912 S EGT/CHT

Technical questions, advice, sharing information etc (aircraft, engines, instruments, weather and such)
Mike Cordeiro
Ready for the first flight
Posts: 48
Joined: Thu Oct 19, 2006 9:44 am
Location: Johannesburg

912 S EGT/CHT

Postby Mike Cordeiro » Tue Jan 02, 2007 6:12 pm

Does anyone know what`s the maximum diference in the temperatures
between left and right EGT`S and also CHT`S on the the 912S motor.
during cruising speed?
User avatar
Hazzard
Ready for the first flight
Posts: 44
Joined: Fri May 27, 2005 2:36 pm
Location: Emoyeni, Cato Ridge, KZN
Contact:

A slightly different question on the same subject

Postby Hazzard » Thu Jan 04, 2007 12:39 pm

I am a brand new owner of a 912s so some advice please. When setting up the instruments on the panel I wondered which info to have and which not, (money always playing a part). Given that we have no opportunity to change the mixture, the information coming back to me, while important, is impossible to address, (mixture settings etc). I am now at the point of making a decision on the Enigma. Should I take it with all the bells and whistles, (EGT, CHT etc), or does my initial point stand?
User avatar
Mogas
Pilot in Command
Pilot in Command
Posts: 882
Joined: Thu Jan 11, 2007 5:51 pm
Location: Nelspruit
Contact:

Postby Mogas » Sat Jan 13, 2007 5:53 am

Hi Mike
There is no limitation that I am aware of between EGTs or CHTs on the same engine. The main purpose of EGTs on opposite sides of the engine is to monitor the mixtures of the separate carbs. The important thing to watch for is a change in the trend when you do your panel scan.
When setting up and balanceing carbs on the 912 the goal is to have the carb slides opening as evenly as possible, only accurate way to do it is to measure the vacumes on each manifold with the balance pipe removed and the holes blanked off.
I have a very good article explaining this, unfortunately too large to post here. PM me if you need it.
Cheers
Rick
Nottaquitta
User avatar
Mogas
Pilot in Command
Pilot in Command
Posts: 882
Joined: Thu Jan 11, 2007 5:51 pm
Location: Nelspruit
Contact:

Postby Mogas » Sat Jan 13, 2007 6:01 am

Hi Hazzard
You have a class engine, don't skimp on the instruments.
All essential but what I would consider in order of importance for any 4 stroke, espetially water cooled.
1. Oil pressure
2. CHT
3. EGT
4. AMPS
Cheers
Rick
Attachments
IMG_0182.JPG
IMG_0182.JPG (47.82 KiB) Viewed 1525 times
Nottaquitta
User avatar
GR8-DAD
Top Gun
Top Gun
Posts: 700
Joined: Wed Feb 15, 2006 7:59 am
Location: Cape Town, Clanwilliam

Postby GR8-DAD » Sun Jan 14, 2007 9:54 am

I also have a 912 S in a BBaby. Have found that normal operating temp on CHT varies between 100 to 110 Deg C (goes up to 115 on climb out at full power). However, less than a 5 Deg difference between Left and Right CHT. If difference is in excess of 10 Deg I'll have a chat to the agents for sake of piece of mind. My EGT's also run just about identical.

Mike, Hazz, at what temps are you running?
Nooitgedacht: 124.8 Alt 1050 ft
S 32°16'49.8 E 18°53'33.0
Mike Cordeiro
Ready for the first flight
Posts: 48
Joined: Thu Oct 19, 2006 9:44 am
Location: Johannesburg

Postby Mike Cordeiro » Mon Jan 15, 2007 2:49 pm

Hi Mogas

My EGT`S ARE RUNNING WITH A DIFFERENCE OF APPOX. 90 Deg
BETWEEN LEFT AND RIGHT @ CRUISING .

APPROX. 840 AND 750 DEG. IS THIS NORMAL? :?
User avatar
Mogas
Pilot in Command
Pilot in Command
Posts: 882
Joined: Thu Jan 11, 2007 5:51 pm
Location: Nelspruit
Contact:

Postby Mogas » Mon Jan 15, 2007 3:58 pm

Hi Mike
My 912uls EGTs are about the same as yours, about 100 deg difference.
I fretted about this in the beginning about 70 hours ago and went to great lengths to try to get them even, going through the full carb balancing proceedure to no avail.
I don't have any excessive vibration, the EGT probes are the same distance from the heads and my carbs are well balanced.
I am now comfortable with what I have, but as mentioned before I try to often check EGTs in my scan to pickup a change in the trend.
Nottaquitta
User avatar
Ian
The sky is all mine
The sky is all mine
Posts: 486
Joined: Mon May 30, 2005 7:01 pm
Location: Crosswinds

Postby Ian » Mon Jan 15, 2007 9:38 pm

If you plan to fit 2 EGT probes, is there a big difference if you fit them to the front or the rear cylinders ?

I guess not but would like to make sure ?

Can anyone help please ? :?

Cheers ian
User avatar
Ian
The sky is all mine
The sky is all mine
Posts: 486
Joined: Mon May 30, 2005 7:01 pm
Location: Crosswinds

Postby Ian » Mon Jan 15, 2007 9:39 pm

Aah, forgot to mention... I'm talking about the 912S

Who is online

Users browsing this forum: No registered users and 14 guests