combustion chamber mods
combustion chamber mods
Author
Discussion

a1rak

Original Poster:

556 posts

212 months

Thursday 21st October 2010
quotequote all
Have got my engine apart and as i mentioned in earlier threads would like to improve on things where possible.
I was loking at the combustion chamber and both the inlet and exhaust valves are very close to the chamber wall. There is a couple of millimetrs before the compression ring on the gasket is reached.
I was thinking of releaving the combustion chamber wall at the points circled in red to assist flow.
What do you think? worth doing or not?


[url]|http://thumbsnap.com/iaL27ZJM
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itiejim

1,822 posts

234 months

Thursday 21st October 2010
quotequote all
Unshrouding that valve would almost certainly help - but you really need to know what you're doing. You'd want to cc the chambers and ensure that the head is skimmed to keep a sensible CR.

Personally I would't be happy mucking around with an AJP head as there are so few around - how brave are you feeling?laugh

Alternatively take the heads to someone who really knows what they're doing.

a1rak

Original Poster:

556 posts

212 months

Thursday 21st October 2010
quotequote all
itiejim said:
Alternatively take the heads to someone who really knows what they're doing.
Can you recommend anyone, prefereably someone who charges sensible money, the last quote I got was £1200.00 +vat.

HarryW

16,028 posts

298 months

Thursday 21st October 2010
quotequote all
a1rak said:
itiejim said:
Alternatively take the heads to someone who really knows what they're doing.
Can you recommend anyone, prefereably someone who charges sensible money, the last quote I got was £1200.00 +vat.
Don't know how much he charges but David Martin at Austec has in excess of 40 years experience in this, including the straight 6 and V8 lumps for AM specials. I've known him to ring David Vizard at a drop of a hat if necessary. He's built up quite a workshop there too, with all the in house machining and flow benches needed and over the last few years has really done a lot of testing and dare I say it experimenting with AJP8 heads, including bench testing the whole engine. I surmise a lot of the experimenting was actually done with my lump tbh hehe, it now has torque you wouldn't think possible from a 4.5 AJP8, north of 400lbs.
Worth an enquiry, although I suspect the figure quoted above may already be from him hehe.

Gazzab

21,640 posts

311 months

Thursday 21st October 2010
quotequote all
Had my heads reworked incl porting and matching etc plus a remap to sort fuelling and ensured we got the cr right. Wasn't cheap as it's man hours but hrly rate reasonable. Now got one of the most powerful cerbs there is. Could easily get more power if we turned up the wick but nearly 440 is enough for now....?!

itiejim

1,822 posts

234 months

Thursday 21st October 2010
quotequote all
I'd speak to someone local with a reputation in motorsport. Austec certainly seem to have a good reputation and Paul helped me out with a few things when I rebuilt my AJP.

a1rak said:
itiejim said:
Alternatively take the heads to someone who really knows what they're doing.
Can you recommend anyone, prefereably someone who charges sensible money, the last quote I got was £1200.00 +vat.

a1rak

Original Poster:

556 posts

212 months

Friday 22nd October 2010
quotequote all
Gazzab said:
Had my heads reworked incl porting and matching etc plus a remap to sort fuelling and ensured we got the cr right. Wasn't cheap as it's man hours but hrly rate reasonable. Now got one of the most powerful cerbs there is. Could easily get more power if we turned up the wick but nearly 440 is enough for now....?!
Couple of questions if you don't mind.

Who done the head work that you mention?

What else was changed

1. Factory Standard Pistons?
2. Factory standard cams?
3. Factory exhaust manifold?

DuncanM

7,461 posts

308 months

Friday 22nd October 2010
quotequote all
Hello,

I've just emailed you some info that you might be interested in.

Regards

Duncan

Gazzab

21,640 posts

311 months

Friday 22nd October 2010
quotequote all
a1rak said:
Gazzab said:
Had my heads reworked incl porting and matching etc plus a remap to sort fuelling and ensured we got the cr right. Wasn't cheap as it's man hours but hrly rate reasonable. Now got one of the most powerful cerbs there is. Could easily get more power if we turned up the wick but nearly 440 is enough for now....?!
Couple of questions if you don't mind.

Who done the head work that you mention?

What else was changed

1. Factory Standard Pistons?
2. Factory standard cams?
3. Factory exhaust manifold?
Raceproved did the work - Joolz and Russ.
Standard pistons, cams and exhaust manifolg. There is little to be gained (if anything) with changing the manifolds unless you hack out bodywork. AFAIK