Probably about time-rocker adjustment

[pishta]

Well I took the drivers side rockers off and it looks like I have solid lifters. I only removed 3 pushrods and one of them is bent. Oh boy. I got a knot in my stomach now. Can I just order correct length pushrods, and adjust the valves and be done?View attachment 1715746158

Solids usually dont have a oil hole in the plunger seat......oil puddle, hole or illusion? The clip can be hard to spot if its a circlip and not a wire. Solids will have a different ramp rate than a hydro if you got a dial indicator. Measure it off the edge ideally. Hydro ramps are very short, they start moving right off the bat. Solids have a gradual run up ramp (in the thous) for a few degrees then a fast lift. Without a degree wheel and a dial indicator, your gonna be in the dark on what cam you have and its designed lash/ Make it an afternoon and pull the rad and timing cover: replace the chain (cheap enough while your in ther) , pull the cam and get the part number off the trans end. Just keep your lifters in order.

 

[Krooser]

Buy ONE pushrod.... Smith Bros, Manton and others will sell one.

 

[gtgto]

Buy ONE pushrod.... Smith Bros, Manton and others will sell one.

I was trying to find what I would need online after measuring and I look to have pushrods from a 273 4 barrel application along with the adjustable rockers from the same. I even got a melling part number. I was thinking about replacing them all since I have it apart. I was also thinking about a cam lifters and rocker shafts for the original hydraulic setup that would've come in my car originally. I don't want to rush my decision just on the fact I would rather be driving it than having it laid up in my garage.

 

[4spdragtop]

Up to you but the adjustable setup is more versatile and worth $$

 

[ocdart]

I'm late to the party here but suggest you keep your adjustable rocker setup even if you decide to return to a hydraulic cam and lifters.
The 273 adjustable rocker system is a good setup for a street engine with either a hydraulic or solid lifter cam.
If you return to a hydraulic cam and lifters, you shouldn't have to adjust your valves often but you can always check them for proper hydraulic lifter preload.
If you decide to remain with a solid cam and lifters you will need to adjust the valve lash periodically.
You can only correctly check valve lash on both intake and exhaust valves of one cylinder at a time. Both intake and exhaust valves have to be fully closed with their respective lifters on the base circle of the cam.
After setting the valve lash of both valves of a specific cylinder you will move on to the next cylinder and rotate the engine so again, both valves are fully closed with their respective lifters on the base circle of the cam. There is a specific method in doing this so find the procedure and follow it to the letter.

 

[gtgto]

I'm late to the party here but suggest you keep your adjustable rocker setup even if you decide to return to a hydraulic cam and lifters.
The 273 adjustable rocker system is a good setup for a street engine with either a hydraulic or solid lifter cam.
If you return to a hydraulic cam and lifters, you shouldn't have to adjust your valves often but you can always check them for proper hydraulic lifter preload.
If you decide to remain with a solid cam and lifters you will need to adjust the valve lash periodically.
You can only correctly check valve lash on both intake and exhaust valves of one cylinder at a time. Both intake and exhaust valves have to be fully closed with their respective lifters on the base circle of the cam.
After setting the valve lash of both valves of a specific cylinder you will move on to the next cylinder and rotate the engine so again, both valves are fully closed with their respective lifters on the base circle of the cam. There is a specific method in doing this so find the procedure and follow it to the letter.

So consensus is to keep what I have as far as adjustable rockers and shafts. Sounds like a plan. Hoping to do pushrods. and re install rockers and measure what the valve lash was set for originally.. If the measurements are consistent I will go with that. If they are all over the place the cam will have to come out to get make and part number to lookup recommended lash adjustment. Valves closed meaning no spring compression at all on both intake and exhaust valves on same cylinder right? Just making sure.

 

[gtgto]

So I got my new pushrods today. Melling MPR-155. Put one of the new ones next to the old one and they are a little longer, like a 1/4 inch.. I'm pretty sure they will still work since the adjustable rockers look to have more than that pushing out of the rocker. Since I was going to reassemble with the old pushrods and measure the lash that was set and duplicate it with the new pushrods. Not exact by any means. Or should I do things correctly and remove my intake and timing cover to inspect everything and remove the cam to get a part number to get the correct valve lash and then reassemble? I think I know the answer in my head but what do you all recommend?

