Ultima/G50 gearchange question please
Discussion
Forgive me intruding onto this site with a non Ultima question:
I have built for hillclimb competition a T 492 Lola mid engines '2' seater Sports racer with a Porsche 911 flat 6 and gearbox (915 type, predecessor to the G50)
http://www.youtube.com/watch?v=D2gfipR4TOM
It has/had difficult gearchange issues which after it's first race a few weeks ago, I'm working on.
I have found pics on here of the way Ultima have done it, and i'm copying it right now.
Ordered all the parts etc for my version.
Question:
Have you had any probs with the Ultima design, esp the threaded adjuster close to the box input shaft for the change?
Does the clamp nut come loose etc at all in the heat of the battle so to speak?
From one video clip I've watched, the change is very clen and posative, but that might have more to do with the box itself than the linkage.
Hope you can comment or show pics please.
Need to finish the shift linkage in the next week.
I have built for hillclimb competition a T 492 Lola mid engines '2' seater Sports racer with a Porsche 911 flat 6 and gearbox (915 type, predecessor to the G50)
http://www.youtube.com/watch?v=D2gfipR4TOM
It has/had difficult gearchange issues which after it's first race a few weeks ago, I'm working on.
I have found pics on here of the way Ultima have done it, and i'm copying it right now.
Ordered all the parts etc for my version.
Question:
Have you had any probs with the Ultima design, esp the threaded adjuster close to the box input shaft for the change?
Does the clamp nut come loose etc at all in the heat of the battle so to speak?
From one video clip I've watched, the change is very clen and posative, but that might have more to do with the box itself than the linkage.
Hope you can comment or show pics please.
Need to finish the shift linkage in the next week.
Edited by 911hillclimber on Monday 27th July 07:18
Nice looking beastie you have there - is it a scratch build or a kit?
What is the specific shifter problem?
The side-to-side gate works by twisting the rod.
Forward to rear obviously by pushing and pulling the rod.
Generally, a shifting problem results from getting a little bit of twisting motion in the rods.
You will notice at the transaxle end, the range of in-out movement (say from 1st to 2nd) is much more than the range of rotation required to go across the neutral gate.
Because of this, a very slight twisting will screw up the gate, usually evidenced by a fanned shaped gate rather than a square one.
eg: 1st/3rd are further apart than 2nd/4th.
If the knuckles in the uni joints do not align they can induce twisting motion when you go forward > backwards.
The other problem could be a little bending somewhere, or too tight an angle between 2 rods (which leads to bending > which leads to twisting)
Take some photos of your setup and post them.
What is the specific shifter problem?
The side-to-side gate works by twisting the rod.
Forward to rear obviously by pushing and pulling the rod.
Generally, a shifting problem results from getting a little bit of twisting motion in the rods.
You will notice at the transaxle end, the range of in-out movement (say from 1st to 2nd) is much more than the range of rotation required to go across the neutral gate.
Because of this, a very slight twisting will screw up the gate, usually evidenced by a fanned shaped gate rather than a square one.
eg: 1st/3rd are further apart than 2nd/4th.
If the knuckles in the uni joints do not align they can induce twisting motion when you go forward > backwards.
The other problem could be a little bending somewhere, or too tight an angle between 2 rods (which leads to bending > which leads to twisting)
Take some photos of your setup and post them.
911hillclimber said:
Forgive me intruding onto this site with a non Ultima question:
Forgiven911hillclimber said:
Have you had any probs with the Ultima design, esp the threaded adjuster close to the box input shaft for the change?
Does the clamp nut come loose etc at all in the heat of the battle so to speak?
Mine's not moved in five years and 15,000 miles so no problem with the adjuster. The only thing I do is take an oil can to the point where the shaft slides through the rose joints that are the rod mounts.Does the clamp nut come loose etc at all in the heat of the battle so to speak?
Steve
Thanks for the replies both.
The Radical lads do not appreciate interruptions.
The car is a real lola T 492 from 1978 which had a Pinto engine and Hewland Mk9 gearbox when new. I wanted a big engined car for the hills so this roller got the 911 engine! I wanted to be different in Sports Libre class over 2000cc.
I have the original Lola design fron the lever to the engine side of the rear bulk head.
This is one long straight rod with a helicopter UJ at the end. From there it goes to a sliding rose joint and another heli UJ, again almost straight with the first rod.
