TIMS Posted July 26, 2014 Report Share Posted July 26, 2014 Guys Messing about in the garage this afternoon, trying to keep out of the sun, and playing with some toys, I happened on my laser thermometer!! Out of sheer interest I took temperatures on the six exhaust header pipes. Equal small distance to each and at similar small distance along the pipe from the head. The two outside were cooler, about 150 deg (no surprise in that). No's 2,4 & 5 similar at around 170 deg but no 3 consistently at around 200 deg. So my question to the cognoscenti is 1) why could that be and 2) is it a problem and how might I address it if it is? As ever, thanks in advance for your thoughts. Regards Tim Quote Link to post Share on other sites
RogerH Posted July 26, 2014 Report Share Posted July 26, 2014 Hi Tim, the surface colour and texture of the reading surface can affect the readings quite a bit. Also the cheaper instruments will give varying readings for the same conditions. Ideally a matte black surface would be nice. So, the temps out of each exhaust may be trending as you have noted but not necessarily with the temps you have got. Roger Quote Link to post Share on other sites
Andy Moltu Posted July 27, 2014 Report Share Posted July 27, 2014 If you hold it at 2000rpm or so for a few minutes do the temps even out? Quote Link to post Share on other sites
boxofbits Posted July 28, 2014 Report Share Posted July 28, 2014 Tim It might be worth looking at the colour of the plug in number 3, compared to the others. If it is whiter it will be running leaner and hotter. If yours is injection, it may be worth a check of the injector. On the other hand it could just be how the design of the manifold handles heat dissipation from each cylinder not forgetting that number 3 is towards the centre. May also be just a case of finding some other toy to play with! Quote Link to post Share on other sites
Alec Pringle Posted July 28, 2014 Report Share Posted July 28, 2014 Hi Tim, I'd be surprised if that large a discrepancy is down to operator or instrument error, and the surface texture is likely to be pretty similar between manifold pipes. Lean mixture seems far more likely to me, insufficient fuel injected or perhaps more likely an air leak ? Cheers Alec Quote Link to post Share on other sites
Steves_TR6 Posted July 28, 2014 Report Share Posted July 28, 2014 This is an interesting thread ! What revs was the engine running at for the test, if idle then perhaps unbalanced throttles or other air leak? steve Quote Link to post Share on other sites
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