Sam's build thread

[sambb]

I'm going to call that piston services place today. I'll see what they say RE correcting the ring land flaring in the S3 piston and at the same time modding for more Motorsporty rings. If it's cheap then that'll be the go.
It'd be unreal to go with Honda pistons but first I'd have to get a gauge on rod strength in the ea113 tfsi and early ea888 TSI engines and see how easy/cheap good examples of those are to source and I suppose whether or not their pin end would even be compatible with Honda. TSI are fully floating like 20v but Honda are semi floating aren't they?

[Sydneykid]

We run fully floating gudgeons.

Can't you use the forged aftermarket rods you already have? With Honda pistons?

Cheers
Gary

[metalhead]

I'm with Gary, that sounds stupid expensive. Fly cutting the pistons for the valves can be done relatively simply at home with a drill and an old oversized valve modified into a fly cutter... Might sound dodgy, but I've seen it done with success.

[sambb]

My forged rods are 20mm for the S3 pistons. Hondas are 21mm pin yeah. So for a 21mm pin end rod that'll fit my engine and the Honda pistons I was thinking golf mk5/6 rods.
Could my 20mm forged rods be drilled out to 21mm. That ever get done?

[metalhead]

Also, it looks like you have basically no quench area looking at those pistons - that's probably why the engine has such detonation issues? I'm assuming the chamber in the head looks similar and takes up basically the whole bore area?

[sambb]

I finally got the kick in the arse I needed to properly learn how to string line yesterday. I'd re shimed my left rear a couple of days ago to get 2 degrees neg camber and 2mm toe out. I did all the calcs based on the shims that had already been in there and then going up in the toe/camber settings from there to hopefully arrive at the angles that I wanted. The alignment numbers I had for the removed shims were from a Pedders printout from a year and a half ago.
So I went down to a local aligner that a local Porsche specialist said in the past that they send their customer road cars to and got the following rear toe:

left -1.2 right -0.3 Both toe'd out with more on the left but not enough.

They gave me a freeby because I'd only wanted the numbers which was very very generous. So I figured in the name of science I'd go somewhere else with my 50 bucks that I'd been planning on spending.

left -6.2mm right +1.7mm You'd read that as 6.2mm toe out on the left but apparently not!

Yep was thinking WTF at this stage especially when told by the operator that the lasers read from the back of the laser/paddle on their rig so -6.2mm is actually toe in.....double WTF. They were pretty cheap and being the OCD I am I went to another place where I also got straight on.

left -0.7mm right -1.75mm Both toe'd out but apparently more than double on the right now after a 50m drive.

So it seems that same car same day same tyre pressures etc etc I can have anywhere between 6.2mm toe in to 1.2mm toe out on my left rear. The right side can have a nearly 3mm variance too. The only thing they all agreed on is that I now have an even 2 degrees neg camber on both sides at the back. Precision machines eh? what a cluster f$%#k!

So I went home rigged up car stands, some braid fishing line with sinkers, got out the tape measures etc. I formed the rectangle around the car. Referenced each line to the end of the spindle at the front and at the back used the wheels centre cap ridge to get the car centred inside the string lines. I did 4 separate measure ups. Once because I tripped over the lines after an hour of setting it up and measuring and another after one of the tape measures popped off and dragged a string out of position. The other times because my OCD kicked in again. So after setting up from scratch 4 times I repeatedly have exactly 2mm toe out on the left rear (across a 15 inch rim) and 0.5mm toe out on the right rear. The front had 3mm total toe on the strings and I verified that afterwards with toe plates. I'm pretty dam confident that those are actual measurements. If you assume that I added the corrections to the old/removed shim numbers correctly, then the early Pedders printout from way back was probably still correct because that's the reference I went off.
The first aligner I went to on the day was the only one in the ballpark. I told them it was on 15 inch rims so their numbers are a bit under. If they'd put it in as 14 inch rims that might explain there numbers? But at least they were able to ascertain that the wheels were either pointed in or out unlike one place and didnt get readings suggesting that the other wheel was the one that was toe'd out the most.
So yeah after finding out what I've long suspected I will never be going to an aligner ever again.

[Sydneykid]

For string alignment I don't use string I use hat elastic, 2.0 or 2.5 mm 'ish cheap as from Lincraft,. Since it's elastic I can do things like hook it up over the exterior rear vision mirrors to get it out of the way while I do adjustments. If I bump (that never happens) the elastic it stretches and doesn't pull the axle stands. It also tends not to vibrate so much in the wind when doing rush alignments at the track.

I do string alignments on every race car at least once a year unless there is some reason to suspect the toe plates. Since they only measure the total toe, not individual wheel toe.

Add another 1 mm to the left and you should be good to go.

Cheers
Gary

[Sydneykid]

My forged rods are 20mm for the S3 pistons. Hondas are 21mm pin yeah. So for a 21mm pin end rod that'll fit my engine and the Honda pistons I was thinking golf mk5/6 rods.
Could my 20mm forged rods be drilled out to 21mm. That ever get done?

All the time, 0.5mm no big deal.
I'd still check out machining the S3 pistons.


Cheers
Gary

[metalhead]

Lol, yep! All of that is why even my old f250 gets aligned at home nowadays. The straw that broke me was taking it to have the front toe set as I had been busy with work (so wanted to save some time) and had replaced some tie rods. It came back wandering all over the place and with a steering box adjusted up so tight that it wouldn't return to centre by itself (I hadn't asked for or agreed to a steering box adjustment, they just did it to "help me out"). They told me there was something wrong with the steering box blah blah... I actually pulled over and loosened the adjustment on the steering box before I drove it more than a block, drove it home and parked it until the weekend when I readjusted the steering box correctly and corrected the toe - it had something like 20mm toe out from memory!! Never again. I like Gary's hat elastic suggestion, might have to update my string line setup!

[sambb]

Yep I strung mine up and then looked inside and realised that the handbrake wasnt on and that my pencil torch was in the glove box. If only I could open the door without upsetting the line. Too unwieldy at the track but I was planning on using 2 x aluminium square tubes say 2m wide and putting notches in each end exactly 1800mm apart. Rather than having to measure two separate strings widths from each other I just break out two rods, place them front and back across the stands and then run my pre made/weighted strings (marked length wise too) between them through the notches. I reckon you'd be able to zero in much quicker on squaring the car with the strings doing something like that. Thinking about it front toe is something I'd just do with toe plates anyway. I'd only ever string it to get everything referenced up for checking rear toe. No matter what the angles, adjusting rear toe on the twist beam is DEFINITELY not a job you can do whilst reaching under strings no matter what they are made of!
While I was at it I was able to accurately measure my front and rear tracks. With a front 8mm spacer and SimonK's rear stub axle spacer fitted It is 14mm wider on the front than the rear measured at the stub axle tips, so 7mm per side narrower on the rear. Next thing will be too see if 215/50/15's will fit under the rear guard lip with the extra tuck that the 2 degrees neg rear camber affords. Despite being medium compound I'd really like to run 215's all round at Bathurst this year. With the rear toe out, psychologically I think I'd feel a bit better about having more rear rubber on the back this year. A full 20mm wider per tyre than the 195/55's softs you'd think that'd give me more grip despite the harder compound.

edit: I'm lucky, at work we have a big one of those true flat surface granite slabs so before doing toe checks I can make sure the toe plates are bang on before I use them.