 

[RustyRatRod]

So I got my new pushrods today. Melling MPR-155. Put one of the new ones next to the old one and they are a little longer, like a 1/4 inch.. I'm pretty sure they will still work since the adjustable rockers look to have more than that pushing out of the rocker. Since I was going to reassemble with the old pushrods and measure the lash that was set and duplicate it with the new pushrods. Not exact by any means. Or should I do things correctly and remove my intake and timing cover to inspect everything and remove the cam to get a part number to get the correct valve lash and then reassemble? I think I know the answer in my head but what do you all recommend?

Hopefully you kept up with which hole each lifter came out of. That's important. Also, there ARE solid lifters with both the oiling hole in the top AND the clip holding a solid plunger. So be careful there, too.

 

[rustycowll69]

how many threads of the adjusting screws were protruding from the bottom of the rockers right now?

 

[gtgto]

Hopefully you kept up with which hole each lifter came out of. That's important. Also, there ARE solid lifters with both the oiling hole in the top AND the clip holding a solid plunger. So be careful there, too.

I haven't removed the lifters yet but will keep them in order when I remove them, I'm not understanding your second part of your reply.

 

[gtgto]

how many threads of the adjusting screws were protruding from the bottom of the rockers right now?

I took a look and there aren't really any threads protruding from the bottom of the rocker. I seated the cup on the ball and I have about a 1/4 of an inch between the bottom of the rocker and the top of the pushrod. Since I have a few threads out of the top of the rocker I'm now thinking I should go a little shorter then the 7 and 5/16 I already have or an 1/8th longer at most.

 

[pishta]

.250 over is pretty big.
"...adjustable rockers and solid lifters = 7.34", adjustable rockers and hydraulic lifters = 7.25", non adjustable rockers and hydraulic lifters = 7.51"

273 stock push rod length?

 

[rustycowll69]

.250 over is pretty big.
"...adjustable rockers and solid lifters = 7.34", adjustable rockers and hydraulic lifters = 7.25", non adjustable rockers and hydraulic lifters = 7.51"

273 stock push rod length?

I agree 1/4" longer is a lot, especially since you say there were no threads protruding with the original adjusting screws and old pushrods. If you have access to a small lathe and the cup ends on the new pushrods are not spot-welded to the tubing, you can chuck them up in the lathe and use a parting tool to shorten the pushrod tubing. It's really quite easy. The cup end has a like a 3/8" long stem shoved into the tube. You run your parting tool slowly into the tube up next to the cup shoulder until you hit the stem. It won't cut into the stem because the cup is hardened. Then you just tap the cup end further into the tube until the shoulder runs up against the new cut end of the pushrod tube. Rinse, repeat as necessary until you get the proper length.

 

[pishta]

..If you have access to a small lathe and the cup ends on the new pushrods are not spot-welded to the tubing, you can chuck them up in the lathe and use a parting tool to shorten the pushrod tubing. It's really quite easy. The cup end has a like a 3/8" long stem shoved into the tube. You run your parting tool slowly into the tube up next to the cup shoulder until you hit the stem. It won't cut into the stem because the cup is hardened. Then you just tap the cup end further into the tube until the shoulder runs up against the new cut end of the pushrod tube. Rinse, repeat as necessary until you get the proper length.

Bingo

 

[RustyRatRod]

I haven't removed the lifters yet but will keep them in order when I remove them, I'm not understanding your second part of your reply.

The other guys were basically saying if your lifters have a retaining clip in the top, they were hydraulic. That's not necessarily true. There are also solid lifters that have a retaining clip as well and are almost indistinguishable from a hydraulic lifter upon visual inspection. So make sure you keep us posted with what you find.

 

[RustyRatRod]

I took a look and there aren't really any threads protruding from the bottom of the rocker. I seated the cup on the ball and I have about a 1/4 of an inch between the bottom of the rocker and the top of the pushrod. Since I have a few threads out of the top of the rocker I'm now thinking I should go a little shorter then the 7 and 5/16 I already have or an 1/8th longer at most.

Pictures would be best here before you start replacing things.

 

[yellow rose]

The other guys were basically saying if your lifters have a retaining clip in the top, they were hydraulic. That's not necessarily true. There are also solid lifters that have a retaining clip as well and are almost indistinguishable from a hydraulic lifter upon visual inspection. So make sure you keep us posted with what you find.

Yep. My lifters are solids and they have a retaining clip that makes it look like a hydraulic lifter.

 

[RustyRatRod]

Yep. My lifters are solids and they have a retaining clip that makes it look like a hydraulic lifter.

Yup those are nice. Oil metering solids. Chevy used um forever.

