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I think that's where the R99 around here comes from?
In any case, one reason I gravitated to the 7.3 is the ability to run B99.
Originally Posted by Dan V
-.0007 from nominal? What is the spec?
Per the IH book 0.31185-0.31255". The zero corresponds to 0.3122".
Originally Posted by Peixinho
I just wanted to point out those tests were done on a MAX EFFORT tune. Unless you are towing/daily driving on a heavy race tune then you won't see those numbers on that combo.
I think my big question is are forged rods, that have been beat on for a few hundred-thousand miles, stout enough to take a build that's pushing 1000tq with it coming on fast in the RPM band for another few hundred thousand miles?
So .0003 under the low limit. Do you find the same values on all the valves? Are the uniform end to end?
Using gage blocks or a gage pin to set the Indicating micrometer?
I calibrated the mic against a set of hoke blocks a few months ago, but could prob stand to be done again. Measured at three points along the stem. Most of the valves show a tenth or less of deviation, while the fails exceed the tolerance a little at one or more points. Pictured one was by far the worst.
I can't imagine what a broken-in engine would have on the intake valve stems and guides after running without an air filter for a few thousand miles or even regularly maintained miles!
I realize that you are putting together a very high dollar engine here and want everything to be absolutely perfect, but three ten thousandths is splitting hairs (literally). What happens to the valve stem when it gets warm in the first few minutes of operation? What happens to the guide and the seat? They all grow and they all grow at different rates....and measuring things at room temperature really doesn't tell the whole story.
I guess you could buy a few hundred intake and exhaust valves and pick the 8 of each that are closest to specification. I'm not trying to be demeaning or sarcastic....but realistic in what is feasible in this world!
I only have the IH book to go off of; whether it's being overly conservative or not I can't say because I don't have the real world experience. Ultimately up to what my machinist thinks but thank you for helping to put things into perspective. Honestly I didn't know anything about engines a couple years ago so all of this is a learning experience.
Originally Posted by cleatus12r
can't imagine what a broken-in engine would have on the intake valve stems and guides after running without an air filter for a few thousand miles or even regularly maintained miles
For fun. I think this one has maybe 200k on it. It becomes a tenth under sized below the groove. Not bad for iron guides?
Man do I get a kick out of the..... .00005. Really? 1/2 a tenth? Or in machinist speak...50 millionths.
So the person working in the local IH dealer measures to .00005? ....no, they don't.
IH is looking for not less than .0016 clearance, but up to the max of .0055...if you can sort through and find uniformity around a number, add .0016 to that...and that should be your reamer size, to the minimum....if it cuts on size. You might pick .002 larger...or find a standard reamer in a size that is within your desired spec.
So the person working in the local IH dealer measures to .00005? ....no, they don't.
Don't know how widespread they were at the time this was written, but they might be using digitals that read out that far (but aren't accurate to that). Probably added +- 50 mil to the tolerance so that someone with poor mic touch doesn't chuck a valve simply because it reads one "graduation" higher/lower on their Mits digital mic?
Don't know how widespread they were at the time this was written, but they might be using digitals that read out that far (but aren't accurate to that). Probably added +- 50 mil to the tolerance so that someone with poor mic touch doesn't chuck a valve simply because it reads one "graduation" higher/lower on their Mits digital mic?
If you're going to work in 50 millionths...you better be in a temperature controlled facility.
I have a Mitutoyo 1-2" digital micrometer that reads .00005....too many numbers. It's precise, but not for my shop. I set a mic like yours today...and mine only reads to .0001
I have no personal experience with the 3-stage mechanical but based on what I have been told by DPS, the 3-stage mechanical is to the HD electronic what the original mechanical is to the original electronic i.e. completely different animals.With the mechanicals, there is aboslutely no feedback on actuator position nor is drive:boost ratio tunable. Depending on how you look at it, that may be a good or bad thing.
The electronic is better on paper no doubt but price is quite high. If I were to get one it'd be mechanical. I wish they'd source some beefier turbine wheels to sell with their housings... honestly the biggest thing that holds me back.
Seems like BW stuff has shot up in price since I bought my system; the 0.83 gated housing (13761009026) is between 450-650 online.
Your 363 and .91 that you already have is a great match for the 205/30. I think you should go with that and keep your focus on getting the engine built.
