well they're still not physically the same cam like a SOHC.. you could just move one of the cams one cog over on the scissor gear to make a rudimentary adjustment couldnt you?Originally Posted by ed_jza80
see pic:
now typically, retarding the exhaust cam, and advancing the intake cam will improve overlap.
on a SOHC this cant be adjusted independantly, advance the intake, you advance the exhaust, the overlap stays the same.
on a GE DOHC head, they can be done independantly.
On an FE head, the scissor gear makes the cams act the same as a SOHC... hence you advance the intake, you advance the exhaust, and overlap stays the same. the confusing bit is obvously as the cams are scissor geared, the cams counter rotate. BUT this only really means that the grind on the exhaust cam needs to be 'backwards' in order for the profile to rotate 'forwards' in the converntional twin cam sense. its still 'linked' to the intake cam such that the 2 cams act like a SOHC in an adjustment sense
ed
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E46 M3 Nürburgring Nordschleife - 8.38
well they're still not physically the same cam like a SOHC.. you could just move one of the cams one cog over on the scissor gear to make a rudimentary adjustment couldnt you?Originally Posted by ed_jza80
Does anyone know how many degrees the cam is rotated by moving the scissor gear one tooth?
Teh UZA80 - Project Century - Remotely p00'd by association
360 / number of teeth.. how many teeth they got though? looks like about 40-50 or so.. i guess anywhere between 7 and 9 degrees..Originally Posted by JustCallMeFrank
erm, if you advance the intake one tooth, in relation to the exhaust, but leave the camwheel in the same place in relation to the belt, you will just retard the exhaust cam... you would have to advance it on both..
That's my point, but I was just curious to the number of teeth.
Teh UZA80 - Project Century - Remotely p00'd by association
the typical timing belt pulley has 48teeth, so i doubt those scissor gears have 40-50, perhps closer to 30.
and are we measing on a 360deg scale or a 720deg scale? either cae, one cog on the scissor gear is HUGE. hell, one cog on a typical timing gear is huge and unusable...
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E46 M3 Nürburgring Nordschleife - 8.38
sif you didnt know all FE heads were driven by a single gear from the timing belt/chain, with a scissor gear arrangement rotation both camshafts in unison.....
..... thats like, the definition of a Toyota FE head
useful post though, just to clear up any confusion.
...... butt scratcher?!
karl, apparently the issue needed clarifying from another, now locked thread. hence the post. PS - you have a PWM and handset for me? Stitt give you thie hinges?Originally Posted by The Witzl
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E46 M3 Nürburgring Nordschleife - 8.38
yeah I just read the other thread.... and have pointed to the most useful information resource in the world for the guys who are trying to understand.
I have a DPA (digital pulse adjuster) kit.... kinda. Needs a couple of modifications before i can give it to you =P
Hand controller is complete and functional though.
Stitt.... has done nothing
...... butt scratcher?!
Ed, from the pic above, you can see about 20 teeth on half of the gear, so about 40-45 total.. per 720deg, 1 tooth = 18deg = farkin heaps.Originally Posted by ed_jza80
"I'm a Teaspoon, not a mechanic"
"There is hardly anything in the world that a man can not make a little worse and sell a little cheaper" - John Ruskin (1819 - 1900)
AU$TRALIA... come and stay and PAY and PAY!!! The moral high horse of the world!
stewy, i can see 16per half = 32total = 22.5deg :/
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E46 M3 Nürburgring Nordschleife - 8.38
perfect!! so about 5 or 6 cogs over should sweeten the valve timing..Originally Posted by ed_jza80
Advance. The scissor gears will ensure the exhaust cam has the same timing relative to the intake cam. Prove it to yourself with a dial indicator.advancing the intake cam does 'what' to the exhaust cam... ??
Get adjustable scissor gear ftw.
As the infomercial goes, "Set it and forget it."
oh ..... what does it look like in real life?Originally Posted by ed_jza80
"I'm a Teaspoon, not a mechanic"
"There is hardly anything in the world that a man can not make a little worse and sell a little cheaper" - John Ruskin (1819 - 1900)
AU$TRALIA... come and stay and PAY and PAY!!! The moral high horse of the world!
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