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11-22-2010, 09:08 PM
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#1
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Junior Member
Join Date: Nov 2010
Posts: 8
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454 Rattling Issues
Hello,
I just rebuilt my 454 and it has a slight rattle under load, in the 2k and up rpm range. sounds like someone shaking a spray paint can. It doesn't sound like an low octane ping. it seams like its coming from #7 cylinder. all parts are new in this motor besides the pistons. cylinders were within tolerances for honing and new rings. could it be a valve floating? or broken spring? also wouldn't pinging come from the whole engine? also I can just rev it up and here the same chatter!
any info would help lots, and thank you! everything I have searched for everyone says pinging, I'm running 91 octane and 7 pt octane boost.
eng:
Gen v, hydrolic cam and lifters, and this isnt in a motor-home its in a truck but searching all over the internet the most helpful guys for a 454 is either motor home guys or boat guys.
Jason
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11-22-2010, 09:36 PM
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#2
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Registered User
Vintage RV Owners Club Gulf Streamers Club
Join Date: Oct 2010
Location: Indiana
Posts: 4,951
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If it really is coming from a cylinder, more than likely one of your lifters is collapsing.. Did you reuse them or the cam? Did you soak them in oil overnight before putting them in? Did you use cam break in lube? Pull the valve cover(s) and using a timing light with the engine running, look at the rocker and push rod. It should be fairly steady and in the same place every time the light strobes..Trigger the light from the cylinder being looked at, and the ones just before and after in the firing sequence to see it at different stages of lift.. You can get little splash shields for the rockers (use when lashing solid lifters/rockers) to help keep the oil from slinging all over.
Or you could just change them all out again
The other thing to double check is to make sure its not something on the front end, like the chain, a tensioner, etc. Or on the back end - flexplate, converter, etc.. Noises have a way of traveling. A stethoscope is a good tool to use here..
Good Luck!
Edit: oh.. and you know that a 'point' of octane boost equals 0.1, right?
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11-23-2010, 05:45 AM
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#3
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Senior Member
Workhorse Chassis Owner
Join Date: Sep 2007
Location: st.charles mo.
Posts: 1,482
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When overhauling any engine the piston to cylinder wall clerance should always be checked. The 454 has had a problem with this and more so if it had been overheated. I have never overhauled any big block chevy motor without replacing the pistons.
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11-23-2010, 10:37 AM
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#4
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Junior Member
Join Date: Nov 2010
Posts: 8
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Quote:
Originally Posted by Midniteoyl
If it really is coming from a cylinder, more than likely one of your lifters is collapsing.. Did you reuse them or the cam? Did you soak them in oil overnight before putting them in? Did you use cam break in lube? Pull the valve cover(s) and using a timing light with the engine running, look at the rocker and push rod. It should be fairly steady and in the same place every time the light strobes..Trigger the light from the cylinder being looked at, and the ones just before and after in the firing sequence to see it at different stages of lift.. You can get little splash shields for the rockers (use when lashing solid lifters/rockers) to help keep the oil from slinging all over.
Or you could just change them all out again
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Thank you I'll have to try the timing light, unfortunately they are aftermarket lifters and the oil tabs for not letting the oil fly all over the place dont fit so oil will have to just fling away. it happens at 2700 to 3000 rpm in every gear load or not!
I wanted to replace the pistons but was assured they were ok and I was trying to save a buck! their is no chain tensioner and the flexplate is new.
Is there any particular plug wire the timing light should be on?
the lifters sat in oil for over a month, the cam and lifters are new, they are Lunati voodoo cam, and Lunati lifters. like I said everything is new inside the engine except the pistons, the heads we reused edlebrock aluminum heads.
Jason
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11-23-2010, 11:37 AM
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#5
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Registered User
Winnebago Owners Club
Join Date: Oct 2009
Posts: 848
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I dropped # 7 cylinder, Cracked the skirt out of the piston; Then I put the after market upgraded pistons in , Much better; I should have done it the first time.. NEVER overhaul a 454 without replacing the pistons;;
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11-23-2010, 11:39 AM
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#6
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Junior Member
Join Date: Nov 2010
Posts: 8
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Quote:
Originally Posted by speed racer
When overhauling any engine the piston to cylinder wall clerance should always be checked. The 454 has had a problem with this and more so if it had been overheated. I have never overhauled any big block chevy motor without replacing the pistons.
