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Post by swordspork on Jan 23, 2021 18:06:44 GMT
Didn't have much time today but worked on the head a little. I got my valve spring compressor so will set to work on changing out the valve stem seals. A nice surprise here shows the valve guide has a bronze liner insert.  |
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Post by swordspork on Jan 30, 2021 17:48:41 GMT
I've now finished installing the Mazda valve stem seals.
I did a fair bit of reading on these seals and it seems that if your going to replace worn/ non-genuine seals with anything other than the genuine parts don't bother because they'll leak.
The Mazda seals are different parts for inlet and exhaust. Most oe seals appear to be the same part for both.
The exhaust are green and inlet are dark grey. Both are manufactured by NOK in Japan.
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Post by swordspork on Feb 16, 2021 7:45:04 GMT
Someone asked for pictures of the ports. So here they are. Would be good to compare with ported examples. That stuff on the valve stem is grease. The guys that did the check and rebuild used rather a lot. A friend of mine that has ported a few heads (a series engines) was very impressed with the quality of the stock Mazda ports.   |
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Post by lowender on Feb 16, 2021 10:17:29 GMT
Would be good to compare with ported examples. Blink stage one:  |
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Post by Zed. on Feb 16, 2021 11:30:06 GMT
Someone asked for pictures of the ports. So here they are. Would be good to compare with ported examples Thankyou  so their insistance (on website) about choosing better flowing castings looks reasonable as theres lttle visable re-shaping.. ^^to get around race rules re. blueprinting / modifications maybe? you don't see many properly / professionally modified ports / heads for the mx5 engines, partly due to race regs & partly due to cost vs. gains, FI can supply more power as a cheaper & almost 'bolt-on' mod. I've spoken to a few friends & tuners that ran dyno tests (when Mx5's were new) showing little gain for just headwork  although the standard manifolding / cams / compression were retained so limiting the gains  iirc, they suggested that the small exhaust ports & manifolding were the biggest restriction. A friend of mine that has ported a few heads (a series engines) was very impressed with the quality of the stock Mazda ports. I don't think you can compare an A series port design (dating to the 1950's  ) - especially the siameese'd inlet (that threadded between a pair of pushrod-tubes!) with the B6's from the 80's  I find it amusing that the B6 head / ports get slated by keyboard warriors - especially the fb experts as being a bad design & terrible for flow compared to the 1.8 examples  B6 inlet has straighter port thats angled at the valves unlike 1.8's (even the later mk2 1.8 heads) and admittedly there is a restriction / narrowing near the ports devide to each valve but as a standard port it's not bad at all. exhaust is a different matter, all harks back to the turbo design & development so is a small port to promote high velocity (get the turbo spinning earlier, great on lower revving road engines)a friend had a Mazda 323 turbo 4x4 rallycar, as a restricted power engine (had the msa's turbo inlet size restrction) it produced 175hp @wheels but that was with 'group A' cams and other work - doesn't sound great but that turbo restrictor plays havoc with engine power  I'm experementing with how much reshaping & enlargement a B6 exhaust port can take without revealing the coolant passageways (OR the oil gallery below cams!), anyone got a scrap 1.6 head Interesting 1.6 fact. the valve stems are 6mm diameter, the 1.8 has 7mm diameter so Mazda made efforts to help airflow & valvetrain wieght on 1.6 / B6 engines then reverted back to roadcar spec. for the 1.8........... Rich. |
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Post by swordspork on Feb 16, 2021 13:15:47 GMT
Someone asked for pictures of the ports. So here they are. Would be good to compare with ported examples Thankyou so their insistance (on website) about choosing better flowing castings looks reasonable as theres lttle visable re-shaping.. ^^to get around race rules re. blueprinting / modifications maybe? you don't see many properly / professionally modified ports / heads for the mx5 engines, partly due to race regs & partly due to cost vs. gains, FI can supply more power as a cheaper & almost 'bolt-on' mod. Yes as I understand it with the 'race' heads there is more emphasis on choosing a "good"v example initially as the rules do not permit porting. Interestingly the website has updated and there is slightly more explanation on what is done to get the performance - I think on the 1.6 heads the flow is improved mostly by the 3 angle valve seats. Porting on top of this does improve things further but not as significantly. This is certainly not a route you would go if your main concern is BHP gain/£ spent it would lose out massively to FI. I do think there are nice gains that can be had by combining Bolt-ons, headwork and a mappable ecu. I reckon I was around 130 ish at the fly (105 at the wheels on skuzzles dyno) with just bolt on exhaust mods. I do think it possible to see around 145 ish at the fly with headwork perhaps a little more depending on supporting mods. I do say this with no in depth history on the current head - A few years back I compression tested it and all cylinders were around 220psi - so maybe its been skimmed, who knows. Greg on car passion channel recently released a video focussing on bolt on mods - IIRC he went from 112bhp to 136bhp just with an exhaust and intake on a 1.8 with an me221 - (this is with US fuel too). I believe he plans release another video looking at further mods. That is interesting - especially as the stem seals are the same for 1.6 and 1.8 - I'm no expert but you'd think they would need to be different if sizes aren't the same. |
