Hot Temps on 1969 Twinkie (non turbo)

by **Scott Ducey** » Wed Apr 29, 2009 5:17 pm

All the way down to FL last week (and back) my right engine ran hot (almost redline). In general my airplane, which has lowpresti cowls I believe (rectangular inlet) ran hot. I deal with this by managing the temps by lower climbs, using cowl flaps, etc. However on this trip the right engine ran much hotter than the left. So much so that i never closed the cowl flap for the R engine even in cruise. I never have to do that. I am having my mechanic replace the oil cooler on the R and the veritherm. HOpefully that does the trick. Does anyone else have this kind of cowl? Again, not sure if i am using the right name, but it has the rectangular inlets. If you do, do you experience warmer temperatures? I am really hoping that the replacement of the Oil Coolers / Veritherm does the trick. If it does, I am going to do the same for the L engine. I am pretty sure it is not the oil temp / pressure gauges as they appeared to go in the proper direction under the situation, i.e. when oil temp went up, the oil pressure went down.

If I am missing something here, please let me know. I appreciate any of your thoughs. BTW - my mechanic said baffles were fine, and the prop gov, which recently was rebuilt, was also fine.

Scott

by **N3322G** » Wed Apr 29, 2009 6:05 pm

Hi Scott,

LoPresti inlets are round.

What was showing hot - oil temp?, CHT? All?

Did giving it more gas help?

You might consider checking injectors for blockage.

Depending upon your probes - it may be that one cylinder was hot.

Any other symptoms? Airspeed same as previous trips? Any yaw?

by **Scott Ducey** » Wed Apr 29, 2009 6:21 pm

Yea, I kinda figured it was another cowl. I do know it is not from the factory. The cylinder heads were cool, at least that is what the factory gauge said. The only thing that helped the temp on the right engine was being in cruise and opening the cowl flap all the way. Only then would it come off of red line, but it would take a good 20 minutes to do so.

No yaw, no difference in speed. I will mention injectors to my mechanic.

Thanks Pat.

Scott

by **steen** » Wed Apr 29, 2009 6:29 pm

Ahhh, by engine temps you meant oil temp? That's a different animal and Pat's excellent suggestion to check FInjectors won't help. I think you already have the problem fixed with the oil cooler overhaul, not just a flush, and the vernitherm replacement. The engines on the non-turbos generally run too cold as the inlet/airflow design so efficient that is is really too big.
Keep us all posted.
Steen

by **Scott Ducey** » Wed Apr 29, 2009 6:36 pm

Thanks for pointing that out. I guess you can tell I am not mechanically inclined :-)

I hope you are right on your conclusion. I don't want to be sidelined for very long, the weather is getting nice. Good point on the flush, already did it at annual, and it didn't amount to much. In looking at my notes, it appears that the Cowls that I have are from Knots 2 U. So if anyone has similar experience with these cowls, I would like to hear about it. I suspect as you say that it is a oil cooler / veritherm issue.

I am keeping my fingers crossed.

Scott

by **steen** » Wed Apr 29, 2009 6:43 pm

My bet is the vernitherm if the cooler was flushed but doing both is the way to go.
Still keep us posted, will you?
Friends who have the Knots2U love them. I have about all their other mods but my original cowlings are in very good shape. I do love the Arapahoe windshield.
Steen

by **Scott Ducey** » Wed Apr 29, 2009 6:46 pm

I have a bunch of K2U mods also. I will update the forum when the work is done and let you know what i find. Thanks.

Scott

by **ics-12766** » Wed Apr 29, 2009 9:14 pm

by **Kristin Winter** » Thu Apr 30, 2009 12:34 am

by **charles Melot** » Thu Apr 30, 2009 2:24 pm

by **Scott Ducey** » Thu Apr 30, 2009 9:08 pm

by **N8632Y** » Fri May 01, 2009 1:14 pm

by **N3322G** » Fri May 01, 2009 1:56 pm

by **T210DRVR** » Mon May 04, 2009 2:32 am

I have a similar problem with my right engine, but everything is hot, EGT, CHT, and oil temp. I have engine analysers on both engines showing temps on each cylinder.

Checked mag timing and both mags were spot on. Fuel flow on the ships guage seems slightly lower on the right than left but only by .5 GPH or so. the problem is most noticeable during climb. I'm suspecting a combination of insufficient fuel flow at WOT and poor baffling. The baffling definately needs some work, but that wouldn't seem to be the cause of high EGT's at take off.

Ideas?

by **Scott Ducey** » Mon May 04, 2009 12:03 pm

I would suggest you fix the baffling and move down the chain to see if you can correct. I just replaced the vernatherm and oil cooler. I have not taken the plane out to fly yet, but will keep everyone posted on how it helped (if it helped at all).