We need new heads for Betty The current head on the right keeps coming loose and leaking, and valves on cylinder #2 appear to be drilling their way into the head - need constant adjustment to increase clearance and the intake has now reached the end of the available lash adjustment. Main requirement is reliability and longevity. Any improved breathing would only be secondary benefit, but I'd rather pay a bit more for good quality casting and machining. Planning to buy from VW Heritage because I live nearby and can go and look at the things in real life. Looking at these standard ones: Autolinea 35.5/32 £435.92 pair https://www.vwheritage.com/04310135...-x-32mm-85587mm-single-valve-springs-vw-spare EMPI 35.5/32 stainless, SCORE £409.90 pair https://www.vwheritage.com/043101355e-cylinder-head-1600cc-twin-port-complete-vw-spare and this possible bigger-inlet-valve one: IAP/Kuhltek 39/32 stainless £563.90 pair https://www.vwheritage.com/ac101322...mm-85587mm-with-single-valve-springs-vw-spare http://iapperformance.com/product/e...c101322c-041-style-85-kuhltek-motorwerks.html Got all excited about buying a pair of Mofoco 040, at £584 for a pair, but there's a long lead time on those. My budget tops out at around £600 for a pair. Any strong opinions?
The Autolineas are fine in my experience, although they might have gone downhill since. Worth finding out why your head is coming loose. Head studs pulling out? Also why the valves are receding. Lap the new valves before using the head.
What snotty said.. loose heads could be the studs pulling out the case. Receding valve seats likely caused by overheating, so look into that before cooking another expensive pair of heads.
Thanks for the replies and tips. I heard second-hand that the previous owner has considered the current heads "a bit cheap" and that they didn't fit very well. So I'm hoping the whole problem is down to poor quality manufacture. Will check studs in block, and diagnose the receding valve issue. Seems to only affect cylinder #2, the other three are fine. Has never idled properly, I suspect #2 has been lacking in compression for some time. And if the inlet is leaking then it'll be affecting #1 too. Thanks Mick, I've grabbed your heads
The EMPI heads with the stock size stainless valves as fitted to the JK Preservation Parts 1641 seem to cool better than the original German variety, or the Autolinea stock heads, although some of that may be the engine builder trying harder to clean off the flash. Receding valve seats is mixture and heat related. Heads coming loose is not the fault of the head. Heat again... Sort out everything not just the heads.
TES sell reconditioned 1600TP heads for £100/ea. I have a pair on mine and get 125psi on all 4 cylinders, have ran them for a couple of years now with no issue at all. Gives you some money left over for new/bigger twin carbs ;-) But as others have stated, the looseness is more than likely due to the stud pulling out of the crankcase, and the valve recession I'd guess is because of the overheating which also pulled your head studs.
^this. Sick studs'n'valves would imply your engine's been running hot, so best fixed before fitting shiny new heads...
Go over the inlet manifold looking for holes . Marvel at the brake booster hose outlet left unplugged. Seen that at Techenders.
Further updates: the old heads are not as nice as the Autolinea ones I bought from Mick. The old ones had thinner fins, less metal around the top end of the cylinder, and over-chunky castings around the valve guides, especially in the intake ports. Also the chamfered holes for the push-rod tubes seemed to have been chamfered quite a bit too deeply. But, yeah, overheating. #2 inlet valve wasn't sealing very well (!) as the seat was completely loose and hammering the port. Push-rod tube seals badly affected by overheat, and leaking. Exhaust stained intake port on #2. Not a happy head. The dodgy head, cylinder #2 on left (eek, where's the intake valve going!), #1 on right (not too bad): #2 inlet valve seat completely loose, valve sitting about 5mm into the head, rocker arm directly pressing on the spring retainer: not a lot of sealing possible, lots of noise, not much power! Next question: it seems that the stock compression ratio was 7.3. Initial measurements suggest the new heads and existing cylinders will result in a ratio more like 7.7: is this too high, or is it OK with modern petrol?
I found the Autolinea heads I bought ages ago were in some ways better than the original VW ones. 7.7 CR is fine. Just use normal unleaded: 7.7 is still ridiculously low by today's standards.
