Billet cylinder head

nice to see you back at work Dr-C , best pistons ever are whitout any doubs Mahle , Ktm use them on the 690 , it's an 102 mm bore , I fit the RC8R piston on some engines , very good results to , very stong piston but not to be used over 80 mm stroke , if you can , the best choice will be an Box-N-Box piston custom made by Mahle , they do so at Mahle Motorsport in US :wink: , i'ts my choice from 2 years now and I am very happy :cheers:

fdracing said:

nice to see you back at work Dr-C , best pistons ever are whitout any doubs Mahle , Ktm use them on the 690 , it's an 102 mm bore , I fit the RC8R piston on some engines , very good results to , very stong piston but not to be used over 80 mm stroke , if you can , the best choice will be an Box-N-Box piston custom made by Mahle , they do so at Mahle Motorsport in US :wink: , i'ts my choice from 2 years now and I am very happy :cheers:

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Thanks! The Mahle have a good reputation. I didn't know they did custom designs! I wrote them a mail directly! Have you ever tried http://www.wahlspezialkolben.de/? They are said to use Mahle forgings for their special designs.

Taffy said:

I do a 35mm pin and it is from Alphas so you can gaurantee the quality!

boring them out is so ify Mats....102mm is all I've heard of being completely reliable although I gather head gaskets have a fair bit to do with it?

Taffy

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Yeah, the head gaskets will be a challenge. Did the JBS gaskets work?

Off-topic. My first shot at producing anything with carbon and epoxy! Fun to practise!
This is a box covering the MSIII EFI, shielding it from water spray.

I am thinking of using a Phuzion Gas filled O-ring, and
the standard gasket with the fire ring removed and bore
( of gasket ) opened out to suite the ring.
Not sure if it will work. For my 103.65 bore kit JBS
whenI get around to it

http://www.cometic.com/files/CometicPhuzion.pdf

spanner said:

I am thinking of using a Phuzion Gas filled O-ring, and
the standard gasket with the fire ring removed and bore
( of gasket ) opened out to suite the ring.
Not sure if it will work. For my 103.65 bore kit JBS
whenI get around to it

http://www.cometic.com/files/CometicPhuzion.pdf

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I suppose it is crucial to get a proper tightening of the o-ring. That is automatically sorted with the intended head gasket (steel layers). Do you know to what distance the o-ring is supposed to be compressed? A OEM gasket is compressed to appr. 1,40-1,35mm if I remember correctly.

Does the liner work OK in terms of wear, water sealing etc?

from the pdf.

Phuzion Requirements:
Head and Deck surfaces should be within
.002” of flatness and have a surface finish of
50RA or finer. The compressed operating
thickness of Phuzion is .051”.

.051= 1.3mm

1.3mm looks close to the used OME gasket I have here
I wiil have to measure with a micrometer as I only have a verneer at home here.

Have not used the liner yet I wont to get it nicasil coated before I use it

The o-rings are about $50 each.
Maybe you could let me know if it works :lol:

spanner said:

from the pdf.

Phuzion Requirements:
Head and Deck surfaces should be within
.002” of flatness and have a surface finish of
50RA or finer. The compressed operating
thickness of Phuzion is .051”.

.051= 1.3mm

1.3mm looks close to the used OME gasket I have here
I wiil have to measure with a micrometer as I only have a verneer at home here.

Have not used the liner yet I wont to get it nicasil coated before I use it

The o-rings are about $50 each.
Maybe you could let me know if it works :lol:

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Ah, missed the info in the pdf! Hm... Maybe if having a well used gasket, you might get down to 1,30 mm. If the o-ring is possible to re-use, then the price is nothing! I need new gasket after every race weekend, among other things... :roll: Well, if it works with my 14,5:1 compression ratio, then you might dare to have a go?

I have not seen anywhere that says the O-ring can be reused
so I doubt that it can.

I only thing that worries me is that there is no steel centre
in the OME gasket to back up the Oring. It might be possible
to turn a steel ring for this purpose.

