Short block cleanup before assembly

[vjquan]

Wanted to get some opinions here. I have a Nissan V6 motor out. I took the heads off and got a valve job done. I'm not planning on rebuilding the short block, but would like to clean it up a bit of the varnish and other buildup. How do you guys recommend I do this? Pull the oil pan and spray it down with degreaser and hose away? What about the block head surface? Maybe just leave it alone and just prep the head surface?? What are your opinions/suggestions? Thanks.

 

[dcovey]

Are you talking about cleaning the outside or the inside as well?

I would be careful cleaning the inside without complete disassembly. I have had oil pumps "lock up" because of broken valve stem seals or plastic timing gear material was sucked up in it. I guess what I'm saying is unless you are sure you removed all the loose stuff it could happen.

Clean the parts you take off (pan, timing cover, head, etc.) those you can see what you are doing with.

If it's just the outside. Tape all the openings up real good and spray some gunk on it and take off to the car was unless you have your own pressure washer. Even a hose and a brush will help..

JMO

Dave

 

[tcianci]

What he said, otherwise you could end up with a short block ready for rebuilding...atleast it will be clean.

 

[muncie21]

When I changed the head gaskets on my Chevy 350, I scraped the hard sludge with a putty knife and put it in a bag. Afterwards, I sprayed the block down with degreaser and went to town with a wire brush. Drained the oil before firing up the engine and drain it again (changing the filter too) after letting it get up to temp and run for 5-10 minutes.

Be sure you don't use abrasive products (green scouring pads, steel wool, etc.) to clean things up, as they won't do your bearings any favors if they get lodged in the engine.

 

[jgoglick]

Nothing you can do without disassembly. Carefully clean the surface of the block so you have a good surface for the heads to sit on. Preparation is your friend here - blocking holes so gunk doesn't get in. You could pull off the oil pan and have a look at the bottom end, but that quickly gets into a case of the "while I'm at it" syndrome, and before long you are rebuilding the entire engine.

 

[tcianci]

Remember that the temptation to put bearings in it if you have the pan off can come back and bite you. If the engine has any real miles on it there is a wear pattern in the cylinder as a result of the ring travel that creates a ridge at the top of the cylinder. While it is probably minute, the new bearings will result in the piston moving just minutely higher in the cylinder because they have more metal to them than the ones you took out. In some cases this can result in broken top compression rings or cracked ring lands on the piston. What you're working on as a classic example of where less is more.

 

[spartyon8]

I did this years ago when I had my Elky. I taped every opening into the engine, soaked the engine with simple green, scrub brush, more simple green, scrub brush, then rinse. pat dry then paint. It worked for me but you need to make sure you tape every opening shut so no crud gets in.

 

[wineslob]

Diesel fuel works like a champ, and it's water soluble.

 

[gjz30075]

Sounds like the heads are off and the pan is not, correct? If so, cover the machined area of the block where the heads bolt on, with duct tape to keep anything from going down into the holes. Leave the pan on and clean the whole thing with something like Gunk, using a small brush. Wear gloves. Then gently hose it off. Don't get water near the head area.

 

[W_A_Watson_II]

Diesel fuel works like a champ, and it's water soluble.

There may be a small amount of water that Diesel will absorb, but Diesel is an oil, and oil and water don't mix. Water settles in Diesel, otherwise my diesel filter water drain would not be working.

 

[evintho]

I've done this a dozen times. It's called 'seal-n-shine'. If the motor is out, there's no better time to do it!
I assume the motor is on a stand. Lots of rags and duct tape in and on the cylinders. A little moisture won't hurt, just don't fill 'em up with water! Remove all freeze plugs then use a high pressure nozzle on a garden hose to flush out all the rust and accumulated crud from the water jackets. Remove any peripherals from the motor and Gunk the shortblock followed by SimpleGreen then plain old soap and water. Now you have a clean surface for paint. Wouldn't hurt to bottom tap all bolt holes too.
Replace the freeze plugs. Drop the oil pan. Replace the gasket and front and rear seals. Go over the cylinder deck surface with a sanding block and 80 grit sandpaper to clean it up. Now, remove the rags and duct tape from the cylinders and clean them with paper towels until the paper towel remains white. Wipe down the cylinders with 30wt oil. I agree with the other posters. Don't bother pulling rod and main caps to check bearings. Unless there's a bunch of metal shavings in the pan, it's best to leave Pandora's Box unopened! Inspect all peripherals and replace as necessary. Timing belt, idler pulleys, water pump, thermostat, motor mounts, etc.
You won't have the motor out of the car again so now is the time to fix it all! Car will probably be good for another 100k!

