Way back when, in 1997 when the Judd-Yamahas were supplied to the Arrows team driven by hill and diniz, it was publicized in the motorsport tech comics (racetech I think) that Judd were screwing the cylinder liner into the head casting, i’m told by only about 2.5 to 3 turns of thread on the upper rim of the liner only.
What this enabled the boys at Judd to do was drastically reduce the size of the head bolt fastners - and their position, that were required to clamp the head down, as they were only clamping down the combustion force……not both the combustion and sealing force - i think........which made for a nice compact, and lightweight head and block assembly............
This 97 judd engine spawned the F1 micro engine scene, weighing in at less than 100Kg
My question is …….does anyone know if any other F1 engine manufacturers are still screwing the liner into the head?.......or are they still using either beryllium copper crush rings or wills rings?........I would be interested to know what the preferred route now is being taken???......I know cosworth cast their liners as part of the block.
screw-in f1 engine cylinder liners???....
Started by
knighty
, Nov 03 2005 13:57
10 replies to this topic
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#2
scarbs
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Posted 03 November 2005 - 15:35
I believe (but stand to be corrected) teams use cast liners with coatings to reduce surface friction...
#3
desmo
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Posted 03 November 2005 - 19:22
From an article in Racetech #19:
"...the key to [the OX11A's] dimensions and weight was some radical architectuure in the form of screw-in liners, as now patented by Yamaha."
Judd: "The idea of building the engine that way came from us but I wouldn't personally regard it as any kind of invention as it had been done before... Ferrari once used screw-in liners years ago and I think a lot of aero engines have had screw-in liners. It's not an uncommon technique.
"With conventional construction you need quite large studs to pull the head down onto the top of the liner and ensure its sealing. The explosion loads are trying to blow the head off the block- they are trying quite hard to get a gas leak there! If you screw the liner into the head, there is almost no force trying to break the head joint. There is really no axial force on the liner as a result of gas pressure so you don't need a lot of force to seal it. So you don't need very big studs to hold the head on top of the block.
"You make quite a considerable saving in stud diameter and length. The stud bosses dont go right through the head to the top deck, you just use fairly small studs around the outside. So the water jacket is free of stud bosses, which are fairly intrusive. You get a lot of design freedom for your head. In addition to the weight saving you get a nice simple and stiff water jacket. Using screw-in liners we were also able to use reduced bore centres compared to conventional construction, which helped both size and weight. A complete OX11A engine without ECU and loom, was 99kg.
"I have to admit that it did take some time to get it working properly. It is more difficult in terms of manufacturing and assembly, though not that bad. In the first half of the '96 season we had a fair bit of trouble with the construction. We had to work very closely with Aeromet (Kent Aerospace as they were then) to improve the casting techniques.
"What we wanted imposed some severe requirements on the foundry. Virtually all castings have some material that doesn't pass the test bar specification, that is part of life. A lot of work was required to achieve the required properties in all parts of the casting where we needed it."
"...the key to [the OX11A's] dimensions and weight was some radical architectuure in the form of screw-in liners, as now patented by Yamaha."
Judd: "The idea of building the engine that way came from us but I wouldn't personally regard it as any kind of invention as it had been done before... Ferrari once used screw-in liners years ago and I think a lot of aero engines have had screw-in liners. It's not an uncommon technique.
"With conventional construction you need quite large studs to pull the head down onto the top of the liner and ensure its sealing. The explosion loads are trying to blow the head off the block- they are trying quite hard to get a gas leak there! If you screw the liner into the head, there is almost no force trying to break the head joint. There is really no axial force on the liner as a result of gas pressure so you don't need a lot of force to seal it. So you don't need very big studs to hold the head on top of the block.
"You make quite a considerable saving in stud diameter and length. The stud bosses dont go right through the head to the top deck, you just use fairly small studs around the outside. So the water jacket is free of stud bosses, which are fairly intrusive. You get a lot of design freedom for your head. In addition to the weight saving you get a nice simple and stiff water jacket. Using screw-in liners we were also able to use reduced bore centres compared to conventional construction, which helped both size and weight. A complete OX11A engine without ECU and loom, was 99kg.
