LO206 piston pop up check

At what temperature should pop up be tested? Does the rod grow when it hotter than cool? What about the oil film between the rod and crank bearing?
 
Here is the rule from the Briggs website:
. Deck gasket surface finish is not a tech item. Piston pop up can be .0035” maximum. Piston pop-up to be checked with flat bar in center of piston parallel to piston pin and then again checked 90 degrees to piston pin. Push piston down to take up rod play. . Tech Tool A25.
Angle milling or peak decking is not allowed. d. Carbon build-up can be removed before pop-up is measured as long as material is not removed from the piston. Exception – Competitors can deburr the manufacturing part number/marks IF needed as long as: − Removal does not extend beyond the defined script area. − De-burring does not extend below the original piston surface area. − The original part numbers and script are still clearly visible.
 
At what temperature should pop up be tested? Does the rod grow when it hotter than cool? What about the oil film between the rod and crank bearing?

The rod is not growing at temp, it's in an oil bath and just doesn't get that hot. The head grows because it is operating at significantly more heat.

As for oil film between rod and crank, this is why when I am teching pop-up, I roll the piston up and past TDC than rotate through one cycle and take the "official measurement" the next time it comes to TDC. While it currently doesn't call out this procedure in the official rule set, I think it addresses this possible issue.
 
The rod is not growing at temp, it's in an oil bath and just doesn't get that hot. The head grows because it is operating at significantly more heat.

As for oil film between rod and crank, this is why when I am teching pop-up, I roll the piston up and past TDC than rotate through one cycle and take the "official measurement" the next time it comes to TDC. While it currently doesn't call out this procedure in the official rule set, I think it addresses this possible issue.
I would disagree first very little of the rod is in oil, the length of the rod will grow from ambient temps to operating temps, though the amount of growth will be marginal. If you got an engine which was at the max of the pop up spec, and you got it dismantled and measured when at full temp there would be a measurable difference. That difference would likely quickly change as you check your work and verify the measure. I feel when we get this close the inspector had better start remeasuring and verifying, the benefit of doubt should always go to the competitor.
 
Here's a procedural question that could be an issue if you have an unreasonable tech man...

The rule states you scrape carbon before the pop up is measured. Does that mean you need to declare if you are going to do that ahead of time or can they check it and then you scrape it if it's over .0035?
 
If your pop up is measured with carbon on the crown of the piston and you are beyond spec you certainly have grounds for appeal get your camera out everyone has them. That seems to be a common sense situation, the tools are accurate, the procedure is performed correctly, you either pass or fail.
 
Gary,
Knowing that the majority of these engines are coming from the factory at .000" - +.002", I'd scrap the carbon if I saw excess BEFORE I check pop-up. As a tech man, generally, I roll the piston over TDC once (with carbon) just to see where it's at and how close it is. If it's over spec, then I'll scrape carbon and re-check it. (ie scrape carbon before checking pop-up.) You should never be dinged in tech for pop-up without the opportunity to first scrape the carbon off.


-----
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
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30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
At what temperature should pop up be tested? Does the rod grow when it hotter than cool? What about the oil film between the rod and crank bearing?


The engine is to be tech "as it is raced."
Being reasonable, it will have plenty of time to cool before you get as deep as piston pop-up. Typically, the fuel, clutch, carb, intake, head gasket, and head are teched before pop-up. Now, if you have a tech guy who goes right for the pop-up (and is only "spot" checking for that), I suppose you could find yourself in trouble. Personally, I don't think that the rotating ass'y "grows" that much as it gets warmer.
Oil is squished out as you roll the motor up to TDC in the direction that it runs.
 
When I am teching pop up, I do like Brian said, I roll through it to see if its an issue. Many times no scrapping is neccesary. However, if it is over the limit, I will show the racer where we are at, instruct them what I need them to do (how and where to scrape) and have them let me know when they are ready for a remeasure. I will even provide them with a scraping tool if needed.

My job in tech is to try and prove them legal, not the other way around. Of the 9 motors I have teched this year, I have only had to have 3 scrape to pass tech and only one has had difficulty meeting the spec. However, prior to this years rule change, I was beginning to see many motors with pop up issues due to manipulation. I notice this year there are A LOT of orange seals on the top running karts.
 
I've been pushing to make the POP UP rule more descriptive. The professional tech person probably doesn't need it but the more help the mom and pop tracks have the better.
I would like to see something in there about the type of bar you use to lay across the piston.
I would like it to define the length, width and height of the bar as well as surface finish.
I also would like it to say that if it fails you should turn the bar upside down and re test.
No hot or cold rolled steel etc.
 
Jimbo,
Just use the bar stock that came with the Sox flathead & animal tech kits for checking pop-up - it works just fine for the 206 and is already the official tool to use. No spec is necessary since it is the official tool -- and besides, the rules allow the tech man to use whatever alternative methods they deem fit. You can have one precision mirror ground if you so desire. :)
 
Brian
No offense, but you don't have to tell me or any other professional tech person what to use.
Like i said it's for all the others.
Right or wrong many tracks have put together their own tech tools or have lost pieces and parts of the tech kit.
Then they start to substitute.
Then they get some guy that is a sales man at the local lawn and garden shop to do tech that doesn't have a clue.
Spelling all this stuff out for people helps make sure it's done right.
 
No offense taken.
My point is, that is IS spelled out currently.
I'm not telling you what tools to use, Briggs is.
Sox is the official tech tool supplier.
The Briggs rules also state that
the tech man can use ANY additional tools at his disposal.

I don't know of any lawn and garden salesman who are doing tech. I guess you'll have to enlighten me.
Every one that I've met at the track or at the tech training seminars has been an engine builder and/or racer himself. And some are VERY adept at what they do.
 
I will point out that "Push piston down to take up rod play" is additional verbiage to the 2019 rule set.
 
Al, to say there are no "serious racers" in lo206 racing is ridiculous. By saying what you did you have said there are no serious racers and lo206 racing is not serious. It's a slippery slope. I wouldn't go there if I were you.

To put it simply, LO206 racers don't want to deal with the BS that comes with other forms of karting. The ruleset namely. It's all over the place. But to say that LO206 racers are not serious is very wrong.
 
No serious 206 racers????
Somebody's been injecting disinfectants.
I can tell you that from the Kid Karts to the Masters Class there are a LOT of very serious racers!
From the local level to the National championship level you will find people that do everything they can to be the best they can be.
Just because it's a sealed engine and doesn't make 40 hp doesn't mean these racers aren't competing to their maximum ability.
Just like everything else in life some have more resources than others but just because some don't have those resources that others have doesn't mean they aren't trying their best.
I salute those that show up every week without the best stuff and give it their all and race for the satisfaction of competing!!
I salute those that go home without a stupid $5.00 trophy, a sticker to put on their kart or a cash prize!!
I salute all those parents that made sacrifices to do this with their kids!!
I salute those families that can look back years from now that can say remember when we _ _ _ _ _ _ Wasn't that fun?
I salute the kids that raced and have now grown up and are now racing with their kids!!
 
I've been pushing to make the POP UP rule more descriptive. The professional tech person probably doesn't need it but the more help the mom and pop tracks have the better.
I would like to see something in there about the type of bar you use to lay across the piston.
I would like it to define the length, width and height of the bar as well as surface finish.
I also would like it to say that if it fails you should turn the bar upside down and re test.
No hot or cold rolled steel etc.
Neither bar that I got with my tech kits are perfect...
 
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