Lotus Elan

Dave Bean 114 cams

PostPost by: seniorchristo » Fri May 10, 2019 2:14 am

Dave Bean Engineering offers 114 cams which profess to produce 150 HP with excellent "road manners".
This seems almost too good to be true. I Does anyone have experience with these cams? How would the low end torque compare to sprint camshafts? :)
Thanks,
Chris
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PostPost by: rgh0 » Fri May 10, 2019 2:26 pm

Hi Chris

The Bean 114 came is a good cam and does what it says. The higher lift of .413 makes the head breath a lot better and the relatively short 288 degree seat to seat duration means it has good torque. It will have similar low end torque to a sprint cam if not better. To get the 150hp quoted you need to do a fair bit of porting to help the head breath. In a standard port head with standard valves you may get 140 hp with better mid-range than a standard sprint cam

I have not personally built an engine with this specific cam but have used similar cams as a number of cam makers have similar spec cams e.g. the QED 420 cam.

The best option in my opinion is the McCoy .440 lift 285 degree seat to seat cam. More lift and slightly shorter duration so it does everything the Bean cam does but just a little better. But any cam over .41 lift and under 290 degrees duration is an option

All these cams need new spring packs to suit the higher lift. Bigger valves and bigger ports take their power band higher without loosing to much low end. 170 hp is possible with the McCoy cam in a 1600 street engine if the rest is built and modified right

cheers
Rohan
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PostPost by: seniorchristo » Fri May 10, 2019 4:46 pm

Thanks Rohan
I'm going to go with the 114's from Bean. Not going to do extensive porting because of cost and my lack of experience porting heads. I have a 711 stroker crank I could use for my bottom end rebuild for additional power but 140 HP is a good starting point without have to beef up the drive train with HD axles etc... Thanks for your advice! :)
Chris
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PostPost by: rgh0 » Sat May 11, 2019 12:33 am

seniorchristo wrote:Thanks Rohan
I'm going to go with the 114's from Bean. Not going to do extensive porting because of cost and my lack of experience porting heads. I have a 711 stroker crank I could use for my bottom end rebuild for additional power but 140 HP is a good starting point without have to beef up the drive train with HD axles etc... Thanks for your advice! :)
Chris



It sounds like your planning to build the Bean stage 111-1 as described on page E8 of their catalogue. This is the stage 11 head with standard valve diameter and just cleaned up ports combined with the high lift Stage 111 valve lengths and springs. Back when the catalogue was written you also had to deepen the valve spring pockets to fit in the high lift valve springs. i did that more than 30 years ago on my first high lift twink build and I had to weld up where it broke through into the inlet ports which had also been enlarged :roll: These days with modern valve springs its not needed and you can fit in lifts to 0.50 without machining the spring pockets.

While modifying the valve train for a high lift cam is not difficult it is complex and a number of items can catch you out so if you have not done it before work with suppliers like Bean or some one else to ensure it will all fit together

The hardest bit to get right is that not all combinations of parts supplied for high lift cams will fit correctly in all heads due to the loose original machining tolerances by Lotus plus all the changes that may have happened over the last 50 years to the head during rebuilds. So you need to do some careful checking of things like valve seat location versus cam centre line to ensure the combination of valve stem length, cam base circle, follower thickness and shim thickness all fit and the resultant spring installed height and full lift height have the spring loads in the right range. I typically build for seat loads in the 60 to 80 lb range and full lift loads in the 180 - 200 lb range. High revving race engines towards the top of the range and road engines at the bottom of the range.

cheers
Rohan
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PostPost by: Slowtus » Sat May 11, 2019 1:06 am

Rohan "The best option in my opinion is the McCoy"

I live a little north of Mr McCoy, have corresponded with him off and on and keep careful watch on his doings, both on the track and in his 'shop'.

While he enjoys flinging his Lotus Cortinas/Escorts around various tracks, he has never lost sight of the rigid engineering principles and application required for them to do so.

No competition implied/inferred or wanted twixt Dave Bean and https://omnitech-engineering.com/ - both supply to us Lotus nuts...but while I would happily install a Dave Bean Twin Cam in one of my deserving Lotus, I would probably keep one of John McCoy's offerings for quite a while - uninstalled.

Just to look at...and possibly, accidentally rub against as it sits in my garage...hey - It can't just be me - can it? :D :D :D

Omnitech produces, for me, that mix of form and function...fabulous engineering tied to a great appearance.

(send the usual cheque to the usual place John...or better yet, next time at Mission, you can buy me a hot dog)
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PostPost by: StressCraxx » Sat May 11, 2019 4:03 am

seniorchristo wrote:Thanks Rohan
I'm going to go with the 114's from Bean. Not going to do extensive porting because of cost and my lack of experience porting heads. I have a 711 stroker crank I could use for my bottom end rebuild for additional power but 140 HP is a good starting point without have to beef up the drive train with HD axles etc... Thanks for your advice! :)
Chris


Porting an aluminum head is not that expensive. About 1/3 to 1/2 of cast iron. It's just skilled labor.
As someone who had his head "street ported", that is, ported to clean up the bores of the intake runners and valve inlets and exhaust ports, the difference in performance even with stock cams was impressive. When I added sprint cams and header a few years later the engine really came alive, particularly above 5000 rpm. It was like the turbo had kicked in.
YMMV

Regards,
Dan
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