Just been having a look at why the exhaust was sounding a bit poppy; turns out its not the exhaust but there is a leak where No 2 barrel meets the head - I can feel with my hand exhaust gasses escaping. So I'm going to wait for it to cool off and check the head nuts are tight - but can I do all the nuts with the tin-wear in place? Anyone got any other ideas?
No you can't...you need the cylinder tin off, so engine out. Are you sure it's the barrel, not the exhaust joint on the head? Pop the rocker cover off and try & retighten the nuts you have access to (to the correct torque). If you find some that won't tighten down, may be that the head stud has pulled out of the block (not unknown).
Are you sure it's the barrel and head?? What have you done to come to this conclusion?? Try a compression test. With an air-cooled engine you can easily get leaking exhaust gas confused with cooling air. They are not the easiest to diagnose. Redex is great for showing leaks. Try some down the carb and then (with a glove or other item) cover the exhaust and see if the smoke is escaping from around there. If its a T4 engine you can do it in situ but you'll need to remove the tinware. T1 engine will have to come out as Snooty says.
Thanks, that's useful. It a type 4 2.0L. I can feel a blade of hot air coming out at the joint, and can hear it using a bit of tube as a stethoscope. I've had a feel round and listen round the manifold and that seems fine. Should be cool enough now to check the head nuts - I'll let you know how I get on.
Try the bottom ones with it in the van. Don't go mad - use a torque wrench, but wait until it's stome cold.
On dear, I can only get my socket on two of the nuts because the rocker shaft is in the way for the other two, but both were as least as tight as the 23ftlbs setting (though I've got to admit it wasn't stone cold, there still a little residual warmth from my run earlier, but really not much). I'm not in the mood for taking the rocker shaft out tonight as its now raining and George Gently is on soon. I'm planning a trip out next week to Dorset in it and won't get time time to fiddle again so I'll see if Like at Terry's Beetles and help me out Question though- can I damage it running with a leaky head?
Are you sure it's not a leaky hx/head join? Have you tried the exhaust nuts? They're prone to stripping in the heads.
Yes, pretty sure. The jet of hot air is definitely coming out of the barrel-head joint. When I put my listening tube there it made my ear ache with the pulses and noise, there's no sound from hx-head joint. To be honest I'm frightened to death of putting a socket or spanner on the hx nuts- they're just begging for me to round them off! But Luke did give them twist when it was in its for it mot a few weeks ago, so I really think they are ok.
Type 4s are prone for leaking between the barrel and head... They had a shim/gasket fitted that leaks like I don't know what... I don't fit them, just lap the barrels into the heads, and check the deck height to make sure that it's not less than 1.22mm
I believe VW deleted the copper gasket thing on T4s eventually, as they were more trouble than they were worth.
After reading this, http://www.ratwell.com/mirror/www.dolphinsci.com/techbull.html I didn’t fit head gaskets when I rebuilt my 2.0l TypeIV engine.
The last T4 heads I bought came with a big red label stating that fitting the gaskets would void the warrenty. They have a "shelf" machined into the heads to compensate, but if you remove the gasket when you reuse your existing heads you'll increase the compression ratio unless you add shims under the barrels to compensate.
should the exhaust gasses be getting past the rings... I am sure I had a leak once and it was the oil dripping..
Thanks guys or the messages. I'm currently phut-phutting round Dorset but am looking forward to getting her up on the ramps and engine out. Suggestions for the best source of new heads would be welcomed. Are the ones from VWH any good?
I'm going to continue this thread if I may until I've solved my phut phutting, mostly because I need help from you guys but also because it useful log of lessons learned and a reminder that my original diagnosis (which I was so convinced about) appears to be wrong. So, to add some context, meet Joyce (and yes she does look like the backed of a Bus): I did a compression test yesterday and these were results; 1 10.4 bar 2 10.1 bar 3. 9.7 bar 4. 10.2 bar So it looks like my suspect no 2 cylinder is actually pretty tight after all, in fact both banks seem to be performing pretty well! Just to prove it; But; she is still popping from No 2 - when I pull the plug lead off the popping stops and she actually runs more smoothly on the other three cylinders (she still pops when the other leads are pulled one by one). So tomorrow it's time to get underneath with some redex and take a look at those manifold bolts again. I'll let you know how it goes. D
Finally got to the bottom of it! Not the head at all after all, of course, but a rightly snarled up head gasket - take a look at this: ...and this is it once out. I didn't bend it at all getting it out, this is how I found it! God knows how it got in that state, but there does seem to be a manufacturing defect on the seat where there was a burr (you can just see it on the bottom left corner. I've shaved it off now with a Dremmel. As far as I know these as the original heads, so must have always been there. So a mercy dash down the M3 to JK yesterday got me sorted with new gaskets and manifold nuts, which I fitted today and now she's finally running smoothly and quietly, at least for now. All sorted for about £10, no need to take engine out, no need to fork £100s on new heads and barrels, and now I know she's got pretty good compression, so that's all good then!!!
