Drenth Gearboxes
#16
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I have the WEVO everything.... The WEVO solves all problems only if the linkage alignment/adjustment is EXACTLY correct. When it's right, it's butter. When it's the least bit wrong, it's ****.
The WEVO stuff also has to be houred-out like the engine or any other wear part. The little bushings, springs, reverse lock-out, etc, parts all wear out. It's not that expensive to replace a lot of these little parts and, based on my experience, these parts are good for around 80 hours. I've gone through a couple of rounds of these pieces and strongly encourage you to put them on the clock.
#17
Rennlist Member
[QUOTE=PedroNole;5679683]I knew it was too good to be true
I have the WEVO everything.... The WEVO solves all problems only if the linkage alignment/adjustment is EXACTLY correct. When it's right, it's butter. When it's the least bit wrong, it's ****.
When you say you have WEVO everything.. Do you have a synchro-less "dog-ring" gearbox, or are you still using Porsche balk-ring synchronizers.
I understand what you are saying about getting the adjustment right, but once you have the linkage set correctly you should not have any problems for a very long time. If you have to constantly mess with coupler adjustment ect. something is wrong.
Do you run a trans cooler? With higher horsepower using a cooler is very important for 915 longevity.
Here is a pic of the Guard Transmission "pro-shift" synchros or "dog-rings"
I have the WEVO everything.... The WEVO solves all problems only if the linkage alignment/adjustment is EXACTLY correct. When it's right, it's butter. When it's the least bit wrong, it's ****.
When you say you have WEVO everything.. Do you have a synchro-less "dog-ring" gearbox, or are you still using Porsche balk-ring synchronizers.
I understand what you are saying about getting the adjustment right, but once you have the linkage set correctly you should not have any problems for a very long time. If you have to constantly mess with coupler adjustment ect. something is wrong.
Do you run a trans cooler? With higher horsepower using a cooler is very important for 915 longevity.
Here is a pic of the Guard Transmission "pro-shift" synchros or "dog-rings"
Last edited by flatsics; 12-17-2012 at 04:47 PM.
#19
Rennlist Member
Unfortunately this would not be legal for PCA "stock" class rules.
I thought I heard that Dan J. had figured out a mod. that would help 3rd gear synchro last longer. On my trans it is always 3rd gear synchro that wears out. Most of this season I have been nursing it, as it will grind upshifting into 3rd if I try to hurry it. Do you know Dan J. does his trans rebuilds in house, or do he still send them out?
#20
Rennlist Member
Gary,
Unfortunately this would not be legal for PCA "stock" class rules.
I thought I heard that Dan J. had figured out a mod. that would help 3rd gear synchro last longer. On my trans it is always 3rd gear synchro that wears out. Most of this season I have been nursing it, as it will grind upshifting into 3rd if I try to hurry it. Do you know Dan J. does his trans rebuilds in house, or do he still send them out?
Unfortunately this would not be legal for PCA "stock" class rules.
I thought I heard that Dan J. had figured out a mod. that would help 3rd gear synchro last longer. On my trans it is always 3rd gear synchro that wears out. Most of this season I have been nursing it, as it will grind upshifting into 3rd if I try to hurry it. Do you know Dan J. does his trans rebuilds in house, or do he still send them out?
#21
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Gary
Thanks , I really appreciate it.
#22
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I figured a sequential for a 915 would be too good to be true, at the club racer level anyway. Didn't Buckler basically stuff a Hewland inside a 915 (or 930 or G50) case about 10 years ago? Maybe that wasn't sequential, though.
Wanna talk oddities? The first shop I worked for in the early '80's campaigned, of all things, a Fiat 850 in HP. Owner tried to have Doug Peterson (yes, Comptech before they became IMSA/CART/IRL guys) make Hewland FF gutswork inside the stock tranny case.
Back to the sequential, once you use one you don't ever want to go back..........
Wanna talk oddities? The first shop I worked for in the early '80's campaigned, of all things, a Fiat 850 in HP. Owner tried to have Doug Peterson (yes, Comptech before they became IMSA/CART/IRL guys) make Hewland FF gutswork inside the stock tranny case.