 

[jeepnut24]

Any other tips/tricks? Ive got an LS motor I need to do the same thing with.

 

[W-Cummins]

Remember that the temptation to put bearings in it if you have the pan off can come back and bite you. If the engine has any real miles on it there is a wear pattern in the cylinder as a result of the ring travel that creates a ridge at the top of the cylinder. While it is probably minute, the new bearings will result in the piston moving just minutely higher in the cylinder because they have more metal to them than the ones you took out. In some cases this can result in broken top compression rings or cracked ring lands on the piston. What you're working on as a classic example of where less is more.

This is not possible. IF the clearance in the rod is worn out ie. bigger ,the piston will move MORE ( higher in the bore) not less


William

 

[JPRACING]

I would take the whole engine apart and get the block hot tanked and then honed, polish the mains and journals,new bearings, cam bearing and lifters,new oil pump,clean pistons,check wrist pins add new rings and rod bearings and sleep good at night knowing the job was done the right way just my 2 cents

 

[Yoke]

Guys I don't mean to hijack the thread but I thought it would be better to ask this question here than in another separate thread. I just had a set of heads hot tanked, do I need to get the seats machined or can I just lap the valves and be done with it?

 

[JPRACING]

Just lap them in and check how they are seating

 

[muncie21]

For the guy cleaning up the LS engine, be sure to get ALL the water out of the head bolt holes. These are blind holes and you will hydrolock the bolts when installing the heads if there's water in the holes, which in turn could lead to a cracked block and a very bad day.

 

[barney rubble]

I have done this many times. Sometimes I dont even remove the heads. Pull a motor pop the intake and all the cover, valve, timing, and oil pan. Wash the motor down with carb cleaner, parts washer, lacquer thinner in a old paint gun, or what ever I have around at the time that cuts grease. Install new valve seals, rear main seal, maybe a timing chain set or oil pump and reassemble with new gaskets and a freah paint job. If the motor had no blow by and held decent oil pressure before you can get a lot of miles out of them when done. And I have at times installed new bearings and never had a problem.

I wont tell you what my buddy at the machine shop calls it. It would probably piss of some people on here.

 

[vjquan]

Go over the cylinder deck surface with a sanding block and 80 grit sandpaper to clean it up. Now, remove the rags and duct tape from the cylinders and clean them with paper towels until the paper towel remains white.

How do you sand the deck without getting all the crud into the holes? Do I need to plug the holes with something?

I plan on pulling the pan. Once it's off, do you guys see any harm gunking down the crank/rods and hosing it down or should I just leave it alone?

 

[evintho]

How do you sand the deck without getting all the crud into the holes? Do I need to plug the holes with something?

I plan on pulling the pan. Once it's off, do you guys see any harm gunking down the crank/rods and hosing it down or should I just leave it alone?

The holes are only bolt holes and water jackets. Flush out the water jackets after cleaning up the deck. Blow out the bolt holes with compressed air. No hosing down! You definitely don't want to introduce water into the engine internals! Do like I said. Pull the pan, replace gasket and seals and button it back up.

 

[JamieK]

Depending on the engine, some of those holes will be oil supply and drainback. So do not get any crud into those. Plug them up with a cork or golf tee.

BTW, the 3M scothbrite pads for a die grinder work really well, but the Roloc Bristle Discs work even better. Less chance of scoring the surface.

If you wanted, after pulling the oil pan, hose it down with a few cans of brake cleaner. Any residue will evaporate.

 

[pmohr]

Just curious, which Nissan V6? VQ, VG, VE?

 

[vjquan]

If you wanted, after pulling the oil pan, hose it down with a few cans of brake cleaner. Any residue will evaporate.

Good tip, thanks.

Just curious, which Nissan V6? VQ, VG, VE?

VG30 from a Hardbody Truck