For Sale NZ 2.7 litre stroker motors

[6A13TT TYPE S]

Well I've been doing some planning and I've come up with a plan to do stroker engines.

Offset grinding a stock crank to give 3mm extra stroke combined with nissan conrods and toyota pistons gives you 2.6L

Or if you go 1mm oversize pistons 2.66L dispacement is possible

Rods would cost about 900

Pistons will be between 600 and 700

Stroking the crank will be around 500

Then you have all the usual costs of engine builds

Rings, bearings, gaskets, seals boring, honing etc etc.

I am yet to test the block for stroker clearance to make sure the rod isn't going to hit the inside of the crankcase.

But its looking like a real possibility and do able for about the same price as what it would cost to build a regular forged stock stroke engine rods and pistons are cheaper but they require machine time to fit correctly onto the crank.

If anyone is keen let me know. I will probably build a motor for myself and sell on my already built engine which is in my white legnum to fund this but it could be a possibility for me to sell off the shelf forged stroker motors in the future if there is enough intrest in this

 

[twisted32]

Oh stop giving me ways to spend money Adam, I already have enough....

 

[jungle]

I considered offset grind also when I built my 6A back in 2010. But as time was limited I did a standard rebuild.

 

[6A13TT TYPE S]

Yeah just and Idea I had after looking at a busted 6A crank ontop of the scrap bin all week. Plus stroking the crank will make the big ends a much more common bearing size making it easier to get parts for.
Just need to offset grind the buggerd crank and get a hold of a rod to check crankcase and girdle clearance with the extra stroke and the fatter rod.

 

[lateshow]

Would 3mm extra stroke improve power delivery on low rpm? Like stroker evos which have far less turbo lag than for instance my car right now

 

[6A13TT TYPE S]

Thats exactly it. Its only 166 cc bigger but every little bit helps

 

[6A13TT TYPE S]

Machined a Nissan conrod today, narrowed the big end to fit the crank and rebushed the small end to suit the toyota wrist pin.

As you can see even the stock nissan rod is considerably beefier.

And then I put it in a block to test it for crank case clearance. Theres plenty of room to swing the rod around without hitting the inside of the block but as you can see from the above photos the toyota piston has a longer skirt in the piston and this fouls on the crank counterweight but thats easy to alter.

With the crank wound to TDC the piston sits exactly 1.5mm down the bore which perfectly allows for 3mm extra stroke on the crank to give perfect deck height.

Was hard to video and turn the crank at the same time but you get the idea.

 

[pretzil]

Wow, that is beefier, what nissan is it out of btw?

 

[smohekey]

Moist.

 

[jungle]

Great work, looks like a goer!
Can you guys shot peen rods?

 

[6A13TT TYPE S]

Yeah next step is to get a crank ground.

Pistons are going to be cheap if we stick to the OE Toyota ones which unfortunatly aren't available in 82mm. Only 81.5mm which results 2630cc instead of 2660cc but given a set of 6 brand new 81.5mm toyota forged pistons is around the 600 dollar mark. I can live without the extra 30cc considering aftermarket pistons like CP or wiseco will cost twice that.

The perks of using the toyota piston is it is available with 2 different dish volumes. The big dish gives about 8.3:1 comp ratio about stock and the smaller dish gives about 9.2:1 which would be great foe people running flex fuel. You could easy get that up to 10:1 or above by milling the heads down a bit.

We dont shotpeen in house but can get it done, however the nissan rods have plentiful aftermarket support so just buying a set of Eagles would do the job nicely. I just used a stock rod to test because I had one in the shed.

 

[jungle]

Ah nice about the Rod's then! Timing is shit. Would have loved to do it to my current engine. But I'm on a strict time scale. Easy to adapt to another engine though!
81.5 should be plenty bore. Great news with the different dish though. The ability to go 9.2 is fantastic!

 

[mookers]

Dumb question - the thread title says "stroker" but when you're talking about 81.5 vs 82 mm piston diameter, does this mean you'd have to bore the cylinders out as well? What's the stock diameter?

 

[smohekey]

Stock is 81 from memory, so there is slight boring, but probably a good idea in any case.

 

[6A13TT TYPE S]

Yes stock bore is 81mm. Going to 81.5 or 82mm only gives you 30cc or 60cc extra displacement respectively.

The main point of this is stroking the crank which gains you just over 100cc even on stock bore size.
They are a 51mm big end journal stock which is quite large. By using the nissan rod which is designed for a 48mm crank pin you can grind 3mm off the diameter of the big end journal on the crank. But by grinding all of the material off the inside of the journal you are effectivly moving the Centerpoint of the big end journal 1.5mm further outwards. Meaning at TDC the piston is pushed 1.5mm further up and at BDC it oulls the piston 1.5mm further down. This is your 3mm extra stroke
Because the pistons is being pushed up an extra 1.5mm you need a 1.5mm shorter rod to stop the piston being pushed 1.5mm out of the top of the block and hitting the head. This is where the nissan/toyota rod/pison combo comes from the nissan rod is 2.5mm shorter that stock and the toyota piston is 1mm taller in the compression height which results in a overall 1.5mm shorter combo which is perfect to stroke the crank 3mm and have the piston exactly flush with the top of the deck.

I initially thought of using 1mm oversize pistons with the stroker crank to get 2,660cc but toyota dont sell the pistons in +1mm (82mm).
They only sell them in +0.5mm (81.5mm)which gets you 2,630cc
you could used secind hand stock bore 81mm toyota pistons which will give you 2,598cc but when installing forged pistons its common practice to go 0.5mm oversize which allows you yo machine the blores to attain the correct piston to bore clearances, as forged pistons have a different expansion rate than cast pistons.

As said above you could get aftermarkek 1mm oversize pistons but that would cost you more than double what toyota charge. The only advantage there is aftermarket pistons could be ordered with less dish for much higher compression but you could also attain this my skimming the fuck out of the heads therefore reducing the combustiom chamber volume.

 

[mookers]

Stock is 81 from memory, so there is slight boring

I don't find this thread even slightly boring...

 

[smohekey]

I don't find this thread even slightly boring...

Damnit, stupid puns is my job!

 

[6A13TT TYPE S]

Damnit, stupid puns is my job!

Scott, king of the shitposting

 

[6A13TT TYPE S]

Dropped a crank off to get ground on friday. Then I can recheck the crankcase clearance.

 

[smohekey]

Much anticipation. Such baited breath.