Crown Wheel & Pinion Suppliers

[uninformed]

Hey all,

 

are there any other suppliers of heavy duty CW&Ps for Rover diffs other than Ashcroft and Great Basin Rovers?

Personally I’m looking for something in the 3.75 to 3.9 ratio region 

 

cheers 🍺

[Stellaghost]

5 minutes ago, uninformed said:

Hey all,

 

are there any other suppliers of heavy duty CW&Ps for Rover diffs other than Ashcroft and Great Basin Rovers?

Personally I’m looking for something in the 3.75 to 3.9 ratio region 

 

cheers 🍺

@Hybrid_From_Hell on this forum, builds diffs, it would be worth giving him a shout as I'm sure one or two members have bought different ratio sets off him

Regards Stephen 

[landroversforever]

There used to be KAM.... but not sure what bits (if any) of theirs are still being produced. @Hybrid_From_Hell may have some in stock.

[uninformed]

2 hours ago, landroversforever said:

There used to be KAM.... but not sure what bits (if any) of theirs are still being produced. @Hybrid_From_Hell may have some in stock.

At some point TerraFirma bought out Kam. I have found 3.8-1 which would suit but there seems little stockists. I’d also like to know where they are manufactured. Spain and Italy have somewhat ok reputation for CW&Ps, China not so much…

 

[Bowie69]

Unless you have a real aversion to Ashcroft I see little reason to go elsewhere for the CW&P, they have HD is just about every ratio you may want.

[uninformed]

The one thing I can comment on going by photos as I have not had all 3 in hand, is the base material thickness below the root of CW teeth is thinnest on the Ashcroft. I guess it’s a combination of tooth size and pressure angle. 
 

Ashcroft use a 8 tooth pinion, GBR and Kam both use a 10 tooth pinion for their 3.9 and 3.8 respectively.

[landroversforever]

I wasn't too worried about that on my ashcroft ones as I've got them both pegged which should support the thinner area.

[uninformed]

I won’t be pegging my cases at this stage. 
 

So who has any recent experience with Kam/Terrafirma CW&Ps? 

[Snagger]

Paging Nigel, paging Nigel… clean up in aisle three…. @Hybrid_From_Hell 

[Hybrid_From_Hell]

Morning All,

There are only a few actual MAKERS of CW&Ps in the world, GBR Terrafirma Britpart Allamkes and many others sell CW&Ps under their own brand or on behalf of.- that incs LR themselves they have them made for themselves !

Additionally there are "Grades" within the manufactuers as well, ie they will make / sell you good CWPs or for less money a cheapened version - so just becuase its a brand "XYZ" can mean nothing !

There are some indian and chinese units out there - aviod like the plague

 

There are when you look at the MAKES CWPS pros and cons for each - whats is the application / Build / whats views have you got on the units you are thinking of any why ?

Nige

[Daan]

I have used the KAM 4.75 since 2002 and they are still going strong. There is a problem with the bolt size of the crown wheel, which is BSP I think, of which there is very little available- there is Hex head bolts of a very low grade, or cap heads, which clash with the bearing cap. I resorted to using the low grade hex head bolts and loctited the crownwheel to the diff flange, which has held out all this time. One thing to check if you go with KAM.

[uninformed]

19 hours ago, Hybrid_From_Hell said:

Morning All,

There are only a few actual MAKERS of CW&Ps in the world, GBR Terrafirma Britpart Allamkes and many others sell CW&Ps under their own brand or on behalf of.- that incs LR themselves they have them made for themselves !

Additionally there are "Grades" within the manufactuers as well, ie they will make / sell you good CWPs or for less money a cheapened version - so just becuase its a brand "XYZ" can mean nothing !

There are some indian and chinese units out there - aviod like the plague

 

There are when you look at the MAKES CWPS pros and cons for each - whats is the application / Build / whats views have you got on the units you are thinking of any why ?

Nige

I’m looking for a ratio 3.75 - 3.9 , Rover diffs front and rear, 110 with M57, ZF 6 speed manual LT230 (30% reduction gears) 

It will probably weigh in around 2300kg

Definitely not a comp rig, touring and some weekend off roading etc.

diffs won’t be pegged.

I wasn’t aware of Britpart doing alternative ratios? And am looking for something stronger than genuine. Ashcroft use to be made in Spain (no idea now) , but no idea where Kam or GBR are made?

[uninformed]

16 hours ago, Daan said:

I have used the KAM 4.75 since 2002 and they are still going strong. There is a problem with the bolt size of the crown wheel, which is BSP I think, of which there is very little available- there is Hex head bolts of a very low grade, or cap heads, which clash with the bearing cap. I resorted to using the low grade hex head bolts and loctited the crownwheel to the diff flange, which has held out all this time. One thing to check if you go with KAM.

That would be a very strange choice for Kam to make and one would question their thinking if that the case…

Rover CW have been 3/8 UNF since at least Series 2 and didn’t change . Not sure about the short nose/P38 type (assume the same)

Ironically LRs supplier of Salisbury took an American diff and made the crown wheel metric thread 😆

[Hybrid_From_Hell]

11 hours ago, uninformed said:

 

diffs won’t be pegged.