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the engine didnt over heat, It had lots of miles on it, and the cam bearing were worn out! also the pistons are forged racing pistons, still in xlint shape!
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11-23-2010, 04:29 PM
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#7
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Registered User
Vintage RV Owners Club Gulf Streamers Club
Join Date: Oct 2010
Location: Indiana
Posts: 4,951
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Quote:
it happens at 2700 to 3000 rpm in every gear load or not!
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Does it happen only at that rpm range, or is that when it starts? You could be having a harmonics issue (resonance) if only in that range. You could try swapping springs with another cylinder.
Quote:
Is there any particular plug wire the timing light should be on?
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You can try several plugs to see it in action at different lifts. If you use the cylinder your looking at and the next/previous one in the firing order, you might be able to seeing if you have 'valve bounce' - a bouncing of the valve off the seat that would indicate a bad spring.
Again, this is if the noise is actually coming from a cylinder..
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11-23-2010, 07:24 PM
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#8
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Senior Member
Join Date: Feb 2010
Location: Sunnyvale, CA
Posts: 1,195
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I hate to suggest this... but drop the oil pan and double check the main bearing caps. Cut the filter open and check it as well. A high speed rattle sound could be something ugly. My guess is lifter, though.
Steve
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12-30-2010, 04:20 AM
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#9
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Member
Join Date: Nov 2010
Posts: 47
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Check for rattle in muffler, could be loose baffles.
Look at all accessories for loose bolts or worn out bushings. Some alternators had plastic bushings that would disintegrate with age and make noises that would convince you that rods were knocking.
One of the biggest failures of "rebuilds" is not replacing valve keepers and springs.
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12-30-2010, 08:39 AM
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#10
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Senior Member
Newmar Owners Club
Join Date: Apr 2010
Posts: 460
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You might try removing #7 plug wire for diagnosis (as well as #8&5), if the sound changes when that cylinder is not firing you've at least isolated the problem. A loose bolt(s) between flex plate and converter can also cause a rattle.
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12-30-2010, 08:52 AM
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#11
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Senior Member
Vintage RV Owners Club Fleetwood Owners Club
Join Date: Dec 2009
Location: CA
Posts: 1,268
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To help pin point the noise, try killing the cylinders one at a time. Did you turn the crank and check the tolerances?
J
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12-30-2010, 09:45 AM
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#12
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Senior Member
National RV Owners Club Freightliner Owners Club
Join Date: Oct 2009
Posts: 1,875
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Quote:
Originally Posted by trpwire
One of the biggest failures of "rebuilds" is not replacing valve keepers and springs.
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Tell me about it. Had a nice 56 Chevy 2 door that I put a full race 327 in. The short block was new, heads reused but didn't replace the springs. Dropped a valve and broke the block.
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2011 Jeep Wrangler Unlimited Sport
Officially fulltiming. The Journey Begins
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12-31-2010, 08:44 PM
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#13
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Member
Winnebago Owners Club
Join Date: Nov 2010
Posts: 34
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Jason ck the heads they could be warped and causing the rocker to ping the head. Alumnum is prone to that.
Quote:
Originally Posted by rockrdr
Thank you I'll have to try the timing light, unfortunately they are aftermarket lifters and the oil tabs for not letting the oil fly all over the place dont fit so oil will have to just fling away. it happens at 2700 to 3000 rpm in every gear load or not!
I wanted to replace the pistons but was assured they were ok and I was trying to save a buck! their is no chain tensioner and the flexplate is new.
Is there any particular plug wire the timing light should be on?
the lifters sat in oil for over a month, the cam and lifters are new, they are Lunati voodoo cam, and Lunati lifters. like I said everything is new inside the engine except the pistons, the heads we reused edlebrock aluminum heads.
Jason
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01-01-2011, 11:31 AM
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#14
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Junior Member
Join Date: Nov 2010
Posts: 8
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Quote:
Originally Posted by Beast1989
Jason ck the heads they could be warped and causing the rocker to ping the head. Alumnum is prone to that.
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The motor is a fresh rebuild, I had the heads resurfaced before I put it back together. there is less than 3000 miles on this motor!
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