Landracing Forum
Bonneville Salt Flats Discussion => SCTA Rule Questions => Topic started by: Grandpa Jones on August 23, 2013, 07:14:17 PM
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Hi all,
Wondering about the difference, why bikes teardown for their first record, and cars can seal the
engine and be measured later?
Anyone know the history behind this?
Cheers, Dave
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Bikes can seal and teardown later too. Some bike engines difficult to check. Some people just like to get it done before the end of the meet.... and the tech people probably appreciate that. Don't know any history on that.
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We were told that is no longer done. Measure on the first return run record, and then seal for the rest of your event. Your seal expires in 365 days.
Some engines dont need full teardown, depending on plug position and available access to that plug hole. If you have centered plugs, consider that "straight in access" during your build. If the inspectors cant get the full length of their tools straight, you will have to tear down. Be prepared for them to have accessible seal bolts, pre drilled.
Think as you build, "how can I make this easier for the inspectors?". For example, next time, I will have photos of the top of the piston, so they can see what they are trying to feel.
Also, make sure you know where your valves are during the stroke or bore measurement. You will be the guy turning the crankshaft. Dont be doing that with a ratchet handle that might let the cam lobes suddenly spin the crankshaft. Be prepared to turn and hold that crankshaft accurately and securely.
Regards, JimL
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And if it's a 2-stroke you're pulling the head regardless of plug position.
I know that for a fact. :-D
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Quite a bit of seasoned knowledge by a six-year-old.
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As the Impound Steward I have set the procedure for the car side. I let the m/c guys operate their own program. I do know that as the week progresses we get some cars trickle in for measurement during the slow periods. This helps keep the staff awake and earning their meager salary. Down side is that I have been in 3" of water certifying engines. There can be an overload of work on the last day but, not to often.
I think Matt and his staff try to avoid that issue.
On the car side the paperwork is in the hands of the competitor and their responsibility. If lost = no record.
DW
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A few years ago is the most recent time I had the pleasure of being in impound, and at that time Tom Evans was still the head honcho. His attitude towards measuring the bike's displacement revolved around doing it after the return run had established that the bike got the record - because, as he said, if you blow it up later in the event -- you can't measure a blown up engine. He also suggested doing it promptly to get it done and out of the way. I haven't been in impound (except to visit, dang it) since Matt took over as chief M/C guy, so I don't know what he and his minions are doing in re: the measurement now v. later thing.
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Hi Slim when you did visit impound with your ZX12R was it a head off job or did the Measuring tools fit ? P 8-)
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Neither. The tool would not have worked -- the spark plug hole is off-center. But (especially) since the claimed displacement was about 6% less than the class high limit -- they oil pumped it. The number they came up with matched the measured displacement (from when the motor was built). Someplace around here I've even got a photo or two of the thing being tested. Shall I try to find it?
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Slim, If I claim my motor is undersize for my class can I opt for the oil test vs a teardown? I'd even pay for the oil.
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A few years ago is the most recent time I had the pleasure of being in impound, and at that time Tom Evans was still the head honcho. His attitude towards measuring the bike's displacement revolved around doing it after the return run had established that the bike got the record - because, as he said, if you blow it up later in the event -- you can't measure a blown up engine. He also suggested doing it promptly to get it done and out of the way. I haven't been in impound (except to visit, dang it) since Matt took over as chief M/C guy, so I don't know what he and his minions are doing in re: the measurement now v. later thing.
From my what I have seen Matt runs it like Tom use to. After my record run I pulled the pushrods and they air pumped my motor. When Tom pumped my motor it was way under the size limit so no problem (889cc in 1000cc class). This year I was way over the limit so no problem either (3340cc in unlimited or 3000+ class). Both times were painless.
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Unh, Vin, it doesn't work like that. That is -- if they were to pump your engine and it showed pretty close to the limit -- they'd likely ask you to next let them mesure it more precisely - via a spark plug hole or even with the head off. Don't mess with 'em -- remember, arguing with an inspector is like fighting a pig in the mud. The pig likes it. (I've seen that posted in the SCTA bike inspection trailer - so you know they live it).
