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-   -   Anyone interested in built heads? (https://www.miataturbo.net/miata-parts-sale-trade-5/anyone-interested-built-heads-42885/)

rider384 01-12-2010 10:39 PM

Anyone interested in built heads?
 
I was thinking about this today.

By "built", I mean +1mm valve job, integral cams (duration/lift is up to buyer), stronger valve springs and a port and polish.

I may sound a bit of an idiot, and people will obviously want proof that I know what I'm doing and that they're worth it, I figure I can have one built by next summer to bolt on, dyno prove, and run it for a couple thousand miles to prove that it'll hold up.

Price would be around 1,400-1,500 dollars and would take about a month to build.

Given that I could prove it over the test of time and on the dyno, would anyone be interested in purchasing one?

jtothawhat 01-12-2010 10:45 PM

Seems like a good price, how much for cams alone?

SKMetalworks 01-12-2010 10:46 PM

6 months is a long time to wait for a customer. What would be the turnaround time from deposit to ship out?

rider384 01-12-2010 10:48 PM


Originally Posted by SKMetalworks (Post 507576)
6 months is a long time to wait for a customer. What would be the turnaround time from deposit to ship out?

I won't be accepting orders until I know that they're proven and that they're worth making for my asking price. I'm still very early on, just planning everything out and seeing if there's a market for these.

If and when I decide to start making these it would be about a month to a month and a half, simply because the cams take 3-4 weeks to be ground.

rider384 01-12-2010 10:48 PM


Originally Posted by jtothawhat (Post 507575)
Seems like a good price, how much for cams alone?

Cams are 725 a pair strait from Integral.

JasonC SBB 01-13-2010 12:15 AM

Custom cams are like $450 at www.elgincams.com
He makes you fill out a form and asks for flow numbers if you have them.

Duckie_uk 01-13-2010 06:19 AM

Are these regrinds or do you have to provide a blank for him to work on?

gospeed81 01-13-2010 07:24 AM

I'm interested, but without custom cams or +1 valves.

I simply want stronger valve springs and (possibly solid) lifters, as well as a badass port and polish...purpose being to support a slightly higher redline without power dropping off. Not shooting for the moon...just don't want power to taper off before normal redline.

EDIT: btw, this would be for a 1.6L head if it makes a difference. I recently saw the HKS 1.6 cams go for a about $350, and if it came time for cams would likely go that route before a custom grind. I don't see a huge reason to go for cams on a turbo car for my goals, and would definitely forgo it if it drastically dropped the price.

JasonC SBB 01-13-2010 10:30 AM

Duckie Elgin's charge is for regrinds on stock cams so he makes the base circle smaller.
I had him do my 97 M3 with hydraulic lifters and gains were very noticeable.
I haven't asked him about what supporting mods are needed on a 99+ head (i.e. need thicker shim, does it need shim under bucket to do that).

gospeed81, the tapering off of torque is a function of the cams, less so of lack of head flow. You need a later closing intake valve - either with more duration, or by retarding the intake some.

Re: slightly higher redline - Rebello Racing tell me on a 99+ that the springs can be shimmed up a little bit to support a slightly higher redline.

gospeed81 01-13-2010 10:36 AM


Originally Posted by JasonC SBB (Post 507692)

gospeed81, the tapering off of torque is a function of the cams, less so of lack of head flow. You need a later closing intake valve - either with more duration, or by retarding the intake some.

Forgot to mention I already have FM cam gear and plan on about 4* retard on the intake cam....but will dyno tune to perfection since I plan on a port and polish anyhow.

I've heard (recently here) that the +1 valves make less of a gain than a good P&P...and have heard elsewhere to forego cams and keep it simple on a head build. I'm hoping getting rid of the overlap will change the characteristics enough for my liking...but you know what they say about things you've heard and not researched enough.

JasonC SBB 01-13-2010 11:02 AM

It's not the reduction in overlap that increases torque near redline, it is the later closing intake. If you want a later closing intake without decreasing overlap, you need more duration.

Between increasing duration and simply retarding the intake, more duration is more beneficial for a high revving motor.

However because you have cam gears already you should try the retardation first. You can measure the effect without a dyno by logging AFR's on back to back street runs to high RPM on the same stretch of road, at different cam gear settings. e.g. a 4% increase in AFR at 6800 RPM pretty much means a 4% increase in torque at 6800 RPM.

On the 99+ Rebello told me +1 on the intake requires lots of extra work to make it flow. The exhaust doesn't require much work. And yes there are more gains just from the porting than +1 + porting. Dunno about the 1.6.

Duckie_uk 01-13-2010 11:06 AM


Originally Posted by JasonC SBB (Post 507692)
Duckie Elgin's charge is for regrinds on stock cams so he makes the base circle smaller.

I would imagine that just changing the profile would cause minimal change in the base circle that could be compensated with a slightly thicker shim. If you wanted to go for high lift then the shim would be impractically thick and not only increase the mass of the valve train but also run the risk of flying out I expect.


Originally Posted by JasonC SBB (Post 507692)
Re: slightly higher redline - Rebello Racing tell me on a 99+ that the springs can be shimmed up a little bit to support a slightly higher redline.

The springs from the 94-97 head are slightly stiffer than the springs from the 99+. So putting 94 springs in your 99 head with the lighter solid lifters should support a slightly higher redline. Anything more than 1k rpm and you need shim under bucket and preferably double valve springs.

94blackmx5 01-13-2010 11:16 AM

there will be a lot of interested people, you will need to come up with a list of options and prices


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