Mazda in Ford clothing: '85 Laser TX3, 4WD turbo glass gearbox wonder

[Abarth]

From the picture of your turbo it looks like the actuator itself could be too small and not strong enough to hold the wastegate shut under boost.

Ive just put a T25/60 turbo in my Punto GT and have used the old T2 actuator. Im getting the same type of problem, even with it free boosting it will only get to .9 bar. I have spare S15 actuator that is physically a lot bigger than my T2 one which is simular size to yours. Im yet to try it but im pretty sure thats the problem.

[0R10N]

the wastegate actuator that's currently being used is the exact same actuator that was on my VF8 hybrid (i.e. the standard Mazda one), I simply swapped it over when the new turbo was assembled. The general rule with these hybrids is that you do not use the Subaru actuators, otherwise weird boost issues occur.

Similarly, the exhaust side of the turbo is the standard Mazda 12R one. The only difference being that on the VF8 the wastegate port and flap were standard, and on the VF10 the wastegate port and flap have been enlarged.

It is a mystery, but given that's the ONLY change which has taken place, it's gotta be a flow related issue. I wish I knew more about turbos to be able to tell for sure.

I took the valve completely out of the boost tap over the weekend and coaxed 0.9 bar out of it. So adjustment is still possible, it just needs to be more (less?) precise.

Oh well. At least it still cleans up well for photos!

[Abarth]

Yeah im thinking the the actuator isnt holding the wastegate flap shut when it starts to get on boost. It would take more tension to hold shut a ported flap and a standard one.

On my Punto im going to clamp the wastegate flap shut with a spring to temporarily make sure its shut then take the car for a spin. If it makes good boost then will know its the wastegate actuator causing the problem.

[0R10N]

hmm that's a good idea actually, pity my actuator is impossible to get to with the turbo in situ (it's literally nestled right up against the block).

I did pull the wastegate line off a few weeks back and drove up grafton gully to see what the boost would do, managed to get to 1.1 bar (the limit of the old tune) on half throttle before I backed off. Think I got to about 4000rpm in 3rd gear.

[mixmasterlex]

On my Punto

Going to need a project thread for this/sorry for hijack

[keltik]

Smaller exhaust wheel will be causing greater exhaust gas backpressure. That pressure acting over a larger surface area from the ported wastegate will put a much greater force on the actuator than what the previous turbo probably did.

Seems like an easy fix.

[0R10N]

285,590km: SPEEDO CABLE SNAP

Replaced it with the one out of the BFMR project car, hopefully I can find another one before it goes back on the road. I'm glad they're 2 piece and only the lower section had snapped, as trying to feed the entire thing up into the back of the dash would have been interesting.

Damn old cars!

[ryanfels]

2 piece. Never heard of such a thing

[0R10N]

yeah a few of the Mazdas run a setup like this. but others like my RX-7 and FWD TX3 track car use a completely different (single piece) speedo cable setup.

technically it's three piece if you count the fitting that sits inside the top of the gearbox

[0R10N]

So thread necro for Spence and I to talk shop.

 

Basically in the last 22 months I've done nothing with this car, except to blow it up Lost compression on cyl 1, think it's cracked a ring.

To be honest it's been rather tired up until now, first signs of anything going wrong was when it started boosting only 0.7 bar regardless of whether the wastegate hose was connected or not (see above weirdness), then it started eating a million litres of oil, now it has zero power and coughs and farts and smokes and misfires all the time. Poor thing.

Gonna see if I can get away with a bore and hone of the existing block and fit 0.5mm oversize gubbins, possibly forged internals depending on whether I bother chasing more power with a retune. Managed to get the below quote for a rebuild utilizing regular cast items.

 

225+ boring Cs polish 50+ oversized pistons gaskets rings bearings and gasket set 745+ For a total of 1173 including. Plus fitting and removal and assembly which is prob about 10-12 hrs so another 1k

 

...maybe a bit on the cheap side, given the amount of work required?

[Spencer]

Alright found this thread! Yea that quote is way cheap man, I know you CBF but you should look into taking it out yourself, you can run the whole rebuild a lot better if you drop the engine off at the machinist of your choice, all these workshops will just farm out the rebuild anyway.

 

Anyway does that quote say $225 for a crank polish and bore? man you will spend close to $200 on getting it sonic checked, measured up and hot tanked. At 300 thousand Kms you have to factor in the crank may need a grind, the mains may need a hone, you will want to do the valve seats/recon the head etc. I think 2.5k for machining and parts would be reasonable if you take the engine out and dictate what machine work you want done.

 

So yea pull it yourself, its a weekend's work max and will be fun with some loud musics and beers.

