Can anyone explain why it is generally recommended that conversion diesel are to be broken in on glow fuel first.
Also, with an ABC type engine, does it matter if the engine was run on high nitro glow fuel.

Thanks,
Pete Johnson

Because it is longer time to break in ABC type dieselengine than glowengine cause dieselfuel are better in lubricating properties than glow fuel. The diesel engine running less hot than glow engine therefore the ABC sleeve are not warm enough to expanding to paralel. The sleeve will be tapered and piston are running tight in sleeve. Also we must worn out the piston to fit sleeve while break in as glow engine before converting to dieselengine.

Jens Eirik

I don't believe it is necessary to break them in on Glow, the Enya .25 Diesels Martin and I just got are ABC and didn't come with Glow Heads. The Irvine .40 Diesels are ABC and don't come with Glow heads. Dubb Jett says that the ABC style engines adjust themselves to whatever temperature they're being operated at. The perfect piston to liner seal of my Fox .74 ABC seems to have lasted longer as a Diesel than it would have as a glow engine, about 12 years now. Based on my years of fooling with and working on engines since I was 10 years old, now 62, I believe breaking them in the way you're going to use them is the way to go. I haven't messed one up yet and I currently have 120 engines.

The first couple of minutes of break-in on an ABC involves lots of stress due to the tight piston/cylinder fit. We generally use a smaller prop to let the engine rev up and heat up with minimal stress on the bushing surfaces such as the upper and lower conrod bearing, and the crankshaft bearing if it is not a BB engine. The faster these bearings run, the more they are pushed to center and cause minimal wear.
Some engines that are converted can handle these pressures, but additional pressures caused by diesel ignition can take it to (or beyond) the breaking point.
I guess part of the answer is that it depends on the engine. Purpose-built diesels are designed to take the stress.
You have a choice, follow the manufacturers instructions or try it your way. Both will probably work. Keep in mind that parts are designed for more stress in a high-performance engine than a sport engine.

George

There sure are differing amounts of the pinch, my Irvine .53 and the above mentioned Fox .74 never had any pinch, my Russian Zeus .61 had so much that it could not be flip started, it would fire and the piston would stick on the next compression stroke. My MVVS .61 will push the liner out of the block as soon as the piston gets past the exhaust port. My Fox .46 and MDS .48 have a lot of pinch also. And the amount of pinch or the lack of it doesn't seem to effect performance or longevity. Based on my "sperience".

I AM WITH hOBBSY on this my TT61 from davis never saw glow head One a new engine may be I ran 1 or 2 tanks on glow to get a
"feel" than on with the diesel head worst case senario it takes longer and they just get stronger and thats a good thing and a cmplete
waste of time with a ringed engine and as he said the irvine Q40 is the same as the irvine 40 diesel except for the head and run as
diesels fom minute one martin

I AM WITH hOBBSY on this my TT61 from davis never saw glow head One a new engine may be I ran 1 or 2 tanks on glow to get a
"feel" than on with the diesel head worst case senario it takes longer and they just get stronger and thats a good thing and a cmplete
waste of time with a ringed engine and as he said the irvine Q40 is the same as the irvine 40 diesel except for the head and run as
diesels from minute one martin ( if super tight pinch I can see it)