Cam timing

I tend to disagree.
English air is colder because it is further from the equater, so being colder it is also denser.

[Alpineandy]

but you won't get your ports near 46mm, maybe 42mm max,

What are the standard?

I was showing Stephen Dell the other day, the plastic intake pipe that diverts hot air into the air filter chamber on a GTA atmo,....., proving even a simple restriction removed on an standard engine makes a difference.

A310s into the airfilter are very restrictive, I guess the A310grp4 mod of having a second pipe into the airfilter would seem like a comparative 'value for money' improvement then.

it would be possible to convert a complete Z7X engine to oddfire if you wished, and still be cheaper than modifying your heads.

.

Not without getting creative with the gudgeon pins. Odd fire engines have the pins press fitted to the rods, the even fires are all fully floating, and a different diameter

Andy
Heads were done by 'the best man in the buisness'.

Gas flowing is not expensive, swirl flowing is though total for the two heads was about 1.5k for all the work I had done.

Comes out like this:
Swirl flowing ins and outs- 550
Nucleus valve guides -400
Valve seat reprofile- 200
Cumbustion chamber mod- 100
Blah blah blah, say- 200
+you have to account for new valves and springs etc

In the thread polishing of ports is mentioned, that is a practice of the past, and is counter productive, ports should be 'lightly' rough this prevents fuel dropping from the atomisation as it passes through the port.

You also need to consider the whole picture, right from where the air comes in to where the exhaust gas leaves, a single restriction can undo all your good, as can a 'cave' (cave's will stall the fuel/gas flow as much as a restriction does) i.e take the talbot inlet manifolds, look good on the surface, but watch them work on a flow meter, horrible, but with a little work 'great'.

Mind you I am now, but only the dyno will prove the work I am doing then I may be

Cam timing complete 108.5 on both.

Some hints though, always wind engine forward, backing off (by even 180 degrees) and then coming forward again seems to give up to 1 degree deviation.

Thought came about though after turning engine over for the 100th time What happens to the cam timing when the engine gets hot and the chain expands,. See those french boys were clever, Variable Cam timing 10 years before them Japanese or maybe they were even cleverer than that, cam chain expands at same time as the engine bigger there goes the compression ratio.

and as the engine gets hot, so the cam gears will also expand reducing the variable effect you suspect.

Andy
Heads were done by 'the best man in the buisness'.

Gas flowing is not expensive, swirl flowing is though total for the two heads was about 1.5k for all the work I had done.

Comes out like this:
Swirl flowing ins and outs- 550
Nucleus valve guides -400
Valve seat reprofile- 200
Cumbustion chamber mod- 100
Blah blah blah, say- 200
+you have to account for new valves and springs etc

In the thread polishing of ports is mentioned, that is a practice of the past, and is counter productive, ports should be 'lightly' rough this prevents fuel dropping from the atomisation as it passes through the port.

You also need to consider the whole picture, right from where the air comes in to where the exhaust gas leaves, a single restriction can undo all your good, as can a 'cave' (cave's will stall the fuel/gas flow as much as a restriction does) i.e take the talbot inlet manifolds, look good on the surface, but watch them work on a flow meter, horrible, but with a little work 'great'.

Mind you I am now, but only the dyno will prove the work I am doing then I may be

Ooo... I must get myself some nucleus valve guides... I always knew I was missing out somewhere: lol:

Serious, what happened to this project were there any results?

Car is now used regularly at hill climb events, and performs well especially considering the car is still heavy, and the driver gets increasingly heaver!

Power at the flywheel for the 2664cc engine is now just under a fraction of 200bhp and 190ft lbs. Max power reached at about 6250rpm and with a useful 150ft lbs above 2600rpm.

Gearbox, remains a pain, never keen to be hastened especially on down changes , and the final ratio remains a little high (I have a 3.69 CP ratio) so always on the lookout for a gearbox with a CP of 4.11 So if you hear of one going do let me know.

Excellent thanks for the info, do you have any power / torque graphs you can post up? What sort of transmission loss figure were you getting?

So the cam is ground on the 112 deg LCA, but advanced 4 deg to 108 deg right? I take it this is the high lift Kent grind? Did you have any valve clearance issues; I assume you are on the 44mm inlet still? Sorry loads of questions, smile... can think of a few more Are you running mapped ignition on this setup?

Will have to dig out the graphs, away from home at moment but will try on return.

Cam's are Kevin specials so no idea on their spec bar they provide a high lift, and in my case as my CR is now 12.25/1 (we run fuel at 105+ octain) they did cause some major concerns on clearance and as whether the valves might start to kiss the pistons at high RPM (we run the engine red line at 7250), but touching wood nothing bad happened yet inspite of a tale-tale that regulary show that I exceeded the (now orange) red line with one slightly over exhuberent 7500rpm recorded!

The disty is as was, nothing trick.

Ohh one other thing, not mentioned in earlier thread, we had new choke tubes made for the 40it's up from the standard 31mm to 34mm which gave us 15bhp but increased the onset point of 'useful' torque