid is merely a sealing device. The primary reason to use a plenum lid is to make sealing near perfect, which guarantees all cooling air mass flow passes between hot parts. Any cooling mass bypassing the hot parts through seal leaks does nothing but provide drag.

The secondary reason is to relieve the cowl of the significant "balloon load" created by conversion of dynamic pressure to increased static pressure in the upper plenum space. Don't underestimate the load. I would not design for less than 230 KTAS/1000 feet/85%Q. That's about 150 lbs per square foot. If your lid is three square feet, that's 450 lbs.

I have seen plenum lids which don't seal very well at their perimeter, a mechanical design issue. Recall how the rear edge of a standard cowl will pooch outwards in flight? That's internal pressure. The edges of a plenum will do the same thing and leak if the attachment is poor.

I see a lot of plenum lids with sketchy sealing at the inlets, which negates the whole concept. May as well stick with flap seals.

I see quite a few with crappy duct connections between the inlet and the plenum space. Bad duct shape reduces dynamic pressure capture. As a general rule, if the cowl inlet area is small as compared to exit area (a high Vi/Vo inlet), the ducting shape becomes more critical. If it is large (a low Vi/Vo inlet), the duct shape is not critical, so much so that really low ratio Vi/Vo requires no duct at all, just a hole. See Mooney Acclaim, Cessna TTx, or a certain well known Rocket displayed at OSH this year, all of which have no plenum lid, BTW. Their flap seals, even if well done, will not match the leak rate of a really good plenum lid and inlet seal combination, but pressure recovery is very good. My next one will be a hybrid; I'd like to try molded seals with a reinforced upper cowl half.

For now, here's a low Vi/Vo inlet, urethane rubber and glass cloth flexible ducting, and a conventional fiberglass lid. Screws directly to the cylinder head ears on #1 and #2, with clamp plates. the rubber duct experiment is now at 800 hours. The system has near zero leakage. Easy to tell; look for black dirt tracks on the inside of the white cowl.

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Plenum%20Lid%20Attach.jpg
 
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That is just amazing craftsmanship Dan. I wish I had taken the time to come look at your plane in person at Oshkosh. Everything I do on this plane is new to me so I have to learn it. I am getting close to the fiberglass portion of the build with the canopy then cowl and plenum. I have never done any fiberglass work, but keep hearing it's not that hard. I would much rather buy a plenum from someone like Bill Lane but he may not be making them anymore. I also have no builder network near me so every task is on my own. I just get over the apprehension, look at a lot of builders sites and tackle each job as it comes along. I guess the plenum is no different. I figure I'll work on it this winter in my basement unless I can find a decent one to buy.
 
My copy of DanH's plenum. I started with the standard baffle seal material and adapted the same previous metal baffling for the plenum. The plemum has a "Ultra Black RTV" gasket around the perimeter and underneath behind the spinner. Only found 2 minor leaks at the side metal baffling slip joint which was easily sealed with a little more RTV.

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I currently would like to change the sealing of the boots to the plenum lid, right now I have to cut the RTV and re-seal when removing the plenum.

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I really like the way my cowling slips into place with the inlet boots, no squeezing baffle material into place.

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If I was doing it again I might try making inlet boots to fit the standard Van's cowling and use hinge along the backside of the plenum. The side is easy to get the screw gun on, but hinge would also work well. Next time I have the plenum off I plan on looking into a hinge type attachment for the front inlet boots to the plenum lid.
 
Thanks to all for the cool(ing) photos, theory and examples. Keep the photos coming if you have any.

One of the reasons mine works is because of all the screws that do keep the top well sealed. I might try and find Torx drive or hex drive screws( to make it faster to service) and just keep on with what I have.
 
Oil cooler with James Plenum

Having high oil temp issues with plenum and RV10-sized cooler mounted on firewall using the mount from Van's on my IO360 angle valve 200HP Lycoming. I modified the 4" flange on the mount to using 4 two inch scat tubes (2 of them off plenum over #4 cylinder and 2 from cowling mounted NACA ducts to outside air.

Put exit duct on cooler and placed a handheld sports anemometer in it that's BlueToothed to my phone. While in cruise, I am seeing 75MPH air passing thru the cooler.

Cooler has -8 hoses going to and from it and I have the Anti-Splat cowl flaps.

Seems I've tried everything and my buddies in my neighborhood are scratching their heads. I would like to get to OSH next month, if possible, but I would like to see normal oil temps on my Garmin G3X!