If it works for your 14.5:1 compression I would give it a go for sure 8O
What fuel do you run?

What size bore are you thinking of?

You may not have to change the head gasket after each weekend either

Are you using stronger than standard or fine threaded head studs?

I'm using Shell V-Power from the tap. It used to be 100 octane, but I think it is less now. No detonation so far. There is very little obstructing the flame front in my combustion chamber, so I guess that helps.

I do not want to have larger bore than what can be fitted in the crank case without taking any material away. I guess 104 mm with a steel liner is max. Mahle in US are doing custom designs (min 4 pieces).

I'm thinking of a copper gasket with a steel wire on top of the liner... Not sure if it will keep the water in place though...

I pressed together a 35 mm crank today, so thats sorted at least.

in term of head gasket I solve the problem, ( because it was a very big one !!!! ) , using an Viton o-ring as pressure gasket and loctite 5923 ,so the head is directly on the cylinder , it work pretty well , no leaks at all ,even at peak torque.
I change the o-ring every 20 hours to be sure , but it looks always in good shape with some small scraps

never tryed metal o-ring , some says there are good for small bore , less than 100 mm and cant be re-used :?

fdracing said:

the head is directly on the cylinder

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That would be a very nice solution! I fear the cam chain will get too long (from reducing the c-c between cam and water pump shaft) and get in contact with the water channel in the cam chain tunnel. You had no problem with that? I got that problem already after decking an OEM cylinder head, with a new chain...

Did you machine the o-ring groove in the edge of the liner?

I've CAD:ed the sleeve and asked for pricing on a 115mm dia rod of 2541-mtrl.. I'm prepared to get chocked.

I made the groove in the head



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on the pics you can see what's going on when a stud broke :? , it happens on 6 gear at 210 km/h

regarding the cam chain , I put two chain tensioner rail and two cam adjuster one in the stock place and the other one in the front , so I can adjust my timing easily :wink:

depending on suppliers , my viton o-ring doesnt last that much :? , the last one 5 hours !!!

so , i am gonna try those famous metal o-ring , it seems to be hard to find them out available ? the Cometic Phuzions aren't in my diameter ,in US they use some others , on drag engine and tractorpulling , i will receive some samples next week , i let you known :wink:

big power is nice , keep it in the cylinder is better :cuss:

I have found a Czech company "Merako" that are producing all kinds of head gaskets, traditional design and from sheet metal (Zn or Cu-plated, 2-3 sheets). They are doing gaskets for fx Cosworth, WRC-applications and Jawa speedway bikes. I will send them a dxf-file and let them do a test. The pricing is very reasonable.

at the end of the day i decide to do the metal-ring myself , it's an square ring with 2 teeth on both side i made it on stainless steel 431 , oil pressure has it's own o-ring , and for water sealing i use an simple paper gasket.

it may give you some idea for your engine :wink:

i start the test yesterday , it seems to work well for the moment :wink:

today , hard ride , and let see what's happen !!!!

so !!! , the ring do the job !!! full throttle on 6 gear for miles , the only way i know for testing !!!! :wink:

Mats

I've just read possibly the best book ever about racing and engines. it's by Kevin Cameron and named "classic motorcycle racing engines". the write ups on amazon are 5/5 stars all the way. he gives away loads of info on tuning.

two things struck me: the first is that in order to make cranks that could cope manufacturers are all running one piece forged cranks with split rods. that would mean a high pressure oil pump.

the second thing that repeatedly came through was how oil is used everywhere to cool the engines without having to resort to larger coolant radiators or indeed oil coolers. oil is sprayed EVERYWHERE!!! this allows higher compression ratios.

