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Unread 05-26-2013, 05:21 AM   #1
jr4x4
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fast rattle at first start

good morning JF. its a fast clatter/rattle noise that lasts for maybe 2 seconds only at first start of the day. I just got jeep 3 months ago & done allot to it & don't remember this noise until I did these changes. 1990 4.2 tf999. . I did team rush W-MSD coil, weber 32/36 carb, nutter bypass, new icm and new pre smog dizzy, and complete tune up. ever since the carb & dizzy is when I got this noise. oh and what sounds like wrist pin also. when I rev engine ONLY in park or neutral with no load I get a clatter noise. ( like 2 pieces of wood rattling together) only as rev increases. that came only after new dizzy. ive adjusted & adjusted some more. engine idles great. I pulled all plugs & they all look the same & look great. just these two different noises. im guessing lifters maybe on the cold start. it didn't do it before new parts though. oh I pulled valve cover also & all looked fine. off & at idle. sorry if this sounds confusing. im typing fast. I have my 3 year old hanging off my head as I type. thanks guys...

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Unread 05-26-2013, 05:30 AM   #2
rebelbowtie
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Your rattling if it sounds like it is internal sounds like piston slap to me, if it is something outside the engine I would guess a loose flexplate or fan. In my experience lifters make a loud tick and not a rattling sound.
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Unread 05-26-2013, 05:41 AM   #3
jr4x4
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yea i was starting to think maybe flexplate. i checked converter bolts and they are tight. the cold start noise is like a fast clatter. makes you cringe.lol. like a tink sound almosr like all 12 rockers hit the valve cover one time around . fast. if that makes sence. thanks for the fast reply.
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Unread 05-26-2013, 10:17 AM   #4
Old4X
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Could be worn rod bearings. Easy to check is drop one qt of oil from pan and replace with a qt of Lucas. If noise is gone, you need to fit new rod bearings to the crank.
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Unread 05-26-2013, 01:31 PM   #5
jr4x4
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just did oil change yesterday. went from 10-30 to rotella 15-40 with lucas. still very clear clatter at startup. only when engine is completly cold. other than that it runs great. it sounds more near the top end. like number 6 on exhaust manifold side. i just got my whole exhaust done so itd not that.
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Unread 05-26-2013, 06:37 PM   #6
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The lifters tend to bleed down and tick at first start up.

If you have ever heard a rod knock, you can easily tell it from a dry lifter, both can occur at cold startup.

These are ancient engine designs, and they tend to knock and tick some. Usually will go 200,000 noisey miles with little problem.

If you have a sudden increase in noise, that is when to be concerned.
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Unread 05-28-2013, 07:44 AM   #7
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ok the rattle jappens every time engine cools then started. but the rattle stops as soon as my oil gauge rises. why all of a sudden this noise after new weber, dizzy. how can i stop this. i did use my old dizzy gear as well. oil pressure is like 40 cold & about 20ish hot idle
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Unread 05-28-2013, 09:26 AM   #8
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Mine bleeds down when cold. When I think about it, I just hit the starter without setting the choke. A few rpms and oil gets where it needs to be, hit the choke and I get a quiet start.

As you have changed engine components, it may be revving faster when first started and before you have oil pressure causing more noise than before.
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Unread 05-28-2013, 09:43 AM   #9
jr4x4
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Quote:
Originally Posted by Old4X View Post
Mine bleeds down when cold. When I think about it, I just hit the starter without setting the choke. A few rpms and oil gets where it needs to be, hit the choke and I get a quiet start.

As you have changed engine components, it may be revving faster when first started and before you have oil pressure causing more noise than before.
thats what ive been trying to do. i have a electric fuel pump so i turn key pump pedal and turn key and let it slowly stumble to life then get the revs up. it still makes the noise but not half as loud. this has got to be damaging something. when i had valve cover off & started up it took maybe a second or two for oil to rise from pushrods. could this be a bad oil pump. engine has 175000 . im sure its the stock one. just dont have time to be droping pans if i dont need to. thanks allot old 4x for your input. sorry on spelling....
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Unread 05-28-2013, 11:30 AM   #10
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Dropping the pan takes less than 15 minutes. The oil pump is just hanging in the breeze. If that is what you think it is, it isn't a big job.

Having been into mine, I would guess you have excessive rod bearing clearance, causing oil pressure to build slowly. drop the pan and plastiguage the bearings and you will know for sure.

These are tough engines, but will toss a rod through the block if allowed to get too loose.
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Unread 05-28-2013, 01:12 PM   #11
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My buddies 89 does the exact same thing
I let the starter turn about 10 times then set the choke
Fires up quiet each time
We did pull the pan thinking the oil pump was bad and making the noise
The pump was wore and got replaced but the noise is still there
Piston slap was all I could figure
The crank and rod journals are tight
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Unread 05-28-2013, 01:26 PM   #12
jr4x4
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Quote:
Originally Posted by zeus87gn View Post
My buddies 89 does the exact same thing
I let the starter turn about 10 times then set the choke
Fires up quiet each time
We did pull the pan thinking the oil pump was bad and making the noise
The pump was wore and got replaced but the noise is still there
Piston slap was all I could figure
The crank and rod journals are tight
wow dude thats kind of good news. maybe im going to dtop pan tomorow i think. thanks
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Unread 05-28-2013, 01:51 PM   #13
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It was a good thing
Not only did we verify what was and wasn't going on,
but we also cleaned some of the nastiest stuff I've seen from the pan
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Unread 05-28-2013, 02:31 PM   #14
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Originally Posted by zeus87gn View Post
It was a good thing
Not only did we verify what was and wasn't going on,
but we also cleaned some of the nastiest stuff I've seen from the pan
Did you have brown crunchies that came off the cam gear? (the nylon teeth for those that haven't seen it yet).
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Unread 05-28-2013, 02:43 PM   #15
jr4x4
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how could the engine bleed down of oil after a little while? and again didnt seem to do it untill i installed weber carb and pre smog dizzy. playing with advance dont seem to change nothing. so maybe air fuel ratio causing some kind of detonation. that just dont sound right.
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