help - i screwed up on my v8 - advice needed Options

[r_towle]

Provided everything turns with no binding once you replace the push rod you should do a compression test before you assemble the intake.
You are looking for that cylinder to be zero or really different from the others .

If you pass that test you may have dodged the bullet of a bent valve

[JeffBowlsby]

Please remove the profanity from your title. It's offensive.

[Bulldog9]

Please remove the profanity from your title. It's offensive.

lol funny guy......

[whitetwinturbo]

Time to upgrade?

[0396]

any local mechanic should be able to help diagnose that....
Its a chevy v8....so look for an older guy that works on trucks ...they know.

rich

Excellent advice, it's a Chevy V8.

[dwillouby]

Lots of good advice here. Get new pushrod and install Adj valve lash at BDC. Tighten rocketr nut while spinning pushrod with fingers. Stop when resistance is felt . Turn 1/4 additional turn . That is 0 lash.Crank the motor over while watching rocker arms. If the cam is wiped you will see little movement in that rocker arm. Cams are damaged by incorrect break in procedures. If all looks good do compression test. These motors are tough not like the little toy motors the car came with (IMG:style_emoticons/default/smile.gif)

[jimkelly]

compression test of cylinder in question #4. the jump to 60psi is with coil wire still on dist cap. i then removed coil wire to dist cap and cranked it again. tried to rent comp tester from advance but they don't do that at my closest store. so I bought one for $29. seems a v8 spark plug is 14mm, go figure.


https://www.youtube.com/watch?v=rnZkafToHug

[JOEPROPER]

It's an old Chevy... Put a push rod in, adjust the valve and put it back together.

[Justinp71]

compression test of cylinder in question #4. the jump to 60psi is with coil wire still on dist cap. i then removed coil wire to dist cap and cranked it again. tried to rent comp tester from advance but they don't do that at my closest store. so I bought one for $29. seems a v8 spark plug is 14mm, go figure.


https://www.youtube.com/watch?v=rnZkafToHug

Make sure you have the throttle wide open on the compression test, if its closed the piston does not suck enough air. Compression seems like it could be ok, I would check an adjacent cylinder to see how it compares, to give you a base line.

Also as others have said make sure you install the new push rod correctly. Solid or hydraulic cam? Hydraulic cams have no valve lash setting.

Are you running all stock components (heads, rockers, springs). Sometimes after market valve train components will need custom length push rods.

Do you think your noise could be lifter tap? or do you hear more of a 'knock'?

[Bulldog9]

compression test of cylinder in question #4. the jump to 60psi is with coil wire still on dist cap. i then removed coil wire to dist cap and cranked it again. tried to rent comp tester from advance but they don't do that at my closest store. so I bought one for $29. seems a v8 spark plug is 14mm, go figure.


https://www.youtube.com/watch?v=rnZkafToHug

You need to compare that reading with other cyls. I haven't checked compression on a GM SB in years, but I seem to remember 90 was perfect, 60 or below not healthy. You should kill power to the coil and fuel pump for this. Also, make sure you are checking the compression with throttle wide open.

[Justinp71]

[/quote]

You need to compare that reading with other cyls. I haven't checked compression on a GM SB in years, but I seem to remember 90 was perfect, 60 or below not healthy. You should kill power to the coil and fuel pump for this. Also, make sure you are checking the compression with throttle wide open.
[/quote]

Yeah kill the power to the coil, I once just pulled the main wire off the coil and it zapped to its own power feed wires and fried the coil! on top of that it was a computer car and fried the dang ECU!! (IMG:style_emoticons/default/headbang.gif)

[ThePaintedMan]

I know you're learning... but just FYI.. that's not typically how one would do a compression test. As others said, you don't want that thing firing up (as it almost did). Kill the power to the coil and turn it over several times with the throttle wide open. On a /4, it would be easier to just pull all the spark plugs to allow the engine to crank over nice and easy without compression in each cylinder. On a V8, you'll just leave them in, but it will crank slow.

I believe you'll have a different reading than you're seeing currently with a couple more revolutions of the engine. Keep at it, you're on the right track...

[veekry9]

It's an old Chevy... Put a push rod in, adjust the valve and put it back together.

Yep.
(IMG:style_emoticons/default/smile.gif)
If it blows,a near new wrecker is available for less than 1K.
Almost as disposable as shoprags.
One other thing,be certain the pressed in rocker stud was not damaged,inspect the rocker's bowl and stud's ball,make sure the rocker's face is not marred.
These stamped rockers can bend in some interference circumstances.
If the cylinder will hold air,screw in an airhose plughole adapter and release the spring keepers.
Don't lose them,use a magnet,or rag to keep them from falling.
Make certain the cylinder is at TDC,you don't want the valve to fall into the hole.
You can now check the run-out and clearance of the valvestem.
With 0.0025" wiggle or runout,the max wear has been reached.
With a worn guide and poor seals,the engine will blow blue smoke and foul plugs.
A scope of the piston top will show heavy carbon buildup.
Once you find the heads beat,check the shortblock's bottom end.
A new set of heads is on the getlist,because the aluminums are cheap enough.
Check your local craigslist,they're hot commodities.
Have fun,it doesn't get cheaper than this.
(IMG:style_emoticons/default/biggrin.gif)

[bretth]

As others have said, disable ignition and fuel pump. Then keep the throttle wide open while cranking. You need to crank motor about 4 times and see the psi then. Also notice roughly how high the compression climbs on each crank compared to other cylinders. I would also remove all of the spark plugs during testing for most accurate reading. Good luck.

Brett

[Bruce Hinds]

I don't know why you all keep talking about a bent valve. That doesn't seem likely. He didn't have any backfiring so the valves would be closed just fine.

He put in too long a bolt that interfered with the push rod. Metal in the oil, change it. Check the lifter and take a look at the cam lobe for excessive wear. I doubt you have much of a problem.

[jimkelly]

thanks guys for all the great advice. I am taking my car to rightpedal's place on sunday to button it up, provided we don't find anything new. tomorrow I plan to drain the oil, look for metal in it, and will redo the compression test. thanks again (IMG:style_emoticons/default/smile.gif)

[whitetwinturbo]

Drag a big time magnet through the old oil to find metal. Cut the oil filter open to find same! (IMG:style_emoticons/default/beer.gif)

[Cairo94507]

Good tip. Best wishes.

[veekry9]

If it all goes bad,here is a cheep way out:
https://delaware.craigslist.org/pts/5399241755.html
(IMG:style_emoticons/default/smile.gif)

[jimkelly]

those are good deals but I need a pre 1986 engine as my renegade stuff is for pre 1986 I think? hopefully I won't need a new engine this time around. i'd also prefer to get going on my 1975 suby conversion project for when gas prices go up again.

http://www.renegadehybrids.com/914/SBC/SBC.html

ok, drained my oil and removed filter. checked removed oil with a small magnet and felt like I did not find any metal in it. pic of drained pan that I should have cleaned very thoroughly before draining my oil into it.


https://www.youtube.com/watch?v=luRqmw2sd14