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MNR Vortx Propshaft Damage !!!

cosworthspeed10 - 25/8/10 at 03:32 PM

Hi Guys, I have a MNR with a Busa engine in that keeps snaping propshafts on the universal joints. I have taken the shaft back to Dunning & Fairbank today who said that the propshafts are only rated to 160 Bhp Max (1100 series) and that I need a 1300 series propshaft to cope with the Busa power (180 Bhp), the shaft would then be good for 350 Bhp. The problem is that the Universal joints will be bigger in diameter and I would need a larger diameter bike sprocket adapter to connect to the 1300 series prop.

Is anyone else breaking props like we are and are there any other alternatives?

[Edited on 26/8/10 by cosworthspeed10]

[Edited on 26/8/10 by cosworthspeed10]

Bluemoon - 25/8/10 at 03:35 PM

go CEC?

RazMan - 25/8/10 at 03:37 PM

Have a word with GB Engineering - they custom make driveshafts etc to your spec and they might be able to suggest something.

tomgregory2000 - 25/8/10 at 03:40 PM

i would be worried about them giving you specs in BHP as BHP does not break things torque (the twisting force) does the damage

Mal - 25/8/10 at 04:04 PM

You may have a problem caused by the flanges that the ends of the shaft connect to not being parallel to each other.

cosworthspeed10 - 25/8/10 at 04:04 PM

quote:
Originally posted by tomgregory2000
i would be worried about them giving you specs in BHP as BHP does not break things torque (the twisting force) does the damage

Yes I agree, but i suppose it would be hard to put a torque figure on the shafts as it would be dependant upon traction and engine power. I dare say that when you drop the clutch with a set of slicks on the back at 10,000rpm it will put some serious strain on the propshaft and this is normally when the prop breaks.

coyoteboy - 25/8/10 at 04:16 PM

It still makes more sense to spec shafts for torque as power has sod all to do with it. I see this all the time, with things like performance clutches specified for power figures rather than torque. Walk away and find an engineering company that knows the difference.

Johneturbo - 25/8/10 at 04:31 PM

Hmmm thats what killed my last car

broke at the uv joint engine end, car was a total loss

ETA did you get the propshaft supplied with the kit?

[Edited on 25/8/10 by Johneturbo]

interestedparty - 25/8/10 at 04:32 PM

quote:
Originally posted by coyoteboy
It still makes more sense to spec shafts for torque as power has sod all to do with it. I see this all the time, with things like performance clutches specified for power figures rather than torque. Walk away and find an engineering company that knows the difference.

I expect they are already well aware of the difference, but find it more meaningful to the average customer to give a figure in BHP that might bear some relation to the torque.

cosworthspeed10 - 25/8/10 at 04:42 PM

quote:
Originally posted by Johneturbo
Hmmm thats what killed my last car

broke at the uv joint engine end, car was a total loss

ETA did you get the propshaft supplied with the kit?

[Edited on 25/8/10 by Johneturbo]

Yes the prop was supplied with the kit. I suppose MNR should not supply this prop if the manufacturer says it's not suitable?

DRC INDY 7 - 25/8/10 at 04:42 PM

Have a word with danny keenan at mk sportscars he runs a holeshot tuned busa engine in his race car no probs with the propshaft

Johneturbo - 25/8/10 at 04:44 PM

Thing is though a bike engine like say my R1 on the bike is around 170/180bhp but only 90ftlb of torque

i think the zzr1400 is 198hp but only 117ftlbs

busa would be about the same?

Johneturbo - 25/8/10 at 04:48 PM

quote:
Originally posted by cosworthspeed10

quote:
Originally posted by Johneturbo
Hmmm thats what killed my last car

broke at the uv joint engine end, car was a total loss

ETA did you get the propshaft supplied with the kit?

[Edited on 25/8/10 by Johneturbo]

Yes the prop was supplied with the kit. I suppose MNR should not supply this prop if the manufacturer says it's not suitable?

What have mnr said about the max power of said supplied propshaft?

i thought i was just unlucky when mine broke but maybe they arn't a good make after all.

i think Andy from ABperformance uses Bailey Morris

paublo999 - 25/8/10 at 06:21 PM

Due to my combination of sticky tyres, 100lbs ft torque and a nasty vibration I went to a top spec Bailley Morris prop. Not a place to skimp on guys as this thing could kill you.

