Want a "Baller" valvetrain assembly?

I watched the teardown of a Porsche 911RSR engine a few years ago (sorry no pictures), the cam and lifters looked similar to this...



Inverted radius cam profile

[IMG]https://www.miataturbo.net/attachmen...ine=1368049417[/IMG]

Keyed lifters with ramps on the crown.

[IMG]https://www.miataturbo.net/attachmen...ine=1368049417[/IMG]

I swear they must engineer some valve bounce in that thing. How the heck does the valve not launch off that nose?

Bounce would lead to component failure.

They actually lift the valve almost to the point of complete valve spring compression (about .050 clearance). So at max lift the spring physically cannot compress any farther.

Ahh that makes sense. Very cool!

I've got some CatCams here in the UK after contacting them for some clients cars.

I used some of their profiles on a Peugeot 106 I had way back when, it had a decent compression ratio for NA so responded great to a cam upgrade. I'm putting a set of their camshafts in a B6 head for my daily atm along with their own SUBS and spring upgrade. The car currently runs ITB's, long branch primary's and an unrestricted exhaust so hopefully will show a gain!

The specs of the cams are:
- intake: 277°@0.1mm/243°@1.0mm/12.01mm/3.19mm@106°/vc 0.250mm
- exhaust: 269°@0.1mm/235°@1.0mm/11.51mm/2.67mm@-106°/vc 0.250mm

which will hopefully give a bit of a gain on my standard bottom end, I'm planning on running a turbo at a later date so will play with cam timing when the time comes.

I'm lucky enough to have a dyno here on site so will update with some RR graphs on the same setup stock cams vs the above.

Dan

Not true.
Its not unusual for engineers to design a profile coupled with the right valve spring to utilize "valve lofting", in which at a tuned rpm range the valves will "loft" off the profile. Its a way to get variable lift and duration.

It has proven to lead to accelerated wear on the cam and lifters, too much so for OEMs to utilize in street cars, but its plenty reliable for race engines that get torn down frequently.

The lift on those cat cams is really up there, what's the upper limits of a 9:1 block with a 99 head?

Limit for what?
Non-interference
Valve-piston contact at zeroed cam timing
Flow available in a stock head
Reasonable setup with available spring kits
...

11mm starts to be a lot on the BP IMHO (for a number of reasons).
Unsure what clearance there is on a zeroed cam with 9:1 Cast Mazda Pistons on an undecked block.

Exactly. Way too many variables to work with. Some examples that need to be considered:

Lifter bore to camshaft interference.
Reduced based camshafts
Decked heads
Decked blocks
Non OEM pistons
OEM piston design changes. (94 vs 96 vs 99 vs 05)
oversized valves
Cut valve seats

I guess I would say when does the engine become interference? Assuming all else is unchanged from a blueprinted standpoint.

Much more than 9mm lift and you will need to cut the lifter bosses and get springs.

Digging up an old thread I know but those cams I quoted above turned a car with ITB's on a stock head from 100wbhp to 118wbhp with a lovely torque curve. I'm rebuilding the car atm with a VVT engine that will have some custom cams.

Daniel

My intake cam has .495 gross lift. On BP4W head. Im running off the shelf weisco pistons. I had to cut clearance for them to spin. Im running super tech springs with no inner springs.

Stock VVT cams are 9.4mm ;) VVT head castings will take 10mm cams on the intake side, but not on the exhaust side. I seem to remember the 6D castings having more clearance than the 4W castings did on the intake (the exhaust cams are all the same, but 4W lift is only .326 to the 6D's .370), but that might just be in my daydreams.

You don't have to keep the 36mm base circle.
More space for the spring/lash setup is another advantage.

does any one have experience with re-grinds? Before i put my engine into my new chassis I'm going to be replacing the Integrals with something more tame, Im either going to contact Web or Kelford. Im a little skeptical about having web regrind my stock cams vs a new cam from Kelford. But i like the idea of using someone in the US to do my cams so i can stay in contact with them easier.

I will be doing something in the 220 duration @ .050" range and as much lift as i can run with out getting really extreme with the ramps.

Regrinds are much better than they used to be but for me I always order a fresh cam - there's only one argument then if something fails.

where can you find cam blanks for bp4w heads?

I went with cat cams for my custom cams. I can't say enough good things about them. They kept in constant contact with me throughout the whole process and will make you a custom billet cam with whatever possible specs you ask for. Matthew is the guy you want to talk to over there. Great customer service.

You live in the USA? How long did it take to get the cams?

Yes, Texas. Took 2 days to receive the cams once they were shipped from Belgium. Total turn around time of 2 weeks after I placed the order.

I use CatCams too - made from billet. We have our own profiles made to order but they certainly know their stuff over there.

Wow that's what I like to hear,are the prices on these things, my integrals were around $700

Catcams - 1.6, 1.8 And Vvt!!! - Group Buys - MX5Nutz Forum

that's in the UK - I'm not sure what shipping to the USA is like

I had a set of vvt cams custom ground and shipped to me for around 750

Delta Camshaft in Washington is who I use. Great prices, good guys.

$1000 for a set of KL welded cams to my spec.

I run their 272 grind in my daily driver. About $100.

They have BP offerings?

Probably... swear i've seen someone running them.

I think I have heard of 1.6 offerings so it shouldn't be a stretch to do a 1.8. I'll have to inquire.

