PDA

View Full Version : Aluminum Heads, The solution !



mphatc
11-29-2007, 08:57 PM
For a while I've been researching new processes to protect aluminum cylinderheads in marine applications. I thought I'd share what I've learned, possibly other folks can add to this, or maybe this info will help someone else.
Dis-similar metals tend to increase corrosion rates. A marine engine likely has brass, bronze, cast iron in the cooling circuit, add aluminum and then run electrical power through the engine block, ie ground circuit for the starter, etc. and you have a nice solution eating away on the aluminum.
You can avoid all of this with a closed loop cooling system and antifreeze . . but that didn't work for me . .
Dart Machinery has the solution . . http://www.dartheads.com/
They have for the past 5 years been coating the internal water jackets of cylinderheads to stop corrosion. They consider it a dye solution, not a coating.
Any coating will slow heat transfer, and on the cooling side this will reduce performance. After all the primary purpose of aluminum heads to cool the combustion chamber roof for more power.
I looked at all sorts of options, from a replacable anode in the cooling system, to anodization, and numerous coatings.
All the coatings create a thermal barrier raising operating temps. I reviewed ceramic coatings, White Lighting as used on headers, and powder coating.
Anodization will not last in this environment.
The sacrificial anode seemed like a good solution, but the frequency of replacement was a concern, and they won't work on the volume that is not soaked in water, ie; while on the trailer or in storage.
Dart Coatings offers this propietary dye solution for the water jacket, and also offers a finish for the outside of the head to protect against external corrosion and oxidation.
The cylinderhead internal coating is ~$75.00 per head and this can also be done
to aluminum intake manifolds.
I elected to do ceramic coating of my aluminum intake, in the hope that it will insulate it it from engnie heat , and it is easy to clean.
So why did I chose to eliminate a closed loop cooling system which offers numerous advantages . .better thermal equilibrium to the engine, corrosion protection and freeze protection. I live in NH . .
It adds a bunch of weight, and costs more to set up, the main heat exchanger for a 400 HP SBF weighs a lot, my boat runs a Bravo drive, which has no water pump. This required two water pumps on the engine, one crank driven for cooling water and one electric pump to circulate the engine coolant, add to this an alternator, a power steering pump all on the front of the block Complex assembly in a Corsican with it's small hatches and deep engine compartment. Never mind servicing it a few years from now.
I also just added CMI SS headers. These babies aren't light, so weight became a concern as well, and they do take up alot of space which limits access.
I hope this works, the most I loose is a set of AFR heads, but that should take many years. I do plan to add a flushing set up to flush out the murky waters . . .
Please if someone can shoot holes in this, don't hesitate to share information.
So for my next boat I'll run a BMW V10 . .
Mario L.

gcarter
11-29-2007, 10:07 PM
Good luck Mario, it sounds interesting......but I'd live w/the weight.

yeller
11-29-2007, 10:07 PM
I always ran an aluminum intake and exhaust on my 16. The exhaust was on for 18yrs and the corrosion was negligible. In that time I used 3 different intakes, and when removed, none showed any signs of corrosion. I ran mostly in fresh, but still dropped it in salt 1/2 dozen times a year.
I've never bought the "aluminum is no good for marine" theory. It's all in the flushing.
Now, if the boat were stored in saltwater, maybe that'd be different.

MOP
11-29-2007, 10:33 PM
Sounds like a plan! Even a few years down the road I doubt you will notice much if any deterioration. Aluminum does fairly well in salt, I have seen know of few over the years that got surprising time on their stuff. There is an old thread that I was in on about the subject: http://www.donzi.net/forums/showthread.php?t=26331&highlight=aluminum+salt+water

Cuda
11-29-2007, 11:09 PM
I always ran an aluminum intake and exhaust on my 16. The exhaust was on for 18yrs and the corrosion was negligible. In that time I used 3 different intakes, and when removed, none showed any signs of corrosion. I ran mostly in fresh, but still dropped it in salt 1/2 dozen times a year.
I've never bought the "aluminum is no good for marine" theory. It's all in the flushing.
Now, if the boat were stored in saltwater, maybe that'd be different.
I agree the whole aluminum doesn't last in saltwater is way overblown. I pulled the thermostat housing off my Formula earlier this year, to check for corrosion in the aluminum intake. There was not a sign of it, but of course, I flush it religiously, and the boat has known use 99% of the time in salt.