This is a RV7, SJ plenum and cowling, dual Emag's, Superior cold air sump otherwise engine is stock and zero-timed. BTW, when I bought the engine I hauled it to Barrett Precision Engines in Tulsa and it was placed on their dyno and run WOT for one hour. Had them install a new Vernathern and it ran perfectly after a 10 year pickling experience.

Please help me.....I want to fly!
 
Having high oil temp issues with plenum and RV10-sized cooler mounted on firewall using the mount from Van's on my IO360 angle valve 200HP Lycoming. I modified the 4" flange on the mount to using 4 two inch scat tubes (2 of them off plenum over #4 cylinder and 2 from cowling mounted NACA ducts to outside air.

Four 2" dia scats = 12.56 sq in area. A single 4" scat is also 12.56 sq in area. However, the four 2" scats have a total circumference of 25.12 vs 12.56 for the single 4" tube. Bottom line is that the four 2" scats have at least twice as much drag.

Put exit duct on cooler and placed a handheld sports anemometer in it that's BlueToothed to my phone. While in cruise, I am seeing 75MPH air passing thru the cooler.

No value as a lone parameter. You're interested in cooling mass, thus you'll need velocity, area, temperature, and pressure.

This is a RV7, SJ plenum and cowling, dual Emag's...

You have the retard jumpers installed on the Emags?
 
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Thanks, Dan for quick response!

I will have to check about the Emag jumpers? Been a few years since I was doing that.

I knew that there was something scientific that was changed when we did the 4 two inch ducts. Reason that was done was, of course, there is not a lot of room to insert a 4" duct what with motor mount in the way and no easy way to get that big tube from plenum to cooler.

Since I'm not a creative guy (I do know how to fix teeth, however).....do you have an idea, fiberglassing to plenum, etc., on how to get that 4 incher installed?
 
I have a setup almost exactly like yours ( IO-360 with piston oil squirters, dual p-mags, superior cold air induction, James cowl, plenum ) and I battled oil temp issues for two+ years. I started with a large SW oil cooler on the firewall. I made numerous changes to the plenum and baffling. Nothing helped. Finally I installed a 2007x 15 row oil cooler and all my oil temp problems went away. I was able to neck the 4? baffle outlet down to 3? and still maintain oil temp. One difference between us would be you have angle valve cylinders and I opted to put parallel valve cylinders on my angle valve block. You probably generate a bit more heat.

My point being that not all oil coolers are equal.
 
DrPhil

Wow, thanks for the info. Got to get rid of 2? scats & use larger diameter scat.
Did your 17 row cooler fit Van?s mount or was that another project?
 
You have to modify the mount a little but its a very simple modification. I just did the same thing for my RV-10 build. My last post on my blog shows some pictures of the modification I made. For my RV-9 I had a home built oil cooler mount so I did have to modify it a little.
 
Numbers- you need numbers . . .

Upper and lower pressures are needed, also what are your CHT's? What are the conditions of test? Speeds - temps. Mixture - and YES check timing first.

Rest assured, you have plenty of flow area in and out of the cowl for cooling flow, it is something else, either too much heat generated (timing) or poor utilization of air - i.e. not crossing fins. Low pressure delta across the engine would be a symptom.

The SJ plenum is most restricted at the face of the heads. Looking at pressures will help diagnose the issues. Be sure the front of the plenum is not lifting and bypassing air.

Get an electronic manometer like DanH has suggested and pipe into the cabin. Tap into the static line for a reference point. Dan has used some of the rock aerators for small aquariums, so the measurement points should not present a large error.

Good baffle sealing thread http://www.vansairforce.com/community/showthread.php?t=164665&highlight=piccolo

Happy Hunting!
 
Having high oil temp issues with plenum and RV10-sized cooler mounted on firewall using the mount from Van's on my IO360 angle valve 200HP Lycoming. I modified the 4" flange on the mount to using 4 two inch scat tubes (2 of them off plenum over #4 cylinder and 2 from cowling mounted NACA ducts to outside air.

Put exit duct on cooler and placed a handheld sports anemometer in it that's BlueToothed to my phone. While in cruise, I am seeing 75MPH air passing thru the cooler.

Cooler has -8 hoses going to and from it and I have the Anti-Splat cowl flaps.

This is a RV7, SJ plenum and cowling, dual Emag's, Superior cold air sump otherwise engine is stock and zero-timed. BTW, when I bought the engine I hauled it to Barrett Precision Engines in Tulsa and it was placed on their dyno and run WOT for one hour. Had them install a new Vernathern and it ran perfectly after a 10 year pickling experience.

