Forged pistons/1900 cc

[DaveK]

Hi folks

 

Having now been tempted to modify the Elise engine, by fitting a set of Piper 633 cams (Thanks Richard), i'm know tempted to go further and build a 200 bhp engine for the car.

 

Two questions ,

 

Forged pistons, which are the best make, and what price should i expect to pay.

 

1900cc scholar block , will this make much difference on a 200 bhp cooking spec engine over a 1800cc engine.

 

thanks

 

Dave

[Shaun_E]

Scholar block has 2 things going for it:

1) Eliminates any issue with liner heights

2) extra 100c not to be sniffed at

Having made that decision you then don't get much choice in pistons. Scholar provide Pistal pistons (which I have in my engine) but these are a "slipper" design which I understand means they have a very short piston skirt. It makes them very light but they should really be inspected regularly (depending on usage). Just after my engine was completed, Omega developed an 82mm piston for this application and I would probably have gone that route.

My target was 200bhp and with Jenvey's, BP285H cams (hydraulic lifters retained), DVA Power full porting job on VVC head, Bernard Scouse airbox, Caterham VHPD 4-2-1 exhaust and an Emerald ECU the engine made 227bhp and 167lbft on Emerald's rollers.

 

Yellow SL #32 - member of Drowned Rat Racing

[DSL]

Dave, Scholar block & pistons cica £990.

 

The pistal pistons are a very nice looking piece of kit & Dave Andrews has no real reservations against using them

 

Also with the added benefit that the piston to block incompatabiltiy of expansion / clearence issue I had with my Hellier built engine should be avoided ☹️

[Sheds Moderator]

I'm not an expert but you can get 200 bhp without the expense of a 1.9 block. A 1.9 will give more torque than a 1.8, all other things being equal, but IMO 1.9 is an expensive way to get "only" 200 bhp.

[Nifty]

However BOSS, if you want to have Scholar do their trick woith the liners then it's a no brainer to turn it into a 1900 whilst you're at it, giving the extra torque and future upgraditis ability

 

Keep off the straight and narrow 😬

[Nifty]

Dave,

 

If you do decide to go down the Scholar route give me a shout.

I live just up the road from Scholar and my sister lives in Pen-y-fford just north of Mold so I could help out with transportation

 

(Of course, it will cost you a staff discount on a few bits )

 

 

P.S. Thanks for the parcel, it arrived yesterday

 

 

Keep off the straight and narrow 😬

 

Edited by - Nifty on 22 Aug 2007 19:21:51

[DaveK]

Thanks for all the replies

 

I was only thinking of the 1900cc conversion as it not much more than the cost of a set of forged pistons, so it makes sense to do it at the same time.

 

Shauns spec it pretty similar to the spec i was looking at with the 285 hydraulic cams, as i really want to fit and forget and not have to rebuild every year, so if 227bhp is the figure i'd be happier than the 200 bhp baseliner

 

Its all cheaper than fitting a Duratec in the back of it though which was the other option.

 

Dave

[Richard Price]

Shaun,

Is your engine running standard VVC valves?

[Shaun_E]

Richard - yes they are standard VVC valves (which are the same size as the VHPD/MS2 ones).

Dave Andrews did a full porting job on the head and the throttle bodies are port matched as well. Obviously the VVC mechanism has been junked and a Piper blanking kit fitted. It's a fantastic engine - great on the road including trickling through traffic yet has plenty of go for track/sprinting. I would have chosen the Omega pistons only because they would have made the engine even more fit and forget than it is.

The temptation to go to solid lifters and wilder cams is ever present but this would reduce the tractability for road use, significantly increase the stress on the engine and require more regular refreshes.

 

Yellow SL #32 - member of Drowned Rat Racing

[Sheds Moderator]

[stands corrected]

 

Hi Nifty, I didn't realise the 1.9 was just an overbore with new liners, I thought it was a bespoke job or at least a stroked crank. That makes it more reasonable if you are going down the road of forged pistons anyway (as you surely would north of about 180bhp).

 

If you can use the original crank and you are going to play with pistons and liners in any case then it might not be a much bigger cost after all. 😶‍🌫️

[Shaun_E]

Some infor here on the Scholar block.

 

Yellow SL #32 - member of Drowned Rat Racing