The dunning prop IMO was not up to the job I needed it to do. I decided not to sell it on eBay for that reason.

cosworthspeed10 - 25/8/10 at 06:34 PM

I have not spoken to MNR yet but I will contact them tomorrow. If the prop manufacturer says its not up to the job then they should not be sold with the kits. As has already been mentioned when a prop blows it can cause massive damage, on my car it has torn a hole in the floor and ruptured one of the 10mm fuel lines. It could have been very nasty!

The universal joints on the prop are GKN which are supposed to be good joints. D&F don't make the joints they simply assemble and cut the prop to length.

[Edited on 25/8/10 by cosworthspeed10]

cosworthspeed10 - 25/8/10 at 06:59 PM

quote:
Originally posted by Johneturbo
Thing is though a bike engine like say my R1 on the bike is around 170/180bhp but only 90ftlb of torque

i think the zzr1400 is 198hp but only 117ftlbs

busa would be about the same?

The power figures listed above is what the engine can develop, the torque developed when you drop the clutch from 10,000rpm with sticky tyres will be much more with all the inertia from the engine when the clutch engages.

Did your prop fail in motion or when doing a fast start?

procomp - 25/8/10 at 07:07 PM

Hi

So how then do the CEC's manage to use the small joints and run 180FtLb.

Use a decent prophaft supplier who uses new parts throughout the build of the shaft.

Cheers Matt

daviep - 25/8/10 at 07:17 PM

quote:
Originally posted by tomgregory2000
i would be worried about them giving you specs in BHP as BHP does not break things torque (the twisting force) does the damage

I wouldn't be worried at all, torque at the propshaft is completley different to the torque produced at the flywheel due to the mechanical advantage of the gearbox and also the primary reduction on a bike.

Horsepower and propshaft speeds are what you need to calculate torque on the propshaft.

So if you know the speed range the propshaft will operate in (most automotive applications will be similar dependant on wheel size and diff ratio) then all you need to know is the engine BHP to calculate whether the prop is strong enough.

Davie

cosworthspeed10 - 25/8/10 at 07:22 PM

quote:
Originally posted by procomp
Hi

So how then do the CEC's manage to use the small joints and run 180FtLb.

Use a decent prophaft supplier who uses new parts throughout the build of the shaft.

Cheers Matt

Matt do you know for definate that the CEC's run the 1100 series joints? I don't think they do. The reason they use them on the BEC's are because the bike sprocket adapter is very close to the clutch slave cylinder (on the Busa motor anyway) and there isn't really any room for a bigger joint

Also CEC's may have different ratios on the rear diff. My car has a 3.14 rear diff.

daviep - 25/8/10 at 07:24 PM

quote:
Originally posted by coyoteboy
It still makes more sense to spec shafts for torque as power has sod all to do with it. I see this all the time, with things like performance clutches specified for power figures rather than torque. Walk away and find an engineering company that knows the difference.

Spoken with conviction but still a load of rubbish apart from the bit about clutches which is irrelevant.

Davie

BobM - 25/8/10 at 08:11 PM

Having had my prop fail twice on my Busa powered Fury I discovered the reason was that the nut holding the adapter onto the gearbox output shaft was fouling the prop yoke and preventing it from seating properly on the adapter. We ended up grinding down the nut a little bit and it fits nice and flush now.

What was happening was that the bolts were trying to bend the end flange on the prop which then meant either the UJ failed or the flange snapped.

Worth checking.

Johneturbo - 25/8/10 at 08:18 PM

quote:
Originally posted by cosworthspeed10

quote:
Originally posted by Johneturbo
Thing is though a bike engine like say my R1 on the bike is around 170/180bhp but only 90ftlb of torque

i think the zzr1400 is 198hp but only 117ftlbs

busa would be about the same?

The power figures listed above is what the engine can develop, the torque developed when you drop the clutch from 10,000rpm with sticky tyres will be much more with all the inertia from the engine when the clutch engages.

