meowy84

Does anyone have any experience with these diesel head conversions on Cox reed valve or TD engines? Good, bad, ugly?

meowy84

Oops, I meant Davis Diesel not David Diesel.

Tim Wiltse-RCU

meowy,


My take is the Davis head is the bad and ugly. If you want a conversion head get the RJL head. The Davis head uses a funky teflon/florocarbon disk to seal the chamber. It will blow after every few runs or less. I had one and hated it. I now have a RJL head thanks to Bailey Harris and it has an o-ring on the contra piston to seal it. The important thing with a Cox conversion is making sure you have a very good cylinder/piston fit. If you have a engine that it tired it just ain't goin to happen captn'! The diesels need the seal to keep comperssion up because that is what lights the fire. Just my 2cents.

Later,
Tim

ptulmer

My Feedback: (5)

I don't know Tim, I'd give you a nickel for that advice.

I was wondering what the difference was. Anytime someone says Davis Diesel for the .049 everybody says NOOOOOO.....!

Tim Wiltse-RCU

Patrick,

It was pi$$ing me off so bad last year when I was running the engine with the DDD head. At first I thought maybe I had the engine over compressed. So I tried this and that and the thing still burnt through those disk. I was turning a 8x3 prop at 8,600 rpm so it ran well when it was running!!!! Someone had said once they made some out of the tin from a soda can and it worked pretty good. I am too lazy to cut out tin circles I guess.

Later,
Tim

flyinrog

My Feedback: (1)

I remember Tim's at a funfly,,sounded cool when it was running..he did spend a lot of time adjusting it trying to get it started though....Rog

burtcs

Don't do it!!!! As noted Davis Diesels require a teflon disk under the head. I have done the cheap trick of cutting a disk from a pop can, it works, it's a great way to waste alot of time. The RJL uses' a common rubber o-ring (this one works the best of the two types).

What you can expect is to break the journals on your cranks, bend con rods etc. The question most guys ask is do they work, yes they do, but that's not the question they should be asking. What they should ask is should I do this to my Cox engine - the answer is no. Under the best of circumstances Cox engines are probably marginal for glow (though I do wind them up) but they don't have any grunt for diesel use. Don't do it.

If you want a 1/2A diesel buy a Mills .75 (Indian made is just fine) or a PAW.

Regards - Steve B.

burtcs

Opps, PART II. 1/2A engines of any type want more either than store bought fuels contain. I have specimans of OK, McCoy and Mills. The Mills will run on 1/3,1/3, 1/3. The Cubs and McCoys (and now deseased Cox's) want 1/2,1/4,1/4.

HTH - Steve B.

PS: Somebody gave me a can of Davis Diesel 1/2A fuel. I don't have a clue whats in it, so I never used it. I make my own.

meowy84

Thanks guys.