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is an oxy case stronger than a T4 case? I am looking to do a real oddball project and need the toughest bottem end possible. I also need to be able to do several iterations, so being able to use readily available bits like 2.1 or 1.9 cases help a lot.


what was the strongest lower end VW ever sold?

An oxy with all T4 mains would be pretty solid.

VW managed to regress some on the T4s oiling improvements, but that's fixable with a looong drill bit...

how much stronger than a T4 case are we talking here? a marked improvement, or just a tad? and as I am still doing research on the whole oxy thing, this would use what style cranks? T1 and 2.1/1.9s? I am planning a long stroke small bore motor.

everything is up in the air, just trying to gather little details

I didn't say it would be stronger... It would probably be close, same materials etc.

The T4 has better cooling potential, but is comparatively stroke limited. The T4 head stud pattern is not optimal, but with (non-stock casting based design) aftermarket heads that's likely not much of an issue.

The WBX is slightly bore limited, and ~30% cooling limited (in air cooled form) vs a T4, and liely still would hold a slight margin even w/T1 style ex port heads simply due to having much more fin area.

Same case materials/mfg method... The T4 case is beefier in some key areas. An all T4 main WBX crank would be relatively shorter/stiffer.

To push the limits of ~ anything just mentioned, it would be a near max effort/~unlimited $$$ build.

A large T4 w JPM heads would likey be a match or exceed the reliabilty of an equivalent oxy, and would likely cost about the same, perhaps with a nod to the WBX on price/HP, and the T4 for reliability due to cooling margin.

If Paul H can get his new heads done as I think he has planned, and near price target, I think it is possible the T4 could cost less/HP in the end, but it will likely be fall or next spring before they materialize in any form.

ok so i will confess to what this is for. I am collecting info on my aircooled diesel engine, and trying to test the waters to see what stock parts I can use and what I need to have made, what needs mods etc. since diesels actually run cooler, cooling isn't too big an issue. as you seem to know a lot about the matter, what would your opinion be, as to what would be the best platform? goal is 55-90 hp range, 18-22 CR, likely to get a turbo.

anyways, who has the best stud pattern? sounds like oxy? best crank and mains? opinions and facts are waht it is all about.

Ah, that...
Deutz 912 diesel heads may be adaptable to a T4... the cylinders are.

Piledriver wrote:Ah, that...
Deutz 912 diesel heads may be adaptable to a T4... the cylinders are.

Not easily.
IIRC, the intake and exhaust ports are on the same side,
opposite the push rods.Not a problem on an inline motor,
it would make cooling difficult on a Boxer motor.

Might be possible to create T1 style exhaust, with enough welding.

There were some diesel threads in the Type4rum.

I don't like the t4 case as much, it strikes me as more car application over the wasser's van/truck application.

The two advantages I see with the t4;
A money no object crankshaft could be made more ridged (longer and larger mains)
Through bolts on the mains

Everything else I would guess would be less of a nightmare, either would be lots of custom one off parts.

The wider bore spacing on the T4 might be helpful.

That would let you use the Deutz barrels.

true. I think the biggest stumbling block on the diesel project is finding the strongest case/crank combo possible, so any insight here is great. I figure I will look thru jakes store at his cranks, as I may need to stroke the beast to make a diesel happy, however a bore of around 92-94 has been set in stone already. Just to keep things sane and simpleish.

"...Sane and simplish" would be to swap a 1.9 TDi in

Piledriver wrote:"...Sane and simplish" would be to swap a 1.9 TDi in

fusername, pile i think sums it up. i cant see it working at all with any aircooled v.w motor, the thermal efficiency can never be there, the mechanical integrity for retaining the heads isnt there, at least within sane investment in re engineering it all, it would need some sort of girdle system thro' bolted side to side to keep it from pulling apart, let alone cooling it. and thats before the turbo goes on! a wbx offers a better base to start with, better bolt anchors nice and deep set, the water jacket adds great strength to the case giving good rigidity and the thermal control is done for you. plus T4 bearings , and the water kills the terrible diesel racket, imagine that aircooled.? its
unlike me to be negative, and your to be applauded for thinking out the box, which is how we got here after all, and i have a feeling this will run a bit. but good luck with the project whatever happens

Subrau boxer diesel..... 2L 150 bhp.....

fusername wrote:true. I think the biggest stumbling block on the diesel project is finding the strongest case/crank combo possible, so any insight here is great. I figure I will look thru jakes store at his cranks, as I may need to stroke the beast to make a diesel happy, however a bore of around 92-94 has been set in stone already. Just to keep things sane and simpleish.

As we told you in the other thread, if you're looking at case strength as your "biggest stumbling block" then you haven't even started thinking about heads or fuel injection yet.

"Sane and simple" and "one-off aircooled diesel cobbled together from gasser parts" are mutually exclusive terms, man.

[edit] I'm not trying to be mean, and I like the not-quite-mainstream thinking (I wouldn't call it out of the box, myself, as it has been done before. Just not on our scale, and by firms that engineered their parts rather than gathering and assembling), but I'm really objecting to the... casual optimism that doesn't seem to recognize the true enormity of the task at hand.

I mean yeah, I hope this succeeds, but I'm pretty confident it will never run, either because it gets left by the wayside or because it simply will not work.