Suggestions on engine work - NA8

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3gress
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Re: Suggestions on engine work - NA8

Postby 3gress » Sat Feb 23, 2019 2:40 am

For comparison's sake, I bought a pair of toda camshafts from project.r a few years back, Solid lifter type 256* 9mm.
With jenvey itbs, a bit of headwork etc, the engine made good power and could breathe well past rev limit.
Now with more compression, upgraded valvetrain and head work the engine is crying out for a little more lift and duration to help it breathe.
I am now looking at the 272* maruha cams to gain a little more power for a lot of money spent...hindsight value $$?
Picking a cam that gives upper rev limit power without sacrificing torque lower down in the rev range is a bit of a balancing act when trying to maintain street manners.
If you go too large a duration you will move the power higher up and need to rev it hard all over the neighbourhood . Not the most desirable thing with the jenveys barking for attention already. You get stuck with a car that doesn't make the power in the rev range you're most likely to use.
It sounds like what you first suggested would see you achieve reasonable power gains for reasonable costs without losing street-ability or having to start forking out for upgrades like springs, lifters, shims and labour costs etc.
If likely to become a naturally aspirated power chasing addict regardless of compromise, look toward the larger solid lifter cams at least. :twisted:

manga_blue
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Re: Suggestions on engine work - NA8

Postby manga_blue » Sat Feb 23, 2019 8:54 am

I had in a set of Maruha F-cams/Tomei Poncams (same thing) in my NA8 for a while. F-cams provided a moderate boost to power throughout the range and mush more freedom at the top end without sacrificing any flexibility at the bottom end. They're the cams Mazda should have put in the car in the first place.

They were a genuine straight bolt in using the original ECU and lifters. They work best as part of a matched set of mods: mild head porting, good exhaust system, cold air intake, new ECU, sports clutch. Then you get a genuine sports car with a very willing free spinning motor. Mine was pulling around 85rwkw with a 7600 redline and was a joy to drive like that.

The only issue that I had with those cams was that they probably put too much stress on old worn HLAs. They had to be replaced as a set to make the motor useable above 6000.
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Re: Suggestions on engine work - NA8

Postby lucmor444 » Sun Feb 24, 2019 11:16 am

I am not chasing any significant power gains (just some more would be nice).

At this stage I’ll chat to a couple of local shops about a cam regrind to see if this suitable over the Maruha F-cams.

I’ll also start considering a BP4W head but I expect if I went down that path that would be a fair way off.

How worn could I expect HLAs to be on a car with 125Ks on the clock?

Thanks again to all who are contributing to this thread.

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Re: Suggestions on engine work - NA8

Postby project.r.racing » Sun Feb 24, 2019 6:59 pm

IF you ain't chasing a big power gain. Then go with your original plaN OF A BOLT IN AND PLAY SET OF CAMS.

I only said what I said as I have never heard someone before with an aftermarket ECU and quads hint at a mild upgrade in power.

But if you are happy with a mild jump in power. Go the original Maruhas you were thinking of. No need for head removal or extra parts, (except a cam cover gasket). And you'd do the job in under two hours.

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Re: Suggestions on engine work - NA8

Postby lucmor444 » Sun Feb 24, 2019 7:09 pm

All good project.r.racing. I just thought about this further and recognised that I personally am not seeking big power gains. I will still explore the local options however and who knows how they may influence me!

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Re: Suggestions on engine work - NA8

Postby manga_blue » Mon Feb 25, 2019 5:06 pm

lucmor444 wrote:How worn could I expect HLAs to be on a car with 125Ks on the clock?

There aren't many NA8s running around any more with only 125Ks on them. :beer:

If it's had regular servicing, especially if that included full synthetic, they should be good to go. Really the HLA problems only start to appear after around 160Ks unless someone let nasty old dino oil sludge up inside.
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Re: Suggestions on engine work - NA8

Postby hks_kansei » Mon Feb 25, 2019 5:24 pm

if you're concerned, HLAs are only about $8 from memory, and really simple to change if the cams are already out.


