Quick Question in middle of a rebuild, Having removed the injectors, i know its good practise to, but is there any reason that i must change the injector seats. Of course im replacing the o-ring seals top and bottom even if the head gasket kit only comes with 4 typically. Are the top o-rings the same as the lowers ?
1.8 pb engine
Pretty sure there aren't any seats, think they're just cut into the inlet manifold.
When I've rebuilt them in the past, I've just done the o rings and I believe top and bottom are the same, thought it's been a few years.
Nope, they have black plastic seats screwed into the head, with out running out and checking, i believe just above where inlet bolts in. I'm of course replacing the o-rings top and bottom. Just unsure if the seats should be replaced
The injector seats themselves rarely need replacing unless you can see actual pitting, cracking or corrosion on the sealing face — most people just give them a good clean up with a scraper/wire brush and a squirt of carb cleaner, then check the surface is smooth and true. If a seat's damaged (usually from an injector having been leaking for ages and cooking the area, or from over-tightening in the past) then yes, sort it, but as routine practice on a head gasket job you wouldn't normally need to touch them — just inspect.
On the O-rings, no, the uppers and lowers aren't the same size on the PB — the lower ones (sealing the injector into the head) are a different diameter/thickness to the top ones (sealing at the injector top/fuel distributor end), so don't assume you can use four identical rings from a generic kit. Worth checking the part numbers against ETKA or a parts diagram before you order, because a lot of the cheaper "universal" head gasket kits only bundle the lower set and expect you to source the uppers separately — sounds like that's exactly the situation you're in.
Good idea replacing all of them regardless of condition while it's apart, they're pennies compared to the labour of going back in if one weeps.