 

[gtgto]

The other guys were basically saying if your lifters have a retaining clip in the top, they were hydraulic. That's not necessarily true. There are also solid lifters that have a retaining clip as well and are almost indistinguishable from a hydraulic lifter upon visual inspection. So make sure you keep us posted with what you find.

Post 17 has pic of top of lifters. I might remove my intake tomorrow to get a better look at things.. That or with a magnet try to get a lifter out. I am pretty sure they are solid. They do not compress at all when I tried to push down on the pushrod. I did not go crazy and push down very hard though. What started this all is the engine seemed to be noisy at around 3000 rpm's and seemed to be down on power. After removing rockers and pushrods I found one PR was bent. Since I do not know the cam specs I do not know what the proper valve lash is supposed to be.

 

[RustyRatRod]

Post 17 has pic of top of lifters. I might remove my intake tomorrow to get a better look at things.. That or with a magnet try to get a lifter out. I am pretty sure they are solid. They do not compress at all when I tried to push down on the pushrod. I did not go crazy and push down very hard though. What started this all is the engine seemed to be noisy at around 3000 rpm's and seemed to be down on power. After removing rockers and pushrods I found one PR was bent. Since I do not know the cam specs I do not know what the proper valve lash is supposed to be.

I saw it, but it's impossible to tell. Remove ONE if you can. Put it on a flat surface and put a pushrod into the cup and see if you can press down on the plunger (if it has one) and bleed the oil out. Then, if the plunger is spring loaded, and returns back to the top after you push it down, it's hydraulic. If you can shake the lifter and it rattles from the plunger rattling freely, it's solid......and nice solid lifters, too. Oil metering like I described above. They may just be a solid hunk of metal, which is fine too.

 

[gtgto]

I saw it, but it's impossible to tell. Remove ONE if you can. Put it on a flat surface and put a pushrod into the cup and see if you can press down on the plunger (if it has one) and bleed the oil out. Then, if the plunger is spring loaded, and returns back to the top after you push it down, it's hydraulic. If you can shake the lifter and it rattles from the plunger rattling freely, it's solid......and nice solid lifters, too. Oil metering like I described above. They may just be a solid hunk of metal, which is fine too.

I got a lifter out. I tried to push down on it but it

I saw it, but it's impossible to tell. Remove ONE if you can. Put it on a flat surface and put a pushrod into the cup and see if you can press down on the plunger (if it has one) and bleed the oil out. Then, if the plunger is spring loaded, and returns back to the top after you push it down, it's hydraulic. If you can shake the lifter and it rattles from the plunger rattling freely, it's solid......and nice solid lifters, too. Oil metering like I described above. They may just be a solid hunk of metal, which is fine too.

Got a lifter out and tried to push on the plunger with a pushrod and it didn't move. I shook it and feel a rattle and oil is splattering out of it. Here are pics.

 

[flyfish]

Before installing the new prod, I would be finding out why the original one bent...

^^^^^This....

 

[rustycowll69]

^^^^^This....

I agree. That's why I asked about the shaft orientation. When dealership screwed up my rocker shafts, the second symptom was bending a pushrod. The first symptom was an intermittent miss. The final symptom was stalling. That's when I started exploratory surgery and found that the rockers were welding themselves to the shafts from lack of lubrication. That was 45yrs ago.

 

[RustyRatRod]

I got a lifter out. I tried to push down on it but it

Got a lifter out and tried to push on the plunger with a pushrod and it didn't move. I shook it and feel a rattle and oil is splattering out of it. Here are pics. View attachment 1715751104View attachment 1715751105View attachment 1715751106

The your question has been answered. If you're hearing a rattle when you shake it, that's the oil metering plunger. You have oil metering solid lifters. A hydraulic lifter will not rattle, since it has a preload spring and different internals. Nice diagnostic work!

 

[gtgto]

My original plan has taken a different direction for sure. Was able to get the cam out tonight after removing and keeping the lifters in order. Found one lifter that was shot along with the cam lobe it lined up with. Now I'm apparently doing cam and lifters and a new chain while I'm at it. Car is a stick with 3.91's and manual brakes. Engine was cast in early 1970. Heads are U heads with what look like stock valve springs with the center coil dampener present. I would like to replace the cam and lifters and have a little bit of a choppy idle. Nothing drastic that I would need to replace valve springs. Whats the cam of choice? I always hear about the stock 1968 340 4 speed cam. Are they reproduced today? Any help would be greatly appreciated. Thanks