The Stovebolt Site Forums The Shop Area Engine Shop Some 235 Valve sticking weirdness - help!

Brand new here, hello!

My daily driver is a 1960 Chevrolet Thriftmaster 3/4 Ton Step Van.

Factory 235 with the Carter Ball & Ball updraft carb....has 106,000 original Miles.

Out of no where, the other day, it was hard to start, and, turns out, the Valves are all sticking and not following back "up" to stay close to the Tappets.

What the heck is going on?

I went through things when I got it, and, I have had it in daily use for three years with no issues of any sort, always ran like a Champ, starts buh-da-bing!.


With Valve Cover off, and, cranking it over, you can see the Valves sticking in their wide open position, snapping back with delay or creeping back slowly, merely, to where even some of the Push Rods left their upper socket in the Tappet.


Is this maybe from not using a Lead Additive maybe in the Pump Gas I run? ( like I probably should have been doing? )


Or..?


Phil
Las Vegas

Hey guy,
Not to worry, This dose happin. I have had the same issue my self. The issue is your valve springs are worn out. I simply installed new valve springs and valve seals. The valve springs were $1.70 each at rockauto.com and I added .030 shims as well. I have the 3.90 gears and it will run 65. So it will help your rpm rang as well. You can put the cylinder your replacing the springs on at TDC and the valve will not fall out. Any other questions let me know.

Hi GrandpasTruck,


Okay...well, new Valve Springs would certainly not hurt anyway, I'm sure.

May as well do it!


The old Van is such a sweetie, and a joy to drive.

Sweet spot for sustained cruising is about 47 MPH, 50 maybe.

4-11s, all Steel, 5100 lbs Curb Weight if memory serve. Three on the Tree.

I am a Carpenter and it is my 'Baby' for Work related forays, and even then, I seem to only put on about 2,500 Miles a Year, so, never a strain on the old thing.

I always ran 'MARVEL' Mystery Oil in everything, somehow, last few years, I just plum forgot to be doing it...I will get back onto that now, after this, even if it is a Spring issue and not a Valve Stem being somehow sticky as the issue.

Thanks!


Phil
Las Vegas

As always results may very. Make sure you check the free travel of the valve once you remove the valve spring and to run a zinc additive like ZDDP. Oil no longer has a lot of zinc in it due to the EPA. Here is the link to my truck page. Pics at the bottom of my new springs and old. Rockauto.com is the cheapest you will find anywere on springs and seals.


http://www.cardomain.com/ride/3364051/1959-chevrolet-apache/page-3

Good luck keep me up to date on it.

Hi GrandpasTruck,


I really enjoyed looking through the Album you have for your 1959 Apache. Good looking Truck!

I relate to the many small things and large things one usually has to do to have a 'Been Sitting' be a snug, reliable Daily Driver. Always the neglect and oddities of former owners to get through and make right.


Here's some snap shots of my 1960 'Thriftmaster' Step Van -


http://public.fotki.com/PhilBphil/1960-chevrolet-thri/


As you can see, I have made a few, small 'period-correct-enough' and I hope tasteful changes to a few things, still have some Front Turn Signals to fit in ( as it happens, 1946 Ford Car Parking Lights fit the curve of the front area perfectly, and look REALLYT good there, so, those will be my front Turn Signals ), and the 'new' Front Bumper to make mounts for and get it installed, and, well, a little here and a little there.


I did not know about the Zink thing, I will look into getting an additive.

Additional ZDDP is not required, just a bunch of snake oil by the sellers of the additive. The only time it really becomes an issue is if you're running extremely high valve spring pressures, something you really won't run into with a street driven engine, and definetly not on a stock 235.
Just from the description you give, while I wouldn't rule out weak springs, sounds more like sticking valve guides. They're probably varnished up. If you're going to do the springs, I would advise removing the head and taking to the local machine shop. That way, they can check the valves and guides for any issue, plus boil the head in the hot tank to clean it out.

Hi Bill,


The way this happened literally overnight...started and ran fine one day same as ever, next morning, acting weird, but, still started and ran fine but backfired and was hard to start initially when cold...once warmed up, would restart fine and instantly..next morning, would not start at all, backfiring, lots of Valve Tappet Noise...then I pulled the Valve Cover to look, found I had bent a Push-Rod ( which I later realized, had bent for how when the Valve did not come up fast enough to follow close onto the Tappet, the Push Rod upper end was off to the side, under the Tappet too close to the Rocker Arm...and when the Lifter came up, the Push rod was trapped...)


I wonder if I got a batch of Bad Gasolene which made all my Valve Stems Varnish up so fast..?

Turning it over, and, watching with the Valve Cover off, was surreal - I did not see any of the Valves coming up fast, they either paused and jerked up part way then crept the rest of the way slowly, or, went up slowly the whole way.


Darn, and I am right in the middle of a Job presently! - where, I need the Van to get Lumber and so on, Lol...


Might be best for me to pull the Rocker Arm [censored]'y anyway...see if I can soak the available parts of the Valve Stems in 'KROIL' or something, try whatever I can to free them up harmlessly, Heat even, and, install new Valve Springs while I am at it.