Did your prop fail in motion or when doing a fast start?

mine failed in motion i was doing 40mph then went into a 60phm zone and floored it in second then bang! it snapped it a fuel line cought fire and was a total loss within about 10mins
lucky me nor the otherhalf were injured.

here's the old thread
http://www.locostbuilders.co.uk/viewthread.php?tid=96533

Description

Description

[Edited on 25/8/10 by Johneturbo]

mangogrooveworkshop - 25/8/10 at 11:00 PM

ALL THE BETTER REASON TO PUT SOME PROP CATCHERS ON when we look at the above posting by Johneturbo

Johneturbo - 26/8/10 at 12:49 PM

i did a search on props and found a thread
that had some info on UJ's

taken from the thread.........

Dave Mac propshafts in Coventry

I just ordered a new propshaft from them today to do a gearbox change.

They charged �95 plus vat and do a 24hr turn round. It will be all new, painted and balanced, 1140 series UJ's* (rated for continuous 400Nm or 50% possible overload to 600Nm), ford rocket spline to english axle flange.

*Bigger UJ's would be more expensive; 1300 series are rated for 556Nm continuous and 1000Nm max possible, but are bulkier and might not fit the tunnel"

i know you said about the 1100 and the 1300

cosworthspeed10 - 26/8/10 at 07:55 PM

quote:
Originally posted by Mal
You may have a problem caused by the flanges that the ends of the shaft connect to not being parallel to each other.

Looks like you may have hit the nail on the head there!

When I spoke with Dunning & Fairbank today they asked if the prop flanges were parallel to each other. The flanges ideally need to be parallel (Horizontally and Vertically) for the Universal Joints to work well together, in the Horizontal plane because the engine is rotated 10 degrees in the chassis the prop flanges are not parallel to each other but they are in the vertical plane. I think you can have flanges that are not parallel to each other but this need to be specified when selecting the prop as the Universal Joints need to be angled differently from one end of the prop to the other to allow for this. My prop is designed for parallel flanges (as may all the MNR BEC props) and MNR may not have taken into consideration the unparallel flanges.

Does this make sense?

Johneturbo - 26/8/10 at 10:53 PM

Mine is parallel on the horizontal plane but not in a vertical plane
i take it the busa has to be mounted like that to compensate for fitment?

so how would they modify the propshaft for you, is that something DF can do

[Edited on 26/8/10 by Johneturbo]

cosworthspeed10 - 27/8/10 at 05:24 AM

I think they offset the universal joints on the splines, the angle will depend on how much.

40inches - 27/8/10 at 10:41 AM

quote:
Originally posted by cosworthspeed10

quote:
Originally posted by Mal
You may have a problem caused by the flanges that the ends of the shaft connect to not being parallel to each other.

Looks like you may have hit the nail on the head there!

When I spoke with Dunning & Fairbank today they asked if the prop flanges were parallel to each other. The flanges ideally need to be parallel (Horizontally and Vertically) for the Universal Joints to work well together, in the Horizontal plane because the engine is rotated 10 degrees in the chassis the prop flanges are not parallel to each other but they are in the vertical plane. I think you can have flanges that are not parallel to each other but this need to be specified when selecting the prop as the Universal Joints need to be angled differently from one end of the prop to the other to allow for this. My prop is designed for parallel flanges (as may all the MNR BEC props) and MNR may not have taken into consideration the unparallel flanges.

Does this make sense?

I can't grasp this because:
Your second drawing describes many BEC installations (my MK is the same)
Wouldn't the centre bearing compensate for the discrepancy in angle?
If the joint is offset on the splines, how is it calculated? There are 2 more joints on the centre bearing, surely they would also have to be adjusted?
Perhaps I am thicker than I thought, and am talking borrocks

Johneturbo - 27/8/10 at 11:22 AM

This is a good site to understand angles

i find it all rather confussing to be honest!

http://www.vibratesoftware.com/html_help/html/Diagnosis/Propshaft/Propshaft_Angles.htm

cosworthspeed10 - 27/8/10 at 05:19 PM

I think the link Johneturbo posted is very useful but also very Mathematical. They talk about the phase of the UJ's being in line when the flanges are parallel. MK may have taken into consideration the flanges being angled and had their props make with a phase offset on the UJ's, this is not the case for MNR. Don't know how to calculate that but D&F do. The standard props with UJ's in phase will take some misalignment but not as much as 10 degrees. The UJ's are currently fighting each other and this may have caused the failure.

