The Stovebolt Site Forums The Shop Area Engine Shop need help please

everything was great with my 235 after the rebuild running great great oil pressure(40lb), went out to day , just sitting there idling, it started to mis, go home and pulled off the #1 plug wire no change in running ,,, so i thought it must be that cyl so i changed wire no help,, change plug no help , i took the wire off and checked it is firing i saw spark at the plug and at the cap , what could it be , or you know what i can check ???

thanks

Check the compression in that cylinder. Is it making any noise when its running?

update
took valve cover off found a broken push-rod, i took the side panel off took the lifter out looks fine so i am going to replace all 12 ,, i should have done that on rebuild , those are the only thing used on the total motor .. live and learn the hard way ( my way ) ,, wheres a good place to get push-rods now

thanks guys

Make sure you get push rods to match the year of your 235. Measure the length of yours and call to be sure the replacement push rods match that length.

http://www.kanter.com/p18-chn.html

http://www.egge.com/site/?d=48&dt=1&SubCategoryId=21

http://www.vapinc.com/chevy/Valves%20and%20Parts/main.html

Rockauto.com has them at good prices for some years.

Oh yeah, why do you think your engine bent a push rod?

Did you have the head rebuilt?

What was done, if anything, to the valve guides and valve seals?

I think he said he had a broken pushrod?

Oh yeah, why do you think your engine broke a push rod?

i dont know its was the original rods ,, could of have a crack in it before ,, got i was able to get a large pcs the rest fell to the bottom of oil pan i guess i am going to change oil also ,, i did have the head redone too , it was the second back

I think what Tim is concerned about is a stuck valve.
Push rods do not usually bend or break unless a valve sticks.

Is the way i can check it?

Pry down on the valve using a screwdriver or pry bar. Check a couple of working ones so you get a feel for how much it takes to move the valve. Sticking valves should also be lower then the rest of them, site down the line and look for one shorter then the others. While you are there, look all around the valve spring, you are looking for a broken coil, that usually won't break pushrods, but it never hurts to really look it over.

Joe

I was thinking when i had the head worked over he did replace spings forgot what ones maybe exhaust ? could be combation of new springs and old push rod it was the second back from front, ,

When you had the head rebuilt, what was done, if anything, to the valve guides? Were they replaced, were they knurled, or were they left as they were?

As Dave posted above, something has to give if you have sticking valves. Push rods are the weakest link and they are the first thing to bend/break if you have sticking valves.

i dont remember right now ,, i know he did spring work ,, and guides and sets maybe ,, it was 300 bucks ,, could have been old push rods ??
like i said everything was great i drove it for a little while ,,maybe too tight i would have thought if too tight i would have a mis???

Most likely the guides are too tight. When the engine warmed up, the valve seized in the guide. About the only reason these old engines bend a pushrod.

I have reused countless pushrods providing they were still straight and didn't show signs of wear.

Did you adjust the valves when you put motor back together? Did you re-adjust after getting it running?

My original head was done over at a machine shop. It turned out later down the road I discovered it was using antifreeze. One of my valves eventually stuck open a little. There was a crack near the exhaust valve that was allowing antifreeze in to the combustion chamber. Some of it got in a valve guide and made it sticky. My guides were also worn really badly.

If you look at the top of your head, the exhaust valves are on more of an angle then the intakes. Also you can see how they are positioned to feed the intake and exhaust manifolds.

don i did both i adjusted them at first to get running and then did it again after hot while running ,, i hope they are just old ,, i had lifter trouble at first , i tried to adjust them tring to get the noise out with no luck, soooo. got me , i am ordering all new ones tomm and change oil ,,,,,
1 things more , is there anything i can do to make the oil pan magnetic so it would attract all metal , i know there i can get magnetic plug
thanks

How old is the fuel in your tank? Old fuel will seize valves.

not old i am a diver i love to drive this thing ,, it wont have time to get old , if it ant raining i am driving

merry christmas guys

Did the machine shop replace the valve guides? Or did they knurl them?
If you can look at the invoice for the machine shop and let us know what they did to your head. We can maybe give you some better help then.

ok i will thanks


merry christmas ,, i like say it sorry

If the adjusting screw and lock nut were not tight, adjusting screw could back off enough to allow push rod to get off center. which could cause bent or broken push rod.I didn't properly tighten rocker arm assembly after replacing bent push rod. engine ran fine then the nuts loosened and started missing. luckily caught it before any damage was done. Got in too big a hurry.

Very good point i have adjusted these things several times, and that could be the trouble, ,
Thanks

Merrry christmas

You said you have good oil pressure, do you have oil at the pumping to the head/rockers?

Yeah i have good oil pressure everwere now after the rebuild, , i like after you turn off the motor, you can hear the oil draining back down, , so i know there is oil there,, i feel now that maybe the lock nut came off causeing the screw to back off ,, like the guy said, ,,, i dont know, ,, i hope that what happen lol

Well i got my push rods in, i did what the book said 1 1/2 turn past 0 and they was too tight so i back them off a little , its better but still seems off in timming i reved it up and it back fired so could they be still too tight, ,, if so how muck do tighten them down, , i do have hyd lifters,,,, and could too tight lifters cause timing to be off i didnt mis with the timing at all, ,, it will start but not like it did

Thanks

If it was mine I would get the engine warmed up. Take the valve cover off and turn the idle down. The one at a time, loosen the nut until you hear it tapping, then slowly tighten it to get it quiet. Once its quiet turn it another 3/4 of a turn. Do this to each one and you should be good to go.

Did you do this while the engine was warm?

I don't know too much about the early six hydraulic lifters, but seems they may be too tight.

When I adjusted them I had the engine idling and would back the adjuster screw off until they would "click", then tighten the adjuster screw until the click just stopped, then 3/4 of a turn more.

Never had any problems doing that. But someone who knows better should be along shortly.

i have done it before while running but not this time ,, i did while cold ,, so after the pumped up they would be too tight ??

I would think so, but I figure some one with better knowledge will come along.

And the back fire could have nothing to do with the valves. Could be a plug wire crossed, bad spark plug, bad distributor cap.

If the valves are too tight it will backfire.

well ok i will go back them off another 1/4 turn or so and give it a try , its hard to do it while its running

thanks

I think your making a mistake, do it right. Start it up and adjust them.

everything is good for now , i think we are back to normal , i will take it out for a drive today ,,i hope things go good so i can get back on the window felts and channels

thanks

Don't pay attention to the amount of adjustment, just set them about half of the lifter travel. How to do that is, while the engine is running, loosen the adjusting nut till you hear ticking, then tighten the nut slowly till you hear a miss. It make take a few times to find the point of a miss, but this gives you a idea on how much travel is in the lifter. If you use about half that amount, you will be good to go.

It sounds like you are on the road again, so recheck the rockers in a week or so. If it does it again, then you will know it wasn't your doings.

Joe

thats were i am now ,, i loosen the adjusting screw until i heard the tick then i tighten it down a little ,, it sounds great while hot ,, now this morning i went out and started it , i could could hear the ticking ,, i know it will go away when hot ,, is that the way it was new ??? , or should i tighten when cold ??

thanks

Better listen to Don and Roy. They know what they are talking about. Been done that way for as long as HYD lifters have been around.

Ill have to try it that way, its hard to hold the screwdriver on the screw and turn it whike its going, lol but ill give it a shot

Thanks

Idle the engine down a bit with the idle adjustment screw on the throttle shaft to make it easier to stay on the adjustment screw. Then when done, bring the idle back up. Made it easier for me.