Odd engine/valve issue

[cdennisg]

OK, in 25 years of messing with VW's, I have never had this happen.

Some history. I recently hauled home a 69 bus that had been sitting for over ten years. The engine was built some years before that, with approximately 40K miles on it when the bus was parked after a light roll into a snowy ditch. It's an AE case, DP heads, all stock with all of the correct components in place, except for the dreaded 009.

When I got it home, it was missing the distributor, coil, and generator pulley. I replaced those parts, set the points and timing, dumped a little oil in the cylinders, some gas in the float bowl, and turned it over. (I let the oil sit in the cylinders for a couple of days before turning the engine) Before hitting the starter, I turned it over with a wrench to make sure it spun freely, and that nothing was locked up or making noise.

It stumbled a little, then fired off and ran. It ran really nicely. I was quite surprised. It smokes a little, but it is quiet, smooth and revs nicely. The rebuilder is a local mechanic who dynamically balances everything, and you can tell it when you hear them run. I have owned several.

So, I let it run for 20-30 minutes, checking temps and oil pressure, and all was fine. The engine is full flowed with an external cooler and filter. I drop the oil, drop the sump plate, change the external filter, and refill with fresh oil and some Rislone ZDDP additive. I had planned to adjust the valves the next day, but that became a week later. This evening, after a long day at work, I decide to relax by finally adjusting the valves and running the engine again. I learned to do the valve adjustment the set-it-at-TDC#1-then-turn-the-eninge-backwards-180-then-do#2 method back in 1987, and that is what I still do today.

I pop the dist. cap off, turn the engine round to #1, pop off the valve cover, and discover that #1 intake has 1/8" of lash! I double, then triple check that I am in the right place in the rotation, and I definitely have TDC of #1. During this process I find that #1 intake valve has no motion at all. No rocker arm or pushrod movement. # 2 is moving just fine, so I pop off the other valve cover, and discover that #3 intake valve is stuck open, but its pushrod and rocker are moving as normal. There is about 1/4" between the valve stem and the adjuster with the valve obviously stuck open. The #1 Valve is not stuck open, it just has no movement in the pushrod.

I did notice while spinning the engine with the wrench to find TDC #1 initially, that something felt a little odd. Something seemed to bind, and felt a little springy, but I chalked it up to the regular compression felt when turning an engine over. I could be that the #3 intake valve was sticking at that time. Keep in mind, this engine ran great, with no odd knocks, ticks, or bangs in 30 minutes of run time.

So, any ideas WTF is happening? I hope to talk with the engine builder tomorrow, if he is in town. He's a friend of mine, but he is cutting back his shop hours to slow his life down a little bit.

Any help, advice, suggestions, constructive criticism, or random Ben Franklin quotes are much appreciated.

Thanks, Corey
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[modok]

Most stories like that have one thing in common;

the vehicle sat idle for over a year thus causing the gas tank to develop some kind of brown varnishy goop, that glues injectors and valves solid

squirt some penetrating oil or marvel oil in there to help dissolve the goop, and clean out the gas tank man!

[bugguy076]

Pull both of the rocker shafts off and remove the push rods. Looking at the parts as you take them off. Check the valve springs. They may have crushed or broken while sitting. The stuck #3 valve can be tapped on with a hammer and brass punch to loosen it . #1 may have a stuck lifter. Push in on the lifter by pushing in on the push rod to see if it moves. Roll the motor over by hand and repeat pushing in on the rod to see if the lifter is free.
Take your time. Clean the parts up. Check the rockers for free movement on shafts, reassemble and reset valves. A little TLC might save your engine.

[FreeBug]

" An ounce of prevention is worth a pound of cure"

I had this happen, bus sta ten years, ran a couple weeks, the started bending pushrods... Yep, goopy varnish buildup, seized valves. For me, by the time stuff started freezing up, it was too late. Ended up changing the tank, as it would fill filter after filter with junk.

Hope it works out better for you....k.

[cdennisg]

Thanks for the tips. Tank was bone dry. I think they either drained it or the hose was leaking and it drained on it's own.

I'll pull the rocker arms off today and give things a little look-see. I wonder if this is one of those situations where I could try some of that engine flush stuff on the shelf at the FLAPS? Never used it before.

So the theory is that gunk in the oil is causing #3 valve to stick open, and #1 lifter to stick closed. I'll dig into things and report back with my findings. I will not run the engine until I have this figured out. Is it OK to carefully pry on #3 valve spring to get it to close? I will pad the valve cover seat area and use along pry bar.
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[cdennisg]

[modok]

You want to hit the valve guides, you can spray em at the valve cover side and also fog some marvel oil into the intake and maybe even add some marvel oil to the gas tank, but your better off to clean the gas tank pronto

ten years is MORE than enough time for the gas to completely evaporate from the tank, I have known this to happen many times. I do not know the chemistry behind how gasoline turns to brown goop but I am familiar with the quality of said goop It's gooey, like dried caramel

[cdennisg]

I will be removing and cleaning the tank, but how does varnish in the tank cause a lifter to stick? I can understand the intake valve, but a lifter?
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[modok]

Your description of the it running great but then #3 intake working but the #1 not moving does not make sense, they both operate off the same cam lobe, I was just focusing on the sticky valve guide.