Cuda
11-29-2007, 11:10 PM
Btw, what are outboards mostly made of?

gcarter
11-30-2007, 08:49 AM
Btw, what are outboards mostly made of?

But Joe, outboard innards have a very expensive coating added during manufacturing. Also they have a lot of anodic protection.

gcarter
11-30-2007, 09:01 AM
Mario, I apologise if I was a bit blunt, above. IMHO, if any of us were to buy a new car, we wouldn't even consider not having antifreeze in it, and not just for warranty reasons. Why would we build a $6K-$10K engine and do any different?????????????
If I'm wrong, screw the car warranty and just put water in it and never do any other maintenance!:smash:
Why do we take better care of our car and truck engines than we do our boat engines????? The overall load we apply to the car or truck engine is a lot less than we expect of our boat engines.
But in answer to your specific question, IMO, the HE and circ pump only weigh about 50#. At least it was for the Minx's full system HE and Meziere pump.
You know they can be mounted on a stringer below the engine and the Meziere remote pump I used can be mounted in many places.

MOP
11-30-2007, 09:48 AM
But Joe, outboard innards have a very expensive coating added during manufacturing. Also they have a lot of anodic protection.

Can't agree with you George, having worked on O/B's for many years the only anodes are the same as on an I/O for lower unit protection. However I do firmly believe in having an anode in the water intake line before the engine, I have made and teste several it does retard electrolysis. I made them up for my boats and several customers, it is a simple a fair that I more then proved extended the life of both aluminum and cast iron. It is pretty well known 5 years is pushing cast iron in salt, with the anode it jumped to 7. Not bad for the initial cost of about $30.00, a few hours work and a annual cost of $6-8 for anode replacement.

Phil

BERTRAM BOY
11-30-2007, 10:40 AM
Here are the coatings copied directly from the Dart page. Mario are you referring to the DC-7 coating? Also, I 've always heard that hard annodizing is the way to go. What info have you found that confirms that dart's coating are are better suited for a marine environment? I'm also looking into aluminum heads for a marine application.





DCI MOS2 Teflon Skirt Coating

Reduce Friction

Prevent piston skirt scuffing and galling, extending piston ring seal life with Dart’s exclusive DCI MOS2/Teflon skirt coating.

(*Used pieces can be processed and build up can be accommodated when requested).



DC2 High Temperature Reflective Heat Barrier

Protect and Enhance

Protect piston tops with DC2, Dart’s high temperature highly reflective heat barrier. Enhances flame propagation, reflects more heat into the combustion chamber and off piston tops, piston rings and lands.

Ideal for any high temperature- heat reflective/insulative application. (Combustion chambers. valve faces, exhaust port, intake manifold, brake caliper/pad/piston).



DCB-3 Engine Bearing Coating

Dart’s engine bearing coating is a molybdenum disulfide/Teflon based material with high-load/non-stick properties providing protection to bearings and crankshaft in case of lack of lubricant or detonation.



DC-4 Lubricating Pigments

Lubricating coating contains a combination of lubricating pigments, including MOS2, creating exceptional wear life and load capacity in applications such as valve springs, oil pump gears, ring and pinion, transmission gear and bushing, valve stems, timing gears, bearing races, camshafts and any friction related area.



DC-5 Oil Shedding Coating

Oil shedding coating for applications in which oil and other petroleum liquids should be shed off rather than retained on a particular piece such as crankshaft counterweights, inside oil pan, windage trays, inside valve covers and connecting rods.



DC-7 Anti-Corrosive Protectant

Anti-corrosive protectant coating for application in an environment of exposure to weather elements, gasoline, alcohol, nitro methane, brake fluid and antifreeze on varied types of materials including magnesium.

Pismo
11-30-2007, 02:20 PM
Coating couldn't hurt and it's very cheap so why not but in fairly clean fresh water you are not going to have any problems anyway.

