Sudden lifter / Rocker noise - potential causes?
11-29-2015, 06:13 PM
#41
Race Director
Imothph,
I am going to throw some more at you..and it may help it may not.
Some STUPID QUESTIONS:
1.) The engine has a new harmonic balancer on it????
2.) The timing tab that is bolted to the timing chain cover. Is it the CORRECT one for the diameter of the balancer you are using...thus meaning that the timing tab gauge ALMOST can touch the balancer due to being so close to it...correct???
3.) These distributors your are using...are they new??? I am guessing that they are GM HEI's???
4.) If you answered YES to question #3. I assume the ignition coil is NEW??? IF you answered YES.....I have had this bite me in the backside...where the coil coming from some suppliers like to shoot black paint on them....and in doing so....the metal ground strap that goes UNDER the coil when you put it in the cap CAN NOT make good contact to the coil housing....SO...if your coil is painted black. I clean off the paint for the ground strap area and also where the ground wire gets secured to the coil when it is bolted in place also. JUST A THOUGHT.
5.) When you crank the engine when it is cold...do you have a FAST IDLE ??? Approx 1500 RPM's?? And when the engine is warming up...can you get it to come off of fast idle and get to curb idle???
Only because I mentioned it before...I would have to verify that the lifters are not stuck where the plunger is. YEAH...I know...if they were stuck partially down ..the rocker would clatter. So..I guess if you are getting no noise from your rockers...you can do it or not do it.
Have you by any chance performed a compression test??
I know that this is a real stretch....but I have seen camshafts that were ground wrong and when you spin the cam..you can actually see how the lobe separation is off.
I am at a loss of any more thoughts.....some of there are real 'stretches' of the imagination. Possibly the vacuum to your advance can be plugged off or go to ported vacuum instead of manifold vacuum...and see how it does when it is cranked up cold.
I assume you have tried to use Kv tester (Kilovolt)when checking your spark at the plug area??? Mine has saved me a lot of hunting and searching.
DUB
I am going to throw some more at you..and it may help it may not.
Some STUPID QUESTIONS:
1.) The engine has a new harmonic balancer on it????
2.) The timing tab that is bolted to the timing chain cover. Is it the CORRECT one for the diameter of the balancer you are using...thus meaning that the timing tab gauge ALMOST can touch the balancer due to being so close to it...correct???
3.) These distributors your are using...are they new??? I am guessing that they are GM HEI's???
4.) If you answered YES to question #3. I assume the ignition coil is NEW??? IF you answered YES.....I have had this bite me in the backside...where the coil coming from some suppliers like to shoot black paint on them....and in doing so....the metal ground strap that goes UNDER the coil when you put it in the cap CAN NOT make good contact to the coil housing....SO...if your coil is painted black. I clean off the paint for the ground strap area and also where the ground wire gets secured to the coil when it is bolted in place also. JUST A THOUGHT.
5.) When you crank the engine when it is cold...do you have a FAST IDLE ??? Approx 1500 RPM's?? And when the engine is warming up...can you get it to come off of fast idle and get to curb idle???
Only because I mentioned it before...I would have to verify that the lifters are not stuck where the plunger is. YEAH...I know...if they were stuck partially down ..the rocker would clatter. So..I guess if you are getting no noise from your rockers...you can do it or not do it.
Have you by any chance performed a compression test??
I know that this is a real stretch....but I have seen camshafts that were ground wrong and when you spin the cam..you can actually see how the lobe separation is off.
I am at a loss of any more thoughts.....some of there are real 'stretches' of the imagination. Possibly the vacuum to your advance can be plugged off or go to ported vacuum instead of manifold vacuum...and see how it does when it is cranked up cold.
I assume you have tried to use Kv tester (Kilovolt)when checking your spark at the plug area??? Mine has saved me a lot of hunting and searching.
DUB
11-30-2015, 03:55 PM
#42
Instructor
Thread Starter
Imothph,
I am going to throw some more at you..and it may help it may not.
Some STUPID QUESTIONS:
1.) The engine has a new harmonic balancer on it????
2.) The timing tab that is bolted to the timing chain cover. Is it the CORRECT one for the diameter of the balancer you are using...thus meaning that the timing tab gauge ALMOST can touch the balancer due to being so close to it...correct???
