RE: Low EGT's

RE: Low EGT's

At take off and intial climb out RPM is 2650 and the EGT's are #1 1128, #2 1176, #3 1110, #4 1187......

It is my understanding that on an ECi IO-360 EGT's should be between 1250 and 1300 during the high power take off portion of fliht

At cruise 75 % power EGT's will range from 1100 to 1200. At WOT high RPM
(85%) power EGT's were between 1250 and 1300.

Now with these points made I would assumn the engine on take off is runing to rich. Or the EGT probes are not showing correct temps. (Dynons EGT probes palced two inches below the exhaust attach point to the engine. Ialso find it puzzeling that at cruise the EGT's are so low considering the power settings.

I have mentioned this before but when the OAT's are cool the oil temps go up and when the OAT's are hot the oil temps go down. Temps run from 160 to 200

At WOT, 2350 to 2400 RPM, 7500 msl, 12.5 GPH, the CHT's are in the high 390's to low 400's......with #3 leading the pack at 420.....EGT's in the 1100

Throttled back to 21.3, 2350 RPM, GPH 10.9 the CHT's #1 376, #2 397,
#3 383, #4 382.....EGT's stil in the middle to high 1100's.

I have a plenum that encloses the engine compartment with Van's stock baffles. Cold air ram induction. P-Mags (I have checked the Timing and it is solid).

So any ideas as to why the low EGT's? (I probably will have to reset the fuel flow at the throttle body) (I am assuming the EGT's are accurate).

Frank @ 1L8 & KSGU ...RV7A... Phase 2

have you tested the probes in boiling water?

I would not worry about your probes. It sounds like you are running rich most of the time and I would expect them to be low while running rich. At 85% they show higher numbers and so I would say they are ok. How many hours on the engine?

RE: Not Yet

RVnoob said:

have you tested the probes in boiling water?

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Have not tested them yet!!!

Frank @ 1L8 and KSGU ...RV7A...

RE:Time

Tom Martin said:

I would not worry about your probes. It sounds like you are running rich most of the time and I would expect them to be low while running rich. At 85% they show higher numbers and so I would say they are ok. How many hours on the engine?

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Hi Tom

Just out of phase 1 prison.....41.6

According to Bob Looper (ECi / Lyco engine guru) he said I will have to make adjustments to the fuel flow system to get the EGT's at Take Off in the 1250 to 1300....

The problem I am wrestling with is to get the CHT's in the 350 to 380 area at 10.9 GPH performance cruise and 9.9 GPH at economy cruise..based on ECi recommendations.

Frank @ 1L8 and KSGU ...RV7A...

RVnoob said:

have you tested the probes in boiling water?

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fstringham7a said:

Have not tested them yet!!!

Frank @ 1L8 and KSGU ...RV7A...

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usually when you get a bad reading, it is one out of line with the other three.
when all four are consistently off... that usually is not a bad probe, (unless you have 4 bad probes)
but still, boiling the probes will get you a base line before investing time and effort everywhere.


you didn't say the TT on the engine...

EGT's

I had a very similar problem with my RV 7A, hi CHT's and low EGT's. Didn't make sense at all. I spent a lot of money and time to discover that my Rocky Mountain Instrument had been built wrong at the factory and was reading wrong. The plane was fine. I would definitely check your instrument and connections before you go to far with the troubleshooting. It sounds like your OAT and oil temps don't make sense either.

Probably more of how far they are from the engine. As you lean, what's the peak egt?

You're in the ballpark; don't sweat it too much.

As long as the mixture adjustment is set properly, don't worry about "absolute" values... They are mostly just a general guideline anyway. All you really want to know is what is "normal" for your engine, and can you find peak. My engine apparently peaks at more than 1650 according to my instrumentation, but I'm sure it does not actually get that hot. No big deal.

fstringham7a said:

At WOT, 2350 to 2400 RPM, 7500 msl, 12.5 GPH, the CHT's are in the high 390's to low 400's......with #3 leading the pack at 420.....EGT's in the 1100

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Do you have the baffle/cylinder spacer behind #3? This will drop it substantially.
Small cylinder blockers on #1 & #2 will help balance the temps.

RE:Spacer?

Hi Dan

I have heard about this spacer idea and most have said it works with a few that have had no joy. My problem is I can't visualize where to put the spacer....And even if I could get it in with my baffles so tight both on the starboard and aft side of #3 and I am not sure I could squeez one in. I sure would like to see a pix of the spacer and it's location.

I have installed theVan's supplied dams in front of #'s 1 & 2. I have been considering cutting the one in front of # 2 down a bit....just not sure how much....and not sure if that would help #3 or just cool #2 more??????

If you or anyothers have pix or ideas................HELP!!!!!!!!!!!!