VetteLT193
11-30-2007, 02:45 PM
Mario, I apologise if I was a bit blunt, above. IMHO, if any of us were to buy a new car, we wouldn't even consider not having antifreeze in it, and not just for warranty reasons. Why would we build a $6K-$10K engine and do any different?????????????
If I'm wrong, screw the car warranty and just put water in it and never do any other maintenance!:smash:
Why do we take better care of our car and truck engines than we do our boat engines????? The overall load we apply to the car or truck engine is a lot less than we expect of our boat engines.
But in answer to your specific question, IMO, the HE and circ pump only weigh about 50#. At least it was for the Minx's full system HE and Meziere pump.
You know they can be mounted on a stringer below the engine and the Meziere remote pump I used can be mounted in many places.

I'll agree with using closed cooling in a boat that sits in the water for extended periods. Other than that it's a waste of weight and complexity, especially if you are good about using some sort of product like saltaway at the end of the flush.

I've never seen FWC as taking better care of the engine in the case of a trailer boat.

smoothie
11-30-2007, 02:55 PM
Btw, what are outboards mostly made of?
And what are aluminum boats made of ??? Ive been restoring a few 1950's outboards and the water jackets are fine after 60 years in fresh water...salt water is a different story..BTW the L88 aluminum heads where like new after 25 years when I tore it down to change the compression on my cig.

f_inscreenname
11-30-2007, 05:19 PM
This aluminum part cost me a very good and strong 360ci motor.
http://i21.photobucket.com/albums/b264/f_inscreenname/12.jpg?t=1196464147
It's a timing chain cover for a small block Mopar. The water pump bolts to it and acts like the backside of the pump. Also the whole thing was powder coated about 6 months prior. As you can see there is no powder coat and there is a hole that let sea water pump straight into the block at WOT. :doh:
Not saying not to use aluminum (that's why I have a aluminum intake and exhaust manifolds on the 454 I just built) but be very selective.

mphatc
11-30-2007, 05:28 PM
A few quick things ,

Part of the problem for us running automotive based engine in marine applications is the alloy

Aluminum heads are made from a totally different alloy than aluminum boats and sailboat spars . . all of this is hard anodized . . and consequently reacts diferently to anodization . .

Anodization is supposed to have some effect on heat transfer, essentially slowing it down. Not good for cylinderheads. Outboards are again a totally different alloy.

Antifreeze in automotive engines, sorry, I build road racing engines, they run on distilled water and Redline Water Wetter .. . only! No corrosion protection additives. Note, I know of no automtive engine that has brass or bronze in the cooling system . .
Again the disimilar metals and corrosion

Automotive warranties are there for the owner that never cares for his vehicle. My boat will be treated ike most every other properly cared for boat that is trailered . . it drains itself partially and the rest gets flushed.
For those that need to leave them in the water especially salt there are closed loop cooling systems.

I have seen 3/8 galvanized mooring chain rust away in one year in fresh water when installed with a brass shackle . . normally they last 3-5 years.

As for my concern in fresh water .. I lost the last engine, the 3rd in my short ownership when my H&M logs failed and I sucked water into the engine through the exhaust port after a 15 minute run at 4800 rpm . . which fwiw was the absolute best run and most fun I ever had in the boat :).

I also removed my 1 year old aluminum intake manifold when I went to rebuild the original H&M 302 . . the water passage was very corroded and crusty after 15 uses. This really surprised me. From all I can tell many of these aftermarket aluminum pieces are not made with the quality of the alloy that you'll find in factory aluminum pieces. I see this with repalcement parts on BMW engines all the time, BMW aluminum rarely corrodes as fast as all the aftermarket parts . . . I'm not a metalurgist .

George, we discussed my electric pump a long time ago, it's not so much the weight and the two pumps, as it is the small access thru the Coriscan hatches, and my ability to service it in the years ahead. As I Age I loose flexibility and at 6'2" I can't get in to the front water pump. :eek!: . . Weight is a concern, as the Bravo weighs more, the CMIs are heavier than I ever expected, and I increased the fuel tank to 44 gallons . . . I guess the racer in me says KISS and light . . . :smash:

Cliff, I believe it is the DC-7 . . review the thread on the Dart Boards that I started if you can excuse all my BS at the beginning. TYhe answers may help to explain some things . .
http://www.dart-machinery.com/dartboard/showthread.php?t=41


TGIF,
i'm off to marguaritaville!!!!:drunk:

Mario

Pismo
11-30-2007, 05:38 PM
Salt is a killer..............

