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1990 Ford Mustang LX 351M powered!! Project Cherry Bomb!!
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Just thought of something... Is it more apt to do it when it's cold and calms down when it's hot? I mean it may not go away completely, but it's not as bad when it's warmed up/hot? I'm thinking it might be piston slap possibly?? How many miles on the block and the pistons? I know you said you just rebuilt it, but that doesn't say how many miles are on those parts... It's still holding oil pressure, so that throws off the bottom end, that's why I'm wondering about piston slap, worn pistons or worn bore that should have been bored out and had replacement pistons put back??
 

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Discussion Starter · #23 ·
Just thought of something... Is it more apt to do it when it's cold and calms down when it's hot? I mean it may not go away completely, but it's not as bad when it's warmed up/hot? I'm thinking it might be piston slap possibly?? How many miles on the block and the pistons? I know you said you just rebuilt it, but that doesn't say how many miles are on those parts... It's still holding oil pressure, so that throws off the bottom end, that's why I'm wondering about piston slap, worn pistons or worn bore that should have been bored out and had replacement pistons put back??
I can hear it upon startup and Ive ran it probably 10-15 mins and still hear it. The knock is pretty consistent throughout startup-running for 10-15.

I couldnt tell you how many miles the 460 actually has.

It was in the 55 when I bought it. I had a machine shop rebuild it, go over everything. Bored 30 over, still have all my printout from this AERA Engine Builders Assoc they gave me with all the specs.


Im just confused as to why it happened when I put my intake manifold back on....Extreme coincidence or did I jack something up. :(

Really appreciate all the help everyone!!!
 

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Ahhhhhhh..... I might be calling the machine shop at this point as well and yanking on their chain as to the noise and the antifreeze situation... You shouldn't be getting something like this from a machine shop that will give you a builder sheet with the build.. I'd get on the horn to them about it... A good shop should stand behind their work and help you out at least with some more troubleshooting or testing...
 

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HI,, Check the push rod on that loose rocker.. roll the motor to where the opposite rocker #8 is starting to open the valve take off the #7 rocker and pull out the push rod roll it on a flat surface and see that it does not wobble also check the ends for being squashed.. Post picture if you can

good luck take care be safe
tim
 

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That is a real knock. I didn't know what you were describing before.
I don't think the intake change is related.
You might check and make sure a torque converter bolt hasn't backed off as sometimes they will with time and sound like an engine knock.
Good luck
Greg
 

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Discussion Starter · #35 ·
All,

Checked Torque Convertor bolts...All seemed pretty tight. I cinched them down a bit. Still knocking.

I put my mechanics stethoscope on my oil pan, I dont hear any loud knocking coming from the pan either.

Running 10/40 Engine oil. I did put some cheap O'riellys House brand oil in it while I was making sure I didnt have any antifreeze leak. Later I was going to fill it up with something better. Castrol or something.
 

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Total shot in the dark....I changed my passenger side valve cover gasket from a cork gasket to a rubber one.

Could the rubber gasket be just slightly less thick than the cork one causing the rockers or something to ping on the valve cover?
Pull your cover and see if there is any evidence on the inside of contact. I have the same block and heads, thought I had an engine ticking but found my #4 exhaust manifold bolts were loose. With the AF situation you may have a slight crack starting in the block somewhere. I rebuilt a 1967 Buick 225 back in the 80’s and cleaned off all the gunk, new piston rings, valves the works. Fired it up and cracked the block. I think the gunk was holding it together - lol.
Best of luck, hope it’s a simple find and fix for you.
 

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Discussion Starter · #37 ·
Pull your cover and see if there is any evidence on the inside of contact. I have the same block and heads, thought I had an engine ticking but found my #4 exhaust manifold bolts were loose. With the AF situation you may have a slight crack starting in the block somewhere. I rebuilt a 1967 Buick 225 back in the 80’s and cleaned off all the gunk, new piston rings, valves the works. Fired it up and cracked the block. I think the gunk was holding it together - lol.
Best of luck, hope it’s a simple find and fix for you.

Ive got Sanderson Headers installed......I did have one slightly loose, but that wasnt it. I fired it up and still have a knock....

Hahaha....Dont jinx me. Started out as a small AF leak, turned into a knock after I got it all sealed up.

So to recap:

Ive checked my rockers.---
7th one back on the drivers side was a little wiggly(could have been me and no trouble). I checked the rod and no trouble. I tightened it back down.

Checked the valve covers---all seemed ok, I didnt notice any rubbing on the underside.

I put my mechanics stethoscope on valve covers, oil pan, intake, cant hear any definitive knocking culprit.

Ive checked All Torque Convertor Bolts.

Checked all the Header bolts
.



Any other ideas what I can do to diagnose it?
 

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Place your hand on the block as it's running, when it's cool preferably, if you can feel it thumping down low on one side or the other, you know which side it's really coming from and how solid it feels... This is a lil more info you can use to report back to the machine shop... I'm sorry to say it's prolly time to bite the bullet on this one and give em a call.. if you're still in decent contact with em maybe have one of the guys from there come and give it a listen, unless they are like 3-4 hours away...
 

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Discussion Starter · #39 ·
Place your hand on the block as it's running, when it's cool preferably, if you can feel it thumping down low on one side or the other, you know which side it's really coming from and how solid it feels... This is a lil more info you can use to report back to the machine shop... I'm sorry to say it's prolly time to bite the bullet on this one and give em a call.. if you're still in decent contact with em maybe have one of the guys from there come and give it a listen, unless they are like 3-4 hours away...

I figured it would be time to take it somewhere. I wouldnt say Im in decent contact with the machine shop. I was a customer almost 20 years ago, paid them money. I can roll by there and play my video off my phone.

Ive had small amounts of antifreeze in my oil for quite some time, so I would assume the intake manifold gasket was askew since it was put on , so Im reluctant to take my engine back to the same shop that put it together. And dont get me wrong, I know good mechanics make mistakes, but Im still leary.
 
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