Engine Block Oxidation

[DMC3165]

Hi all. Over time I've noticed a gradual discoloring of my engine block that is clearly oxidation. I spoke to Grady about it around a year ago and he said not to worry about it. Having said that asthetically I think it just looks like crap. So I'd like to do something about it. I've been contemplating the idea of washing the engine with industrial aluminum wash which is a light acid. The only drawback is it slightly opens up the metal but at the same time will instantly stop all oxidation. A few others had recommended painting the engine but that is more of a project then I'd like to get involved in. If the engine has to come out of the car for any reason I may consider doing something like that or powder coating. But for now I'd like to clean it up so it just looks a little better.

Thoughts?????

[Bitsyncmaster]

Aluminum will oxidize. So even if you do the acid wash.....you will need to clear coat it to keep it that way.

[Delorean Industries]

the oxidation will return if you only wash with an acid. Plus the type you use matters. The only way to properly clean up the finish and remove the oxidation is to blast the surface with 50 grit aluminum oxide followed by soaking the block in a solution that costs 455.00 for five gallons and must be heated to 180 F. Once removed hit with a matching base soap and dried with a clean air supply. IE filtered and inter-cooled compressor air with multiple mineral traps for compressor oil contamination. Followed by one hour in a clean oven at 350 F. Repeat the first steps and bake again if an impurities leech out.

I have spent years trying to prep blocks and this is the only way. Everything else is a half measure that will not hold up to the environment. This is why you see POR 15 disasters on Deloreans. Your level of prep decides your final finish.

[DMC5180]

Josh,

What is you're preferred Final finish for a block? Have you ever Clear coated one or a whole engine package?

[Delorean Industries]

Josh,

What is you're preferred Final finish for a block? Have you ever Clear coated one or a whole engine package?

Yes and the finish does not last. When you use engine enamel high temp clear the finish will brown over time. The only clear that will hold up is powder coating. I finish blocks with a GM prep engine enamel I have access to that matches are company powder coat package option. Once applied to the block the finish is baked for an hour prior to assembly of the engine.

[DMC5180]

Yes and the finish does not last. When you use engine enamel high temp clear the finish will brown over time. The only clear that will hold up is powder coating. I finish blocks with a GM prep engine enamel I have access to that matches are company powder coat package option. Once applied to the block the finish is baked for an hour prior to assembly of the engine.

The FEW photos I've seen of your Builds appear to be Silver Finish VS. Clear. Have you done a whole engine in Clear powder coat? If so do you have any photos?

Thanks

[Delorean Industries]

I will need to look. It has been at least two years since one like that. If I remember correctly the aluminum was blasted with black oxide, then walnut shells to add a polished finish and coated.

[DMC5180]

I will need to look. It has been at least two years since one like that. If I remember correctly the aluminum was blasted with black oxide, then walnut shells to add a polished finish and coated.

Was it customer requested or something you just wanted to try?

[Delorean Industries]

Was it customer requested or something you just wanted to try?

I tried it initially after seeing a car that Tony refinished by blasting all of the covers and coating with enamel. I knew the millage from service records when the work was performed and did not like how far gone the finish was. This prompted doing a few test pieces on one of my cars that at this time resides in vegas I believe.

[David T]

Getting back to the OP's original question, one way is to use Gunk engine cleaner and spray the motor with it and hose it off. Brushing to remove the heavy deposits of of dirt, grease, and oil. It won't stay clean though, especially if you have any leaks. All of these other more through ways require removal and dis-assembly. You are not going to powder coat an assembled motor and then bake it to cure the powder!
David Teitelbaum

[DMC3165]

Thanks for the replies. As long as no one thinks there would be any negative affects by washing the engine with gunk and aluminum acid I will most likely just do that for now. Later on if I pull the motor for any reason and and get involved in a major project I will have it done professionally. Either powder coating or painting. Really I just want whats there cleaned up so it looks a little better for now.

[DMC5180]

The only thing I would worry about is getting the that combination of liquids trapped in the VOD wells. Aluminum acid wash is ACID. It will eat away the Oxide layers and metal if not completely flushed out and dried. I use a product at work called Alumi-prep 33. It removes the oxide layer prior to dipping the aluminum in (Alodine). We only let the Aluminum parts sit in the (acid) for 3 minutes. I accidently left a small piece of aluminum sit in the acid bath overnight once. It completely ruined the piece. (Turned it Black)

Having liquid pools of acid sitting in the VOD wells would not be good. This is assuming you don't pull the Intake to gain access to the VOD and dry things out.

