engine and drivetrain Tii theory

[Andy74tii]

While my tii is laid up for a winter sabbatical, I have been poring over a bunch of old posts, and I think I may have come up with a theory as to why I've been running somewhat rich and my gas mileage is low.

When I lived in Houston, Mike Perkins - who rebuilt my engine - put in a 71 deg thermostat, based on trying to avoid running hot in that tropical climate. Now I live in Colorado, but still running the same thermostat. I almost never see the gauge go halfway, it's usually only about 4:00 or so, running pretty cold. So, is it possible that I might be never achieving the engine temp needed to shut off the enrichment?

While I have it laid up, I'm going to be working on freshening up a few things, and will probably replace all the hoses, flush coolant and clean out the warmup regulator. At that time, I think I will replace the thermostat with a 80 deg one, and see how that does....

Thoughts?

Thanks,

Andy

[Pierre]

I would say that you may have identified one issue. The other is altitude. Tiis do not have an air mass sensor. You will need to lean out the mixture a bit to compensate for the thinner Colorado air. A leaner mixture does run hotter too.

[tlapham]

I thought i had the same problem and i replaced the thermostat with an 80C and no difference...

It just needs tuned up all the time, very finicky and it goes out of adjustment with the old linkages.

[cthtii]

I would say that you may have identified one issue. The other is altitude. Tiis do not have an air mass sensor. You will need to lean out the mixture a bit to compensate for the thinner Colorado air. A leaner mixture does run hotter too.

I live at an altitude 6400', with the mountain passes up to around 8000'.At these elevations my '74 tii loses 20 to 30% of its torque/power compared to sea level, temp gauge reads about halfway.

My '90 K75s loses around 10%.

[landon]

Hey Andy where are you at? I have a Perkins engine in my 75 here in New Castle. Moved here about 11 years ago and I too went to a warmer thermostat as well as re-jetting of the carbs.

[landon]

Hey Andy where are you at? I have a Perkins engine in my 75 here in New Castle. Moved here about 11 years ago and I too went to a warmer thermostat as well as re-jetting of the carbs.

[Andy74tii]

I'm in the Arvada area, there's another guy Martin, who's been restoring a 73tii who lives nearby.

I was sorry to hear about Mike's passing a while back. I remember my car was in his shop at the same time Bob Murphy's was, so he'd bounce back and forth between mine and his. Incredibly expensive, but he was a super nice guy, though somewhat idiosynchratic!

It's now been almost 10 years since the restoration, along with about 66,000 miles, so it is time to take another look at some of this stuff. I'll be focusing on the injection system this time, as I do not believe the KF was ever overhauled, at least not in my ownership.

[jimk]

If your car does not overheat with a 71C stat, it will not overheat with an 80C stat. Lack of cooling is insufficient radiator (too small, dirty, etc.), not thermostat. The heat is released to the atmosphere thru the radiator, yes? Enginnering calculations show a radiator will transfer more heat when there is a hotter incoming water than colder water because the deltaT to the sink (air) temperature is greater.

Altitude has a play on cooling, in that the air density affects heat transfer. In outer space a finned cooler (incorretly called a radiator) doesn't work at all, no air!

A cool thermostat does one thing though, it puts more water in the oil. The pan has to run hot enough to drive off the combustion water from blowby.

[Andy74tii]

Good points, but I'm not really talking about overheating here. Specifically I am wondering if installing a warmer thermostat will have an effect on the operation of the warmup regulator on the back of the kugelfischer. I think after I take this all apart I will try that and see if it does anything. It's possible that the warmup injector is operating even after the car is up to operating temperature, when it should be shut off. As other posters indicated above, it often does not make a difference, and could be related to other factors, but worth a try.

[Andy74tii]

Also, one other point is that I am running a fairly recent Curt Ingraham radiator (3 row)

[Simeon]

There are many good reasons to run a hotter stat and from what you say the cooling system sounds cherry now so can take it. It may not solve all of your problems but it allows the engine to operate at the designed temperature and that can't be a bad thing.

Ran a Saab 900 for a while with no stat as a ghetto fix until I could get a new rad. I replaced the rad and then ran for a week with no stat but good cooling. It ran like a POS. Correct stat installed and it was significantly better.

[BillWilliams]

Have you looked to see if the large washer actually releases from the

enrichment lever? It is easy to see and it only needs to release enough to see light between the washer and the lever to take the warm up regulator out of the equation.