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The 12 port head I ran had a near vertical spark plug that was not near the center at all; in fact was within 1/2" of the side. The stroke was easy to get and I built a tool to measure the bore. It was made of a fairly hard wire with a loop in it at edge under the sparkplug hole. I attached a fine fish line to the short side. It was exactly the size of the bore. With the piston at the bottom I put in the tool and you could see through the sp hole it sat flat on the piston and could not "wiggle" This proved the bore.......It was fortunate the piston was flat.......The tool had rounded ends was was measured prior to putting in and after taking it out. The fish line made removing easier with the piston at the bottom.....good luck
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Neither. The tool would not have worked -- the spark plug hole is off-center. But (especially) since the claimed displacement was about 6% less than the class high limit -- they oil pumped it. The number they came up with matched the measured displacement (from when the motor was built). Someplace around here I've even got a photo or two of the thing being tested. Shall I try to find it?
That would be good if you could slim just trying to cover all our bases we need to learn as much as we can before next year :-) Cheers phil
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ok, I got to ask!
can I get my engine measured before I make the first run?
Just thinking out loud here, but if I were to do this, get engine sealed I wouldn't have to worry about it, just concentrate on the other million things on my mind.
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I have done that. If you contact the association board and give your location, they may be able to steer you to someone near you who can inspect your engine and seal it. At the salt i don't know.
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Last year and the year before I ran the sidecar in gas and fuel. I got the gas record and went to impound. I pulled the head off for the measurement. As I have a single its not a problem. After the measurement I had the engine sealed. Went out and got the fuel record. Seal in place. No measurement. No problem. At WF my gas record was taken.
This year I went to get it back and was just barely successful (by .511 mph). When I got to impound last years seal was still in place. Seals are valid for 365 days. When I went to impound I didn't realize it but it was the 364th day of the seals validity. When Matt checked my log book he was happy and no teardown was necessary.
I believe you can get the engine measured and sealed before an event. Best to check with Matt or Tom to be certain.
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I've never figured out how the seal magically becomes invalid in 365 days. Did it just dissolve? What was the reasoning (or lack of) behind that rule change which was made in semi-recent years?
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I've never figured out how the seal magically becomes invalid in 365 days. Did it just dissolve? What was the reasoning (or lack of) behind that rule change which was made in semi-recent years?
Stan, I usually put on a few pounds every year, so I am guessing SCTA uses that same logic to figure our 500 could have grown to a 550. :cheers:
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I can think of one potential reason that the folks in inspection/impound won't measure and seal your engine before you make runs. Assuming you ask for a measurement early in the race event -- the inspectors are very busy inspecting and would probably rather get all of the bikes done and racing before taking the time away from that to measure. Ask them a few days after the beginning of an event and they'll be more likely to measure you then.
Remember -- I'm just making an assumption here. Ask the inspectors, email Matt, and keep in mind what I've said.
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What does the rule book say, and the Bonneville operating procedure.
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I can think of one potential reason that the folks in inspection/impound won't measure and seal your engine before you make runs. Assuming you ask for a measurement early in the race event -- the inspectors are very busy inspecting and would probably rather get all of the bikes done and racing before taking the time away from that to measure. Ask them a few days after the beginning of an event and they'll be more likely to measure you then.
Remember -- I'm just making an assumption here. Ask the inspectors, email Matt, and keep in mind what I've said.
I would think What SSS has said makes sense. What if everyone wanted their engine checked and sealed. Takes time and how many of those would set a record and how many wouldn't? I guess if only a few wanted it done and the guys weren't swamped it might work or like has been mentioned done at some point prior to a meet,
Sum
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Folks in SoCal can often take advantage to having a nearby inspector seal an engine before an event. Saves a lot of time during the event -- and a seal is a seal.
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Sometimes sea lions are mistaken for seals!
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Very old seal are sometimes referred to as "seal"ocancths.