97 Rocker Valve Adjustment
 

I understand the rocker valves can't be adjusted, but some research I read said its a must if I removed anything removing the rocker arms, such as the heads, which I did to replace blown head gasket.

Any who, when I came to the point to reinstall the rocker arms and rods, I just placed them in and tightened them down, torqued at 40 lbs. Truck starts up then has loud knocking, then dies. Did more research and says I'm supposed to turn the engine to TDC #1 and finger tighten them, then tighten them until there's no play in the rod, then torque them to 20 lbs :icon_werd:. So now I'm guessing I over tightened them, which is why it doesn't stay started after it fires up. So this time when I adjusted them today, I just watched the rods extend all the way just before they drop, then finger tightened them, then tightened them to what I thought was 20 lbs of torque ( No Torque Wrench ). Letting battery charge before I try to fire it up again ...:icon_lurk5:. ​​​Could that be right ? What happens when you over tighten the rocker valves and try to start engine ?

Also, just by watching the lifters, am I adjusting them right ? If not, can someone expierenced in this area please simplify how to correctly adjust the lifter/rocker arms, specifically on a 1997 Blazer VIN "W" 4.3 Vortec !? Thanks in advance !!

I think your engine probably has the bearings knocked out of it by running with no oil pressure as you previously described. Thought you was going to replace this engine (the one with the head gasket replaced that had a problem with the oil pump drive shaft).

I just lifted it and took the pan off, the bearings were fine. My oil pressure sensor was broke and didnt realize it, causing no oil pressure on the dash gauge. Do you know how to do the proper valve adjustment on this year model ?

With the net lash arrangement of these engines, you torque down the rocker arm nut and its done. There is no adjusting them. Simply torque the nuts to 20 ft lbs. 20ft lbs or 40 ft lbs, the nut comes up against a stop and doesn't turn anymore. As long as you don't twist or break the stud, it won't have made any difference in the adjustment. You will need to look elsewhere for your problem.

I've had it scanned twice and no trouble codes came up both times. My uncle is a mechanic of 20+ years, he scanned it with a $300 Boshe Scanner, when he seen no codes he assumed the lifters were too tight. He said if their too tight the engine won't start and if it does it'll stall. So I'm going to charge this battery and try to start it. After that, I don't know where else to go...no trouble codes, no security light, no engine light, and crank but no start ? I'm stumped...

• Do you have correct compression on all cylinders (need compression tester)
• Do you have correct fuel pressure (need fuel pressure gauge)
• Do you have electrical pulses to your injectors (need noid light)
• Do you have spark at 1) the coil, 2) at the spark plugs, and ) if 1,2 is OK then is the distributor oriented in a manner that will distribute the sparks correctly. (All of this can be checked with an extra spark plug and a pair of vice grips to hold it to engine ground)

Scanner will not tell you any of these things, but may be needed later for something else.

If you want to go through these things, collect the tools and we can begin. Many can be borrowed with deposit from a local parts store. Otherwise I'm not going to be able to help you.

Ok I appreciate the list of tools I need, I have a light tester and a multimeter, can any of those be substituted for the noid light ?

It's possible, but quite difficult to make the connections with a test light. Better to get or borrow a noid light (they're quite inexpensive) and be sure to get the correct spacing to fit your wiring harness where it plugs into the MPFI Spider.

The first three things to check are so easy and quick.....

Test the fuel pressure at the Schrader valve with key on engine off. Should go up to around 58-60 psi for 2 seconds when the key is first turned on and then drop back maybe 5psi when the fuel pumps shuts itself off. System should hold this pressure for a while. If you find a problem - we will have to fix it.

If Fuel pressure is OK - then remove the connector that goes into the top of the MPFI spider. Inspect the pins in the Spider for any bent ones, and the connector for any damaged or backed out wire terminals. If OK, install the noid light across the circuit of your choice and have someone crank the engine while you watch. If light flashes you're good on a lot of things. If not, we will have to fix it.

If first two tests are OK, disconnect the coil wire at the distributor and install a spark plug into the end. Ground the spark plug to something metal by clamping lightly in place with the vice grips. Have someone crank the engine while you watch. You should observe spark out of the coil. If not, we will have to fix it.

Go through this stuff and report. These are the quick easy things that can send us in the right direction. If all of this is OK, we can go on to more difficult things to do. If you find a problem with the easy checks, then we can focus on that.

