How does this guy do money shift ?

[beepbeep]

No way that is 4-speed 930 gearbox. Way too tight between gears. "winding out" 3:rd gear in 930 is Warp speed.

My guess is some sort of mashup with 915 gearbox. 915 is not strong enough to survive 930 torque without mods (billet sideplate, steel intermediate wall). Also, its shifter is quite sloppy, and even sloppier when shole gearbox is loaded with twice torque than original.

He either stripped gears or shifted into what he thought was 4:th (but tranny distorted shifter into 2:nd).

[beepbeep]

Originally Posted by javadog

It appears to be a 79 SC that the guy initially built into a 3.2 L short stroke, normally aspirated at first, then modified with some sort of aftermarket turbo set up.

OK, so aftermarket boosted N/A engine with high compression ratio and stock 915 tranny. That is risky build.

[masraum]

Originally Posted by javadog

There were two people in the car.

That would explain it.

[masraum]

I think it's a '76 911.

https://wheelwell.com/jayson-glanville

Top Mods on this Ride

Borg Warner Turbo

JE Pistons 98mm pistons

Porsche Main Bearings

Billy Boat Performance Exhaust Exhaust

Weltmeister Strut Tower Brace (Strut Bar)

Rennline Adjustable Pedal

Wevo Engine Mount (Motor Mount)

Porsche Tie Rod

Weltmeister Rear Sway Bar

[javadog]

Yeah, I’ve seen 76 and I’ve seen 79. It’s not a 76 dash in that thing, but the car could be a complete Frankenstein. The door panels are not from an SC…

[spuggy]

Originally Posted by wildthing

I don't understand why this happens. It's straight down.

Put 300+ HP through tired or stock mounts, they wind up pretty good. If you shift quickly enough, things are still more-or-less in the right/same place as they were last time.

Take too long finding the gear, and the mounts relax enough for the gate to move more than you might believe likely - like the width of a shift plane over. Then the stage is set for bad things to happen.

I note WEVO engine mounts - but no mention of trans mount. I run WEVO for both (blue on motor, black on trans); immediately/hugely obvious how much better controlled/much less weight moving around out back there is.

I've done a 4/1 shift instead of the intended 4/3 on a 930 with a very sloppy 915 and stock motor/trans mounts. Even without fully engaging clutch (eg zero top end damage), dropping a rod bolt was $$pendy.

Generally, would not recommend - although converting a running motor into a core is the perfect excuse to make it better...

[Jeff Higgins]

Play this game long enough and your day will come. It's inevitable.

The timing on my having caught this thread is incredible. I just had a similar experience. Pulling away from a stop, accelerating at a pretty mild rate, I heard (and felt through the shifter) a loud "bang" as I shifted into second, followed by the loudest "card in the spokes" "braaaap" sound imaginable. I stabbed the clutch in, pulled it into neutral, and did a pretty good verbal imitation of this poor guy. Except in my case, it was not a missed gear, and the motor kept running just fine. And once coasting in neutral, the noise went away...

So, how 'bout third? Let's try it... sounds fine. Fourth? No problem. Fifth? Sounds normal... So I drove home, about 50 miles, by skipping second. This was the Sunday before Christmas. My younger son helped me drop the motor that Tuesday, and I split the tranny off and ran it up to my good friend John Walker. He had it repaired by Thursday, I retrieved it on Monday, and my other son and I had it back together a couple of days later.

Here's what John found:



That's second gear. Broke two teeth clean off. It simply fatigued out, after 50 years. Granted, I'm twisting that poor old 915 harder than Porsche deemed appropriate, so these things can happen. Perhaps this is what happened to poor Jayson, and it wasn't operator error after all.

[spuggy]

Originally Posted by Jeff Higgins

Play this game long enough and your day will come. It's inevitable.

I'll see your 2 teeth, and raise you :



Driving to work, not even trying - I'd always babied 2nd too...

[Jeff Higgins]

Yikes - that's that turbo powa for you. Mine actually has a third tooth ready to fail, cracked about halfway through. Weird. Why second gear?

[masraum]

Originally Posted by Jeff Higgins

Play this game long enough and your day will come. It's inevitable.

The timing on my having caught this thread is incredible. I just had a similar experience. Pulling away from a stop, accelerating at a pretty mild rate, I heard (and felt through the shifter) a loud "bang" as I shifted into second, followed by the loudest "card in the spokes" "braaaap" sound imaginable. I stabbed the clutch in, pulled it into neutral, and did a pretty good verbal imitation of this poor guy. Except in my case, it was not a missed gear, and the motor kept running just fine. And once coasting in neutral, the noise went away...

So, how 'bout third? Let's try it... sounds fine. Fourth? No problem. Fifth? Sounds normal... So I drove home, about 50 miles, by skipping second. This was the Sunday before Christmas. My younger son helped me drop the motor that Tuesday, and I split the tranny off and ran it up to my good friend John Walker. He had it repaired by Thursday, I retrieved it on Monday, and my other son and I had it back together a couple of days later.