Pulling the Head off, I could do, for sure, bring it to a Shop which does Heads, and, have them go through it to free things up and install new Springs even, or, doo all that vhere on a Banch, but, if I can get this situation rectified without doing that, I'd be a happier Boy.


I am thinking I ought to dump in a good Pint of Marvel, and, ditto of Acetone or Deisel or both, or all three I mean, to help whatever may have been going on with that last Tankfull of Gas...or, just drain off the Gas that's in it, and use it for cleaning things now and then I guess. And put in new Gas.

wow. That is the first 235 updraft I have seen. Looking sharp. You have a nice project on your hands. Good luck.

P.S. Zinc is a must for anything with solid lifters.

Well, tomorrow I will go to PepBoys and get some "ZDDP"....drain and flush the Pan, and add new Oil and add the ZDDP also.


I went on-line to Rockauto.com, and, have my New Valve Springs on the way, and, a set of new Seals also.

Woo Hoo!


I drive slow, and lucky me, all my Carpentry Work the last several years, has all been within half a Mile from my Shop, so, even though I drive most every day, it is never far, or over 35 or 40 MPH on the Secondary Streets, so, I did not get the Shims...

Thank you!


I had always wanted a Step Van for Work, and, getting this Chevrolet Model has been a joy in every way...I put about 150 solid Hours into it so far, fixing things, re-doing things, improving little things, while keeping it on the Road pretty well constantly, but for the delay when doing the Major Brake Job ritual ( and the present lay up). Rewired 90 percent of it.

You sit up high, my Seat is about the same level as everyone else's roof top, so, great view, plenty of dignity, no one expects me to go fast, and, I do not disappoint them. Easy to find in any Parking Lot when I come out of a store.

I just keep the driver's door open all the time, sometimes both front doors, open and latched, gives you a nice Breeze, plus I can see and hear better for outside sounds and so on.

I have been very happy with it.

Everything is 'Clutch Head' screws on it...

Steering is snug and positive, Steers with one finger once at a walking speed or so. Brakes now are really good, just touch the Key and it fires up ( well, it DID till this Valve thing happened ).

Gets lots of compliments every where I go...people always wanting to buy it and have it for their Business.

It's my Baby though, and, I plan to keep it and have fun with it for the long haul.


Once again, Chevrolet pulls out ahead!

IMHO the head has to come off.
The clearance between the intake valve and piston @ TDC is less than your lift, which means if the valves really stayed full open all 6 intakes hit the pistons. The exhausts have plenty of room, and won't make contact.
Most likely you'll just have marks on the domes, since the cranking speed is low and the valves are nearly vertical.
If you're not lucky the stems are bent.

Hi panic,


Ohhhhhhhh, okay, makes sense.


As far as I have seen, all Valves have full range of motion, but, they are slow and or pausing then jerking to catch up to close the gap between the Tappet and the end of their Stem...so, hopefully, none are Bent from being hit by the Piston Top...but, this was not a deliberate observation, just that I do not remember anyonbe stayiing 'open' for more than a few seconds once I stopped Cranking ( and, I was only cranking in very short amounts anyway).


Yeahhh...probably be best to pull the Head, and, really make sure all have free travel, none are bent, inspect the Valve Seats for erosion or whatever, and, install the new Springs and Seals that way.

New Head Gasket, too of course...at that point.


Darn...I am so swamped with other obliges right now, I might just pull the Head and drop it off to a place I know of which rebuilds Engines and Heads and so on, and, have them do it.

I'd rather do it myself, but, days are too full already.


Thanks!


Phil
Las Vegas

on mine I pulled the valve cover and cranked it over by hand. I could see the vlave being pushed back up by the piston. So you can try that if you want. Makes sence to have a head shop do it. But I am cheap and just put on springs. Has not failed me yet. But I will rebuild the head some day down the road.

I don't know how you can tell the valves are not bent unless you have them out already. I would wait with the valve springs until I find out what the real problem is. If you bent a push rod, it is possible and likely you bent a valve too. No sense replacing parts until you test them. If you are having a valve job, many places will replace the valves anyway.

Well, been squirting "KROIL" onto the avaailable Valve Stems, and, turning the Engine over a few times, and repeating.

So far many of the Valves are still slow to return., neding a second or more to catch up to the Rocker.

Where is a good source for obtaining a Head Gasket?

Just a Head Gasket I mean, by itself?

NAPA sells different styles/compositions of 235 head gaskets (by itself).

Well, hello again everyone!

I hope your Chevrolet Sixes have been doing well and running strong!


Mine ended up sitting for 3 years and 2 Months...just had so much else going on, Moved across Town, till finally two weeks ago, I got back on it.

Got the Head rebuilt, got a load of other things done on the old Van also.

Now working on resolving an Intake/exhaust Manifold problem - it is as if the Intake Manifold had shrank...is too low to match the Intake Ports on the Head...and, sits a little back from the plane of the Exhaust Manifold's flange fronts.

I will begin a Thread about that...maybe some of you all have encountered such a thing before.