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install intake and now knock

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Old 03-11-2010, 05:32 PM
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install intake and now knock

I installed a holley and performer package along with replacing the TFIIV ignition with a duraspark 2. I broke a bolt on the head and now can only secure 11 bolts instead of 12 and now it knocks. The knock is low and hollow not a ping or rattle. What could go wrong with this bolt not secure and could the knock be from it somehow? I never had this up unitll now and I dont have water in the oil, but I see moisture coming out of the tail pipe in the morning.
 
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Old 03-11-2010, 06:27 PM
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Water is a naturally occurring by-product of all internal combustion engines. In the damp morning air, the naturally occurring moisture condenses on the tailpipe as the hot exhaust gasses hit the cold damp air. If you are concerned that it could be contributing to your performance you can run a bottle of fuel system dryer in the gas tank along with your fuel.

The knock could be any number of things. I'd go back and check anything that you took a wrench to during the installation of the new parts and double check against torque specs for those parts. If you had the heads off, you could have a push-rod not fully seated (which probably means its bent by now). These are just the first few things that come to mind.
 
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Old 03-11-2010, 07:38 PM
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Thanx, best advice so far. I was thinking mabye main bearings but I could be low on oil now I'm leaking like a sive right now, could this lead to low oil pressure too? I'm changing the oil pump and pan seal anyway.
 
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Old 03-11-2010, 07:43 PM
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Knocking associated with low oil pressure is scary. The concern is spun bearings. How low is low?
 
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Old 03-11-2010, 09:15 PM
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well I replaced my oil guge with an after market but im not sure how accurate it is because it continues to drip. But the pressure is around 55 at startup and at warm its under 10 at idle, hard to tell exactley. When im at 2000 rpm the pressure reads about 15-18. I just want this knock gone, I'm almost to the point of bringing it to the shop.
 
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Old 03-11-2010, 11:31 PM
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Figure 10 psi per 1000 rpm approximately... which would put it low at 2 grand.
 
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Old 03-12-2010, 09:09 AM
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Oil pressure when warm should be 20-25 idle and 55-65 at 2500 rpm. If the pressure drops from 55 when cold to less than 10 when warm, then there's too much clearance in the bearings. If the oil pump has worn out and is failing to supply enough pressure, then I'd have to guess that the bearings aren't looking any better. I'd suggest installing new main and rod bearings at the very least.

Greystreak is correct on the rule of thumb; oil pressure requirement of 10 psi for every 1000 rpm. If for example, you're revving the motor to a max of 5500 rpm, like most street motors, then you better have 55 psi of pressure or you'll break through the oil layer on the bearings, and cause excessive wear. On the other hand, too much oil pressure and volume can also be bad. This is one case where overkill is not the best policy.
 
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Old 03-18-2010, 06:01 PM
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My father-in law did a 96 power stroke from underneath without removing the engine. Is this possible in a 351W? If I pull it than I'll have it rebuilt.
 
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Old 03-19-2010, 12:18 AM
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You can replace a pan gasket if you are careful without pulling it but I you can't get enough clearance to get the pan completely out if I recall correctly. I could be wrong and it depends on how much you take apart on top to give you "wiggle" room.
 
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Old 03-19-2010, 07:17 AM
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I've done an oil pan in a vehicle before, and it sucks. I think I had to jack up the motor to clear the crossmember. Installing that wiggly gasket in a perfectly clean manner is important to a good long lasting seal, so I would highly suggest pulling the motor and doing the rebearing and sealing and all on a stand. If the compression is good, and it's not using any oil, you could just slam in a polished crank and some rod and main bearings, a new oil pump, double roller timing chain, cam, lifters and go. You could even pull the pistons, check the skirts, and if they look good, and there's very little ridge at the tops of the cylinders, just hone 'em out, clean up the pistons and re-ring them. (mark the pistons so they go back in the same holes they came from) There's options for budget rebuilds, boring and new slugs isn't always a necessity.
 
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Old 03-19-2010, 10:22 AM
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If you have a bearing knock, it would be a rare deal for new bearings to fix the problem.
Usually by the time one starts knocking the crank needs turned and the rod needs resized. The bolt in the intake manifold also needs drilled out and replaced it will never be right missing a bolt, there is a reason for the torque sequance and specs.
 
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Old 03-19-2010, 11:24 AM
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just curious how many miles on the motor and what brand oil filter are you using? also what weight oil?
 
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Old 03-21-2010, 01:57 PM
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We need to look back at the sequence of events that took place before the knock started. He said that he broke a bolt when installing the manifold and could only use 11 of the 12 bolts; then when it was all put together that way he had a knock that he didn't have before.

Whether or not he has low oil pressure or oil leaks is not relevant to the knock because those conditions were present before the work was done and the bolt was broken. Anyway it sounds like his oil pressure is ok, based on the readings he reported.

The knock is almost assuredly related to the broken bolt. What he -should- have done was to repair the broken bolt before installing the new intake. The manifold should not have been installed without the stud being repaired. The "knock" that he is hearing is most likely a small vacuum leak related to the missing bolt. I believe that if he removes the manifold, repairs the bolt, and replaces the manifold with new gaskets and proper torque etc. then the noise will be gone (as long as the manifold is not warped or cracked, which is a possible consequence of installing it without the twelth bolt. I'd have it checked out by a machine shop before reinstalling it).
 
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