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camshaft question


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Hi, I have an N/A 2.2 912 LC ('85 s3) engine with aftermarket high compression pistons (unknown history) I am going to convert to TB fuel injection, will I benefit from a 107 camshaft? will it give more top end or mid range?

thanks, rick

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I have no Idea whats in it al I know (from the invoice history) that somebody paid a lot of many to convert to high compression pistons (steel liners) in the past. what is the best way to check them? any marks on them?

thanks, rick

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look right behind the pulley, if you see 7's going around the diameter, it is a 107. If you see 4's going around the diameter, it is a 104. Those would be the most common cams to find in that engine, pretty sure it was two 107's from the factory.

most kent cams are marked on the end opposite the cam pulley, you would have to pull the cam end covers and unbolt the shim to see the numbers.

Indeed, Garry's thoughts are two 107's in a high compression 2.2 is the waste of a good engine. A 104 & 107 is a good combo, or even two 104's. Most 910 based turbo engines used two 107's.

Personally, I am using a L14 kent (104 spec's) and a 107 in my current engine build. Hard to find any 104 lotus cams floating around anymore, they were only used in the 912hc.

Brian

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Without wishing to hijack this thread, I'm running 2 x L14's (simialr to 104's?).

And I understood that full lift is at 106deg ATDC, and there is 282deg duration -please can anyone shed any light on this?

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  • 2 weeks later...

............ ......... .. Kent Lotus OEM Dave Smith

Cam ID ............ L14 104 107 DS2

Lift .................. .415" .410" .378" .415"

In. Opens, BTDC 35° 32° 22° 36°

In. Closes, ABDC 67° 60° 50° 64°

Ex Opens, BBDC 67° 60° 50° 64°

Ex.Closes, ATDC 35° 32° 22° 36°

Duration ............ 282° 272° 252° 280°

Overlap ............ 70° 64° 44° 72°

MOP, ............... 106 104 104 104

104 Int / 107 Exh combo gives you 54° of overlap, still good for turbo engines

Edited by MrDangerUS

MrDangerUS

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The L14 is said to be within 1% of the 104 specs, the lotus cam duration spec is not measured from closed to closed, but from x amount of distance from the seat. That is the closest cam available to a 104 that I found. The slight difference of the mop is in the right direction once you skim the head if you use a standard head gasket and a green dot 104 pulley I believe.

Doing some porting on the head will help the LC head, bowel porting is pretty easy to do, and will make some measurable gains in hp. Google bowel porting and you will see some examples.

Brian

Edited by bharper
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BTW my cams are marked KCL14, which was only visible after removing the from pulley bolt/washer.

I'm guessing this stands for Kent Cams L14(?).

Other markings (on the cam itself) were the basic Lotus i.e. A907........

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