Another F1A-94 build

[Whitedevil95]

Wow thats some strong carbon fiber right there!

Sponsored

 

[QBailey]

Wow thats some strong carbon fiber right there!

Our best guess is that one of the clips came out of the flange and the U-joint worked its way out. Then it just self destructed from there.

 

[QBailey]

I reached out to Ben at Fat fab and he had never seen one fail at all, much less like this one did. So despite the bad taste left by the last one I decided to just let modern driveline warranty it. They wanted the broken parts so they could investigate why it possibly failed but they couldn’t figure it out either. They did decide to use a different flange adapter this time, so as far as I know this might be the first one for a T56 s550 like this.

 

[80FoxCoupe]

That 6 bolt pinion flange is the standard unit. The 4bolt deal you had on it that broke is the odd unit.

 

[80FoxCoupe]

The 4 bolt flange is likely a early production piece. All the qa1 carbon ds I've had and seen all had the 6 bolt. U joint failure is a real thing as I have suffered that at one point. It's Def something you want to keep an eye on. With a one piece ds, the angle on each side needs to be equal and minimal. If not, a certain level of vibration occurs as the shaft or pinion yoke oscillates in speed as one of the yoke/flange angles increase. The u joints usually take a beating.

 

[80FoxCoupe]

@QBailey you may be well versed in ds angles and all that, but for those with limited experience here is a good vid about it.

 

[QBailey]

The 4 bolt flange is likely a early production piece. All the qa1 carbon ds I've had and seen all had the 6 bolt. U joint failure is a real thing as I have suffered that at one point. It's Def something you want to keep an eye on. With a one piece ds, the angle on each side needs to be equal and minimal. If not, a certain level of vibration occurs as the shaft or pinion yoke oscillates in speed as one of the yoke/flange angles increase. The u joints usually take a beating.

Really? The 4 bolt one actually had two machined socket head cap screws that acted as alignment dowels on the under side of the flange and then the 4 bolts you could see. That one was bought late last year from modern driveline.

As far as I understand the only way to adjust pinion angle on these cars would be to shim the trans up or down. Presently it has less than 1* of difference between the pinion and the back of the trans. Same as before, and zero vibration.

 

[80FoxCoupe]

Really? The 4 bolt one actually had two machined socket head cap screws that acted as alignment dowels on the under side of the flange and then the 4 bolts you could see. That one was bought late last year from modern driveline.

As far as I understand the only way to adjust pinion angle on these cars would be to shim the trans up or down. Presently it has less than 1* of difference between the pinion and the back of the trans. Same as before, and zero vibration.

Interesting on the 4bolt flange. I'm sure it is plenty strong. Just be sure to split the angle differences equally on both ends if possible. You can also shim the rear cradle downward if needed.

 

[QBailey]

Todays results. Car is still on our pump E70 that we have here in Oklahoma. More to come tomorrow. Yes those are my old N/A graphs for reference

 

[turnswrench]

niiiice

 

[QBailey]

Nothing but an uphill battle today. Broke the belt for the 4” pulley on the first rip. Replaced it with a continental belt because that’s all I could get, made a rip to 8k and it puked coolant out of the degass bottle.

We thought for sure we must have lifted a head. We couldn’t believe it since I had the block drilled for 1/2” head studs, that are torqued to 125lb/ft. I was just sick, nothing I could do but verify with a leak down.

All cylinders came back 5% or less, awesome! Went ahead and did a compression test while I had the plugs out, all in the 150/160psi range.

The best conclusion we could come up with was possible this was self inflicted, due to I rerouted all coolant lines with -10. It’s slightly smaller than what was there factory, maybe I should have use -12. And secondly the procharger degass only has a 16psi cap, whereas all the factory ones have a 21psi cap.

Made great power though.

 

[80FoxCoupe]

Good power. Keep an eye on that coolant issue. If it's hard to start, have more water vapor coming from one exhaust pipe or have a odd looking spark plug or two you got a head lifting. I've been through it a bunch.

 

[QBailey]

Good power. Keep an eye on that coolant issue. If it's hard to start, have more water vapor coming from one exhaust pipe or have a odd looking spark plug or two you got a head lifting. I've been through it a bunch.

Watching it like a hawk. All the plugs looked great after this incident. Once I put everything back together it fired right up and drove like it never happened. I’m thinking I could have possibly over-serviced the cooling system when I first fired the car. Looked like it puked maybe 1/4-1/2 gallon of fluid, I only added a cup full back to top it off. I would think it would have done the same thing during any of the previous pulls. Very odd.

 

[QBailey]

Here’s a view of how much condensation build up there is in the exhaust. This was NOT during the pull with the coolant issue.

Sponsored