Lotus Elan and Lotus Elan Plus 2 Forums

hi all,
did someone try the LOTBP285 ultimate road cams with 40 weber carbs?

i'm using the weber 40 dcoe 18 carbs, with the weber sprint setup (jet,idle, ..) taken from the workshop manual ( weber 40 dcoe 31), but i think the engine could have some more power. do I have to use a better weber setup or maybe a different type of carbs to get a better performance? dellortos? 45 webers?
some experiences?

thanks in advance
kai

piper cams specs taken from the web page ...

LOTBP285
Ultimate Road
Cam Code LOTBP285
Application Ultimate Road
Power Band 2000-7000
Power Increase 16BHP
Duration Inl 280?
Duration Exh 280?
Valve Lift Inl .384"
9.75mm
Valve Lift Exh .382"
9.70mm
Timing Inl 30 - 70
Timing Exh 70 - 30
Full Lift Inl 110?
Full Lift Exh 110?
Lift AT TDC Inl .090"
2.28mm
Lift AT TDC Exh .088"
2.23mm
Valve Clearance Inl .008"
.20mm
Valve Clearance Exh .010"
.25mm

hi,
i found one big mistake in my weber setup, the choke size was 30 instead of 33 .. well, seems to work better now .

The Piper cam is not that much different than the standard sprint cam with a little more lift ( .392 lobe versus .360) and a little more duration( .280 versus 272 degrees). The sprint 40DCOE jettings should work OK as you have found but a trip to a rolling road dyno is probably worthwhile to fine tune it further.

The quoted power increase look like its versus the SE cam engine of 115 hp with a 12 hp increase quoted for the BP270 cam which looks identical to a 126hp sprint cam specification and a 16 hp increase quoted for the BP285 cam giving it 130 hp which is about right for just the cam swap in an otherwise standard engine

The .392 cam lobe takes you over the lift that the standard valve train components can normally handle. I hope you have replaced the springs at least with something that can accommodate that lift without binding. The Piper data does not show it requires changing of valve train components but it should

cheers
Rohan

Hi Rohan,

you are totally right, I was looking for a not so expensive solution to get some more power (something near the sprint specs) when moving from a Stromberg head to a Weber, so the idea was just to change the cams and modify the head. The head was modified for unleaded fuel, spring inlet valves and the valve springs were replaced (as i remember i took something similar offered for Kent cams). Its working fine for me and the power output is ok, it seems that I have to invest in a rolling road dyno to get a better result .. many thanks

May I revive this post please and ask you elan_s4 how the piper cams have been in your car these past few years?

The reason I ask is that I planned, on Rohan/s suggestion to fit QED420 cams to a fast road engine that I will build shortly. I wish to do the job properly and listened carefully to the reasoning behind the 'long bolt modification' that makes a lot os sense to employ at the start for maybe not a huge outlay. However, finding someone to make the mod has not been easy.

Enter Piper cams. I had a good chat with someone there who knows all abot the mod and can be easily done. Result! Then the conversation drifted into type of camshaft - fast road or ultimate road. Ultimate Road seems the winner, it has a 030" (nearly 10%) extra lift but comes in at 2000RPM against 1500RPM for Fast Road. So I would be interested how you are with the Ultimates.

Rohan, although you maybe use Rally and/or Race, do you have any comments on the Ultimate (particularly regarding the compatibility with Q55s?) - and indeed Piper over QED (if they are not the same thing...)

The Piper "fast road" cam is essentially the Lotus sprint cam in lift and timing. The "ultimate road" cam has additional duration of about 10 degrees to 280 degrees and lobe lift of about 0.030 to go to 0.390 inches. At 6500 rpm you would get maybe 135 hp depending on the rest of the build details in a 1600cc Twincam. Their rally and race cams are old school with to much duration for their lift

The QED 420 goes a step further to 0.420 lift and duration of 285 degrees which about the maximum duration for a road engine and gets around 145 hp in a 1600 twink at 6500 rpm. The McCoy 0.440 lift cam has 285 degrees duration also and is the highest lift cam I have found at that duration and gets around 155 hp in a 1600 cc twink at 6500 rpm and more if you build a bottom end to take additional revs.

The Twincam loves extra lift so I use the McCoy cam in a road engine but its installation gets more complex to fit in that higher lift. The QED420 is not as good performance wise but its an easier fit with the Q55 springs if you are limiting your max revs to 6500 rpm which are the limit for those springs.

If building a bigger capacity say 1700cc engine going to the higher 0.420 or 0.440 lifts are even more beneficial

Thanks Rohan. The QED420 is certainly a higher lift than the Piper Ultimate but only 5 degrees more dwell, so in effect, a slightly superior camshaft.

However, as Piper are able to make the long bolt mod, they will naturally only want to use their own products. So unless I can find who makes the QED420 or a shop that will make the modification, I will have to go Ultimate.

Should I do this, the Q55s are compatible?

