The Stovebolt Site Forums The Shop Area Engine Shop 235 valve to rocker arm gap

So I put the head on & tightened it down, but my gap looks huge from the top of the valve stem to the rockerarm on #2 and #5(exhaust). It looks to be about 1 inch away. The pushrods are in the lifters, I can feel the lifter suck up as I pull the pushrod up. I'm hoping somebody can tell me if I'm just paranoid or do I have an issue. The bellhousing pointer is at the bb in the flywheel, and #1 & #6 are at tdc. I've never touched the cam gears/timing, just pulled the head. I'm afraid (big girl) to rotate the crank.
Any help guys?????

in most contexts, an inch isn't a lot, but in this case it is a whole lot. You should have about .006" for the intake and about .015" for the exhaust. (I am not sure these are the real correct numbers, but an inch is WAY too much) How do you know the pushrod is in the lifter? Have you actually laid eyes on it? (doesn't sound like it.) So do you have stuck valves? Why did you pull the head? If all you truly did was pull the head, you have a problem. However if you messed with the rocker arm adjusting screws/nuts, all you need to do is adjust them. But yes you have a problem. Don't even try to run it that way.

Are all the valve springs approximately the same height? It sounds like you've got a couple of stuck valves in the open position. Try measuring from the top of the spring retainer to the top of the head where the valve spring touches. Even partially-open valves should have a spring height within 1/2" or so of each other. Try backing all the adjusters off 5 or 6 turns each and measuring spring heights. They should be virtually the same for all valves if they're seating properly. Last resort, pull the side cover behind the distributor and visually confirm that all the pushrods are seated in the lifters properly. If a lifter or two has been sucked out of its bore during disassembly you would have a major difference in the position of those pushrods.
Jerry

Truck was parked outside for 7 Colorado winters before I bought it. I checked the compression and got 27-40 lbs across the 6. Pulled the head and it looked like every valve that was open or partially open had rusty seats/valves. No I have not removed the side cover (good point), I'm doing that right now. The head was just rebuilt with new valves guides and seats. I had not touched the adjusting nuts on the rockers, just removed the rocker shaft assembly and took it to the head shop. Thanks for your input.....back to that side cover now. I'll check back here in 10 mins.

"So I put the head on & tightened it down, but my gap looks huge from the top of the valve stem to the rockerarm on #2 and #5(exhaust). It looks to be about 1 inch away."

Is your rocker arm assembly in-place and torqued down (25-30 ft-lbs)?

I pulled the side cover over the pushrods. Who knew gm thought a 2 piece lifter was a good idea? The little cap had come off the top of the lifter and the pushrod had dropped into the lifter. Some lifters appear to have a wire clip holding the cap on top, not all but some. Problem found, thanks guys.

Be sure to secure the lifter tops with those snap rings before you reassemble things. I have seen "Tru-Arc" snap rings substituted for the wire clips by some people, but finding rings thin enough to fit the grooves in the lifter body can be a bit of a challenge. Carefully grinding the snap rings to a knife edge usually works if they're too thick.
Jerry

Adding into this thread for a similar problem with a 1960 vintage 261. Initially cylinders 5 & 6 intake values were stuck (hadn't been run by previous owner for years). Pulled the head, redid the values and guides. After reassembly I set all gaps cold and everything looked fine.

Having started the engine and allowed to get to operating temperature in order to do the final valve adjustment, I noticed some odd "mild clanking" (best I can describe the sound. Pulled the valve cover and cylinders 5 & 6, both intake and exhaust have rather large gaps, even after running the adjustment screws out almost all the way (see picture). Cylinders 1-4 seem OK. I've checked the rocker arms to cracks, etc... look good. Unless the machine shop actually did nothing and charged me anyway.... seems unlikely to be stuck valves still and they seem to be similar height to the other valves (will measure precisely later today).

Question is... any other thoughts of what might be going on. Before buttoning up the side plate I double checked that all the rods were properly seated when doing the cold gap adjustment. The only other thing I can think of is the camshaft lobes are worn down... but that seems a stretch.

Ideas and suggestions welcome... Thanks guys and gals

Unless the base circle of the cam lobes in question were also worn way down you wouldn't have that kind of gap on both valves in #6 at the same time. I think the valves and guides warmed up towards operating temperature and the valves stuck in the guides.

Marko2727 While you have your side cover off look at your cam lobes and lifters if lifters are convex on bottom and lobes are not rounded check to see if they all lift the same amount also don't mix them up. Put back on the same lobe,convex on the lifter can be checked with a straightedge it wont be much. If they rotate while running that is good. Good Luck !!

If they are stuck down at all, their heights would not match the heights of the normal ones. Take a rough measurement from valve top retainer to bottom of the head, where the spring sets.

So dumb question. How much oil is spewed if I was to run the engine for say 5 minutes with the valve cover off. The rockers arms weep, so think that would be OK and I could see better what's going on perhaps. What about removing the side panel so I can watch the lifters... seems like that one would get messy quick. Anyone tried either of these ?

Engine has been cleaned up fairly nice, chrome, etc.... so don't want to make a mess

So had a thought/question. Is it possible to put the rocker arm bar in backwards, and if so, is there a height offset that would cause the last 4 valves to perhaps be separated more than normal ? I'm thinking its odd my original problem was only cylinder 5 & 6 INTAKE, but not is both INTAKE and EXHAUST.