Back to the sequential, once you use one you don't ever want to go back..........
#23
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Doug-
No, I use the Porsche synchros. I've yet to wear out a gear but hae gone through some synchros and some dog teeth. However, only after about 50 hours. I hour the synchros and the dog teeth out too.
Tell me the difference between my box and your dog-ring box....
No, I use the Porsche synchros. I've yet to wear out a gear but hae gone through some synchros and some dog teeth. However, only after about 50 hours. I hour the synchros and the dog teeth out too.
Tell me the difference between my box and your dog-ring box....
#24
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I worked with WEVO and Guard to convert my 915 to a dog-box style... But only for the 3-4 shift plane. It's not something that they do a ton of and there were some hiccups but it did solve the issue of my blowing dog-rings every 8 hours...
If you are considering this keep in mind that it's not a huge $ savings in the long run as the shock-loads the dog-box puts into a 915 gearbox will cause potential issues down the drive-line (I've blown a factory gear apart and a CV) but it solved the problem I was having.
What was that? Well with a shortened 3rd gear the dog-ring hangs WAAY over the gear. Eventually it starts to flex and walks off the gear a bit, ends up a little cockeyed and creates harder and harder shifting, accelerating wear and increasing heat, visicous circle. Eventually the syncro-bits would clash with the other bits and I'd end up with lots and lots of bits. I have a stack of broken and mangled 3rd gears at least a foot high in my shop.
Some more photos here:
http://moto-delta.com/wordpress/?m=200706
Chris Streit
MotoDelta Motorsports, Chicago
http://www.moto-delta.com
If you are considering this keep in mind that it's not a huge $ savings in the long run as the shock-loads the dog-box puts into a 915 gearbox will cause potential issues down the drive-line (I've blown a factory gear apart and a CV) but it solved the problem I was having.
What was that? Well with a shortened 3rd gear the dog-ring hangs WAAY over the gear. Eventually it starts to flex and walks off the gear a bit, ends up a little cockeyed and creates harder and harder shifting, accelerating wear and increasing heat, visicous circle. Eventually the syncro-bits would clash with the other bits and I'd end up with lots and lots of bits. I have a stack of broken and mangled 3rd gears at least a foot high in my shop.
Some more photos here:
http://moto-delta.com/wordpress/?m=200706
Chris Streit
MotoDelta Motorsports, Chicago
http://www.moto-delta.com
#25
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I would add that much of that earlier issue of the dogs walking off can be managed by peening the dog-ring onto the gear itself. However I was also stripping dog-teeth and hated the balky shifting which is why I eventually went to this setup. It also requires additional detent work, very precise setup and not something I'd recommend for a shade-tree mechanic.
Chris Streit
MotoDelta Motorsports, Chicago
http://www.moto-delta.com
Chris Streit
MotoDelta Motorsports, Chicago
http://www.moto-delta.com
#26
Rennlist Member
I have a stock transmission, as I am in stock class. I was just trying to offer that for people that are not limited by the rules there are some different options out there.
WEVO can convert a 915 to an all dog-ring trans.
---This is an excerpt from an article on "dog rings"
Call The Dogs
When it comes to manual transmissions there are two basic types of gear engagements, synchronized and dog-ring (also called face-tooth). All factory and some race-type transmissions use synchronizers because they allow for smooth, yet quiet gear engagement. "A synchronizer, or blocking ring as it can also be called, is used to slow the speed gear so that the slider can engage the gear when the gears are shifted," stated Long. "As the driver moves the shift lever he manipulates the shift forks and that moves the sliders. The sliders will start to force the syncronizer onto the tapered ramp that is attached to the speed gear. As the syncro rides up the taper it grabs the gear and slows the gear, or synchronizes the speed of the gear, so that the teeth can engage. When it comes to racing, the limiting factor with a synchronized transmission is often rpm, and that's because as rpm is increased it becomes more and more difficult for the synchronizer to slow the gear quick enough and allow the teeth to mesh. "Normally the limit is around 6,500-7,000 rpm, but a good clutch setup and a good driver may be able to go a little higher," added Long.
