Its all about the flow, you know. - MA series head porting

[Ed]

Check this out:

IMG_4249_resized.jpg

Above the standard port layout. Below a modified one. That should help a little I hope, infact get the head right and you stand to gain 20% bhp. What I can say is that under test the exhaust ports flow the same at 1mm less lift on the modified port as the other port did unmodified.

This would obviously work on any k10 too etc...

 

[Retepetsir]

Very nice indeed Ed. Was this a DIY modification or did someone else do it? Would something similar work on the CG13 engine?

 

[Craig]

Nice, but it's not all about flow, it's about mixture

ANy valvework being done?

 

[Ed]

Pete, I did it.

Craig, do some practical stuff and stop spouting theory lol. Its the heads job to carry fuel and air yes. BUT your wrong about mixture, or misleadingly inaccurate. Yes there will be extensive valve seat work done. There is much to gain in this area.

Ed

 

[Retepetsir]

Very nice, it takes skill to do such a thing properly and that looks pretty good to me .

If I'm going N/A (or even if I'm not) I'd be interested in some headwork on the SR.

 

[Ed]

Some heads are more beneficial than others. The k10 inlet ports are ok, the exhaust are terrible, with room for SIGNIFICANT improvement.

I don't have a great deal of experience with head work, but it took about 4-5 hours to do the exhaust ports. Now I need to do the inlet, get it skimmed then the chambers CNC machined and finally valve seats cut.

Ed

 

[Craig]

Pete, I did it.

Craig, do some practical stuff and stop spouting theory lol. Its the heads job to carry fuel and air yes. BUT your wrong about mixture, or misleadingly inaccurate. Yes there will be extensive valve seat work done. There is much to gain in this area.

Ed

Ah, I didn't see that these were theexhausts ports - top job then

I wouldn't say misleadingly inaccurate, just a bit ambiguouous (SP??).

What have you planned for the inlet, or is that classified?

 

[Ed]

The inlet just needs basic work done, to remove a few bumps and obstructions. Not a great deal really, nothing at all like the exhaust ones.

Its not secret as lets be honest, who is going to try and copy this lol?

It should go quite nicely with my new conrods, pistons and flywheel....

 

[richj]

Ed, will you need to adjust the timing to exploit the extra flow to full effect?

 

[Craig]

Interesting, so you will be keeping the inlet side pretty standard - have you any thoughts (or even loked at) a K11 head?

Quiet nicely? Not with your exhaust! Any ETA on it being back on the road?

 

[Ed]

richj. You mean Cam timing? If so thats a tricky one as I would need a vernier pully for a K10, and thats going to be easy - not! If ignition timing then yes, natrually, the car will need a significant remap after all this anyway.

Craig, typo - corrected. ETA two months. Conrods take 6 weeks. Thats really the delay.

 

[richj]

Yes i meant the ignition timing. Just trying to make sure my understanding is sound. With the better flow you would want to advance the ignition slightly? The cam timing is interesting. Would you advance the cam timing too?

 

[Craig]

richj. You mean Cam timing? If so thats a tricky one as I would need a vernier pully for a K10, and thats going to be easy - not! If ignition timing then yes, natrually, the car will need a significant remap after all this anyway.

Craig, typo - corrected. ETA two months. Conrods take 6 weeks. Thats really the delay.

Very nice

 

[Ed]

richj, it depends. There are many factors to it. If the problem is the exhaust cannot escape fast enough then with that part of the system being freer you could I suspect run more ignition simply as things would run cooler. However the opposite could also be true if it allows in more fuel air mixture and thus produce more power added to the fact less back pressure and then you may have to run less advance.

Cam timing is tricky, since its not possible to alter intake and exhaust independently as its on the same cam. I would imagine a couple of degrees advance would produce some results here.

Just to add too, I have a direct port nitrous upgrade kit to go on as well.

 

[richj]

A couple of degrees of advance would produce some results because you could achieve the same inlet efficiency, but increase the exhaust flow?

 

[Ed]

I want an overall improvment. This will make a lot of power.

 

[Craig]

Cam timing is tricky, since its not possible to alter intake and exhaust independently as its on the same cam.

You need to do a 16v head conversion

 

[Ed]

No, I dont.

 

[Baz]

Ed depending on the results I may consider going down this route,shame to rip mine apart again though

 

[whipit]

Its not secret as lets be honest, who is going to try and copy this lol?

Only i would although it wasn't as extensive as yours i did spend 7 hours on the exhaust ports and 2 hours on the inlet being the first head i've ever done. Valve seats have also been cut.
Whats chambers CNC machined?
Whats the specs on this new flywheel?

Also just something i was told by the engine engineer at work, the inlet port on a car with carburettor is a core part the atomisation of the fuel. Therefore you don't want it polished.
Although your injection just didn't want any ma10/12 owners getting the wrong idea if this is correct??

 

[Ed]

It souldnt be a mirror polish true - but a rough finish in say 60 grit is fine. Its the same for inj and carbs. The point being you dont want fuel to condensate on the walls of the head. Which btw is only really a problem and low rpms etc..

 

[whipit]

Yeah thats about right for how it was, hence inlets took only 2 hours. lol
Looking forward to seeing the results, already said i will join Olly next time he pops over!