"I have to admit that it did take some time to get it working properly. It is more difficult in terms of manufacturing and assembly, though not that bad. In the first half of the '96 season we had a fair bit of trouble with the construction. We had to work very closely with Aeromet (Kent Aerospace as they were then) to improve the casting techniques.
"What we wanted imposed some severe requirements on the foundry. Virtually all castings have some material that doesn't pass the test bar specification, that is part of life. A lot of work was required to achieve the required properties in all parts of the casting where we needed it."
#4
zac510
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Posted 03 November 2005 - 20:12
Interesting. I was trying to imagine earlier the forces acting on the liner but that article from RCE confirms that they are contained somewhat.
What do you think they used to screw in the liner? An 88mm allen key?
What do you think they used to screw in the liner? An 88mm allen key?
#5
McGuire
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Posted 04 November 2005 - 03:53
Originally posted by desmo
Judd: "The idea of building the engine that way came from us but I wouldn't personally regard it as any kind of invention as it had been done before... Ferrari once used screw-in liners years ago and I think a lot of aero engines have had screw-in liners. It's not an uncommon technique.
"With conventional construction you need quite large studs to pull the head down onto the top of the liner and ensure its sealing. The explosion loads are trying to blow the head off the block- they are trying quite hard to get a gas leak there! If you screw the liner into the head, there is almost no force trying to break the head joint. There is really no axial force on the liner as a result of gas pressure so you don't need a lot of force to seal it. So you don't need very big studs to hold the head on top of the block."
Exactly. Hispano-Suiza developed and perfected this method of construction for the first World War, built over 50,000 of them and it was widely duplicated and copied as well. Judd describes the issues precisely... many engines at this time employed non-detachable heads for the same reason, Miller and Bugatti to name two.
Daimler-Benz also used screw-in liners on the DB 601 series aircraft engines, and they were used again in the Ferrari Lampredi "big block" V12.
#6
soubriquet
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Posted 04 November 2005 - 09:10
DB601 with screw-in liners:
#7
McGuire
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Posted 04 November 2005 - 11:28
A nice shot last seen in my favorite thread, Crazy Engines. As noted there, the serrated nut-rings draw down and seal the opposite ends of the liners to the block.
Note some other interesting features...fork-and-blade rods, hollow rod journals, great big roller bearing on front main.
Note some other interesting features...fork-and-blade rods, hollow rod journals, great big roller bearing on front main.
#8
Halfwitt
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Posted 08 November 2005 - 21:55
Originally posted by scarbs
I believe (but stand to be corrected) teams use cast liners with coatings to reduce surface friction...
I think they use machined aluminium or steel liners with a 'Nicasil' coating on the bore.
#9
desmo
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Posted 09 November 2005 - 01:04
Didn't Renault at one point use a Nikasiled Al-alloy one-piece extrusion for each bank?
#10
hydra
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Posted 09 November 2005 - 07:06
Interesting...
I know that the adhesion of the nikasil coating is better for cast alloys than for wrought alloys. Makes you wonder why they went with an extrusion instead of a casting, knowing that a casting's fatigue strength wouldn't be much lower at elevated temperatures a liner would see, in addition to being less notch sensitive.
Besides, I thought extrusions couldn't be made with a maximum dimension over 12" or so?
I know that the adhesion of the nikasil coating is better for cast alloys than for wrought alloys. Makes you wonder why they went with an extrusion instead of a casting, knowing that a casting's fatigue strength wouldn't be much lower at elevated temperatures a liner would see, in addition to being less notch sensitive.
Besides, I thought extrusions couldn't be made with a maximum dimension over 12" or so?
#11
Halfwitt
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Posted 17 November 2005 - 23:30
Originally posted by desmo
Didn't Renault at one point use a Nikasiled Al-alloy one-piece extrusion for each bank?
I thought that the Renault blocks had always been a casting integral with the upper part of the crank-case; therefore no separate part carrying (or forming) the liners. I'd read a while ago that Renault are still using separate liners whilst most F1 engines are now linerless.
