I pulled my 427 this weekend and began the tear down. I am sure I will post a few findings/questions as I proceed.

There is a fair amount of rust/scale in the cooling chamber (viewed through waterpump openings and the coolant is somewhat rust colored. Is there anything that I should do whil it is torn down or just wait to flush it upon reassembly?

The engine does not have many miles on it since the PO's rebuild and I hope to not require a trip to the machine shop. I guess I wont know for sure until I get it fully torn apart.

Thanks for your assistance

 

With that much rust in the block, I'd recommend that you use radiator Cleaner to get all the gunk out and clean off the metal surfaces. You can buy it at any auto parts store...it usually sits with the radiator "flush" items. Follow directions. When cleaned out, ALWAYS put some antifreeze in your system..even if you live in the desert. There are rust inhibitors in the antifreeze AND it will cool better than water alone {wetting agents for better heat transfer}.

 

If it's that much rust it would be a good idea to change the frost plugs. Especially if they a steel ones.

 

I change my freeze plugs to brass on all my engines, if the eng is to be removed.

 

When I finally went to the trouble to remove the spark plug wire shields to access the water drain bolts in my original owner 68 SB I used a pan to catch the water draining from each side. (engine still in car) I was surprised to find so much "stuff" in the drain water. Years prior the coolant was always changed every two years and would flush with clean water before adding new anti-freeze. This stuff in the block always remained. Many years ago bought a 63 SS in 1967 in San Diego. Although it does not get real cold there, did see it snow one December day in 1967, a heater is used. My 63's heater just was not putting out any heat. Removed the heater hoses and found the heater completely compacted with reddish looking stuff. Flushed it out easily and the heater worked fine.

 

Or you can take the block to a shop and have it acid dipped.

 

I started using 100% ethylene glycol in my 1968 SB in 1974. When I removed the engine in 2003, to replace it with a ZZ4, I looked at the block water passages. No rust, only a slightly powdery white coating left by the silicate that is added to antifreeze. I still have my original heater core in the car. My initial motive for pure antifreeze was to protect the expensive Harrison aluminum radiator that was stock for the 350/327 small block.



Since pure ethylene glycol (green stuff antifreeze) boils at 387 degrees F, another advantage is that the cooling system is not pressurized. Hoses don't blow off and you can open the cooling system filler cap at any time, even with a hot engine and not have to worry about spewing.

You can't use pure antifreeze if your car has a marginal cooling system. My 68 never overheated with pure antifreeze. I use pure antifreeze in my daily driver, a 97 Tbird, and it also does not overheat.

 

How far are you tearing it down?

 

All the way.

There was a funny noise (maybe piston slap) and some vibration on acceleration, so I decided to tear it down and check the bearings and all components. Also, I was told this was an L-88 (block and heads do match) and I was afraid to make a new cam decision without first verfiying what pistons are in there and figuring the actual compression ratio.

 

I'm with Weimer - if you are tearing it all the way down I would go ahead and take the block to a machine shop and have them hot tank it. If you do this, make sure you take all the fittings off the block (like oil pressure sender, etc), knock all of the freeze plugs out, take out all the oil galley plugs - everything - and that bath it will get will give it a real good cleansing - then have the machine shop mic up everything - they will tell you if something is out of spec or not.

If you are leaving the block in the car, then you might want to get a pressure washer and shove it in the water pump holes and see how much crap you can blow out that way.

As for that radiator cleaner and flush you get at the Zone, IMO it's a waste on money. A few years ago, the oil cooler seals on my 944 Porsche motor blew out and filled the coolant system with engine oil. I went thru 6 bottles of that prestone cleaner and still to this day I have oil in the cooling system.

If you knock any freeze plugs out for cleaning, when you knock the new ones in use brass ones, and I always like to coat the lip with a little 3M yellow adhesive, just to be sure. I also use it on the water pump, fuel pump and oil pan gaskets.

You might also want to have the radiator rodded, too.

 

If you're gonna pull a motor apart & it has a questionable past ... have the machine shop clean it. Next time ... run the block cleaner chemicals thru system before you pull the motor ... that way everything is clean when you reinstall.

Due to EPA restrictions ... nowadays VERY FEW shops offer a dip in an acid / caustic VAT.

Nowadays, MOST shops use a pressure wash cabinet that's not so unlike your home dishwasher ... but its liquid's strength is NOTHING like what was once pre-EPA standard.

Nowadays, MANY shops also use a "bake & blast" process whereby the block is baked at high temp & blasted with very small media. Believe me, this process works REALLY well ... if done right I think it's better than old-style vat. The heat dries up the old oil/sludge/tar & the rust ... it just falls away. This bake & blast should be followed by a wash in the "dishwasher" wash cabinet; most shops with bake & blast will also have a wash cabinet. Done right, you'll think you got a new block. I swear, that baby'll be really, really clean & bare! You think I'm BSing you ... but when you first fire it up, b&b'd motors often use an extra pint or 2 of oil that was lost from the pores during bakeout & wash.

 

Here is a picture

 

Pull out the 1/4" pipe plugs on each side of the block to see how bad it really is. Your pic doesn't look that bad.

Here is what I have done several times to ones that look much worse.
Pull engine out.
Set it on it back on the flywheel so the water pump faces the sky and tape up the upper and lower radiator hoses together so they are higher than the engine.
Loop the heater hose fittings together.
In the bottom rad hose, pour a 50% solution of water/muriatic acid, until it levels in both hoses.
Leave for 1/2 hour.
Knock out all the tin freeze plugs.
Flush out the loose crud with water.
Replace with all brass plugs.
Refill with mild baking soda solution to neutralize acid and flush with clean water.

Inside of cooling jackets will be as clean as the day it was made.

Before anybody balks at this process, I still have a 1 ton 350 that I did this to 12 years ago with absolutly no problems, still runs great, but I change coolant yearly.
Some of these engines you get are in such bad shape due to no maintenance that this is sometimes a good choice. If doing a very rusted engine in the vehicle, it can sometimes plug the rad.

Don't use Muriatic acid if the engine is in the vehicle and connected to the rad or heater core. Much too strong. Use the oxalic acid method.

 

Thanks for the advice. I just flipped it over and thick rust crud came out. I think that I will be ok with some kind of flush. The acid is a good idea, but I have already pulled the heads.

If I can get most of the scale out with high pressure water and some cleaning agent maybe I will be ok. I think it needs to get cleaned before I connect it back up to the radiator.

 

Noonie - muriatic acid - what a hell of an idea - I cant wait to try that one.
Now you got me thinking, what if you joined the heater hoses together and the radiator hoses together, took the thermostat out and ran the motor with the water/muriatic acid mix till the motor got warm, then let it cool down and then repeat the process a few times - i bet that would get it nice and clean inside? We have a swimming pool so I always have muriatic on hand! Thanks for the idea.

 

Don't run the muriatic thru a rad or heater core. Tried that when I was 16 and trashed both.

Only thing to consider with it in the vehicle would be the rear freeze plugs. Might start leaking on you and inaccessable.

I've done this in less than a day before; removing engine, cleaning, new plugs and reinstalling, but that was with absolutely no other sidebars. Just focused on the cooling system.