Ok I'll buy a noid light kit, where exactly would I plug in the noid light ? Do I need to remove the upper intake to get to it or is the wiring connected on top of the spider ? Or the name of the piece so I can google it. I really appreciate the info man, real big help !!

Its just the connector that plugs into the top of the spider. Unclip it on both sides, disconnect it, and turn it over to plug the noid light in. Just pick any pair of the 12 terminals (2 for each cylinder). You'll see when you do it. If not just ask. Don't forget to inspect the pins in the tp of the spider that push into the connector for being straight - and the wiring terminals for in the connector for not being pushed back.

PS I'll be flying out of state starting early tomorrow morning to attend my son's wedding. Be back Sunday eve. So don't get discouraged it I don't answer in the meantime, but I might get on my cell tomorrow night if things break up early. Can't promise.

OK congrats on the wedding :icon_toast: so I bought compression tester gauge and fuel pressure from Harbor Freight ( see first pic ), these look about right ?

OK so now I'm trying to buy the light noid set and AutoZone wants $25 for there's ( see second pic ). Does this noid set look about right ? Can't really afford the $40 set at Harbor Freight...

OK I've gotten the light noid, fuel injection test gauge, and engine compression test gauge.

1. Tested the fuel pressure, turned on the key and the gauge immediately jumped to 60 psi, then dropped to 0 after 2 seconds.

2. Tested the injectors with the light noid, tested every injector, and they all lit up as the engine was cranked.

Lacking a spark plug socket at the moment so I can't do the compression test just yet.

So far so good ?

Need to figure out where the fuel pressure is going after fuel pump shuts off. Should maintain 50psi+ pressure for some minutes. If it is going to zero immediately after fuel pump shuts off, then this is probably the cause of your no-start. Please advise fuel pressure during cranking for 5 seconds and we will know for certain if it is a problem or not.

Having the noid light blinking tells us the Crank sensor is "sensing", and the PCM is electronically trying to drive the fuel injectors injectors. Also means that Security is not preventing it from starting (security shuts off fuel injectors through the PCM).

OK compression test is complete, I'm uploading the results I wrote down (see pic).
Cylinder #1 - 150 psi
Cylinder #2 - 0 psi
Cylinder #3 - 120 psi
Cylinder #4 - 125 psi
Cylinder #5 - 0 psi
Cylinder #6 - 130 psi
I'm guessing cylinder's #2 and #5 are clearly dead, but I dont know what I'm looking for in these results. So with these results, what seems to be my problem ?

​​​​​​​P.s. - my fuel pressure gauge sprays fuel from the hose connected to the gauge. So before I try the fuel pressure test again, im going to fix that, dont want fuel in my eye again lol

My harbor freight fuel gauge leaked. I just wrapped teflon tape around the threads.

ok cool I bought mine at Harbor Freight too, I guess I need the teflon tape too !

There may be more causing a no start, but definitely need to figure out cylinders 2 & 5 before going on. Let's pop the valve covers and turn the rocker nuts out a couple of turns on both valves for both #2 and #5 cyl, and repeat compression test. If you get compression with the nuts backed off, then you know something happened when overtightening the rocker nuts to 40 ft lbs and we can deal with that. If you still don't get compression we can deal with that too. Also look at the valve action on those cylinders when cranking and note any differences. As an aside, what about the test for spark out of the coil?

OK, there's spark from the coil...

I read an article about a "wet compression test" I should perform after the first test readings from those 2 cylinder's. Look :

From article - "The results you obtain from this second ‘Wet’ compression test will help you determine if the low compression you recorded in the ‘Dry’ compression test are caused by worn piston rings or worn cylinder head valves."

CASE 1: The compression value shot up.. This tells you that the piston compression rings are worn out and thus the problem is in the bottom end (block) of the engine in your GM 4.3L, 5.0L, or 5.7L equipped vehicle.

Here's why: The engine oil helped the piston rings seal better, thus bringing up the compression value almost back to normal. If the problem were in the cylinder head valves... the engine oil you just added wouldn't make a difference at all (on the compression value).

CASE 2: The compression value stayed the same.. This confirms that the problem is in the cylinder head valves.

