some good info here, helping me along, cheers. using the 8v head as it is in the garage doing nothing and not looking for mega power anyway. the head looks to mate up nicely, havent got hold of any head studs yet to check the rear holes yet though. been busy finishing cage install, bucket seat rails, started prepping underside, fitting 16v hubs, 22mm m/c & G60 brakes - getting there gradually, altho need to do new brake lines now too, might put an adjustable brake bias valve inside the car too seeing as doing new lines now. gonna use an 02A DPA cable change box and mk3 16v flywheel i have knocking about with a passat linkage cos the 020 box is leaking and has seen better days. should work right? i may be able to get hold of a G60 exhaust manifold as we have a few g60 bits floating around in garage too - anyone confirm better to use than mk3 or PB one?
bit of an update - found some rot so been dealing with that. but ready to get head skimmed for raising compression - so to recap 11.5:1 what i should aim for ideally with the piper 285 cam? also for simplicity been thinking about making up a short runner inlet manifold as the mk4 one puts the throttlebody in an awkward place and i'd have to use mk3 TB - if i go ahead with this then what throttlebody options would plug and play with the digi2 system? does a VR6 one have a WOT switch thats compatible?
update - as danster said i had to fill a bit of the oil drain under spark plug 2, getting there though just need a few more gaskets and odds and ends to bolt to it. looks like an engine so must be going ok so far! head skimmed to aim for around 11:1 compression. fitted wilwood bias valve last night running single line to rear brakes. underneath and bodywork tidy up slowly getting there. still need an 02J shifter tower which no one seems to want to sell me separately annoyingly and an 02A starter motor. got a fabia shifter and cables (looks just like mk4 linkage so went for it) got a 'hotgolf' lightened & balanced G60 flywheel (cheers fella) and VR6 clutch kit ready to go and decided to fit a passat pedal box and convert to hydraulic clutch while its apart as the cable clutch parts seem a lot of hassle. heres a pretty picture:
took it out for a quick blast yesterday, feels good! next step mot then get it on the road for testing and then to rolling road for setup. ended up with a custom inlet and OBD1 VR6 throttlebody with homemade digi switch setup. i know digi aint great and am already thinking different management over the winter is on the cards to make the most of the set up and get rid of the afm which is gonna be restricting things.
Good to hear it is up a running now the clutch problem is sorted. There is always going to be a few gremlins in any build though, and sorting them out can be fustrating but it makes it all worth while when it finally comes together. 8v FTW
haha 8v ftw!! we'll see how it goes, still gotta give it all a good shakedown. i'll take some pics when get a chance to give it a clean, cos the whole car is covered in about 2mm of dust and sh*t from sorting the underside out still. probs be next week now what with work getting in the way of my project.
it is supposed to be better flowing. altho the only advantages i can see is modern design(smaller valve stems, better design ports) and not having the inlet directly above the exhaust, therefore the inlet is cooler. I havent seen any reports or information that says they produce more power than the counter flow GTI heads. Id like to see someone put it to the test with matching head specs on a working engine.
Agreed, but only for the above points. Its still not a lot different from the counter flow head in terms of valve position, that is they are all inline with the cam. I honestly think that a true cross-flow head should be just that, that is in one side and out the other, across the valves too so to speak. This pic below is one head off a Ferrari 308, the head is 8v but requires two cams to drive valves. The angle between the valve stems helps a lot too in terms of real flow (If you want me to delete this pic from your thread to keep it clean let me know, its a bit non relevant on a VW forum but shows what I feel is a proper cross-flowing head) Brian.
The counterflow and crossflow heads are very similar in design other than the location of the inlet ports. There are slight differences in the inlet ports of the 2 types of crossflow head available. The "benefit" is that if you are running twin carbs, they are situated on the cooler side of the head which helps to stop fuel vaporization due to the heat from the exhaust manifold. This also helps with clearance issues against servo and bulkhead with carbs or TBs. The pic Brian shows is a true crossflow design as it helps with port angles to the back of the valves. My mates Renault Gordini cylinder head is similar to the one in Brian's pic, and you can actually see through the inlet port, the combustion chamber and out the exhaust port when the cam is in its overlap period and the valves are both off their seats.(with the manifolds off that is). It makes around 170bhp from a 1.5 8v.
done over 300 miles in it now, had it on rollers today and after little bit of setting up got 139.1 lb/ft and 152bhp @ flywheel. really smooth power curve. 30psi in tyres so as not to throw the 'car park' figures up. drives really nice pulls well. looking forward to getting a proper exhaust manifold on it as this is with standard ported cast one and downpipe, and get it on different engine management so can ditch the AFM which must be restricting it and some headwork would be nice in the future to make the most of the ABA head. less than a week til the nurburgring weekend for proper shakedown!!
Well done George. Just goes to show the potential of this setup. It is a neat installation with very few problems that need major effort to sort out. I can see the 16v boys getting a little worried. 8v FTW
the code i put up in my january post was 037103373T. was thinking earlier what would you typically expect to get with just a 2E bottom end and piper 285 (276) cam from an 8v?