Beak or De-Beak
Turbo Mini Forums

Straight talking as ever Vegard! lol!

In the 13's at last!.. Just

Easy fella's... takes alot to translate Australian into English

Here is a post from another site (I posted it so its ok to copy it here)

What I am talking about is the seats.
If your head is DE-beaked (in a smallbore head) then you wont get wear on the seats. With a big bore head... the chambers are slightly more 'open' ie/ the beak is not as pointy but still wears if its not 'de-beaked'

So, one of the benefits of 'de-beaking' in both big bores and small bores is that you get less wear on the seats.


Original Post
Howdy,

Was at Graham Russells and badda bing badda boom the head from the LS came off.
Here are the pics of the seats.
FYI THEY ARE NOT HARDENED SEATS!!!!!

It was put on in 1995 and been running on Premium Unleaded.

No wear on the seats - and it has not been running any additive.
Also, it has done about 30,000kms since '95'

Judge for yourselves...






Cheers,
Peter.

Edited by pristic on 11th Jul, 2007.

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

hard to translate Australian to english?

Vegard is from Norway and he thinks your talking crap!

people on here can be a little blunt at times, dont take it to heart.

Edited by pristic on 11th Jul, 2007.

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

What Im saying about beak vs de-beak is that the more shrouded the chamber is the hotter the exhaust valves run. This is especially the case on stock small bore heads as they are like heart shaped with considerable amount of shrouding around the valves. Small bore heads all run considerably hotter than big bore because they do not get any cooling from the intake charge.

This is the real reason why exhaust valves last longer on big bores and modified chamber heads. Nothing to do with additives or not.

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

after looking at your pics i assume you can also state that De-beaking also prevents valve guide wear, rocker shaft wear and abviously radius arm wear.

i think a few more miles are required before bold statements, say another 100,000 miles

some one (federation of somthing or rather) did state once that not running any additive and standard unleaded would wear the valve seats but this would take many miles. also if the head has not been touched the build up of old lead/crap would protect the seats and help it to last even longer.

can you not type your replies at the same time as me, it makes for a confusing read.

Just contributing my bit with pics as proof.
If I got pics of 100,000 miles and they were identical would you say the same thing?

Dont have to believe me or take it on, its a beak vs de-beak thread and this is something we found...

And dont be a smart-a$$ ... you know radius arm wear is caused by the wrong air filter... not de-beaking.

Peter.

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

On 11th of Jul, 2007 at 12:50pm Turbo Shed said:
can you not type your replies at the same time as me, it makes for a confusing read.

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

mine has no beak and i had to change the valves from 32mm to 33mm to compensate.

could your good results be due to a lowered compression and thus lack of power? or your head could be made of a better material than normal?

surly it must be bed time for you about now?

hmm, is this claimed by Graham R. too?

This, of course, is no proof whatsoever.

Any test needs a control to prove a thoery. So you need an identical engine that has done identical running, the only differance being the 'beak'. Then the two can be compared.

I like the theory to some extent, but I wonder how much extra heat is involved. I'm also not convinced about how less shrouding significantly improves cooling of the exhaust valves (assuming all other factors are the same).

Interesting though.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Hmmm i slightly get pristics point on this one. Do you mean that the combustion is spread around more of the chamber rather than concentrated over the valves. Or am i being thick?

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

Yes interesting theory but is this pattern seen due the de-beaking or the other chamber mods done? I dont think anyone would de-beak without also removing material shrouding the valves. Many engine designs never had a beak in the first place, does that mean they never suffer valve recession? I dont think so.

Also valve recession is overrated anyway, It either happens or it does not, pot luck. Unleaded fuel dissapeared in the States many years before it did in the UK yet there are many unleaded cars still running around over here without inserts. My 1968 TR250 managed 10 years and at least 30,000Km on a freshly cut head without any recession.

Having said that I did have inserts installed on my Mini engine as a precaution.

website:- http://www.terryhunt.co.uk

mine has no beak and has suffered valve seat recession. but then mine is 1293 turbo

maybe with the 998 NA, the total lack of power may have reduced valve seat temperatures and thus reduced recession.

valve spring pressure can effect this , my original engine build in 98 did about 15 k miles and had 2 mm recession on the middle cylinders and about half a mill on the outers .that was on 9.3 to 1 and 4 psi 114 bhp .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Allright, I do understand the theory of you're statement now. However, if this is so, I guess valve material is very determinal as well. In real life, I don't really think that the exh valve is cooled by air intake at all. This will have so little effect as there's hot gases travelling by all the time. Of course, inlets last longer due to this, but the amount of degrees colder the exh valve will be because of no beak would be almost nothing at all. If you turn it around, the extra swirl by the beak would help fill the cylinders better= more cold air in the cylinder.

All theory, very hard to substantiate! I guess you agree.

Absolutely, its not 100% in any way shape of form. But its interesting yes. I have absolutely no way of testing this 'properly' so wont try... but have decided on my strong small bore not to have unleaded seats fitted and I am running unleaded without additives.

I reckon the chambers look better without a beak personally anywayz

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

Graham knows a great deal more than most of us about our engines (not turbo specifc though) so his theories should indeed be listened to...

He is the guy that have designed all Keith Calvers cams, the new pistons available from minispares and so on...

I do agree that this does not seem to be the only reason for valve seat wear....

Edited by miniminor63 on 12th Jul, 2007.

all the informations coming from k.... and g..... (canot be more precise if I doesn't want to be deleted)
with some care (alot of) and a pince of salt , the first have a lot of issues with his states of the art, never gave proof of, sometimes tell big BS (look for the year 3000 advance in technologie new astonishing unbelievable improved design of the very last highflow oil pumps, pure S...), in fact only a very good commercial.
the other certainly is knowledgeable , but all his data seem to be/have E.T bananas.

About the beak , it's here to prevent exhaust contamination by inlet charge, so it's theoricaly normal than the exhaust valve will be cooler if it see some fresh charge, but does I want these gas to go thru exhaust? it's more the job of a valve seat to prevent wearing (hardened one),
about Kc comb chamber it mimic some american v8 bath comb chamber, so have nothing with new.
at least it's easily doable to make a comb chamber large enough without these tweaks so why? (for ex 15cc piston, 4c in hg, 26cc in head =45cc , nothing more is needed) and this is with a good squish (pistons topped), and a conservative head, known (weslake) to be very effective .................
blabla bla bla

and they say I need to stop drinking

1132cc Turbo ~120 bananas ATW - Fun Fun Fun

On 12th of Jul, 2007 at 10:44am pristic said:
and they say I need to stop drinking

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will