Reply With QuoteNever had any of that happen, knock on wood.
Well in 2012 I was in Kansas and a piece of carbon got stuck between the valve and head and the piston hit the valve, bending the valve and push rod. Fast forward 1 year and 7 days. Coming home from moto gp race on Sunday, got caught in construction traffic on I-69 for about two miles. I was just about to get to the construction and my bike started to mis and the check engine light was flashing.
Apparently it was overheating. It was about 85 degrees out no wind. I got through the construction and picked up the speed and I thought everything was fine.
The next Friday I went to start it and what a clattering sound. Sounded just like it did in Kansas a year ago. So I took it to my mechanic , he told me that I got it so hot that I baked the oil onto the valve springs. And it dropped a valve seat and sounds like it bent a valve and push rod AGAIN.
First has anyone ever had their bike get that hot to where it ran like crap and the check engine light flashes? I an going to have the oil tested to see if I cooked it. Tell me what you all think
Never had any of that happen, knock on wood.
The bike should shut down automatically when it overheats, from what I understand. This is to prevent damage.
Sorry, I'm assuming it's fuel injected? If it's carb'd then obviously this isn't true what I'm saying...
I would find it miraculous if your bike "got so hot it baked the oil onto the valve springs". This would also be hot enough that it should have completely clogged your oil pump, turned rubber gaskets into hard plastic mess, and probably melt a few other things as well. In other words it should not have been running at all at that point. Also I've never come across a healthy engine that creates enough carbon buildup to cause physical damage to other components... so... what aren't you telling us?
You're running synthetic oils too right? Also, how many miles?
2002 s3 thunderbolt. Fuel injected, fully synthetic
"Klotz" oil. It had 40,000 last year. About 41,700 this year. The carbon build up is what my mechanic said what went wrong last year. Always did my best to run 93 octane gas. After he got it apart last week, he check to see if the lifter was pumping oil , said it was. He is at a loss as what happen. He is going to look into getting the fuel injectors flowed to see if they are plugged also, to see if the fan pattern is ok. I am not leaving anything out on purpose , I dont want to put it back together without finding out what happened. So keep asking question and I will do my best to answer them. I need your guys help.
There's a reason I'm not buying the carbon buildup theory for your first bent valve. (Not saying your mechanic lied, just saying it is near impossible).Carbon buildup is usually caused by an extended time running with really bad fuel, or really really really rich (I'm talking its spent its life pouring black smoke), short runs, etc. You'd notice this happening before the carbon would be bad enough to require disassembly. It'd ping, be weak, and generally be strange compared to a good healthy engine.
But lets assume that your engine really did build up a ton of carbon for whatever reason. We're talking thousandths of inch thick layers that can usually be cleaned without taking anything apart. Fuel system cleaner (not octane booster off the shelf but a professional fuel system cleaner) typically works. In other words the way most carbon gets cleaned is by using the engine to literally blow it out the tailpipe. Its brittle, thin, and I've never personally heard of it ever causing a valve crash. Doesn't mean it didn't happen. But *so* unlikely.
So lets get to the most common causes of valve crash. Broken valve keepers. This can just *happen*. Valve keepers have always fascinated me as they are tiny and seem like they would just randomly break anyway. If this is the same valve that was replaced before I would NOT blame the mechanic. I'd call it coincidence. It wasn't the valve seat that failed - it was the keeper most likely. The valve seat is what the valve rests against when closed - to seal the chamber. It may have been damaged AND fallen during the crash process but for a valve seat to just drop out of the head... there's other problems.
Pushrods should bend during a valve crash. In fact this is a good thing and helps reduce shock to the piston and related bearings as well as your cam. Think of it almost as a fuse. Personally I'd hang it on the wall as they always bring up a conversation.
