Popping sound through RPM

[Juglenaut]

I reworked my exhaust and now it is running but however I feel that the engine has a mechanical issue.

The engine makes a noticable pop through the RPR as you throttle it ..popopopopopp in increasing frequency as you throttle, it is a internal noise as covering the intake filter box makes it more quite, took it for a ride and still can hear a noticable knock and the popping sound apears more like metal on metal but only if you stay on the throttle. I smelled unspent gas coming from the exhaust joints.

I am fearing a thrown bearing or a valve train issue. The popping sounds like misfire but it louder, the car hesitates and has less power.

I replaced the injectors, plugs, wires, ICM, two coils last year, new Fpump, Ffilter, and much more....

Can a bad rocker, or push rod cause this popopopopop or even a lifter?

The last time I heard this racket from and engine the rod fell.

[jp_grasshopper_007]

pull your valve covers and look for an exhaust valve that does not open all the way / or at all. it could have pulled a rocker bolt out and the rocker doesn't even touch the valve, you could have broke the roller off a lifter and/ or wiped out a cam lobe.

[Juglenaut]

Intersting thing is I didn't do the head gaskets and am wishing I redid them when I bought the car back from the dealer. I am thinking it may be a possibility that the rollers were not properly torqued.

If it is a cam lobe the car is scrap simply because I have less time to rebuild and engine and the car is worth squat as a whole.

Using my dB sniffer dodadd I located a radius the noise is emanating, and it appears to be coming from the front bank. Unfortunatly the rattleing noise only appears when driving it.

Based you your input and the past experience with this car this may be reassuring that the valve train has an issue because it it was a thrown bearing it would bang all the time and just get worse.

I do notice some back flow or pulsation coming from the throttle body that didn't notice before, this would be an exhaust valve problem forgot about that, and the map voltage is erratic on throttle, also another thing I just noticed is it appears that some vapor looking smoke comes from the throttle body if the engine turns off just right and can smell unspent fuel once in awhile.

I got spark air and fuel and did all the required checks and also reworked parts of the exhaust.

[jp_grasshopper_007]

wiped out cam lobe would be worse case, but it sounds valve train related to me

[Juglenaut]

I took the front cover off and found nothing wrong, reappling the dB sniffer with the filter box snuffed the noise is centered more or less rear.

Rechecked the manifold gaskets, pulled the engine forward and inspected for a cracked manifold and leaks, none apparent. I ran out of time to pull the rear today.

While the filter box was restricted to dampen noise the hole in the intake tube rubber was a key interest as I could feel blow by pulsations of air on throttling through the hole this is still telling me a exhaust valve is most likely the issue on the rear. Exhaust smells rich.

This weekend when the kiddies are taking a nap I will finish inspection, and if a issue rise up the top engine gets a rebuild if deeper than heads, new intake up if simple, if I still can't find out why the engine is running like shite it is getting pulled for a full inspect and possible rebuild.

I also may be kicking around a 3400 swap ...

[Canyonero]

Sounds like what happened to the blue trooper (burnt intake valve, cracked head).

[Juglenaut]

Fortunatly none of the spark plugs are fouled in any way or form. All the old plugs look normal besides a few that appeared out of gapping, if it were a intake valve I would get near total loss of compression or noticably lower.

My reasoning is on intake stroke it pulls air in with fuel, compress stroke detonation, power stroke, and as it comes back up to exhaust stroke the exhaust does not sound as if it is working right because just as the transition between exh. valve close to intake open the compression of exhaust back flows through the itake port. I am getting a good amount of air pushing back. I believe the exhaust valve is still openning just not much because as the lobe pushes the rod, The valve opens to late and not openning all the way on time can cause a rush of compressed exhaust air in both directions intake and out.

There should be absolute vaccum at all times even at WOT on the intake plenum. Scanning the ecm it appears the fuel ratio is gradually undefinable and under runs, rich flags are triggering at mid range.

I am betting on cylinder 5 as that one with out a proper tool can be difficult to get to.

[Juglenaut]

Top end removed, valve train appears normal. Coagulated oil forming thickly over the inside of rear valve cover. I next hope I have no worse than a blown head gasket. Pressure seems to be going through the crankcase.

Tearing down to block. I purchased a car to get me by while I rebuild the top end and further inspection.

[Juglenaut]

The rear cylinder (Head) is cracked on the number 5 intake seat splitting into the chamber.

I forgot to add that it was the cylinder head, block is fine.

After removing the head it appears that the gasket was indeed replaced, even though when I traded it off it did not need gaskets, got it back with a few more K's and the wit that replaced them appears to have forgot how to sequence the bolts in order and a few were easy and a few were extremly hard to back out. Head is also warpped some and may have cause the bulge of the flex in number five intake valve.

Head and valves in the head are shot, inspection of front latter. Most likely will need a upper engine rebuild.

[Canyonero]

That iron head I posted above was cracked between the valves. Not sure if the burnt valve caused the crack, or the crack caused the burnt valve.

So, think you're going to replace it?