Please help me.....I want to fly!

Some thoughts:
- The high oil cooler exit air speed implies you are trading pressure at the cooler exit for velocity. This is exactly opposite of what you want as you increase the back pressure on the air going through the cooler - resulting in less pounds/mass of air. Try removing the exit plenum.
- The RV-10 firewall oil cooler mount is not the greatest setup for maximizing cooler air flow (several changes in cooling air direction, each increasing cooler back pressure). There are some ideas on how to modify this mount to mitigate so perhaps you can search the RV-10 posts. On my RV-10 I did not use this firewall mount.
- As been pointed out, verify your pMag setup. For this engine the most straight forward way is to set pMag timing at 5 degrees ATDC, with the jumpers in. The resulting advance curve will be (about) 20 to 30 degrees BTDC.
- I?ve seen others chase oil cooler temp problems by adding the outside NACA scoop. All proved less than successful unless you also increase exit air dimensions. After you remove the oil cooler exit plenum try a single SCAT hose to the rear engine baffle. If you can?t fit a 4?, then try 3.5?. For you engine and cooler a 3? hose should be adequate but you will need to test. The hose size is a consideration, but it is in series with the back pressure presented by the cooler itself. With your larger cooler you mitigate this.
- I assume you verified no issues with the cooler itself (like clogs). If you find you need a new cooler I recommend the Air Systems 2006X. This worked well on my RV-10 and am using it on my 180hp RV-8 (overkill but will have an oil cooler air butterfly valve).

Good luck,
Carl
 
The high oil cooler exit air speed implies you are trading pressure at the cooler exit for velocity. This is exactly opposite of what you want as you increase the back pressure on the air going through the cooler - resulting in less pounds/mass of air. Try removing the exit plenum.

Velocity alone tells nothing about cubic volume, and ultimately mass flow rate. You would also need to know the area of the duct, at a minimum.

Further, an exit duct can be used to lower pressure on the downstream side of the cooler, increasing pressure drop across the cooler, thus increasing mass flow rate. Steve Smith pointed out one method recently, a diverging diffuser duct. Or, as I've been doing for the last 850 hours, a builder can duct to an area of pressure lower than that found in the vicinity immediately behind the cooler.

Not that it matters, if Dr Phil's duct was a temporary measurement device.
 
So, here?s what I?ve done over the past two days. I have removed the four 2 in.? tubing?s to the top of my RV 10 firewall mount and replaced it with a 4 inch duct coming off the top of number four cylinder and the SJ Plenum. Went flying this morning up to 5000 feet OAT was 69? and my oil temperature was 241?. Is my next move to put an airflow oil cooleR 15 row, model number 2006A?
 
So, I have replaced the four 2 inch tubing?s with a single four-inch duct off the top of my Plenum over number four. Went flying this morning and at 5000 feet the outside air temperature was 69? and my oil temperature was 241?. Is my next move to replace the oil cooler with the airflow 2007A? I have nothing on the exit side of the oil cooler in the way of ducting. It?s open to the environment. Am I to assume that the 13 row Niagara oil cooler purchased from Van?s is a piece of junk?
 
Dr. Phil said: "Am I to assume that the 13 row Niagara oil cooler purchased from Van?s is a piece of junk?"

I'm not familiar with you, but reading the above made me question your understanding of the wisdom contained in DanH's (and other's) posts above.

Baseball bats used to drive circus tent stakes would be considered "junk" to the uninitiated. :D

Don't take it negative. I've sometimes had to read the "smarter" posts several times before I "grok" them!
 
Am I to assume that the 13 row Niagara oil cooler purchased from Van?s is a piece of junk?

Actually, I'm of that opinion. The higher fin density of the HE series Aero Classics (like the Stewart Warner) works much better. Keep in mind the number of rows is not equivalent from a Niagara to an HE series, yet they can be dimensionally the same footprint. Meaning, fewer rows on HE cooler doesn't mean smaller oil cooler.

https://www.aircraftspruce.com/catalog/eppages/heseriesoilcooler.php

All that being said, this is in no way saying your current installation isn't your problem either.. I don't waste my money on Niagara (or equivalent) coolers anymore.
 
Thanks for that info? Most helpful! So in your opinion would it be better to get an Aero Classics brand or the Airflow oil cooler (2007X) that is found on the Spruce website? I?m just trying to find which is best. I?m thinking because of the difficulty of removal of the Vans 13 row that I presently have on the firewall? I may add this additional oil cooler in series. Your thoughts?
 
