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998 head work
https://www.ausmini.com/forums/viewtopic.php?f=5&t=66651		 Page 1 of 2
Author:  tuff998 [ Sun Oct 31, 2010 9:43 pm ]
Post subject:  998 head work
Ok i have a standard 998 afaik lol. I want to get it converted to unleaded so I dont have to put the additive in all the time. Now while the head is off, would I see a decent improvement in power/torque if I get it port n polished? (even with the standard low compression)

It also has full exhaust system and atm has the 1-1/2 SU but a 42doce awaiting a small manifold to go on.

Im thinking about rhemacs for the work but does anyone know of what the cost could be??
Author:  Phat Kat [ Sun Oct 31, 2010 9:59 pm ]
Post subject:  Re: 998 head work
tuff998 wrote:
Ok i have a standard 998 afaik lol. I want to get it converted to unleaded so I dont have to put the additive in all the time. Now while the head is off, would I see a decent improvement in power/torque if I get it port n polished? (even with the standard low compression)

It also has full exhaust system and atm has the 1-1/2 SU but a 42doce awaiting a small manifold to go on.

Im thinking about rhemacs for the work but does anyone know of what the cost could be??


Hi mate :)

Depending on what you get done, head work willl cost you from around $600 up. If you just want the head reco'd then about $200-$300 is fair.

Edit> and yes, you will see an improvement from getting mild head work done even with a standard cam. Small bore heads are the most astmatic in the A series family. Just going to bigger valves and deshrouding the chambers will give you a pretty good improvement on a standard motor. If you're going to a warmer cam, then certainly look at getting the ports done too.....

But what casting do you have? Do you know which 998 head it is?
Author:  tuff998 [ Sun Oct 31, 2010 10:03 pm ]
Post subject: 
cheers mate.
yea I was expecting around the 250 mark. ill have to ask for a quote for the porting. I may even be able to get a discount as my boss uses Rhemacs for our customer jobs and for his own tarmac rally mustang :P
Author:  Phat Kat [ Sun Oct 31, 2010 10:07 pm ]
Post subject: 
haha, can't hurt right? :P


Do you know which casting you have though? There are a few different small bore heads, some are better than others... if you're just running a standard cam, you might find that there is little improvement to be made if you have a head like a 12G295...
Author:  tuff998 [ Sun Oct 31, 2010 10:13 pm ]
Post subject: 
Nah i dont know which one. its on the top of head right? you need to remove the rocker cover yes?

just the standard cam is used although I want to work the engine a bit in the future.
Author:  Phat Kat [ Sun Oct 31, 2010 10:20 pm ]
Post subject: 
Yeah the number is under the rocker cover.. its towards the back of the head (the manifold side).... It will be something like "12G***" .
Author:  GT mowog [ Mon Nov 01, 2010 6:51 am ]
Post subject: 
While you've got the head off, have it skimmed to raise the Compression Ratio, it will give a good improvement.
Author:  Super-mini [ Mon Nov 01, 2010 10:28 am ]
Post subject: 
since you're up that way
I recommend taking the car to dave armstrong motors, jason armstrong really knows his stuff, especially with minis which he races in historic touring cars.

probably cheaper than rhemac even with a discount :lol:

deshrouding the combustion chambers i think are more important than the ports but anyway see how ya go.

7 Acrylon Rd, Salisbury South SA 5106, Australia
8258 1509

otherwise you can get a bottle of flashlube that hooks up to your carby vacuum line and meters it out in minute quantity. Can get them new from supercrap.

in the long run you're better off with hardened seats, especially if you have the cash to modify the head.
Author:  tuff998 [ Mon Nov 01, 2010 5:16 pm ]
Post subject: 
Super-mini wrote:
since you're up that way
I recommend taking the car to dave armstrong motors, jason armstrong really knows his stuff, especially with minis which he races in historic touring cars.

probably cheaper than rhemac even with a discount :lol:

deshrouding the combustion chambers i think are more important than the ports but anyway see how ya go.

7 Acrylon Rd, Salisbury South SA 5106, Australia
8258 1509

otherwise you can get a bottle of flashlube that hooks up to your carby vacuum line and meters it out in minute quantity. Can get them new from supercrap.

in the long run you're better off with hardened seats, especially if you have the cash to modify the head.


Ahk may do. would it be better to leave the car with him or just the head?
Author:  CPOCSM [ Mon Nov 01, 2010 6:21 pm ]
Post subject: 
Go a 12g202 and get rid of the beaks in the chamber. Flows 100 percent better and is good for when you force induce it.

Image

Hooroo
Author:  mattsmadmini [ Mon Nov 01, 2010 9:54 pm ]
Post subject: 
Image

Yummy.... a 12g202 that has been slightly worked... de-shrouded and ported, makes for a nice bit of power, at the moment though is in pieces and in need of a skim (max skim from a stock 202' is around 60 thou, over that and metal starts getting a little thin between all the water holes)

i do love looking at it though... :lol:
Author:  david rosenthal [ Mon Nov 01, 2010 11:38 pm ]
Post subject: 
you can also try Harman Engineering at sailsbury. He does the seat inserts and at a good price. I get him to do all my re-bores and crank grinds . For the VRS set try auto-pro in gawler [ask for Darren] as he knows minis well and cheapest price around for a quality gasket set made in USA with a steel / compound head gasket.
Author:  tuff998 [ Tue Nov 02, 2010 12:26 am ]
Post subject: 
12g202.. is that the 1275 head or one of the various types fitted to the 998s?

ok so the to-do list would be
-hardened seats
-de-shrounding
-porting if affordable
-12g202 head to be used if avaliable :P
Author:  Tadhg [ Tue Nov 02, 2010 1:01 am ]
Post subject: 
12G202's a small bore head. I think they started on the 997 Cooper, common on later motors (1098, etc), second least shrouded chambers of the small bore heads (if my memory serves correctly!). They're not too uncommon, so they don't go for big money like a 12G295 (998 Cooper, MG1100 (again, I could be wrong!)) head, which is much rarer and flows better, though a well worked 202 can be better than a 295. And stock, a 202 flows better than the early 850 heads. Which means you spend less money machining them, because you remove less metal.

A 1275 head would be nice, but then you'd likely also be looking at notching the block.
Author:  smac [ Tue Nov 02, 2010 5:00 am ]
Post subject: 
I have a 12G295 sitting here to get checked one day.....but it looks like it was left outside and is likely stuffed. Valve guides looked to be rusted to the casting....bum....
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