Injector seat and washer installation - advice please

[Trevor]

Got myself into a tizzy trying to install these and have probably overthunk myself into a corner.

I have these





I've removed the injector and old seat, this is what I see looking down the hole



There are no washers present at all in all 4 injector holes, I've checked the old seats and injectors in case they were stuck. I fairness the head went off to be pressure tested and maybe they were taken off and chucked as part of that.

The Haynes manual suggests this is the right order



My dilemma is two fold really:-

1) The washer in the photo has a rounded profile facing uppermost and a flat profile underneath. Which way up does this need to go?

2) Putting this washer into the base of the injector hole in the cylinder head just looks odd to me, is it really going to seal against the crescent shape at the bottom, or does this washer go into the bottom of the injector seat and the injector seat itself goes into the bottom of the hole?

Option 2 seems the logical choice as the washer fits inside the seat nicely and I imagine will form the seal when the injector is torqued down. I will of course get a cotton bud and clean the hole first.

 

[Chris]

What's it look like on TOYO?

C

 

[Trevor]

Toyo and the FSM seem to suggest that the washer goes between the seat and nozzle, so I read that as washer inside the seat. Neither show which way up the washer should be i.e. should the flat surface of the washer contact the base of the seat or the bottom of the nozzle.

 

[Chris]

This is difficult by distance Trev. I'd be fitting all the bits together to see how they feel really. And I'd be cleaning that hole out too.

Have you dropped a washer down t'hole to see how it fits? Will a washer fit inside the seat?

 

[Trevor]

Washer fits inside the seat like a goodun so that seems right, if I drop washer down t'hole it falls through so that's a no no.

So now all that remains is flat down or flat up in the seat, the washer must have the different profiles for a reason. All I can think is that the flat side might be at the bottom, allowing the rounded profile to crush against the nozzle bottom to create the seal. But t'other way up could be true too.

 

[Chris]

I'd have thought that as it is in your pic would be the natural orientation. How does it sit up against the injector - both ways? The cup is flat so it would make no difference there, so it must be the rim of the injector that makes the final call. Looks like a crush seal on the rounded side to me

 

[Trevor]

That sounds plausible to me Chris, basically both the seat and nozzle surfaces are flat so no real clues there. I assume that the seal is to stop gases blowing from the engine upwards past the nozzle. Maybe the flat surface at the bottom ensures the seal created by crushing force is uniform?

 

[mrdelmonti]

Always been rounded profile to injector when I've replaced crush washers on past cars.

 

[wobbly]

Is that crescent shape below the washer/seal normal ?

 

[Trevor]

All 4 are the same so I think normal.

 

[Trevor]

Thanks for all your help, all in torqued up now. I'll add the pics into my rebuild thread when I'm further into the project.

 

[ModelMakerMan]

Sorry a little late to the party, been away this weekend.

Injector seat goes into the hole in the head then the washer goes in domed face up (should fit into the very bottom face of the seat) then screw the injector in. The crush washer seals against the nozzle cap.

Did mine last year.

 

[Trevor]

Cheers Dave, it a relief to know I've done it the right way.