Camshafts for the EG33.

[icingdeath88]

Originally Posted by bazza

The only rule I stick with hydraulics is to use a SOFT RPM limiter only. A hard rpm limiter going off can pump the buckets up and you can lose compression in all cylinders for a few seconds.. BAD.

Can you explain this a bit? I Googled hard/soft rev limiter and got not very consistent results. Also what you mean about the hydraulic lifters and losing compression.

[svxfiles]

Are lighter/stronger (titanium) retainers/keepers available for our stock valves?
Just to lighten the load.

[bazza]

Originally Posted by icingdeath88

Can you explain this a bit? I Googled hard/soft rev limiter and got not very consistent results. Also what you mean about the hydraulic lifters and losing compression.

For whatever reason during a hard ECU rev limit cut (after market ecu) you get the hydraulic buckets "pumping" up full of oil. I'm not sure if it's the shockwave of the backfire or whatever. The end result is the valves do not close completely and you can lose compression until they sort them selves out. It happened on the EG33 before I figured out what it was doing and it also used to happen on an old EJ20 I had which ran the hydraulic buckets.

Btw for my ecu hard cut is exactly that - fuel and spark completely cut off. The result is the sound of a cannon going off. Soft cut just cuts some of the cylinders and can cut either fuel or ignition or both. All depends on the ecu and it all depends on the settings you put in as it's all customisable.

[SVXRide]

Originally Posted by svxfiles

Are lighter/stronger (titanium) retainers/keepers available for our stock valves?
Just to lighten the load.

Tom,

Good idea! Ti's density is ~55-56% of steel's. Supertech makes stock sized valves for the EG33 (SS intakes, Inconel Exhaust), so I'd think that they'd be a good place to start for Ti retainers/keepers. If memory serves me right, I think you can get a full set of valves from them for around $500-600.

Bill

[dragoontwo]

Originally Posted by SVXRide

Supertech makes stock sized valves for the EG33 (SS intakes, Inconel Exhaust)

Correct me if I'm wrong, but supertech lists the EG33 valves as: 92.1mm intake, and 92.7mm exhaust. Stock lengths are: 90mm intake, and 90.85 exhaust.

[SVXRide]

Originally Posted by dragoontwo

Correct me if I'm wrong, but supertech lists the EG33 valves as: 92.1mm intake, and 92.7mm exhaust. Stock lengths are: 90mm intake, and 90.85 exhaust.

This is what I read from Supertech:

Intake Valve -- SIVN-1080 -- 36.00mm Head Diameter, 5.96mm Stem Diameter, 92.10mm Length

Exhaust Valve -- SEVI-1080 -- 32.00mm Head Diameter, 5.96mm Stem Diameter, 92.70mm Length

Which matches what you've noted. Not having my shop manuals with me, I'll have to depend on others here on the Network to confirm the stock lengths. I'm not sure why Supertech would offer non-stock length valves, given the inherently limited audience for them in the first place (i.e., larger audience for stock than non-stock??)

Bill

[RallyBob]

Originally Posted by SVXRide

I'm not sure why Supertech would offer non-stock length valves, given the inherently limited audience for them in the first place (i.e., larger audience for stock than non-stock??)

Bill

Well, it seems that slightly taller valves, taller springs, and reground cams (smaller base circle) would work nicely together with hydraulic buckets and allow for more valve lift than the stock valve train would normally allow.

[dynomatt]

Bob, aren't the valve springs the limitation to getting lift? If they've changed the installed height, they'll compromise the installedp spring pressure too...which would have disasterous results (just ask me).

M

[SVXRide]

Originally Posted by RallyBob

Well, it seems that slightly taller valves, taller springs, and reground cams (smaller base circle) would work nicely together with hydraulic buckets and allow for more valve lift than the stock valve train would normally allow.

Bob,

Which makes sense. Why then doesn't Supertech offer springs to go with the valves? Are the EZ springs interchangeable with the EG's?

