cams

[MACCA.GLM]

Hi
I am a new member so please excuse me if I make mistake. Anyway I have an Elan sprint DHC which I bought with
lots of new parts. Engine and gearbox rebuild to £15000 in 2018 and is in excellent condition of just a standard sprint with sprint cams 2 lines. The engine looks like it is ported but not polished.Has anyone got any info about maybe putting a faster set of cams with verniers maybe from QED ie 420 lift and weather it would benefit in power.I don't want to spend a lot of money and I can do the job myself.
Thanks

[rgh0]

viewtopic.php?f=39&t=52339&start=15

Have a read of Chapter 6 on cams and valve train

cheers
Rohan

[gherlt]

Welcome !
May I ask if you already drove the car around "interesting" roads ?
I ask you this because quite a few people ask for more power before driven the car.
The Elan has enough power, modifying for more usually does it not make it better (or more enjoyable) in 90% of its use (and I exclude "around city" from this). If you do only trackdays, then I do shut up.
But as you say, you don't want to spend a lot of money, when you up the power you should a look of the rest of the drivetrain, which is not cheap to modify either.
I would live with the car for certain time and do a shake down and then look what could be better. But be prepared to spend ...

[MACCA.GLM]

Hi both
Thanks for the replies.
1/ I do not intend to track the car so used on country roads etc so I will take your reply into consideration
2/ I would like a little more acceleration so the cam article by Rohan is brilliant well done.However if I put a say 420 lift from QED would there be a need for head mods as in new valves (bigger)head polishing port mods and bottom half strengthening. if this is the case I will leave it alone and take Gherits advice.

[rgh0]

The QED 420 cam and Q55 springs will fit in an other wise standard head and produce good results to 6500 rpm without porting or larger / longer valves

There are betters road performance cams but they require more modifications to fit

cheers
Rohan

[MACCA.GLM]

Thanks Rohan

You obviously know what your talking about. So question 1 is would there be a notable performance increase from 126bhp if I went down the QED 420 with springs q55 route ,without head mods.

I would like around 135 to 140 bhp

2 If i took another route as you said another make of fast road cam.what head mods would I need to do and who would be a competent engineer to complete those mods.

regards

[rgh0]

The QED 420 cam will get you into the 135 to 140 hp range on a standard or slighly overbored twincam. You can get another 5 to 10 hp into the 145 to 150 hp range without porting with higher 0.440 inch lift cams of similar duration but these will require longer valves, suitable springs and thinner followers. Its always a good idea to fit new followers with a new cam in any case.

Porting the head will get you another 10 hp at the top end and into the 150 to 160 hp range but this starts to be expensive for a twincam due to the long fixed intakes and you also need a larger exhaust. Head porting also does not do much for midrange torque so its more for trackday use than road use.

All these HP numbers are very approximate and assume the rest of the engine is in top condition and things like cam timing are done accurately and the engine is properly setup on a dyno

cheers
Rohan

[HCA]

I am going to jump in here to say welcome and listen to Rohan’s advice as he is the font of knowledge here!
Also, because I am in the middle of building a tc engine using new parts throughout with a John Wilcox head as the base. It is ported and polished with 34mm throats. It might be worth measuring your throats to see if they are enlarged.
There is a tuner/racer in the US, Tony Ingram, who like Rohan, knows his twin cams, who is interested in my using a ported head (his ‘own brand’ head is the same as John Wilcox) and reckons there is a ‘large slug of air to move’ surmising that it needs csreful cam selection… I am using Kent D44 cams that are a 420 equivalent that Rohan is assisting on assembly and timing.

What I am saying is, confirm the existing engine spec and from this in conjunction with Rohan, determine what cams are best or if indeed another mod is better - eg injection. If though you say you have 126bhp, do you really need more?!

[MACCA.GLM]

HI both and thanks for this.

The engine is in excellent condition but as I had a problem with the release bearing failing I had to whip the engine out. while doing this I noticed some oil leaks so I completely re gasket everything and resealed where possible.i also took main cap and big end cap off to look at the journals. All in great condition so happy with the work done.

I think I will take your advice Rohan and go for the QED420 set up as its minimal work with a good result and they are on my doorstep. Do you advise the chilled cast version?.

would I also need verniers as using offset dowels seems a bit of a ball ache or do you think the timing should be ok.
The timing marks are perfectly aligned at moment.

I also must say you have bought back a little bit of nostalgia as you mention a guy called Tony Ingram.He did the head for me on my elan around 35 years ago at his company Twincam Techniques. He did a great job and I got to know him quite well. I know he went to the states but had no idea what he was up to.Do you have a contact address for him.I would like to drop him a line.

thanks both for this info

[rgh0]

Look up Lotus7.com which is Tonys website.

The timing on the QED 420 cams is different to standard ( and wrong in the QED literature the last time I looked) so adjustable sprockets are really required to set the timing correctly.

I would use cast iron cams and new cast iron followers

cheers
Rohan

[MACCA.GLM]

That's great Rohan

Thank you