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All of those look like NA (naturally aspirated) profiles.
There were three different set ups listed in your list.
Which one did you get?
Altering exhaust cam timing MAY help you because you may have too much overlap now.
If you had a poorly flowing exhaust manifold and turbo (you have the best flowing stuff NOW IMO) this late boost threshold would be substantially worse.
I think you have "too much" cam for the compression and application but I could well be wrong and I am very interested in Emilio's take on this.
It's easy to alter exhaust timing to test this theory. It's a PIA to purchase different cams.
Putting big camshaft profiles into a turbo application is tricky.
All of those look like NA (naturally aspirated) profiles.
There were three different set ups listed in your list.
Which one did you get?
Altering exhaust cam timing MAY help you because you may have too much overlap now.
If you had a poorly flowing exhaust manifold and turbo (you have the best flowing stuff NOW IMO) this late boost threshold would be substantially worse.
I think you have "too much" cam for the compression and application but I could well be wrong and I am very interested in Emilio's take on this.
It's easy to alter exhaust timing to test this theory. It's a PIA to purchase different cams.
Putting big camshaft profiles into a turbo application is tricky.
Emilio actually spoke positively about these in a turbo application.
This is all you need!
I wish those cam specs showed what lift the duration readings were taken at.
If those are total timing they're not nearly as "big" as if they were taken at .050 lift like domestic stuff is.
The specs didn't list duration at XX lift anywhere.
It's also interesting that the 16 lifter "kit" is $50 more than ordering 16 lifters individually.
This seems backwards...
How did the shims work out?
Did you assemble, measure, then order shims?
Or did you just have Super Miata supply the head complete and assembled?
I'm envious of your build.
It looks like it should be super reliable at the power levels you are at.
That Tomei profile is the shortest duration they offer and why they work pretty well for both N/A and forced induction. Increase the duration much more than that and they require really high revs to make any power and the motors don't last very long. The lift is also in the range that is pretty easy to get the valve train to survive. Start getting into the .450 to .500 lift and the valve train doesn't last very long.
On an N/A engine, they usually bump the torque peak up 4 to 700 RPM depending on what else you've done to it. For Rotrex, it's just like adding big valves more power everywhere. For a medium size turbo, the torque hit will be a little bit more abrupt than it would be with the stock cam. You might actually make more torque down low than stock cams but because the hit is a little bit more abrupt it can make the bottom a bit feel soft in comparison. Anyway for a BP that's going to be driven on the street I always recommend keeping the duration as short as possible.
That Tomei profile is the shortest duration they offer and why they work pretty well for both N/A and forced induction. Increase the duration much more than that and they require really high revs to make any power and the motors don't last very long. The lift is also in the range that is pretty easy to get the valve train to survive. Start getting into the .450 to .500 lift and the valve train doesn't last very long.
On an N/A engine, they usually bump the torque peak up 4 to 700 RPM depending on what else you've done to it. For Rotrex, it's just like adding big valves more power everywhere. For a medium size turbo, the torque hit will be a little bit more abrupt than it would be with the stock cam. You might actually make more torque down low than stock cams but because the hit is a little bit more abrupt it can make the bottom a bit feel soft in comparison. Anyway for a BP that's going to be driven on the street I always recommend keeping the duration as short as possible.
Thanks Emilio! Thoughts on my current engine revving to 8k and the reliability of such?
Thanks Emilio! Thoughts on my current engine revving to 8k and the reliability of such?
Should be fine up to 500whp or so. Keep oil pressure above 45psi under boost, preferably 55psi and <240°. Sometimes that means shimming pump, adding oil cooler or running higher viscosity oil. Assuming no cat, run race oil, lots more zinc. When a BP goes bang at high revs/boost, it's almost always rod big end. If you can source billet main caps, I'd add them next time you're in the motor, and line bore it. 6258, I wouldn't bother. We made 450whp with a similar setup on a 6258 so I think yours could hit 550whp.
Might need the HB studs if you run E85 and lots of boost and timing. Mots of the builds running regular ARP studs run less timing that I did (21°) so less peak cylinder pressure.
Stock crank is fine at that power level provided you aren't also spinning it to 9k. The BP's that break cranks are going above 9k. Plenty of 500-700whp BP's surviving on stock but blueprinted, polished, balanced cranks.
I wish those cam specs showed what lift the duration readings were taken at.
If those are total timing they're not nearly as "big" as if they were taken at .050 lift like domestic stuff is.
The specs didn't list duration at XX lift anywhere.