Here's why: If the cylinder head valves and their seats are worn out (or maybe even bent from a broken timing belt), no amount of engine oil is gonna help seal the compression in, in the cylinder. So, if the compression value, for the specific cylinder you're testing did not go up (after you added oil to it)... then this is a dead giveaway that you've got cylinder head valve damage.

OK now my question is, where can I add oil to these cylinders besides the spark plug holes ? Oil leaks back out when I add it there.

It's a typically valid test that you have found, but I think it does not apply very well to your particular situation. The test assumes low compression is found (not zero compression). If you have zero compression in a cylinder, then either you have a hole in the piston or a serious valve problem. I'm betting on a valve problem after tightening those nuts to 40 ft lbs. So please do the tests I described in post #17 (backing off the rocker nuts a couple of turns on those two cylinders) and report. Also don't forget to observe valve action while cranking. If we find any rocker stud/nut damage, these are screw-in rocker studs that can be easily changed!!

If loosening the nuts doesn't restore compression, then you need to remove the rockers completely and attempt to pressurize the cylinder with compressed air (yes at that point you would need to borrow an air compressor and a hose to adapt to the spark plug hole). Be careful when plugging the air into the cylinder - the crankshaft will turn as much as almost 180° as the piston goes to the bottom of its travel and you don't want any fingers cut off in the belt pulleys. Simply listen to where air comes out - if it blows out the intake it is intake valve, if air blows out exhaust it is exhaust valve, if air blows out the crankcase it is a piston. This a crude leak-down test.

As an aside, true leak down testing uses a leak-down testing device that measures pressure drop across a small restriction in a 100psi regulated air supply flowing into the cylinder through a 0.040" orifice. The more the cylinder leaks past valves or rings, the more the pressure drops across the orifice. Less than 10% pressure drop across a 0.040 orifice due to cylinder leakage is considered excellent. Race engines can get less than 5% and sometimes even lower (better seal = more power). Over 25% leak-down is considered bad. Again, you can tell where the leak is by listening and comparing cylinders.

As for valve adjustment on a 1997 Blazer - once you are sure valve train is OK, you want to simply torque the stop-nuts down against their stops at 20 ft lbs. Nothing more, nothing less. Easy-peasy!

ok I'm about to loosen the rockers on those 2 cylinders now. Also sealed my fuel pressure gauge, ran another test and it took the pressure quite awhile to drop to 0. Hopefully its the overtightened rockers, because getting an air compressor is going to be really tough to come across. I really appreciate the help !!

Great! It's never a problem to help a young person who wants to learn how to fix his own vehicle and does not give up easily! You are the exception, so kudos to you! Please let us know the results of the compression test with the rocker nuts loosened.

I'm just curious..... from your old posts in various threads it seems you bought your Blazer earlier this year and replaced intake gaskets because of coolant in the oil. Then trouble with batteries while cranking to try to work on engine. Then trouble with distributor and engine knocking and you posted a pic of distributor with milky oil all over. Then some talk of replacing engine for a while. Then more recently the talk of overtightened valves, a no-start, and discovery of 2 dead cylinders. Was your vehicle bought as an unknown non-running project? Looks like a nice one in the photo you posted in your Garage. Have you ever had it running on all 6 cylinders or has it always just barely run (at best)? Can you tie all of this together for me? Just trying to understand the big picture here.

If you end up needing an air compressor and can't borrow one - I suppose there are tool rental companies that have them for rent.

p.s. this is the reason to keep your posts in same thread so readers can understand problems from the beginning, the diagnosis, and the repair sequences that were undertaken.

Yea I'm really anxious to drive it, its my first SUV. First day I bought it (March 6), it started up and I reversed it and pulled it up the tow truck, seller told me it was a blown head gasket and it was leaking coolant around the drivers side bottom intake and valve cover. They also said it ran fine then died all of a sudden. They never started it up again and sit for 2 weeks before I bought it. When I made it home, I drove it to my apartment checked the oil etc. Drove it outside the complex to do an oil change ( put 6 QTS of oil in 😱 ) along with Bars Leak Blown Head Gasket Fix to try to seal the head gasket...hasnt started since. Took it to a buddy's and pulled the intake. Found the valve cover gasket wasn't on right and the drivers side intake was really loose ( I twisted the bolts loose with my fingers ), allowing coolant to leak and with the gap between the valve cover and the head on drivers side, coolant was draining into the head, sealed it up, with new intake gaskets, and screwed my distributor up by not aligning the shaft with the oil pump shaft and I started it up. It had a really loud bang when it ran this time. So I shut it off, went to set TDC using a screwdriver in plug hole and pinched the screwdriver tip and broke it in the head, seizing my motor. Took to grandpas to pull head to get the screwdriver tip, then decided to change that gasket while I had the head off. Put it all back together, tightened the valves to 40 lbs, and hasnt started since...and this where i started posting for help. But Im going to try to do whatever I can to get it running before I quit on it !

