RS Aizawa ITB 1.6 - valve stem seals - improvements while in the head ?

So my white car, which, I promise I will do a walk around one day soon, has developed what is probably a valve stem leak (or, rings, but not likely)

When giving it the full monty between 6K and 8K, it smokes grey-blue when I lift off until it drops under 5K or so. All that vacuum. I've put in some seal conditioner and it has reduced to the smoke but not solved it permanently.

I've done an ATF soak (24h) of the piston rings in situ while hand cranking her. The rings I suspect to be perfectly fine. There's barely any blowby on cold idle either. I checked by blocking all but one breather. (NOTE: they weren't, it was probably the oil control rings that were gone, which I fixed separately through multi-day ring soaks)

This is one of those cars where, I really want to retain the character of the 1.6 and especially the 1.6 RSA ITBs / value therein - the car is an absolute blast on this intake setup and so that's the one thing I won't change, so I've no interest in going 1.8. It'd destroy the intrinsic value and nature of the car.

So... what to do ? Let's OVERTHINK this! :-)

Sourcing Seals. - I'd either get the OEM Mazda ones or a set of supermiata viton ones. Or are there better available than those ?

Since I'll be going into the head there's an opportunity to improve things. 8K rpm is probably not ideal with HLAs I'm eager to take it from HLA to SUB. It works fine now but I'd like to let it go a little higher and get there a little faster.

Sourcing SUBs - Probably want to get the mazdaspeed SUB lifters and then source / machine the lashcaps in europe (good supply of 6mm ones here) - has anyone got better suggestions ?

But there's opportunity to do more.

Valve springs and Retainers - to go past 8K and get there faster - All the google searches I do for valve springs kind of.. well, they're not really informative. and they're really old.

I see supertech have lovely kits. I have my doubts about supertech ones (actually, I have my doubts about supertech anything..) - are they OK ? But I'd love to lose more weight in the head - Supertech's TI retainers look unique and interesting. Thinking to combine those and some volvo or 'race engine' ones I can perhaps find from the EU mx5 tuning wasteland.. or from Japan ? But from who ?

Or should I forget about messing with the springs/retainers and just do the SUB conversion after replacing the seals ?

Not trying to save money, just want to get the best out of my 1.6 and do it the 'best' way and let it safely go over 8K. Arguably I should get everything from Japan (Maruha and the rest) but I'd rather get the unique things from there. Lashcaps aren't unique. etc.

All criticism welcome and insights gratefully received.

I think you are spot on in everything. I would (will) use OEM Mazda seals, but I know from a good friend that Supermiata ones are also decent, he has had no issue with them so far.

SUB's, take a look at Hyundai/Kia part no 22226 2B401 (or any number after B for that matter); they are identical to the Mazdaspeed ones, but easier to source in Europe and slightly cheaper.

Regarding valve springs, I would also upgrade since you are in there. I have the following data points:

OEM Mazda (NA8) [BP05-12-125] - 275lb/in
OEM Mazda VVT In - 235lb/in
OEM Mazda VVT Ex [BP2Y-12-125A] - 194lb/in
Sealed Power VS-949 - 283lb/in
Sealed Power VS-855 - 349lb/in
Brian Crower BC1600-1 (orange dots) - 237lb/in
Piper Cams VSSVTR2 - 276lb/in
PAC S90015 - 216lb/in

I have no data on the NA6 springs though. Please note that some of the above are not meant for B6/BP engines, but are close enough in dimensions. Let me know if you need more data, I have a spreadsheet with dimensions, block heights, seat pressures vs seat height etc.

So, here's the deal. I understand what you want to do, end goal, but I think you're leaving a lot on the table and I don't know the specs of your engine as it currently sits. If what I write below is redundant to what you already have, please forgive me.

If you want to spin the engine to 8k, springs will be needed. If you plan for the engine to live at those revs, you are probably going to need to consider more than upgrading the valvetrain.

In regards to valve stem seals (VSS), my first thought is OEM. Why not vinton? I had heard some brands were not lasting. It has been a few years, so double check that. Maybe it's installation, maybe a manufacturing defect, but OEM or OEM-quality hold up pretty well.