[David T]

I would not recommend washing the top of the motor for several reasons including filling the area under the intake manifold (the VOD or Valley of death). If you get ANY water into the spark plug wells the motor won't run. You can also get water in the distributor. Have fun on the sides and back, just don't wash the top. In fact, this is excellent advice so you can find leaks. You have to remove the dirt and oil and watch where you first start to see exactly where the fluids start to leak from so you can identify the area that is leaking so you know what to take apart to fix. Cleaning the transaxle is a lot harder because of all of the external ribbing. A couple of old toothbrushes can help. Make sure to thoroughly rinse off ALL of the Gunk. This can be messy, you might want to take the car to a shop that can steam clean the motor for you.
David Teitelbaum

[Bill Robertson's Sock Puppet]

I would not recommend washing the top of the motor for several reasons including filling the area under the intake manifold (the VOD or Valley of death). If you get ANY water into the spark plug wells the motor won't run. You can also get water in the distributor. Have fun on the sides and back, just don't wash the top.

I know an owner who floods his intake valley with the hose every single time he washes his car with no negative effects whatsoever (he's been doing this for nearly a decade). As a result the area under his intake manifold is very clean with no accumulated dirt or debris whatsoever, despite his car traveling nearly 10,000 miles annually. All he does is stick the hose under the intake manifold and let it run for several minutes. There is a raised area in the back of the engine, so all the water and anything washed out runs harmlessly on either side of the water pump.

[David T]

Just because someone does this and "gets away" with it is no good reason to recommend it. There have been many posts about someone who just washed the car and some water got on top of the motor and now the motor runs like cr-p. I knew about another person who washed his lawnmower every time he cut his grass. The underside of the deck was very clean and rusted through. It is not necessary to clean the top of the motor all that well and certainly not often. There are cavities that will hold water and when they rot out you will see oil gushing out!
David Teitelbaum

[Delorean Industries]

That really isn't good advice. Owners should stick to listening to professional advice on here. Cleaning the valley is extremely important.

[Bill Robertson's Sock Puppet]

Just because someone does this and "gets away" with it is no good reason to recommend it. There have been many posts about someone who just washed the car and some water got on top of the motor and now the motor runs like cr-p. I knew about another person who washed his lawnmower every time he cut his grass. The underside of the deck was very clean and rusted through. It is not necessary to clean the top of the motor all that well and certainly not often. There are cavities that will hold water and when they rot out you will see oil gushing out!
David Teitelbaum

First time I ever heard anyone blame block rot on water....

You have admitted that you only drive your DeLorean 500 miles per year (insurance restriction -- ever thought about simply disconnecting your angle drive to get a little more road time?), yet you argue against owners who drive 10,000 miles per year?

Water boils at 212 degrees. Simply getting the engine up to temp will boil any water anywhere on the block right off (same principle works on condensed water in the oil BTW).

The intake valley is nowhere near the spark plugs. A big piece of aluminum (the intake manifold) stands between them. And the spark plug wells are protected by water tight boots, unless the owner has worn out boots, or they aren't seated properly.

[Michael]

just a few weeks ago detailed my engine to the nines which included cleaning my VOD. I did use degreaser and aluminium wheel cleaner and I did of course have to use water. There was a lot of water left standing in the valley. I used a shop vac with a specialy made rolled fitting to get 95% of the water out. I then started the engine and let it idle for about 20 minutes, then took it out for a spin. Like David said the engine missed a little under load and I knew I had got a bit of water in one or more plug boots. I thought I took as much precaution as I could but in the end heat and evaporation did it's thing and after sitting hot for about an hour it ran perfect. I would most definately do it again....Although I have cleaned and detailed the engine many times, that's the first time in 3" years I have cleaned the VOD so it's not like it needs it often.

Yeah it's a lot of work keeping a car detailed to the max, but it's rewarding not only because I like cleaning it, but I like showing it off. You don't get to look at my car without me insisting you lie face down and checking out the undercarraige.:smile:

[refugeefromcalif]

You don't get to look at my car without me insisting you lie face down and checking out the undercarraige.:smile:

Face down? Wouldn't that put the person staring at the ground? :confused:

(Sorry, I had too)... :biggrin:

It's about time for me to do a good engine cleaning so, I'm making notes of the ideas here.