Frank @ 1L8 and KSGU ...RV7A... Phase 2 underway

DanLandry said:

Do you have the baffle/cylinder spacer behind #3? This will drop it substantially.
Small cylinder blockers on #1 & #2 will help balance the temps.

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RE:Info here....

Two threads that helped me in this quest to get CHT's down...now just get to the hanger and try...........

http://www.vansairforce.com/community/showthread.php?t=8209&highlight=spacer+cylinder

and

http://www.vansairforce.com/community/showthread.php?t=16109

Did I high Jack my own thread........

Frank @ 1L8 and KSGU ...RV7A... Phase 2 the hunt for low CHT's

fstringham7a said:

Hi Dan

I have heard about this spacer idea and most have said it works with a few that have had no joy. My problem is I can't visualize where to put the spacer....And even if I could get it in with my baffles so tight both on the starboard and aft side of #3 and I am not sure I could squeez one in. I sure would like to see a pix of the spacer and it's location.

I have installed theVan's supplied dams in front of #'s 1 & 2. I have been considering cutting the one in front of # 2 down a bit....just not sure how much....and not sure if that would help #3 or just cool #2 more??????

If you or anyothers have pix or ideas................HELP!!!!!!!!!!!!

Frank @ 1L8 and KSGU ...RV7A... Phase 2 underway

Click to expand...

fstringham7a said:

Hi Dan

I have heard about this spacer idea and most have said it works with a few that have had no joy. My problem is I can't visualize where to put the spacer....And even if I could get it in with my baffles so tight both on the starboard and aft side of #3 and I am not sure I could squeez one in. I sure would like to see a pix of the spacer and it's location.

I have installed theVan's supplied dams in front of #'s 1 & 2. I have been considering cutting the one in front of # 2 down a bit....just not sure how much....and not sure if that would help #3 or just cool #2 more??????

If you or anyothers have pix or ideas................HELP!!!!!!!!!!!!

Frank @ 1L8 and KSGU ...RV7A... Phase 2 underway

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Sorry Frank,
I don't have any pictures. I just re-installed my cowling today after chasing a high erratic fuel pressure issue.

Two threads posted on this thread direct you to 2 options.

1. Cowling the inlet deflectors did nothing for me. It may be that I have the horizontal induction as you do.

2. Regarding the washers behind #3:
You will notice a screw set from the outside baffling in the corner behind #3. It's screwed directly from the baffle into the cylinder. Here you need to add 1 or 2 washers between the baffle & the cylinder. This will provide a nice gap to circulate air behind that cylinder. This will resolve the hot #3.
It's amazing how it dropped.

Too Much Information

Personally I would just fly the plane and enjoy it, nothings in a redline area. Sometimes I think we just have too much information. My advice, Take it or leave it, it's free.
Good Luck, HAVE FUN.

EGT values can vary due to the proximity of the probe to the exhaust port. If your EGT's are really too low from being way to rich, you should be able to manually lean the engine at full power, on the ground, and see significant increase in RPM from where you were full rich. In another words if the engine is way to rich and the EGTs are low because of it, it will not make full power and removing the excess fuel will cause a noticeable increase in power.
In addition your take off fuel flow should be excessive and leaning it back to normal take off fuel flows should make more power and higher EGTs. If the RPM's don't increase and the fuel flow doesn't bear out the rich mixture, I don't think you have a problem mixture wise. EGT is not the only mixture indicator.
Good Luck,
Mahlon
?The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

RE:Experimental Help

Hi Mahlon

Over the years as I have been building I have especially paid attention to engine ops/indicator issues (Mahlon quotes). This is the one area where the old EXPERIMENTAL notion of learning/education has meant alot to this challenged gear head.

Now with all that said what's it going to take to bribe you to come out west and dial this beast in.......

At any rate thanks for your great info/help/consideration/understanding of those of us that are short in knowledge and know how under the cowl.

On the next flight I will check the fuel flow at full power on take off to see if it squares up with ECi's recommendations (16.7 to 17.0 GPH).

Frank @ 1L8 and KSGU ...RV7A... Phase 2 dialing in the engine...

mahlon_r said:

EGT values can vary due to the proximity of the probe to the exhaust port. If your EGT's are really too low from being way to rich, you should be able to manually lean the engine at full power, on the ground, and see significant increase in RPM from where you were full rich. In another words if the engine is way to rich and the EGTs are low because of it, it will not make full power and removing the excess fuel will cause a noticeable increase in power.
In addition your take off fuel flow should be excessive and leaning it back to normal take off fuel flows should make more power and higher EGTs. If the RPM's don't increase and the fuel flow doesn't bear out the rich mixture, I don't think you have a problem mixture wise. EGT is not the only mixture indicator.
Good Luck,
Mahlon
?The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

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