AirTalk.org Aviation discussions newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  CHT probes          AirTalk.org Forum Index -> Aircraft Design & Building View previous topic :: View next topic   Author Message flybynightkarmarepair Guest Posted: Sat May 12, 2007 11:38 am    Post subject: CHT probes How deep is the hole a "bayonet" type CHT probe fits into? I don't like the spark plug senders, and want to drill the cast-in boss for a CHT sender to suit the probes commonly available, but without a probe in hand, I can't tell whether this is possible. Anybody who can answer this question already knows what they look like, but this forum serves an educational purpose for people other than me, hopefully, so here is what I've talking about: http://buyjpi.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=5050T&Category_Code= Back to top Kyle Boatright Guest Posted: Sat May 12, 2007 4:30 pm    Post subject: Re: CHT probes On Lycoming cylinders, I believe the CHT boss is already drilled and tapped. I know they were on mine. KB "flybynightkarmarepair" <ryoung (AT) lmi (DOT) net> wrote in message news:1178951918.733343.47970 (AT) p77g2000hsh (DOT) googlegroups.com... Quote: How deep is the hole a "bayonet" type CHT probe fits into? I don't like the spark plug senders, and want to drill the cast-in boss for a CHT sender to suit the probes commonly available, but without a probe in hand, I can't tell whether this is possible. Anybody who can answer this question already knows what they look like, but this forum serves an educational purpose for people other than me, hopefully, so here is what I've talking about: http://buyjpi.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=5050T&Category_Code= Back to top CW Crane Guest Posted: Sun May 13, 2007 6:11 am    Post subject: Re: CHT probes "Kyle Boatright" <kboatright1 (AT) comcast (DOT) net> wrote: Quote: On Lycoming cylinders, I believe the CHT boss is already drilled and tapped. I know they were on mine. KB There is a pipe like fitting that is screwed into those holes. The CHT probe is then inserted into the fitting and a BNC like cap compresses a spring that holds the tip against the head (at least it was that way with the Grand Rapids EIS that I used). The hole in the cylinder head is not very deep at all. Maybe 3/8 inch. It is really like one of those digital thermometers that you push against your head inside your ear. In another application I couldn't use the 14mm spark plug probe since I had 10mm spark plugs and instead just put it under one of the head nuts on my VW. CW Quote: "flybynightkarmarepair" <ryoung (AT) lmi (DOT) net> wrote in message news:1178951918.733343.47970 (AT) p77g2000hsh (DOT) googlegroups.com... How deep is the hole a "bayonet" type CHT probe fits into? I don't like the spark plug senders, and want to drill the cast-in boss for a CHT sender to suit the probes commonly available, but without a probe in hand, I can't tell whether this is possible. Anybody who can answer this question already knows what they look like, but this forum serves an educational purpose for people other than me, hopefully, so here is what I've talking about: http://buyjpi.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=5050T&Category_Code= Back to top Michelle P Guest Posted: Sun May 13, 2007 9:33 pm    Post subject: Re: CHT probes flybynightkarmarepair wrote: Quote: How deep is the hole a "bayonet" type CHT probe fits into? I don't like the spark plug senders, and want to drill the cast-in boss for a CHT sender to suit the probes commonly available, but without a probe in hand, I can't tell whether this is possible. Anybody who can answer this question already knows what they look like, but this forum serves an educational purpose for people other than me, hopefully, so here is what I've talking about: http://buyjpi.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=5050T&Category_Code= On Lycoming and Continental the holes are already there. You need to purchase for that manufacturer. More info on what engine you are trying to install these on would be helpful. Michelle P (A&P) Back to top flybynightkarmarepair Guest Posted: Mon May 14, 2007 6:11 am    Post subject: Re: CHT probes Thanks to CW for a useful answer. Yes, LyCon jugs have these holes, but I'm working on a VW conversion. After due deliberation, I think I'm going to go the way you went - spark plug gasket sender under one of the head stud washers, hopefully the closest to the exhaust port. The CHT sensor boss on the late model heads is actually measuring the temperature at the rocker box rim, which is hardly the hottest place on the head. Fine if you're using it for mixture control, but I'm using it as a warning, so that location, while it is less prone to mechanical damage than the usual sensor-under-the plug deal, iis not so great for accurate indication prior to head melt-down. On May 12, 6:23 pm, CW Crane <cwcr...@sbcglobal.net> wrote: Quote: "Kyle Boatright" <kboatrig...@comcast.net> wrote: On Lycoming cylinders, I believe the CHT boss is already drilled and tapped. I know they were on mine. KB There is a pipe like fitting that is screwed into those holes. The CHT probe is then inserted into the fitting and a BNC like cap compresses a spring that holds the tip against the head (at least it was that way with the Grand Rapids EIS that I used). The hole in the cylinder head is not very deep at all. Maybe 3/8 inch. It is really like one of those digital thermometers that you push against your head inside your ear. In another application I couldn't use the 14mm spark plug probe since I had 10mm spark plugs and instead just put it under one of the head nuts on my VW. CW "flybynightkarmarepair" <ryo...@lmi.net> wrote in message news:1178951918.733343.47970 (AT) p77g2000hsh (DOT) googlegroups.com... How deep is the hole a "bayonet" type CHT probe fits into? I don't like the spark plug senders, and want to drill the cast-in boss for a CHT sender to suit the probes commonly available, but without a probe in hand, I can't tell whether this is possible. Anybody who can answer this question already knows what they look like, but this forum serves an educational purpose for people other than me, hopefully, so here is what I've talking about: Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         AirTalk.org Forum Index -> Aircraft Design & Building All times are GMT Page 1 of 1   Jump to: Select a forum Aviation----------------alt.aviationAviation safety EnhancementPlanes, gliders and flying in AustraliaAviation et pilotage (Français)rec.aviationAviation (Aerobatics)Hot air, gas balloons and airshipsHang-gliding, paragliding, foot-launched flightAircraft Design & BuildingInstrument Flight RulesAviation (Classifieds)Military AircraftNaval AviationAviation (Miscellaneous Topics)Owning AirplanesAviators (General Discussions)Aviation related productsAircraft RestorationHelicopters and rotary wing aircraftsFlight SimulationSailplanesAviation (Students)Light aircraftFlying related activities in the UK Airports----------------alt.airportsEdinburgh Airport Glasgow Airport Humberside Airport Luton Airport Aberdeen Airport Glasgow Prestwick Airport  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.