Here's what John found:



That's second gear. Broke two teeth clean off. It simply fatigued out, after 50 years. Granted, I'm twisting that poor old 915 harder than Porsche deemed appropriate, so these things can happen. Perhaps this is what happened to poor Jayson, and it wasn't operator error after all.

Ow, but at least the fix was relatively quick and easy.

[Rawknees'Turbo]

Regarding the turbo pooowwwaaahh 'v' a 915, Matt Monson posted a side-by-side pic comparing the gears in the 915 to those in a 930 box and the primary difference is in the width, or thickness of them - 930 gears are much beefier.

[ted]

I have missed a shift but so far I always catch it before I released the clutch.
Been lucky never hurt anything.

[A930Rocket]

Originally Posted by spuggy

I'll see your 2 teeth, and raise you :



Driving to work, not even trying - I'd always babied 2nd too...

I’ll wager a bunch of bent valves for your gear. This was the 4th to 1st money shift at Road Atlanta going into turn one at about 100 miles an hour in my 81 SC. Bent all the valves and ovaled the piston and cylinders.

[sugarwood]

Originally Posted by Jeff Higgins

Granted, I'm twisting that poor old 915 harder than Porsche deemed appropriate, .

How so ?

[Jeff Higgins]

Originally Posted by sugarwood

How so ?

3.0 liter motor with 11:1 compression, twin plugged (with Electromotive crank fire to light them), custom cam grind that John Dougherty and I worked out together (about the same lift as his DC80 or GE80, but less duration and different timing), MFI induction, some cursory head porting to match them up to the induction, and some other little tricks. Less peak horsepower than a 3.0 RSR motor (I don't rev it nearly as high), but significantly more torque. And both more horsepower and torque than the first gen turbo motors that engendered the four speed to begin with.

[spuggy]

Originally Posted by Jeff Higgins

Yikes - that's that turbo powa for you. Mine actually has a third tooth ready to fail, cracked about halfway through.

Yeh, you can see the damage to top of the fourth tooth in my picture - but what the picture doesn't show is the base of the fifth tooth cracked and shifted sideways as well... did exactly what yours did - I thought I'd cracked a head or the exhaust at first from the BRRRAAAAAAPPPP!!! noise...

Originally Posted by Jeff Higgins

Weird. Why second gear?

Dunno - I guess because no-one really hammers 1st too much? That was a tall gearset date-coded '72 that had been previously been in a rally car, and aged out about 4 decades previously, lol...

But it was awesome at PIR, coz you didn't drop to 1st for the sharp right hairpin, and would hold boost right up to the braking point for the sharp left without over-revving...

[spuggy]

Originally Posted by A930Rocket

I’ll wager a bunch of bent valves for your gear. This was the 4th to 1st money shift at Road Atlanta going into turn one at about 100 miles an hour in my 81 SC. Bent all the valves and ovaled the piston and cylinders.

Ouch!

My 4th -> 1st money shift (about 85MPH, by the time I let the clutch partially out) - still span well over 7K on stock 3.3 rod bolts (no idea why PO didn't use ARP).

The Porsche gods briefly allowed me the delusion that I'd dodged the bullet... 10 days later, just pottering along, rod bolt on #6 came undone/bearing span, oil pump filled up with ally swarf and tensioners collapsed...

But no top-end damage, other than minor scuffing on #6 skirt/bore.

[Jeff Higgins]

Originally Posted by spuggy

Yeh, you can see the damage to top of the fourth tooth in my picture - but what the picture doesn't show is the base of the fifth tooth cracked and shifted sideways as well... did exactly what yours did - I thought I'd cracked a head or the exhaust at first from the BRRRAAAAAAPPPP!!! noise...

At least now I'll recognize the "pre-braaaaap" warning noise. I drove it in that state for a couple of weeks. In denial... do I really hear something new? Naw... wait a minute, yes I do... naw... "braaaaap!!!"... hmmm... guess I did...

Originally Posted by spuggy

Dunno - I guess because no-one really hammers 1st too much? That was a tall gearset date-coded '72 that had been previously been in a rally car, and aged out about 4 decades previously, lol...

You just can't. Hammer first, that is. I would defy anyone to even get mine all the way to the floor before it's on the rev limiter. It happens just that fast. Pretty useless for anything more than pit puttering.

Originally Posted by spuggy

But it was awesome at PIR, coz you didn't drop to 1st for the sharp right hairpin, and would hold boost right up to the braking point for the sharp left without over-revving...

Yeah, I stay in second for that one too. Way different car, though, where I don't have to watch boost and have enough torque down that low to pull second through there, and enough "over rev" capability to not have to shift up until exiting that left and headed for the right hander leading to the rest of the straight. I'm using my full rev range to get through there, but it's nice to not have to shift until well on my way outa there.

[nzporsche944s2]

Reminds me of that thread "has anyone ever blown a tranny?"

That thread went downhill really quickly,....

[svandamme]

i'm confused.. short stroking AND turbo'ing an engine? why?
short stroking is good to make it a revvy engine.. But then boosting it?? on such an old design?
with a 915 tranny???

He was going to blow that thing up one way or another..