Lifters gave error code

[jonas454]

My dad has owned the car for about 5 years now its a 1999 gmc suburban k2500 with the vortec 454. It made a sounbd once and my dad instantly pluged in the obd reader. The reader stated that something was wrong with a cylinder firing order (I belive it was cylinder 6 or 4). He told me I can have the car if i fix it. So now im comnpleyley disasembeling the car in hopes to have a car. I striped everything down the last few weeks. Im currently in the lifeter vally. I labeld eveything that i coold label. Till now I only found out that a lifter rod was bent and that the lifters 8 or so out of 16 were mesed up. Curently I dont know what to do or how to further proceed. My dad says that the cylinder heads might have a hole in them. The motor is still in the car and my dad and I dont want to reomove it or the engines heads. Anything helps and i will awnser any questions thanks once again. And exucse me for my english since im originally from europe.
Jonas

 

[Sean Buick 76]

I think I would start by removing the camshaft and inspecting it. At very least I would say a new timing set, cam, lifters and pushrods would be needed. I would also remove the heads, however if you leave them on then once I had the cam and lifters replaced and pushrods installed I would rotate the engine over by hand and see if all of the valves are opening and closing ok in the heads.

I would personally prefer to remove the heads as well and have them inspected and rebuilt as needed but I doubt that’s the source of the issue.

I would also inspect the lifter bores for potential damage.

 

[jonas454]

Maybe later on but for now I want to leave the motor in. Since removing it is a huge pain and thanks for the wisdom highly appreciated.

 

[Schurkey]

1999 gmc suburban k2500 with the vortec 454.

It made a sounbd once and my dad instantly pluged in the obd reader. The reader stated that something was wrong with a cylinder firing order

There is no firing-order code. WHAT CODE WAS IT?

(I belive it was cylinder 6 or 4).

Misfire?

He told me I can have the car if i fix it. So now im comnpleyley disasembeling the car in hopes to have a car. I striped everything down the last few weeks. Im currently in the lifeter vally. I labeld eveything that i coold label.

There's a great deal missing here, and you've started disassembly BEFORE it was properly diagnosed.

This will make things much more difficult.

Till now I only found out that a lifter rod was bent

WHICH ONE? That alone could cause a cylinder to misfire.

and that the lifters 8 or so out of 16 were mesed up.

HOW? They're coming apart after the snap-ring broke loose? The roller on the bottom is out-of-round? The plunger is seized in the body?

Curently I dont know what to do or how to further proceed. My dad says that the cylinder heads might have a hole in them.

Cylinder heads have all sorts of "holes" in them. They're intentional.

Why does he suspect a problem with a "hole"?

 

[jonas454]

1. it was a misfire code on cylinder 6.
2. Cant tell if it was a misfire since it didnt fire at all
3. it was on the 6th cylinder
4. The plunger was siezed in the lifters on some the ring brooke and on otyhers the whole upper part of the lifters was bent to the side
5. He means that if the lifters didnt function the valves could have crashed against the pistoon(s) causing damage of any sort

 

[Ace17]

Yeah removing the heads is a bit of a pain(lost coolant, need to buy new head gaskets, new head bolts, etc), but I would do it just for the peace of mind. It'll help you get a better look at possible damage. You could even drain the oil, or open up the oil pan to see if there was any damage below, or maybe just to see how the oil looks - any giant chips or chunks?

You're gonna have to take your time with this one, get a real survey of the damage if you want the peace of mind. As Sean Buick 76 mentioned, I'd inspect the cam to make sure the lobes are still intact. Without removing it, you can put a finger into the lifter holes and feel on each cam lobe for any deep grooves,scratches, etc. When you install the new pushrods/lifters, as you turn the engine, watch to see if they move up and down like they should.

 

[Schurkey]

4. The plunger was siezed in the lifters on some the ring brooke and on otyhers the whole upper part of the lifters was bent to the side

Photos? In-focus, resized, and nicely-cropped.

 

[jonas454]

You must be registered for see images attach

 

[Schurkey]

Thanks for that.

That cannot happen unless the valvetrain has severe issues--broken valve spring, valve sticking in the guide, excessive wear, bent pushrod, etc. The valvetrain for that lifter has to have some amount of clearance before the lifter can come unglued like that. Extreme RPM could do it if the valves "floated" because there wasn't enough spring pressure. But I'm guessing you weren't turning the RPM needed to float the valves if everything else is in good condition.

I see another lifter at the top of the photo with no pushrod. Of all the engines I've worked-on, big-block Chevys seem to be the worst for bending pushrods. The stock 3/8 pushrods are bad enough, but Chevy used really-crappy 5/16 pushrods on some engines. Moving from 5/16 pushrods to 3/8 pushrods also requires new pushrod guideplates to match the pushrod diameter.





I would identify the lifters that are damaged, or the pushrods that are bent. For example, the lifter where the snap-ring popped free, and the pushrod cup is out-of-position. Then examine the valvetrain for that lifter. Is the rocker in position? No excessive wear on the rocker's pushrod cup, rocker ball and pivot area, and valve-tip end? Is the valve spring and retainer OK--LOOK CLOSELY and PAY ATTENTION because sometimes broken valve springs aren't obvious. Is the valve tip mangled? Is the valve tip even with the others--all the intake valves at the same height, all the exhaust valves at the same height? Pushrod bent? Then, pull the spider, the dogbone, and the lifter to inspect the lifter roller and cam lobe. I'd probably just inspect ALL of them, not just the visibly-damaged ones. If you find damage anywhere...look at the mating surface of the part(s) next to it, too.

KEEP THE LIFTERS IN ORDER, and facing the right direction so they can be reinstalled in the same position as they are now. (Even if you replace some or all of the lifters, it's good practice to maintain the relationship between moving parts. You'd keep all the rocker arms in order, and mated to their own rocker balls. Keep the pushrods in order, and know which end is "up"...you get the idea.

IF the cam lobes are not damaged, I can imagine replacing some or all of the lifters, cleaning the lifters you're reusing ONE AT A TIME, and replacing some or (preferably all) of the pushrods--and I'd be using 3/8 pushrods if the engine came with 5/16--so new guideplates, too. What else you replace will depend on what wear or damage you discover during your examination, and a "wild guess" at what should be done based on engine mileage, which you haven't mentioned.

 

[jonas454]

Thanks for all the help. The car has about 120k miles on it and I already took everything out (pushrods, lifters, rocker arms). Not sure how to continue since i belive the cam is fine since there is no visible wear. And im not willing to take out the motor not loosen the heads, since i would have top loosen the whole exahust on it and the bolts have a high probability of snapping. My dad is thinking of a solution right now and im debating of buying new lifters and pushrods and reasemble everything. Then I will see how long it will run or not (pribably not the best idea).
Thanks again for everything