scenehouser

Hey guys,

I'm doing my first engine teardown (and hopefully my first rebuild later on) so I thought I would open my own topic where I can ask all the stupid n00b questions (:

A few weeks ago I bought a complete engine with damage. The seller told me it ran but was making a lot of noise and that it probably had bearing damage.

I soon discovered I had a real mess on my hands.

When I removed the intake manifold I found a squirrel nest so this engine has probably been sitting for a long time.



When I removed the rocker covers I discovered the whole inside of the engine is covered in a layer of burned or cooked black oil.



How bad is this? Did this happen while running or is it from sitting a long time?

As expected the lower oil pan was full of little silver en copper colored bearing chips. No pics of this.

When I removed the cams I found quite some wear marks on the cams and the heads.







Does this mean my heads and cams are goners? I was really hoping to atleast be able to salvage my heads. new cams I can live with. How come they don't use cam bearings?

Okay now it was time for the pistons and crankshaft.

The second piston from the front has a spun rod bearing that grind away at the crankshaft:





Nice

The only part that actually looks okay to my untrained eye is the cylinder block which is also the most important. There are some faint vertical lines on some of the cylinders but I wouldn't call them grooves so I think oversized pistons will be fine. But I'm not what you call an expert..

What's the best way to clean my parts? I think I read somewhere aluminium engines can't be cleaned the same way as iron blocks...

Darkknight916

i did an engine teardown about a year ago and had the block sent to a machine shop to bore it out .020" and clean it. it only cost about $300 to do so, and they let me know that that was enough to remove any cylinder wear grooves/imperfections. also they magnaflux-ed the block to makes sure it was still an adequate foundation for my build. that's about the only way that you'll be able to tell if the block is good.

as for the spun rod bearing and that wear, you can always measure it with plastigages and determine if you are able to machine down the surface so to use oversided rod bearings. all is not lost, you just have more work to do than a normal rebuild... and probably more coin to drop too. i'm interested to see what's the real deal! good luck dude!

scenehouser

i'm just back from a very respectable tuner here and he had a quick look at my block, heads, crank and cams and probably everything is salvagable so that's good news (:

now i need to figure out if a new crank will not be cheaper and easier in the long run.

johnwigs

if you paid to have your aluminum (non-ferrous) block to be magna fluxed you got had... aluminum is not magnetic... maybe the machinist did something else... dye penetrant???
and measure with plastiguage??? that is an oxymoron... pull out a micrometer and measure your ****... the sludge buildup is caused from the previous owner NEVER changing the oil... the block should be good and the heads should be good... no bearings needed for the cams... head is made of aluminum no bearing needed because it just spins and minimal stress is applied to the journal... a used good crank is easy to come by... verify straightness and replace cams... when the lobes are coated like that then the nitrate has worn off and the oil has penetrated the metal making them fragile (italian) and after block and heads are hot tanked (not acid, it will eat the aluminum) make sure your oil drains and galleys are clean and free of debris... then you will be on your way to a build-up

scenehouser

thnx john i will look into replacing the cams.

don't worry i didn't pay for anything yet.. it was just an eyeball inspection.

seems my gamble with buying this damaged engine paid off (:

Brett@AwesomeZ

Yea, it's pretty nasty when you get an engine like that. It's pretty obvious that the previous owner didn't change the oil. The heads will be o.k. those little scars can be polished out, the crank on the other hand may not work out. Best to take it to a machine shop and see if they can cut it down and set you up with some over-sized bearings.

scenehouser

Everything is getting cleaned right now in one of those big washing machines for engine parts.. after that the cylinder bores will be measured and the heads checked for straightness.

then it's time to start ordering pistons, rods, bearings etc..

i'm not sure yet if i will try the save the crank or just get a new one and don't have to worry about thicker bearings and extra machinework etc. the cost difference will probably be minimal.

the heads is also something i'm not sure about.. my goal will be 500 bhp at the crank.. can i use the stock heads for that or should i make changes to the valves and springs? the heads seem terribly complicated to me ):

Brett@AwesomeZ

If you are going to get aftermarket cams, then yes you'll want to get some stiffer valve springs, but bigger valves aren't necessary unless you are planning to make 600+ whp.

scenehouser

I would rather keep these cams if possible. Or is that a bad idea?

Brett@AwesomeZ

Can't use the ones from your current engine? If not, there are so many people getting upgraded cams that you should be able to pick up a set up stock cams super cheap.

johnwigs

500hp at crank!!! must be going FI... twins turbos must be in order... or you have money to blow... im planning on 400hp at crank NA and it is requiring a meeting of the minds to make it possible without having to spend$$$$ luckily I get alot of parts free working for nissan

scenehouser

yeah i'm going for FI (:

till what power are the stock heads useable?

johnwigs

1000hp... or really close I know 850hp... make sure you pipe clean all the oil passages!!!

scenehouser

can anyone tell me what sizes bottoming taps i need to clean out all the threads in the cylinder block?

btw what is this?

johnwigs

water pump water drain.... B4 taking off rear cover you pull that out and the waterpump drains somewhat cleaner than when the cover is taken off with the block full of water... still makes a mess

vq35sx

Best of luck on your rebuild houser. Starting today I will also be tearing apart one of these motors (also my first tear down and rebuild haha). The engine I purchased seemed to run okay when I purchased it, but the car was in a roll over so I felt an inspection was necessary.

I decided to troll some forums for information so I don't get too lost, which is how I came across this post. I wish you the best of luck, sorry I can't provide some tips to you though. Your documentation will be of assistance to me however, so thank you in advance for your help