DIY Porting for an idiot

[robin]

Read Dave Andrews' K-series engine page for all the details on modifying the head.

I am sure that you will regret the 300s without DTHTBs. I know from personal experience that fitting DTHTBs to an S2 isn't trivial (nor cheap). If I were you, I would be going for the Kent 1812 or Piper 633 ... you can make very respectable 180BHP if you do well with the porting and tuning. That makes for a great driving car with plenty of power and still reasonably reliable.

2p

Robin

[Rich H]

Are 633s the older grind of 270/275?

As Robin said anything wild will need serious investment, thats why I bought the Porker to give me a cheap alternative to tinker with!

[robin]

I think 633 is the current grind for 270's - the older 270's were a bit rougher on the idle I think.

Cheers,
Robin

[steve_weegie]

2p received with thanks Robin Just FYI, dont have the complete VVC mech so am stuck with a solid cam conversion. With the 270 grind, is there a chance that the stock ecu will run this with a tweaked fuel regulator, or is it a step too far? If so, It would certainly swing me in that direction.

Rich, I know the waterway you're talking about - DVA mentions drifting in a bit of alu rod into the inlet side so its possible to shape the port divider correctly. A small bonus is that the VVC casting doesnt have this on the inlet, so i'll be able to grind away happily I've got bits of a top end gasket set (robins actually - not forgetting BTW ) in Haddington so will retrieve the inlet and start there. I guess working on the inside is going to be less fiddly than the combustion chamber, but poor access and visibility are going to replace the fear of valve seat contact from here on in

Pics so far:



Yup, its a sorry state....



Cleaned up well me thinks



The d.i.n.g.s, ground out as best I can / dare.

[Rich H]

Is that damage in the bottom pic?

Get the gasket marked out and then grind out to that first, that will keep you out of trouble for a few days...

[steve_weegie]

Yup the broken valve heads made contact with the 2 areas round the exhaust ports and I ground down to change the nasty jaggy bits into curves. The mark on the face is another hit, but i've not done any work to that.... I was going to leave it and see if any work needed done after ive had it skimmed.

Keep out of trouble? Me!?? I'll get the gasket and see if it helps

[robin]

I doubt your stock ECU will cope with 270s and the VVC head - though it may run, it won't be pretty. The problem appears to be that the K4 ECU is much more sensitive to pulsing in the manifold (or maybe it is just because the MAP sensor is in the plenum rather than on a long bit of fish tank hose).

Ask Ali if he wants to sell a VVC mech or two - I'm sure he must have a couple by now If you have a choice between a VVC mech and 270s, I would get the VVC mech.

Cheers,
Robin

[roadboy]

633s are the old BP270 grind. They are the ones that are rougher at idle compared to the new slighlty lamer 270s.

Dan@JPS

[steve_weegie]

Robin, Ali gave me this head He said he might have more bits for it, but i'm happy to go for the single cam conversion in preperation for Project Powerquest in the future

[robin]

633s are the old BP270 grind. They are the ones that are rougher at idle compared to the new slighlty lamer 270s.

Dan@JPS

Ah - thanks Dan - I didn't realise that - any idea what the new grind number is then? I'm sure there were 270's before the 633s (i.e. even older). Anyway, I guess the point is to buy the current grind if at all possible!

Cheers,
Robin

[steve_weegie]

After a bit more research, I believe there's a few grinds between the 270 and the 285 too, like the 1320 thats not on the piper list. I'll get in touch with them and see what the script with these is too

Cheers,

Steve

[roadboy]

1320s are about as far as you can go on a plenum if you want it to idle. Pretty good cam to be honest. I'd recommend them for anyone who wants a fairly high state of tune without doing the bottom end as they make their power lower down the rev range than 285s, which are a bit of a waste unless you're prepared to rev to 8k.

Robin, not sure what the new grind number is. I would recommend the 633s over the new 270s unless you don't want to run verniers. If you run verniers 633s will idle fine and make more power than the new 270s.

Dan@JPS

[Rich H]

Any way of working out which is which?

I think I have 270's (That is what I was sold them as) but I dunno if I actually checked anything... Would it just be a case of measuring them then checking against the piper list?

[steve_weegie]

Dan, thanks for the info - very helpful indeed

Spoke to piper today so they will be sending up the specs of the 1320

[davidbrown]

Hi,
I am an interloper from Scottish 7's but have been watching this site for a while. I have a 1.6K Caterham with 633's, verniers, 52mm TB and am currently porting a spare head (not VVC) for Jenveys and an Emerald, so watching this with interest. My understanding was that the VVC head wouldn't accept normal cams as the journals were bigger - but I may be wrong.
David