Then it goes bad..
The second rod stops at the rear chassis just by the drive shafts, and then to the box but at nearly 40 degs! Thus a good shove fore/aft gives a high side component force equal-ish to the fore aft force and things can bind a bit.
With the 'Ultima' design I am copying, this third rod will be routed to allow the alignment to be a more civilised 15 degs.
I plan to have the threaded stud as the Ultima design to allow all the adjustments to get the 1st/2nd and to 3rd/4th by the UJ twist action. The box is a 5 speeder and has no well defined gate 3rd to 4th so I will block the travel of the box's input shaft connection lever from 5th/Reverse.
Don't have the nerve yet to use 5th on the track....
With the original/just-removed set-up the gears could be had (1/2/3/4th) static, but when charging up the hill it blocks going into 3rd from 2nd about 8 times in 10 trys.
I expect the new route to reduce further the lost motion in the play (all UJ's are tight)and the lever is in brass bushes close to transision fit with their pivot bolts.
The engine and box are near solid mounted in thin wall poly bushes and on very ridgid mounts.
You leave lots of time behind every change to 3rd, but when you do get it it is ballistic (the car weighs 559Kg.)
http://www.youtube.com/watch?v=f4Smh2qOy7w&fea...
http://www.youtube.com/watch?v=qCROpzPOQ6Y&fea...
http://www.youtube.com/watch?v=qCROpzPOQ6Y&fea...
The Radical lads do not appreciate interruptions.
The car is a real lola T 492 from 1978 which had a Pinto engine and Hewland Mk9 gearbox when new. I wanted a big engined car for the hills so this roller got the 911 engine! I wanted to be different in Sports Libre class over 2000cc.
I have the original Lola design fron the lever to the engine side of the rear bulk head.
This is one long straight rod with a helicopter UJ at the end. From there it goes to a sliding rose joint and another heli UJ, again almost straight with the first rod.
Then it goes bad..
The second rod stops at the rear chassis just by the drive shafts, and then to the box but at nearly 40 degs! Thus a good shove fore/aft gives a high side component force equal-ish to the fore aft force and things can bind a bit.
With the 'Ultima' design I am copying, this third rod will be routed to allow the alignment to be a more civilised 15 degs.
I plan to have the threaded stud as the Ultima design to allow all the adjustments to get the 1st/2nd and to 3rd/4th by the UJ twist action. The box is a 5 speeder and has no well defined gate 3rd to 4th so I will block the travel of the box's input shaft connection lever from 5th/Reverse.
Don't have the nerve yet to use 5th on the track....
With the original/just-removed set-up the gears could be had (1/2/3/4th) static, but when charging up the hill it blocks going into 3rd from 2nd about 8 times in 10 trys.
I expect the new route to reduce further the lost motion in the play (all UJ's are tight)and the lever is in brass bushes close to transision fit with their pivot bolts.
The engine and box are near solid mounted in thin wall poly bushes and on very ridgid mounts.
You leave lots of time behind every change to 3rd, but when you do get it it is ballistic (the car weighs 559Kg.)
http://www.youtube.com/watch?v=f4Smh2qOy7w&fea...
http://www.youtube.com/watch?v=qCROpzPOQ6Y&fea...
http://www.youtube.com/watch?v=qCROpzPOQ6Y&fea...
Edited by 911hillclimber on Monday 27th July 21:00
Edited by 911hillclimber on Monday 27th July 21:04
Edited by 911hillclimber on Monday 27th July 21:06
Edited by 911hillclimber on Monday 27th July 21:08
Edited by 911hillclimber on Monday 27th July 21:11
Edited by 911hillclimber on Monday 27th July 21:22
we have a prosportspider with a hewland gearbox FT200.
and changed it a bit:
still not perfect though.
[URL=http://img89.imageshack.us/i/064wzo.jpg/]
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To be honest I think it is more a problem inside the gearbox!
bended leaver or something.
Can't get it out of my head: did they make such an efford of building a car like this and the do such a bad job on gearchanging?
and changed it a bit:
still not perfect though.
[URL=http://img89.imageshack.us/i/064wzo.jpg/]
[/URL][URL=http://img219.imageshack.us/i/063meb.jpg/]
[/URL][URL=http://img220.imageshack.us/i/afrontalshot.jpg/]
[/URL]To be honest I think it is more a problem inside the gearbox!
bended leaver or something.
