New engines or rebuilts?

When is the last time you changed your oil? I would get a sample and have it analyzed. This will tell you what is wearing and if you have a big issue inside. Also, what brand oil filter are you running. I had a Sierra fail on me last year which made the oil pressure gauge do weird things. Lastly, a good mechanic will use a stethoscope to zero in on the issue. At minimum, pop a valve cover off and look at the rocker arms for play
 
yep. hydraulic lifters are not adjustable but do have to be set correctly. could have been the rockers that he tightened?

20psi is fine at idle. you only need 10 psi for every 1000 RPM. So 40 psi at 4000 RPM, etc. 7 PSI at idle is as low as I would want to see it and i get a little nervous when i see 15 at idle
 
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boatman37 said:
yep. hydraulic lifters are not adjustable but do have to be set correctly. could have been the rockers that he tightened
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It was a 1993 454. Tech took the valve cover off and used a feeler guage to check tension of the moving parts. Tightened and double nutted one and the noise went away.
 
the way i set hydraulic lifters was to put that cylinder on TDC on the compression stroke so both valves were closed then tighten the rocker until the push rod had no play in it then back it off about 1/2 turn. i have only ever used a feeler gauge on my solid lifter engines. but if it fixed your problem then all was good....lol
 
boatman37 said:
the way i set hydraulic lifters was to put that cylinder on TDC on the compression stroke so both valves were closed then tighten the rocker until the push rod had no play in it then back it off about 1/2 turn. i have only ever used a feeler gauge on my solid lifter engines. but if it fixed your problem then all was good....lol
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I believe if you “back off” 1/2 turn from zero lash you will have a very noisy valve train.

Of I remember correctly, you should tighten the adjustable rocker 1/2 to 1 full turn past zero lash.
 
To check your lifters on a non-adjustable valve train, you go through the process like they were adjustable. Tighten rocker bolt till 0 lash, then it should take between 1/2 and 1 1/2 turns before you torque to 40 #'s.
 
maybe it was 1/2 turn past 0 lash. been a long time since i have done it and the last 4 or 5 i did were all solid rollers. i do remember it was when you could just spin the pushrod. if you couldn't spin it then it was too tight but that certainly isn't an exact science...lol. last time i did one was probably late 1990's
 
I wish I were a mechanic. Next time I go out I'll try to go at full 4,000 RPM and see what happens. I have vessel assist coverage just in case.
 
majoma said:
I wish I were a mechanic. Next time I go out I'll try to go at full 4,000 RPM and see what happens. I have vessel assist coverage just in case.
Click to expand...

You could just run it WOT for a minute or so, then you will either need to adjust something of replace it. LOL

MM
 
majoma said:
I wish I were a mechanic. Next time I go out I'll try to go at full 4,000 RPM and see what happens. I have vessel assist coverage just in case.
Click to expand...
If your engine is 'talking to you' by making some noise, I wouldn't suggest going this route.

Where are you located? Maybe someone is local to you here that could come listen and give you some advice. Yes, 454s generally speaking are no nonsense, bulletproof motors. However, if you have a piston or valve issue, you're only exacerbating the issue and potentially doing irrevocable damage making a run like that. I would do some more diagnostic work first.

1. Compression check - If good, proceed on. Take notice of any plug readings and note the cylinder.
2. See if you can isolate noise to one bank or another. Pull valve cover on that side. Inspect and compare rockers to cylinder of plug reading/compression readings that may be indicative to problem area. You're potentially looking for loose rockers. If loose, start motor with some towels around and see if you can confirm that is the problem area. If so, while running tighten rocker nut until noise just stops and then 1/2 turn past. Go slow.
3. At this point you could also run a leak down test.


Report back.
 
#2 was the way old timers used to set rocker lash. It was how I was shown 45+ years ago. Now I tighten as I moved the pushed up and down and spin to remove all lash then tighten 1/2.
 
sdarc said:
#2 was the way old timers used to set rocker lash. It was how I was shown 45+ years ago. Now I tighten as I moved the pushed up and down and spin to remove all lash then tighten 1/2.
Click to expand...

I agree. However, I suggested this option because OP didn't seem to have extensive mechanical knowledge. This option would quickly determine if the noise was valvetrain related and whether it's strictly a loose rocker nut or worse a wiped cam lobe.
 
You're correct. 2000 is a gen IV 454 with non-adjustable valvetrain. Scrap the portion about tightening the rocker nut. However, everything else still stands to see if you can isolate the problem to a specific cylinder/rocker, etc.
 
douglee25 said:
You're correct. 2000 is a gen IV 454 with non-adjustable valvetrain. Scrap the portion about tightening the rocker nut. However, everything else still stands to see if you can isolate the problem to a specific cylinder/rocker, etc.
Click to expand...


Mine are 1997 GEN VI 454 I think IV ended in the early 90’s
 
Gen VI technically started production in 1996 to 2001.

I'm sure there isn't a hard cut off with the boating industry however.
 
Believe it or Not, this didn't make any noise... Just bad performance. Couldn't hit WOT and was slow to come up to 3200 RPM..3 rollers failed on the lifters which intern wiped the cam.. The rest of the motor was perfect after 3500 hours.

20170915_203814.jpg
 
There is a hard cut off with the engine numbers. Gen 6 started in 96 with engine F800700. Gen 4 ended in 91.
 
I had a 454 in my '69 Chevelle pushing about 650 HP with a roller. The link bar on a lifter set broke and the lifters were rotating and wiped 2 lobes off my cam. It was a .685 x .692 lift Lunati cam. Couldn't get the broken lifters out so yanked the motor to spend more time with it and ended up trading it for another engine so not sure how the next guy got the lifters out.
 
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