How important is a valve job?

[silvergtjrad]

Ive got some SI stainless valves that I am about to toss into my ported 3500 heads. So far I have only pulled out one valve and it looks like they could be seated much better.

Is there anything to gain/lose from doing or not doing a valve job? I would imagine burning oil and a slight loss of compression.

[ForcedFirebird]

Man, you're just creeping up on the compression, aren't you? The SI valves give a few more 10ths. With 3500 gaskets and valves, you are probably closer to 11.7:1.

What is the condition of the seats? It's going to be much easier to do the valve job now, rather than have to take everything back apart because you didn't

[silvergtjrad]

Man, you're just creeping up on the compression, aren't you? The SI valves give a few more 10ths. With 3500 gaskets and valves, you are probably closer to 11.7:1.

What is the condition of the seats? It's going to be much easier to do the valve job now, rather than have to take everything back apart because you didn't

Yeah, im trying to up the compression a bit. I dont have the motor together, but the pistons are already getting made. 12:1 is what I wanted but the guy at the shop I went to strongly recommended against it. Most likely he didnt want to take any blame for a mistake I might make.

Besides the raise in compression the SI valves up the flow a bit too. If the compression does end up being too high, I'll just throw on my second set of 3500 heads.

The seats dont look bad IMO, but they do look like they could be more flush with the valve. I have to take out the other valves and see how those compare as well. In all probability I'll have a valve job done regardless. Its not like a couple hundred bucks will put a dent in what Ive spent already!

[1988GTU]

If you're that far you minds well go and do it. Couple hundred dollars! For a valve job? That is awfully high. I was charged like 50.00 a head and they assembled everything too(seals, springs retainers etc etc)!

[silvergtjrad]

If you're that far you minds well go and do it. Couple hundred dollars! For a valve job? That is awfully high. I was charged like 50.00 a head and they assembled everything too(seals, springs retainers etc etc)!

Ive got no idea what it actually costs. Im just guessing by standard labor rate. $80/hr x about 3 hours

[Alxsmt]

i say get em done. there not perfect from the factory and im sure the valves need work to fit perfect.

[smilinguy99]

Ive got some SI stainless valves that I am about to toss into my ported 3500 heads. So far I have only pulled out one valve and it looks like they could be seated much better.

Is there anything to gain/lose from doing or not doing a valve job? I would imagine burning oil and a slight loss of compression.

Containing combustion pressure is fundamental to power production. Rings and a valve job are at the center of this. Nice straight guides and seats that are ground concentric with the seats to perfectly seal are always a good idea.

I will also relate this (as best I can remember it) from a book by Bill Jenkins. He said power is made or lost within a half inch of the valve seat.

Don't cheap out on all this effort. Do the valve job.

[MidnightriderZ24]

did u end up picking up the valves from milzy?

[silvergtjrad]

did u end up picking up the valves from milzy?

nope, got them from ben

[ForcedFirebird]

nope, got them from ben

You're welcome :P

[SappySE107]

I modify the SI valves to flow more. Otherwise they flow worse than stock as they come from SI.

Get the valve job done and give them an intake and exhaust valve so they can verify the proper seat.

[MidnightriderZ24]

where the valves a custom set? i want to pick up a set for my 3500 heads...

[gectek]

in response to the title...almost as important as a BJ...hehe