OK, I loosened the rocker nuts and did the compression test on those cylinders. Did it on cylinder # 2 and read 120 psi. Did the same on #5 and it read 115 psi. Went to torque them down, starting with #5, and tested five again, and it stayed at zero again. Pics are the readings...Also discovered my passenger side upper intake gasket is blown/broke, also in pic. Could that be a problem too ?

P.s. I didnt mean to post a new thread, I thought I was replying lol

Now we are getting somewhere!!! I would source 4 rocker studs and stop nuts for those on cylinders #2 and #5 (these are quite specific for vin W 4.3 engines in late 1990's /early 2000's - so don't try to substitute anything generic), install them, torque them, and recheck compression to make sure you still have it. You may later want to replace all 16, but I think right now we just want to get it running for minimal cost. The orange gasket is damaged from installing the plastic part of the intake. You will definitely need a new gasket, so might as well buy the upper intake set. Coat with Vaseline and take care when installing the plastic past of the intake. There may be other things to fix before it runs, but that is all for now. Install and report. Any questions about installation please ask.

Was there any observable marks in the piston from the screwdriver tip? If so please describe.

You had mentioned a new distributor at one time - did you get oil pressure after install, or hasn't it run since install?

What do you mean by "valve train is OK" ?Does that mean to make sure the valves are open when I torque them down ? And is this the intake/valve diagram for my engine ? Says its for GM 4.3 Vortec, but doesn't say the year (See pic)...if not can you draw it out for me ? Also, how do you tell if a valve is open ? Is it when the rods are all the way up or all the way down ?...when I tightened these, I didnt do anything but torque them. I didnt know if I was to look for the valves to open or not, and I'm still curious...I'm sorry, took me almost a month to fully understand the timing process lol

"Was there any observable marks in the piston from the screwdriver tip? If so please describe.

You had mentioned a new distributor at one time - did you get oil pressure after install, or hasn't it run since install?"

Oil sensor broke, replaced it and has oil pressure now. The pic is cylinder #1 where the tip was jammed. In the other pic, are #3 and #5 open or closed in the position there in ? And do I need to tighten the rocker nuts in open or closed position ?

Right now you have verified that the valve train for cylinders #2 and #5 needs repair. So fix that so you can torque down the stop nuts and still have compression. This is what I mean by the valve train being OK. Don't need to worry about having the engine or valve in any particular position when you do it. Just torque to 20 ft lbs.

But FYI, a valve is open when the push rod is all the way up.

Ouch, looks like the piston got pretty beat up with the screwdriver tip. Definitely not good, but shouldn't keep from starting. Guess it should be a try it and see if it lasts type thing. Maybe the piston gods will shine on you and you will get away with it!

Can't see any valve train for #3 or #5 in 2nd photo to say anything about. Only thing there would be the lifters and I can't see them.

Again, rocker nuts can be torqued with valve in any position. It doesn't matter.

ok I have it packed down with the rocker arm torque and position, tighten them the but til it stops then torque it to 20 lbs, thank u for clearing that up. Yea my grandpa told me the piston wasn't that bad and I got lucky. So my next job is to pull the studs and replace them, luckily I grabbed extra when I broke one and had to replace it. I tightened it til it broke.

OK, I didn't recieve your last messages before I did this. But I followed this tightening procedure :

"4.3L Vortec Valve Adjustment

To prepare the engine for valve adjustment, rotate the crankshaft until the mark on the damper pulley aligns with the 0° mark on the timing plate and the No. 1 cylinder is on the compression stroke. You will know when the No. 1 piston is on it's compression stroke because both the intake and exhaust valves will remain closed as the crankshaft damper mark approaches the timing scale.

With the engine on the compression stroke, adjust the exhaust valves of cylinders No. 1, 5 and 6 and the intake valves of cylinders No. 1, 2 and 3 by performing the following procedures:

Back out the adjusting nut until lash can be felt at the pushrod.

