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 Post subject: push rod trouble HELP
PostPosted: Fri Sep 25, 2015 9:57 am 
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3 Deuce Weber

Joined: Thu Apr 16, 2015 1:40 pm
Posts: 57
Location: United States
Car Model:
Got it all put together ran for miles

Started next morning, ran real rough. Pulled valve cover and discovered
that several push rods slipped out from under the rocker!

What would cause that?
I put them back and readjusted the valves and ran it for a day just to find the same thing. Am I not adjusting the valves tight enough?
The head has been rebuilt with new guides and seats. Seems to be fine otherwise.

Help

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 Post subject:
PostPosted: Fri Sep 25, 2015 10:31 am 
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Turbo Slant 6
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Joined: Sat Sep 13, 2014 8:25 am
Posts: 797
Location: Rio Rancho, NM
Car Model: Highly Modified Chevy S10 Race Truck
Valves too tight in the guides and sticking open?

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 Post subject: valves
PostPosted: Fri Sep 25, 2015 4:36 pm 
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3 Deuce Weber

Joined: Thu Apr 16, 2015 1:40 pm
Posts: 57
Location: United States
Car Model:
After thinking it through, that's about all it could be. I guess the cure is tearing the head back down and running a ream in the guides. I will look and see how many popped out this time. The funny thing is it started fine this morning cold, then became rough. After driving it for 20 miles yesterday with no problem.

Going to pull the whole motor while I am at it and clean the engine bay and replace any leaking gaskets and seals.

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 Post subject: cure? I am at a loss
PostPosted: Sat Sep 26, 2015 8:01 am 
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3 Deuce Weber

Joined: Thu Apr 16, 2015 1:40 pm
Posts: 57
Location: United States
Car Model:
Is it the machine work that's the problem? The guy that did the work is really good. What besides the machine work would cause the valves to stick. Everything is clean and oiled up when I pop the cover.

I put the rods back and adjust them and it runs like a sewing machine.

I thought of pulling the head and soaking the valves with MMO.

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 Post subject:
PostPosted: Sat Sep 26, 2015 1:24 pm 
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Turbo EFI

Joined: Tue Jan 06, 2004 11:21 pm
Posts: 1391
Location: long beach ca
Car Model:
Sure sounds like too tight valve guides.


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 Post subject: progress
PostPosted: Wed Sep 30, 2015 6:56 pm 
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3 Deuce Weber

Joined: Thu Apr 16, 2015 1:40 pm
Posts: 57
Location: United States
Car Model:
Bought 9.5 mm hone, going to hone all the guides and reassemble with new head gasket and manifold gasket, new manifold studs and nuts.
Using an good gasket sealer on the head gasket (Copper spray), sealer on the studs. Hoping to solve the leak toward the back side.

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 Post subject:
PostPosted: Thu Oct 01, 2015 1:24 pm 
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Turbo EFI

Joined: Sat Feb 20, 2010 10:23 am
Posts: 1341
Location: N. Ga.
Car Model: 64 Valiant
Valves don't stick and then unstick themselves and then stick again. If you were questioning the valve adjustment not being tight enough, the valvetrain would be very noisy. Was it? Before you inadvertently begin honing the guides, you should give the guy that rebuilt the head the opportunity to inspect and re-measure everything with his precision measuring equipment to help resolve the problem. A hone in the wrong hands is a dangerous tool, and you can do more damage than good if you aren't experienced in using one. Especially if you don't have adequate measuring equipment yourself to see and know what you did.

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 Post subject:
PostPosted: Thu Oct 01, 2015 3:24 pm 
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Board Sponsor & SL6 Racer
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Joined: Fri Nov 08, 2002 4:48 pm
Posts: 5835
Location: Burton BC canada
Car Model:
If the adjusters are loose in the rockers they can back off fairly quickly.

Squish the rocker in a vice or use half nuts for a lock.