It's also interesting that the 16 lifter "kit" is $50 more than ordering 16 lifters individually.
This seems backwards...
How did the shims work out?
Did you assemble, measure, then order shims?
Or did you just have Super Miata supply the head complete and assembled?
I'm envious of your build.
It looks like it should be super reliable at the power levels you are at.
@technicalninja Honestly, I just bought the supermiata sub kit and took it to a head shop, then cut them a check. In hindsight, I wish I had asked SuperMiata for their shop and just had them ship everything to their shop, then ship me a fully assembled head. That would have been the best result for everyone.
This is an important tip!
Rip your valve cover off and check valve clearance YOURSELF! if you haven't already.
Shim under bucket (best IMO) takes a real competent technician to get right.
You yourself are MOST LIKELY more competent than the head shop.
There are very very FEW machine shops that are really competent.
They exist but it's 1/50 in my experience.
Machine shops usually try to hit a "range" around a specific target clearance.
Commonly the range is +/- .002 so a total range of .004
When I'm setting up an appliance car, lots of everyday Toyotas and Korea cars have SUB or SIB (shim IS bucket), I'll try to hit +/- .001 with a total range of .002.
For something like you have there (world class stuff) I'll try to hit +/- .0005 with a total range of .001.
This is a PIA but worth it in the long run.
If your valve adjustments are all over the place then your cam timing events are also all over the place. You can have significantly different compression readings with a range of .004. It doesn't matter on an appliance car with wimpy duration numbers.
It WILL matter on a 400+ HP BP build with nice cams.
You need to EITHER be a freaking Wizard at cutting the valves to hit the shims that came in the kit OR (far more common) have a bunch of the shims for your set up in different thicknesses...
Another way to "skin the cat" is to start with shims that are too thick and grind the shims INDIVIDUALLY on a little surface grinder. This works great (+/- .0005 is EASY) and may be what your head shop did.
The OEM seem to love specing shim diameters different than each other so having a bunch of working shims is rare unless...
Mazdas are what you do. Like Super Miata. I'd bet they have a shim box for SUB stuff, a fairly heavy box with lots of different thicknesses.
I'm currently building a 2UZ V8 Toyota 32 valve engine. I'm working with a new machine shop but he's used to doing Korean stuff which requires very expensive buckets to adjust clearance. He cuts the valves to hit proper clearance with the buckets that came in with the head.
He is the first machinist I've worked with that I think has a chance to hit it right but the juries still out until I bolt the heads on and check clearances myself. I'm hopeful as the freaking shims themselves are $15 each!
He goes +/- .002 normally.
He tried to hit +/- .0005 for me.
If he did he will get fully assembled heads from me and I'll let him do everything from now on.
I haven't taken assembled heads to ANY machine shop in 2 decades...
The 2UZs were fully dissembled when I took them to him.
But it's super easy to verify you're fine or you're screwed.
This is an important tip!
Rip your valve cover off and check valve clearance YOURSELF! if you haven't already.
Shim under bucket (best IMO) takes a real competent technician to get right.
You yourself are MOST LIKELY more competent than the head shop.
There are very very FEW machine shops that are really competent.
They exist but it's 1/50 in my experience.
Machine shops usually try to hit a "range" around a specific target clearance.
Commonly the range is +/- .002 so a total range of .004
When I'm setting up an appliance car, lots of everyday Toyotas and Korea cars have SUB or SIB (shim IS bucket), I'll try to hit +/- .001 with a total range of .002.
For something like you have there (world class stuff) I'll try to hit +/- .0005 with a total range of .001.
This is a PIA but worth it in the long run.
If your valve adjustments are all over the place then your cam timing events are also all over the place. You can have significantly different compression readings with a range of .004. It doesn't matter on an appliance car with wimpy duration numbers.
It WILL matter on a 400+ HP BP build with nice cams.
You need to EITHER be a freaking Wizard at cutting the valves to hit the shims that came in the kit OR (far more common) have a bunch of the shims for your set up in different thicknesses...
Another way to "skin the cat" is to start with shims that are too thick and grind the shims INDIVIDUALLY on a little surface grinder. This works great (+/- .0005 is EASY) and may be what your head shop did.
The OEM seem to love specing shim diameters different than each other so having a bunch of working shims is rare unless...
Mazdas are what you do. Like Super Miata. I'd bet they have a shim box for SUB stuff, a fairly heavy box with lots of different thicknesses.