While rotating the pushrod, turn the adjusting nut inward until all of the lash is removed.

When the play has disappeared, turn the adjusting nut inward 1 additional turn for 1988-93 engines or 13/4 additional turns for 1994 engines.

Rotate the crankshaft 1 complete revolution and align the mark on the damper pulley with the 0° mark on the timing plate; the engine is now positioned on the No. 4 firing position. This time the No. 4 cylinder valves remain closed as the timing mark approaches the scale. Adjust the exhaust valves of cylinders No. 2, 3 and 4 and the intake valves of cylinders No. 4, 5 and 6, by performing the following procedures:

Back out the adjusting nut until lash can be felt at the pushrod.

While rotating the pushrod, turn the adjusting nut inward until all of the lash is removed.

When the play has disappeared, turn the adjusting nut inward 1 additional turn for 1988-93 engines or 13/4 additional turns for 1994 engines."
Now after I did this, I have no compression in any cylinders, even with the nuts backed off. Though, I think my compression gauge isn't working, the pressure release button is stuck pushed in. So I'm either going to unstick it or exchange it for another. On hold until then, but I'll remove/replace those 4 studs until then.

[QUOTE=Lesmyer;677136]So please do the tests I described in post #17 (backing off the rocker nuts a couple of turns on those two cylinders) and report./QUOTE]
Ok I fixed my compression gauge, the air release button was stuck. Backed off the nuts on them and ran another compression test. Had compression 120+ in all but 1 cylinder, it had 60 psi. But my battery was dying by the time I was getting to that cylinder. So I'm charging my battery and jump starter tonight to insure it doesn't die during testing in the morning. Due to those cylinders not getting compression while torqued down, I still need to replace the studs, correct ?

PS ... As long as I have at least 100+ PSI in every cylinder and there is none less than 75% of the highest cylinder, she should fire up and run, right ?

If you have no compression on #2 and #5 with rockers torqued to 20 psi, but compression returns when you loosen the rocker nuts - then the stop surface on the studs and nuts are damaged and they need replaced. The nuts are turning down past where they should stop when torqueing and this is holding a valve open. Make sure you replace the rocker nuts too

You shouldn't notice any miss on a cylinder if compression is above around 60 psi. I once had an old V8 that was so worn out that it had 60-80 psi on all cylinders. It ran fine with no misses and didn't even use much oil, but was very difficult to start in cold weather and had little power. Came from beating it up and down those white rock gravel roads they have in Iowa with no air cleaner or muffler for a year or so. Thought I had a hot rod!! This car ultimately ended up being my first successful engine rebuild. I won't even comment on my first try when I was 14 - that was already a lost cause when I started.

Good luck. Don't forget there can be other things preventing from starting, but without compression on all cylinders there is no reason to even try to start it. If it doesn't start after these repairs, let us know and we can go through checking the distributor and it's installation. The rest you pretty much have already covered.

Keep in mind that it will be very hard to start after squirting oil in the cylinders (requiring extrended cranking), and then it will smoke like crazy and run poorly for a little when it does start. Probably you will want to crank it over for maybe 30 seconds with all the spark plugs out to get as much oil out as possible before putting them back in.

Thats awesome, your first engine rebuild was at 14 ? Yea this Blazer has 245,000 miles on it. I realize I'll need to replace it soon, but I need to at least last until I can work some time to get the money up.
OK I had to return my compression tester to get money for a tool set (Stanley 226-Piece + 70-Piece Bonus Mechanic Set) to remove the rocker studs. What should I look for when I take them out ? And I cant afford "new" studs and nuts, but I live less than a mile from a salvage yard, can I pull studs and nuts from a salvage yard from engine with low mileage ? And if so what should I be looking for to avoid buying ? And can I pull the studs from any 96-2002 4.3 with the screw type studs or I need to find a specific vehicle ?

You should be able to get the studs and nuts from any 1996 up 4.3 Blazer or Jimmy or S10 pickup. Should be plenty of them in the junkyard. Mileage really shouldn't matter. They don't wear.