Bill

[dynomatt]

Doh...I misread the slightly longer springs bit...my bad.

Sorry Bob.

M

[oab_au]

Originally Posted by bazza

Indeed. Big lift would be nice. However when you start increasing lift and upgrading springs you turn the head into a full race head. Which means very high maintenance, increased risk of breaking valves, hammering seats and guides etc and this is something my mate and I didn't want to do or have to R&D. We want reliable track motors with mimimal maintanence which means keeping it close to stock design as possible.

As for hydraulic buckets they're absolutely fine for my purpose. They'll do 6500-7000 rpm all day long:
http://www.youtube.com/watch?v=qssbthwIb4s

The only rule I stick with hydraulics is to use a SOFT RPM limiter only. A hard rpm limiter going off can pump the buckets up and you can lose compression in all cylinders for a few seconds.. BAD.

Solids would be nice but given the "PITA" factor and the cost I'd only recommend them for a NA engine like Jack's or what Tony is planning on building.

P.S. My mate wanted the heads and cams profiled to ensure we didn't make any mistakes - I believe his brand new billets arrive today

Gee Bazza, I can see that you are determined to go your way, so I won't deter you., but there are a few things that need to be straightened out.

The EZ30R runs 10mm lift on solids, this is common on a lot of production engines, not really a race motor.

So we're going to run 8-9.5 mm lift with massive duration - LAN already has shown these to work and Kelford show in there charts that this can easily be done. Something else to note is you don't actually need more lift than that - the stock heads flow huge amounts to that lift however above that lift the heads don't really increase in flow (based on our flow figures) - HOWEVER this flow still supports 400 maybe even 500 kw ATW. So as you can see there aren't really any positives for us running lots of lift for the planned 300-400 kw atw. Above that yes.

I can see that you don't understand the benefits of big lift.

You say that the flow bench shows that 9mm is really the maximum lift for flow. That is when the area of the open valve matches or exceeds the valve throat area, and the throat dia is limiting the flow. What the flow bench does not show is how much, when, and for how long.

If you use 9mm, you are getting the maximum flow at maximum opening point, for maybe 10/15* but each side of that it is not maximum. it is either opening or closing, and port flow is at less than max.

This is a diagram of two 240* profiles, one at 9mm and one at 12 mm



You can see that the line at 9mm shows the max port flow, which the 9mm lift cam just reaches, for 10/15*. The 12mm lift cam reached the 9mm max port flow early, and it maintains max port flow right through max lift, till the valve has closed down to the 9mm lift point, almost 90* of max port flowing air into the cylinder. This is the benifit of using the higher lift.

You also say " massive duration ", massive duration is for massive rpms, but you are only reving to 7000, the standard duration will cover that speed without any loss of torque spread.

Harvey.

[bazza]

Originally Posted by oab_au

Gee Bazza, I can see that you are determined to go your way, so I won't deter you., but there are a few things that need to be straightened out.

The EZ30R runs 10mm lift on solids, this is common on a lot of production engines, not really a race motor.

Indeed they do but you miss my point. The EG33 came out of the factory with valves, guides, cams, springs and rocker covers all designed and engineered to run with the sub 8 mm lift. The EZ30R was designed in the factory to run 10mm lift. Making an EG33 run >10 mm lift and be very reliable with minimal maintainence was something we were not interested in having to R&D. The amount of effort required to get the big lift cams working far out weighs the benefits for a turbocharged EG.

I can see that you don't understand the benefits of big lift.

You say that the flow bench shows that 9mm is really the maximum lift for flow. That is when the area of the open valve matches or exceeds the valve throat area, and the throat dia is limiting the flow. What the flow bench does not show is how much, when, and for how long.

I do understand them (at a basic level) but you're trying to over engineer something that doesn't require it. If we can push the billet or reground cams to 7000-8000 rpm and make 300-400 kw atw and have the engine pull to redline with ~9mm lift then it's a great win. The cost for me is < $400 to do this to the cams. Stuffing around with bigger lift will require a valve train upgrade - springs, retainers, valves, buckets and a lot of custom work plus increased maintenance etc etc. We're talking $2K to do it AND for what real benefit?