Valve springs (VS), retainers, seats, keepers, etc., yes Supertech are very good and for us here in the US, easy to get our hands on. Super rare JDM (y0!) stuff is neat, but I don't like paying a premium for similar stuff that would be very hard or impossible to replace if things went pear-shaped. If you plan to just take the revs up, a single spring is fine, if you plan on staying at 8k for extended periods, dual-springs should be considered. Also, factor in the possibility of whether or not you will playing with camshafts. Lift plays a big part in how much cam you can play with and the OEM valve springs don't have a lot of head room.

If you are planning on VSS and valve train upgrades, plan on pulling the head. Don't waste your time on trying to do this with the head still in the car. Why? Because that is where you are leaving a lot on the table for these types of performance upgrades:

Shave the head. I'm not talking about a re-surfacing, I'm talking about a compression bump. .025-.035" (.6-.9 mm), maybe more if you have the support. This is probably the easiest HP upgrade for the expense.

Replace the valve guides. You could go through all this work replacing the valve train and seals only to find out your valve guides are too loose. You will have the same issues you have now in short order, or little to no change.

Port the head - mild or wild, depending on your budget improving the air flow through porting, gasket matching, deshrouding, etc is a solid upgrade.

Valve seats - don't know how well your engine has lived, but without removing the head, there are many things you won't correct. New valve seats, machining the valve heads, can not only help sealing, but improve airflow. You *could* consider going to oversized valves in this route too.

Head studs - I'm a big proponent of switching from TTY head bolts to studs. Better clamping, reusable, better resistance to lifting, etc. It's a pretty inexpensive upgrade for durability and other power-adding options down the road.

At some point, you need to also consider for all this added zing (revs), what can your stock connecting rods handle? The loads on the rods reciprocating that fast are enormous.

The biggest question though, is where you want to stop is up to you, all this above are diminishing returns.

Quote:

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Originally Posted by kung fu jesus

what's on the table

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I've read what you wrote a few times KFJ :)

I absolutely agree with the head off thing - there's a lot that can be done and... I'm if it all goes to plan I'll have the budget to do go overkill with a forged bottom end.

Valve guides are probably buggered and should be replaced since that's path the oil takes past the VSS.

State of the engine it has probably been given a mild shave but internals are stock bar the cams, which are RSA's regrinds. I'd like to try to stick with those but I know I should go higher lift/duration for ultimate performance.

124HP at the wheels. this graph shows the difference with (green) or without (red) the 50mm intake spacers, both with the ITG filter on top of the 50mm trumpets. Also this has a ceramic coated Maxim Works header.

https://trull.org/alex/media/pics/ca...0mmspacers.jpg

My instinct tells me to stick with single valve springs. FM have a kit with ti retainers that's single spring and they claim it's good for 9K RPM. https://www.flyinmiata.com/default/v...tml#additional - is this just the ST kit relabeled ? :D

also I understand the NB valve keepers/collets are lighter weight than the NA ones ?

The bottom end thoughts are a lot simpler than the top end strangely..

Pretty much set on Carillo H beams, and sorely tempted by the nutty 80.5mm Mahle/Maruha pistons (3mm between cylinders), but I think some 79.5MM wossners (leaving 5mm between cylinders) would be better for block longevity/stronks. These are my paper calculations. I haven't measured an actual block.

I don't know if 1.8 VT components are lighter. I do know the 1.6 stuff has more specific orientations and placement. I also don't know if the FM stuff is ST, but it wouldn't surprise me.

Cams get tricky because I don't know the current specs on the regrinds and there is a fine line between drive-ability and performance if you start getting aggressive.

On the bottom, look into King racing main bearings or similar. I would be considering uprated con rod and main cap hardware (ARP) for "cheap" insurance.

I don't like a 3mm spacing on a 1.6, it's too fragile at that point for as high as you want to spin it. I wouldn't expect it to last long.

You should get solid numbers, like leakdown and compression before you start doing any of these repairs and upgrades. It's really useful data and helps you see where you have come from.