JoelP - 27/8/10 at 07:30 PM

the easiest way to understand the phase issue is to take it to the extreme - if you had a lego U/J which bends to 90 degrees, then you would have to rotate one shaft 180 degrees, then the other, and they could not drive each other. So with a small angle in one uj, assuming the input side is a constant rpm, the output side is going slightly slower for 180 degrees then slightly faster for 180 degs. This vibration would be ruinous eventually. By having the two or 3 u/js lined up, with parallel ends, the vibration cancels out.

If i build a 7 style bec, id have the engine pulled backwards into the passanger footwell and use a shorter one piece prop, and make a much stronger/lighter front frame for the suspension to mount to. It could be done much better if there wasnt the need to leave a huge hole for the engine.

silky16v - 29/8/10 at 08:06 PM

1 thing to point out which i found out on my MK Indy R1 BEC is alot of people overlook greasing the UJ's the needle rollers go dry and then wearout and break thus causing the UJ to fail

7 out of 9 4x4 Cosworths i owned i had to replace the front propshaft UJ's because of this
I remember taking 1 off and it had no needles roller left and i'd been doing some top speeds the nite before

coyoteboy - 25/2/13 at 12:36 PM

quote:

Spoken with conviction but still a load of rubbish apart from the bit about clutches which is irrelevant.

Sorry, but you're wrong. Sure you can work back to torque if you know your BHP and shaft RPM, but it's still a torque rating on the prop. Shafts should not be specified in BHP, they should be specified with a torque limit and an RPM limit (max bearing speed, might be important depending on shaft angle). Anyone specifying them in BHP is ignoring details that matter and are making massive assumptions. I'd rather not work with people who make such assumptions, or buy from them. Sometimes you're forced to, but it doesn't make it right.

Anyone specifying a power limit on a shaft is opening themselves up to failure. If you present the torque limits and RPM limits the customer must identify their shaft speeds and torques and match them to suit. If you spec a power the customer will brainlessly match flywheel output to shaft rating and there's a distinct possibility that'll go pear shaped - you can't possibly claim that the RPM ranges for automotive shafts are similar. Nor can you assume that engine output torque is the only torque-based cause of shaft failure - if I have sticky tyres and a 20Kg flywheel spinning at 10K RPM on the end of a V8 and I sidestep the clutch it'll have much more effect on the shaft than if I do the same with a bike engine, even if the cars weigh the same and are restricted to the same output power, due to the vastly higher inertia of the powertrain.

Since you think I'm wrong, please explain why.

[Edited on 25/2/13 by coyoteboy]

Charlie_Zetec - 25/2/13 at 05:03 PM

This is something I think has been significantly overlooked in the whole topic here! As silky16v says, you need to remember to grease the UJ's to keep them in good working order. All good quality UJ's will have a grease nipple in them, doesn't take 2 seconds to top them up and check from time to time.

I know this from personal experience, not with 7's, but with Land Rovers - where you can all imagine they take a beating on and off road. I think this alone adds to the question of how to choose a suitable prop shaft.... Defenders have not got great power, but plenty of torque!

But in terms of spec'ing up propshafts, I think you can't rely of BHP or torque alone when ordering. It's like ordering a steak - you can have it very rare through to well done. But there's also the choice of t-bone, rump, fillet, etc. Unless you know all the details, you're never going to get the right one. Speak to any professional, and they'll ask these details before supplying anything.

quote:
Originally posted by silky16v
1 thing to point out which i found out on my MK Indy R1 BEC is alot of people overlook greasing the UJ's the needle rollers go dry and then wearout and break thus causing the UJ to fail

7 out of 9 4x4 Cosworths i owned i had to replace the front propshaft UJ's because of this
I remember taking 1 off and it had no needles roller left and i'd been doing some top speeds the nite before

flak monkey - 25/2/13 at 07:21 PM

FWIW when I rebuilt mine with the Duratec Bailey Morris gave me the same advice and recommended I went for the heavy duty prop. It was considerably bigger diameter and much heavier than the standard duty one. Can't remember what it was rated to for power and torque, but it was 'adequate'