Yeah, first attempt was at age 14, but it never ran again. This should be good for a laugh. Tore it down because of a couple of spun rod bearings after driving my car around the farm for a couple years without changing the oil. Finally so much dirt that oil filter couldn't pass sufficient oil. Yes, my Grandfather sold me a car against my mother's wishes when I was 12 (for $21) and I virtually lived in that car with big dreams of doing stuff with it, etc. Consulted with my great uncle who told me I would need to smooth up that crank with emery cloth. So I went at the rough crank with emery cloth for quite some time, and bought new bearings and rings from JC Whitney. Bolted everything together and it was locked up tight. Discovered that if I loosened the rod bolts a little on the cylinders that had spun bearings, it would turn. So I bought some shim stock and made shims to fit between the rod and cap to spacer them out. Didn't bother to hone the cylinders. Re-used the head gasket. Put the engine back in and filled it up with straight water, which went directly into the cylinders and hydro-locked it. Ended up burning up the starter trying to get it to turn again. It sat for a year with water in the cylinders and then I pulled the head and discovered all the rust.....
.

I can't believe I said 20 psi and not 20 ft lbs.

Thats awesome ! U started at 14 and your grandpa sold you a truck for $21, thats a sure deal for real ! What's emery cloth ? Thats quite an experience to learn for your first time. What happened to the truck in the end ?

its OK I understood lol my new tool set arrives today, so I'll be pulling those studs today and I'll take pics when I report.

Emery cloth is like sandpaper, but the backing material is cloth instead of paper (so it is a lot more flexible and strong) and the cutting material is made of "Emery" - premium stuff. Comes in rolls about an inch wide. Pretty expensive, so usually you tear off a length that you need and buy that. You don't see it a lot any more.

Actually he sold the car to me (he really gave it to me - it was worth a lot more) when I was 12. I drove it for a couple of years and tried to fix it when I was 14. Vehicle went to the junkyard when I was 16.

My Grandpa was not a "fun" guy (very serious type with little sense of humor and old-fashioned) but he never ever treated me like a little kid. If I thought I could do something he would let me try it (like driving or building stuff or putting shingles on buildings, or working with farm equipment) and he would take the time to show me how to do things. Drove my Mom crazy because he never would ask her before exposing her baby to danger starting when I was about 8 years old! And I was certainly game for doing new stuff. Eventually she figured out that he really didn't care what she thought and that I wasn't going to be happy sitting inside the house playing with toys. My Grandpa really had a big positive impact in who I eventually became. I think he was a pretty special man.

Good luck on your repairs

First make sure that none of the int. and exh. cam lobes on the offending cylinders aren't excessively worn (just compare them with the known good cyls by eye).

Second, these engine are known to have 2 very different valve lash adjustment procedures depending on the rocker arm and stud designs (regardless of the VIN #). One type simply requires that you torque the rocker nuts down to 20 ft.lbs, while the other requires that you take each cyl. to TDC (both valves closed) and then tighten the rocker nuts until there is zero lash (slight drag on the push rods while turning/twisting them by hand), followed by tightening the nuts a further 3/4 of turn. You'll need to search this forum, and/or the net, in order to determine exactly which rocker and rocker stud type you have.

Btw, this issue of different valve lash adjusting procedures has stumped many mechanics...

Please don't confuse him again. I've spent 4 pages convincing him that he does have the non-adjustable rockers found on ALL 1996+ vin W 4.3 motors - and that means ALL 1996+ Blazers. The reason his valve train is screwed up is because he tried to adjust them. As a second point, if you have factory screw in rocker studs in a 4.3 (which he does) - then you have non-adjustable rockers. Only press-in studs were adjustable.

Lysmyer is right, I have the screw in, non adjustable studs. There is no valve lash adjustment, just torque it to 20 lbs after the nut bottoms out. Setting all your cylinders may be a good try but I've tried that already. I believe my studs are damaged like Lysmyer says...I appreciate your input though.

Again, not all '96 W vin 4.3 engines have screw in studs (regardless of what some of the various service manuals state). The vast majority are screw in, but a small number went out in '96 with a W vin while having pressed in studs.

If there is a 'hex' on the stud were it bottoms into the head, then they are screw in. If not, they are pressed in.

Unfortunately, bent valves could also be the problem. However, this often results in bent push rods as well. A 'spin' test of the rods while they're installed will usually show if they're badly bent (otherwise, you can, of course, remove them and roll them on a flat surface). Meanwhile, a leak down test might good idea at this point (if you haven't done so already).

Also consider that the cam may have jumped timing due to worn sprockets and/or a worn cam chain.