[Yowzer]

I like pulling engines. If you need a crane or anything I'd be keen to come help tear it out.

[0R10N]

After working on my other BFMR I swore never to fuck around with transverse 4WD ever again but that's only because the engine had to come out and go back in four times. With a bit of help I guess I could be persuaded to pull the engine on this myself (especially if it saves me a heap of coin).

Yeah Spence that quote is borderline illegible but the machine shop is supposed to be fairly reputable (Papakura Engine Specialists).

Good point on the crank - Thomas managed to source a brand new genuine crank for Dave from Mazda Japan, maybe I should do that?

I will talk to my mate Andy this weekend for another opinion, his old man owns Papakura Mechanical and he used to have a TX3 like mine - incidentally I think they use Papakura Engine Specialists as well for their rebuild work.

[Spencer]

I wouldn't go thinking about what you need to buy parts wise until you have the block and crank measured up, may be as simple as oversize bearings and a grind, I don't know what bearings are available though. Just figure out what piston and bearing oversize options you have and then get the bottom end measured and go from there thats pretty much it man. Only parts you should start ordering now is gasket sets, and consumables like water pumps, cam belts etc.

[Dell'orto]

Remove engine, put on pallet, send to us, win. Quote doesn't really seem to allow for cleaning time either? Ultra cheap quote!

Spencer - don't think you'd need to sonic check a B6 block, they aren't that thin? .020 overbore won't hurt it.

[flyingbrick]

I like pulling engines. If you need a crane or anything I'd be keen to come help tear it out.

My gems engine is ready... What day you free?

[0R10N]

I wouldn't go thinking about what you need to buy parts wise until you have the block and crank measured up, may be as simple as oversize bearings and a grind, I don't know what bearings are available though. Just figure out what piston and bearing oversize options you have and then get the bottom end measured and go from there thats pretty much it man. Only parts you should start ordering now is gasket sets, and consumables like water pumps, cam belts etc.

Sweet. Pull the engine, do stripdown and inspection then go from there sounds like a good plan. Have to wait for at least one of my cars to sell first before doing any serious work anyway (and see what's left over from dropping a chunk of coin on the mortgage)

A lot of B6 internal bits are still available new (aftermarket and genuine) because of the MX-5 brigade which is handy. Already got a mate from BNT pricing up consumables plus a new clutch because I'm pretty sure the original is ruined after nearly 300k.

[Spencer]

Remove engine, put on pallet, send to us, win. Quote doesn't really seem to allow for cleaning time either? Ultra cheap quote!

Spencer - don't think you'd need to sonic check a B6 block, they aren't that thin? .020 overbore won't hurt it.

Do this, grotty is the man and I'm sure would look after you. And yes if it's never had a overbore no point in a sonic check.

[0R10N]

Sold the AW11 (reluctantly) and made it rain down at my mate Andy's workshop. Consensus was close to Spence's theory above, so I left it in his capable hands. (and yes the $1173 quote would have been far too low for what eventually ensued).

 

Two months later...

 

Verdict: all oil rings completely busted plus two cracked piston rings. 8 of 8 exhaust valves burnt, guides and seals also toast. Basically, it has been crapping compression and oil out the exhaust for god knows how many km, this was also why it struggled to make any more than 0.7 bar boost. Unlucky!

 

But it wasn't a turbo issue, which was good.

 

 

Currently the Link has a less than optimal tune on it, since I took this opportunity to upgrade the fueling system to 510cc Evo injectors with Walbro 255 pump and a better fuel pressure regulator. Alienprobe made sure to adjust the fuel and ignition maps prior to moving it out of the workshop to ensure it wasn't running too lean (or way too rich as turned out to be the obvious case). I'm still taking it easy during the run-in period regardless.

 

The old tune netted 143kW so it'll be interesting to see what power figures await after a complete teardown and rebuild. Again I'm mindful of the gearbox exploding so I'll have to draw the line somewhere around 160-170kW.

 

Got the car back so did some minor tidying up today, finally fitted the Cusco strut brace I bought from Yahoo almost two years ago and swapped over the Omori gauges from the track car (which will be getting some Prosports if I ever find the energy to resurrect it).

 

 

 

Conveniently the parts car in the picture above had rear trim panels that were already modified (i.e. had cutouts) for a strut brace. But discovered I had to remove the rear seat side trims as well (and swap over the bolsters), which added a good hour to the whole exercise!

 

 

 

 

With the parcel tray back in place you can't even see it. Will probably take it for another drive this evening and run it in for another few kms, see if I notice any difference in handling/chassis feel with the strut brace fitted.

[HighLUX]

Plz do some helis