Rod knock on an engine with 4000 miles??????

[highperf4x4]

I can tell you real quick how to check the main bearings and rod bearings. If you have a garage pull the front of the truck inside the door. If not, put the passenger side as close to your house or other wall/fence as you can get it and roll the window down. Bring the engine up to a constant 3000 rpm. After a couple of seconds, let up on the accelerator only SLIGHTLY so that it doesn't drop more than a few hundred rpms. Do this several times. If it's a rod or main it will make a dinstinct clanking noise each time you do it. A loose torque converter will also do the same thing however, you said it does it under a load and a torque converter usually will not so I'd rule that out for now.

With the engine idling, you can also take a wooden handle (like a broom handle minus the broom) and put one end against the engine block and wrap your hand around the other end (flush with the end) and then lay your ear on it like listening through a wall. If you have something knocking you will hear it through the handle and this saves you having to buy anything to listen with.

Not to throw a damper on anything but if your oil pressure is varying from 30lbs to 70lbs, you have a main bearing problem. It could be a gauge malfunction though so who knows.

[71 super]

Do you lose pressure when you accellerate and gain pressure when you let off the gas. If yes to either of these pull the motor the lower end is trashed and crank and bearings with line bore are in your future.

[americanmusc1e]

Originally Posted by 71 super

Do you lose pressure when you accellerate and gain pressure when you let off the gas. If yes to either of these pull the motor the lower end is trashed and crank and bearings with line bore are in your future.

not really. when it starts acting up it just drops the oil pressure down but it still acts normal

[Green Machine]

Why Marvel Mystery oil in a new engine ? Isn't that some pretty thin stuff ?

[brad_man_72]

last monday my engine started knocking. i pulled the steel crankshaft out in 3 pieces.
try turning flywheel/crankshaft back and forth and see if harmonic ballancer moves the same.

hell i didnt even think a car could run with a broken crankshaft.

a few pics of the carnage in my album. 5.3 swap in progress.

[highperf4x4]

Originally Posted by brad_man_72

last monday my engine started knocking. i pulled the steel crankshaft out in 3 pieces.
try turning flywheel/crankshaft back and forth and see if harmonic ballancer moves the same.

hell i didnt even think a car could run with a broken crankshaft.

a few pics of the carnage in my album. 5.3 swap in progress.

Yeah I rebuilt a Ford 302 with a broken crank. We started it up just before I pulled it and it sounded awful. It ended up being the wrong year model crank for the motor it was in. Someone had used an early model 302 bottom end in a later model station wagon and had to use the late model balancer which was balanced different. Typical Ford crap.

[special-K]

So,when are you going to look at the oil for metal.I keep saying this because you really need to know if it`s damage of improper assembly,as in beyond tolerances rom the get-go which is absolutely on the builder.I`ve had this happen.The bearings were .02 beyond.The guy took just a tad too much off and should have gone one more size under.

[americanmusc1e]

Originally Posted by Green Machine

Why Marvel Mystery oil in a new engine ? Isn't that some pretty thin stuff ?

to thin down 4 quarts of 20w50 (which i run because i have a flat tappet camshaft)

[americanmusc1e]

Originally Posted by special-K

So,when are you going to look at the oil for metal.I keep saying this because you really need to know if it`s damage of improper assembly,as in beyond tolerances rom the get-go which is absolutely on the builder.I`ve had this happen.The bearings were .02 beyond.The guy took just a tad too much off and should have gone one more size under.

as soon as I can, I have to get some oil to put back in there before i take the old stuff out, probably Monday or Tuesday, I'll probably take the truck in for a professional second opinion Tuesday. I wish it was something simple, but it doesn't look to be. the truck may have to sit until I get enough money to work on it.

[highperf4x4]

That's a bummer. Any chance of getting the builder to warranty the motor?

[americanmusc1e]

Originally Posted by highperf4x4

That's a bummer. Any chance of getting the builder to warranty the motor?

I doubt it.

[brad_man_72]

you're going to drive a knocking truck!!!!

[highperf4x4]

Originally Posted by brad_man_72

you're going to drive a knocking truck!!!!

I'll second that, you could ruin a head, crank, block etc if you drive it.

[americanmusc1e]

Originally Posted by brad_man_72

you're going to drive a knocking truck!!!!

I might would consider driving a knocking truck. but not one with low oil pressure.

this is OK I guess. I hope the bore is OK cause its already .060 over. This is the excuse I need to convert to a 383 stroker with forged pistons. but I'll have to sell my 4-wheeler to fund it

[americanmusc1e]

Anybody want to make an offer on a '03 Honda Recon ES

here's the 4-wheeler and some of my truck

YouTube - Doughnuts etc..

