High Cyl Temps

[Jimmy M.]

A friend of mine installed a Westach quad cyl head temp guage this summer( 180 Lyc-170B) and is showing
pretty high temps ....often 450 to 480. Baffles are good, mixture good, timing ok.
He has the spark plug gasket type probes.
Any thoughts..????

Thanks.............Jim

[canav8]

How many hours on the Lyc?
Is it broken in already?

I have had problems with Westach instruments in the past.
Do you have an infered thermometer you can check the cyl temps with? Can you borrow one?
I have had 2 westach Cyl gauges on personal planes. I have never been fond of them.
First one was a bad guage that was new.
Second one was that the wires did not have the correct resistance and caused erronious indications. Also I have seen that the plug ring type fail on other customers planes because they were not supported well enough and vibration caused them to loose the connection at the base of the ring and fail. On the lyc 180 the bayonete type works well and is the type I prefer to use. A spring helps hold the bayonet in place and vibration is not as critical. Your milage may vary. Doug

[JHKeeton171]

I think I remember seeing a note somewhere in the Westach paper work or on their website that the spark plug gasket style probe reads approximately 50 to 75 degrees higher than the bayonet probe due to different locations on the cylinder.

[blueldr]

When it comes to instrumentation, in my non humble opinion, Westach is at the botom of the heap. You get what you pay for.

[GAHorn]

Westach instruments are inexpensive for a reason: They use UNcompensated thermocouples. This means their readouts are RELATIVE to ambient temperature...not true representations.
If you want truly accurate instruments you will have to purchase more expensive products. Alcor, EI, Shadin, etc., etc..

[Jimmy M.]

I have EI guages in a similar set up and I climb at 360 and cruise at 340.
I'll pass on the information....................
thanks guys.......Jim

[GAHorn]

Westach instruments are OK, if you simply keep tract of "trends". It doesn't much matter if your CHT reads 450 all the time. The thing that should get your attention is the day they suddently read 550....and that isn't what you are accustomed to seeing. (Keep in mind that the redline for our C145/O300 engines is 525-F/275-C.)

[Brad Brady]

Westach instruments are OK, if you simply keep tract of "trends". It doesn't much matter if your CHT reads 450 all the time. The thing that should get your attention is the day they suddently read 550....and that isn't what you are accustomed to seeing. (Keep in mind that the redline for our C145/O300 engines is 525-F/275-C.)

George,
I was going to mention that, Even with "old" instruments you have to look at trends....If your old single point CHT says 450 constantly and the engine never quits.....then that is probably "OK".....Your looking for anomalies....Brad

[Roesbery]

Been my experience that the spark plug gasket type sensors will give a different reading each time they are moved to a different position on the same plug. I always tried to put them back in the same position as before the plug was removed. But if someone else installed the plug ( annual sometimes ) almost for sure the temps would be different than before. Went to the bayonet type for that reason.

[blueldr]

Rosebery,
How and where did you install bayonet type CHT probes on Continental C-145/O-300 cylinders? I'm curious because I have, for sale, a Hexad system that has bayonet CHT probes and maybe it could be adpated for use on the C-145/O-300 engines.

[Roesbery]

I have the Lycoming, been over 30 years since I had the original engine