| Slant Six Forum https://slantsix.org/forum/ |
|
| push rod trouble HELP https://slantsix.org/forum/viewtopic.php?t=58412 |
Page 1 of 1 |
| Author: | Hapster [ Fri Sep 25, 2015 9:57 am ] |
| Post subject: | push rod trouble HELP |
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 |
|
| Author: | ProCycle [ Fri Sep 25, 2015 10:31 am ] |
| Post subject: | |
Valves too tight in the guides and sticking open? |
|
| Author: | Hapster [ Fri Sep 25, 2015 4:36 pm ] |
| Post subject: | valves |
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. |
|
| Author: | Hapster [ Sat Sep 26, 2015 8:01 am ] |
| Post subject: | cure? I am at a loss |
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. |
|
| Author: | madmax/6 [ Sat Sep 26, 2015 1:24 pm ] |
| Post subject: | |
Sure sounds like too tight valve guides. |
|
| Author: | Hapster [ Wed Sep 30, 2015 6:56 pm ] |
| Post subject: | progress |
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. |
|
| Author: | CNC-Dude [ Thu Oct 01, 2015 1:24 pm ] |
| Post subject: | |
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. |
|
| Author: | sandy in BC [ Thu Oct 01, 2015 3:24 pm ] |
| Post subject: | |
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. |
|
| Author: | Hapster [ Thu Oct 01, 2015 5:00 pm ] |
| Post subject: | Figured it out. |
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 |
|
| Author: | Pierre [ Thu Oct 01, 2015 7:17 pm ] |
| Post subject: | |
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. |
|
| Author: | Hapster [ Fri Oct 02, 2015 5:15 am ] |
| Post subject: | |
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. |
|
| Author: | slantsik [ Sat Oct 03, 2015 4:01 am ] |
| Post subject: | |
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 |
|
| Author: | Hapster [ Tue Oct 06, 2015 7:23 pm ] |
| Post subject: | |
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! |
|
| Author: | Hapster [ Fri Oct 09, 2015 8:41 am ] |
| Post subject: | |
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. |
|
| Author: | Hapster [ Tue Oct 13, 2015 3:03 pm ] |
| Post subject: | |
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. |
|
| Page 1 of 1 | All times are UTC-08:00 |
| Powered by phpBB® Forum Software © phpBB Limited https://www.phpbb.com/ |
|