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Cam question

Posted: Sat Dec 20, 2014 4:51 pm
by J.DURÁN
Hi,

I would like to know your opinions about the best cam for a 998 fast road engine with sport inlet valves, 1,125 exhaust valves and 2 x DHLA

sport cam,R17,BP285,...?

Thanks,
Jorge

Re: Cam question

Posted: Sat Dec 20, 2014 5:03 pm
by The Nun
R17

Re: Cam question

Posted: Sat Dec 20, 2014 5:06 pm
by ibbo
if you can get one r20 best allrounder and kinder to valve gear than r17 as has flatter lobes

Re: Cam question

Posted: Sat Dec 20, 2014 5:55 pm
by Lotus-e-Clan
Just make sure you match the static compression ratio to the cam to get the best out of it...

Image

For a given cam ...

Standard SCR = 10.0:1
Sport SCR = 10.3:1
R17 SCR = 10.7:1
BP285 SCR = 11.0:1
R20 SCR = 11.6:1

Then, if you want good road manners using twin DHLA's on a combined inlet/exhaust in hot weather (your location!) fit 1 cm insulator blocks between the carb and manifold or otherwise the carbs WILL get hot after 20 mins driving on part throttle and it'll run rough (fuel evaporation).

I'm running a GB72 (BP300 equivalent) with an 11.8:1 SCR on twin 40 DHLA's and it' runs like a pussy cat OR a TIGER when provoked. :D

And there is no reason why you shouldn't get perfect running from any of your choices ...but the devil IS in the DETAIL! Many DIY tuners of the past tended to fit go faster bits off someone else's spec sheet and then wondered how they tolerated such a bag of $h1te in traffic. :)
Clan004

Re: Cam question

Posted: Sat Dec 20, 2014 5:57 pm
by bks974c
My recommendation for the R20 too, although it not simply a case of slapping in any cam, the compression ratio needs to be altered to suit each of the cams
to get the best from them.

Scott

Re: Cam question

Posted: Sat Dec 20, 2014 6:57 pm
by J.DURÁN
Thank you for your opinions

I will see what I can get

Re: Cam question

Posted: Wed Jan 14, 2015 9:32 pm
by J.DURÁN
I already have a good second hand R20 cam but i do not have the carrier and multi hole sprocket
has anybody some multi hole sprocket?
I have a sport cam, anybody knows the modification to make a .360" cam?

Thanks,
Jorge

Re: Cam question

Posted: Tue Jan 20, 2015 8:58 pm
by J.DURÁN

Re: Cam question

Posted: Tue Jan 20, 2015 9:25 pm
by bks974c
Don't think its for an Imp

Scott

Re: Cam question

Posted: Wed Jan 21, 2015 9:25 am
by J.DURÁN
Thanks Scott,

Yesterday a friend of my father who has an IMP ( Rally ) provide me this cam. He told me that this cam is for IMP, I see that he is on a mistake