cylinder head holes

[vw.monkey]

Hi Guys, I have a 69 Bay Dormobile with a 1914 Engine and 44 webbers
and have recently had to cut short a Devon and Cornwall after 14 days of wild camping, Paradise! trip due to excessive backfiring leading to cylinder 1 and 2 failure.
i've tried all the obvious, new spark plugs, distributor cap, rotor arm, coil, fuel pump, ht leads, fuel filter, compression test, had the webbers stripped and checked. I did however I did find part of the carb base gasket missing.. so I used my cornflakes box to tap out a new one! and all this by the roadside in Sidmouth.
Sadly I had to give in and had no choice but to give in and call the R-C, who after an hour of fiddling cam to the conclusion cyl 1+2 are not firing. after 12 hours and 3 low loaders I made it home.
after removing the heads I could find nothing no bent valves, no holes in pistons, no cracks?
But I have found some od Slots in the cyl head as Pictured, I think they are from the machining of the head, if they are not meant to be there why is the compressing ok?
I'm in the process of putting it all back together and going from there.
VW Monkey.

 

[sparkywig]

Whoever machined the heads has broken through into the casting.

 

[atafonso]

Some stock heads don't have enough material on the sides of the chamber and when you cut for 94's it shows a few holes. As long as the sealing surface is fine, you could run these heads. But i would not recommend it as it can be very thin at the bottom of the chambers too and it can crack in no time.
Most new aftermarket heads even in stock form such as the Empi ones comes with a solid chamber, which have much more meat and can be safely cut to 94's without fear or crack in those areas.
Bottom line: run the ones you have if you have no choice, but if you can, get better heads.

Abel

 

[vw.monkey]

Thanks for your reply, yes it's a Harry Harpic 1914, only done 3000 miles in 4 years
44 Webbers 111 cam at £5,500 not sure what to think.
This occurred due to not putting some kind of locking nuts on the inlet manifold to head, Carb worked loose, sucked in cardboard gasket (found in combustion chamber) End of Holiday..