Short Stroke - Project - Dyno-tastic
Turbo Mini Forums

Hi all,

So after always wanting a 1071, I came across a SA short stroke crank, for a very cheap price.... I just couldn't resist it.

Now I think as its as is a Small Bore, its acceptable for my car :)

Anyway I wanted to complete this project for a reasonable amount of dosh, and those 1275 engines are going for such a massive amount of cash. I stumbled on a freshly bored auto engine on ebay for £50....

I found a thread in Aus that showed the Auto to manual upgrade and I ordered an adaptor plate, and I started some pistol drill engineering....

So I pulled this out as it has holes in it:



Bolted this on




Time for the super long drill and some pistol drill action...

Edited by gr4h4m on 8th Apr, 2017.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

I need to drill the hole for the dip stick but I'm going to leave that for an engineer....


The plan is to run a 6" rod with a dished piston, so I dont need to chop the top of the block....

Now I thought as I was drilling the holes I will need to give the block a good clean, I check the oil plugs and thought hmm these look a bit old..



SO I drilled tapped and pulled them out and they had never been removed. Now this block was purchased from an engine shop, they had all this talk about they know what they are doing etc... Always pay to check even when you are a Fred in a Shed...

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Whats everyones feelings on fully floating V interference fit pistons. I presume that the wire clips will pop out and make sweet love to my bores but I only have experience of small bores

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

With a 6" rod and set of omegas I don't see circlips failing as issue on a specially designed peformance piston. I'm going for the forged omegas with 18mm pin for my build.

Edited by minimole23 on 4th Sep, 2016.

Rather than circlips what about nylon bungs in the end of the grudgen pins as per Wil & Ben's TT?

not nylon! PTFE, nylon wont take the heat.


I like fully floating as it makes things a lot easier during a rebuild, circlips are iffy, bu the spirolocks that you get in omegas etc should stay put whatever you throw at them, but i do like the ptfe lugs for easy of disasembly.

Can't imagine there's anything wrong with circlips, it's the most common way of attaching rods to pistons in a race application. All the 6" rods of the shelf are going to be for a floating pin. I think the only company that do them for a std size big end like yours tho are specialist comp, who sell a short stroke kit of sa 1071 crank, with extended rods.

Lookin forward to see how you get on with this, something a bit different.

I knew that honest

The buttons are no easy with the Pistons that I have as they have cutouts where the pin pushes in.

I did buy a set of 6" rods with standard big ends but... they were reamed for floating Pistons and mine are push fit.
I can return the rods but you are correct the alternative SC versions are floating only. SC have a service to convert the Pistons to floating and secured with wire rings. This looks like the only option if I want to keep the costs reasonible on this build.
I think I will send them off for conversion and I'm very keen to use the longer rod. John K has assured me that even at high rpm they will be ok. I cant see any other options with some large costs.

Edited by gr4h4m on 5th Sep, 2016.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

to be fair it was really the old style clip that could be an issue, modern stuff is an awful lot better

I guess I will find out 😀

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Will you be taking advantage of the short stroke and extending your redline somewhat ?

Phil.

WWW.TURBO-MINI.COM

Well Phil it would be rude not too, that was my concern over the clips, however most of the reading suggests the issues seem to be more with the stamped circlips rather than the wire style.
It doesn't look like there is much option unless I spank a load of cash on some custom rods.
What's your thinking?

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Buy some Omega's and sell the others on.... ?

Could you whip 6mm off the top of the block and use standard pistons and rods?

Just spotted you didn't want to do that.

Edited by minimole23 on 6th Sep, 2016.

I did think about this, but +040 isn't really a common size, and there seems to be a few sets of Pistons still hanging around on eBay, I'm not sure how well they would sell?

I do like the Graham Russell Pistons that are in my current build, they have stood up really well.

It's going to be a medium/reasonable budget build, as much as these things are.

Edited by gr4h4m on 6th Sep, 2016.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

So after some lunchtime texting with Sprocket and having another look at the Pistons, it looks like the best option is to sell my brand new Pistons on and get some floating omegas. What a ballache, the rods were listed as interference but this was a mistake but the seller. They will taken them back but then I can't find rods in the size I want. Either way it's a kick in the nuts!

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

got a pic of your pistons?

whats the issue? your rods are for floating standard pins? (810 thou) so the pistons need to be circlipped or buttoned?

just seen the for sale after posting that^^^

I will say I'd run buttons with those pistons

Edited by Joe C on 6th Sep, 2016.

Joe, the cutout is on the side of the piston massive so the buttons will stick out like a turd in a swimming pool?

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

i have had a quick measure with a simple ruler and the buttons would stick out about 7mm each side, which would be unsupported. I thought you could only use buttons with a full skirt piston, like the Calver 998 flat tops.

Having them circlips machined in will reduce the pin width some, and the omegas seems to have more support looking at the pics on the MED website

Edited by gr4h4m on 6th Sep, 2016.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

nah,

I have run buttons in powermax's and accralites the accs have a pretty deep side notch, Ive got a spare set, bit wont be able to measure the pins till thursday, but nicked the below pic off the web,

I made my buttons so they have very little clearance, if they cant slide out, then the cant fall out.. also i made them pretty much full length so they nearly touch in the middle of the piston, this did mean making them match the taper in the pin tho, bit of a pain, but if youve got a lathe and time....

Ive also got the accralites and bittons, i'll get a pic of them too

looks like my memory is fading, fortunatly i drew them up and posted it thogh!

http://www.turbominis.co.uk/forums/index.p...&tid=9898&fr=25

Ok so some good news the project is back on track...
I asked Keith Calver if he's was Intrested in taking the Pistons back at a discount as I had opened the one of the ring packs and a wrist pin. Now he was great and said he would taken them back.

He asked me why and after a few emails, he recommend having the Pistons machined for wire clips and put me in touch with a machine shop to complete the work.

I raised my concerns over the application of machined Pistons and he put my mind at rest explaining he had built a few autograss engines using the SA crank and circlips machined into the Pistons. Now they turn some serious RPM, so the Pistons are on their merry way to http://damico-engines.co.uk/contact.html seems like it not only Calver who uses them...

On a different not I can't praise Keith's customer service, I would defo use him again.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

I cant argue with that. .......

Aint damico who do SC's work too?