[americanmusc1e]

I shouldn't have put that on there, nobody's gonna want to buy it the way I drive it

[piecesparts]

I haven't taken the time to check each entry to this forum, but definitely pull the fuel pump and check the arm that runs it from the cam. If that has a lot of slop it will sound like a rod knocking and only does it under load.

[truckdude239]

new motor oil is suppose to be changed at 500 miles then at 1500 mile and every 3,000 mile after. on a new motor it is best to go easy on the motor for the first 3k miles of its life

[faribran]

I shouldn't have put that on there, nobody's gonna want to buy it the way I drive it
BINGO

[special-K]

You only have to drain a little oil to test.You can always pour it back in.If there`s metal,you won`t be driving it anyway.If there`s none you just pour it back in.and,still shouldn`t drive it.The machining i`m talking about is on the crank and the bearings are sized acordingly.A builder could have lubbeb up on that and it woukd absolutely be his responsibilty.There would be no metal from damage,just beyond tolerance.
You say you cahnge it every 3,000 miles.How many 3,000s are in 4,000?That`s after a motor is broken in.You didn`t run it past 500 w/o changing your break-in oil did you?The next oil change should be at anither 1,000.then,go on the routine.
It sounds like you think you need to thin 20w-50.Not at all.20w is very thin.That`s what multi-grade means.It`s 20w and everything between 50w,depending on motor`s needs and environmental changes.We used to run one weight in the cold months and go to thicker oil in warmer weather.Now you don`t have to think about it.
If you ran the snot out of it rather than breaking it in along with running too long on thinned out oil I`d say you bought yourself an expensive lesson.

[RustyParts]

I had a rocker arm stud that was worn on one side letting the rocker arm slide off the pushrod. The engine would idle but when I revved it up it would knock and loose oil pressure because the lifter was trying to come out of the hole. Easy to check out by removing the valve covers.

[americanmusc1e]

Originally Posted by special-K

You only have to drain a little oil to test.You can always pour it back in.If there`s metal,you won`t be driving it anyway.If there`s none you just pour it back in.and,still shouldn`t drive it.The machining i`m talking about is on the crank and the bearings are sized acordingly.A builder could have lubbeb up on that and it woukd absolutely be his responsibilty.There would be no metal from damage,just beyond tolerance.
You say you cahnge it every 3,000 miles.How many 3,000s are in 4,000?That`s after a motor is broken in.You didn`t run it past 500 w/o changing your break-in oil did you?The next oil change should be at anither 1,000.then,go on the routine.
It sounds like you think you need to thin 20w-50.Not at all.20w is very thin.That`s what multi-grade means.It`s 20w and everything between 50w,depending on motor`s needs and environmental changes.We used to run one weight in the cold months and go to thicker oil in warmer weather.Now you don`t have to think about it.
If you ran the snot out of it rather than breaking it in along with running too long on thinned out oil I`d say you bought yourself an expensive lesson.

changed the oil at a little less than 500 then again 2500 miles later when my odometer was at 6000. right now my odometer has about 7500 miles on it

[americanmusc1e]

Originally Posted by RustyParts

I had a rocker arm stud that was worn on one side letting the rocker arm slide off the pushrod. The engine would idle but when I revved it up it would knock and loose oil pressure because the lifter was trying to come out of the hole. Easy to check out by removing the valve covers.

I've been having all kinds of rocker arm problems, I guess I should check that

[special-K]

It could be alot of things.But low oil pressure points away from most.Was the oil pump replaced?
I based my other remarks on the 4,000 mile statement.i guess it`s been knocking for awhile?
I wish I could check it out.I hope it`s not too serious.

[highperf4x4]

Actually break-in oil should be changed immediately after the first 25 minutes of breaking in the camshaft. You make sure your lifters are properly adjusted, start the engine (without excessive cranking) immediately bring the engine up to 3000 rpm and then vary the rpms between 2500 - 3000. This causes the crank to throw oil on different areas of the cam. Immediately after the camshaft break-in, you change the oil, change it again at 500 (when rings have seated) and after that, every 2000 - 4000 miles depending on your driving style.

I will say this right now, your problem was not caused by not changing the oil. It could be that the cam was not properly broken -in and the metal shavings are chewing up your mains/rods or like previously stated, the crankshaft was not properly ground or bearings not matched.

I'm getting the distinct feeling that this was not a "new" build??????

Are we talking about all new parts here and fresh machine work? Did you pull used crank and cam from another motor and just throw some new bearings on it? If it's a used cam, did you match the lifters back to the exact same lobes they came off of?