pat

Andy,

The markings on the cams are "normal". For EJ20K heads they are normally labelled L4IN, L4EX, R4IN, R4EX, I would need to have a look at an EJ20G cam to see what markings they have, but it does kinda make sense that the earlier ones have a "3" designation.

With regard to whether the lifters are hydraulic, that's easy. If they have a "ring" machined into their periphery, with a small radial hole then they started life as a hydralic lifter (which may have been made solid at some point). If they are hydraulic and still in working order then it should be possible to compress the inside middle, and some oil may be expelled from the radial hole.

It is possible that someone has fitted a set of reprofiled cams at some stage. When one increases the lift by means of regrinding the base circle the lifter needs to be brought closer to the cam, so say 1mm was taken off the base circle, then it's easy to just put some 0.5mm top hat shims in there, for example, and continue to run the hydraulic lifters. If the cams have been reprofiled, often a marking is stamped into the cam wheel mating surface to identify the profile.

There SHOULD be markings on the journal caps. The heads have the journal surfaces ground with the caps installed, so they are matched; also there will be some distortion as they get bolted down, so machining them in situ ensure they're true when the cam gets installed. There will be a two letter marking on the head casting (eg "VU" or "TA"). The caps will have a marking identifying whether it's an intake or exhaust cap, the cylinder it's over, and the matching head casting ID.. eg I3TA would be the cap for the intake cam over cylinder 3 and it goes with the head that has an ID of "TA". Block halves have the same type of ID, because they too are ground assembled, and they are a matched pair... so if you're rebuilding a few engines you can't mix up the block pairs.. the grinding may be slightly offset.. a difference of 0.025mm in piston height is quite tolerable if the main bearing webs are ground lightly offset, but mix up a pair of blocks and you could crush the bearing shells down 0.025mm and it's bye-bye bearings, crank, engine.

Hope this helps,

Pat.

Andy.F

I need to borrow a digi cam again. Santa gave mine to John Banks in error

Andy.F

Cheers Pat, The followers have no groove, they are very thin and light, there is no way they could be concealing a hydraulic assembly !
Top hat type shims are not standard then ? What about the 30mm OD follower ?

What should the cam lift be as standard ? I can measure that tomorrow.

jameswrx

iTrader: (4)

Am I right in thinking that the ring landers break because of accoustics?
Prob sounds stupid but been thinking..it's late...lots of booze..
how do ring landers break otherwise.
I'm thinking coz of the accoustics detonation is producing and ring landers being the weakest part (physically) of the piston break (which is what they do, thay break, not melt, ones i've seen have cracked)
I can't see what else causes them to break other than detonation of the right frequencey breaking down the ring landers.
Flame suit on.
But don't understand why they'd fail otherwise?
Damaged ones I've seen don't look like heat damage.
James

Andy.F

Yes, Pressure wave basically.

pat

Andy,

I've not seen top hat shims used on Subaru heads (well, apart from my own, but that's different ), but that doesn't mean that there weren't one or two that left the factory with them in. The "normal" Subaru shimmed heads are either the UK / WRX over bucket type, which have a recess in the top to allow a 28mm shim to be popped into place, or the STi under bucket shims which sit in a recess in the valve retainer, but they are small (about 8mm if memory serves) but have no lip like a top hat shim.

With regard to follower diameter, EJ20K heads have 33mm diameter followers, with EJ20G having smaller hydraulic ones, looking at one suggests that it could well be 30mm, but I've misplaced my vernier so I can't measure it now. I think EJ205 (Phase II) heads have even larger followers. Lift depends on what the cams are out of, model year etc. They're nomally about 7.75mm up to about 8.5mm, but of course there are exceptions (such as STi III).

Cheers,

Pat.

R19KET

IIRC, the early solid lifter is "normally" 31mm. Andy, is there a brass sleeve that the follower slides in ?

Mark.

Pavlo

FWIW, Sti5 inlet cam measures at 8.3mm lift (not including clearance reduction).

11mm lift here we come...

Paul

pat

Some additional info... I measured a hydraulic lifter today, it is 29.95mm (ie to fit a 30mm bore), so it stands to reason that the heads started life as hydraulic ones (even if they were setup as solid at the factory). The cam markings with a "3" in them are also consistent with earlier hydraulic heads, I had a look at a set today and these too are marked L3IN, L3EX, R3IN, R3EX. I forgot to measure an EJ20K lifter, but I'm reasonably sure they're 33mm.