George

[David T]

Over time dirt, dried coolant, grease, and oil gets on top of the motor. It collects in the cavities on the top of the motor and becomes acidic when wet and attacks the aluminum. Once it rots into the motor it allows the oil galleries to pump oil out of the top of the motor. I agree it should be cleaned, I just can't endorse "sticking a hose" on top of the motor. When doing service work on the top of the motor (like replacing the water pump) it is a good opportunity to clean things up. BTW, you have to get the motor really hot for a while to boil all of the water that can collect in those cavities. There are wires and electrical connections that can corrode in that area so flooding it with water is not a great idea. It can also cause the steel bolts to rust in the aluminum so when you go to take things apart they break. I don't expect to change your mind, I am just expressing my opinion on this method of "cleaning" a motor. Besides, anyone trying to keep areas of the motor clean that you can't even see is IMHO overdoing things.
David Teitelbaum

[cdrusn]

Over time dirt, dried coolant, grease, and oil gets on top of the motor. It collects in the cavities on the top of the motor and becomes acidic when wet and attacks the aluminum. Once it rots into the motor it allows the oil galleries to pump oil out of the top of the motor. I agree it should be cleaned, I just can't endorse "sticking a hose" on top of the motor. When doing service work on the top of the motor (like replacing the water pump) it is a good opportunity to clean things up. BTW, you have to get the motor really hot for a while to boil all of the water that can collect in those cavities. There are wires and electrical connections that can corrode in that area so flooding it with water is not a great idea. It can also cause the steel bolts to rust in the aluminum so when you go to take things apart they break. I don't expect to change your mind, I am just expressing my opinion on this method of "cleaning" a motor. Besides, anyone trying to keep areas of the motor clean that you can't even see is IMHO overdoing things.
David Teitelbaum

I wasn't going to chime in but your chemistry demands some kind of reasoning. The difference between being acidic and alkaline depends on their Ph. acid being 0-6 and alkaline being 8-14 (7 is neutral). Water of course is alkaline the amount of Ph depending on the minerals suspended. It would be impossible to add water to dirt, dried coolant, grease and oil and make them acidic. Usually what water does is act to create an electrical discharge from one material to the other, usually from aluminum to steel thus creating holes in your engine around a steel bolt. The water itself won't attack the aluminum but when combined with another metal source could then act as a catalyst to create an electricrolysis that might attack the aluminum. Anyone with an engine that has a steel block and aluminum heads who hasn't changed out their coolant when required and who doesn't use steam distilled water in the mix will find out that the resulting old coolant will definitely eat a hole in the head anywhere there is a steel seat or bolt. If someone wants to power wash their engine be my guest but more than being worried about some kind of acid attack I would recommend having a good air compressor and blow attachment to blow the water out of all the nooks and crannies so it doesn't interfere with electrical connections. Make sure you cover the distributor, alternator, coil area, and any other electrical connections you can. JMO

[Bill Robertson's Sock Puppet]

The process of which you speak is variously known as galvanic corrosion or electrolysis (electrolytic corrosion). It is indeed a very real threat between aluminum and steel -- ask any DeLorean owner who has tried to remove steel fasteners from his coolant system, such as the Y pipe hold down bolts -- but it does not happen instantaneously. And there is no steel in any of the casting recesses anyway -- only aluminum.

IMHO block rot is caused by impurities in the original casting, the design of which is too thin to begin with. Veteran DeLorean mechanics have seen block rot even on engines that are meticulously maintained. Note that block rot does not have to be the death knell of an engine -- I personally know two owners who have been living with it for years (they effect a repair which lasts for a while, then effect it again when that repair eventually fails. There does not seem to be a one time forever cure -- it's kind of like living with a recurring illness).

[David T]

Without getting into the chemistry or figuring out if the problem is acidic or basic, we can all agree that the bottom of the cavities on the top of the block can "rot". I don't think flushing the top of the motor regularly with water is the way to prevent this. Periodic maintenance and cleaning can. It would be helpful if we knew the exact chain-of-events that cause "block rot" so we can do more to prevent it. I suspect it has a lot to do with the local chemistry of the water and if the car is stored outside in the rain.
David Teitelbaum

[Delorean Industries]

Volvo knew there was a problem present. The block casting was quickly changed in august of 84. Late model engines do not have this issue. This is why we now have liners that fit a 3.0 block but with a 91mm bore. Superior block by far purely based on casting techniques.