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Post by Zed. on Feb 16, 2021 15:18:45 GMT
Interesting 1.6 fact. the valve stems are 6mm diameter, the 1.8 has 7mm diameter so Mazda made efforts to help airflow & valvetrain wieght on 1.6 / B6 engines then reverted back to roadcar spec. for the 1.8........... That is interesting - especially as the stem seals are the same for 1.6 and 1.8 - I'm no expert but you'd think they would need to be different if sizes aren't the same. Guess I'm off to measure...... what have I crossed wires about then... Rich. |
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Post by Zed. on Feb 16, 2021 15:38:30 GMT
That is interesting - especially as the stem seals are the same for 1.6 and 1.8 - I'm no expert but you'd think they would need to be different if sizes aren't the same. Guess I'm off to measure...... what have I crossed wires about then... Rich. Okey... it's raining, I'm Lazy & in the house....  ![]() have a copy of Mazda's workshop manual for the 323 1.6L Turbo 4x4 etc.  B6T engine, predessesor of the Mx5's B6ZE(RS) engine..  I've photographed these 2 pages as theres good info  so ~6mm stem does this mean I've got to strip a 1.8 engine to measure ^^I'm actually interested in this & any other info that can be ound / shared Rich. |
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Post by swordspork on Feb 16, 2021 16:22:29 GMT
Interesting attention to detail in that manual.
No wonder these engines are rather robust.
IIRC I found sources maybe flyin miata....suggesting early 1.6 heads needed to use all exhaust stem seals rather than inlet and exhaust. Presumably to account for the difference in diameter?
At any rate, autolink, bofi, mx5parts etc. All suggest that the inlet and exhaust seals are the same for 1.6 and 1.8 from 89 to 05.
Having installed them recently, everything fit snugly so perhaps the difference in valve stem diameter doesn't matter in this regard.
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Post by Zed. on Feb 16, 2021 17:00:10 GMT
I'm having a dig / trawl to find info, unfortunately the Mazda manual pre-dates the 1.8 so has no dimensions... I refuse to open haynes....  I've also seen mention of different inlet & exhaust seals.... hummmmmmmm... Rich. |
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Post by swordspork on Feb 16, 2021 17:58:34 GMT
Yeah it wasn't easy to navigate when sourcing parts. With not much information to go on and no exact data on what year the head is I just went with the advice that was more prevalent.
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Post by dadbif on Feb 16, 2021 22:33:24 GMT
I have an early Autodata in the garage, will have a look tomorrow, but it may be too early for our cars.
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Post by swordspork on Feb 20, 2021 16:43:16 GMT
Installed a roll bar today. It's a mission. Found some rust when I removed the arch liner. Can't say I'm surprised....
I wire brushed it and treated with metalmorphise. Will dinitrol the feck out of it next.
Roll bar looks the business. It's a gc fab gc1 I think. I'll take pictures once everything is back in fully.
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Post by swordspork on Feb 27, 2021 20:06:54 GMT
Roll bar in.  |
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Post by swordspork on Mar 21, 2021 18:04:02 GMT
Took the bumper off to replace with a better condition one from mx5 restorer. As is normally the way things took a lot longer than expected. I thought that as many of the original fittings were missing things would be quick but this was not the case I had to get the vice grips on some absolutely mullered nuts and in normal Mazda fashion I found and treated surface rust on the front cross member? I'm using metalmorphosis at the moment seems very similar to rc900 for much cheaper. New (to me) bumper is not yet on as I still need to transfer some fittings and badging from the old one. Here is where I am at. Treated and primed the front end. Removal of the end plate things gives good access to the chassis legs. I sprayed in some dinitrol wax with a extension even though they looked fine.    P.s. I don't really care about over spray on the air dam thing lol. |
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although the standard manifolding / cams / compression were retained so limiting the gains 
) - especially the siameese'd inlet (that threadded between a pair of pushrod-tubes!) with the B6's from the 80's 
