34 replies to this topic

[vvillium3]

hello all,

what kind of cc design do you thing f1 uses??? The typical pent shape??? I know they don't like sharing pictures about this kind of stuff. Just wondering if anyone has any pictures of older motors???
Also what do you guys all think about a slightly different cc like a ducati chamber(http://www.epicycle....es/ChamberT.JPG) with more side bludge than say most other designs??? What are the advantages to this kind of design as opposed to a typical honda cc????
Just wondering,
Jason

[rhm]

The only recent engines I've seen internal photographs of are the Asiatech and the Ferrari F2000's engine (I forget the codename for it).

All the Asiatech engines and parts were auctioned when they pulled out of F1 and now the engines are available on the open market from a variety of independent engine builders. Race Engine Technology did an article on in with many photos. It was unique among recent engines in that it didn't use finger-followers, instead having the camshaft lobes acting directly on the tappets as per a production engine. Not only is this inefficient at the kind of speeds these engines were running at, but it also posed problems because the valve were inclined in both axes - so the camshaft lobe had a 3d profile and was exposed to lateral forces.

Anyway, getting down the combustion chamber, they are not a strict pentroof design because as I said, the valves are inclined sideways as well as away from the centreline. This is purely to allow greater valve area. The pistons have large pockets to accomodate the valves and an 'intruder' in the centre to allow for the high compression ratios used. Appart from the valve angles though, it's not a million miles away from the combustion chamber design of any racing engine.

The Ferrari engine was also detailed in a RET article as an excerpt from the Peter Wright book about the F2000. Their combustion chamber was similar to the Asiatech design. The Ferrari used finger-followers though.

[vvillium3]

I have seen the photos of the the ferrari piston before, so I know what you are talking about....
I am going to look around for some pictures of the Asiatech design. Do you have any pictures or any links to the articles you speek of????
Also do you have any ideas what the buldge on the side of the ducati cc is for??? Better mixture delivery??? Higher compression????

thanks,
Jason

[desmo]

http://members.atlas...iatech2001.html

Here's the Asiatech pics, you can see a good bit of the CC in one of them. It's pretty much a dead conventional pentroof and lacks Ferrari's central intruder that effectively bisects their CC. Looks a lot like a Suzuki motorcycle CC in fact to me.

[vvillium3]

desmo,

thanks for the pics.

I wonder what the advantage of that side buldge is in the Asiatech cc is. Most likely for higher compression... Or possilbly to throw the mixture more towards the center of the cylinder rather than around the exhaust valves...
One thing that stuck out to me though, is did you notice the exhaust valve seat???? The actual seat is non-exsistent towards the center of the cc, then gradually becomes a full seat towards the outsides.. Very insteresting???
I love the pictures, if you have them please keep them coming....
Also is this Race Engine Technology magazine worth the subcription??? I am very interest into modifying motors. Like right now, I am in the middle of replacing the valve seat in a 95 bmw m3 head. While I am in there I am upgrading cams, going to solid lifters, and port+polish.... So I was wondering if this magazine has enough technical info in it????
thanks,
Jason

[vvillium3]

also, does anyone out there know of any really good book on combustion chamber design???? Anything from really scientific to theoretical to lamans terms is good. I just want to get my hands on something that will teach me the ins and outs....

thanks,
jason

[TestaRoasta]

Try SAE paper 700122. Honda describes the combustion effeciency of pentroof, hemi, bathtub, flathead, and wedge type chambers. It is a technical bit of reading.

[Greg Locock]

From the good old days when SAE papers included useful data. Neat paper.

[zac510]

vvilium, did you see the squish thread we had a few weeks ago?

[vvillium3]

no I did not... what is the title of it?????
thats for the suggestion about the sae paper. Is sae.org the best place to get those papers, or are there seperate vendors that sell them for cheaper????

thanks,
Jason

[zac510]

It is on the second page and is called 'squish on turbo' or something like that!

[J. Edlund]

BMW F1 head. Engine is unknown but it probably from one of their earlier engines.

[desmo]

Originally posted by zac510
It is on the second page and is called 'squish on turbo' or something like that!

http://forums.autosp...&threadid=83818

J. Edlund, thanks for posting that. I've got a photo of I think the 2001 or 2002 head and that looks really similar. I've got quite a few good F1 engine pics from over the years but some were given to me with the proviso I promise not to share them and now I have trouble remembering which ones, so I hesitate to post them unless I'm sure of the source.

[vvillium3]

J. Edlund,

thanks for posting that too. That is awsome.
I read that squish thread. Still have some questions though??? Should there be any relation of exhaust squish compared to the intake squish??? Somewhere I read that it could be better to push the mixture towards the exhaust side by having a larger squish on the intake side..
Do any you think any of these designs are any useful in a street/track car motor??? Oviously these design are for high revving, overly square motors. I just don't know if they are useful to us home tweekers or not....

this stuff if great!!!!

thanks,
Jason

[TestaRoasta]

OH MAN!! What show was that and when was it on Discovery?!

[Halfwitt]

Toyota head (bad picture, year unknown):

[vvillium3]

from a distance, looks pretty much like the bmw...

[zac510]

That Toyota head doesn't have the coolant gallery or as many head bolts (I think) so in some ways it is quite different.

Either way, both heads don't have the intricate troughs and peaks that the piston crown - it's hard to believe they go together!

[vvillium3]

i was talking about just the cc design.... All in all, it seems they all are fairly similar designs...