Cuda
11-30-2007, 05:46 PM
Salt is a killer..............
Why hasn't my boat been buried?

Cuda
11-30-2007, 05:48 PM
But Joe, outboard innards have a very expensive coating added during manufacturing. Also they have a lot of anodic protection.
I must have missed all this very epensive coatings on any of the outboards I had apart. They all looked like steel gears to me. I also missed all the anodic protection. Where do they hide it?

Cuda
11-30-2007, 05:57 PM
My main gripe about closed cooling, is all the space it takes up. I installed it on my 20 Formula when I first bought it, because it had an aluminum intake, and I had read that salt water gives aluminum AIDs, or worse. I have since found this not to be true at all. Not only that, I spent $600, and a ton of my own labor installing it. All this to protect a $100 intake.:confused:

I put that engine in my Minx, and it was no fun getting down in the bilge before the CC. It really sucked after I put the engine with the CC in the boat.:bonk:

Most of the people who are against aluminum in any form on a salt water engine, are usually from fresh water only areas. I've done 99% of my boating in salt water, so my observations are not conjecture, but real life experience. I should have taken pictures of the inside of the aluminum intakes, when I had the thermostat housings off. This bias against aluminum, almost make it worth doing again.

mphatc
11-30-2007, 09:09 PM
Cuda,
I'm with you on the closed loop cooling , weight and space issues. I had initially considered this path as everyone said that engine efficency went up, and as protection against freezing as I go boating with a trailered IO when we have freezing temps at night, spring and fall. I believe that is what ruined my H&M manifolds.
I do know from what you have written in the past few years that you are an enthusiast about your boat collection . . and likely rinse after every saltwater bath . . and you keep your boats clean. That's why the aluminum is still there.
f_inscreenname . . not meaning to be in your face, but powdercoating internal coolant jackets does not work. It expedites corrosion by trapping water and air between the coating and the base metal.
Mario

f_inscreenname
11-30-2007, 09:21 PM
f_inscreenname . . not meaning to be in your face, but powdercoating internal coolant jackets does not work. It expedites corrosion by trapping water and air between the coating and the base metal.
Mario
So my attempt to help actually made it worse? Now that's just to f_in sweet.:bonk: It's just been one of those days.:boggled:

yeller
12-01-2007, 04:20 AM
This aluminum part cost me a very good and strong 360ci motor.
http://i21.photobucket.com/albums/b264/f_inscreenname/12.jpg?t=1196464147
...Also the whole thing was powder coated about 6 months prior....That has to be the worst case of corrosion I have ever seen in a 6mo. period. What were you running it in...acid. Sorry if I sound harsh, but I just don't buy it. How is it your aluminum intake and exhaust held up. It's all the same water.


Salt is a killer...Sound like a fresh water boater.
Storing a boat in salt water will corrode faster than boats stored in fresh water or trailered boats....but ask anyone that boats in salt and flushes religiously and 9 times out of 10 you'll get the same answer........No problem.

My intakes were automotive aluminum intakes and each one was on for 4 to 8yrs and there was no sign of corrosion on any of them.

I've been trying for years to get my cousin to come down from the interior to boat on the coast, but he won't do it. His response is always the same....."WTF, salt water...you have to be kidding." SALT WATER IS NOT EVIL. YOUR BOAT WILL SURVIVE. NO ONE WILL KNOW.

Ok...I'm sorry...I'm done.