I have drilled the ledge on the left as you look down and fitted not one but two oil squirt jets to an FC470 with good results. it is a blessing that the oil feed is there!

oil evacuation and crankcase pumping pressure was drawn in with recent Jap engines evacuating the cases of pressure using reeds and also flowing the routes that the air would take. gas flowed crankcases!

another thing that I studied in great depth back in the nineties was the aspect ratio of the rods. at the time everyone was pushing for 1.75 to 1 AR but it now appears to have settled at 2.1 to 1. on your 82mm stroke this would be 172mm and you're on 134mm. that is quite a difference. 38mm!

would it be best to consider a 550 plain bearing crank allowing a further 5mm around the periphery of the con rod for bolt heads? I have experience already of machining cases to avoid long stroke rods scrapping everywhere.

I suppose you'd be in car country here....

another thing that came out of the book was that roller big ends went down to 3mm rollers 50 years ago due to inertia and skidding - even when caged. to go to 3mm rollers would allow a 34mm big end pin.

so a 550 crank with a 34mm big end pin with 3mm rollers and a 140mm C to C rod....there's one out there already from Honda.

I still believe you have a whole host of stuff looking to fail due to the massive increase in BHP that you've found. not happy to say it but I think there is a minefield of stuff ready to pack up. when they used to race TZs etc everything had a service life, so many hours etc. I'm sure you've thought about this.

I can't recommend the book enough. one of the best books I have and will ever read. http://www.amazon.co.uk/Classic-Motorcycle-Race-Engines-Technical/dp/1844259943

regards

Taffy

Thanks for the tip on the book, Taffy!
Sounds like a "need to have". I will most certainly get one.
The modern 1-cylinder 4-stroke racing engine we will find today, is in my opinion represented by the Moto3. Another good source to steal ideas from, when getting closer my "1-cylinder volume", are the Ducatis. I have not studied either of them in detail, but from what I can tell, both designs are challenging what we thought was the correct way to go. Both when it comes to rod length, max bore and crank design.

I know that with the power I'm getting, there is no such thing as reliability. I have installed a 80 mm stroke crank for the season, to make the spherical ball mains, last a whole weekend. I dropped the 104 mm bore, because I had to wait 3 months for the Mahle custom pistons. I have managed two training events up til now, this year. So the engine has endured 2 hours of operation already! The tougher valve springs, seem to have the valves under control. With the 14,5:1 compression ratio, crank case ventilation seems to be a problem. The transmission cover gasket, does not want to stay in place... The OEM head gasket works fine, as long as I do not reuse it. But, hey! I keep up with 600 Supersportbikes on the straights! :twisted:

I'm now running LiPo-batteries instead of generator. The voltage is free from noise now, which makes EFI and Lambda sensor work just fine! The MS3 EFI has a log feature, so I do not need a dyno to adjust the fuel map any longer.

The coming weekend we're off to Finland for the first races this season. It has been a while, so I guess the parameter setting the pace, is the blob on the seat!

The book will be my next bedtime reading. The last one was "Four strokes performance tuning".

Hey Mats great to hear you're having a red hot go ! I'm glad to hear that your changes are effective and I admire your perseverance and conviction! :cheers:

Thanks Bergismerg!
As I mentioned, the 14,5:1 compression ratio, results in a higher piston blow-by. The pressure in the engine goes up and the transmission cover gasket is occasionally, on the run. So, in order to relieve pressure more efficient from the crank case, I fabricated an additional vent. I'm not using starter motor or kick start shaft, so there was space enough for this solution:



There are some more stuff to fix the coming evenings/nights, before the first race 18-19th of May. Exciting!

you'll need sponge in the neck of that somewhere to stop the oil just walking straight out!

the book talks of the battle for small valve area in the head versus lots of breathing through lots of valve. this is why Yamaha dropped the 5 Valve head. they were able to get the same breathing through the 4-valve head. this allowed less lead on the ignition timing.

you have one tremendous advantage and that is that a single doesn't have the sheer speed problems.

I reckon a plain bearing 550 revving its tits off would be as quick as the 650 and a lot less stressful for it!

well, whatever, it is exciting. we had two Swedes over last week who hadn't heard of you Mats! we had to put it right!

regards

Taffy