Otherwise, there's other things you can do with them to clean/maintain them, in order of effectiveness and ease (and cost):

- Use an oil flush every couple of oil changes (it's basically diesel, but I find it helps wash out the HLAs and slows down the clogging process)
- remove HLAs and soak them in kerosine etc, and by hand pump them to rinse out gunk
- remove HLAs, disassemble each HLA and manually clean the internals then reassemble


Also note that if you remove the HLAs and clean them out (by whichever method) make sure to prime them before reinstalling them.
Priming is as simple as submerging them fully in some engine oil and allowing the inner cavities of the HLA to pre-fill.
This means that on the first engine start after reassembly they dont need to wait as long to pump up, so you're not slamming fresh cam lobes with clearances way off what you want.
1999 Mazda MX5 - 1989 Honda CT110 (for sale) - 1994 Mazda 626 wagon (GF's)

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Re: Suggestions on engine work - NA8

Postby manga_blue » Mon Feb 25, 2019 5:32 pm

What a lot of guys do when they're putting lower base circle diameter cams in with HLAs is reshape or chamfer the oil feeder holes into the lifters. Basically the HLA gets reloaded with oil while the HLA is in the non-lift position (which is most of its cycle) and the oil loader groove of the HLA sits over its oil feeder hole in the head. With a lower BCD the HLA sits a little higher at rest, doesn't get as long an oil feeding period on each cycle and can become starved of oil, especially at high revs.

You can use a fine sharp knife and very small round file to cut and shape a chamfer groove up from the outlet of the hole a further 1.5 mm up the bore to cover the new, higher position of the HLA. Take great care not to scratch or damage any other part of the HLA bore in the head, just the area immediately around or below the outlet holes. Keep all debris out of the holes.

Here's a photo from old fried head of mine. Those two little round oiler holes you see now each have an extra 1.5mm in radius towards the top. Ignore the crap in it, it's been sitting out in the weather for a couple of years.

IMG_20190225_172333022.jpg
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Re: Suggestions on engine work - NA8

Postby lucmor444 » Mon Feb 25, 2019 8:59 pm

Thx manga_blue - I have been studying up on HLAs and cleaning them etc so I reckon I will do that regardless of the lower Ks on my car.

Something new for me about the tip on the feeder hole - would you have to take the head off to ensure no debris gets down them or is it about just taking it slowly and carefully etc?

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Re: Suggestions on engine work - NA8

Postby manga_blue » Mon Feb 25, 2019 9:39 pm

You can do the oiler holes with the head on, just need to be super careful about debris. Plug them with something you can withdraw later and seal them off with grease.

I've cleaned a few sets of HLAs. It's been a failure every time. No matter how careful and meticulous I was there were always one or two lifters damaged by the cleaning. Once you have 1 or 2 damaged HLAs in the car then they're impossible to find and you have to replace the full set. The older the HLAs the more chance there is of damaging them. I suspect that when they get a bit worn they develop a bit of a lip somewhere in the internal pistons. Knocking them apart drags the lip down the internal bore and f**ks the HLA.

My advice is to either leave them alone or buy a full new set. Given that your car has only 125Ks then I'd say leave them alone. It's also impossible to diagnose bad HLAs when they're out of the car too. Each HLA feels different because the amount of oil retained in each one differs. If an HLA feels much spongier than the rest then it's because they happen to have less oil at the time - that's all.

A final word of warning about re-installing them. If you pump them full of oil first you'll find most of the valves are stuck open when you bolt the cams down. That's OK, just leave it overnight before starting. The oil will slowly squeeze out and the valves will shut. Otherwise it may start and only run on 2 or 3 cylinders and you'll panic thinking you've screwed something up.

Don't ask me how I know all this.
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Re: Suggestions on engine work - NA8

Postby lucmor444 » Mon Feb 25, 2019 10:25 pm

Thx again manga_blue - sharing your experience (however gained!) is much appreciated.

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Re: Suggestions on engine work - NA8

Postby lonesailor » Fri Mar 22, 2019 10:46 am

Someone was suggesting dismantling HLA's to clean them out, if you do be very careful ,there is a tiny spring inside which is very hard to see and they are easy to reassemble incorrectly. Ask me how I know!

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hks_kansei
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Re: Suggestions on engine work - NA8

Postby hks_kansei » Fri Mar 22, 2019 11:05 am

lonesailor wrote:Someone was suggesting dismantling HLA's to clean them out, if you do be very careful ,there is a tiny spring inside which is very hard to see and they are easy to reassemble incorrectly. Ask me how I know!


yeah, tbh it's probably a lot easier to do the lazy clean method and just soak them in kero for a few hours, then try and give them a few pumps and back in the kero.
1999 Mazda MX5 - 1989 Honda CT110 (for sale) - 1994 Mazda 626 wagon (GF's)

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Re: Suggestions on engine work - NA8

Postby project.r.racing » Fri Mar 22, 2019 12:42 pm

I would agree. A 90-95% clean HLA is better than a dirty one. And you have spent zero time and effort pulling one apart.

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Re: Suggestions on engine work - NA8

Postby lucmor444 » Fri Mar 22, 2019 2:12 pm

And a new set of HLAs aren't that cheap (and they are no longer available through Mazda) so the quick clean method sounds reasonable.


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