also I've witnessed an oil pump explode at 7500 after being fine for years at sub7

 

Did that engine have a harmonic damper? Any more info? Very curious!

 

Ok so here are a few common KNOWN failure points:

Throttle body shaft/screws
Valve damage from spinning too high with stock valve springs

So if you upgrade the throttle body and valvetrain, what's next?

 

No, it was a stock 94 engine. On a couple of our 01+ vvt engines that were revved out to 7500 we had valve seats that were pounded in pretty hard. also stock engines

 

Just to be sure, you're saying was a stock engine that had the factory harmonic damper installed, right?

I think I'm going to at least check the valve lash on my VVT head. I set all the valves to exactly minimum spec when I built it, it's got 700 miles and a lot of 8 to 8,800 pulls on it, so I'm curious to see if it tightened up after that abuse.

 

correct. completely oem long block

 

I know it's not much, but you all have convinced me to lower my hard limit to 7,400, 7,200rpm soft limit.

 

What's the longevity like with the BPs that had a factory 7500rpm limit?

 

That's a good question. I know at the very least they have a few interesting little tid-bits that US cars don't: like a balancer thingie on the throttle body.
And I guess they have the old school bp05 head with hydro lifters?

 

If you have to change any of the shims, aim for the maximum tolerance this time. My engine went from all intake valves at .009 and all were under that, one of which was .004. But thats a motor thats built and spent a lot of time above the stock redline. Jury is still out on my bearing wear, motor is still new enough that blackstone couldnt say conclusively if the motor was in the final stages of break in or if it was wearing quickly. When I do my next analysis in June it'll be more conclusive.

 

As far as i know, i thought they had 4W heads? BP5A?

 

Great question actually! Actually I can add to that, were they 7,500 indicated or actually 7,500? Like how U.S. shows 7,200 but it's really 6,900.

 

Yeah if they are tightening I'll shoot for looser! Kinda curious now what they are. I did all the machine work so I'm hoping I did a good job! My seat widths were .060 and I cut them so the seal towards the outer edge of the face for more size/area.

 

US hard limit is not 6900.

I'll be able to answer that question in a couple weeks, though.

 

Interesting, so what is the factory U.S. rev limit? I thought it was 6,900 fuel cut on my 99.

 

Apologies if i'm wrong, but i'm pretty sure it was 7200, as the cluster indicates. Cluster being in accurate, though, you'll see 7500-7600 on the factory tach. (I saw about this during one of the burnouts on the way home with the new purple car.)

 

We discussed jdm engines recently, I'm looking for the stupid thread can't find it. But yeah I thought they were 4w's too but someone said no. Rev? Ben? One of the aussies? Someone

 

I mean... they kindof have to be. Or at least have solid lifters, because BP5A cam.

I would have literally thought it was the same head package we got on the MSM.

 

You're more than welcome to prove me wrong. I don't think we have too many discussions about it so I'm sure others will benefit. I'm just repeating what others posted. I don't know much if anything about the JDM-Tyte motors. I was surprised too

 

I'm just musing out loud. HLA vs. SLA cam profiles and all that. The cam is used in SLA head.

After seeing what Mazda did with some of the later KLs, i don't think i'd be surprised in the slightest if they used a shitty old BP05 head with SLAs and better cams because reasons.