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914 big engine build

Posted: Tue Aug 30, 2016 6:40 am
by Mikedrevguy
I'm beginning to compile the parts to build a big motor for RevWife's 914.
Looking at the AA type 4 crank - what avantage or pitfalls will there be staying with 2.0 rods vs going with type 1? How will the rod choices affect the deck?
What clearancing of a stock 914 2.0 case can I anticipate?
Any draw backs to going with an 82mm over a 78mm?
AA biral 96mm pistons/cylinders
Cam - 163/86b
Hpmx 44

What should be done to enhance cooling? Anything necessary?

This is her commuter car, fun weekend car, have fun on the 1/4 mile track.

Thoughts? Comments? Revisions..

: have stock 914 2.0 heads. What size valves would be best, were I to open them up?

Thanks in advance.
Mike
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Re: 914 big engine build

Posted: Tue Aug 30, 2016 11:19 am
by Piledriver
Welcome to the STF!

If going stroker on a t4, the shorter 78mm stroke and a smaller rod journal make it easier to clearance, as the rods do not clear the cam lobes as on a T1: t4 lobes are much wider due to wider cylinder spacing.
A reduced base circle cam may still be helpful, but a 78mm with the EMW 2.0 liter journal should clear most everything.

A 914 transmission is not recommended for drag racing--- 1st gear cannot take the abuse of a proper launch, its supported only on one end. Think of it as a 4 speed with a granny gear.

Re: 914 big engine build

Posted: Wed Aug 31, 2016 9:12 am
by Mikedrevguy
Thanks Piledriver. Am leaning more toward the smaller 78 stroke - just didn't want to discount anything out of hand without exploring.

any suggestion/recommendation for putting the 914 on the strip? Launch soft?
any other options?


Thanks,
Mike

Re: 914 big engine build

Posted: Wed Aug 31, 2016 10:45 am
by Piledriver
Autocross tracks can be ~1/4 mile :lol:

The 914 is ~ideal for that.

Re: 914 big engine build

Posted: Thu Sep 01, 2016 4:45 am
by sideshow
The autocross track is closer to you than a quarter mile track! Who cares about ones ability to drive in a straight line from a light?

If you lack the ability to make left and right turns the obvious solution to middle engine linkage/901 trans is a modern front engine automatic transmission. You would be on your own for a kit but it has been done (normally using both the subaru boxer/trans combo).

Re: 914 big engine build

Posted: Thu Sep 01, 2016 9:03 pm
by Piledriver
There is a SubaruGears ACVW engine<>Subaru trans adapter, I have been eyeballing it myself for my 914 when it gets the 2466.
(The adapter/flywheel combo seems a bit steep but I haven't priced Kennedys adapters in years)

Buidling a ~high HP capable VW or early Porsche trans would probably cost 5X what the subaru trans would, a converted 915 or G60 is just as rediculou$$S and likely no stronger. (I think they have to be run upside down?)

Most of the cost is a one time deal (adapter/flywheel/drive stubs) so even if you DID kill a Subaru trans, you still have all the conversion parts, so you just get another victim.

The Subaru automatic is a short, fat little sucker. Not sure specs or fitment, strength, or even if an adapter exists, but having a flexplate fabbed up won't cost any more than an adapter flywheel.

(I was eyeing Audi FWD transmissions in much the same way)