Will my head be good or bad on a 1900 bottom end?

Guys,

I have Mike Lanes old engine which develeoped 213bhp when originally setup by Emerald.

It has the following head with a totally standard bottom end.

DVA Power modified head (full porting)
Piper 1227 cams
larger inlet valves in Colsibro guides
double valve springs
steel caps and solid followers

The bottom end is rather tired and in need of a refresh. I was considering having Scholar rebuild the bottom end as a 1900 and put this head and cams back onto it, with a top end refresh as required (head only done about 10k miles)

Good idea, bad idea? Wrong cams for bottom end? Looking for advice really.

Or other ideas gratefully recieved. Must be K Series based, Exige is without doubt a future classic and I dont want to go down the non K series route.

Ric

I would say it would be ok, but in order to extract the full potential of the 1.9 bigger pistons you could now go for bigger valves. But that’s a lot of work on the head: new valves, machining, valve seats, porting to take advantage of the new area, etc.

But the only problem I see is that bolting the head straight on a 1.9 you would be automatically be raising the compression ratio (more volume being compressed)
Check the volumes well to prevent detonation.

I’m sure Dave would be here shortly to tell you how much it would raise, maybe it’s within limits.

The valves fitted to the head currently will flow enough air for 245BHP+ so unless you are aiming for higher than this they should be fine, the head will be well suited to a 1900. The cams are pretty good but there are some better profiles available which will give more torque and a little more power. The head could beenefit from some work on the chambers to suit the larger bore and put the compression at the correct level, it will be around .5-.75 of a ratio higher on a 1900. Even if you dont upgrade the head, it’s still worth replacing the stem seals and checking the follower gaps and guides.

Dave

Never even thought about the compression ratio issue, more swept volume!! Obvious really (well when someone points it out)

I’m not really sure where I am aiming in terms of power, the standard answer would be as much as possible and 100,000 mile reliability.

Realistically I want an engine that dosnt need refreshing after one season of say 7 or 8 track days but am realistic that after say 2-3 years it would come out and be looked at.

Given the work you talk about is carried out on the head and the cams replaced, what sort of (very ball park) figures would you expect it to develop?

I notice on another thread you talk about injectors being nearly at capacity, is this likley to be an issue?

Ric

I’m not really sure where I am aiming in terms of power, the standard answer would be as much as possible and 100,000 mile reliability.

Realistically I want an engine that dosnt need refreshing after one season of say 7 or 8 track days but am realistic that after say 2-3 years it would come out and be looked at.

Build it very carefully and balance it well.



I notice on another thread you talk about injectors being nearly at capacity, is this likley to be an issue?

Definitely, in my experience anything above 220 BHP needs some revised injection, be it larger injectors, higher pressure ro both.
And a std pump can probably keep with some 220-230 BHP, but it’s not going to last a long time so reallhy need to look at some impreoved fuelling, either a swirl pot and extra pump or (like in my case) an upgraded in tank pump and fuel pressure regulator set at a higher pressure (4 bar for me)

BTW, I received some enquiries from people that (like me) would like to avoid an external swril pot and pump setup, preferring the in-tank fuel pump I use.
I thought of posting what I have done for the benefit (or not ) of all:


The main problem is that it’s a DIY thing, nobody currently makes a kit for this, and they won’t, because of a pinhole.
Basically it’s a Sytec 340 pump (I think, could be 341 or 342 as in the chart I have they’re all the same).
If you need the Pressure Vs flow chart get in touch with an email addy so I can send it.

The problem is that it’s a single stage one, there are absolutely no dual stage pumps that we can use and the Lotus jobbie is good at keeping it simple, but built of plastic (yes, even the internal gears) so it loses pressure quickly with time.
Not a problem when it’s got 118 BHP to feed, but a problem when they’re more like 220!
Also tried the S2, 111R pump, which is rated better but has a different loom, connector and electronics. Tried the VX220 pump as well, but it’s a single stage one that has its own problems.

So kept refining this one to the point that I no longer get any fuel starvation while cornering.

Basically it’s like this:
-remove previous pump from the white plastic (doh!) with external filter
-make a sleeve to adapt the new, bigger pump to sit inside (no external pick up anymore).
-lower the white plastic canister by thinning down the rubber feet to approx only 3mm from tank floor
-plug pinhole on the fuel return leg (used Mylar tape, spring on top keeps it tight)
-reduce overflow hole on top by installing a rubber grommet (hope the rubber was fuel-resistant)
-avoid parking on slopes tilted to the right (just in case).

This way the fuel will be picked up by… well, just because it’s around it.
As soon as the pump starts it will be picking some more fuel from the bottom hole (both of them with their rubber check valves) and circulating it through the fuel rail.
The return will be dumping it inside the canister where it’s going to have a hard time escaping (precisely because the rubber check valves are still there and because the overflow hole is very small now)

There is one drawback to all this, and the reason why nobody will be able to offer this as a kit to the public: the pinhole.
We blocked it, remember? this little hole prevented fuel from being pressurized and sent up the pipe when the tank is disconnected.
With this plugged, as soon as you’re bolting the pump, fuel vapours will start pressurizing the tank, and the ONLY way to escape is precisely sending fuel up the hose (it used to be vapour thanks to the little hole, but it’s not there anymore).

So basically fuel will be pouring from that pipe as you’re bolting the pump down (you need to have the pipes disconnected at this time in order to access the nuts) and need to be quick connecting the “quick” release fuel pipe connector.

Would recommend not to smoke while you’re doing this, and for the next day around the car. Actually, it’s a good excuse to stop smking altogether.

Other than that once the pipes are plugged the system is perfectly sealed and there are no more fuel starvation problems even with a single stage pump.

HTH.

Uldis

Hi Ric

Nice to hear that the old girl is still going strong (even though she has a tired bum - er - I mean bottom end! ).

Must get together some time to catch up - you still living in that mansion with the 8 car workshop??

Yes she is still going! Off to the ring next Tuesday so hope its tired bum keeps a turning a little longer. Yes still living in the same place, let me know if your about your always welcome for a cuppa.

Spoke to Scholar today - They are collecting the old engine on Wed to rebild as 1900 !! Balancing etc…

Need to speak to Dave now - Dave if you read this can you PM me or email so we can take it offline.

Will keep you all posted with the progress of the project.

Uldis, Fuel pump sounds exciting Need to establish where I am aiming in terms of power I guess but I would hope more that 220 given the 213 on the 1800 bottom. Will PM you with email

Wish me luck - I think i’m on a steep learning curve. I can take an engine out and put it back in without problems but this should be a bit more challenging.

Now where was that torque wrench?

Ric

good luck and keep us posted

Yeah - Interested to hear how this goes …

I use the same fuel pump (I think - well its certainly a single stage), and solved the single stage pump issues and priming of the plastic plenum by welding a block onto the front lower corner of the fuel tank half way across the tank. This was then drilled and tapped and a pipe fitted that went to a small aux fuel pump (from a Rover 214 IIRC), the output of which feeds the plenum. The priming pump is held in place by one of the bolts that fixes the plastic plenum into the tank and there is enough room for it between the top of the tank and the chassis.

The return from the injector rail is also returned to the plenum rather than the into the fuel tank. There were concerns regarding fuel temp but this has not been an issue for my install, used on the road, track and hillclimb competition.

What this setup allows is for the tank to almost be run dry without fuel starvation - so I can run a virtually empty tank when competing to keep the weight down

Also there are no safety issues so I could take up smoking if I wanted to!