Chevy 350 valves/lifters

Sorry for a tow vehicle question in this forum, but it seemed appropriate.

I blew a head gasket in my '96 Chevy 350 K-1500. Got water in the oil, and it turned pretty thick. I tore it all down and replaced both head gaskets. With it all back together, I have no compression - valves are open.

The book says tighten the rocker until the pushrod tensions, then another 3/4 turn - the valve should still be closed. I've loosened the rockers, put air pressure in through the spark plug hole, and start tightening. The valve opens after 1/4 turn.

I don't know that much about lifters, but I wonder if the gooey oil has screwed them up so they don't have the correct compliance, forcing the valves open early.

I'm considering my options, and here's my list:
1) Leave the rockers loose, hope it starts, and hope the goo pumps out of the lifters. Then adjust them properly.
2) Take the intake back off, take the lifters apart and clean them (don't know if this is possible).
3) Buy new lifters (don't know what this costs).

If option 1 is feasible, can/should I run it with the valve covers off?

Comments?

Thanks,

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Marty Doane
ITS RX-7 #13
CenDiv WMR

If I hear you correctly, it sounds like the lifters are too big? The valve is being opened when it shouldn't be. Provided this is correct, read on. If I've missed your description sorry, I have no idea.

Some hydraulic lifters (including the ones in my '95 GM) have a spring inside them to help keep them at or near their inflated size when the oil pressure drops. If you take everything apart they can sort of self inflate w/ the spring bigger than they should be. With the oil thick & gooey they stay over inflated and will hold the valve open. IF (big IF) the valves don't hang open to the point of interfering w/ the cylinder tops, I don't see any problem w/ starting the engine, except it will run like crap since it has poor compression. Once the oil circulates a bit, the lifters will compress back to where they should be. Gas engine, should be ok, but check really carefully.

How do I know this? Changed a head on my GM diesel, after it was all together I turned it over w/ a wrench and felt it bind up and could see the rocker move a bit. The valve was getting bumped by the piston top since the lifter had been sitting w/ no valve train to keep it compressed. Take the head off again, pull the lifters out of their little hiding spots, warm them up (toaster oven in the shop sure comes in handy), slowly squeeze them in the vice back to fully compressed size, re-assemble.

Yes you should be able to leave the rockers off while running it, but I would take them off while its running, not start it w/ them off. Plan on some oil getting loose. I've seen V8's get their valve adjustments done while running (pretty cool actually).

Good luck.

Aren't cars so much fun?

***I've seen V8's get their valve adjustments done while running (pretty cool actually).***

Hell, ya ain't adjusted any valves untill ya adjusted a 1948 Plymouth straight 6 with the right front wheel off, siting under the wheel well, with the motor side cover off & all the adjusting with the motor running. Can ya say oil BATH ?

Have Fun http://ITForum.ImprovedTouring.com/wink.gif
David

Thanks for the help. I loosened up all the rockers to just past snug, and it started right up. Let it run for a while, then tried the "book" adjustment again, with only 1/2 turn past snug. Wouldn't run. Loosened them up, then adjusted by sound while it was running. Seems good.

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Marty Doane
ITS RX-7 #13
CenDiv WMR

Engine runs great but I've still got the internal coolant leak. Either I dinged one of the new head gaskets or the block is cracked.

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Marty Doane
ITS RX-7 #13
CenDiv WMR

If the engine overheated it may have cracked the cylinder head. Been there,done that.
You should also check the bearings since anti-freeze in oil does nasty things to bearings.

I had the heads checked by a good shop. Magnafluxed, resurfaced, valves ground, and new seals.

I don't know how to check the bearings without a bottom-end teardown, which I'll postpone until it becomes necessary.

Thanks,

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Marty Doane
ITS RX-7 #13
CenDiv WMR

Marty,

Those motors, as well as the newer Vortec motors are well known for coolant leaks around the intake manifold. I had one of the same motors in my old truck ('89 K1500), and did the head gaskets @ 80k miles. When they went again @ 120k miles, I went w/ a crate motor. My '98 K2500 has had an internal coolant leak since I bought it. I've put 40k miles on it since I've had it, and just keep topping up the coolant. The truck has 150k on it, and when it gets so bad that I have to address it, I'll just drop a crate motor in it (or get rid of it and get a new truck, but probably just swap the motor). Crate motors can be had for ~$1500, and I was looking at a 350hp version from Summit that was ~$2500.

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MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608

Boy do I feed dumb. I've got to stop hiring lame brained mechanics (yours truely). I bought a coolant pressure tester and checked it out. Tested fine. Drove it a while and the water in the exhaust disappeared (must have just been the exhaust full of water). The tiny bubbles in the radiator must have actually been residual Stop-Leak particles (left over from before the repair).

Thanks for all the help,

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Marty Doane
ITS RX-7 #13
CenDiv WMR