Can't get it out of my head: did they make such an efford of building a car like this and the do such a bad job on gearchanging?
Edited by donkeasy on Monday 27th July 21:42
Have you thought of changing to a G50. Also what gear oil do you use? Swepco 201 is also the best gear oil for the 915 according to a lot of porker owners - see below from Rennsport
-915-
All Porsche transmissions use a very steep hypoid angle in the differential due to the necessity of close shaft spacing. This is a very highly stressed item and requires the use of a GL-5 Specification gear Lube. Since these gearboxes all use the Porsche-design balk ring syncromesh, they depend upon some friction for these brake-band type syncro's to work properly. The best gear lube for a 901-915-930 transmission is the superb Swepco 201 gear oil. Using a synthetic gear oil in these transmissions will result in higher syncro wear and stiffer shift quality.
-915-
All Porsche transmissions use a very steep hypoid angle in the differential due to the necessity of close shaft spacing. This is a very highly stressed item and requires the use of a GL-5 Specification gear Lube. Since these gearboxes all use the Porsche-design balk ring syncromesh, they depend upon some friction for these brake-band type syncro's to work properly. The best gear lube for a 901-915-930 transmission is the superb Swepco 201 gear oil. Using a synthetic gear oil in these transmissions will result in higher syncro wear and stiffer shift quality.
Gear shifts on these mid engined cars is always a pain I'm told.
I have a 911 road car/hotrod for hillclimbs and road driving.
915 box with a 3.2 engine etc.
I have just put the expensive Swepco 201 (211?) oil in it and can't really tell the difference to be honest.
The G50 box has to be inverted to fit mid engine, the 915 can be fitted with a reverse side CWP like mine has been.
It could be a bad box condition esp as third gets a right pasting on the road cars too.
I have a spare 'normal' 915 super rare in mag alloy and all rebuilt.
Just needs the CWP reversing and ready to go and lighter too, but weaker than the late 915 in the Lola now.
I have a 911 road car/hotrod for hillclimbs and road driving.
915 box with a 3.2 engine etc.
I have just put the expensive Swepco 201 (211?) oil in it and can't really tell the difference to be honest.
The G50 box has to be inverted to fit mid engine, the 915 can be fitted with a reverse side CWP like mine has been.
It could be a bad box condition esp as third gets a right pasting on the road cars too.
I have a spare 'normal' 915 super rare in mag alloy and all rebuilt.
Just needs the CWP reversing and ready to go and lighter too, but weaker than the late 915 in the Lola now.
Edited by 911hillclimber on Monday 27th July 22:31
911hillclimber said:
The second rod stops at the rear chassis just by the drive shafts, and then to the box but at nearly 40 degs! Thus a good shove fore/aft gives a high side component force equal-ish to the fore aft force and things can bind a bit.
The rose joint should be before the UJ.
If it were before then the motion would be linear through the rose joint. As it is at present you are putting in a lot of side load increasing the friction in the rose mount.
Steve
Yep - that looks like the offending area, however before looking at the rose joint it looks to me like the rear universal is not aligned with the centreline of the shaft.
I am assuming the universal is under the red boot. If so, why is there a kink between the red boot and the rose joint?
If this kink is at the junction between the universal (under the red boot) and the rear shaft, then you need to re-fix the universal to the shaft in such a way that it is aligned with the centreline of the shaft.
Check that all universal knuckles are aligned with each other along the shaft.
Also check that all universals are fixed tightly to the shaft, and have no slop in them.
I am assuming the universal is under the red boot. If so, why is there a kink between the red boot and the rose joint?
If this kink is at the junction between the universal (under the red boot) and the rear shaft, then you need to re-fix the universal to the shaft in such a way that it is aligned with the centreline of the shaft.
Check that all universal knuckles are aligned with each other along the shaft.
Also check that all universals are fixed tightly to the shaft, and have no slop in them.
That picture was long ago during the rough-out build.
The joints are all as you say they should be, on the shafts and very tignt. One I had to weld on !
The rose joint on the left is one of a pair attached to the gearbox. These carry a shaft and give a parallel action to the shifter.
I have removed all this linkage you see in the pic and have come off the UJ by the chassis you can see and along to the the very end of the box to the input shaft (as in the Ultima)
The extra length and the very aft position has taken the angle down to about 15 deg in plan view to the C/L of the box. It was 40 deg.