So we are back as to what caused your crash this time. I'd completely rule out an overheat. To cook synthetic to failure your engine would be hot enough that it simply wouldn't work. If that is the only valve and spring that looks cooked AND it was the same valve as last time then its possible the seat wasn't installed correctly and/or your keeper failed (though in the case of the keeper I'd say it was not an installation issue).
im not buying the story, I agree with Lotusexcell, but i dont want to throw the mechanic under the bus automatically, but none of this makes any sense. Ive rebuilt a lot of engines and i wouldnt buy this story with someone elses money. So you got bad info from the mechanic, or just plain bad info.
Pictures of the internals would be a help, but this is one of those situations thats very hard to trouble shoot over the internet.
When i was in aviation school, my powerplant theory instructor used to manage the local Cessna service center. He told us that in any engine shop its common to see them assign the new inexperienced guy to do tear downs of the engines coming in. Which in his view is a huge mistake. Instead a seasoned pro should do the tear downs and take notes on what he saw. think of it as Forensic engine analysis, You cannot correct a problem unless you understand how it happened and how to look for causes and the clues which isnt so easy or obvious.
best of luck on your motor, other than over revving the motor i couldnt begin to guess on this one.
I agree with everything you guys have said. I am not looking to blame anyone. I just want to figure out what happened so it won't happen again.
Didnt get to see valve springs yet, sent the head out before I could look at it. Front valve springs dont have oil burnt on them.
It was the front cylinder last year and back cylinder this year. Here are a couple pictures of the valves we took out last year.
thats quite a bit of oil and carbon, no doubt about it, but im not buying it bent your valve, have you looked into WHY you are getting so much carbon and oil? Valve seals? rings? a wet and dry compression test would be in order for anyone who is having these issues. (If you want i can detail how a wet and dry test works) as well as a full leak down test. part of any diagnostics.
I reread your post and didnt note the mileages before each event. I can show you my Harley Sportsters head and with 60,000 miles on it (Rebuilt into a 1200 around 35,000) and it doesnt have anywhere near that bad.. I dont have the heads off, but periodically i use an inspection micro camera in the spark plug holes and look at the piston tops and valves.
these Buell motors by nature get flogged hard, and sometimes **** happens, but theres always a reason. Id love to be more helpful, and will try if i get more info. at this point,
Here is what i would do absent ANY other info if it was me.
I would pull both heads, replace all the valves with new Kibblewhite precision machine black diamond stainless valves,. NEW guides (Black diamonds Ampco 45) NEW springs from a proven vendor, NEW keepers, and a SKILLED valve job, forget the high fallutin' multi angle jobs, just a basic valve job being careful to get full contact and a good pattern bedded in, but NOT pocketing the seats. If any doubt, then NEW valve seats as well,
then Id pull the cylinders, have a good machinest (not your mechanic) check the bores for wear and your pistons, any doubt, NEW pistons, but at least NEW rings and a good Hone to spec for the rings used if the pistons and bore checked out. new high quality gaskets,
I would consider NEW lifters as well, yours may well be compromised, if in doubt replace them,
ON assy, pull the cam cover and check the cams for proper operation,, look for interference, and grind any possible obstructions, then do a mock up of the top end and do a full rotation checking all clearances, look for coil binding on the springs, shim and adjust as needed,. check rocker arm movements and any interference there, or binding, check pushrods and look for any place they could be binding or rubbing or hanging up, and then do a clay test on the pistons thru the whole cycle (Suck squeeze bang blow) and check for valve to piston clearances. Checking properly with proper dimensions is critical note gasket squish, and torque tolerances.
once it all checks out, then careful assy and break in.
I recomend the Black diamonds as i have used them in over 100 motors and never had a valve failure, their quality is beyond reproach and the choice of every racing team i know, a BD valve will be the last worry you have, I have seen many OEM valves fail, keep in mind valves are multiple pieces welded together, nothing ruins your day like a bent or dropped valve.
These are hydraulic lifter motors, theres actually a lot of clearances built into them to tolerate abuse, there is no reason for the repeated failures you experienced. the parts may seem expensive but the labor to keep doing this over and over again is the real cost.
I hope you can sort this out, but this is something REALLY hard to sort out for you over the internet. best wishes.
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