When I disassembled originally I wasn't expecting the spring-loaded pop-apart so things got a little off... but 95% sure I got everything back the way it came off. I've triple checked that the right numbered rocker arm is in the right position (of the 4 numbered types)... so that's not the issue I don't think. But is it even possible to put back together with the rear half bar on the front and the front on the back ? I know the middle oil feeder piece is right (can't remember what its call but has the pinched copper tube connecting to the head).

Just trying to think of what else I might be looking for why the gap is there.

Thanks all for the insights and suggestions... this is a great group.

Hey Joe. Maybe this will help.

You can run (at idle) the engine with valve cover off. It will sling a little oil. If you speed up the engine, it will make a mess. Cover your fenders. It will get some oil on your carburetor and manifolds. How do I know? On a seriously used Stovebolt, the rocker arm face may have an indention from wear. Almost impossible to get a good feeler gauge setting with either hot or cold engine. You can call it "shade tree" or "farm boy" but you can ** carefully ** adjust the valves with engine running at dead slow idle. It will leave marks in up your feeler gauge but on an old farm truck, you just want the truck to run. The proper solution is to pull the rockers and have them resurfaced at the machine shop.

If you look at the Master Parts List, the shaft part number is listed. Quantity is 2. So both halves of the RA assembly are the same.

RA orientation:
http://chevy.oldcarmanualproject.com/shop/1954truck/54ctsm0611.html
http://chevy.oldcarmanualproject.com/shop/1954truck/54ctsm0612.html

Thanks Bouymaker... so both ends of the rod are the same, unlikely that's it then.

Also, thanks for the picture. Reason for showing the picture was to show how much gap there is with so little screw left (just can see in the picture). So screw adjustment won't correct. I've though about getting a longer screw, but since its not designed that way that seems totally the wrong approach.... need to find the root cause and correct that; otherwise likely will make things worse and crack something.

thanks... joe

Joe, the bolt(s) that secures the rocker supports (there are 6 of them in the attached picture) is/are loose judging by your picture.
This is why your adjusters don't work.
All 6 bolts need to be torqued to 20/30 ft-lbs.
The supports hold the shafts that the rocker arms pivot on.
If the supports are not tight, valve adjustment is an act of futility.
I hope that makes sense.

I would start at the beginning and take out your push rods and make sure that they are all the same size. If they are, measure them for length. Let’s see what you are working with here.

I agree with buoymaker, after taking a closer look at your picture, the rocker arm was not installed properly. When you reinstall the rocker assembly, you must tighten it down evenly, a little at a time making sure that the pushrods stay in place and the assembly stays even. Once the assembly is seated (make sure all of the supports are touching the head), then torque the bolts to 20-30 ft. Lbs.

Also I also agree with Dragsix that you need you to measure the pushrods and additionally inspect them for any bent ones.

Before you tighten those bolts check with a 235 expert and see if there are supposed to be lock washers on them. I'm a GMC guy and the GMC sixes use lock washers in this place, but they are a completely different design. I don't have Chevy parts manuals that show this area.

No locks on chevy 235’s.

Buoymaker nailed it! Your own photo shows that the rocker pivot shaft standoff is not bolted down to the cylinder head all the way. No wonder there's an excessive gap. Maybe the bolt is cross threaded, or there might be some other reason for the big gap betweeen the stand and the head. Fix that, and the problem will go away.
Jerry

Great catch Hotrod Lincoln and Bouymaker. Indeed 3 of the 6 bolts were not snugged up. I even looked for this initially and somehow couldn't see it, even with it being the logical choice with all of the last 4 being too far separated.

In any case, related to all the other post comments, all the push rods are identical length, most are even new, double checked none were bent. Spring lengths in relaxed/uncompressed state were as follows, in case that helps someone else in the future

Intake Valves (#2,3,6,7,10,11): 1.81" to 1.84"
Exhaust Valves (#1,4,5,8,9,12): 2.02" to 2.06"

All buttoned up and now ready to roll, did first "short" road trip and everything seems great. Wish I could give you guys a PayPal donation or something for all the help.

Thanks... Joe

Joe, you can donate. Go to the Home page and you can find instructions there.

Joe you are one of the few that has provided a follow-up and a thank you after being helped.
That's simply cool! Thanks.

Thanks... that was kinda buried. WebMaster might want to consider putting a donate button front and center on the Home page :-)

I tried the PayPal link, but it doesn't work. I opened PayPal but not sure what email to use so it gets to the Stovebolt group. Also, I see a listing of folks that have donated over the years, but no amounts are listed... that's fine but doesn't give me an idea of what a typical donation is. Obviously a $10,000 would be greatly appreciated... but don't have that just lying around, but don't want to insult with say $100 either. Any guidance on how to make the PayPal donation and a typical amount or range ???

The e-mail for donations is [email protected]. Peggy and the gang will be grateful for whatever you send. I'm sure they wouldn't be insulted by a $100 donation, or even smaller if that's what you'd like to send.

As Kevin said, any donation large or small is greatly appreciated. There is also a snail mail address listed if you choose to go that route. The site owners don’t make a big plea for donations unless equipment needs replacing. Our needs are meager.