I hope the parts will start to arrive today /tomorrow so I can do the linkage.
The input shaft of the 915 is notoriously weak and can bend all to easily, so a big rose joint will be used to support it, something the Ultima system does not do.
Thank you for the contributions!
The joints are all as you say they should be, on the shafts and very tignt. One I had to weld on !
The rose joint on the left is one of a pair attached to the gearbox. These carry a shaft and give a parallel action to the shifter.
I have removed all this linkage you see in the pic and have come off the UJ by the chassis you can see and along to the the very end of the box to the input shaft (as in the Ultima)
The extra length and the very aft position has taken the angle down to about 15 deg in plan view to the C/L of the box. It was 40 deg.
I hope the parts will start to arrive today /tomorrow so I can do the linkage.
The input shaft of the 915 is notoriously weak and can bend all to easily, so a big rose joint will be used to support it, something the Ultima system does not do.
Thank you for the contributions!
I used a 930 box (box between the 915 and G50) and be aware that the way the shift works changed between the boxs, basically if you copy the Ultima mechanism at the front (assuming the 915 is like the 930) the H patern will be back to front.
Im sure you know this but pointing it out just in case.
Im sure you know this but pointing it out just in case.
Yep, aware and noted.
The Lola reverses the direction so the gear shift pattern on the lever is normal.
The Hewland boxes of old (Mk 6/7/8/9 and the FT 200 used the VW gearcase and some bits but turned 'upsidedown' and as the 915 was designed for the same original application (rear engine, midships box) it all works out.
You have the same luck with the G50.(and the 930 box)
The Lola reverses the direction so the gear shift pattern on the lever is normal.
The Hewland boxes of old (Mk 6/7/8/9 and the FT 200 used the VW gearcase and some bits but turned 'upsidedown' and as the 915 was designed for the same original application (rear engine, midships box) it all works out.
You have the same luck with the G50.(and the 930 box)
That is very correct. The 915 is a dog in comparison, but at least in the road car they do work, just slowly (I have one in my 911 road car).
Even if I change gear slowly the last race had almost no 3rd, it simply refused to go in but sometime it did!
On the very very short lever (the Ultima lever is about 3 x longer than the lolas) the difference between in gear and on the edge of the synchro is about 10mm at the knob.
Maybe a much longer lever would help?
Hadn't thought of that at all...
Even if I change gear slowly the last race had almost no 3rd, it simply refused to go in but sometime it did!
On the very very short lever (the Ultima lever is about 3 x longer than the lolas) the difference between in gear and on the edge of the synchro is about 10mm at the knob.
Maybe a much longer lever would help?
Hadn't thought of that at all...
I hope you are wrong, but I suspect you are right!
Your linkage is almost the same as mine!
I'm doing the easy external stuff as no matter what else, it will be good in the end to have.
Bits arrived today, just waiting on a length of CDMS to arrive.
There is a device from Wevo in USA that places a robust looking gate inside the box to guide the selector rod and forks. This system is also used (but a Porsche design) in the G50 and gives a better shift path.
Expensive at £700 but easy to fit esp when the box is apart.
Maybe just rebuild 3rd and tidy-up synchro's in the current box and add a Wevo.
I hillclimb again in 2 weeks time so will do these linkage mods and see where I am after. This will be the second time I've raced this car ever, so I hope I'm somewhere up the learning curve.
Your linkage is almost the same as mine!
I'm doing the easy external stuff as no matter what else, it will be good in the end to have.
Bits arrived today, just waiting on a length of CDMS to arrive.
There is a device from Wevo in USA that places a robust looking gate inside the box to guide the selector rod and forks. This system is also used (but a Porsche design) in the G50 and gives a better shift path.
Expensive at £700 but easy to fit esp when the box is apart.
Maybe just rebuild 3rd and tidy-up synchro's in the current box and add a Wevo.
I hillclimb again in 2 weeks time so will do these linkage mods and see where I am after. This will be the second time I've raced this car ever, so I hope I'm somewhere up the learning curve.
Edited by 911hillclimber on Tuesday 28th July 21:36
anybody done a seq box in an ultima...? or a conversion kit http://www.sqsracing.com/produkt/277:363:sqs-seque...
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