3.) These distributors your are using...are they new??? I am guessing that they are GM HEI's???
4.) If you answered YES to question #3. I assume the ignition coil is NEW??? IF you answered YES.....I have had this bite me in the backside...where the coil coming from some suppliers like to shoot black paint on them....and in doing so....the metal ground strap that goes UNDER the coil when you put it in the cap CAN NOT make good contact to the coil housing....SO...if your coil is painted black. I clean off the paint for the ground strap area and also where the ground wire gets secured to the coil when it is bolted in place also. JUST A THOUGHT.
5.) When you crank the engine when it is cold...do you have a FAST IDLE ??? Approx 1500 RPM's?? And when the engine is warming up...can you get it to come off of fast idle and get to curb idle???
Only because I mentioned it before...I would have to verify that the lifters are not stuck where the plunger is. YEAH...I know...if they were stuck partially down ..the rocker would clatter. So..I guess if you are getting no noise from your rockers...you can do it or not do it.
Have you by any chance performed a compression test??
I know that this is a real stretch....but I have seen camshafts that were ground wrong and when you spin the cam..you can actually see how the lobe separation is off.
I am at a loss of any more thoughts.....some of there are real 'stretches' of the imagination. Possibly the vacuum to your advance can be plugged off or go to ported vacuum instead of manifold vacuum...and see how it does when it is cranked up cold.
I assume you have tried to use Kv tester (Kilovolt)when checking your spark at the plug area??? Mine has saved me a lot of hunting and searching.
DUB
I am going to throw some more at you..and it may help it may not.
Some STUPID QUESTIONS:
1.) The engine has a new harmonic balancer on it????
2.) The timing tab that is bolted to the timing chain cover. Is it the CORRECT one for the diameter of the balancer you are using...thus meaning that the timing tab gauge ALMOST can touch the balancer due to being so close to it...correct???
3.) These distributors your are using...are they new??? I am guessing that they are GM HEI's???
4.) If you answered YES to question #3. I assume the ignition coil is NEW??? IF you answered YES.....I have had this bite me in the backside...where the coil coming from some suppliers like to shoot black paint on them....and in doing so....the metal ground strap that goes UNDER the coil when you put it in the cap CAN NOT make good contact to the coil housing....SO...if your coil is painted black. I clean off the paint for the ground strap area and also where the ground wire gets secured to the coil when it is bolted in place also. JUST A THOUGHT.
5.) When you crank the engine when it is cold...do you have a FAST IDLE ??? Approx 1500 RPM's?? And when the engine is warming up...can you get it to come off of fast idle and get to curb idle???
Only because I mentioned it before...I would have to verify that the lifters are not stuck where the plunger is. YEAH...I know...if they were stuck partially down ..the rocker would clatter. So..I guess if you are getting no noise from your rockers...you can do it or not do it.
Have you by any chance performed a compression test??
I know that this is a real stretch....but I have seen camshafts that were ground wrong and when you spin the cam..you can actually see how the lobe separation is off.
I am at a loss of any more thoughts.....some of there are real 'stretches' of the imagination. Possibly the vacuum to your advance can be plugged off or go to ported vacuum instead of manifold vacuum...and see how it does when it is cranked up cold.
I assume you have tried to use Kv tester (Kilovolt)when checking your spark at the plug area??? Mine has saved me a lot of hunting and searching.
DUB
On question #3, the distributors were a mix of brand new (two of them) and original GM out of the old engine. Believe it or not, my old HEI unit actually performed the best initially - the MSD streetfire was horrible, and the new Accel unit ended up being the best of them. I shimmed it to 0.018 and used a matching Pertronix module and coil - which came out of yet another new distributor that was otherwise mechanically damaged on arrival. The coil is new, I actually have three new coils and a functional old one - tried them all. Two are are performance-oriented - a Pertronix Flamethrower and a D.U.I Street / Strip. I'm currently using the Petronix coil since Ive read its good to match the coil and module when possible. I've no idea which coil is "better", but I did notice the black paint you mention - I know I sanded it off on at least one of them, but worth checking the other.
Question 5 - yes, not sure on exact RPM of fast idle but 1500RPM sounds about right,. It will come down a bit on its own and I can give it some quick throttle and it wall fall to curb idle.
