My "L29" build.

[jonbills]

Thanks John, the pistons & chambers all look similar, no real signs of detonation - no pitting to surfaces of chambers or pistons. I think the notorious poor flow on #6 has something to do with it, but not sure whether my cooling mod made it worse. It also just occurred to me that I was running straight water (& steel seal) at the time which won't have helped cooling.
It did go nice before it died though!

It took me quite a while to get round to stripping it down because I'd already started rebuilding my MR2 engine. Finished that up last weekend, so back to the Z!

 

[tel240z]

Hmm very strange Jon must be 5 or 6 years since i built my engine and have used it hard around track and drag, only cooling mod i done was an extra water tank mounted higher than the rad and head plumbed into the cooling system

 

[jonbills]

Yep. Often fiddling only causes problems. Luckily Mr Mori is happy to sell single pistons so that and a good hone should sort it out.
Still got to get to the bottom of why the compression is low though.

 

[jonbills]

A little update: I've ordered the necessary parts to repair from Kameari & Rockauto. (new piston, ring set, snaprings, conversion set, bearings, oil pump) .

I think we're concluding the root cause was a couple of things:
1) the piston to bore tolerance was 0.07mm. That's within the Kameari spec but other reading suggests it's tight. So the blocks going to get a parallel hone anyway, and with luck it'll clean up by 0.09 and that'll be good.
2) The holes in the rod bearing that provide oil to the rod squirt holes didn't line up well (because of using aftermarket rods). Although I did drill them wider to have a couple of mm overlap, maybe it's not good enough - with the new ones, the bearings will be redrilled to have exactly the right holes.
3) the diameter of the squirt hole exit in the rod is a lot bigger than that of the stock rods. It seems quite likely that at low revs with 5w30 oil the oil pressure isn't high enough to spray the underside of the piston with oil. So in the rebuild I'll be adding turbo oil pump and will probably swap to 5w40 oil.

 

[Rob Gaskin]

Jon, I used 10w60 in my trackday car.

 

[jonbills]

Which 10w60 did you use Rob?

 

[jonbills]

At long last, my replacement piston has arrived from Japan

All considered, with changes in exchange rate and rape by parcelforce, this one piston and ringset cost 2/3 what the full set of 6 cost 18 months ago.

The block has cleaned up nicely, now with 0.1mm piston clearance (up from 0.07) which will be fine.

So I just need to wait for my replacement replacement rod bearings before I can start building.
First replacement bearings turned out to be aluminium, which apparently isn't good enough. New ones will be steel/copper/lead.

 

[jonbills]

Bottom end is back together at last.
Bearings made of the right stuff, holes in the right place, bores a bit bigger, bigger oil pump. It'll work longer this time I hope.

 

[jonbills]

Heads back on. Work stopped temporarily to go in search of a new torque wrench!

Any recommendations? Halfords, Teng, Sealey look like the options.

 

[Rob Gaskin]

Is that a Stillson on the cam?

 

[jonbills]

Is that a Stillson on the cam?

Yeah Wickes' finest
It's on the flats between two lobes jammed against a head bolt.
It's as good a way as any to hold the cam to torque the sprocket bolt.
I was adjusting the torque wrench to 105 lb-ft for it when it broke.

Sorted now and cam timing set. I've also sorted out the extra water outlets at #5 and #6 to return to the thermostat housing rather than pump inlet this time.

 

[jonbills]

Also did a trial fit today of the lovely Zstory exhaust with the Nissan comp type inlet manifold and the plumbing.

It had to have a little ground off the flange to clear the inlet manifold.

And a little bit off the inside of the flange on each port to match the outline of the exhaust ports on the head. (Not surprising since the ports have been enlarged a bit).

With a little luck should get it all fitted tomorrow and maybe break it in on Monday. Yay.

 

[candy red]

Well done John looking good look forward to going for a spin :lol:

Derrick

 

[jonbills]

Thanks Derrick.
I did manage to get the engine installed but it took until 9 this evening.
I lost a fair bit of time cutting manifold studs and washers and making shims to bolt the manifolds down.

And then I wasted a bunch of time putting the fly wheel and clutch on and getting it in the engine bay before I realised I'd forgotten to put that plate behind the flywheel. Grrr. Whats that plate called?
And then I put the engine mounts on the wrong way round and for some reason really struggled to get it to engage with the gearbox.


Still on track to run it tomorrow though!

 

[candy red]

Don't worry John we've all done things twice for one reason or another well done for sticking at it good job your calm by nature.

Derrick

 

[jonbills]

Don't worry John we've all done things twice for one reason or another well done for sticking at it good job your calm by nature.



Derrick

aren't we due some updates on your 260 Derrick?

 

[johnymd]

Looking forward to seeing it performing Jon. What's your plans for this year? Drag, track, or just road?

 

[jonbills]

There'll definitely be some drag racing to see what it'll do and because it makes a good value day out.
I'll also aim to get some track time at a japfest or two. Normal year then

 

[jonbills]

Still not running . The exhaust manifold is touching the passenger footwell. I spent a couple of hours hitting it with a hammer and then gave up.

 

[candy red]

Thought it was meant to bolt straight on John wheres the problem the manifold or the footwell?