FWIW, my rebuilt 1.6 was built to survive track and street in pretty warm climates. After the rebuild and break in, I saw 210 PSI across the cylinders. Stock is about 190-195. The head was a mild port with gasket matching. I used a new OEM 1.8 BP oil pump shimmed because I had the long nose crank.

If you are going high RPMs, you are going to want to consider a blueprinted oil pump from Boundary. Those OEM pump gears aren't fond of those speeds for long.

LNC here too and already on a fluidampr. My oil pressure is quite good on this car but agree it's worth going boundary. The sender kind of gives up signaling properly at WOT over 7K but as soon as I come off the throttle at high rpm it shows the true pressure which remains good.

I had the same issue.

I've started buying all the bits to make a go of this..

Kind of doing a '1.5' job. I think the compression on this engine is good so I'd rather not touch the cylinders unless I have to.

So '1.5' means .. Not going to take the head off. Not going to change from the RSA regrinds cams.

Will be going lightweight everywhere I can change though :D

SUB & Solid lifters, Light Cam Gears, New valve springs add Ti retainers, and obviously... new seals.

We'll see!

Aftermarket springs on a budget: https://bofiracing.co.uk/valves/upgr...da-mx-5-na-nb/

Using the Volvo springs was initially discovered by someone on that mean turbo site years ago and is a tried and true option on a budget.

Valve stem seals are done. Along with the supertech spring kit. Installing the collets was interesting. FM tools are really good.

I measured up the cams that were in the car and they appear to be absolutely stock measurement. So several friends one of whom will probably end up tuning the car, have suggested 272 duration 9mm option.

Currently awaiting a delivery estimate from TODA on said cams.

And for your bizarre random facts book, here's a keeper (heh)

Also I can confirm now that the NB keepers/collets weigh approximately .06 grams more than NA ones....

0.69G - NA keeper
0.75G - NB keeper

I weighed four at a time to get this number. heh.

I always use a small, slightly magnetic flat screwdriver with a dab of grease to do collets. Once I feel the shoulder slip into the relief on the valve stem, I go to the next. The grease helps hold the collets to the screwdriver blade, and adhere them to the valve stem until you release the compressor. Valvetrain work is rhythmic.

Quote:

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Originally Posted by kung fu jesus

I always use a small, slightly magnetic flat screwdriver with a dab of grease to do collets. Once I feel the shoulder slip into the relief on the valve stem, I go to the next. The grease helps hold the collets to the screwdriver blade, and adhere them to the valve stem until you release the compressor. Valvetrain work is rhythmic.

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Aye. I was really enjoying it once I got into it. I ended up using a some thin tipped tweezers and grease. I didn't have a screwdriver with quite the right level of magnetism (it was too stronk).

Same. Valvetrain work can be very zen and enjoyable. It’s rewarding fitting all the precision components together.

I would love to experience this someday as well. But i think i would like to work on an engine with someone that knows what they are doing :).

Quote:

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Originally Posted by Willywongka

I would love to experience this someday as well. But i think i would like to work on an engine with someone that knows what they are doing :).

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I watched so many instructional youtube vids I wrote my own process on what to do as an aid to mind. I'd been prepping to do this work one way or another (psychologically or making queries with suppliers) since I wrote the original post.

I was going to ask someone else to do this for me but I realised it didn't make sense - I had the tools, I had the time, and leaving the car in a profit-making garage for up to a month wasn't something I wanted to do since I they'd just want to put it all back together ASAP but I wanted to research the parts I wanted and take my time.

Probably the biggest needs for doing valvetrain stuff is a spring compressor, a clean work surface, abundant lighting, and organizers, cups, or trays to keep components together.

The first time I did a head reassembly was at a kitchen table. It surprised me how smoothly everything fit together.

272 9mm Lift I/E cams from Toda arrive this coming new week.

Should be rowdy but still streetable. What engine management are you using? Plans for indexing?

Quote:

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Originally Posted by kung fu jesus

Should be rowdy but still streetable. What engine management are you using? Plans for indexing?

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Currently: ME221
Link G4X is waiting here in the box, though :-)

Indexing is on the cards. I've got the Maruha adjustable gears.