Even if not... last time I got a quote, it was $50 to measure or set up your specs, $100 a stick to grind. Come up with your own specs, you're talking $300 total.

I want to do cams as well. With the MSM engine, I do believe they come with the solid lifters, no? So, aggressive cams it is! No?

All NBs have solid lifters. Shim-over.

From what I understand though is that you want shim-under, from Mazdaspeed, Mazdaspeed engine should have these then. :P

They should, but they don't.

Exactly, it's garbage. I git pissed when I took apart my engine. Why wouldn't they do that?!
But, so you have shim-under with your 272? I thought you had to upgrade, or is it that you have to have solid lifters?

His 272 cam is in an F2T.

HLAs and a 1.72 rocker ratio, sucker.

Well shit.. we should talk Vlad into testing it out since he should be fairly good at taking out his valve train?

Why would they? The MSM uses the same exhaust cam as every other BP4W/BP6D, and the intake cam isn't significantly more aggressive than any other BP4W cam.

Mazdaspeed and Mazdacomp aren't the same thing.

I thought they were sold as "Mazdaspeed" not comp.
BUT, to run 272 it's suggested to run shim-under correct? Or we can ask Mazda what they did to build the turbo dragster.

I'd convert to shim-under (Or shimless) anytime you're talking about a reground cam. Increasing lift on a ground cam involves decreasing the base circle.

Taking that up involves thicker shims. Thicker shims on a shim-over setup is dildos.

272 is just the duration. Its meaningless.

I assume the MSM was engineered by accountants, not engineers.

Think of it like the RWD Mazdaspeed Protege. Engineered and designed by engineers. Then completely assfucked by accountants.

I thought that was every car.

It is, but it's way worse in the under $30k turbo limited release segment.

There's still some that sneak by. Like the C63 AMG or the Magnum SRT-8. They must have tied up the bean-counters.

I know this. But I'm not going to type out the entire measurements when I can just say 272 and anyone with common knowledge would know your taking about aggressive cams. Unless your taking v8. Then I should just say aggressive cams. My bad.
Meanless, no though, very important.

Turbo= high duration/short lift
N/A= short duration/high lift
Correct? Simplified
Also I like dildos.. but no seriously.
I've looked into cams and have supertek double springs, solid under shim as the setup. Which would be marvelous for 8k red line.

I tend to run them the other way around - big duration (with the right headwork) helps NA engines scavenge well and helps create power.

High lift with shorter duration reduces overlap but allows peak flow figures for a long duration than stock. Perfect for a turbo.

It's really not that simple, anyways.

Next cam for my daily driver will have huge exhaust duration and lift. Short intake duration, big-ish lift.

Indeed, engines are never really simple. Besides No replacement for displacement and Turbo = awesome.

Wait, did I get it backwards?
Is it
Turbo= short duration/high lift
N/A= high duration/short lift

Really depends on the motor. I don't know that turbo BPs like.

I want both high duration and lift on the exhaust of my motor because my combined exhaust valve area is about the size of a mushroom stamp.

I was told
Turbo= high duration/short lift
N/A= short duration/high lift
Talking intake, by a reputable Honda engine builder.

I wonder what it's like for Turbo BP. Anyone have inside on this?

Also, what kind if mushroom stamp? Black? Yellow?

This sounds very wrong. Not to mention oversimplified.

Longer duration is a necessity when an engine is operating at high rpm, regardless of it being naturally or force aspirated. In the case of being supercharged or turbocharged you typically would need less duration to get the same affect because of the positive pressure, but it has a lot more to do with the engines speed than anything. More revs means less time for cylinder filling and evacuation to happen, which means you need more duration.

Lots of duration comes with added effects on valve timing (late intake valve closing in particular) which are often really bad for turbo engines. So if anything I would say that its the exact opposite of what this builder told you.

Turbo cams usually use high lift to get the flow that they cant get from long duration. Ive even heard of people buying turbo specific cam grinds and actually losing peak power because the grind has less duration than stock (with more lift and an advanced intake profile). They gain spool and a lot of mid range, but up at high rpm the cams lowered duration makes the engine run out of breath.

What full tilt said !!!! And let's speak of duration @.05 or 1mm , advertised duration is useless

Maybe it's a Honda thing. Or he was just talking out his ass. He also sarcastically said gridlock with my Wiseco pistons.

Short duration seems more oriented to boosted cars, like you said, since the air is being forced in it should need a long.

So, just run massive duration/lift for ALLOFIT


Ctdrftna, your cans were custom weren't they? Remember the specs?

Mine are the massive/ALLOFIT cams you speak of. The specs are

296(260 something at .05) .495 lift intake
282(250 something at .05) .455 lift exhaust

I will be running different cams when this motor goes into my new car

CT, your cams seem like a good match for my all motor build. we should chat.

you would have had to clearance the head, but did you have any problems with standard valve guides being too long with that much intake lift?

The head is clearanced, I'm running the supertech dual springs without the inner spring, and a .015 shim to get my spring pressure right. I have bronze guides , but I don't think they are any different dimensionally from stock. I know I'm close on retainer to seal clearance. But iv had no problems with these cams.

I did replace a few mazda comp lifters over the winter because they had some funny marks on the top . Looked like the chrome playing came off or something.

The RPM range of those were like 5000-10000 rpm right? It's been awhile since I read the build thread.
I wouldn't mind a max 7200 or 7500 rpm cam.