I'm currently building a 2UZ V8 Toyota 32 valve engine. I'm working with a new machine shop but he's used to doing Korean stuff which requires very expensive buckets to adjust clearance. He cuts the valves to hit proper clearance with the buckets that came in with the head.
He is the first machinist I've worked with that I think has a chance to hit it right but the juries still out until I bolt the heads on and check clearances myself. I'm hopeful as the freaking shims themselves are $15 each!
He goes +/- .002 normally.
He tried to hit +/- .0005 for me.
If he did he will get fully assembled heads from me and I'll let him do everything from now on.
I haven't taken assembled heads to ANY machine shop in 2 decades...
The 2UZs were fully dissembled when I took them to him.
But it's super easy to verify you're fine or you're screwed.
Just check your valve adjustment yourself...
Ouch. Serious question, I get a tick on startup with solid lifters that I'm having trouble explaining. Could this be from misadjusted valves?
Another tip (here's where I disagree with the almighty Emilio whom I respect HIGHLY!)
Screw the CAT...
If you have one.
That critter NEEDS race oil ONLY.
Aftermarket cats are cheap and EASY to change.
Internal engine wear on what you have built is NEITHER cheap or easy.
Run oil high in ZDDP or add ZDDP to the oil you are running.
Replace $300 cat every 25K if you have one installed.
I'd check the valve clearances anyway.
Significant noise on a build like that would "Dead Line" the engine for me.
No more operation until noise issue diagnosed/fixed.
Too loose makes noise...
Too tight eats wallet and time...
Death is silent here.
Last edited by technicalninja; 02-21-2021 at 05:59 PM.
Reason: Only the ninja knows...
Another tip (here's where I disagree with the almighty Emilio whom I respect HIGHLY!)
Screw the CAT...
If you have one.
That critter NEEDS race oil ONLY.
Aftermarket cats are cheap and EASY to change.
Internal engine wear on what you have built is NEITHER cheap or easy.
Run oil high in ZDDP or add ZDDP to the oil you are running.
Replace $300 cat every 25K if you have one installed.
I'd check the valve clearances anyway.
Significant noise on a build like that would "Dead Line" the engine for me.
No more operation until noise issue diagnosed/fixed.
Too loose makes noise...
Too tight eats wallet and time...
Death is silent here.
Gotta have a cat unfortunately, but I could care less about replacing them every 25k.
Got it. I'll give a call to a shop I seriously respect on Monday and have them take a look.
This is an important tip!
Rip your valve cover off and check valve clearance YOURSELF! if you haven't already.
Shim under bucket (best IMO) takes a real competent technician to get right.
You yourself are MOST LIKELY more competent than the head shop.
There are very very FEW machine shops that are really competent.
They exist but it's 1/50 in my experience.
Machine shops usually try to hit a "range" around a specific target clearance.
Commonly the range is +/- .002 so a total range of .004
When I'm setting up an appliance car, lots of everyday Toyotas and Korea cars have SUB or SIB (shim IS bucket), I'll try to hit +/- .001 with a total range of .002.
For something like you have there (world class stuff) I'll try to hit +/- .0005 with a total range of .001.
This is a PIA but worth it in the long run.
If your valve adjustments are all over the place then your cam timing events are also all over the place. You can have significantly different compression readings with a range of .004. It doesn't matter on an appliance car with wimpy duration numbers.
It WILL matter on a 400+ HP BP build with nice cams.
You need to EITHER be a freaking Wizard at cutting the valves to hit the shims that came in the kit OR (far more common) have a bunch of the shims for your set up in different thicknesses...
Another way to "skin the cat" is to start with shims that are too thick and grind the shims INDIVIDUALLY on a little surface grinder. This works great (+/- .0005 is EASY) and may be what your head shop did.
The OEM seem to love specing shim diameters different than each other so having a bunch of working shims is rare unless...
Mazdas are what you do. Like Super Miata. I'd bet they have a shim box for SUB stuff, a fairly heavy box with lots of different thicknesses.
I'm currently building a 2UZ V8 Toyota 32 valve engine. I'm working with a new machine shop but he's used to doing Korean stuff which requires very expensive buckets to adjust clearance. He cuts the valves to hit proper clearance with the buckets that came in with the head.
He is the first machinist I've worked with that I think has a chance to hit it right but the juries still out until I bolt the heads on and check clearances myself. I'm hopeful as the freaking shims themselves are $15 each!
He goes +/- .002 normally.
He tried to hit +/- .0005 for me.
If he did he will get fully assembled heads from me and I'll let him do everything from now on.
I haven't taken assembled heads to ANY machine shop in 2 decades...
