Performance impact of a leaking headgasket

PeteL

Member
I just purchased a new LO206 motor. The previous one was an early version that I purchased used with my chassis and used for 4 races this year. Out of curiousity, I went ahead and pulled the head on the old motor. From what I saw, carbon buildup to the outer edge of the head gasket in one quadrant, it appears I had a leaking head gasket. I am curious as to how much and in what way that woudl affect engine performance, and what difference can I expect with the new motor once I get it out on the track.
 
I just purchased a new LO206 motor. The previous one was an early version that I purchased used with my chassis and used for 4 races this year. Out of curiousity, I went ahead and pulled the head on the old motor. From what I saw, carbon buildup to the outer edge of the head gasket in one quadrant, it appears I had a leaking head gasket. I am curious as to how much and in what way that woudl affect engine performance, and what difference can I expect with the new motor once I get it out on the track.
I had one that we dyno'd and I noticed it would puff when you first pull started it and then it wouldn't do anything anymore. I changed the gasket and head but never got it back on the dyno to see if it was down any from it.
 
If you were keeping lap times you might see a difference but will probably feel the same in the seat of the pants. No real answer, depends how much it was leaking. Don't be surprised if the new motor goes slower until it loosens up.
 
They will leak different amounts depending on when the leak down test is performed (hot or cold.)
As the engine heats up, it generally will leak more if the head gasket surface is burnt.
You will also need to check the exhaust corner of the head as it typically pulls down over time with the localized heat it experiences.
Within the rules, you can very carefully machine the gasket surface to help correct this problem -- IF it's not already too warped. Have a shop that regularly works on 206s and animals do this work though as they know the rules best and minimal cutting can be done.
A new gasket and fresh retorque will usually be enough to keep you going though.


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
Remove the header and loosen and then re-torque the head bolt every so often.
Problem solved.
 
Thanks for all the replies. The old motor is on my workbench, and will probably stay there. The new motor is installed awaiting a proper break in. It has just been started and run on the kart stand for a few minutes. Hoping to get to the track over the holidays.
 
If anyone reading this wants to try it let me know. You supply the engine and the Pixy dust of you choice and i'll do the before and after tests on my dyno. ;)
 
I like to use timesaver during the initial break in. Then, an once of Amsoil break in oil during the break in run.
More to promote engine life not to Loosen it up
 
A non confrontational question.
How are you verifying that the end result is better?
 
No worries....I’m not a snowflake
I haven’t been doing this long enough to be at the end result....Unless you mean the end of break in. I’m not a magic this’ll make you 2/10 faster guy. I do see a consistent up tick from the beginning of breakin til the end. Don’t know it’s a fact but, it always seems that once you get through the heat cycles, the motor picks up 10-20 psi ( I have a little pressure dyno) on the gauge)
.
I write a tag out with each, it has the rpm/ psi/and date. That way, if one of my guys isn’t sure if there’s a motor problem ( most of my customers are new drivers )
I can put it on the dyno and check it and know where it was last time.
 
If a builder told me they were going to use some type of grit or inferior oil product in my new or rebuilt engine, I would quickly find another sane builder. A properly assembled machine done in competent hands should have the machining done in a precise enough fashion that initial running does minimal internal matching. Yes there will be some but it should be minimal. The first oil change with what ever oil I race on may show some debris but I would question my competence if I depend on the initial run to finish the machining for me. Break in procedures have changed in the last 50 years, techniques and capabilities today should build and assemble a machine that is practically ready to go, if not it is shoddy work.
 
I think you guys that are putting grit in your oil to break in a motor are high. but that's off topic.
I see the timesaver on the model t fourms were they use poured babbit .
Good place and its intended use that and bushings with out a reamer .
Bon Ami down the carb to seat the rings fast , no thanks .
 
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