Lifters - yes, I considered that, but with as much time as I've spent adjusting valves, I'm certain I'd have noticed any sort of inconsistent function or noise. They all operate in a similar fashion, with no noise over the standard engine sounds. I've even stethoscoped it a few times and the only thing I hear is my damned exhaust pipe clanging off the hole in the cross-member.
I haven't used a KV tester. I have used a few other spark testers, each with downsides. Tester 1: YOu set the gap to mirror the spark plug gap, then ground it to something, watch the spark jump, observe color and consistency. Downside - its not inside the engine and so not coping with the environment inside the combustion chamber, which can impact spark (or no spark) condition. Tester 2: An inline unit that flashes - downside is that I'm not sure its precise enough to pick up a single random miss here and there - the light is very dim to start with. Tester 3: a (sort of cool) little induction unit that you simply hold against a wire and if a spark happens, it flashes. The upside is its easy to use and you can test multiple wires in seconds. Downside is that I can;t be sure of its accuracy - i.e. sometimes it shows no flash, but the timing light is blinking happily on the same plug wire.
As for "real stretch" ideas - trust me, I'm there. I even disconnected the Tach because I read several cases where a malfunctioning Tach caused an HEI to malfunction. No the case for me, but I'm trying most anything at this point.
I've thought about a giant tinfoil hat....you never know.
08-22-2019, 09:12 PM
#44
1st Gear
Member Since: Aug 2019
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Noisey lifters under load
Don't give up. If you have to pull the motor apart to figure it out. You could let us know what was wrong and save a lot of people the same grief. I am a retired Gm mechanic and the problems I ran into I could not even count. One time we had customer come in and had a 1967 Impala that he had a 454 installed by another shop. The motor was rebuilt by a performance re builder. His complaint was the rocker arms were noisy and the shop could not resolve the problem. One of are mechanics worked on it and could not fix it. The customer picked up his car and I struck up a conversation with him. i told him to drop it off at my house and I would dig into it. I did every test I could think of with no luck. I felt that the oil pressure must be dropping off in the lifter galley. So said to my self I am going to take the timing chain cover and chain off an screw my oil pressure gauge in one of the lifter galley ports and run the oil pressure up with my Adapter and a drill to see what the oil pressure was at the lifter galley. What found was when I removed the galley plug I noticed there was a hole drilled in it. I checked the other galley plug and was the same. Now this is a mod that is done to supply more oil to the back of the timing gear so as not to wear the block. I have done this my self. I put a .043 drill hole in one galley plug. The plugs I took out had 1/8" holes drilled in each one. This was the problem. Losing oil pressure at the end of the galley. Engine oil pressure was good at the bottom end. I replaced the plugs drilling one small .043 hole in one galley plug. Put every thing together and valve train was quiet as a mouse. I don't know how many hours it took to get there but it was a lot. The point is there is a solution. Just don't give up.
I recently built a 74' 350 Chevy engine has good power and exc. Throttle response but under load and under normal temp about 185 degrees it has good oil pressure hi volume oil pump 25 at idle 50-60 cruising hits 75 cold at start up had strprofessional machine shop do the work used all new parts I put it together primed motor prior to start up oil at every rocker arm but when you run it hard sounds like on driver's side bank a lifter or 2 will start pecking lubed all lifter bored after cleaning engine is very strong and doesn't miss and oil pressure is still very good by the gauge running 7 qt pan valve train I used the larger pushrods as far as exterior long sloted rockers and all new springs, screw in studs cam and lifters during break In I used zinc additive and every oil change also it starts right up love it have it bored 030 /bal.and GM X rods trw forged pistons gm cast iron 2.02 heads Port and polish with matching polish and port on Torker Intake 650holley DP and headers any ideas would be great I am going to look at small block oil routing running hyd.camshaft bought as kit from summit
Last edited by Gary Gross; 08-22-2019 at 09:17 PM.
08-23-2019, 07:41 AM
#46
Race Director
look thru old threads to do research. then start a new thread with your question. if we don't notice age of first post, we read through 42 posts of old issue before we get to you. that being said, sounds like a couple of bad lifters. and please. punctuation.