Big Bang Theory: Oettinger 2500E rebuild

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Re: Big Bang Theory: Oettinger 2500E rebuild

Post by silverbullet »

Engine now under offer, so time to finish it asap!
A bit of valve detail work after lapping the seats, easier to turn on the back-cut rather than muck about setting up the grinder...its a small detail but helps gas flow by getting rid of the step that lies behind the seat.
Inlets and exhausts get the same treatment.ImageImageImage

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Re: Big Bang Theory: Oettinger 2500E rebuild

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Now sold.

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Re: Big Bang Theory: Oettinger 2500E rebuild

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Finishing up: oil pump triple O-ringed, those Shadeks are always a bit undersize, so it helps the pump to
1. Not suck air from inside the case
2. Not leak, either back into the case or out into the world.
26mm gears as per original, no need to go mad as the 30mm over-work the oil and push temperatures up.ImageImageImage

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Big Bang Theory: Oettinger 2500E rebuild

Post by DoubleOSeven »

30mm oil pump; Devils Advocate bit: Are you not worried about a loss in pressure due to the high demands of the engine. The furthest rod bearing away needs it’s oil. Higher volume pump will help get the oil out to the bearings faster. Web extract, “The size of the gears or rotors determines the amount of oil a pump can move at any given rpm. Resistance to this movement creates the pressure. If a pump is not large enough to meet the demands of the engine, there will not be any pressure. Or if the demands of the engine are increased beyond the pumps capabilities (high revs) there will be a loss of oil pressure. This is where high volume pumps come in; they take care of any increased demands of the engine.”
Last edited by DoubleOSeven on 15 Mar 2019, 15:36, edited 1 time in total.
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Re: Big Bang Theory: Oettinger 2500E rebuild

Post by ash1293 »

DoubleOSeven wrote:Further still, being a 6 cylinder.


....is this not for the 4cyl Ottinger?
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Re: Big Bang Theory: Oettinger 2500E rebuild

Post by DoubleOSeven »

ash1293 wrote:
DoubleOSeven wrote:Further still, being a 6 cylinder.


....is this not for the 4cyl Ottinger?
Yup. Made the E D I T.


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Re: Big Bang Theory: Oettinger 2500E rebuild

Post by silverbullet »

Correct, this is the 4-cyl topic!

No oil pressure problems reported when using an oil cooler system.

I'm using a 30mm Type 1 (3-bolt) pump on the 6-cylinder. The original was a special, based on the Type 4 pump design but NLA

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Re: Big Bang Theory: Oettinger 2500E rebuild

Post by silverbullet »

A satisfying Saturday afternoon/evenings assembly work.
Full syncro spec details (labyrinth crank pulley seal, the correct dipstick tube and bracket) and all re-plated, plus a genuine aircon compressor bracket ;)
Nearly done.ImageImageImageImage

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Re: Big Bang Theory: Oettinger 2500E rebuild

Post by Cobra88 »

Nice spring compressor :ok
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Re: Big Bang Theory: Oettinger 2500E rebuild

Post by Bigjcc55 »

Starting to take shape Ian, and looking nice. I was going to ask about the syncro crank seal but no need to now. :ok

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Re: Big Bang Theory: Oettinger 2500E rebuild

Post by silverbullet »

Cobra88 wrote:Nice spring compressor :ok
Its a generic Aircooled cheap copy but works really well, a gift from a friend who was having a garage clear-out.
Its got a couple of mods:
I welded a pair of angled pins to the base for locating the head, plus wider pads to better support the valve heads.

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Re: Big Bang Theory: Oettinger 2500E rebuild

Post by silverbullet »

Details and general faffing. Crank pulley has been on and off about 6 times (and its a good tight one!) because the coolant transfer pipes needed a bit of a tweak to line up...its all a bit snug down there.
The engine bearer needed a tickle with the powerfile to clear the oil pump cover too, all done now.
350Nm achieved easily hanks to the big Teng and my diy copy locking tool.
Temporary oil pressure switches fitted in anticipation of a test run, the Gunzl pushrod guards need a bit of work too... just the flywheel to shim and she's oil tight!ImageImageImageImageImageImageImageImageImage

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Re: Big Bang Theory: Oettinger 2500E rebuild

Post by silverbullet »

Valve clearances set, 1.5 turns and a lot easier if you can turn the engine on its ear. I dont know how anyone manages to build a flat4 without the engine stand fixture tbh.
Note: the little /10/ stamped on the rocker post nuts. High tensile & copper plated to identify them, for good reason...ImageImage

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Re: Big Bang Theory: Oettinger 2500E rebuild

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That sealed spigot bearing...INA F-85265
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Re: Big Bang Theory: Oettinger 2500E rebuild

Post by silverbullet »

Flywheel shimmed to 0.08mm and the shop "test" exhaust hung. Not long untill first firing :)ImageImage

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