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Oem Camshafts


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#1 NOT850

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Posted 06 May 2018 - 04:05 PM

I'm looking at doing a rebuild of my 1100 and was looking into other mini engines as a comparison to output figures.   Looking at the 997 cooper engine which has almost the same compression ratio as to my 1100, same head and I will be running the same inlet and exhaust, the figures are around 55hp and 54lb-ft of torque.   My 1100 out of the factory has 48 hp and 60lb-ft.   The extra torque cam be explained by the longer stroke and the camshaft explains the extra hp.   

 

But then I look at the lower spec 1275 engines and they have almost the same horsepower and torque figures as the 997 cooper engine but with larger bore.   But the head is an open chamber with larger valves.   

 

So basically my question is that are the Leyland camshafts originally fitted quite poor performance wise and if replace the 948 camshaft in my 1100 to one such as a minispares Evolution001 camshaft, MD266 or RE266ss will the power figures produce any real difference?

 

Thanks for your advice.



#2 carbon

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Posted 07 May 2018 - 05:41 PM

The MG1100 used a 295 head, twin HS2s, and a 'freeflow' type exhaust. This gave factory quoted 59bhp with compression of under 9:1 using the same cam as you already have fitted in your standard 1100.



#3 Dusky

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Posted 08 May 2018 - 10:19 AM

The modern cams give more torque and a better mileage.
It's a 30 year jump in cam technology really.



#4 carbon

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Posted 08 May 2018 - 06:45 PM

Unfortunately the scope to radically improve the A-series cam is seriously limited by the cam follower diameter, and many of the improvements in A-series cam profiles were developed over 30 years ago...



#5 Dusky

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Posted 10 May 2018 - 06:54 PM

Unfortunately the scope to radically improve the A-series cam is seriously limited by the cam follower diameter, and many of the improvements in A-series cam profiles were developed over 30 years ago...

Time for someone to make roller cams for A series. ;)



#6 hhhh

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Posted 10 May 2018 - 07:17 PM

Unfortunately the scope to radically improve the A-series cam is seriously limited by the cam follower diameter, and many of the improvements in A-series cam profiles were developed over 30 years ago...

Which 30 year old cam does this with a smooth idle (red curves)?

90f915739d80eb591e2715beb4a2fa5405807e6d



#7 carbon

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Posted 10 May 2018 - 08:07 PM

I had the Vizard developed MD286 in mind, developed in the mid-late 80's, but I don't think this was optimised with smooth idle as top priority.

 

But depending on the capacity of the engine in the SRE dyno plot the 286 might still compare favourably well for mid-high rpm torque?



#8 Chris.Williams

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Posted 10 May 2018 - 08:24 PM

I had a Swiftune SW5-07 in my 1098, went like a rocket, heaps of torque and really nice to drive.
Try and resist the urge to over-cam your engine.

#9 NOT850

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Posted 11 May 2018 - 02:11 PM

Chris what else was done to your 1098?

#10 racingbob

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Posted 11 May 2018 - 02:42 PM


Unfortunately the scope to radically improve the A-series cam is seriously limited by the cam follower diameter, and many of the improvements in A-series cam profiles were developed over 30 years ago...

Which 30 year old cam does this with a smooth idle (red curves)?
90f915739d80eb591e2715beb4a2fa5405807e6d
what cam is it and what cc engine

#11 hhhh

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Posted 11 May 2018 - 06:47 PM

Not sure, but it's a big bore with AC Dodd's RS cam, 1.3 rockers. The other curve is a 544.



#12 racingbob

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Posted 11 May 2018 - 08:03 PM

Not sure, but it's a big bore with AC Dodd's RS cam, 1.3 rockers. The other curve is a 544.

imagine bit more than 1275. also rs or rs plus

#13 Chris.Williams

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Posted 11 May 2018 - 08:51 PM

Chris what else was done to your 1098?

+40 Pistons, twin su's, RC40 exhaust system, electronic dizzy and just a reconditioned head.
In the end though we pocketed the black and fitted a 12G940. Then it went hard!
Still have it under the bench.

#14 hhhh

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Posted 11 May 2018 - 09:11 PM

 

Not sure, but it's a big bore with AC Dodd's RS cam, 1.3 rockers. The other curve is a 544.

imagine bit more than 1275. also rs or rs plus

 

RS and it may be a 1330.


Edited by hhhh, 11 May 2018 - 09:13 PM.


#15 racingbob

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Posted 12 May 2018 - 07:16 AM


 

Not sure, but it's a big bore with AC Dodd's RS cam, 1.3 rockers. The other curve is a 544.

imagine bit more than 1275. also rs or rs plus
 
RS and it may be a 1330.
is it slarks when at amsebury or new dyno at Bristol

Edited by racingbob, 12 May 2018 - 08:38 AM.





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