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 Post subject: Figured it out.
PostPosted: Thu Oct 01, 2015 5:00 pm 
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3 Deuce Weber

Joined: Thu Apr 16, 2015 1:40 pm
Posts: 57
Location: United States
Car Model:
I assumed the previous owner took care of the 25 year old gas since he drove it a couple of months before overheating it.

Well I took the head off and began cleaning the valves and checking the tolerances. There was this black coating on the seats and exposed parts of the valve stem. I could clean it fairly easy and then the valve would slide in and out of the guide freely with no slop.

I now plan to drain the tank and put fresh gas in along with some kind of additive cleaner.

Even though I filled the tank up when I first got it running I should have just drained it in the first place I am assuming there was enough stuff in the tank to burn into this black coating that was on the valves. Mostly the exhaust valves.

I hope I am right.

While I am at it I am replacing the manifold studs and nuts, of course head and exhaust gaskets. I will adjust the valves cold at first, then do it again after it is hot and running.

All I did with the hone was lay in a new cross hatch pattern as the hone was about .001 larger than the guide itself. Basically cleaned the crap of of it.
Nothing is wrong with the adjusters

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 Post subject:
PostPosted: Thu Oct 01, 2015 7:17 pm 
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Board Sponsor
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Joined: Sat Feb 08, 2003 2:37 pm
Posts: 4194
Location: CA
Car Model:
Put a straight edge to the rods to make sure they aren't bent.

Do you know if any material was shaved off the head or block? The pushrods may be too long if so. Check the angle at full valve opening and see how close the cup is to the arm.


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 Post subject:
PostPosted: Fri Oct 02, 2015 5:15 am 
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3 Deuce Weber

Joined: Thu Apr 16, 2015 1:40 pm
Posts: 57
Location: United States
Car Model:
Rods are not bent. The car ran great for 20-30 miles or more before gumming up. I will check the rocker angle but it was strange that the pushrods that slipped out would not go back unless I loosened the rocker assembly. Anyway after I finish getting the black stuff off and clean the gas from the fuel system I hope to be ok.

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 Post subject:
PostPosted: Sat Oct 03, 2015 4:01 am 
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TBI Slant 6
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Joined: Fri Sep 21, 2012 1:49 pm
Posts: 109
Location: murwillumbah,NSW,Australia
Car Model:
Just a few guesses
Weak or broken or wrong length valve springs.
Valves sticking
rocker adjustment nuts loosening because pushrods too long or not enough friction on threads

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 Post subject:
PostPosted: Tue Oct 06, 2015 7:23 pm 
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3 Deuce Weber

Joined: Thu Apr 16, 2015 1:40 pm
Posts: 57
Location: United States
Car Model:
so far I pulled the springs and lightly honed the guides. There was black goop glazed on the exposed parts of the valves and on the seats so I cleaned the stuff off the valve heads and ports with acetone, it came off with that. Hand lapped the valves. Haven't put it back together yet because I bought new springs (arriving tomorrow). Cleaned the surfaces around the valves and plugs.

Rods are not bent. adjusters are perfect

What I still plan to do:
Drain gas, rebuild carb, change gas filter
put the new manifold studs and nuts in as well

just plugging along- the end is in sight!

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 Post subject:
PostPosted: Fri Oct 09, 2015 8:41 am 
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3 Deuce Weber

Joined: Thu Apr 16, 2015 1:40 pm
Posts: 57
Location: United States
Car Model:
I saw that someone referred to my thread and said apparently the rods were falling loose on their own over night. Not the case. The valves apparently got sticky as they cooled, because after starting the next day the engine began to run rough. I popped the valve cover and saw that some push rods had popped out from under the rocker. Not bent, just not under the rocker.

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 Post subject:
PostPosted: Tue Oct 13, 2015 3:03 pm 
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3 Deuce Weber

Joined: Thu Apr 16, 2015 1:40 pm
Posts: 57
Location: United States
Car Model:
hope to have it all together by friday and I will report my results. siphoned gas out and it got ugly, also cranked it over with gasline in bucket and the worse crud i have ever seen came out . cranked it till clear gas.

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