Home made Texaco

**Cribbs74** Sat Jan 21, 2012 7:37 am

Here is the Texaco I cobbled together for my "Solution" basically it is a proddy engine with a non SPI cylinder, Hot Texaco head and swings a 7x4 prop. Break in was completed using Sig Champion fuel 15%. It runs quicker than I thought it would and seems to move quite a bit of air. I don't have a tach so I have no idea what rpm it is turning. Throttles decently with the throttle ring, there is a slight hesitation from fully closed to fully open but, if I make the transition smoothly it throttles well enough.

It took 4 gaskets under the head to make it run right, it did a funny prop wobble type thing until I added enough gaskets. It was weird kinda swung the prop back and forth in both directions without fully turning over. I assume because the compression was too high. I have a stock Texaco head that I will try on it and I will see if that makes a difference.

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**RknRusty** Sat Jan 21, 2012 8:15 am

I've had that wobble before too. Recently I even had one run forward and when it got low on fuel, hiccup and kick itself off backwards and keep on running. I hope that never happens in the air.

microflitedude Sat Jan 21, 2012 8:22 am

RknRusty wrote:I've had that wobble before too. Recently I even had one run forward and when it got low on fuel, hiccup and kick itself off backwards and keep on running. I hope that never happens in the air.

Yep, we were getting that a lot with the Sig and KillerB. Flipping back-and-forth between TDC.

**Cribbs74** Sat Jan 21, 2012 8:31 am

RknRusty wrote:I've had that wobble before too. Recently I even had one run forward and when it got low on fuel, hiccup and kick itself off backwards and keep on running. I hope that never happens in the air.

Yeah that wouldn't be much fun. Shocked

Ivanhoe Sat Jan 21, 2012 8:36 am

I get that "wobble" quite often, I think when I overprime, sometimes carries on for a few seconds, as if the engine can't decide which way to run!

**Cribbs74** Sat Jan 21, 2012 8:36 am

microflitedude wrote:
RknRusty wrote:I've had that wobble before too. Recently I even had one run forward and when it got low on fuel, hiccup and kick itself off backwards and keep on running. I hope that never happens in the air.

Yep, we were getting that a lot with the Sig and KillerB. Flipping back-and-forth between TDC.

Hey Matt,

Are you saying it was fuel related? The sig fuel I am using is only 15%. I figured compression was too high. Even with 4 gaskets it has quite a kick when I flip the prop by hand. I had never experienced that before. I wasn't even sure what to do at first. I used my fuel bulb to stop the prop.

**Cribbs74** Sat Jan 21, 2012 8:37 am

Ivanhoe wrote:I get that "wobble" quite often, I think when I overprime, sometimes carries on for a few seconds, as if the engine can't decide which way to run!

Well then I guess this is a regular occurance. A first for me though......

**RknRusty** Sat Jan 21, 2012 11:07 am

I use the 35% SIG on my rotary valve engines, but my reedies don't run well at all with it. They run better with Glowplugboy than even SIG 25%. Maybe it's the Klotz, I don't know. But they spit and pop with SIG and they run as smooth and faster with GPB. I know it's only 17% oil, but I don't worry about that with the reedies. And 1.3 ounces of castor to a quart of GPB brings it up to 20% oil. Probably drops the nitro to 23%, but that doesn't matter.

nitroairplane Sat Jan 21, 2012 11:13 am

This problem is compression related.
It means your engine does not have enough gaskets,
It also happens to over compressed and over primed diesels.
It also happens when you over prime or flood the engine.

Surfer_kris Sat Jan 21, 2012 11:33 am

cribbs74 wrote: I figured compression was too high. Even with 4 gaskets it has quite a kick when I flip the prop by hand.

The new "insert" type heads have a higher compression than even the stock high-compression heads from cox ever had (these were desgined for the TD engine and high revs).
Four shims may get you in the neighborhood of a regular cox head , but then you may want to have an even lower compression for the Texaco application.

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