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****UPDATE****1.5 year old engine knocking slightly, please please help me!

Discussion in 'The Garage' started by dawson444, Feb 5, 2003.

  1. dawson444

    dawson444 1/2 ton status

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    /forums/images/graemlins/angryfire.gif /forums/images/graemlins/angryfire.gif /forums/images/graemlins/angryfire.gif /forums/images/graemlins/angryfire.gif
    I got a 350HO from GM about a year and a half ago, I am not 100% sure of how many miles I have on it, not many at all, it is not a DD. It is now slightly knocking from the oil pan, not as bad as when I blew my old 350, but it is doing it slightly. It does it pretty bad when it is cold and I have just started it, but it still does it once it has been running for a few minutes. Simply put, anyone have any ideas? I was thinking pull the oil pan and see what I see. Please help me! Thanks!

    ---UPDATE---
    Let my mechanic look @ it, he said he said it wasn't the convertor like he though. He said it was the engine. He said it didn't sound like a main bearing, he said he thouht it could maybe be a wrist pin or something else. Anyone know what to do now? Going to go talk to chevy dealer and see what they say, not expecting anything though.
     
  2. great scott

    great scott 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    Not good. Sounds like youve allready nailed it down to a bearing. But just to be sure if your running an auto check the flex plate bolts. If you have a carb and mechanical fuel pump make sure thats not knocking short of that its bearings. /forums/images/graemlins/confused.gif
     
  3. heavy4x4

    heavy4x4 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    Still under warranty?

    Sounds like bearings are already getting worn/sloppy (if it's rod knock). Call GM or the place you bought it from (or where it was installed) before you touch a bolt on it. If it still has a warranty, they sometimes won't honor it if the engines been tampered with. If you do decide to drop the pan and have a look - look for scuff marks/indentations on the rods and lower parts of the cylinder walls. That would be rod knock. Otherwise, unless you're willing to take it apart futher, you're not going to find much else that could be wrong with it.
     
  4. dawson444

    dawson444 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    As far as the warranty was concerned, it was 12mo, 12k mile, 12mo is up. It was parts only I believe. As far as the flex plate bolts are concerned, you think just check to see if they are loose? If that not it, you all think drop the pan and have a look? Lets say it is bearings, what do I need to do to replace them or fix it? BTW- it is FI, not carb, so no fuel pump. Anything else? Thanks!
     
  5. great scott

    great scott 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    Yes make sure the flex plate bolts are tight and that the plate its self is not cracked. Asuming it is bearings you should have the cranck turned down and then run an oversized bearing to compensate. If it makes you feel any better I am replacing a hole FF14B becase a bearing chewed up my spindle and tube.
     
  6. dawson444

    dawson444 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    I checked flexplate bolts and flexplate tonight. They seemed fine. I am going to mess w/ the timing tomorrow, that could maybe be it too. It wasn't running that great before it happened. Any other help? Thanks!
     
  7. pismorat

    pismorat 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    OK, I have a 406 smallblock that I did a lot of after-market work to. One thing I did was put in a high volume oil pump. This is not good for offroading because it keeps too much oil in the top end and not enough in the crank. Don't confuse high volume with high pressure, pressures can be changed by the change of a spring. What ended up happening is identical to what you are describing. I off roaded a lot, it kept getting worse and I never had time to look at it. So I was driving through LA and spun the No. 1 crank bearing. Needless to say I needed all new bearings, new crank, and oil pump. So see what the specs were on that pump, then pull the pan and check tolerances on a few of those bearings. It seems like a lot of work, but it is way better to catch it now before it is too late...TRUST ME! /forums/images/graemlins/truck.gif
     
  8. ZonkRat

    ZonkRat 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    If not running right meant it seemed like it was in a strain or something was holding it back,could very well be bearing trying to seize on you.LOL.
     
  9. dawson444

    dawson444 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    When I say not running right, I mean idling like crap. I know it has a hi pressure, not sure about hi volume, where should I look for that? I would guess dealer would know, what specific spec should I ask for for the pump? How should I go about checkng the specs on some of the bearings? Thanks!
     
