T4 94s Pistons in T1 94 Cylinders

Pillow · Post by **Pillow** » Mon Aug 15, 2005 8:18 pm

Here is a thought of mine for a mild Oxy.

T1 94 cylinders
T4 914 2.0 (flat top) 94s with 24mm wrist pins
Stock 76mm crank
Stock Wasser rods

On paper I have not roughed in the wrist pin height to figure CR or anything like that, but rumor has it that this is a good combo.

Probably a simple question, but one I have not heard the details on.

This would be for a heavy '66 Split Westi so I am not concerned that the T5 rods are heavier than T1 units.

Thanks,

Pillow · Post by **Pillow** » Tue Aug 16, 2005 6:30 pm

In doing more research it seems that the Euro T4 94s (flat tops) are pretty pricey, maybe a stupid idea...

JEs are the way to go at that price, or of course just plain old T1 Mahle/AA stuff.

Post by **Tom Notch** » Tue Aug 16, 2005 6:53 pm

just have to find some good used ones.

or know someone who may

I'd just use T1 Cimas or the new AA pistons as they are really sweet. Then bush the rod for 22mm.

Post by **Piledriver** » Wed Aug 17, 2005 5:50 pm

The AA piston crowns are .200 thick, with an extra .100+ in (IIRC) for valve reliefs.

I want to say the pin height of the T4 2.0 pistons is... 36mm... REAL close to that anyway.

on a WBX, If you went with the 15cc dish bus ones and 1mm deck, the CR would be ~15:1, but you would have EXCELLENT squish, and it's far easier to REDUCE CR than increase it...
You'd have to modify the pistons anyway for valve reliefs, so at that point you're probably pushing ~12.5:1, mostly opening up the ex side to bias the burn there...

Just about perfect for a Miller Cycle cam and a blower.
(You'd thing I had been thinking about doing this or something

)

Oh, wait. you want an OXY... AA Bs or Mahle Bs then. You can get a 2mm pin height adjustment just about for free BTW... when you have the rods bushed down, have them offset as needed.

The T4 914 std pistons are 7cc dishes. I don't know your heads combustion chamber size etc... But they MIGHT be usable.

Pillow · Post by **Pillow** » Wed Aug 17, 2005 8:23 pm

Okay Pile, you have me thinking again! Bastage

With even the Bus T4 pistons with a dish that would provide a good squish if the CR was bumped up a bit. Hmmm. Plus the Bus pistons are easy to find to play with.

As for CR the T1 94 cylinders need trimmed anyway for an oxy so it can be set at any height desired, which is great.

... Someone needs to buy my FS stuff in the T1 FS area so I can fund this project along with the CIS FI

hee hee

Later,

beelzibus · Post by **beelzibus** » Wed Sep 14, 2005 12:10 pm

What about using the WBX 2.1 pistons in T1 barrels? Thats what I was thinking,Same lines as above,heavy camping bus,stock 2.1 crank,and rods.Lowish CR,maybe a turbo?

Post by **Piledriver** » Wed Sep 14, 2005 11:48 pm

WBX pistons have ~35cc dishes---chambers...
IOW, the "combustion chamber" is mostly in the piston.

If you are using WBX heads that's a feature tho. (~15cc in the head, basically the edges of the valve seats are flush with the deck, minus the 7 degree valve angle. Room for a plug...)

beelzibus · Post by **beelzibus** » Thu Sep 15, 2005 12:05 am

Er in laymans terms?

Post by **Piledriver** » Thu Sep 15, 2005 2:31 am

beelzibus wrote:Er in laymans terms?

If you use t1 heads with std combustion chambers (45-55CC, depending on flycut etc) WBX pistons will be perfect if you are shooting for a 5-6:1 CR.
(You don't want that)

beelzibus · Post by **beelzibus** » Fri Sep 16, 2005 8:45 am

Ah right,so the WBX pistons have pockets and therefore the overall CR would be too low.
OK thanks.
Is that all 2.1 pistons or are there differences in Euro and US spec?

Post by **Piledriver** » Fri Sep 16, 2005 9:49 am

The DJ Euro spec ones are around 30cc... 10.5:1 CR with Wasser heads.
MV, 35CC, ~9:1.
GoWesty sells nice Wisecos custom made for the WBX, around stock CR.
With flattops and no chamber mods, IIRC it works out to ~22:1

MarcotheTurboSteamEngines had Oliver Knuth (I always spell his name wrong) put 5mm shorter valves (recessed valve seats 5mm) and had chambers machined in...

beelzibus · Post by **beelzibus** » Fri Sep 16, 2005 10:05 am

Well thanks for the info,its kinda screwed up part of my plan a little,I'm going the Oxyboxer route,and thought that perhaps the DJ base that i'm using would have a reasonably high CR,and if I used its pistons in T1 aftermarket barrels,I might not have been far wrong,I hadn't considered quite such a difference in design between the aircooled head and the WBX head.Ah well back to the drawing board then.

Post by **Piledriver** » Fri Sep 16, 2005 11:01 pm

Y'a know, a MV spec 2110 (stock) with H-beams, cam, and a blower/turbo should be good for >300HP++... Been done, albeit not with the stock injection.

Something with a Miller cycle cam and a blower, a bit more compression (like ~11:1) should make ~130HP and get 50 MPG++ in a light car. (some engineering required)

I considered gettin AA forged pistons (94s) and doing my own dishes... The crowns are quite thick, ~.200, and .300 thick at the valve reliefs... Bias it all towards the exhaust and you have (almost) instant squishies. The piston pin bush resize gives you a possible ~2mm to play with offset to set deck.

I keep looking at that whole scenario every time I try budgeting a hipo T4 build for my 914.

A WBX bolts right in... Tried it. Flywheel and all just works.
I'm using a 228mm flywheel in the 914 for the last ~50K miles.
Theres even room for a Vanagon radiator in the spare tire space. (verified that)
I have a spare...

If it wasn't a 914 LE, the Sawzall would have been used by now.

Passatman · Post by **Passatman** » Wed Mar 15, 2006 11:59 pm

Hi all found this post here very interesting as me and a couple friends here in Jamaica was talking about doing something close to porsche 959 engine we have alot ( or use to have alot ) of waterboxer engines lying around, after these engine cut the studs the owners will throw the engines out. I mean literally through the engines away in the dump, we however still can find some. The plan was to use the mv code engine with type1 sleeves, water cooled type5 heads, and possibly bus type4 pistons could be good for turbo. As i see it this combo would make a serious reliable 2.1ltr monter. Has anyone tried this before.

Post by **Piledriver** » Thu Mar 16, 2006 10:37 am

You could probably just use the MV pistons... 94mm as well