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#1 whistler

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Posted 28 November 2019 - 08:58 PM

I'm contemplating a BP255 camshaft from Piper. They offer a new one  or a re-profiled one using your own camshaft for about 60% of the new cost. Is there any difference in quality between the 2 types?



#2 cal844

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Posted 28 November 2019 - 09:47 PM

I'd fit a 266 profile, a 255 is under crammed imo, a reprofiled cam is exactly that, theyll grind your cam to their profile and charge accordingly.

Bear in mind a new cam comes with new followers

#3 Cooperman

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Posted 29 November 2019 - 12:53 AM

You would be better going for a Mini Spares Evo001.



#4 whistler

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Posted 29 November 2019 - 09:46 AM

It's going into a 1098 +0.100" with a modified 295 head, so looking for low torque. Already have an evo001 in the wife's 1330 so I know it's good but I was recommended the Piper as a better cam for the proposed engine. Was sticking with 1.3 rockers.



#5 luismx123

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Posted 29 November 2019 - 07:47 PM

contact AC Dodd. his cams are apparantly top notch and he has one similar ones to the bp255 i think



#6 OzOAP

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Posted 29 November 2019 - 10:33 PM

I'd fit a 266 profile, a 255 is under crammed imo,

A 255 is 264° duration.
They are in the same range as 266, EVO1, MG Metro, SW5 but perform better imho.
I fit billet, oil fed ones to every road engine I build from 850 to 1460. Fantastic profile.
Do not 'over compress' the engine.

Edited by OzOAP, 29 November 2019 - 10:35 PM.


#7 whistler

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Posted 30 November 2019 - 10:33 AM

 

I'd fit a 266 profile, a 255 is under crammed imo,

A 255 is 264° duration.
They are in the same range as 266, EVO1, MG Metro, SW5 but perform better imho.
I fit billet, oil fed ones to every road engine I build from 850 to 1460. Fantastic profile.
Do not 'over compress' the engine.

 

It will have +.100" flat tops and I would be looking for around the 10:1 CR. Would that be about right for a road car?


Edited by whistler, 30 November 2019 - 10:35 AM.


#8 OzOAP

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Posted 30 November 2019 - 11:19 AM

Also, do not over spring the head with these cams.
OAP Conical valve springs are specifically designed for this range.

Edited by OzOAP, 30 November 2019 - 11:23 AM.


#9 OzOAP

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Posted 30 November 2019 - 11:19 AM

It will have +.100" flat tops and I would be looking for around the 10:1 CR. Would that be about right for a road car?

I would aim more towards 9.5/9.75
It can then cope a couple more degrees ignition.

Edited by OzOAP, 30 November 2019 - 11:19 AM.


#10 whistler

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Posted 30 November 2019 - 11:46 AM

Also, do not over spring the head with these cams.
OAP Conical valve springs are specifically designed for this range.

Looking for 180 to 200lb doubles. I think the original 'S' had 200lb.

I'll keep CR under the 10 then. 



#11 OzOAP

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Posted 02 December 2019 - 07:49 AM

A valve spring has two main jobs. To hold valve onto seat and control valve train at full lift, (keeping follower on cam lobe).
To keep valve on seat, 65/75lb is adequate. That is what a normal double spring does, but to do that it means it has 180/200 at full lift (0.330/0.400). That is more than is required and increases parasitic losses and wear.
A conical spring is progressive due to different size coils.
At 70lb seat pressure the OAP springs give 145lb pressure 'over the nose'(full lift), thus there is less wear on followers/cam/chain, more accurate lift and timing due to less pushrod flex, less friction/heat due to not having inner/outer springs rubbing against each other, smaller/lighter top caps, all this makes for a freer revving engine.
They do make a difference and have been banned by the idiots in the Mini 7 Club due to the advantage the springs give.
£100 with std modified topcaps, (exchange). Steel caps available @ £60 extra.

20191202_072759_zps2swmoshh.jpg

#12 ACDodd

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Posted 02 December 2019 - 07:09 PM

What Oz said, and lower compression and more timing is always better that too much compression and retarded Timing. That 255 would be installed with 9.65:1 if I built that.

Ac

Edited by ACDodd, 02 December 2019 - 07:10 PM.


#13 whistler

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Posted 02 December 2019 - 07:17 PM

What Oz said, and lower compression and more timing is always better that too much compression and retarded Timing. That 255 would be installed with 9.65:1 if I built that.

Ac

Thanks for that. Would there be any advantage to using your RS cam in this engine?



#14 ACDodd

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Posted 02 December 2019 - 10:40 PM

The my RS cam is 'a little bit more' cam than the 255.

Send me your email and I shall send you my cam info.

Ac

#15 ACDodd

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Posted 02 December 2019 - 10:40 PM

The my RS cam is 'a little bit more' cam than the 255.

Send me your email and I shall send you my cam info.

Ac




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