  10. ZonkRat

    ZonkRat 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    If the rear main is trying to seize it could cause higher than normal pressure cause its makeing clearance tight on bearing. /forums/images/graemlins/thumb.gif
     
  11. 4DiggerDan

    4DiggerDan 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    Its okay... Not many guys out there actually know what a high volume pump is intended for. When you build a real race engine, you make sure you have extra clearance in the rods and mains so that the rotating assembly has a thicker oil wedge to ride on. This is a good idea in a race car because you're off and on the throttle pretty aggresively, and "loose engines run faster." In that application, since the fit on the rods and mains is looser, more oil falls back into the crank case. You therefore need a higher volume of oil just to GET oil to the heads. If your stock Chevy oil pressure gauge is pegged all the time and you have a stock pan, you're going to wind up with all your oil in the top end and chuck a bearing. In a race engine with a high volume pump, I usually like to see about 50 Lbs at 5 grand, then you can use a smaller hole in your push rods to limit the amount of oil that gets into the heads. In a 4 digger, use a stock pump.

    High pressure pumps I really haven't monkied around with enough to know what that animal is all about.
     
  12. ZonkRat

    ZonkRat 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    I agree with that.Lots of folks think pressure is the important thing.Would rather have the extra volume any day.I'm lucky on my motor,it has over450,000 miles on it and still runs good.Smokes a little when twisted over bout 3000,but,only uses bout 2 quarts in 3000 miles.Only thing done to it is timing assem and normal maint. /forums/images/graemlins/crazy.gif /forums/images/graemlins/truck.gif /forums/images/graemlins/thumb.gif
     
  13. wayne

    wayne 3/4 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    Here is a little tidbit on small block oiling. The regular volume pumps are plenty for almost any small block, where they are better off is with more pressure.
     
  14. Blaze

    Blaze 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    I thought you got a 383? That really sucks about that motor. Too bad I'm not in Raleigh anymore or I'd help ya out again. Might want to talk to Blair again if you need some serious work.
     
  15. swamp ratt

    swamp ratt Registered Member

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    I HAD A PROBLEM WITH AND 87 LWB I HAD WITH A 350&700R4 TRANNY A PLANTARY GEAR SET HAD GONE BAD IN THE TRANS CAUSING WHAT SOUNDED LIKE A BOTTOM END KNOCK. /forums/images/graemlins/shocked.gif
     
  16. dawson444

    dawson444 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    I checked the flexplate bolts. They all look fine, and the flexplate didn't look cracked. Anyone know of a good place to go for reference on how to do the bearings? Also if I end up pulling the pan this weekend, anything to look for or be careful with? Thanks!
     
  17. Geno

    Geno Registered Member

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    I recently bought a suburban with a 350 goodwrench motor in it, was going to put the motor in my Jimmy, had about 20,000 miles on it, thought how could I go wrong with a crate motor? Pulled the pan was going to put a new oil pump in it for good measure, was looking things over when I noticed the crank moved back and forth quite a bit, put a gauge on it, it moved about 60/1000, you could see where the crank was being pushed forward and hitting block, thrust washer was about gone on the crank, took it to the shop, the man said torque converter expanded causing the crank to be pushed forward, this can happen when running high RPM.crank was ruined, bearings were wore too. Also found out all GM crate motors are made in mexico, heads too, stamped right on the block. I question the quality of those motors. Anyway thats my two cents, something to check.
     
  18. 89K1500Chevy

    89K1500Chevy 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    wow now thats a good reason to go get a bill mitchell HARDCORE RACING PRODUCTS crate motor.........well mabey not but that would kick ass if you got that much money to throw at an engine... I got my crate engine from Precision Engines 3 year, 300,000 mile warrenty i thought it was 100,000 till i looked at the sheet last night but the 3years is up and its still running great. /forums/images/graemlins/deal.gif /forums/images/graemlins/truck.gif /forums/images/graemlins/usaflag.gif www.zombieoffroading.8m.net
     
  19. ZonkRat

    ZonkRat 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    May not help,but,heres another thought.Use a peice of 1/2 of pvc pipe for a stethoscope to listen to noise.Helps to zore in on exactly where the noise is.Might get lucky and have carbon buildup on piston.I have seen this happen and it's worth checking.Will cause light knock at low RPMs.Shade tree trick,but,sometimes it helps.LOL. /forums/images/graemlins/thumb.gif
     
  20. dawson444

    dawson444 1/2 ton status

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    Re: 1.5 year old engine knocking slightly, please please help me!!!

    Local mechanic crawled under it yesterday, he said he didn't think it was the engine. He said he thought it was the torque convertor. Anyone have any ideas? How to see if it is coming from convertor? He said to bring it back next week and he would put it up on a lift and listen to it better. Anyone have any ideas? Thanks!
     

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