i bought a 300zx and the guy said that the engine is "locked up" when i try to start it, it makes a loud grumbling noise. i see that the timing belt has been changed.

 

1.) remove engine.

2.)find replacement.

3.)install replacement.



what do you mean by "locked up"? will it spin at all? what do you mean by "grumbling noise"? we will need more info to help.

 

Unless it was a bad felony, I would post bail and see if you can get the engine released....or I would find a locksmith and see if they (he/she) could un-lock the engine. My friend had an engine that "froze up" my mom told him to throw some hot water on it.

 

Does it turn over? Is it locked up from water? etc

 

 

yea it turns but when i try to start it, it is really loud and the whole car shakes it sounds like its having a hard time turning.

 

does it have oil in it?

 

LOL

Drain the oil and see if you get silver flakes in it...or if you get big pieces, then it's the bottom end... hope this helps...

Year,... NA, turbo???

 

yea it has oil. ill try to drain the oil today and see if it has the flakes.

 

when i turn the engine with a ranch it turns but then at a certain point i cant turn it no longer it gets stuck and when i turn it the other way it turns again but then also gets stuck after a while.

 

That means it has compression. Take the spark plugs out.

 

lol! ^^^^ oh you... you sound like you need to do research. take teh plugs out yes. it will still be a little tough with the cam and springs. but still. what are you rotating it with? and where?

 

i rotated the crank shaft with a ratchet

 

its not that its hard to turn it, it gets stuck that you cant turn it no more.

 

seriously, take the plugs out. if it still is hard ot turn then its a major problem. the best way to narrow down is take the timing belt off and try spinning each cam and the crank separately. the stiff one is the problem.
and "ranch"? is that a thick accent coming through in your typing?

 

How exactly would having the plugs removed make it easier to turn it over manually? You really shouldn't rotate the cams separate for the crank. It could cause the valves to hit the pistons; which is bad. If the engine is binding up when you turn it over manually, then there are some major problems.

 

valve hitting piston, broken connecting rod, just some of the more drastic reasons. CHECK OIL FOR METAL PIECES FIRST!!!!!

 

Having an open hole in the combustion chamber will allow air to escape each cylinder as the piston moves up the piston chamber...I.E. less resistance when turning by hand. If the rotating assembly will only go so far in either direction with the plugs out then it is a safe bet that something is broken...could be a broken and jammed timing chain (take off valve cover and see if the chain is still in one piece) Could be a broken valve stuck in one of the combustion chambers. Could be a busted connecting rod. The car could be in gear. The starter might be jammed.

 

belt. not chain.

 

I am way to used to posting in the 280ZX area....belt huh...ok so scrap that idea

 

taking out the spark plugs just makes it easier to turn. but it still gets stuck in the same places as before

 

If the motor can turn about 3/4 of a turn, then most likely the piston is hitting the valve... if it only turns 1/8 or so, then most likely it's a bearing or the timing belt it out of time... time to take it a part... take the belt cover off and look of the timing marks and look for a part of the belt missing... Good Luck

One more thing... look at the plugs... see if one or more of the plugs has damage to the tip...

 

its turns about 3/4, i have the timing belt cover off every thing looks good their.

 

Sounds like the piston is hitting the valve... if the valve is bent, it will not close all the way, then the piston comes up to the top and hits the valve, that's why the motor wont turn 360%... now you have to find out what side...

 

What I said,

in more simple terms...

No spark plugs = no compression. No compression = no sealed chamber of air to compress. No sealed chamber of air to compress = easier to turn.

Whew!

I take it you've never done this before???