BigGrizzly
12-01-2007, 08:31 AM
I will be blunt, First I worked For American Honda Motor Co. in both the auto and marine devisions. We have used dissimilar metals in our engines since the beginning of our products in the 1950s on motorcycles and autoa in the 1570s, and marine engines since the beginning. I also have a friend who is the son and co owner of Whitford coatings who does all the coatings that honda uses under a different label. They are very expensive and may not work as well as perceived. Now the blunt part. Poodle is completely correct. Every time we had a corrosion issue and have inspected it , grounding was the issue, from Main To the Grand Bahama's. Since I was in engineering and Warranty administrator I have access to all the data. The thermal heat distribution is much better in the closed loop system. My system on the Criterion-aluminum heads and 502 cast iron block, is 42 pounds total increase, from the crossover system to the closed system. Because of the crossover system I dropped an exhaust valve during prop testing in 2000, with Poodle on board. My Corsican System never had a cross over system, so I don't know what the original, weight is without the circulating pump. But that exchanger is old style and too big and weights 44 pounds. It is also the only addition to the Corsican for the system. I dropped several exhaust valves in it due to the horsepower and LOG manifolds. This I have confirmed with several engine builders and other owners of these boats. Now I have a 351 Ford Cleveland engine which quite different than most other engines. However the problem does exist in both small and big block Chevys, this has been confirmed many times. I have CMIs on my Cleveland for two reasons. One because at the time no one would make me a set except them, the other was I was tired of blowing engines and the separate tubes cool the exhaust valve train of the engine. That was in in 1993 and the engine has not been apart since. On the Criterion I used CMIs also. This reason was because I deal with them and we built the engine around them, It just took me awhile to get the cash for them, but my Hardings were up to the task of the engine (BTW they are for sale). I have over 800 hours on that engine combo with a Procharger. Our 1966 16 H&M rotted out the t-chain cover from the outside in due to water trapped in a valley on the top-got under the paint, rest is history. As for Florida type boaters, many run in both brakish water and salt water. so this helps. As for Cuda, regardless of what he says He does take good care of his equipment.
He is a contractor and equipment is his life like me. There are thousands of raw water systems that seemingly have no problems in salt environment. However I have not been so lucky in my boating existents. A battery switch does help some of the problems too. The End

MOP
12-01-2007, 08:54 AM
Salt is a killer..............

Mine too! My 86 22 had the Tempest engine it came with a Performer intake, no telling where it had been in its life. I ran it in salt then sold the engine to MadDad who continued in salt, it was still running the Performer when it finally died due to an unrelated issue.

MOP
12-01-2007, 09:12 AM
f_inscreenname as you know I was a marine mechanic for many years, I never saw a Chrysler Corp engine not equipped with F/W cooling they came that way for the reason of the aluminum parts. Yours was run with out F/W cooling! If that damage happened in 6 months I will also bet you were on what is called a "Hot Dock" meaning it had stray electric current running int the water. I have been around this stuff all of my life with way to many years of hands on, aluminum does pretty darn good on its own. Granted less time than cast iron, but properly protected it has more then proven itself to be very hardy.
Phil

gcarter
12-01-2007, 10:49 AM
My main gripe about closed cooling, is all the space it takes up.


Wait till I get the red boat finished.......:smash:
All I'm gonna say.

BigGrizzly
12-01-2007, 11:53 AM
Look at my Criterion, everything is below the engine except the surge tank which is above the block. I have to point it out to people. The Corsican is more noticeable but not by much. As for the weight I just cool the drinks and leave the ice at home. I just realized our 16's closed system is now 36 years old and no problems.

f_inscreenname
12-01-2007, 03:03 PM
It was longer then 6 months but it was 6 months use. Here is a time line.
Fall 2005. Bought new Hi Tek manifolds for it and did a cam change at the same time. I also changed the timing cover from the cast iron to the aluminum because I broke a ear off the old one and it would not seal the water pump right. Did that. Drove it for about a month and was happy as a pig in crap and could not wait until spring before I put it away for the winter. Over the winter I found a 280T transom shield and when spring came I installed it kind of killing off a couple of spring's early months. The 2006 summer was awesome. Then this happened on Aug 8th around 12:30am (I remember because it was a half hour past my birthday).
http://www.supernova19.com/3ebae800.jpg
I was just as shocked as the rest of you. Trust me. I even wrote a nasty email to HiTek saying when I proved to them it was their manifolds, what were they going to do about it? I ate a lot of crow for that one.
The intake and the manifolds were fine.
I then spent the next 30 days hunting boat junkyards for a 30+ year old, cast iron cover, payed a mint for it and then had to JB weld the hell out of it to fix it.
If you want to check the movie out of what I call "33 days of hell". http://www.youtube.com/watch?v=y88TTrR8QC8&eurl=
Turn the sound down if you have sensitive ears. I was a little pissed off.