[DMC5180]

Volvo knew there was a problem present. The block casting was quickly changed in august of 84. Late model engines do not have this issue. This is why we now have liners that fit a 3.0 block but with a 91mm bore. Superior block by far purely based on casting techniques.

Interesting: What does the VOD area of a 3.0 block look like?

[LEVY]

Without getting into the chemistry or figuring out if the problem is acidic or basic, we can all agree that the bottom of the cavities on the top of the block can "rot". I don't think flushing the top of the motor regularly with water is the way to prevent this. Periodic maintenance and cleaning can. It would be helpful if we knew the exact chain-of-events that cause "block rot" so we can do more to prevent it. I suspect it has a lot to do with the local chemistry of the water and if the car is stored outside in the rain.
David Teitelbaum

David,

You nail it!

Distilled water (as well as rain water) is very aggressive. Cleaning the engine with tap water should not do much damage. Distilled water is "out of balance" and it is constantly looking for minerals to dissolve, if nothing else, water will take minerals from your block, radiator etc.


LEVY

[Delorean Industries]

Same appearance different metal composition.

[Bill Robertson's Sock Puppet]

Distilled water (as well as rain water) is very aggressive. Cleaning the engine with tap water should not do much damage. Distilled water is "out of balance" and it is constantly looking for minerals to dissolve, if nothing else, water will take minerals from your block, radiator etc.

Who in the world washes his car with distilled water?

[LEVY]

Who in the world washes his car with distilled water?


Why don't you read, read, and read again, maybe you get it this time.

By the way, half a gallon of distilled water on the final rinse will produce a spot free car!

LEVY

[Bill Robertson's Sock Puppet]

Fair enough: who in the world washes his engine with distilled water? (I thought we were still talking about flooding the intake valley with a hose while washing the car).

[LEVY]

Fair enough: who in the world washes his engine with distilled water? (I thought we were still talking about flooding the intake valley with a hose while washing the car).

Still don't get it?

Go back and read again, from the last post from David.

Seems like some people need to go back to school!

LEVY

[Bill Robertson's Sock Puppet]

You are the one who interjected distilled water into the discussion. Why not say "washing the engine with tap water is OK, but don't do it with grape juice" -- equally preposterous.

David is against flushing out the intake valley period, no matter what is used -- tap water, distilled water, grape juice, whatever.

[LEVY]

You are the one who interjected distilled water into the discussion. Why not say "washing the engine with tap water is OK, but don't do it with grape juice" -- equally preposterous.

David is against flushing out the intake valley period, no matter what is used -- tap water, distilled water, grape juice, whatever.

You still don't get it!

Read my answer to David's post!

This time read it 100 times before you post again, if still don't get it, well, I don''t know what to tell you.

Since seems like you will never get it without help, let me give you a clue:

I posted: David, you nail it! (you nailed it, but auto-correct-ed)

LEVY

[Jeremy Popp]

But for now I'd like to clean it up so it just looks a little better. Thoughts?????

I ran into a guy at a DCS years ago, and I asked how he kept his valve covers so clean looking. He replied that he uses WD-40. It LOOKS clean and nice, and you can't see the oxidation. Maybe someone can confirm if there are any negetive effects longterm?

[Patrick C]

Carb cleaner and a green scotch brite pad really clean up the bare aluminum valve covers well. A concours DeLorean owner showed me this trick.

[David T]

Be careful with stuff that is flammable and you should avoid the use of anything containing silicone near the motor (it can get into the intake and contaminate the O2 sensor). Using carb cleaner you should take common sense precautions and wear personal safety protection (gloves, safety glasses, respirator). WD-40 won't clean anything but it will help to prevent it from oxidizing once it is clean.
David Teitelbaum

[Bill Robertson's Sock Puppet]

Carb cleaner is extremely evaporative. Within 60 seconds of spraying it on, it is gone. Unless you're smoking while cleaning your engine, nothing is going to catch fire.

[David T]

Carb cleaner is extremely evaporative. Within 60 seconds of spraying it on, it is gone. Unless you're smoking while cleaning your engine, nothing is going to catch fire.


Then I guess you know you should not be spraying it on a hot motor or while it is running! Before it so quickly evaporates it it can flash into flame! There can also be small pools of it for a few minutes in areas where it collect so it can take more than a minute for it all to evaporate and dissipate.
David Teitelbaum

[Bill Robertson's Sock Puppet]

If you are scrubbing your engine with a green Scotchbrite pad then I too hope it isn't running at the time -- feels really bad when your fingers get caught in the spinning belts.