 

 

 

Crown wheel bolts from LR Ashcroft and KAM / GBR etc are now all 3/8 UNF, there is a HD  (single use) 12.9 Flange headed bolt with locking serrations available - was used on wolfs P/N FTC5150  and crossed over to civvy use now too - Genuine only - I know who makes them and LR has it as a "Patented' Product - Genuine only 

ANY CWP - whatever the make - having casing pegged makes a massive and I mean MASSIVE increase in strength and reliability,

in fact I would say a Standard 47/13 LR CW&P Pegged is stronger than an unpegged HD CWP of any flavour

The new KAM CWPs are not as good as the Older KAM units, all down to Price vs Quality

KAM CW&Ps are made in Turkey - no great secret sticker is on outside of boxes !

The differences between the 2 main players (Ashcroft & KAM etc) are down to the tooth count / pinion tooth count / land (base plate) and on Ashcrofts (which is our preferred unit for all builds unless customer demands otherwise) they have a different design of the angle -  or more technically the scroll / shape on the  tooth design / teeth - which is a hypoid type of design -this design / style of tooth improves strength by having a greater surface / tooth contact area.

The Ashcroft Land (Base plate) is thinner than KAMs - although gets thicker as you go up ratios - 3.5 thinnest 4.75 thickest ) which has more smaller teeth to allow thicker Land, but pegging an Ashcroft gearset makes for a stronger unit due to the hypoid design and huge teeth and then the Phosphor bronze pad then adds thickness by it being there against the land vs the KAM with a thicker Land and much smaller teeth which by design can sheer easier pegged or not.

KAM Design means it will be quieter than the Ashcroft design maybe - but its in a LR so quiet is not normally a pre requisite - and the Ashcroft require careful setting up especially on Head height - important on any pinion for a good mesh, more so on Ashcroft's maybe - this helps make them quiet when finished

KAM are now technically owed by Britpart as they bought Allmakes who bought KAM and Terrafirma etc, all now under the Britpart Group ownership

 

 

However .......... in simple basic terms ..........

M57 + Anything= Pegged ............Whatever else you buy / think of IMVHO  ................

 

bow lastly 

11” have a short nose differential and there are few CWPs sets about 

 

you can only get 3.54 4.1 and 4.75 KAM do 4.1 and 4.74 Ashcroft do /did can’t remember 4.1 and that’s all you ca have 

 

additionally it’s a dreadful unit …..

 

[Hybrid_From_Hell]

22 hours ago, Daan said:

I have used the KAM 4.75 since 2002 and they are still going strong. There is a problem with the bolt size of the crown wheel, which is BSP I think, of which there is very little available- there is Hex head bolts of a very low grade, or cap heads, which clash with the bearing cap. I resorted to using the low grade hex head bolts and loctited the crownwheel to the diff flange, which has held out all this time. One thing to check if you go with KAM.

Yes Daan, but it also helps that you know how to drive well  + have mechanical sympathy

[Snagger]

12 hours ago, uninformed said:

That would be a very strange choice for Kam to make and one would question their thinking if that the case…

Rover CW have been 3/8 UNF since at least Series 2 and didn’t change . Not sure about the short nose/P38 type (assume the same)

Ironically LRs supplier of Salisbury took an American diff and made the crown wheel metric thread 😆

Any idea if that was just the 110 Salisbury, or the 109 too?  They started the Salisbury on the 109 in 1972, but I think the big push (admittedly not ubiquitous) to metric was 1982 or 84.

[Jon White]

Early KAM 4.75’s had 3/8 BSF threads. I had a set. They recommended that you used the stock series Land Rover swivel bolts as i recall. God knows why they made them BSF - but they did! No idea if the later ones are different.

[uninformed]

13 hours ago, Hybrid_From_Hell said:

 

 

Crown wheel bolts from LR Ashcroft and KAM / GBR etc are now all 3/8 UNF, there is a HD  (single use) 12.9 Flange headed bolt with locking serrations available - was used on wolfs P/N FTC5150  and crossed over to civvy use now too - Genuine only - I know who makes them and LR has it as a "Patented' Product - Genuine only 

 

Any idea of the installation torque LR specifies? I only have WSM up to 98 for Def’r, the D2 WSM I looked at did not have the spec, and by this stage were saying to send the diff back to LR or replace it…

[uninformed]

6 hours ago, Snagger said:

Any idea if that was just the 110 Salisbury, or the 109 too?  They started the Salisbury on the 109 in 1972, but I think the big push (admittedly not ubiquitous) to metric was 1982 or 84.

I have not had my hands in a Series Salisbury, but a quick google revealed the bolt part number of RTC773, and this is stated to be M12….

[uninformed]

2 hours ago, Jon White said:

Early KAM 4.75’s had 3/8 BSF threads. I had a set. They recommended that you used the stock series Land Rover swivel bolts as i recall. God knows why they made them BSF - but they did! No idea if the later ones are different.

