How many horse power MK1 gear box can handle

[rustedandrotten]

Difference is between plastic and elastic deformation. Even undersized bolts that are too long will allow deformation without any measurable plastic deformation occurring in the casing. Think of the extra bolt on a 1275s 12g940 head to stop the head effectively curling due to combustion pressure, similar problem. Will be past you on Sat 7th March Spike.

 

[Alpineandy]

Please note, I'm not much of a mechanic and the workings of gearboxes are a complete mystery to me. [smilie=icon_eek.gif]

The PK6 is used in a few Renaults and I think I remember someone saying the casing flexes and allows a shaft to move out of alignment which causes issues. The boxes from very high mileage ...... Vel satis.... or was it safranes... or avantimes.... or espaces....whatever uses the pk6, apparently show that the seating for a shaft (some shafts?) does go oval.

Hope I've remembered that correctly. Rather a difficult shaped box to strengthen I would have thought.
There was someone on here (either with or looking for a Vee) whose job is to run computer simulations on gearbox specs. It was mentioned that he should look at the PK6 but.... no idea what happened. :s

 

[Adrian]

The housing of the PK6 012 (phase 1) and PK6 017 (phase 2) is not exactly the same.

Just for your consideration :tumble:

I fitted a gearbox housing of a Renault Master which can holds bigger bearings (as i'm told by the gearbox man) with Mk2 internals onto my Vee and its running great so far but did only 2000 miles yet and of course running standard horsepower. :salut: :race:



Some pics of the problem with the PK6 gearbox driveshafts failing when under pressure

Circlip and washer popping out of the box which holds the cup(which contains the three legged roller bearing part/driveshaft) into the gearbox. The design of this part sucks a bit.

Ruined parts


Popping out this cup which then runs over the teeth of your diff



Wrecking the diff


Circlip and washer fitted

 

[shinji]

Is the Renault Master gearbox housing inherently stronger?

 

[shinji]

Yes you can order the filling tool from Renault. Part number 0000167500 £5.21 GBP

Thanks James! This will be added to the parts list that I'm slowly putting together for getting the car ready for MOT (in HK).

 

[Spike]

Is the Renault Master gearbox housing inherently stronger?

A very good question! sounds hopeful. so if we get a stronger casing the obvious problem to sort is the locking ring. How about manufacturing an ally boss that welds on that a steel retainer could be bolted to, this would back up against the lock ring. or have the case welded so it can be machined for two lock rings?
Answers on a postcard please!

 

[Spike]

Adrian, jut looking at your pics and it seems that the circlip holds the drive gear against the planets, is the circlip fitted inside the diff housing (the bit that rotates) or the diff casing (the main g/box)?
I can understand that this is a crap idea either way as any movement here will lead to failure.
I spoke to Scott at SG Motorsport about this and he does agree that this IS the weak point.

 

[Brett]

I very VERY much doubt the van gearbox is any stronger. However, it might be a cheap way to obtain cases. They were an inherent weak spot on the Traffic and vauxhall equivalent. The mate that inspected my box said he had lorry loads of them go through his work shop with all manner of failures.
Something that's also worth baring in mind is that the clutch wants beefing up too. I heard it was a fail safe engineered in by Reno to try and prolong the life of the gearboxes. I know that I occasionally had clutch slip after heavy use and that 1 or 2 people experienced clutch problems whilst out on track last year aswell. This is part of the reason I didn't want to flog a dead horse only to end up with a lame pony. I'd rather start with a half decent horse and turn it into a great racer.

 

[Adrian]

I agree with Brett. I don't think that the casing is allot stronger but in theory bigger bearings can distribute the power better due to more surface. Note is that i'm running standard horsepower and placed this box for more reliability and the amazingly much much better gear ratios of the phase 2 not as the thread is about increasing power/torque and the relation of the box to that.

The circlip does not rotate. It's fitted in the diff housing Spike :approve: There is a upgrade for this problem but I can not find this anywhere on my computer at this moment. Will come up with it but is does not change the fact that all these boxes are made of soft cheese.

The clutch is indeed also a weak point. Slipping when used heavily. :tumble: :tumble:

 

[shinji]

I think the OP does want a box that can handle the power and torque hike. The consensus is what Brett has nicely put, flogging a dead horse, if you want to stick with the original box.

I intend to keep my engine power stock, so I just need a box that has increased reliability like what Adrian has done.

Is the ph2 gear ratios that much preferred over the ph1 ratios?

Which would be cheaper/easier? To build up a Renault Master gearbox with ph2 internals or just find a ph2 box. Ph2 box as a part is quite hard to find on the market I think.

 

[WONGY]

Mine has the ph2 box differences I know are lower ratios 1-3 gear plus though happy to be corrected stronger diff casing

Shift is shorter but that's due to the linkage not the box

Defo difficult to find! I recall a post on here from someone met a gearbox builder suggesting shims etc so someone's thought about it already

 

[Spike]

As for ratios, has anyone listed a table showing the differences between the two boxes?

 

[Brett]

They havent Spike although they definatly keep the engine on the boil more. I found a great log of all the different gear counts of all PK06 boxes a few years back. Unfortunatly I can't find it now but if I do ill forward it on to you. Would be good to see if there's a way of mixing a few different ratios from different boxes to make a very close ratio, track day orientated type ie a much taller 1st, a slightly lower 5th, a MUCH lower 6th and a shorter overal f/d. It's something Renault would certainly not have done from the factory due to it acting more like a 5speed and not cruising at 70mph a 2500rpm. For the budding track day user or someone who is more keen to drive the car on propper roads it might appeal....but then there are a whole load more issues that need sorting before that i suppose.

 

[Adrian]

I had driven a MK2 before but when I fitted this MK2 ratio box on my MK1 it is SO much better. It is a real joy to drive. [smilie=yay.gif] The gears keep the engine just where you want it when accelerating.

I'm not sure about the availability of spare casings en gears and so on Shinji.

 

[Spike]

As you said Brett the box is way too tall for the track but I don't think there would be any benefit closing the ratios up if the overall ratio was lowered.
I cannot think how much fuel would be used on the road with super high ratios.