GM positive valve seals - why the 2mm gap at the bottom?

The reason I ask, is because I bottomed the first 2 I installed. Just gently tapped them down using a 13mm deep socket & hammer. Can't find any info on the net, the GM service manual for this engine, or the products website ( Sealed Power [Federal-Mogul] ).

I can't see any reason why bottoming them is bad ... aside from the wear marks on the valve not lining up exactly ... or maybe it distorts the top of the seal where the spring rests? If this thing burns oil after all this work I swear I will detonate the whole unit out back .....

2000 GMC Jimmy engine - 4.3 V6 Vortec "W" .

Donate it to Knob Creek..

Smitty, GM does that just to PISS YOU OFF!...lol

They all piss me off ..... but the reasons why can all be traced back to the EPA.

Now THAT pisses me off!


Knob Creek is some good *censored*. Just so happen to have a large bottle of it here.

Google sucks anymore, i am trying to learn Yahoo search for good results. Here is a thread on the 4.3 but turbo version where they are talking valve seals.
http://www.syty.net/forums/showthread.php?t=10647

Yeah I don't use either one anymore, but if I have a hard time finding something I go Yahoo over Google - I hear too many bad things about Google, so I don't go there.

Thanks for the link Mozz, but that guy has a 1st gen engine there - I've got a 2nd gen. Totally different animal head-wise. Definitely tough finding info on this!

Guess I shouldn't worry about it too much - this engine's been out since '96, so somebody would have a horror story or 2 by now if it was a major issue ... unless I'm the only dummy on the planet that rammed the things to the bottom. That could very well be the case ....

I don't see any harm in bottoming these - do you? Would be impossible to get them straight otherwise ... unless I stuck my dental pick under it & seated it at each "corner" . Sounds like too much of a pain in the ass for me.

I'll get a pic later of the stock seal as they were from the factory with the gap at the base ....

Theres good info here, But it costs a few bucks for each Bulletin. http://www.aera.org/tech-center/search-library/

Thanks anyway .. but I've got enough cash in this thing. WAAAY too much, actually...

Anyway, the engine doesn't blow one puff of smoke - running, at startup, or at startup after sitting weeks. I guess bottoming the seals has no effect on sealing. Didn't think it would, but when I see the factory leave a 2mm gap at the bottom, it makes me wonder ....