Few more head pics and graphs
Scooby Regular
Joined: May 2002
Posts: 6,316
Likes: 2
From: home
David,
you can't fit cossie followers in your head, sorry, but that's just the cruel world we live in.
but
you can rip out the hydraulic part and ram in a small "bit" to take some under bucket shims.
welding the hole just stops the oil getting in and pumping up the now solid follower.
But essentially yes, you don't need special heads, just frig the ones you've got and get some cams. But it might be cheaper to just get heads from the right model of impreza, Pat mentioned his 97 uk car (i think that's right) revved like crazy, powering up to 7000rpm, the RR operater kept hitting the rev limit.
Any 93-98 head would fit no trouble, ignition coils might be an issue unless you can fit the old cam cover to the new head.
FWIW I was given a price of 350+vat for a pair of legacy twin turbo heads with solid lifters etc.
P
you can't fit cossie followers in your head, sorry, but that's just the cruel world we live in.
but
you can rip out the hydraulic part and ram in a small "bit" to take some under bucket shims.
welding the hole just stops the oil getting in and pumping up the now solid follower.
But essentially yes, you don't need special heads, just frig the ones you've got and get some cams. But it might be cheaper to just get heads from the right model of impreza, Pat mentioned his 97 uk car (i think that's right) revved like crazy, powering up to 7000rpm, the RR operater kept hitting the rev limit.
Any 93-98 head would fit no trouble, ignition coils might be an issue unless you can fit the old cam cover to the new head.
FWIW I was given a price of 350+vat for a pair of legacy twin turbo heads with solid lifters etc.
P
Coils bolt on no probs. Mates car has a MY 98 UK motor, and it us running 4 coils. I dont recall doing anything specific to bolt them up, so they obviosuly do. The engine also has solid lifters, and was a single coil manifold, although the engine is in a legacy with 4 coils.
Im just not sure that all the camshaft bearing diameters/oil seals etc etc are the same from hydraulic-mechanical, so not sure if its just as easy as swapping cams. Might not be an issue of you get your own reground.
Im just not sure that all the camshaft bearing diameters/oil seals etc etc are the same from hydraulic-mechanical, so not sure if its just as easy as swapping cams. Might not be an issue of you get your own reground.
Thread Starter
Scooby Regular
Joined: Jan 2002
Posts: 128
Likes: 0
David, yes as pavlo says use your heads etc, nice set of cams. This
cossie solid lifter im going to use is a light weight one piece
lifter that is ment to run with a top hat shim similer to the one in the pic, but dew to the way the valve set up is on most scoobs
this can not be done (some sti are differant). So i am going to
use the lifter by its self just there is no room for error on the shimmimg as a slot drill or end mill is used for removing the material from the bucket. The buckets are about £15 each and are
very nice indeed. Getting to the point, i have a set of heads that
are phase 1 but have cossie size lifter bores, i think you wiil
find that your smaller lifters run in a bronze liner that is pressed into the head. I can see no reason why this can not be bored out to take cossie size lifters, i shall be boring your type
of head to see how this turns out, if you would like i can let you
know the out come.
Carlos sorry mate o/d of pipe is 72mm.
Steve
cossie solid lifter im going to use is a light weight one piece
lifter that is ment to run with a top hat shim similer to the one in the pic, but dew to the way the valve set up is on most scoobs
this can not be done (some sti are differant). So i am going to
use the lifter by its self just there is no room for error on the shimmimg as a slot drill or end mill is used for removing the material from the bucket. The buckets are about £15 each and are
very nice indeed. Getting to the point, i have a set of heads that
are phase 1 but have cossie size lifter bores, i think you wiil
find that your smaller lifters run in a bronze liner that is pressed into the head. I can see no reason why this can not be bored out to take cossie size lifters, i shall be boring your type
of head to see how this turns out, if you would like i can let you
know the out come.
Carlos sorry mate o/d of pipe is 72mm.
Steve
Scooby Regular
Joined: Nov 2001
Posts: 15,239
Likes: 1
From: Leeds - It was 562.4bhp@28psi on Optimax, How much closer to 600 with race fuel and a bigger turbo?
definiteley interested to find out how it goes... could you drop me a mail with a price to modify my heads and fit the cams as well??
David
David
Thread Starter
Scooby Regular
Joined: Jan 2002
Posts: 128
Likes: 0
David YHM, Scot123 its a superflow 120 bench thought about making
one but would of been a nightmare, and to get reocouring accurate
readings well thats why i gave up, my bench takes into acount the test temp and the flow temp and has a stepper motor that keeps the flow presure constant.
My vernier pulleys turned up today so i will put up a pic later.
Steve
one but would of been a nightmare, and to get reocouring accurate
readings well thats why i gave up, my bench takes into acount the test temp and the flow temp and has a stepper motor that keeps the flow presure constant.
My vernier pulleys turned up today so i will put up a pic later.
Steve
I asked elsewhere, but I'll do it here too. SInce you have the veriniers, have you any infe regarding the std cam timing, and what its supposed to be, or what improvements may be made to it.
