gtpvette

iTrader: (2)

Working on a swap,, putting a 2015 LFX V6 into my Scion FRS. I'm trying to get the mounts finished up and I've run into a driveshaft angle issue.

When setting the transmission angle (1.2 down) to match the pinion (1 up) the top of the transmission is so close to the transmission tunnel it creates issues for the shifter. As a sidebar driveshaft angle is about 3.6 down with this setup. If I drop the transmission angle to say 2.5 - 3 down a lot of the shifter issues go away. Of course my driveline angles are way out of wack at this point.

I've seen a few threads regarding using a CV at the transmission end when the angles are less than perfect and I'm certainly OK with that. My questions concerns the pinion end. With the pinion nose 1 degree up and the driveshaft maybe 3 degrees down,,, will I get vibration???

Papermachtech

We need the drive line angle to do the calculations.

gtpvette

iTrader: (2)

transmission angle (1.2 down) to match the pinion (1 up) , driveshaft angle is about 3.6 down

Is there more than these needed??? I want to drop the transmission to about 2.5-3 down which will change the driveshaft angle slightly. Is that needed exactly??

1964SS

iTrader: (1)

A CV on the transmission end will work great. You only get vibration if your opposing u joint angles do not match up correctly and with a CV on one end the problem is eliminated. CV joints are larger then u joints so you may have an issue fitting one up close in the tunnel.

Michael Yount

iTrader: (1)

If there's a way to raise the pinion to match revised engine/tranny angle (3 degrees or so) seems to me that will reduce the ujoint angles and make everything really happy. But if moving the IRS lump around is problematic - as 64 says above, CV on one end should resolve. Tech line at The Driveshaft Shop in Salisbury, NC have always been very helpful in helping me think through questions/solutions like this.

G Atsma

I would call them to see what their angle (sorry, could NOT resist...) on this might be....

87c10

Set you pinion on the same parallel line as the center line of the crank. ..don't worry about u joint angles , your 2 wheel drive whatever isn't lifted or lowered enough to kill them.look at all the lifted 4x4s. "( mall crawlers)" NOT killing their u joints

Michael Yount

iTrader: (1)

IRS on his car -- adjusting the pinion angle is, I suspect, not easy.

Papermachtech

Check this you-tube video out, explains it better than I can.

gtpvette

iTrader: (2)

Thanks guys. As for adjusting the angle of the pinion. Sort of doable. There are a pair of vertical bushings on either side or the front of the diff. There is maybe the better part of an inch of rubber on top. I suspect I might be able to grind some off to raise the front of the pinion some.

I've been bantering some email with the DSS. Nice guys and very helpful. Just heard back and they think a CV will do the trick. They seem to think that the pinion U-joint should be OK as total operating angle is less than 3. I think I'll go with the CV driveshaft to start. If there are any issues then try to adjust the pinion angle.

Michael Yount

iTrader: (1)

No, no, no. Adjust pinion angle first. May not need the new driveshaft/CV.

gtpvette

iTrader: (2)

OK, OK,,LOL. This is a swap and the old driveshaft wont work so a new one is needed either way. Thanks for your thoughts.

Michael Yount

iTrader: (1)

My bad, bad, bad. In event CV-jointless DS cheaper....so, whichever approach works for you! I could understand not wanting to futz with the diff if you don't have to. Somehow in my head, you already had a u-jointed driveshaft - just trying to sort out the angles.

87c10

When having a drive shaft made get it with the biggest u joints possible , like 1350 series .

Pop N Wood

iTrader: (1)

Can you lower the front mounts of the motor? Would change your trans angle without needing to raise the tail.

Pretty common mod on 240z's is to drill out the IRS mount bushings to level out the diff. In many respects IRS rears offer better adjustments in this regard than an straight axle.

Didn't realize CV joints had the same operating angle restrictions as U joints. U joints need to be matched in angle front and rear to cancel out vibration and should limit the overall angle to extend life. But CV's front and rear should get by both problems??

Michael Yount

iTrader: (1)

Might want to re-read his initial post -- he need to lower tranny because it's interfering with tunnel. Lowering front of engine will raise the rear of the tranny - makes problem worse. Pretty sure the CV joints will handle greater angle than U-joint - hence the possible solution.

Pop N Wood

iTrader: (1)

What I wrote will work. Think it out.

Michael Yount

iTrader: (1)

I did think it out before I wrote it - which is why I replied the way Ia did. If you leave the rear tranny mount alone, and lower the engine mount, it moves the engine/tranny angle in the opposite direction of what he needs for clearance AND creates a mismatch between engine/tranny and pinion angles.

Now, if he lowers both ends the same amount --- engine and tranny ---- the same amount, he maintains his match between that and the pinion AND reduces his ujoint angles.

Pop N Wood

iTrader: (1)

Winner winner, chicken dinner!!!

Michael Yount

iTrader: (1)

He didn't need to change his trans angle -- there's already a close enough match between it and his pinion. He needed clearance between tranny and tunnel. So perhaps if you'd written -- "Can you lower the engine/tranny FRONT AND REAR by the same amount? This would give you the tranny clearance you need without creating other driveline angle issues." -- we'd have known what you meant, versus what you said.