When the synchro can't slow the gear down fast enough to engage the gear, the result is grinding and that shreds the teeth on the synchro. Ultimately, the transmission will grind all the time and may pop out of gear. If these symptoms sound familiar it may be time to call in the dogs. The dog-ring gears, that is. A dog-ring (or face-tooth gear as it is called), is a system of gear engagement that essentially has no blocking ring, just big steel lugs (on the slider and on the speed gear) that engage and lock together to drive the transmission. "The lugs on a dog-ring setup are on the face of the gears as opposed to being on the inside diameter of the slider and the outside diameter of the speed gear. So the face of the gear and the slider engage, rather than the inside diameter and the outside diameter of the speed gear. And rather than having 35-40 little teeth that must mesh together, the lugs simply slam together and lock in. There are between three and eight lugs on most face-tooth gears and that allows them to interlock quite easily, with virtually no chance of grinding. The advantage to the face-tooth setup is unlimited shift rpm, quicker shifts and much fewer missed gears; however, you can expect additional noise from the transmission.
#27
Rennlist Member
I figured a sequential for a 915 would be too good to be true, at the club racer level anyway. Didn't Buckler basically stuff a Hewland inside a 915 (or 930 or G50) case about 10 years ago? Maybe that wasn't sequential, though.
Wanna talk oddities? The first shop I worked for in the early '80's campaigned, of all things, a Fiat 850 in HP. Owner tried to have Doug Peterson (yes, Comptech before they became IMSA/CART/IRL guys) make Hewland FF gutswork inside the stock tranny case.
Back to the sequential, once you use one you don't ever want to go back..........
Wanna talk oddities? The first shop I worked for in the early '80's campaigned, of all things, a Fiat 850 in HP. Owner tried to have Doug Peterson (yes, Comptech before they became IMSA/CART/IRL guys) make Hewland FF gutswork inside the stock tranny case.
Back to the sequential, once you use one you don't ever want to go back..........
This car is presently for sale on Pelican parts.
It has a sequential transmision.
1974 Porsche 914-6 2.2 liter Race Car $37,500: Very fast. Very light. Drives, handles and shifts like a shifter cart, only bigger! Everything that can be done to the car, and still be safe, has been done! Current PCA and Vintage / VSCR log books. Professionally built and maintained by Bob Viau and his team at Auto Edge for the last 10 years. PCA GT5R or S class. PCA, NASA, SCCA, POC and Vintage legal. Current PCA inspection, (4/20/07).
Very reliable. Recent rebuild on engine and transmission with test hours only. New suspension. 15 podium finishes in last 20 starts.
Engine: (Andail / Porsche Motorsports Specs. Recent rebuild with test hours only)
• 2.2 liter twin plug six cylinder
• Webber 40 carburetors
• Induction Research flowed 2.4 liter Porsche twin plug heads
• Extensive machining to case and crank
• Pauter Rods, 70 mm stroke
• J&E Pistons custom coated 81mm. 9.8/1 compression
• Custom Web Cams, 104/102 grind
• Titanium retainers with Jerry Woods high tension valve springs
• Tuned length headers with EGT probes, Jet Hot ceramic coated
• Sport tuned stainless steel muffler
• Peterson 16qt front mount oil tank with heater, front cooler and Accusump pre-lube
• All Aeroquip hoses with Earls fittings
• Electromotive crank fire – waste spark ignition
• Turbo valve covers
• New wiring with blade style fuses, all labeled
• Front mounted case breather system with catch can
• Facet electronic fuel pump with micron filters
• 17 gallon fuel cell
Suspension: (New suspension with test hours only)
• Front: Bilstein RSR 220/100 valveing Mono ball mounting
• Koni double adjustable rear.
• Hypercoil springs
• SMR Bump steer kit
• Adjustable front sway bar with mono ball links
• All mono ball or Delrin bushings
Brakes: (This car has way more brakes than it needs!)
