Hey guys, quite new to the skoda/vw/audi side of things....

Friend of mine has knackered the bottem end of his engine, I believe it to be carbon build up blocking the oil pickup....essentailly its spun the big end bearings (oil level was correct).

I can build engines to a good standerd having just finishing building my 400hp bmw e30.

So questions, the 1.8t lumps that are used in the octavia vrs/tt/s3 are all the blocks and heads the same, being the only differeances ancillerys and turbos etc???

After being qouted around £1800 for engine and fitment hes a bit gutted....

So my thoughts being, I know of a good/seasoned block that has come from a TT 225.

Will i be able to use this block with his old head and ancillerys? All the other components are fine in the engine (surprisingly) but it will have a full rebuild when its being put back toghether by myself.

So will a TT 225bhp block work with the VRS Octavia engine from a 51 plate.

Any help would be very much appreicated

Thanks

Phill

You'll need the 180's conrods and pistons (and cams?) because the 225 runs a lower compression with shorter rods, but you can use the 225 block and head with 180 manifolds etc. What I'm not sure about is which crank you'd need, and I presume the mains and big ends on the 180 crank are run?

How much lower on the cr does it run (thinking feetling a little with management now). of course spec up the other components...

I suppose what i should have said is the block is a complete bottem end from a 225 1.8. so weather or not the usuall head will fit straight on...

Ah, if you've got a 225 short engine, you could probably put the 180 rods and 225 big end shells on the 225 crank without any issues. Afraid I don't know about CR offhand, but if Lummox picks up on this thread he probably will.

magic, thanks very much for your help buddy! at least its not all bad news with his car!

iirc the rods are the same length but they aren't the same rods, they also have bigger small ends too on the 225 units...

chances are if the big ends have spun then the rods will be ruined and the crank is a scrapper too, although you can get them re-ground they dont last long like that

Well, it was Ross who told me the lower CR on the 225 was achieved by different length rods. Actually, running bigger gudgeon pins makes sense too.

A lower CR would mean less power, unless you remap, when you might get more, but with a weaker off-boost engine.

yea i have litterly just binned the whole bottem end of the old engine, the head is surprisingly all fine. The complete bottem end iv been offered is a nice sweet motor with only 40k on the clock...guy had plans for it in a mk2 golf that never happened and has since sold the head seperatly.

Seeing as im ripping engines apart and building up a new one, whats the basis on tuning for these engines, as said new to them....

with the bmw engines its ARP bottem end an top and your good to go with 1.2 bar of boost all day long (with a good tune of course!)

again thank you for the help

wouldn't want to go 'gainst what ross has said, but.... the 1.8 engines have always used rods with 144mm centres and that even includes 8v units too(except 1 little rare beastie with 1H engine code), the longer 156mm rods are used on the 2.0 engines...

the 1.8t rods will have either 19mm or 20mm small ends for the gudgeon pin depending on spec/engine code, you can use an 8v rod (20mm small end) in a 20v lump but not the other way round (the 20v rod has no hole through the centre to feed the small end)

I was a touch surprised by that too; I'm more used to manufacturers dropping CR with bigger chambers, lower piston crowns, and sometimes dished crowns. After all, a long rod reduces peak sidethrust for a given stroke, and that's a good thing. This is heading slightly off-topic into engine design theory though.

haha its all good....

i was a bit surprised by that aswell.....people tend to suffer with the M20 bmw engines when the put the 2.0 rods in to try an lower the cr....they never get near peak figures when using 2.5 roads and theres not much in them....

thanks for all the help guys

I could be wrong, sorry to misslead but thats what I believed.

Either way there is no harm in my view of rebuilding the AUQ with BAM parts anyhow, lower compression is no issue especially if your planning to remap anyhow.

Different part numbers for the con rods for the AUQ and BAM, thats why I assumed its how it was done.

haha its all good....

i was a bit surprised by that aswell.....people tend to suffer with the M20 bmw engines when the put the 2.0 rods in to try an lower the cr....they never get near peak figures when using 2.5 roads and theres not much in them....

thanks for all the help guys

that's to do with the speed of the piston, a longer rod accelerates the piston up and down the bores quicker, the piston dwells at tdc for a shorter period, there is always a time delay between tdc and peak pressure, and as the longer rod is already on it's way back down before peak pressure is reached...

anyway... off topic:O

in this case the lower compression ratio is achieved by a bigger combustion chamber volume because the shape of the piston crown is different.. i'd have to look it up but i believe also the 225 units have forged semi slipper pistons too instead of hyperetic skirt jobbies