"So unless I can find who makes the QED420 "

Try QED!!! D

I don't know who grinds the cams for QED. But I am sure that Piper would modify a QED cam for you if you asked them to modify it for the longer sprocket bolt. There are enough QED420 cams using Q55 springs out there being used and most I presume don't have the long bolt modification as QED don't do it or know about it, so that combination at least is probably OK

The Q55 springs should work with any cam up to around 0.420 lift and standard length valves and standard cam base circle if limiting to 6500 rpm. Though when modifying any Twincam or even when building a "standard" one you do need to check dimensions and clearances for the valve train components selected and fit for your individual head as things get changed over the years with previous work sometimes doing strange things

The Kent Cams L14 is a similar specification to the QED420 also as an alternative.

cheers
Rohan

You can get the QED420 cam from QED in steel. These will be plenty strong and you should not need the long bolt mod. I was assured by them that these work fine in combination with their steel followers (we shall see....). I know Newman Cams do offer standard cast followers.
QED offer the QED420 cam based on a new cast billet too. For a road engine not subject to sustained high RPM I imagine these should be perfectly fine

Yes there are lots of possible cam and follower material combinations and most have trade offs. There is no perfect solution. I was not aware that cast iron followers were still available

Cast iron cams on cast iron followers is the original design and wears well but you need the long bolt mod if using high lift cams and high revs. The cast iron followers also cant be used with many high lift cams as they are to thick when you need to use longer valve stems to get acceptable spring loads and a thinner follower. The cast iron follower can also break in high valve lift high rev engines

Steel cams without the need for the long bolt modification and steel followers give you the strength and acceptable follower dimensions are available but there are significant galling issues to be overcome with steel running on steel. DLC coatings on the followers and phosphate coating on the cam and careful selection of springs loads can generally overcome these problems but not all the time and it appears to be a bit hit and miss on what works and does not fail during running in

Cast iron cams with the long bolt modification on steel followers work well in my experience for even extreme race applications of 0.49 lift and 9000 rpm provided valve loads are within allowable limits.
Phosphate coating the cam and DLC coating the followers does not hurt but does not appear to be essential for reliable running in of this combination

Steel cams on cast iron follower should work OK but I have never tried it and it would be limited to a relatively low lift low rev road engine

cheers
Rohan

OK! Result!

Spoke with Kent Cams. They know all about the long bolt modification and can/will do it without any problems and not expensive. He wants to know more about Col's bolt as he is not sure why it is so long, but could be an optical perspective issue.

Kent make cams for QED. They have a similar own brand to the Q420 which I shall use, as QED are still dithering on answering my questions.

Some comments from them whist on the subject:

They say a steel cam will not break. On questioning them about steel on steel followers, they say not an issue if Kent followers are used - types of steel, treatments etc. But they say this option is unnecessary unless I am going full race 8000RPM+

They further say that a cam without an oil groove should not break. Comments Rohan??

They can/will supply cams without the oil groove and leave it up to the customer to groove the cam cap/bearing. This of course needs another machining operation, which for me is an issiue, so, because machining the long bolt option is so simple at manufacturing stage, They suggest that I proceed with this.

HCA wrote:OK! Result!

Spoke with Kent Cams. They know all about the long bolt modification and can/will do it without any problems and not expensive. He wants to know more about Col's bolt as he is not sure why it is so long, but could be an optical perspective issue.

Kent make cams for QED. They have a similar own brand to the Q420 which I shall use, as QED are still dithering on answering my questions.

Some comments from them whist on the subject:

They say a steel cam will not break. On questioning them about steel on steel followers, they say not an issue if Kent followers are used - types of steel, treatments etc. But they say this option is unnecessary unless I am going full race 8000RPM+

They further say that a cam without an oil groove should not break. Comments Rohan??

They can/will supply cams without the oil groove and leave it up to the customer to groove the cam cap/bearing. This of course needs another machining operation, which for me is an issiue, so, because machining the long bolt option is so simple at manufacturing stage, They suggest that I proceed with this.

Exactly where the cast iron cam will break and in what circumstances is debatable and something I dont want to experiment to much with

I have seen them break in others engines at the oil hole / groove and just in front of the bearing. I broke a cast iron cam in them middle when when I had the rod failure in my avatar and the piston drove into the valve braking the cam

WIth a Q420 cam and Q55 followers and 6500 rpm limit your "probably" OK. But if I was doing it even within those constraints I would do the long bolt modification as I have learned from long experience to be conservative with this sort of thing.

If Kent cams can supply a similar profile with the long bolt modification to a QED 420 then that's a good option. The Dave Bean Drawing shows the modification they do to the cam to carry the bolt past the bearing and the ElanTrikBits bolts fits this as far as I am aware if Kent cant supply the bolt or I presume Dave Bean could supply. i would get the bolt first then get Kent cams to tap to suit. i have made my own bolts so not hard if you have access to a lathe.

When building a modified engine you need to work with a range of suppliers as no one has all the answers in my experience and what they say needs some careful interpretation and engineering questioning which most cant answer

Steel cams on steel followers is an example of one of the things most don't understand except perhaps Tony Ingram who can supply DLC for the followers on request.

cheers
Rohan

I have played with the long bolt modification for many years in many cams and have a few spare examples of the bolts I have used from various suppliers over the years. I will dig them out and post when I get a chance.

I have never machined the groove in the bearing shell rather than the cam and don't think I would want to go down that route or that it is needed but others may differ

cheers
Rohan

Note QED supply their chilled cast iron cams as part of their FIA racing engine upgrade kit. I'd expect they would have supplied steel cams as part of this kit if there was an issue with camshafts breaking. It may be that the grade of chilled cast they are using is better than what was used originally (but that's only guessing).

Either way I'd be interested in hearing the experiences of any UK FIA racers using QED cams be they cast or steel. I'm sure there must be people out there who have purchased these cams from QED in the past.

https://qedmotorsport.co.uk/product/fia ... grade-kit/