Thread: cheap stroker option

Right so I just thought I’d share another option for a sr20 stroker. I haven’t done it i’ve just done the numbers so it should work. Obviously if you were going to go this route you’d need to talk it over more seriously with your engine builder.
Its not for everyone as it requires a change of rods and pistons But if your opening up your motor for a hi performance rebuild in may be worth it for you.
So as you guys all know sr crank is 86mm stroke and 51mm Big Ends. Sr rods are 136.25 long and sr pistons have a compression height of 32mm and 22mm little ends
Now for a “cheap” off the shelve 2.1 stroker with a minimum of machining.
Starting with a Standard SR crank Get a machine shop to offset grind your BE’s down to 48mm, This is a 3mm change in BE size so will give you an increase in stroke of 1.5mm, now 87.5mm stroke. I’m unsure of machining prices over your side of the world but at a guess i’d say somewhere around the $300-$400 mark (USD)
The reason for changing to 48mm BE (other than to increase stroke ) is to now make the use of b18C rods possible. B18C rods are 138mm long = 1.75mm longer than sr rods. The other nice thing about using b18c rods is we all know how cheap honduh parts are.
So we now need to match a piston.

So SR piston compression height = 32mm
32mm-1.5mm (change in stroke) – 1.75 (difference in rod length) = 28.75 Piston Compression height
Ford 2L duratec pistons are std bore 87.5mm and are also available in 88 and i think 88.5mm (87.5mm is probably really the max limit on stock liners, your call though) with a compression height of 28.65mm and a pin dia of 21mm same as the Honda rods, so no modifications that end. They also have 35mm intake valves (unsure on exhaust size) So valve cut outs shouldn’t be a problem either. They are also available in CR from 8:1 all the way up to 14:1 (CR’s are based on the standard duratec, I currently don’t have enough info on the duratec to work out what compression ratio’s would be when using these pistons in this motor configuration)

So 87.5mm bore 87.5mm stroke gives a capacity of 2105cc. With a rod stroke ratio of 1.577 vs a standard sr’s 1.584.

So its more or less a bolt a bolt together package, the only potential issue is the b18c rods have a big end width of 21.77mm vs the sr’s 22.71mm. So some trickery would be required there but thats not really a big deal.

Its really only a cheap option for a bit more capacity if you were looking at rebuilding and were going after market rods and pistons anyway. Although I see no reason why oem parts couldn’t be used if you could source the parts. Whether its worth it to you is another story.

Anyway just thought i’d throw it out there for everyone.

Thanks for the info. If you can get a hookup on machine work this seems like a cool option, however you can snag darton sleeves and install them for around 600 dollars, and that gets you 2188cc's with 90mm bore, and 2287cc's with 92mm bore.

Yeah, I'm pretty sure the machining work could be had for around the $500 mark. I didn't realise that darton sleeves could be had for so cheap though. I always thought they were over $1000.
its just another option I guess. Just a bit cheaper than buying a stroker crank

sleeves plus instal is about $1000

I would just sleeve a block and go 90mm pistons for 2.185

LOL You're so funny and you've just won yourself a darwin award!!!

Really? Mazworx has the sleeves listed for 375 and labor for 280.

Well if you think that is so call them.

Here is the phone number 407-281-1223.

Ask for Mark, then say I have a SR20VE block and would like to buy some sleeves and have them installed and deck the block. Get back to me on the price since you know so much, I bet it is even more than a grand maybe closer to $1200-$1300.

do it.

Really!!!!!

From what you've seen is there any issues with92mm. Or anything to worrow about vs going 90mm?

Just do a 90 and be happy

Nick m your awesome.. nice work. Hopefully some will use this and take advantage