For all we know, there may be a few horses simply by timing the cams accurately.
For all we know, there may be a few horses simply by timing the cams accurately.
Scooby Regular
Joined: May 2001
Posts: 1,835
Likes: 0
Stevie,
on the rally cars they advance (I think it is advance
) the cams by one notch on the cam belt to get a lot more torque out of the engine - it kills the top end power tho - but gives great torque figures.
Good on a Group N car with a restrictor as top end power is limited anyway.
I guess with Verniers you could try different settings - also vary the inlet and exhaust settings to get different results - ultimately they are all compromises in the end.
Trout
on the rally cars they advance (I think it is advance
) the cams by one notch on the cam belt to get a lot more torque out of the engine - it kills the top end power tho - but gives great torque figures. Good on a Group N car with a restrictor as top end power is limited anyway.
I guess with Verniers you could try different settings - also vary the inlet and exhaust settings to get different results - ultimately they are all compromises in the end.
Trout
Subaru Tuning Specialist
Joined: Jun 2002
Posts: 6,654
Likes: 1
From: 7.74 @179 mph 1/4 mile - road legal
they advance (I think it is advance ) the cams by one notch on the cam belt to get a lot more torque out of the engine
Advance all, by one tooth? or advance the crank by one tooth?
Does anyone even know the standard cam data?? for example blueprinting..When they build a blueprinted engine, as well as tolerances, dont they have the cams timed to factory spec accurately ?
Does anyone even know the standard cam data?? for example blueprinting..When they build a blueprinted engine, as well as tolerances, dont they have the cams timed to factory spec accurately ?
Looks good, are they the kent ones, or another make? I think it may be a bit time consuming timing the cams, but if there was a gain to be had, my time, for me is free. I think I want cams too though. Wonder if any cam suppliers want a guinea pig who they can donate some gear to for free.
Scooby Regular
Joined: Nov 2001
Posts: 15,239
Likes: 1
From: Leeds - It was 562.4bhp@28psi on Optimax, How much closer to 600 with race fuel and a bigger turbo?
Quoting info from Julian Edgars 21st Century performance book
No MY specified, just EJ20 subaru turbo
Intake 3/55 Exhaust 55/11
duration 238 duration 246
Overlap 14 degrees.
No mention of lift
What MY98 is that Steve? STI, or UK and what lift?
No MY specified, just EJ20 subaru turbo
Intake 3/55 Exhaust 55/11
duration 238 duration 246
Overlap 14 degrees.
No mention of lift
What MY98 is that Steve? STI, or UK and what lift?
Judging by the results of your flowbech testing, what we really need, is modified heads, and cams with about 0.450-0.480" lift??
What is the max valve lift we can actually achieve, without smashing them off the pistons or each other?
What is the max valve lift we can actually achieve, without smashing them off the pistons or each other?
Thread Starter
Scooby Regular
Joined: Jan 2002
Posts: 128
Likes: 0
This would be uk spec and .365 lift, i have come across a few std
cams with verious specs. I am trying some cams similer to the high
lifts you mention. One thing to keep in mind in with increased lift
you need valve pockets to match, ive had some pistons made with deep valve pockets, my self i make sure there is a min of .050" between the valve and piston.
Steve
cams with verious specs. I am trying some cams similer to the high
lifts you mention. One thing to keep in mind in with increased lift
you need valve pockets to match, ive had some pistons made with deep valve pockets, my self i make sure there is a min of .050" between the valve and piston.
Steve
So what would be the best std cam spec to look for? Are the STI cams actually any different from UK spec cams? Later model perhaps??
Just a pity new ones are so expensive, or I could easily be tempted to try some. I also sort of need a head change, as one of my camshaft thrust plates is broken ( from a crashed engine, but I superglued it back together, and it actaully sealed for a long time ) and leaks a bit of oil.
Just a pity new ones are so expensive, or I could easily be tempted to try some. I also sort of need a head change, as one of my camshaft thrust plates is broken ( from a crashed engine, but I superglued it back together, and it actaully sealed for a long time ) and leaks a bit of oil.
There is some cam specs, for various models on this site.
http://www5a.biglobe.ne.jp/~miner/Impreza/misc_dataeg.html
using this site to translate
http://world.altavista.com/
Roughly i think..
wrx models
inlet 6/56 7.5mm lift
exhaust 55/11 7.5mm lift
early sti models ( incl ra )
in 10/56 8.2mm lift some later have 7.8mm lift
ex 56/12 8.3mm lift
+ a few variations on that.
[Edited by ustolemyname??stevieturbo - 9/7/2002 4:27:30 PM]
http://www5a.biglobe.ne.jp/~miner/Impreza/misc_dataeg.html
using this site to translate
http://world.altavista.com/
Roughly i think..
wrx models
inlet 6/56 7.5mm lift
exhaust 55/11 7.5mm lift
early sti models ( incl ra )
in 10/56 8.2mm lift some later have 7.8mm lift
ex 56/12 8.3mm lift
+ a few variations on that.
[Edited by ustolemyname??stevieturbo - 9/7/2002 4:27:30 PM]
