Need help: noisy engine after over-rev Options

[emerygt350]

Definitely do the stethoscope to find a cylinder but definitely not a death rattle. Valve train for sure. Are you certain you are getting the clearance correct? What method are you using? Absolutely roll the push rods if it comes to that.

I push my 2056 up past 6k all the time and my bottom end is from the factory as far as I can tell. No money shifts though. No rev limiter will save you from that. I have a 123 but it is not Bluetooth fancy.

[infraredcalvin]

Even if it’s a bent pushrod or broken spring, that means valve hit piston, time to tear it apart and see what damage actually happened.

I money shifted my car on track, locked the wheels and spun, appeared to have no ill effects, ran 3 more events, then 4th (and last for the year) I started losing power towards the end of my afternoon session, then boom, valve broke, sending piston through the top to the case…

[emerygt350]

A cheap boroscope from Amazon might be a good thing to get. Easy to check the pistons without a tear down.

[mepstein]

A cheap boroscope from Amazon might be a good thing to get. Easy to check the pistons without a tear down.

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[DC_neun_vierzehn]

... I was able to pull the push rod out below the exhaust valve to have a look (looked fine, but I didn't know about the rolling on a flat table trick). I wasn't able to pull the push rod out for the intake because it was hitting the HE.

The pushrods should not hit the heat exchangers at all. Ever. Are you talking about the pushrod tubes? Those are not what we're talking about; the pushrods are the rods that actually push the valves open.

You have to remove the rocker arms for a cylinder to get the pushrods for that cylinder out. Remove them and roll them on a clean table top to see if any are bent. Installation can be a bit annoying, but it's easiest to put that cylinder at TDC so the valve springs aren't exerting any force on the rocker arms when you bolt the arms back onto the head. (Because 11 lb-ft isn't enough to seat the rocker arm shaft against the head when working against an open valve's spring!!) Convincing the inner end of the pushrod to stay in the lifter cup can also be annoying; I have been able to push an L-shaped Allen wrench down the pushrod tube and use the short end of the L as a fulcrum to move the inboard end of the rod up into the cup. It fell out, so I had to re-do it a few times, but eventually I got it to stay...

--DD

Interesting. As I mentioned above, after I removed the rocker arm on C4 (the one that was the most out of spec). While I had the rocker arm off, I pulled out the exhaust valve push rod to visually inspect, but I couldn't seem to pull the intake push rod all the way out bc it was hitting the HE (as I recall) as it was almost out. I'll try again. I'll take a pic if the same thing happens.

Also interesting about the pushrod needing to sit in a cap on the inboard end. Not sure I achieved that when I reinstalled it. It felt like it was in place when I put everything back together, but maybe not. That could be contributing to the noise I suppose, but it was noisy before I removed it to inspect. I'll be sure to look for this when I pull them this time.

[DC_neun_vierzehn]

Are you certain you are getting the clearance correct? What method are you using? Absolutely roll the push rods if it comes to that.

I used the method Ian Karr shares in his video. Followed the vid to a T (except my motor is in the car, not on a stand obviously).

https://www.youtube.com/watch?v=XdVIgtpSSJs

[DC_neun_vierzehn]

@DC_neun_vierzehn

A broken valve spring can make a racket, and not necessarily show in a visual. Some can still function, for a while. I have this tool that looks like a stethoscope but it has a skinny rod that goes to a sound chamber and that goes to the ears. You just stick the rod around the engine until the noise is the loudest. And dig in there. Sorry about the engine.

Looks like Harbor Freight down the street has these in stock. I'll grab one today. Thanks.

[DC_neun_vierzehn]

A cheap boroscope from Amazon might be a good thing to get. Easy to check the pistons without a tear down.

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@emerygt350 how does one do this? I've never done this or seen it done. Can you walk me through the steps? If it's easier to call you and have you tell me over the phone, I'll happy to do that and jot down notes.

[emerygt350]

Super easy. The cheap boroscopes have an app that goes down your phone. It's just a little camera on a flexible stalk. The stalk goes down the spark plug hole. If you put the car in 5th you can just gently push it to move the pistons up and down as needed.

Did Ian do the krusty method? That is where you turn the engine (again, fifth gear) until a valve is completely open (pushed in) and the you check the clearance on the opposite side of the engine.

[GregAmy]

I use this for engine inspections, quite handy. WiFi to my iPad or iPhone. Might want to see what replaced it.

https://www.amazon.com/dp/B01MYTHWK4

[DC_neun_vierzehn]

Super easy. The cheap boroscopes have an app that goes down your phone. It's just a little camera on a flexible stalk. The stalk goes down the spark plug hole. If you put the car in 5th you can just gently push it to move the pistons up and down as needed.

Did Ian do the krusty method? That is where you turn the engine (again, fifth gear) until a valve is completely open (pushed in) and the you check the clearance on the opposite side of the engine.

Thanks for the explanation on the how to use a bore scope.

No, Ian did not use the Krusty method. He used the traditional method (find TDC for C1, measure and adjust valves as needed ... repeat at each cylinder in firing order). I tried to read about and understand the Krusty method, but my brain hurt.

[emerygt350]

Super easy. The cheap boroscopes have an app that goes down your phone. It's just a little camera on a flexible stalk. The stalk goes down the spark plug hole. If you put the car in 5th you can just gently push it to move the pistons up and down as needed.

Did Ian do the krusty method? That is where you turn the engine (again, fifth gear) until a valve is completely open (pushed in) and the you check the clearance on the opposite side of the engine.

Thanks for the explanation on the how to use a bore scope.

No, Ian did not use the Krusty method. He used the traditional method (find TDC for C1, measure and adjust valves as needed ... repeat at each cylinder in firing order). I tried to read about and understand the Krusty method, but my brain hurt.

It is super easy and you can't screw it up. The cam only has 4 lobes, so if the intake on cylinder 4 is at its most depressed position, the intake on cylinder 2 is at its loosest, ready for measurement. No caring about TDC or which stroke is happening when.

[iankarr]

My take on the Krusty method is that it's great for people who like to abbreviate the month "June" (IMG:style_emoticons/default/wink.gif)

I know it's simple. I know it involves two less turns of the engine. But I prefer not having to bounce between sides under the car. Yes, I could save 5 minutes if I used Krusty's method...but the downside of me confusing something with the 3 brain cells I have left isn't worth it.