• 1986 930 front calipers and rotors on the front and rear,
• Cross drilled rotors
• Stainless steel lines
• Adjustable proportioning valve
Sequential Transmission:
• Porsche case / bell housing containing a Hewland Webster Mark 9 with Mark 5 gears
• PBS sequential shift linkage
• New dog rings
• Ratios: Ring and Pinion: 8/31 1st 12/31 2nd 17/29 3rd 16/23 4th 19/24 5th 24/27
• Quafe limited slip differential
Tub / Chassis: (Very stiff chassis! Absolutely no rust!)
• Porsche tub with 914 GT fiberglass body panels from GT Racing
• All fiberglass body except door skins
• Full custom roll cage welded to the chassis with all suspension points tied in
• NASCAR style intrusion bars on the driver side.
• Factory rear suspension reinforcement plates welded in with additional custom reinforcement
• Reinforced rockers
• Floor pans and rockers replaced last year with NOS parts.
• Paint is a 7 ½ out of 10, Rino-tape on the front end. Some race rash on Rino-Tape in the front. Small dent on the top of the windshield hoop otherwise in great shape!
• Custom gages. Tachometer, Oil Pressure, Oil Temp, EGT gages for each cylinder
• AIM Data Acquisition System
• Custom center panel with EGT switches, Ignition, Accusump activator, Cool Suit air and water regulators, Radio push to talk.
• Rebuilt pedal cluster with bronze bushings, (stock was prone to fail)
• 914 GT Engine cover, (for better cooling)
• Removable GT Racing down force wing, (additional lip spoiler included)
Safety:
• Autoshield aluminum seat bolted to the floor and the roll cage
• Lexan windshield with anti scratch coating.
• Large convex rear view mirror
• Areo convex side mirrors
• SPA fire system with jets on the fuel cell, engine and driver. Activation switches on the outside and inside of the car
• Battery cut off switch
• New Simpson 6 point harnesses
• Cool Suit air and water system, (Cool Shirts not included)
• Wired for radios, (radios not included)
• Removable Sparco steering wheel with quick release
Spares included:
• 3 Front air dams
• 2 Sets of 8 x 15 Fuch wheels
• 8 New Hoosier racing slicks
• 6 Fuel cans
• Custom fuel funnel
• Set of new brake pads
• Several fuel and oil filters
• Some other little parts, (shift cable, clutch cable, bumper, engine cover, engine shroud)
This car cost $125,000 to build. Asking $37,500 or best offer. Contact danmuldowney@comcast.net or (952)356-5308
Last edited by flatsics; 12-17-2012 at 04:47 PM.
#28
Three Wheelin'
I saw a car for sale a couple years ago whose ad mentioned something about a 901 with Hewland/Webster internals. But when I tried to research it further, I came up with nothing. Does anyone know more about this conversion or who does it? (I'll contact the seller of the car listed above, but thought I'd try elsewhere before bothering him).
Not sure this will help the higher hp crowd, though, since neither a 901 nor a Hewland/Webster Mark 9 would be very good at taking much more than 200 ft lbs of torque, if I remember correctly.
Scott
Not sure this will help the higher hp crowd, though, since neither a 901 nor a Hewland/Webster Mark 9 would be very good at taking much more than 200 ft lbs of torque, if I remember correctly.
Scott
#29
Three Wheelin'
I saw a car for sale a couple years ago whose ad mentioned something about a 901 with Hewland/Webster internals. But when I tried to research it further, I came up with nothing. Does anyone know more about this conversion or who does it? (I'll contact the seller of the car listed above, but thought I'd try elsewhere before bothering him).
Pelican ad: http://forums.pelicanparts.com/showt...ewland+webster
Scott
#30
Rennlist Member
Doug -
Unfortunately the part Dan saw the variations in does not seem to solve the inherent weakness of the 915. As for his rebuilding 915's in-house, I think that depends on a few things (like how busy Scott S. is)... but i'm sure he would if specifically requested.
Unfortunately the part Dan saw the variations in does not seem to solve the inherent weakness of the 915. As for his rebuilding 915's in-house, I think that depends on a few things (like how busy Scott S. is)... but i'm sure he would if specifically requested.