Engine/Driveline Tilt
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 6,128
Likes: 21
From: North Alabama
Engine/Driveline Tilt
Fitting my T5 up to my engine and since the trans mount is different, I want to get the angle correct. How do you measure? Can anyone tell me the degree of angle the engine sits in the frame if any? How critical is the alignment of the tailshaft of the tranny relative to the rearend yoke. I know u-joints make up for some of the disparity, but what is to much? Any help would be greatly appreciated! Gotta love this place! 
Safety Car
Joined: May 2001
Posts: 3,758
Likes: 3
From: Surrey
Had the same issue when I fitted an OD trans on mine. The way I checked it was to lay a straight edge across the car against the underside of the frame rails & then measure the distance between it & the lower edge of the yoke shaft. I then got Dallanex (also with an '81) to do the same & give me the distance. I've since lost the measurement but it's bound to be different between an '81 and yours :o 
edit: Found it: The lower edge of the yokes shaft at the point where it exits the tranny oil seal is exactly 3” above the lower edge of the frame.
edit: Found it: The lower edge of the yokes shaft at the point where it exits the tranny oil seal is exactly 3” above the lower edge of the frame.
Last edited by UKPaul; Mar 9, 2005 at 09:23 AM.
Race Director
Joined: Mar 2001
Posts: 11,322
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From: Living in the Hartland
I bought a magnetic angle finder at Lowes and measured the angle of the rear diff by removing the caps and putting the finder on the face of the yoke. You want to then set the trans at an equal BUT OPPOSITE angle of the diff pinion angle by putting the trans yoke in less the caps and measuring just like the rear diff. I could not get it 100% equal and opposite so I got it as high up in the tunnel as possible without hitting the yoke against the trans tunnel.
Finder looks like this:
Finder looks like this:
Last edited by Fevre; Mar 9, 2005 at 12:24 PM.
Safety Car
Joined: May 2001
Posts: 3,758
Likes: 3
From: Surrey
Originally Posted by Jclgodale3
ok...cool...but what "angle" should the entire assembly be? The engine and tranny pointed at the rear diff yoke? Level? 5 degree tilt towards the rear? etc...thanks
Melting Slicks
Joined: May 2001
Posts: 2,812
Likes: 4
From: Gig Harbor Wa
Driveshaft angle is not as big of a concern on our cars as it is on a live axle car. There is virtually no movement other than the mounts flexing a little between the rear end and the trans. On a live axle car the entire rear end moves and changes the angle at the u-joints. When I installed my trans, I eyeballed the angle and have had no vibration issues.
UKPaul hit it on the head. Just point the end of the trans toward the rear and call it good.
UKPaul hit it on the head. Just point the end of the trans toward the rear and call it good.
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Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
I did like Fevre. I measured the angle of the pinion and the angle of the transmission output shaft and made them equal and opposite.
I move the transmission as high up as possible in the tunnel, it only involves cutting a little around the hole to clear the tower but I push the transmission almost tight against the tunnel, make the proper transmission mount and once installed the transmission settles down from touching the tunnel.
You need the transmission as high as possible to cut down the error difference between the pinion and transmission.
Afterwards I adjust the pinion angle to match the transmission.
We also have a problem with alignment between the crank, the transmission and the pinon. I addressed this seperately.
I move the transmission as high up as possible in the tunnel, it only involves cutting a little around the hole to clear the tower but I push the transmission almost tight against the tunnel, make the proper transmission mount and once installed the transmission settles down from touching the tunnel.
You need the transmission as high as possible to cut down the error difference between the pinion and transmission.
Afterwards I adjust the pinion angle to match the transmission.
We also have a problem with alignment between the crank, the transmission and the pinon. I addressed this seperately.