S2 engine rebuild

[BW2309]

Not sure if interested but aswell as killing the odd S2 I also keep em going!!

Just started an engine rebuild for Shark_90 on here...thought I'd post a few pics so far....

[quattrokid]

this should be good Ben, PLEASE do it like 4V6 and give us loads of phots and an idiots guide as to what things are, what they do and what your doing to it.

Being a 20v lump I am REALLY interested in following this one

I am sitting comfortably..... you may proceed

[BW2309]

I shall take as many pics as u like!

I'll be stripping the block a bit later before getting the head polished up and manifolds matched. I flippin love engines.
I'll keep u posted on proceedings!!

[quattrokid]

luvvly jubbly thanks Ben

whats wrong with the engine, could you give a bit of history on it please and why does it need a rebuild?

[BW2309]

Originally Posted by quattrokid

luvvly jubbly thanks Ben

whats wrong with the engine, could you give a bit of history on it please and why does it need a rebuild?

The car's done 199k miles ans several track days. Although it was running well it needs a turbo and was generally a bit tired. I know Shark_90 very well and we'll be using this S2 as a track car so if Steve's gonna drive it I thought I'd best make sure the engine's strong!!!
Just wan to get it safe, reliable and constant in it's power delivery, like Steve's old one I did years ago.

New stem selas, gaskets, piston rings, bearing shells etc should freshen her up and matching the manifolds and polishing the head will help responsiveness, free revving and keep lag too a minimum.

[shark_90]

Ah ha, my engine! In pieces!!

A bit of history is as follows:

I've owned the car for just over 2 years and have used it for track days and a couple of jaunts across Europe. It runs very well and has always been pretty quick but it was smoking a little on gear change and it was time for a bit of a refresh. It has done 199,600 miles with the last 20-25k being rather "hard work" and so I decided to treat it!

Looking forward to driving it again already, I've barely used it this year at all. It'll be at Audi Driver international on the AV Performance/Shark Performance stand, but most of the day it'll be on track.

It's going to be fun running it in again

[BW2309]

Couple more pics -
You can see that even after 199,600 miles the bores still have cross hatching on them - they're perfect with no lip.
The Biggest issue here was corrosion blocking the coolant path ways around the head gasket.

[BW2309]

Pistons out....

The big end and main bearing shells on this engine all in very good condition given the mileage!! Obviousdly new ones going in but atleast they weren't down to the base metal like the last couple I've done!

As you can see, the side of the piston that is NOT inline with the gudgeon pin is the bit that takes the most force. As the cylinder fires it attempts to twist the piston in the bore. This is clearly shown by the slitghlty shiny bit near the base of the piston slkirt - still not bad at 199k though. You can still see the machining lines in the pistons - they'll go back in.

Looking in line with the gudgeon pin, the dark discouloration shows where the rings have alowed some combustion gases past into the crank case. This is fairly normal but a set of new rings will make all the difference, bring the compression ratio back up to spec!

[BW2309]

Don't know if anyone saw in Audi Driver about the 5 pot engines building up carbon in the sump that subsequently blocks oil ways and the pump, but this is how it looks! This on'es not bad and is only high up the sides of the sump but it's this build up that flakes off and clogs the oilways up!

This is caused by a mixture of, incorrect oil used, worn rings and lack of regular oil changes.