[J. Edlund]

Originally posted by vvillium3
J. Edlund,

thanks for posting that too. That is awsome.
I read that squish thread. Still have some questions though??? Should there be any relation of exhaust squish compared to the intake squish??? Somewhere I read that it could be better to push the mixture towards the exhaust side by having a larger squish on the intake side..
Do any you think any of these designs are any useful in a street/track car motor??? Oviously these design are for high revving, overly square motors. I just don't know if they are useful to us home tweekers or not....

this stuff if great!!!!

thanks,
Jason

How squish should be used depends on the engine in question. If the particular engine has the motion of the gas desired little good will come out of the use of squish. In fact, there may be negative effects such as sharp corners what result in hotspots, disturb the flame during the combustion or limit the flow around valves. On the other side if the engine suffer from poor gas motion the use of squish will result in increased turbulence.

The advantage of using a slanted squish is that it would be possible to increase the size of the squish area while also reduce sharp corners and other objects that for example may have a negative effect for flow around valves.

[vvillium3]

J. Edlund,

So would you say that the bmw head pictured above is on the verge of having to sharp of corners???? And also, at what point can a conclusion be made that the trade off between squish and deshrouding the valves is made???? Obviously again, the bmw head compared to a high performance street motor is quite a bit less shrouded around the valves. Maybe they are trading off higher compression instead of higher are flow....
Finally, does anyone have anyone have pictures of a 4 valve design on high performance motor like a 575m, or even that of like the maclaren f1???? Be nice to be able to see the difference between a top notch street motor and an f1 motor's cc....

thanks,
Jason

[McGuire]

Here are a few...

Ford GT modular V8


Plain old Toyota Corolla


Four cylinder Honda


Suzuki 750 Gixxer

[J. Edlund]

Originally posted by vvillium3
J. Edlund,

So would you say that the bmw head pictured above is on the verge of having to sharp of corners???? And also, at what point can a conclusion be made that the trade off between squish and deshrouding the valves is made???? Obviously again, the bmw head compared to a high performance street motor is quite a bit less shrouded around the valves. Maybe they are trading off higher compression instead of higher are flow....
Finally, does anyone have anyone have pictures of a 4 valve design on high performance motor like a 575m, or even that of like the maclaren f1???? Be nice to be able to see the difference between a top notch street motor and an f1 motor's cc....

thanks,
Jason

On the BMW head the corners are probably much less "sharp" than what can be found on for example production engines.

BMW's heads found in high performance applications also don't look that much different. Compared to the F1 head the F1 head seems to use larger intake ports in comparison to the exhaust ports. The exhaust valves also seems to be placed closer to eachother. The spark plug on the F1 head also protrude more into the chamber and the angles of the walls around the valves seems to be a little better.

[zac510]

J Edlund, do you think that BMW F1 head would have used a surface discharge spark plug or a 'regular' electrode spark plug?

M5 V10:

[vvillium3]

zac510,

how did you get that pic??? Truly awesome!!!

[zac510]

I remembered seeing it a while ago when the M5 was released!

[J. Edlund]

Originally posted by zac510
J Edlund, do you think that BMW F1 head would have used a surface discharge spark plug or a 'regular' electrode spark plug?

They use a small (8-10 mm base diameter) surface gap plug. Regular J gap plugs haven't been used on quite some time since their electrodes would break off in a F1 engine.

[McGuire]

Originally posted by J. Edlund


They use a small (8-10 mm base diameter) surface gap plug. Regular J gap plugs haven't been used on quite some time since their electrodes would break off in a F1 engine.

Exactly. Also, a conventional plug with extended nose and side electrode uses too much combustion chamber volume.

The current 8mm plug is tiny -- 40mm long overall with a stub for a spark tower and a 13mm wrenching hex. There are now 7mm plugs available for twin-plug applications.

[hydra]

Just out of curiousity, and since I know very little about the subject, why would one use/design for conventional spark plugs instead of surface discharge plugs? Also why not make the spark plug as small as possible? Is it due to thermal/durability concerns?

[vvillium3]

also, where is the optimum place to place the spark plug??? Dead center, in the middle of the cc??? Or biased towards to exhaust side???

[McGuire]

Originally posted by hydra
Just out of curiousity, and since I know very little about the subject, why would one use/design for conventional spark plugs instead of surface discharge plugs? Also why not make the spark plug as small as possible? Is it due to thermal/durability concerns?

I probably don't understand what you are asking... in an F1 engine you certainly do want the smallest possible spark plug (to maximize valve diameter if nothing else) and the least intrusion into the combustion space too.

But for other applications the limitations of service life and serviceability, durability and cost come into play... For one thing the tiny plugs cost around $50 each, which would certainly come down in high volume production though they would never be cheap.

...of course, one well-known problem with surface-gap plugs in road engines: it takes very little oil, fuel, carbon etc. to foul them with bridge deposits, while the extended nose and J-gap design is "self-cleaning."

[hydra]

McGuire,
My question was, since surface-gap plugs are seemingly superior to conventional plugs, why not use them in road engines, but you've already answered my question - thanks!

Another question is, why use the smallest (conventional) plugs one can find, e.g. 10mm instead of 14mm as I can see how that be advantageous for packaging and maximizing compression ratio...

[Greg Locock]

You don't use small plugs, generally, because they have to last 100000 miles in California, and no one will machine a head just for one market, and small plugs are less robust.

[Powersteer]

The Ford GT modular V8 combustion chamber McGuire shown looks patently similar to Suzuki's old twin swirl combustion chamber (famously imprinted as TSCC) four valve per cylinder design.

[desmo]

To my eyes, as I noted earlier, the Asiatech/Peugeot F1 CC looks even more like the old TSCC design.