I'll try to do a bit more measuring on Monday.

Cheers,

Pat.

ustolemyname??stevieturbo

iTrader: (1)

Do the heads look modified in any other way Andy?? Any visible porting ?
Perhaps your cams have been re-profiled at some stage, which may explain your high power??

Andy.F

Solid lifter and top hat shim pics -




Valve caps, one shim in place. Brass/Bronze? follower sleeves -





Inlet ports look totally standard to me -





[Edited by Andy.F - 2/12/2003 11:31:19 PM]

Pavlo

Interesting that the upper land looks like it went some time ago, then the bottom has gone just recently.

I'm pretty sure the EJ20k followers are 32mm diameter.

20G looks nice BTW.

Paul

Andy.F

Yes, I'm sure the upper land had gone some time ago, it always had that scooby bumpy idle but with a bit added 'bump'
Good to know that the knocklink picked up the difference between 1 rattling land and 2 !!

C

maybe its me but if a ring land goes surely in normal circumstances it would score the liner?

Or should I get my rock out to crawl back under

Chris

Andy.F

I wouldn't use 'normal' and 'scooby' in the same sentence


No 4 bore



The bits of broken land were in their original location, with the rings on the piston, you could hardly even see the split line ! The piston looked perfect. Removed the rings and the 'bits' fell out.

C

Looks good to me

Would you normally expect that to happen then?

true what they say about scoobies and normal in one sentance

Chris

David_Wallis

you leaving the std rods and pistons in?

or are you replacing them with others??

if so what?

David

S,M,G

Andy I would say that the broken ring land is due to, too much compression (boost) a forged piston has a much stronger land, by keeping an eye on what you have when setting the car up you manage to keep det at bay but this is the next prob you face.At 1.7 bar your on boost comp is about 18.25:1. You can measure your cam lift by subtracting the base circle from the bottom of the base to the high point of the cam, hydrolic profiles are differant to solid lifter profiles to run any more than .400 lift you want a 31mm buckett. If you have top hat shims you must have sti valves as the other veriations dont have a nough stem to support a top hat shim
if you can put a pic up then i can tell you what you have, the top cap is also differant on sti. This is good news for you, you can run a good profile with this set up (if its what im thinking) and it will bo possible to machine the head to run a bigger bucket if your that keen.The later pistons are a shorter skirt with a teflon coated skirt and what apears to be some kind of anodising on the crown to help prevent the crown melting if det occours. The later pistons have a sqaure bowl this is to aid combustion, you can have a smaller quench zone that will in thery creat full combustion in this chamber and the chamber in the head, because the quench is small you will not get early combustion (pre ignition) meaning you can run more ignition and the flame front is kept away from the edge of the crown (Piston top) were melt down may start and also the compression ring of the head gasket.
Steve.
Steve.

Andy.F

Steve see pics above ^^^^^^^ in previous posts

cheers

Andy

S,M,G

Sorry mate got the flue and on a other planit today, looks like sti valve with std retainer, unless this is a early type i havnt seen yet, may be an idear to check the fitted spring lenght if someones been messing about if you take a valve out and post spring i/d and lenght we can see if it has sti springs or not, anyway thay are vales that are meant to run top hat so taking up the valve clearance that is the prob with repro cams due to reduced base-circle is a doddle with that set up. If you want to know how to work out what lift you can run with your spring set up let me know (or maybe you already know).
Steve.

David_Wallis

steve, new username?

David

S,M,G

David, yes mate changed email and never receiced a password.
Steve.

Andy.F

Cheers Steve

I'll get in and check the springs

David, not planning taking 'this' engine very far at the moment, think I'll throw in a set of std Sti pistons and just see what the TD05/06 hybrid can do with a standard motor. If I can get 400 flywheel I'll be very happy (for a while ))

The Cam lift is 8.1mm. Less clearance, that makes it pretty much standard lift of 7.8mm. Good to know there's potential though

Andy

David_Wallis

std rods still?

David

Andy.F

Yes. Std rods Just not going to rev it anywhere near the Sti rpm limit. 7k rpm max. If I can get 370 at 6k then 400 should come before 7k ? maybe

Pavlo

I just measured the followers on my sti5 heads, they are nominally 35mm, fat buggers!

They have flat, under bucket shims.