If you use 9mm, you are getting the maximum flow at maximum opening point, for maybe 10/15* but each side of that it is not maximum. it is either opening or closing, and port flow is at less than max.

This is a diagram of two 240* profiles, one at 9mm and one at 12 mm

You can see that the line at 9mm shows the max port flow, which the 9mm lift cam just reaches, for 10/15*. The 12mm lift cam reached the 9mm max port flow early, and it maintains max port flow right through max lift, till the valve has closed down to the 9mm lift point, almost 90* of max port flowing air into the cylinder. This is the benifit of using the higher lift.

You also say " massive duration ", massive duration is for massive rpms, but you are only reving to 7000, the standard duration will cover that speed without any loss of torque spread.

Harvey.

I agree with what you're saying but again why over engineer something? A previous engine combination in my car was 272 cams with 230 @ 50 thou. 10.5 / 11.5 mm lift or thereabouts and it had both insane midrange and revved beautifully. Reducing the lift will reduce the low end torque will it not? It's a turbo 3.3L... I can live with that given it should be between 4500-7000 rpm at the track and lack of torque is easily fixed if required with increased boost.

[RallyBob]

Originally Posted by oab_au

You can see that the line at 9mm shows the max port flow, which the 9mm lift cam just reaches, for 10/15*. The 12mm lift cam reached the 9mm max port flow early, and it maintains max port flow right through max lift, till the valve has closed down to the 9mm lift point, almost 90* of max port flowing air into the cylinder. This is the benifit of using the higher lift.

Yes! Glad you understand this and took the time to explain it.

A lot of people don't, and instead they order cams that peak at *exactly* the lift at which max airflow is achieved. There is far more 'area under the curve' when you approach it the way you have. Without altering the seat-to-seat duration, you have effectively increased the duration of the cam at peak airflow. More time to fill the cylinder without increasing overlap!

[oab_au]

Originally Posted by RallyBob

Yes! Glad you understand this and took the time to explain it.

A lot of people don't, and instead they order cams that peak at *exactly* the lift at which max airflow is achieved. There is far more 'area under the curve' when you approach it the way you have. Without altering the seat-to-seat duration, you have effectively increased the duration of the cam at peak airflow. More time to fill the cylinder without increasing overlap!

Yes Bob a lot of people going to build an engine, get blinded by the bling of the 'shopping cart' and big numbers. They loose sight of the main objective, that is to fill the cylinder with as much air as you can, and then, shut the inlet valve when the cylinder pressure is at the highest. Every thing else is just house keeping to support that objective.

If the valves and ports are big enough to flow max air, and the pressure difference between the inlet tract inertia outside, and the negative sonic pressure inside, we will achieve the best Volumetric Efficiency, and the best torque.
All the cam timing has to do is shut the inlet valve when that pressure is achieved.

The four valve engine doesn't need valve overlap like the older two valve engines, that relied on exhaust inertia to pull the inlet air down the tract. In the two valve hemi chamber the valves are opposite each other, but the inlet port was angled to direct the air down and to the side of the exhaust valve.
The four valve chamber has the inlet ports directly opposite the exhaust, so at overlap the air goes across the roof of the chamber and out the exhaust.
So we don't need overlap to start the air flow, as we can use the greater negative sonic pressure to start the inlet wave.
This is why the duration of the four valve is a lot less that the two valve engine. We only need to open the valve on the negative pressure, that we can time to arrive, by fixing the exhaust length.

Harvey.

[bazza]

Some good theory there guys.

Out of interest Harvey, have you got a built EG33 sitting in your shed with this theory applied? I find a lot of people love to give advice based on sound theory but very few of those people have actually put their own hard earned money into what they theorise about and fewer have proven results. I imagine you will have and I'd be interested in what it's running etc.