kevamg

Please read here to get get the scoop on the situation
https://ls1tech.com/forums/pontiac-firebird-1967-2002/903643-how-can-i-tell-400ci-455ci.html

Ok guys after making many many calls for engine rebuild quotes and getting very expensive quotes of between $1800-$3500 Im starting to look at other options!
Something suddenly made me go out today take the top end apart!

Luckily all those rusty old bolts came out easily without snapping..THANK GOD!

So I remove the intake and block cover to access the rods and cam bearings and I also took out and looked at all 8 pushrods none seemed to look bent!
All were well lurbricated and filled with oil. I took out the bearings that sit on the cam and they all looked ok..I guess. What other signs should I be looking for on the cam lobe surfaces??

Anyone have the
1. torque specs
2. ignition wiring order
3. Best spark plugs to use
4. Best oil to use
for a Pontiac 455?Lol

Everything looks fine and well lubed..but something was definitely clacking in there.Like I said in the first thread..the car starts and idles fine..it just feels rough like its misfiring and running on 6 or 7 cylinders and it makes clack clack clack sounds!
The passenger side exhaust backfires and putters.. wonder if its ignition problems?
I have enough access to fix any top end problems on my own..but as far as bottom end work I don't have an engine hoist nor a car lift!

What can it be?
What are spun bearing symptoms?
I wonder if all I need is a proper rocker arm relashing?
Should I replace the rods and cam bearings anyway?Roller rockers maybe while Im at it?
How do you know you have a spun bearing?
Are my plug wires routed to the right cylinders?


Well good thing about this is that Ive gained alot of confidence in doing repairs on my own I getting a good hands on experience feel for how our pushrod engines operate..I looked down at my cam and realized how easily I could do these performance upgrades myself and not have to pay a damn mechanic shop $60/hour labor rates!

So here are my options! If the problems still persist after I put the motor back together with .....
new plugs and wires
oil
relashed rocker arms
new rods and cam bearings
new gaskets

I can..........

Spend $1800-$3500 on a rebuild if it is indeed a bottom end crank/piston rod spun bearing problem.

------OR------

Have someone yank the rest of the engine for me and spend $1800-$3500 on a used maybe even meaner better 400-455 engine from Ebay/here/other forums/online merchants.Then have someone install the new engine for me.



Ill post detailed pics of everything as soon as I can, maybe you guys can tell if my heads and cams are stock or not..and maybe what year 455 I have.

IRONFIST

I'm glad you're having fun and learning some stuff while you're at it! I learned everything I know about building engines by taking apart V8's just like you're doing right now. I don't have my shop manual on me right now, so I don't want to post torque values off the top of my head without checking, I'll give you actual values tomorrow.

You'll notice the cam isn't so hard to swap out on these cars, if you just undo that waterpump/timing cover assembly the cam slides right out the front. Easy stuff...

Now, by cam bearings I think you mean lifters? The actual bearings for the cam are pressed into the block and rarely go bad... doubt thats your problem. What you should do now is go get yourself some new lifters, see if that fixes your problem.

I've spun more then my fair share of rod bearings, and the one thing I'll always find is tiny flakes of metal floating in the oil. If you want to know if its a spun bearing, drain out some oil, if it has tiny flakes of silver in it (like metallic paint), then you got a bearing problem. First thing you should do today, is check the oil for metal... if thats not it, then you have ruled out the worst possible scenario.

30thanniv

iTrader: (2)

Dude, no offense but I have serious concerns about your analysis. You say you took out all 8 pushrods, make sure you don't miss the other 8

I highly doubt you took out the cam bearings, but if you did your fucked.
You are going to have to pull the engine to install new ones. It requires a special tool .

What kind of oil psi are you seeing at idle?
Where is the clack clack clack coming from.
It could simply be a worn rocker arm.

Do yourself a favor and find a buddy who knows a little more about cars then you do.

I always say a little bit of knowledge is a dangerous thing.

1fastWS6

iTrader: (3)

Lol....a bit of knowlege -and- alot of tools IS a dangerous thing! True!

I think he means lifters when he's referring to the 'cam bearings'. I'd guess its just a simple rocker out of adjustment / bad rocker arm thats making noise. If its bad enough it could be causing the cylinder mis-fire that you think your hearing also. You probably took apart way more stuff that you needed to but hey, thats how you learn. Keep in mind though that sometimes $60/hr can be money well spent when you mess with stuff yourself and ultimately cause $100's or $1000's in damage to the engine. Finding a buddy to help you out is good advice.

Oh, and BTW, everything you took apart thus far has absolutely nothing to do with the rod bearings or is even remotely close to them if thats your suspected problem. Cut the oil filter open and see if there's metal in there, that'd atleast be a start in the right direction.

Craig

cerino2000

iTrader: (1)

Just read your other thread. A couple things come to mind. First off, you said that it really pulls on the top end! that's great but what is your history with Pontiacs? The reason I ask is one of the main ways Pontiacs die is because a small block guy who is used to rapping the RPMS gets behind the wheel and thinks they can do that do a pontiac. If it is a 455 (you still haven't clarified this) the most you should feel comfortable revving it on a regular basis is about 5500 RPM. Trying pushing it farther than that, and on a regular basis with a stock built engine, and it will start knocking. So is it possible this is what happened? Did you run it up to high?

Secondly, Pontiac factory rocker arms get torqued to 20 ft lbs. Period. You do need to make sure the cam is off the lobe for each of valves you are adjusting. The fact that you have a rapping sound and a backfire does lead me to believe that you have a valve issue that could be as simple as one of the rocker arms backed off. However, not to make your day worse, there has been an onslought of cams getting their lobes knocked off which would cause all of the symptoms that you described. There is much debate on why it happens but the root cause is in fact the lack of Zinc in modern oils. Because of this, special precautions have to happen to prevent the lobes from being knocked off. A lot of people don't know this or are just to lazy to do it. The engine runs fine for a while, the lobe goes, and then their car starts doing what yours is doing. If you have a lobe issue, you would be able to see it while the car is running with the valve cover off.

For a rod knock, give me a few and I'll see if I can find a vid of the one and only time I spanked a bearing.

cerino2000

iTrader: (1)

Here's a vid of my car when I was diagnosing the rod knock. And this mother was spanked really bad too once I got it apart. The rapping you hear is what a rod knock sounds like. Notice how it is most evident under a float condition while driving and under very mild revving when in park.

Right click here and save file/target as.

cerino2000

iTrader: (1)

Here's an in-car vid about 10 minutes before the video above was made. These engines will make some serious power. Comp XE276 was in the engine with 6X heads on top. This car had 2.41 *** end too so when you hear it shifting from first to second, it's doing about 80mph.

Right click and save target as.

kevamg

Ohh no engine doesnt sound anything like that!Sounds like someone beating the valve cover with a spoon!

Formula350

iTrader: (3)

You might have a collapsed valve spring...