1971 C-10 knocking sound and not reving past 3000 RPM

[aruss99]

Well that sure is a shame, looks like it makes sense to put a performance cam in with a new valve train. Think about a 268H. Thanks for all the help. I would have never know what to check, it is very much appreciated

[GASoline71]

A wiped cam lobe is a complete teardown and overhaul. There will be so much metal particulate in the oil that it has gone through the entire engine. It will be embedded in the bearings too.

You HAVE to get all the metal particles out of the engine. Meaning a very very thorough cleaning of all the oil galleries. I wouldn't be surprised if there is a bit of damage done to the crankshaft as well. Depends on how long you've been driving it this way.

Not bring the doom and gloom, but it happened to me as well. If you just huck a new cam and lifter in there... you'll be going through this whole process again very soon.

Gary

[BugzC10]

Check that lifter before you go off the deep end with a complete tear down and new cam.

[aruss99]

Originally Posted by BugzC10

Check that lifter before you go off the deep end with a complete tear down and new cam.

Ok, to check the lifter, can I just pull it out? Or is there more to it? Also, if the lifter is messed up, can I replace just that one? Or do I need to replace them all?

[GASoline71]

Like Bugz said... check to make sure it's not a "collapsed" lifter. You can just pull it out of it's bore. But if you pull it and the bottom is eaten away like this:



Then you have worn cam lobes and there will be lots of trash in the oil.

Gary

[67 chevelle]

You need to remove the intake manifold to get to the lifters on a small block , check to see if the pushrod is bent or the rocker stud is lose first , either can cause this

not changing the oil will cause flat cam lobes

[aruss99]

Originally Posted by 67 chevelle

You need to remove the intake manifold to get to the lifters on a small block , check to see if the pushrod is bent or the rocker stud is lose first , either can cause this

Ok, will do. Thanks for the help

[BugzC10]

Originally Posted by aruss99

Ok, to check the lifter, can I just pull it out? Or is there more to it? Also, if the lifter is messed up, can I replace just that one? Or do I need to replace them all?

If you get lucky and it's just the lifter, it is my understanding you should replace all of the lifters. There's also a school of thought that you must put in a new cam along with the new lifters. Pull the rocker arm off the bad lifter and pull out the push rod to see if it is bent.

[motorcritter]

it sounds like it's 'time' to look at the innards. A 40+ year old truck probably needs some sort of attention, more involved than plugs and an oil change. Unless I have definite history on a vehicle, I assume the worst possible maintainence has been done, and inspect accordingly. If the 'worst case scenario' doesn't present itself, I am one happy SOB. If you don't think you're up to the challenge, there's plenty of help, here on the board. There is probably no situation that some one of us hasn't dealt with, and overcome, usually successfully!
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[aruss99]

Originally Posted by BugzC10

If you get lucky and it's just the lifter, it is my understanding you should replace all of the lifters. There's also a school of thought that you must put in a new cam along with the new lifters. Pull the rocker arm off the bad lifter and pull out the push rod to see if it is bent.

In order to take off the manifold, it looks like I need to pull out the distributor as well. Is there any special procedure to take it out so I don't mess it up, or can I just mark it and the intake manifold as a reference to put it back in?

[BugzC10]

Originally Posted by aruss99

In order to take off the manifold, it looks like I need to pull out the distributor as well. Is there any special procedure to take it out so I don't mess it up, or can I just mark it and the intake manifold as a reference to put it back in?

I usually rotate the engine until the dizzy is in #1 firing position (rotor is pointing at #1 cylinder) then mark location.

[aruss99]

I was finally able to pull the cam out of the motor only to find that several of the exhaust camshaft lobes were going flat if not there already. It is so bad that the whole motor would need to be rebuilt. That's where I have a question, my dad is currently building a 62 C-10 with a 6.0 liter LQ4 that he got for around $1000. I have been looking at 5.3 liters and it looks like they are around $600. I know it would be cheaper to rebuild my engine myself and have some of the motor machined than having to buy lots of different miscellaneous parts for the 5.3 but I was wondering what you guys thought of going the 5.3 route for increased reliability and better gas milage. Any input is very much appreciated as I have done a lot of research on this but still wasn't sure the correct route to go given my situation. Thanks

[MARKDTN]

Fuel injection swaps are quite nice. That is definitely the direction I would go. No way I ever build another carbed engine unless it is on lawn equipment.

[motorcritter]

I, too, have decided- no more carburettors, unless it's a vintage motorcycle. The '69 GMC is getting a TPI SBC, the '71 Cheyenne is getting an LS and the jury's still out on the '70 C10. I love the 'old stuff', but I am not a stranger to technology. For a truck that's going to see regular/daily driver use, an LS conversion makes sense, the expense is going to be there, either way- and the 'old tech' stuff has maintainence costs that the 'new tech' stuff doesn't. I vote- LS! I was fortunate (or cursed) to have been in the auto service biz from the time of points and drum brakes and carburettors to all this high- tech (and reliable) stuff. And I am grateful for that.
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[hamjet]

Hey now fellers, carbs go with manual brakes and manual steering! OLD SCHOOL ALL THE WAY!!!

[motorcritter]

Old skool is nice, I've got a '35 Plymouth PJ than is all original except paint colour. Daily driver- no. My '72 Triumph Bonneville is 'old skool', except for the transitorised ignition, gel battery and resleeved Amal carbs. I'm not going to go across country on it, though. The trucks will get used regularly, and so, concessions to modernity will be made. That's how I roll. Or eye roll, 😈
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