There's also a Finnish chap who published a goldmine of research on this subject... with the same spec cams.

https://mymazdamx-5.blogspot.com/201...specs-and.html

Cams on Insta

They're in and spinning freely :D

Wouldn't want to run much more lift on this head without relieving the exit and entry path around the bucket orifices.

I've measured the gap without any shims in yet so I know what to order.

Those boring numbers are over @ http://www.mighty5s.com/thread/964/a...b-built-thread :D

The good news is that the gaps (minus the 0.2 or 0.25 mm lash spec) are all OVER 1mm so I can easily order the lash caps without worrying about grinding them down.

Just wanted to say that dealing with Cat Cams directly in Europe is a pleasure.

I've been doing the lash adjustment and I've two 'direct' specs to work with:

Toda's spec from the cam spec sheet:
IN: 0.20mm
EX: 0.25mm

Mazda's NB2 Solid spec per
IN: 0.21±0.03 mm
EX: 0.31±0.03 mm

( https://trull.org/~alex/pubmirror/ww...e_overhaul.pdf )

As such I've got the intake valves to 0.19 or 0.20mm - and I'm really happy with that.

I'm now redoing up the exhaust valve setup since one was a bit tighter than it ought to be. 0.24mm on one valve - the rest were 0.26. To address the 0.24mm I'll end up taking it closer to the range of the Mazda spec. And I'll treat the Toda 0.25mm as the safe minimum. But for exhaust this seems sensible.

Lash Caps - Tip of the Valve Stem or Tip of the Bucket Post ? Well now...

Supermiata and/or Bill@MiataRoadster suggested the best way to go with the MMD buckets was with 6mm supertech lash caps upside down, the post of the bucket being 5.57mm but I ordered lashcaps from Cat Cams, which only have a 2.5mm skirt and it turns out that with the NB keepers in for the supertech TI retainers, there's legitimately enough clearance to install the lash caps 'normally' on the valve tip. 3.1mm of clearance between tip and top of the keepers with 2.5mm of skirt on the lash caps. Seems the better way to do it. Also no more lash cap randomly pulling out with the bucket, or weird greased lash cap installs.

I'll get to the intake cam, invert the caps, .. measure clearance all over again, and then retime her ,etc.

My only real opponents are wind, rain and time. Mostly wind though.

On a side note..

In my research on valve stems and temperature/expansion coefficients and other similar engines I've found loads of different specs. here are some interesting ones:

A 4age spec that was I: 0.15-0.25mm E 0.20mm-0.30mm - but the valves of the 4age are a bit shorter than the B6 or BP.
zz2 have very similar valve lengths to the B6/BP (5mm difference max) and I: 0.08-0.18mm and E: 0.22-0.32mm specified.

Effectively, the shorter the valve stem the tighter the clearance can be, but it mostly matters for the exhaust side.

It runs!

https://www.instagram.com/p/CXMBSu7AVGP/

Let the fuel pump run to cycle out the old fuel from the lines.

Plugged the laptop in to get a log.

This was one of the quickest startups I ever had with the car.

No Smoking. Not noisy. Rich Cold Startup as usual.

At the end I let it idle without any throttle for one minute and it was happy to sit at 1100 with 14 AFR.

I've ordered some new cam belt covers and idlers to address an issue with the front (the belt seems to be coming too far forward and the old covers look rough)

News on this.

The VE table tuning is now in its 8th iteration.

I've been to 7800 RPM now in the map. It's pulling golden. The 7K+ region is less mushy with the solid lifters in. Even with a load of ign adv removed it's fun up there.

Now to circle back to the original smoking problem. Evidently, it wasn't valve seals but rather piston rings. But as of today's tuning and thrashing session I may have actually cured it. I can't quite believe I have. But my car just stopped smoking out the rear as of the last 10 pulls of the run. It's been using less and less oil each day I've run it.

Multi-day Method documented here: https://mighty5s.com/thread/3918/smo...le-stuck-rings

You might have actually cured it. I have experienced instances when this has been cured by hard running an engine in a small motorbike; piston rings need pressure to properly seat.

