SPX 787 Cyl Head Cover Leak?

[trxxx250r]

I just rebuilt a 787 with all new gaskets and O-rings. I fired it up on the hose for the first time and I am getting a slight seepage of water coming out between the head and the head cover along the inside perimeter. I cannot see the other side so...

I made sure the square rubber rings were in the groove on assembly.

Can you guys think of any reasons this would be happening? It hasn't happened before.

Any tips or tricks? Thanks!

 

[racerxxx]

Never saw on leak there before. I have noticed that aftermarket square cut seals are shorter in height from the OEM ones.

 

[trxxx250r]

Well, these were WSM.

 

[racerxxx]

Not that that is the problem, I would think as long as they were out of the top of the cylinder a decent amount you should have been OK. Was there any corrosion in the groove?

 

[trxxx250r]

Nothing that looked out of the ordinary.

Do you think I should use some silicone grease on them?

 

[racerxxx]

Not to doubt you but you're sure you torqued the head down to the right spec? Those seals are a pretty good interference fit on them. Do you remember if they stuck up past the top of the cylinder?

 

[racerxxx]

I just measured the height of a new OEM set and they were .205" high, just over 5mm in height.

 

[trxxx250r]

Yeah, torqued to spec. They did stick up past the lip. I will measure them when I remove the head tomorrow.

 

[1of500]

Any imperfections on the mating surface

 

[trxxx250r]

Ok, this is extremely embarrassing but I like to be honest in these forums. I forgot to put the big long O-ring in the top of the head where the the cover mounts, lol. Not really funny but an easy fix. That's what I've been talking about. The cylinder o-rings are working perfect. Put it on the hose and it's running great, no leaks and everything is nice and cool.

Really sorry to have wasted your time!

Never drink and assemble a top end! :facepalm:

 

[1of500]

It's ok happens to everyone except [MENTION=57920]racerxxx[/MENTION]

 

[racerxxx]

It's ok happens to everyone except [MENTION=57920]racerxxx[/MENTION]

Lol, damn straight. I will say, I'm always triple checking.

Thanks for following up and posting. You earned my respect. We all make mistakes. Now go break it in and enjoy it!

 

[racerxxx]

It's ok happens to everyone except [MENTION=57920]racerxxx[/MENTION]

Wait........did I forget yours when I built your engine?

 

[trxxx250r]

Took it out today and it is a rocket! No issues!

Thanks for everyones help here!

 

[racerxxx]

Took it out today and it is a rocket! No issues!

Thanks for everyones help here!

Sweet!!!!!