It is possible the guide sticking has caused you to bend the #1 intake pushrod, you will soon find out when you next start it

how could the lifter be stuck closed? that's not possible, the pushrod is the weak link, if it sticks the pushrod will bend

[cdennisg]

Yes, I meant that the #1 intake lifter must be stuck open, as the rocker arm does not move while the engine spins. I'm guessing that the pushrod may be bent. I pulled all of the spark plugs and turned the engine over while watching the valve train on both sides. That #1 intake pushrod is just barely pushing against the rocker arm as the cam turns around. There is just a slight pressure right at the top of the cam lobe cycle.

I managed to get that #3 intake valve partly unstuck, by gently prying it out. But it will not come any farther with gentle pressure, and I am reticent to pry any harder. That pushrod is operating as normal, just has the stuck valve.

I am currently cleaning the tank in situ with muratic acid and rinsing with water. I have done this before with good results, so it's worth a try. Nasty stuff in there. I'll be pulling the 1-2 rocker off next to check that pushrod for #1. I'll report back with my findings.I added Sea Foam to the engine oil, and will do the same to the fresh fuel when the time comes.
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[modok]

good job! that should end your problems, just gotta loosen up those valve stems and you should be back in business

[cdennisg]

Any tips on how else I could get that valve unstuck? I soaked the stem as best I can with my witch's brew penetrant, and did the prying thing. the valve isn't hitting the piston top. Should I try to fire it off and see if it will unstick through vibration, compression (none) and a little heat?
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[modok]

THat's about all you can do without taking it apart, heat would help a lot but I cannot recommend using a torch near a valve spring.

Hopefully the lube you were able to get in there will soften it up by the time it's time to start it.

[cdennisg]

Thanks, I will probably try that. Next problem, I just shone a flashlight down the #1 intake pushrod, and it is definitely bent. I guess that means that #1 intake valve is stuck closed. I will try to get some penetrant in there, and pull the rocker arms off and maybe do some tapping on that valve stem to try to loosen the valve. It looks like the pushrod tube is bent, too, so I may be using one of my spring loaded tubes from my emergency spare parts box. I wonder if I will be disassembling the top end of this engine to make sure I can rely on it not having valves stick and bending pushrods?
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[cdennisg]

Last night, I dug deeper. See that #1 intake pushrod? It's sitting higher than the rest.

Here's why. I had to grab it with a pliers to pull it out, as it was bound in with the tube.

Threaded replacement tube installed. I will likely pull the heads off in the near future as several of the tube seals are leaking. I will replace this one with a stock tube at that time.

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[cdennisg]

So, #1 lifter was not stuck, it was the valve that was stuck closed and bent the pushrod. #3 intake valve was stuck open. I would assume the fact that these valves share a cam lobe was just a coincidence.

In an attempt to free the stuck valves for another test run, I tapped on the #1 valve with a soft hammer and was able to open it fully, but it stuck in that position. I used a heat gun, concentrated on the area next to the valve and in between the intake valves. After a couple of minutes, the stuck valve crept closed. I tapped it in again, and heated it again until it closed. I did this several times until it no longer stayed open on its own. I moved to #3 intake and did the same thing. Both valves now move freely, and do not stick open or closed. All other valves passed the tap-it-with-a-hammer-to-open-it trick. None of them stuck open.

Now the big question. If I try to run this engine, what is the likelihood that another valve or two will stick and bend another pushrod? I cleaned the tank, flushed the lines and pump, drained the carb and added fresh fuel with SeaFoam. I will be tearing this engine down eventually, at least to the point of replacing the pushrod tube seals and making sure there are no mouse nests or other hidden gems. Should I just wait until then, disassemble the heads and give them a good cleaning, or risk more damage by running it as is? For now, I just want the engine to run enough to move the bus around my property, not drive down the highway. I get tired of pushing them around the yard, and so does my wife.
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[skills@eurocarsplus]

true story:

a shop i worked at was famous for having people/customers stop by and give the owner crazy shit for free. low and behold, a customer gave my boss a 68 international loadstar 1600 single axle dump.

it 'ran when parked' 8 years prior when the customer bought the truck as a site truck when building his house. my boss, who would squeeze a dime out of a penny, decided to get it running.

long story short, it too had stuck valves. we just ran it at about 1800 rpm's and poured transmission fluid thru it's gullet. when the smoke cleared. it was running smooth as silk. i about shit in my hat. i couldn't believe it worked.

when were were slow, i had the joy of slapping on a dealer plate and hauling gravel for his new pool. i put about 3K on it before he sold it to a local farmer
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[cdennisg]

Are you stalking me now?

So whaddya think? Should I fire it up and see what happens? Or should I wait and pull the top end apart to make sure all is well?
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[modok]

fire it up!

Might be good to feed the carb some lube right before you shut it down again, couldn't hurt

[cdennisg]

I have some ATF, maybe I'll try that. I like making clouds of smoke. I spent many years winterizing boats, and storage fogging oil poured into a V8 carb did the trick!
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