Thanks for that info? Most helpful! So in your opinion would it be better to get an Aero Classics brand or the Airflow oil cooler (2007X) that is found on the Spruce website? I?m just trying to find which is best. I?m thinking because of the difficulty of removal of the Vans 13 row that I presently have on the firewall? I may add this additional oil cooler in series. Your thoughts?

You might also call Pacific Oil Cooler for an opinion. They have always been a good resource for me.
 
Thanks for that info? Most helpful! So in your opinion would it be better to get an Aero Classics brand or the Airflow oil cooler (2007X) that is found on the Spruce website? I?m just trying to find which is best. I?m thinking because of the difficulty of removal of the Vans 13 row that I presently have on the firewall? I may add this additional oil cooler in series. Your thoughts?

Don't bother with the 2007X. I don't think more area is the solution here actually, given others have success with just one. It is a differential pressure across the cooler, issue. That is coming from a guy that has 2 HE series oil coolers plumbed in series, but the environment I occasionally run my airplane in, which some may say is rather extreme, it is a required. In summary, if you just want to write a check and probably see some improvement, buy the proper HE Series Aero Classic oil cooler and swap it out.

The much harder solution is probably solve other baffle issues, like this thread talks about. Check engine timing? Oil flow through Vernatherm? etc etc The Vans inlets are huge, so you can solve this. I cool 400 cubic inches, both cylinders and oil, with less than 20 square inches of inlet area. (two 3.5" holes)
 
You?ve made my mind up and I thank you for that! I will be ordering the aero classic cooler from Aircraft Spruce immediately. I will let all of you know what happens when I finally resolve this situation of mine.
 
You?ve made my mind up and I thank you for that! I will be ordering the aero classic cooler from Aircraft Spruce immediately. I will let all of you know what happens when I finally resolve this situation of mine.

What about those P-mag jumpers?
 
Well, Dan,

It just so happens was inspecting my Emags yesterday and was wondering if 2 & 3 would be the place for the jumpers. So, I'll get the jumpers and re time.
The only time I see any cylinder in the yellow is in a sustained climb, #3 will get to 403 degrees. All the others are in the green. #4 of course is the warmest at 385 degrees.
 
It just so happens was inspecting my Emags yesterday and was wondering if 2 & 3 would be the place for the jumpers. So, I'll get the jumpers and re time.

Please report back after you get a clear idea about your new temperatures.
 
Don?t worry, I will. I appreciate all the info but you guys have given me. I spoke to EMag and I am going to make the jumper wires to go between two and three, re-time the engine at one tooth after top dead center, which he said was about 2? Then I called Pacific Coast oil coolers out in California, Wayne who is the guru there gave me the proper cooler model number to purchase, then I will set them up in parallel not in series.
 
Don’t worry, I will. I appreciate all the info but you guys have given me. I spoke to EMag and I am going to make the jumper wires to go between two and three, re-time the engine at one tooth after top dead center, which he said was about 2° Then I called Pacific Coast oil coolers out in California, Wayne who is the guru there gave me the proper cooler model number to purchase, then I will set them up in parallel not in series.

Don't do parallel, that is bad advice. I got that advice from them also. I should add, the idea there is it cuts the velocity of the oil in half as it passes through 2 oil coolers in parallel. That principle is sound, only in a perfect world where pressure to both is exactly equal. Hard to achieve in reality, I think given plumbing constraints.

In parallel, there is zero motivation for ANY oil to go to the second oil cooler. It takes the path of least resistance, and that very possibly will all be through 1 cooler. If you use multiple, they must be in series. I've built 2 airplanes with 2 coolers in series, works great. (if you really need 2)

Tom
 
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So guys, here?s how I finally fixed my high oil temperature problem? I added a second oil cooler made by Aero Classics on the passenger side of the airplane in series and placed dual 2 inch ducts off of the Plenum over number three cylinder to cool it. Now my oil temperatures in the Texas heat that I was flying in today don?t get any higher than 207?. I will still do the jumpers on my dual Emags and re-time.
 
Finally have the engine "flight ready", and since it's never going to be this clean again I figured I'd post pictures. This shows the hinge installation well. Takes about 10 seconds to get the lid off and 5 minutes to get it back on.

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The intakes are hand layups of carbon over tooling foam. I added the rings and inner ducts after the main plenum was complete. Kind of a kludge, actually. I changed directions a few times before I got here. Fortunately, with composites you can just cut out the parts you don't like and still look like a hero!

...but thank you!
 
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