65 replies to this topic

[stevegrabba]

Morning Guys,

 

 

I have a road going 1340 with a SC 7 port head, fitted with their throttle bodies, fuel injection and full exhaust system from the manifold.

 

CR is 10.5:1 and it is fitted with the RE13OT camshaft, 1.5 roller rockers set cold at 0.019"........(I'm double checking that it may be the RE13PP camshaft!!)

 

Its been on a few different rolling roads and afterwards they have all said that they struggled to get the stability in wide band lambda fueling values that they were looking for when building the fuel mapping base maps and then all the correction multiplier values which then follow.

 

I've thrown a few theories round in my head such as the short inlet manifolds/throttle bodies not creating a consistent fueling mixture ratio and other thoughts, however I kept going back to thinking about valve clearances/tappet settings.  Finally I was thinking that ....over the years there have been many cars which have benefited massively by having a different clearance value on the inlet compared to the exhaust.....2,3,4 or even 5 thou etc.

 

A little later this morning I'm gonna give SC a call and poise the question, however does anyone have any thoughts or theories about whether it's worth a try opening up the inlet or exhaust valve clearances a 2 or 3 thou to see what happens?

 

 

Cheers! 

Edited by stevegrabba, 25 February 2019 - 09:04 AM.

[Retroman]

So having "been on several rolling roads"  is it not running correctly ...???

 

I would have thought if anything that the valve clearances want tightening down at least 3 or 4 thou from 19

 

Try at 0.015" and see, surprised a RR operator has not tried it.

 

Surely an injection system can cope with pretty much anything and adjusting the tappets should be well within any parameters.

 

Altering the tappets does alter the timing and air flow characteristics and the system should alter the fueling to match.

 

The short inlet tract is what it is and the injection should cope

 

and alter the fuel to match the air demand and various other parameters

[stevegrabba]

Its not running bad at all, its just that as an owner of numerous minis of varied specs...I get the feeling that it should be running much better.

 

Bearing in mind that its an alloy billet head which would be expected to expand more when hot......are you saying do both 'inlet and exhaust' what is your theory behind tightening the tappets up a bit?

[Retroman]

Not sure with your cam what clearance the tappets should be, but working off 12 thou on standard rockers, with 1.5's  opening out to 14 or 15 won't be far off, I would try both at 15, I think 19 is too wide.

When they are opened up it tends to make the airflow pulse more which may or may not work.

 

It is something that should probably have been tried or considered on the RR as they are so wide it would have been worthwhile adjusting them down just to try it, and the operator should have suggested it.

 

We have just run a MiniStox race engine on a dyno [not RR] I built the engine with 12 thou tappet clearance and suspected it may work better with them wider, tried them at 10 thou and lost 2 hp right across the workable revs...So tried at 13 thou and didn't gain anything significant.

Had we had time we would have tried them at 14 and 16 thou and different inlet / exhaust too, but at 100 quid an hour us peasants can't do everything.

I have seen similar engines also professionally built and tuned running .008" tappet clearances. But with a similer lift/duration cam ground on a wide LCA and timed very differently. Each and every engine is different and small variations can make gains and losses at different revs and its not always predictable.

That is why the only way to get the best from every single engine be it road race or rally is a dyno or rolling road session....with the proviso that the operator has to be top notch too.

[sonikk4]

What size injectors have you got fitted?? I Have asked for the smaller 220cc injectors for mine rather than the larger injectors that they come with as standard. I was recommended this by someone else on the forum who had fuelling issues with their 7 Port set up.

[mini13]

head expansion wont have much of an impact on valve clearance, infact it may open them up a little but basically negligable, maybe a few tenths of a thou?  as mentioned i'd be expectingaround 15 thou clearance.

 

I'd be looking for anything in the software that changs the mixture, ( closed loop idle) and turn it off to start with. also lambda delay settings can affect this.

[stevegrabba]

Thanks for the input guys!

 

 

First bit of an update according to SC the recommended tappet setting is 0.016", for both the inlets and exhaust and it is the RE13PP (Calver Road Super Sports) cam.  However according to Keith Calver they should be set at 0.020" at running temperature.

 

Of course resetting the tappets is a 10 min job which I've done now already at 0.020" and there is an improvement in the stability of the fueling values according to the AFR gauge already in the car already.  The car also runs much more smoothly too during moderate and hard acceleration.

 

I'll have another fiddle tomorrow and turn off the closed loop idle and lamda delay settings (If there are any).

 

Likewise comments noted about the injector sizes.....that's something else I'll look into too.

 

 

Cheers guys!!

Edited by stevegrabba, 15 March 2019 - 08:17 AM.

[Retroman]

Ok Good

 

A step in the right direction, worth trying them at 15 and 14 thou and see if you get another improvement

[Cheeser]

I run a 1380 with well worked 5 port head, twin HS4 and re13ot with 1.5 rockers. After a few changes to inlet manifold and ignition advance curve I also opened up the valve clearace to 20 thou hot, as recommended by Calver and found that the engine generally runs much better, I had previously been running at 17 thou cold. I know the improvement may not have been down to the increased valve clearance, but I would have thought a chat with Keith, who supplies these cams could be useful?

[sonikk4]

stevegrabba

you have a pm bud.

[InnoCooperExport]

Just a really stupid thing to say but you are measuring the rocker clearance properly? I saw you have roller rockers installed, just to make sure. You should always measure the clearance between rollers and the valve perpendicular to the direction of the roller. So as you don't roll the feeler gauge between the valve and the rocker, but rather come at it from the side. Measuring adjacent can cause the feeler to get squashed between the tip of the valvestem and the roller causing the reading to become inaccurate. Just something to bare in mind. 

[stevegrabba]

Thanks guys, a lot of helpful hints and ideas. 

 

I am leaning towards trying a different size of injector, but to be honest I don't know what the existing size is.  Are they generally colour coded or marked in any way to identify their size?

 

What would you expect the cost to be for a set of 220 or 330cc injectors and where would you get them from?  SC??

 

InnoCooperExport......yes that's what I have been doing when setting the roller rockers.

 

 

Cheers again guys!!

[stevegrabba]

Just found this post from a few years ago too......same cam, and he says that he was getting stable AFR readings and was using 250cc injectors.

 

I sort of hope mine are 440cc so that I can point the finger at a potential cause...

 

http://www.theminifo...megajolt +cable

[stevegrabba]

We are getting there guys.....the fuel injectors are BOSCH part number 55556799.  Which a quick Google suggest are commonly fitted to a Vauxhall Zafira VXR  2.0 Turbo, which probably demands a little bit more fuel than my mini!!

 

Can anyone offer a little guidance that will help me select the correct fitting and size of injector so that I can get these out and replaced ASAP?

 

Cheers!

[stevegrabba]

Getting closer again....the injectors currently fitted are actually 480cc.  The injectors that I am being told to use are nearer 180 to 200cc, with the suggestion of injectors from a Ford 1.8 Duratec engine.  I hope that this helps others!!