Replacing the Camshaft and bearings

[83Blzr62]

Well my oil pressure is on the low side and I have a tick in the top end near the #8 cylinder, so I think I may change my cam because I used the original '82 cam. I have a few questions. Should I replace all the lifters? They were brand new when I rebuilt the engine 900 miles ago. Who makes a good cam and lifters? The melling one is $270 from autozone and the price goes up to $450 from carquest. Also how do you check the camshaft end play? It is not in my haynes book, so I never did it.

I might also change the main bearings and try to get some with lower clearance because mine were at the high limit. I used King bearings from the Avant Salvage. Are there any recommendations on what I should get?

Thanks,
Kyle

[Robyn]

You really need to find out what is causing the ticking noise before tossing $$$ at the thing.

If the cam has gone away then you will need to replace the lifters.
Rollers are a tad more forgiving than a flat tappet type hydraulic.
I have seen lifters swapped from cam to cam but its not the thing to be doing.

Replace the cam, replace the lifters.

Now another issue is the rocker guide buttons up top.
Did you replace them?
If you have stamped steel rockers they are the little plastic things that keep the rockers on the shaft.

Be sure your low oil pressure is not just a goofy electric gauge, put a regular tube fed gauge on it to test things before getting totally excited.

GM electric gaquges have been known to get flakey and read all over the sky.

Many times its just the sending unit too.

Check it first.

This tick?? are you fairly certain its a lifter? It can be an injector possibly.

Engine run rough? does the noise come and go? does it run at cam speed or crank speed?

A bent pushrod can also cause an issue.

When installing heads on a 6.2/6.5 always have all the pistons away from TDC when bolting the rockers down for the first time.

With pistons at TDC if you bolt the rockers down you can actually stuff a valve into a piston and bend a pushrod during the time it takes for the lifters to bleed down.

Just a few things to think about

Hope it helps ;0)

Robyn

[Robyn]

The end play on the cam is not a real big issue unless the gear and or thrust plate are badly worn.

Something like .005" is probably in the ball park.

The bearings usually run .002-.0035 clearance and even at the high end you will be fine. My 6.5 was on the high end and it runs great pressure.

To check the cam end play use a magnetic based dial indicator on the front of the engine and place the dial probe on the center of the cam bolt.
gently nudge the cam back and forth in its bore.

You will have to have all the lifters off the cam to do this though.
There can be no load on the cam if you hope to get any sort of acurate reading.

Robyn

[john8662]

Roller cams are usually re-usable because of the small amount of wear associated with the rollers on the lifters.

The big deal on the cam is the bearing journal wear. This requires mic'ing just like the journals on the crankshaft.

The ones I've replaced were due to severe scoring or the journal size was too small before or after a polish.

You can re-use the lifters if you've got such low miles on them.

Just inspect them, I prefer ones that HOLD their pressure, where you can't easily push the plunger down with your thumb.

I still think the tick may be the remnant of a glow plug, maybe just drive it?

Not sure on the oil pressure. It's possible it's just a journal size issue, it's also still possible that it's the oil pump itself.

J

[83Blzr62]

I am certian it is not an exhuast leak or glowplug remnant. My glowplugs burnt off in the #7 and #5 piston. Using a stethescope it is obviuosly coming from the #8 cylinder. I amgoing to try to boroscope the cylinders before to besure nothing it hitting them. If I do chnge the cam and lifters I will change the pushords out with new ones. This weekend I will change out the vacuum pump and the hook up a mechanical guage before I do anything. Any recomendation on bearings, lifters and cams in case I have to use a new one? So far I have found sealed power, clevite, and hitech.

thanks,
Kyle

[john8662]

Cam = Clevite
Bearings = Clevite or Fed Mogul (Sealed Power)
Lifters = Sealed Power

Pushrods = GM

Just to name a few :)

Good idea checking the vacuum pump.

ALL of my engines make some kind of odd noise in one way or another, don't know why tho, they're all different too.

Can't tell on my '82 tho, cause it's pretty loud exhaust wise.

J

[83Blzr62]

Okay, thanks for the advice. Yeah I know they make noises, but this one is just too loud and scares me too much to let it go. I hope I can find some wear on something so that I know that it is the cause.

I will telll you what I find.

[gmctd]

As mentioned previously -

If the nylon rocker-arm keepers crumble, the rocker-arm will be off center, allowing extra clearance - pull the valve-cover, check things out first.

Put a mechanical gage on an oil gallery - check the actual pressure B4 you trust the inst cluster - gages, mylar circuit film, connector, and sender are apt to be faulty