The 2UZs were fully dissembled when I took them to him.
But it's super easy to verify you're fine or you're screwed.
Just check your valve adjustment yourself...
Mr Ninja, you sir are a rare perfectionist in the auto mechanics field. I'm sure your paying customers greatly appreciate that quality.
BTW, only set lash with head onto block. Doing it on the bench will end in tears.
I could be wrong on this but I believe metal core cats stand up to zinc better than OEM ceramic cats.
Yep, agree 100% on the bolt head on BEFORE.
I very interested if my new guy can pull off the impossible and hit the numbers.
Here's the real KICKER. He did it WITHOUT the springs holding the valves in place...
Juries out but I'm hopeful. He does a bunch of stuff that requires competence.
I've never encountered a cat that died early due to ZDDP.
American cats die early (100K), Japanese cats seem to live forever 3-500K
I'm seeing more and more engines damaged (mildly) by lack of ZDDP.
Even wimpy stock spring 4 valve junk, super mild cams and baby springs suffering scuff damage.
Big cams and especially "heavy doubles" require increased scuff resistance, full speed ahead with cat killing additives, and automatic replacement of the cat early.
I'm fine with using cats on my stuff but I will not shortchange an engine to make their life easier.
Nice to hear about heavy metal cats being more tolerant, Thanks Emilio...
Yep, agree 100% on the bolt head on BEFORE.
I very interested if my new guy can pull off the impossible and hit the numbers.
Here's the real KICKER. He did it WITHOUT the springs holding the valves in place...
Juries out but I'm hopeful. He does a bunch of stuff that requires competence.
I've never encountered a cat that died early due to ZDDP.
American cats die early (100K), Japanese cats seem to live forever 3-500K
I'm seeing more and more engines damaged (mildly) by lack of ZDDP.
Even wimpy stock spring 4 valve junk, super mild cams and baby springs suffering scuff damage.
Big cams and especially "heavy doubles" require increased scuff resistance, full speed ahead with cat killing additives, and automatic replacement of the cat early.
I'm fine with using cats on my stuff but I will not shortchange an engine to make their life easier.
Nice to hear about heavy metal cats being more tolerant, Thanks Emilio...
One disquieting thing I ran across...
I needed a couple of Toyota shims for a 4 runner I did a while back and I "tooled up".
I took a couple of dozen kolaches and donuts to my local Toyota dealer and offered them up sacrificially.
I WANTED in to their mechanics "shim box". Every dealer I have worked for has had one.
The service manager told me "We don't have one, we don't adjust valves, we just wait until there is a problem and replace the heads or the engine, Most of the time it's a whole engine and we make more money that way".
Holy sheep **** Batman!
When you no longer do shim style valve adjustments you no longer need that level of technician...
This is the FUTURE gentlemen.
Get used to it.
You all are better than the local dealer wrench...
Last edited by technicalninja; 02-21-2021 at 08:08 PM.
Reason: of changed to or, bigtime different meaning
I use Lunati's stuff but any cam manufacture stuff will probably be fine.
Amsoil makes a dedicated race oil with excessive ZDDP. That's what I would spec for your car Virant.
Where do you live? Update your profile. I wanted to know this to determine your level of emissions enforcement at your loaction.
If you're in California you have an uphill battle.
Wyoming, Texas, or Florida not so much...
No emissions where I am at. And if they decide to start trying to enforce them, I own a lake cabin that I can register it at that will never have emissions.
Ditch the cat...
Better yet, put that kitty up in storage for when it becomes a problem.
Replace with "test pipe" with matching flanges to the cat so change out is a 10 minute proposition...
On a 2003 if you have any visual emissions inspection you will need both the cat and a down stream O2 sensor to appear compliant.
It doesn't usually mean they have to actually work, they just have to be on the car.
Full OBD2 emissions means the upstream and down stream O2s have to work and the cat has to pass an "effective" test called a "monitor".
I don't think your car could pass a full OBD2 test and I have no idea what ECU you are running right now.
Only way to skin the full OBD2 test is with a piggy-backed ECU with the stock ECU still doing it's monitor tests.
It's one of the reasons I moved to Hood County. No OBD2 at all. I was in Tarrant and screwed for doing anything to 96 and newer vehicles.
If I do it for myself, misdemeanor, if I do it for a customer.
Federal Felony...
There is multiple reasons I operated an automotive air conditioning shop. This is one of them.
I like doing stuff, I just don't want to go to Federal prison for it.
02-20-2021, 11:25 PM
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