The T3200E thread

[silverbullet]

Loafing around at dog agility classes (I'm strictly there for moral support) is also good thinking time

The extra time also helps for unnoticed horrors to catch the eye: a casting bleb high up in the timing gear housing, about the size of ¼ peanut, was held on by less than 1mm² and took the slightest of taps to detach

[silverbullet]

Here's the offending bleb and where it was lurking (right next to where I had chosen to relocate the dipstick, that tiny white dot by the file handle is where it was attached)
I dont want to think about the damage it could have done.

[silverbullet]

I've had a bit of a break from this, busy at work and cultivating new interests but it was time to get back on it.
Sump baffle plate prototyping.

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Getting my head aroond the problem now.

All wbx engines have a quite shallow sump, which means that even modest cornering or braking/acceleration forces (and therefore tilt and pitch angles when offroading) cause the oil to surge to either the ends and/or into the rocker boxes, via the pushrod tubes and their drain ports. This can cause the oil pickup to be exposed to the air in the crankcase, the pump then sucks in air and oil pressure fluctuates. Not good for bearing life!

The wbx6 makes this worse by having a sump 50% longer, increasing the risk of the oil pickup becoming exposed.

So...it needs some decent oil control in form of (1) a close fitting horizontal baffle to restrict oil surge into the rocker boxes and (2) hinged gates to keep the oil around the pickup, which also needs some work:

Because of the wbx6 origins and Oettinger being a bit lazy, the oil pickup is offset towards the back of the sump, not in the middle.

The original had a feeble baffle plate tacked to it, better to start again with an extended pipe:

[silverbullet]

Back to hardboard and cardboard!

The big idea is to divide the sump into nine compartments of about 600-700cc, using the existing cast-in baffles and augmenting them with a pair of longitudinal steel plates (each with three gates made from hinges with the holes welded up to control side to side surge) as well as another pair of gates controlling fore/aft surge.

Basically, a set of one-way flaps that encourage the oil towards the pickup at all times.

The horizontal baffle will have a large hole in the middle to direct all dtain-down oil directly to the pickup, this will also provide a large flat surface for the oil to deaerate (a good thing) at the running level, which should be around the mid-way level with a full sump, because all running engines "hold" a certain volume of oil in the rocker boxes, galleries etc as well as that which forms a sort of cloud caught up around the rotating crank assembly.



Hopefully all these measures will result in stable oil pressures regatdless if the driving conditions or terrain. Can't be any worse than no baffling at all...

[silverbullet]

AFM part number research on goggle led me to the Finnish Wikipedia page for the T3, which now has a raft of Oettinger history and part number data

https://fi.m.wikipedia.org/wiki/Volkswa ... orter_(T3)

[silverbullet]

I found another 12 vane impellor in a used recent-ish aftermarket early waterpump. The spindle/bearing is perfect and has a grease hole, so that will give me a spare once I have ported the pump body

[Cecil]

I noticed that the fire rings are 2.5/3.7 items for 98mm pistons, so it seemed like a good opportunity to cc the combustion chambers.
24cc with the 98 rings, 22cc with the correct 94mm rings.
So it was always down on compression, even worse than a standard MV!
So I can afford to tickle the chambers a little to improve the low-lift flow and not lose out on compression (AMC heads are 23cc and when combined with DJ pistons return a true 10:1 SCR)
The ports are also a different form to a wbx4 and the valve guides are longer too.

Sent from my S60 using Tapatalk

Bear with me while I type very slowly!
Your volume measurement with the syringe shows a 2 cc difference between using a 98 mm fire ring against using a 94 mm fire ring .I tried to calculate what difference to expect using pye etc .Not knowing the fire ring thickness I guessed 0.8 mm and got a result of  E D I T 0.49cc . Anywhere near correct?
To do my calculation I imagined cutting a strip of metal the  circumference of the ring x 2 mm x .8 mm from the inside diameter of a 3.2 litre ring ! ( probably a silly / lazy way of going about it)
Have I uncovered an error or have I misunderstood the difference between a 3.2 and a 3.7 fire ring? Or am I totally out of my depth questioning your measurements!
E D I T 937 Carrera measured one at 0.84 mm thickness!(works out at 0.52 cc)
 

[silverbullet]

I can't remember as it was a good while ago

The rings are 1.2mm, could have been a typo but its all about what's measured and the spark plugs being used.

The original Oettinger brochures list the 3.2S as having a SCR of 9.8:1 but with DJ pistons marked as 10.3:1 the reality is somewhere in between.

[Cecil]

1.2 mm  thickness works out to 0.74 cc by my calculations , so still nothing like 2 cc.
Seems there is something wrong or typo  in the figures you posted.

[silverbullet]

A little light exhaust valve guide replacement, as one was loose. I went for second oversize and they took some belting in, so the Jaguar wire clip mod is somewhat superfluous.

Always get the heads hot degreased and the exhaust ports decarbonized before attempting this sort of work and remove all studs, I left the rocker studs in place and one seeped*

I preheated the heads overnight at a low temp (80°C ish) then put them into the top oven for a few hours to get them hotter, probably 160-170°C

*It made the house a bit whiffy...

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Two steps forward, one step back.
The bronze timing wheel that I commissioned was cut to the wrong profile and had far too much backlash, about 0.3mm...so I have decided to chalk that up to experience and try again.
Thankfully I came by a vgc -3 aluminium gear, tried it on the spare cam and its spot on, so now I have a good master for the gear cutters to work to.

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Two blank gears in AB2

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At long last, I might just have some timing gears with acceptable running clearances. The tooth form had to be changed to something that could be made with production tooling, so they are unique to this application. I will hopefully never need the spare!

[silverbullet]

I wanted zero backlash and I have got exactly that! One gear is cut a gnat's smaller than the other and that one gives me just enough clearance to let me rotate the cam withing the gear. Couldn't have turned out better.
Thank you All Gear Services of Bracknell.