Quote:

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Originally Posted by HarryB

You might have actually cured it. I have experienced instances when this has been cured by hard running an engine in a small motorbike; piston rings need pressure to properly seat.

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I'm about to get it back from the body shop and I'm re-visiting this now.

looking at a more aggressive process, after doing some research and thinking. wishful thinking ? perhaps. I'm ready to try some things.

Get the cylinders to the point of the start of the compression stroke - so we can build pressure in the cylinder.

take a mixture of acetone and toluene/xylene (both are in gasoline as octane boosters, and they are in universal disolvent/synthetic paint thinners)

first let it soak a bit, then force the mixture past the rings using pressure. [ a modified compression tester hose and attach that to a pressure source (er... tyre pressure pump!) ]

keep forcing fresh mixture past the rings so that whatever varnish/deposits are really and ideally liquified and ready to be ejected...

put in fresh thicker oil (5w50? 10w50?) with a small % of kerosene and naptha .. effectively, MMO or redex. - thicker oil to maintain a sensible weight and lubrication.

go out and drive it, quite hard. at one point in december/november I nearly thought I had it sussed as it wasn't smoking at all on over run coming down from 8k, but it didn't last heh. and then the sheep got me.

I think I'll need to extend the hard driving part. Maybe take it somewhere fun. I've got plenty of hills to do that with.

p.s. yes, I know I'll need to be careful with these chemicals. my health and all that new paint lol.

And the bottom end bearings too; they need proper lubrication.

^ Thanks for the reminder Harry

I'm planning on not rotating the engine significantly while I do this, as I don't want any of this mix coming through the oil pump.

I'll get the chamber to the compression phase and then put it in 5th / handbrake up.

I'll finish each cylinder with a teaspoon of real oil to bore before letting the engine turn.

Have you scoped the bores?

Also are you running a catch can? I have used cans to monitor blowby. Sometimes the PVC system just doesn’t work like it should and can offer paths to diagnosis.

Driving in heavy vacuum can help free the rings after your treatment.

I've done the soak twice now, once for 8 hours, a 2nd time for 24 hours. I've got a borescope so I will have a go.

there is no PCV anymore - I've configured a draft tube arrangement - filter on the exhaust side, 'pcv valve' is a straight barb fitting to the catch can and the catch can vents to a draft tube, there's a wee bit of oil at the bottom of the catch tank - and it's working.

I checked the cold idle blowby and it doesn't seem excessive, but I need to compare with my turbo car which has PCV, really.

Next step is to get the cylinders leakdown tested.

Goodness.

Checking leakdown and bores would have provided more info to troubleshoot initially.

Good luck!

The compression and performance seem to be good but I want some numbers 'so I know'. I've got the ITV/MOT test tomorrow. Once that's over I'll head over to a shop that might do the test.

Passed the test, 2nd time. After some frustration with the fact that it has a 'new' license plate but it's a 1992 car. Cat tests are only required on 1995 and later here.

On the smoke front. I've seen nothing for the last week. More driving required.

Passed the test, 2nd time. After some frustration with the fact that it has a 'new' license plate but it's a 1992 car. Cat tests are only required on 1995 and later here, but the people running the test centre get confused.

On the smoke front. I've seen nothing for the last week. More driving required.

So this is a very late follow-up but I thought it worth mentioning.. I moved to a thicker oil - 10w50 and that solved most of the smoking issue but I could still, let's say, 'provoke it' ;)

After having seen some higher oil temperatures (on the motorway) now I had some data collection in place for that (bosch combo sensors wired up to the link g4x) - a few days ago I switched to a higher flowing thermostat (Made in USA, 160f 72c) - and that dropped my coolant and oil temps both by around 20c - coming from max 126c to max 106c oil and from 100c coolant to 80c coolant.

Result - 40kpa more oil pressure minimum, sometimes more, and I can't get it to dump smoke on over-run at high revs - thinking being the higher temps were causing the rings to lose tension.

RS Delta is now asking me to do a video.. so, one day.. one day! I feel a bit more tempted now.