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gregschultz Date registered: Jun 2006 Location: Roswell, GA Vehicle(s): '86 300GD; 08 ML 320 cdi; 05 E320cdi | best location for pyrometer temp sensor on diesel Well, the m110 to om617 conversion is underway on my G. Sean and Jerry and Steve are having at it each and every saturday until completed. I spoke to Steve earlier today and there is some debate amonst the three of them on this topic: is it best to place the temp sensor for a pyrometer: a, in the exhaust manifold (tap and die); or, b, in the exhause downpipe (drill and weld bung)? It is my belief that if I ceramic coat the exhaust manifold and the down pipe, then the temp difference between the manifold and the downpipe will be minimal and unimportant, as a practical matter. And, I'd rather they drill and weld the down pipe than the manifold because an "oops" is less expensive to rectify. Thoughts? | ||
#66917 | |||
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Merz-Ben Extreme Veteran Date registered: Aug 2006 Location: Floyds Knobs, IN 47119 Vehicle(s): 230G, U1200, U1250 DoKa, U1300L, U1500, U1700, 416 Posts: 377 | RE: best location for pyrometer temp sensor on diesel Greg, I would recommend that you put the EGT sensor in the manifold. The exhaust temp drop between the manifold to the downpipe is significant enough that if you plan to hotrod the engine you risk meltdown with the temp reading that you get out of the downpipe. I know two cummins powered trucks that I work on for other people that had the temp gauge in the downpipe and they had catastrophic meltdown while running at close to acceptable EGT. These were running at extreme HP, but if you have a malfunction it might keep you from breaking expensive turbo or engine parts. Just my two cents. Cheers, Ben | ||
#66921 - in reply to #66917 | |||
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hipine Date registered: Jul 2006 Location: US, CO, Bailey Vehicle(s): 460 1980 280GE w. 617A | RE: best location for pyrometer temp sensor on diesel My input is that if you're worried about the ability to make a pipe tap correctly, you should have picked a different project. But then, if you have Steve working on it for you, allowances have to be made.... :^) Seriously, though....You get the best readings in the manifold, so put it in the manifold. Why bother trying to "rationalize" why you think the readings you're getting are "close enough" to reality, when it's so easy to just get accurate readings? At least that's the line of thinking I went through with myself before I put mine in the manifold. I used the boss where the front-most mounting bolt for the rear (starter) heat shield went into the manifold. I put a 1/4" drill through at that location (clearance for the pyro probe I had) then followed that up with the drill and tap to proper depth for the npt compression fitting that holds the pyro probe in my case. Lastly I drilled the forward mounting hole in the heat shield bigger so that it could be captured by putting the npt fitting through it, rather than the bolt as was original. This locates my pyro probe between the #3 and 4 exhaust branches to be sure and capture exhaust temp coming from the rear two cylinders where my mechanic friends tell me most diesel problems surface (in the form of head gasket leaks from overheats). Another tip from Warren to help with heat issues was to move the water outlet fitting from the left side of the head to the rear of the head. I did that on mine before I put the motor in. Used teh same hose that used to go on the left side, just put it on the rear and then used a metal elbow to go toward the heater inlet. -Dave G. PS - I had my exhaust and intake manifolds ceramic coated too. Didn't bother with the turbo or the downpipe. My underhood temps seem very cool, at least not noticeable at all when the hood is opened after a long run. | ||
#66935 - in reply to #66917 | |||
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