The Whitworth thread form is actually VERY good, better in fact than SAE UNC/UNF and Metric, simply because he got it right by using a true radius at thread root and tips. The others use a flat and this creates a larger stress riser. The same reason SAE developed UNR for aerospace etc

Be that as it may, the availability of good bolts is non existent. The fact they suggested using a LR swivel bolt shows that even back then. While LR bolts (Atlas) are generally good quality , the standard for Whitworth bolts ment the highest strength available was between SAE Grade 5 and Grade 8. 
 

As an example, most factory Crown wheel bolts across the brands would be at LEAST Grade 8, and plenty are higher being the equivalent of Class 12.9

Shock loading is high in the application of a crown wheel, much like that of a flywheel to crank. You might notice the original crown wheel bolts LR used had a ‘funny’ head. This was done for a reason, it’s old but very good tech. The head acts like a shock absorber to a degree. Google ‘Place Bolt’ This head type has been and is still used in high shock applications. In vehicles, Ive  seen them factory fitted to crown wheels, fly wheels and drive flanges. 

[Snagger]

4 hours ago, uninformed said:

I have not had my hands in a Series Salisbury, but a quick google revealed the bolt part number of RTC773, and this is stated to be M12….

In that case, I’ll just have to hope the 1/2” bolts for the Dana gears fit the flange bolt holes on the ATB - I don’t really want to open them out 1/2mm just in case I need to refit the 4.71 gears; the extra clearance would not be good for the M12s.  That’s assuming that Stephen can work his magic on the pinion in the first place.  But the original 4.71 gear set will need a spacer ring (last I saw, Ashcroft only make them for the Rover diff, not Salisbury) and longer bolts, so knowing about the grades and problems in this thread is very useful.  So, is 12.8 a bit too brittle for the application, and 8.8 or 10.8 a better choice?

[uninformed]

3 hours ago, Snagger said:

In that case, I’ll just have to hope the 1/2” bolts for the Dana gears fit the flange bolt holes on the ATB - I don’t really want to open them out 1/2mm just in case I need to refit the 4.71 gears; the extra clearance would not be good for the M12s.  That’s assuming that Stephen can work his magic on the pinion in the first place.  But the original 4.71 gear set will need a spacer ring (last I saw, Ashcroft only make them for the Rover diff, not Salisbury) and longer bolts, so knowing about the grades and problems in this thread is very useful.  So, is 12.8 a bit too brittle for the application, and 8.8 or 10.8 a better choice?

The bolt/joint is not designed to be in shear. It is the clamping force and surface friction that is important. Yes plenty of bolts shear but that’s the symptom not the cause…

The shoulder on the hemisphere should be an interference fit with the crown wheel. You’ll find the holes in the hemisphere are not on size for shear (they have clearance). You will probably find they do NOT have enough clearance for 1/2” UNF bolts. Plenty drill them out for Dana gear sets. 
 

If all threads, bolts etc are good , true and installed correctly, AND you spin or loosen, you have gone beyond the design limits. Placing the bolt in shear is not always the answer, even when designed, as can be noted with Toyota Land Cruiser drive flange stud failure…

You won’t buy a 1/2” bolt in 8.8,10.9 etc, that is the Metric Class system of rating. You will buy grade 8, or even Grade 9 (equivalent of Class 12.9). Though the SAE has not officially recognised Grade 9, there are some good brands and some carp…

You could go to the ARP catalogue and see what they have for Dana 60 (try part number 200-3001, they are 1.060” UHL ) If you can get genuine factory Dana bolts, they will be good quality. I see absolutely no problem using bolts in the 180,000 UTS strength range as the vast majority of OEM do and it’s the minimum in Motorsport. Make sure you install the bolts to the torque specification of the bolt, especially if you are changing the strength of the bolt, ie don’t just go by the WSM.

 

Edit: I will add if your genuine LR bolts are marked as 10.9 and you want to stay with that, Grade 8 is the equivalent (Please don’t confuse Class 8.8 for Grade 8, not that you’ll buy a 1/2” bolt in Class 8.8)
 

A note on D60 gear sets, it has been proven that very few to none of the aftermarket brands are as good as genuine Dana. 

Edited March 25 by uninformed
Added information

[Snagger]

That is great information.  Thanks.  The gears are stamped with DANA, so are genuine.

[uninformed]

21 minutes ago, Snagger said:

That is great information.  Thanks.  The gears are stamped with DANA, so are genuine.

Good to hear 👍👍

The advantage of the American stuff is volume and availability… a quick google had bolts coming from everywhere lol. Even though a couple places called them Grade 8, I highly doubt they are given the head markings, which are consistent with Grade 9 ( these have a UTS of 180,000 Psi , same as Class 12.9 ) 

You have plenty of options…

https://shop.broncograveyard.com/mobile/D60-Ring-Gear-Bolt-Set-12/productinfo/11847/
 

https://www.strangeengineering.net/product/dana-60-ring-gear-bolts-with-washers-set.html/
 

screenshot:

[elbekko]

Evidently ARP does some as well: https://arp-bolts.com/kits/arpkit-detail.php?RecordID=5300

I actually went to their site to check if they had any studs available for that application, as I'd expect that to be a better idea since the correct torque is so important? But there might not be enough room for that?