DVA K13

[Julian H]

I am looking forward to October when my Seven is booked in with Dave for K13, verniers and forged pistons  using some Supersport cams (temporarily until I get the TB's and ECU to go with some hotter cams).

Kit 13 comes with 29.5+26mm valves and springs to allow up to 11.5mm lift. i wonder if I am selling myself short for the future and, whilst I am having this done I should get head mods with more potential, if that next step is not too expensive? I do fancy more than the 200bhp in the longer term that Dave states K13 offers.

Thanks for your wisdom.

Julian

[Titanium7]

The orginal R500K's at 230BHP had an all steel bottom end I believe also you may want to consider a Dry Sump system.

[Mankee]

Surely the next step up from a K13 head is solid lifters, double valve springs, humongous cams and ginormous valves = massive dent in the wallet? I would stick with the K13 head from Dave (as well as the bottom end work) and see how you get on with 200bhp, as it's a LOT of go in a Caterham, especially for road use. And then consider whether you want to stick with 1.8 or go 1.9 if you want more power later on. Standard rods and cranks will take a lot of punishment if they've been prepared properly.

[Julian H]

I may consider a dry sump, if a develop a taste for trackdays in the future.

I realise that 200bhp is a lot in a Seven. I am confident I will not regret the K13 kit at all, in fact I am sure I will love it and am really looking forward to having some DVA DNA under my bonnet . However, I wanted to ensure I was not doing something where a little bit more may prove more sensible in the long term. I have read threads, many of which with Oilys contributions and I think I would like 1444 cams. Without much redundancy, could I run those cams in the K13 head? Are the valves as good as I can sensibly get in my head? 

I would contact Dave himself. I have already spoken to him on several occasions now and we have had much email contact since I booked my slot but I don't want to keep bothering the poor chap with my pesky questions..., appreciate any informed opinion/advice.

Thanks.

[oilyhands]

Hello Julian,

A few points..

You will initially be running with supersport cams, single Piper springs and steel caps with clearance cut for a later upgrade to BP285H cams. To upgrade later to 1444 cams instead will require the head to be lifted to change the springs and caps, you would also need solid followers and shims with 1444 cams which , when taking the head removal into account as well will increase the cost of the next level of upgrade by a fair bit.

The valve sizes used on the K13 head together with the porting are good for around 200-210BHP with the right cams, if you wanted larger valves then the head will need larger inserts which again will increase costs considerably.

If you did decide to go with larger valves/inserts and 1444 cams you might see 220BHP, a little more if everything is right and you are lucky.

A good compromise might be to go with BP300H cams at the second stage which will still run with hydraulic followers and single springs but should give a little more than the BP285H cams.

Oily

[Julian H]

Hello Oily

Taking on board your comment of increasing cost a fair bit for bigger valves, and requiring head off and other new bits and pieces, I think my forgoing that option would be sensible! I don't recall having seen the BP300H cams mentioned before; looking them up on Piper's website I see I could choose a solid follower lower spec cam initially [ARKBP270M?] which will still work with my standard plenum and ECU. If I decide not to go with the Supersport cams would this give me a simpler/more cost effective route to 1444 in the future?

Thankyou

[oilyhands]

The 270 cams are a weak option, a downgrade from the SS cams power wise, you could stick with the SS cams and use solid followers with double springs in readiness for the 1444s, but I think the BP300H would be the best option all round in terms of price/performance.

Oily

[Julian H]

Hello Dave

As you may imagine, my head has been in a spin regarding my choices. If I can see between 200 and 210BHP (and a nice torquey response?) with the BP300H with the head as it is that I think I would be best served taking your advice. My reservation is that I have read many posts where the experienced advocate the 1444's (and the lower BP285H) but little on the BP300H?

Julian

[Grubbster]

I don't want to hijack the thread, but I've never really understood the cam numbering, I have 1227 - how does that compare with 1444s or BP285H / 300H?

[Mankee]

I don't think the numbering has any relevance to anyone except for the profile design department! The Piper specs are here, in case you've not seen it:

http://www.pipercams.co.uk/pipercams/www/product_nav.php?type=C&cat=CM&man=20&engine=194

[oilyhands]

BP285H and BP300H are standard offerings, hence the duration based nomenclature, 1227 and 1444 are development grind numbers

1227 are around 280 degrees with 11.6mm lift

1444 are 276 degrees with12mm of lift and a very fast lift ramp so the area under the lift curve is larger

In practice they are similar, the 1444s give a little more power and a wider beefier torque curve.

The progression curve is

BP285H, BP285M, BP300H, 1227, 1444, 1721, 2180.

 

Oily

[Grubbster]

Thanks Mankee and Oily, appreciate the info.  I feel really 'under cammed' with my 1227s now ;)

[Superwhite R283]

I disagree Steve  

[johnv]

We love 1227's :-)

[oilyhands]

As with all things diminishing returns set in, the 1227 was the cam of choice until the 1444 came along, 1444s are a little better but harder on the valve train and they require more preparatory work on the head. It's not worth trading up if you have 1227s, the gains are too small. Anything above requires more RPM and will narrow the torque band so unless you fully extend the engine (8500 plus) then the car would be slightly slower, again the cams are harder on the valve train and the RPM will affect reliability and longevity, anything above 1444 would ideally have steel crank and rods and larger REC valves and the owner would need commensurately deeper pockets. The 1227/1444 level is a sweet spot.

Oily

[simonpa]

I've had Oily's 285M setup in an early Superlight and it was by far the best 7 I ever had.
Responsive, plenty of torques, easy to drive on the road and bonkers enough on track.

Since then, I've had a variety of other cars, including 2 x R500s.

The R500s had the standard 1144s and roller barrels.
TBH, although fantastic to drive anywhere, they were a pain on the road, partly due to the (relatively) lower mid-range torque, plus the trigger throttle make town driving 'interesting'.

On the open road, you either use the power (and p1$$ off a lot of other road users), or spend your time wondering when the next failure might happen and land you with an engine rebuild (didn't happen to me, but I still worried).

Anyhoo - my advice is to listen to Oily - he knows his stuff!

If you decide you 'need' to play the numbers game, though, I have a 2180 cam in the drawer, that I'll probably never use now...

Cheers - Simon

[Julian H]

Wow, so much information to take in! I am pretty comfortable taking Oily's advice, and have done so all the way through my decision making process, despite my wobbles on insecurity. I am not sure what cams I will go for but I know I won't be going the solid route so Daves K13 head will do me just fine. Dave I will be in touch shortly.

Thanks, Julian