Whats the difference between odb1 head and an odb2 head?

[Hoppa 0]

Need a bit of help please people %-6

Went to collect my car from a garage last night after the head was replaced, and found the mechanic still working but the car not. ( No compression in 3 cyclinders

~ What actually happened was that he could not source a head and i could so had it delivered to him, he said looked fine so got on with the job, now he is saying the head must of been no good. What he also mentioned was the fact it was slightly different than the old one (after he had put it on!!!) ( it has a whole on the passenger side which you can see chain through and some of the parts attached were slightly different (he used some of the old bits). Now I need to get my facts right so that I can get some money back from this cowboy!

Any help or advice will be appreciated 8)

[FishWick 21]

He's not talking about the chain tensioner bolt hole is he? I would hope not! Does this hole face the bulkhead or the battery? I've heard some OBD2 heads do have some kind of emission control additions but the valves and cams etc are identical to OBD1. Can he not plug the hole with something?

Is yours a dizzy one or does it have a coilpack?

[kilokilla 0]

the hole he is talking about is an oil way to oil top chain obd 1 has a little 1p size hole whereas obd 2 has a big triangle hole this is only difference ive noticed between both heads and wont affect the running i would suggest timing is out on one of cams or bent some valves when fitting.

[kilokilla 0]

could also be knackered lifters not opening valves hence no compression.

[Hoppa 0]

Thanks for the help, much appreciated.