I've been chasing a valve sound for quite a while now. I adjusted the valves to .006 and 018 according to some information I got. Valves were more noisy than ever. Adjusted them to 0.006 and 013 and things were a little better. I still had the sound but not as bad and I thought perhaps it was a timing/ignition issue. I realized that the vacuum advance was shot so I ordered a new one and installed it. Set the timing to 5° advance. I replaced the 6 volt coil , cap , rotor, and spark plug wires. I did a compression check into my surprise I had 130 lbs in each cylinder.
Now, the noise is only there when the engine has a slight load on it. No valve noise at idle and no valve noise with a lot of throttle. I retarded the timing to 3° advanced, that didn't help. I then set it to 10° advance and that didn't help either. So, it's back to 5° advance.
Does anyone have any ideas for what I should check next?
1946 1/2 ton Chevy Pickup 1954 235 cu in 3 speed on the floor
I'd get a vacuum gauge and connect it to your intake manifold, adjust the distributor to highest vacuum. Adjust the lifters when motor is up to temperature, also should be several good tech tips re. adjusting lifters on this forum.
Beautiful truck BTW, the blue and black is an eye catcher!
Last edited by JiMerit Boltr#43; 03/31/20233:43 PM.
Are you positive you have solid lifters? A friend with a '50 had a '55 engine that he thought had solid lifters. We adjusted them all over the place with little luck. Finally pulled one out and found that it was hydraulic. Used hydraulic adjustment procedure and now "All's quite on the Western Front".
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
Look at the tips of your rocker arms where they contact the valve stems. You'll probably find that they have divots worn in them that prevent you from getting an accurate lash setting. You could also find someone to degree the cam and figure out what the lash setting is supposed to be instead of guessing about it. Once you're sure the lash setting is correct, any rattle you hear will be something other than mechanical noises in the valve train. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Are you positive you have solid lifters? A friend with a '50 had a '55 engine that he thought had solid lifters. We adjusted them all over the place with little luck. Finally pulled one out and found that it was hydraulic. Used hydraulic adjustment procedure and now "All's quite on the Western Front".
I'm going to get the vacuum gauge out. I'm fairly certain these are solid lifters. When I first started this task, a couple months ago, all the intake valves were at.006 and a hydraulic lifter wouldn't have had any lash at all. I may double check by pulling the cover off the side of the engine. Thanks for the compliment on the truck. It was a standard color combination from what I understand. Postal blue and black
1946 1/2 ton Chevy Pickup 1954 235 cu in 3 speed on the floor
adjust the distributor to highest vacuum Since that's a "no load" condition, it's frequently too much when loaded.
W/r/t valve lash with solids. Regardless of what figure is used, the purpose is the same: that the valves always close completely no matter what the load, RPM or temperature is. Subtracting lash (in the hope of improving peak power by extending the duration) is only as safe as the limits I just gave. If the valve stays open, that cylinder stops working. Adding lash to reduce duration makes some difference, but also increases lobe/tappet wear (and noise) significantly.
Removing the side cover isn't necessary. If you get a valve fully closed with the engine stopped and put a constant steady pressure against the pushrod side of the rocker arm with a pry bar or a long screwdriver for a couple of minutes, a hydraulic lifter will collapse and the gap at the valve stem will increase- - - -up to maybe 1/8" or a bit less. It doesn't require much force, just a moderate amount of tension for a while. A solid lifter will not collapse, no matter how long the tension is applied. Once the engine is started, a collapsed hydraulic lifter will rattle for a few minutes while it pumps up again.
Setting ignition timing with a vacuum gauge is an utter waste of time and effort. It's sort of a "measure it with a micrometer- - - -mark it with chalk- - - -cut it with an ax" procedure. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Removing the side cover isn't necessary. If you get a valve fully closed with the engine stopped and put a constant steady pressure against the pushrod side of the rocker arm with a pry bar or a long screwdriver for a couple of minutes, a hydraulic lifter will collapse and the gap at the valve stem will increase- - - -up to maybe 1/8" or a bit less. It doesn't require much force, just a moderate amount of tension for a while. A solid lifter will not collapse, no matter how long the tension is applied. Once the engine is started, a collapsed hydraulic lifter will rattle for a few minutes while it pumps up again.
Setting ignition timing with a vacuum gauge is an utter waste of time and effort. It's sort of a "measure it with a micrometer- - - -mark it with chalk- - - -cut it with an ax" procedure. Jerry
I tried to vacuum gauge and couldn't get good results. I went back to the timing light. Thanks for the tip on checking for hydraulic. I ran out of time today but I'm going to try it in the morning.
1946 1/2 ton Chevy Pickup 1954 235 cu in 3 speed on the floor
The correct valve lash setting for a 54 235 with solids is 10 intake and 20 exhaust---hot. This info is in the 54 chev truck owners manual. I tried the 6/13 route and after finding the above info is what I set mine as. Sounds like a well oiled sewing machine. Hope this helps.
If it's a truck block,it's not drilled for hydraulic lifters until the late fifties and then maybe only 261s. Not sure. A high water pump 235 engine will have solids unless it came out of a Power-Glide car. If somebody put hydraulic lifters in a truck engine they will not pump up at all. If somebody put in a hydraulic cam with solid lifters, it will be very noisy.
I was in a jam once (1978) and hired someone else work on my truck, replacing a cam ruined when the fiber cam gear let go. They put in a hydraulic cam because that's what they had lying around. It was way noisy at solid lash spec. After I got tired of keeping the lash to 0.002 so I could hear myself think, I bought a set of hydraulic lifters to put in. That didn't work at all because the lifter gallery wasn't drilled for oil pressure. I ultimately had to install a solid lifter cam with all that entails (remove radiator, grille, timing cover etc.). That ran for about 20 years until I put a hotter cam in.
1951 3800 1-ton "Earning its keep from the get-go" In the DITY Gallery 1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.
Making wild-donkey guesses about cam profiles and lash settings is a monumental waste of time, given all the possible combinations of cams and lifters and other variable factors that can affect valve train noise. A degree wheel and a dial indicator can resolve the problem quickly and accurately, but only if someone is capable of understanding how they're used and what results to look for. The whole thing boils down to the thickness of a few strands of hair, and maybe 10 to 20 degrees of crankshaft rotation at the beginning and end of the transition of the base circle of the cam to the lift lobe. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I have laid my eyes on both solid lifter cams and hydraulic lifter cams from 235s, and I cannot discern any difference with my eyeballs. It is very easy for me to recognize a hydraulic cam from say, a 350 by looking at it. The profile of the lobes are substantially different, and stand out like a sore thumb. What's up with that?
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
The only solid lift cams for small block V8's that are being made any more have such a radical profile that they're easy to recognize. Hydraulic small block cams are capable of 7K RPM and .500" valve lift or more these days. That was unheard of a few years ago. The main reason is that there are valve springs available that can control valve float at extreme speeds and prevent valve float that was once the downfall of hydraulics. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
