Valve Length Tolerances

[GGress]

I bought some Speedmaster heads last Black Friday, tore them down to check them out and just happened to measure valve length last night. Out of the 8 intake valves the shortest measured 5.036"
and the longest measured 5.042", seems like a big +or- tolerance to me. What should I expect to see for length differences?

 

[RustyRatRod]

How are you measuring? With the valves in the head or out of the head? If you're measuring in the head, you're also picking up the difference in the valve job. So keep that in mind. If you're measuring them out of the heads, then this is just one more reason to check everything with new heads of any kind. We're talking about .006" difference here. That's plenty enough for the lifter plungers to take up, but still, that would make me check them all. If it's only .006" from longest to shortest, I'd call that ok.

 

[GGress]

Measured out of the head, .006" just seems like a lot on something that otherwise is pretty precise.

 

[RustyRatRod]

Measured out of the head, .006" just seems like a lot on something that otherwise is pretty precise.

Although it probably won't make a difference, I think I would want them all the same. Intake and exhaust. And also get all the installed stem heights the same. That will require work on the valve job.

 

[gzig5]

Speedmaster is the Harbor Freight of engine parts. Crap the usually works but isn’t that great out of the box and usually can be improved with some sweat equity. 5.040” +-0.005” wouldn’t surprise me from them. Precision costs money.

 

[Newbomb Turk]

I bought some Speedmaster heads last Black Friday, tore them down to check them out and just happened to measure valve length last night. Out of the 8 intake valves the shortest measured 5.036"
and the longest measured 5.042", seems like a big +or- tolerance to me. What should I expect to see for length differences?

.006 thou? Send it and be glad it’s that good.

 

[RustyRatRod]

.006 thou? Send it and be glad it’s that good.

Kinda what I was thinkin.

 

[MOPAROFFICIAL]

How are you measuring? With the valves in the head or out of the head? If you're measuring in the head, you're also picking up the difference in the valve job. So keep that in mind. If you're measuring them out of the heads, then this is just one more reason to check everything with new heads of any kind. We're talking about .006" difference here. That's plenty enough for the lifter plungers to take up, but still, that would make me check them all. If it's only .006" from longest to shortest, I'd call that ok.

He's not going to be getting 5 in measuring them in the head lol

 

[RustyRatRod]

He's not going to be getting 5 in measuring them in the head lol

With the right tool, he certainly "could". S'why I asked.

 

[MOPAROFFICIAL]

With the right tool, he certainly "could". S'why I asked.

I was picking at the part where he states "5.036-5.042" and you mention "picking up the difference in the valve job" and that would be spring or stem height falling into the 1.907- 1.937 or 2" or 1.65-1.90.
Point is those are two diff things. Your average aftermarket valves are 5 inches 5.011-5.025 and up...so when he says "5..." the valve job is irrelevant.

 

[RustyRatRod]

I was picking at the part where he states "5.036-5.042" and you mention "picking up the difference in the valve job" and that would be spring or stem height falling into the 1.907- 1.937 or 2" or 1.65-1.90.
Those are two diff things. Your average aftermarket valves are 5 inches 5.011-5.025 and up...so when he says "5..." the valve job is irrelevant.

I unnerstand.