Hey Im changing the head on my 2l conversion as I had oil pressure probs with the current head. I'm obv changing the head gasket and last time round I used the ABF metal one as recommended as it was a 2l conversion and I thought nothing more of it. Since then I have changed a few parts and come to realise the AWG block I have is sometimes quite different to other 2L blocks as its from a Cabrio and overlaps mk4 territory. My longwinded question is should I stick with the ABF head gasket or should I get the AWG one.....my only worry being does it match the mk2 head? For pic reference this is the ABF (048 103 383) and this an AWG one (037 103 383) I would say they are close enough....but need to be sure! Cheers
At the risk of chucking a spanner in the works, why do you think the oil pressure problem is down to the head? It's possible, but more likely to be something lower down.
I would have thought too but dont like to assume after the probs I've had after doing so! Well Mike I've thoroughly checked....in that I've fitted a new oil pump, checked it pumped oil before installing, primed it before start and got a drill fitting on the top of it to fully prime it till oil came out the sensor hole. On start up the head was still clacking but no knocking. Ran flushing oil through it, no joy, ran it with ATF, no joy. Then I read a post saying put the head oil sensor on the oil filter to see if it's head or block....did this and the oil light stopped flashing straight away which made me think....something wrong with the head, which is basically why I'm asking this head gasket question cos I did think it could be a slight difference in them blocking the oil ways perhaps.....clutching at straws though I think!!
I'm not sure that's a valid conclusion/test. If the high pressure oil feed arrangement is the same as what I'm familiar with (EZ), there's a 'pinch-point' for want of a better term where the oil from the pump/filter goes (only) through the gasket thickness sideways (see diagonal channel between two holes at the front, between pots 3/4). If the sensor is in the head you'll be downstream of this pinch-point, if it's in the oil filter housing it'll be upstream, and so in more pressure. I think.
oil pressure readings will be lower at the head than it is in the filter housing, but not significantly so. but if the oil light is on when the sensor is in the head and not in the filter housing, this suggests the cam cap bearings are damaged. this is exactly what happened on my mk2 with a fecked head that being said, since the part numbers differ the reason for the pressure problem could be that the headgasket and head dont match the layout of the AWG block. afaik this block is like the mk4 2.0 crossflow engine, and the heads dont have the same layout in the oil galleries?
Taking the comment about the gaskets into account, did you offer up the gasket to the head to check that the oilways line up? If you take the cam cover off the head, and turn the engine over with the plugs out, you should be able to see oil flowing up into the head, and splashing around the place making a mess (unfortunately). The cam should also be running through an oil bath as it rotates, IIRC, so if you open it up and the head doesn't look like it's got a lot of oil sat in it, I'd have alarm bells ringing. Sounds like you might have to take the head off and compare gaskets, but hopefully you can resolve it before then. There's no substitute for a pressure gauge in these circumstances - it saves a lot of guesswork, worrying about faulty sensors, etc.
This is what Im concerned about. Thing is though it was running for a very short period before one night the oil light decided to ruin things! I never had it on the road though and the one time I did drive it (on a private road....) it wasnt under load. I took the rocker cover off and turned it over with the coil lead off and although there was oil getting up, it was only seeping through and there was definitly no oil splashing around....I reckon I could have put my nose to the cam and come away clean. Ive got a ported head and tsr cam which i planned to install at some point so I've cracked on and decided may as well swap them sooner rather than later....I shall offer up the gaskets to the mk2 head and AWG block see what it looks like and post some pics for those interested. Thanks again guys
Right, here are the pics! AWG block: PB Head: PB head from car with oil pressure probs: I tried the ABF gasket against the head and it matched to what I would say is fine bar one hole between 3 n 4 which is a water way rather than oil way. On the block everything matched up too. On taking the cam off their was a lot of scoring partic under cap number 3 Scoring on Cam: This is a different cam I found (same spec) to compare: And this is the oil way under bearing cap number 3 (avec dog hair!): Is there any way I can see if the oil ways are blocked other than running an air line through them as I dont have a compressor! Would I be ok to stick a bit of wire through see if it comes out the other end?
The scoring on No.3 cam bearing and camshaft is probably enough to account for the low pressure, I'd guess. So you're probably doing the right thing changing the head. The small holes between the pots that you are calling oilways are actually coolant channels. Try shining a torch towards them through the nearest bigger coolant channel (in the head), you'll see they light up. The only high pressure oil feed into the head is the one out of the block next to where you've marked the red X in this pic: To my surprise - and as I mentioned earlier - its only path onward is horizontally through the thickness of the gasket in that little channel between the linked gasket holes into the adjacent (slightly oversize) headbolt hole in the head. Further up this hole in the head there's a diagonal drilling into the main L/R horizontal oil gallery in the head, which feeds all the bearings and followers. Seems strange that there isn't a hole in the head to match the main oil feed hole in the block, until you think about where there's 'meat' in the head for such an oilway, and where there needs to be clearance for whizzy-whizzy cam lobes.
Ok I think I follow that Basically your saying the oil shoots up the hole marked x, is guided to the head bolt hole by the gasket and then feeds the cam in the head through a horizontal channel? So am I right in saying then that the ABF gasket shouldnt be my problem and the oil pressure problem was something internal in the head. So if I fit a different head and a new ABF headgasket I should be (touch wood) ok? Cheers
Yep to all of that (except not really a problem internal to the head as such, more a case of too much clearance for the oil at camcap 3, allowing too much flow and consequent loss of pressure to all the others). The horizontal oil gallery in the head is apparent at each end by the oil pressure switch blocking the N/S end and a core-plug at the cam sprocket end. All the cam bearing and hydraulic follower oil drillings go down into this.
Just a thought while looking at price difference between the head bolts...could a cheapy head bolt have contributed to the problem seen as how the oil travels through one of the bolt holes? BBT charge nearly 3 per bolt but describe them as good quality repro where as AVW charge about 1 per bolt.
The oil doesn't travel through the bolt holes. I've had problems with GSF bolts on a 16v, but the 8v ones have always been fine. AVS sell Febi bolts, which I've used many times with no problem. Also, make sure you clean any puddles of oil out of the bolt holes, as they can cause a hydraulic lock, and sometimes even crack the block.
You were right the first time, the oil holes are the small round ones closest to the cylinders, the coolant holes are the larger triangle shaped ones towards the outside of the cylinder head as above oil does not go thru the head bolts! what you probably saw was that a load of oil had dropped down into some oif the bolt holes when you took the head off. as mike says you must ensure the bolt holes are all completely dry and clear of oil/water before you refit the head, else you risk hydro locking the bolt and cracking the block! looking at the gasket fitment to the block it looks absolutely fine to me, so go ahead and rebuild it with the fresh head. as above the scoring on the old one looks bad enough to account for the pressure drop, i would say its only fit for scrap!
here you go, pic of the blown gasket off my MK1 cabby 16v, note the gasket has gone between combustion chamber and the larger triangle hole in the head. guess what leaked into the piston, hint: it wasn't oil last piccy, look how clean the piston is, steam cleaned itself
