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Piper 310 Cam


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#16 Cooperman

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Posted 21 November 2020 - 05:20 PM

That final drive wont suit the cam /sccr box combination. I'd say 3.9:1 is the absolute tallest fd you want, probably 4.2:1


That is quite right. A 4.3 final drive is about the lowest that will work, unless a lot of clutch slipping is acceptable every time you start from rest (= frequent clutch replacement).

#17 VLChurchill

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Posted 23 November 2020 - 04:59 PM

 

That final drive wont suit the cam /sccr box combination. I'd say 3.9:1 is the absolute tallest fd you want, probably 4.2:1


That is quite right. A 4.3 final drive is about the lowest that will work, unless a lot of clutch slipping is acceptable every time you start from rest (= frequent clutch replacement).

 

 

clutch slip will be the least of his issues, firstly keeping wheel spin at an acceptable level in order to accelerate and then there's the issue on every upshift, where it will drop off the cam and bog down.  Even a 296 in a 1380 with a 3.44:1 was on its limit of acceptability.  


Edited by VLChurchill, 24 November 2020 - 12:52 PM.


#18 Cooperman

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Posted 25 November 2020 - 10:48 PM

No-one with any experience of really 'hot' cams would dream of using anything much hotter than a 276 in a road-going 1275. Torque is what is needed for a road car and one of the best cams is the MG Metro/Kent 266 (virtually identical).

A 310 might be fine for pulling 7800 rpm in top down the straight at Silverstone, but on the High Street it would be virtually useless and cause a lot of by-standers to laugh at an old car with all revs and no go.



#19 VLChurchill

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Posted 05 December 2020 - 01:50 PM

No-one with any experience of really 'hot' cams would dream of using anything much hotter than a 276 in a road-going 1275. Torque is what is needed for a road car and one of the best cams is the MG Metro/Kent 266 (virtually identical).

A 310 might be fine for pulling 7800 rpm in top down the straight at Silverstone, but on the High Street it would be virtually useless and cause a lot of by-standers to laugh at an old car with all revs and no go.

 

Is that your opinion ?  



#20 nicklouse

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Posted 05 December 2020 - 02:40 PM

 

No-one with any experience of really 'hot' cams would dream of using anything much hotter than a 276 in a road-going 1275. Torque is what is needed for a road car and one of the best cams is the MG Metro/Kent 266 (virtually identical).

A 310 might be fine for pulling 7800 rpm in top down the straight at Silverstone, but on the High Street it would be virtually useless and cause a lot of by-standers to laugh at an old car with all revs and no go.

 

Is that your opinion ?  

 

Let’s put it like this.

would I like driving my 1293-296 hill climb engine on the road? Not a hope in hell. Did I enjoy driving my 1380-286 on the road? Yes

 

the 1380 made way less power and just about produced power where you would not be killing clutches by slipping them in trafic.



#21 Cooperman

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Posted 05 December 2020 - 08:38 PM

 

No-one with any experience of really 'hot' cams would dream of using anything much hotter than a 276 in a road-going 1275. Torque is what is needed for a road car and one of the best cams is the MG Metro/Kent 266 (virtually identical).

A 310 might be fine for pulling 7800 rpm in top down the straight at Silverstone, but on the High Street it would be virtually useless and cause a lot of by-standers to laugh at an old car with all revs and no go.

 

Is that your opinion ?  

 

I would rather say that it is experience from almost 60 years of working on Minis of all types.

My 1964 'S' will drive on the roads with a 286 and a SC CR gearbox together with a 3.9:1 FDR, but it is rather 'cammy' and on tarmac rally special stages/tests where I can keep the revs between about 5000 and 6600 rpm it is especially good. However, on a normal road drive, my 1990 Cooper with an MG Metro cam is just as quick and much smoother. But then I am not then looking for the fastest possible time over a given distance on narrow tarmac roads, although that is not to say that I drive it particularly gently.

Engine wear rate is also much lower with the MG Metro cam as it doesn't have to rev high all the time.



#22 Tones61

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Posted 06 December 2020 - 05:36 PM

My spec:
1380,slark head,12:1 comp,Newman 300 deg cam,omegas,
45 Weber,lcb,maniflow,
1.5 rollers,light flywheel,grey clutch,3.4 diff,
10 inch mb wheels,
110 bhp
Just about driveable on road,best for a weekend run out/blast :-)

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