Squishy testing halted..... dyno failure again!

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue Aug 10, 2004 6:45 pm

Today while trying to wring all the power out of the Squishy engine, this happened.... I have been plagued with dyno issues like this for 6 months, and already wasted a 6,000 buck waterbrake earlier in the year.

Today, we were running hard in the upper RPM range (around 6-7500 RPM) and I felt a weird vibe that feels too familiar. I felt it right before we exploded the last shaft.

Brent went in, and inspected the shaft and said, "We're done dynoing today".... Then he said "You gotta see this"....

The shaft split right up the middle, from the yoke up the shaft, its actually in two pieces but didn't come apart! I noticed thet the crack went right through the center of the grease fitting, and that it was gone... Then I looked up and saw where it went through the ceiling! Look at the bottom pic..

Keep in mind that this shaft is rated at 1500HP from Stuska, and they told me the only thing that breaks them like this is when people dyno Diesel engines! The low revs and high torque really work on things... Guess we have had too many 200 lb/ft animals on the dyno lately!

I'll have a new shaft on Thursday, but damn is that an expensive little jewel! If that shaft would have split at 6,000+ RPM, it would have wiped out the entire dyno, and probably the engine as well... Last time this happened a shaft went through my tool box!

HOLY COW BATMAN!! Thats a grease fitting!

Glenn · Post by **Glenn** » Tue Aug 10, 2004 6:59 pm

Jeez...

Maybe you should build something that will stress the dyno less... like a honda engine.

When racers say "If you're not breaking parts, you're not trying hard enough", i don't think this is what they were reffering to.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue Aug 10, 2004 7:00 pm

LOL, Yep.. Torque does this, especially at low revs... Then the high revs make it show up.

We have been checking the shaft between every engine with liquid penetrant to see if we can find any cracks, and nothing showed up...

69bug · Post by **69bug** » Tue Aug 10, 2004 7:07 pm

i heard that on high horsepower and torque engines (like muslce cars that are rear wheel drive...) it might be a good idea to use a solid yoke instead of one with a grease fitting

they say the greas fitting drilled through it reduces stregnth a LOT...

the only compromise is quicker wear...so it needs to be replaced more often

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue Aug 10, 2004 7:11 pm

Yep, this is a half shaft from a Vette, that Stuska has modified..

My old one had the fitting removed and welded shut, this one did not, and they recommended that I leave it open...

I am changing the entire set up this time, and having the shaft cryoed.

1967Fastback · Post by **1967Fastback** » Tue Aug 10, 2004 7:20 pm

mharney · Post by **mharney** » Tue Aug 10, 2004 7:49 pm

Come on now...

We're not talking about fire breathing beasts here.. we are talking 200 HP VW engines.. There must be another player in this equation. If this is what happens with these, what the hell do they do about big V8s?

Sux Jake.. Hope you get it going again soon. I'm interested in the torque curve.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue Aug 10, 2004 8:00 pm

Torque curve is FLAT, more torque than I have ever seen from a TI before, and it was not even close to being dialed in.

I don't see how anyone would ever get one of these engines dialed in withiout a dyno. I have never seen such funky tuning in all my dyno days, it doesn't want any timing, nor does it want any gas......

It definately takes some getting used to, but we are getting it.

mharney · Post by **mharney** » Tue Aug 10, 2004 8:01 pm

Hell, I'll probably have to send mine to you for dyno tuning. LOL!

NO_H2O · Post by **NO_H2O** » Tue Aug 10, 2004 8:11 pm

Looks like it started at a 90 deg edge again. Looks like you will have to radius all the crisp edges of the drive train parts and re-bal. everything.
That is after you replace the drive shaft.
Sharp edges KILL.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue Aug 10, 2004 8:16 pm

Yep, stress risers for sure. Only thing is that they balance the shaft before they send it to me, and my balancer cannot rebalance it when I'm done knocking the edges off...

Mharney, if you want to send it to me, thats cool.

brianwheelies · Post by **brianwheelies** » Tue Aug 10, 2004 8:21 pm

Jake, your motors must be mean if your breaking dynos like this

.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue Aug 10, 2004 8:25 pm

There has to be another issue... The shaft is rated for 1500HP! All geometry is correct, everything is balanced-

I'm going to chill out with the load valve and test at a rising rate now, instead of a descending rate, that should make for less stress, but its harder to get good solid numbers.

EASY RIDER · Post by **EASY RIDER** » Tue Aug 10, 2004 8:27 pm

Glad it did not break when there was some sap under the engine in the dark with a digi cam.

Hey, I'm humbled for sure.

Bert

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue Aug 10, 2004 8:33 pm

Hell, 5 minutes before this Brent was 2 feet from it at 3500RPM!