mphatc
12-01-2007, 06:03 PM
f_inscreenname
Like Grizzly mentioned with his 16', his aluminum timing cover corroded away with water trapped under the paint. I powdercoated my first timing cover, it was the original piece, and inspite of thorough glass beading, and very careful prep at the gasket surfaces, where ever there was existing corrosion in the aluminum it returned in a big way after getting wet . . I suspect that your piece had some corrosion before powdercoating.
We powdercoat aluminum intake plenums and cam covers on the BMW M engines when we rebuild them, and the powdercoating shop I now use insists on blasting all pieces just before they apply the powder . . as the aluminum immediatly oxidizes . . I suspect this is what killed your timing cover.
Randy,
well written post . . . I don't dispute the control of corrosion and grounding . .and the thermal equilibrium with a closed loop system . . . it does a better job especially for engine running in extremely cold water . . .northern lakes like my use.
I have the complete closed loop cooling sytem here on the shelf, made especially for my application, oversized HX , custom oil and ps cooler . . . etc..
So why do I not want to use it . . . complexity and weight . . which is why I started to look for additional corrosion protection technologies. It's the engineer in me . . .
You know all to well how small the Corsican engine compartment hatches are, especially after you add the high rise CMI's . . now install a power steering pump, an additional circulation pump, alternator, and the crankdriven pump on the front of a 302. The original set up from H&M was with one belt for the alternator, and then I added a PS pump and doubled the v belts . . but to change V belts with the crank driven pump is a huge challenge, and largely invisable once I added the Mezeire pump. The electric circulation pump is required because the engine mounts using the original H&M steel plate on the front of the engine, and this covers the recessed surface in the timing cover that allows for a belt driven conventional circualtion pump.
Leave it that the front of this set is been a bit of a challenge to fabricate.
By eliminating the closed loop cooling system, the Meziere goes away along with lots of plumbing. The front drive set up will now be a single serpentine belt.
leaving only one item that need access down low on the front of the engine, which is the Johnson freshwater pump , stuffed with a polyurethane impeller.
Weight . . by switching from the Volvo to the Bravo with no other changes to mechanicals that effect weight the boat floats 1 1/2" lower at the stern.
This has to be from the PS system and all the drive components. Adding more weight at the stern will place my stock exhaust outlets below the waters surface . . something I really don't desire. And cutting new outlets in the transom is not an option.
I also tuliped intake valves unlike your experience Randy. I found water in my cylinders when we pulled the engine apart. Fortunately this was done within an hour of the incident. My H&M logs fractured in cold weather :(

But we went way off topic here . . my whole point with the corrosion protection offered by Dart Machinery is that many folks want to run aluminum heads, many have been reluctant to because of the concerns about corrosion, justified or not. Not everyone flushes, rinses and carees for their boat engine like we might.

IMO, for $75.00 per head I can protect my expensive AFR heads, with custom porting, and machine work etc, without sacrificing the heat transfer properties of the aluminum. Until I found this technology I was prepared to run the closed loop cooling system as prevention.

Mario

f_inscreenname
12-01-2007, 10:58 PM
Could have been anything but I will never do it again. I have it apart now because of a unrelated issue a month later.http://bestsmileys.com/dead/1.gif The JB Weld/cast iron looks as good as the day I put it in.

On a side note, when you went to from Volvo to Merc did you get any gains from it? My boat also sank some when I installed trim on my Volvo but only a 1/2". The Merc must be heavy.http://www.supernova19.com/forumcw/Smileys/classic/clueless.gif

BigGrizzly
12-02-2007, 04:03 PM
Thanks Mario. Because of your information I called Chamberlin, and I had the number of the original pump Dick Chamberlin found he had it in stock but didn't realize they superseded the number. Unfortunately it is one of the most expensive pumps on the market. I was able to bring it back to the original configuration. which only needed the heat exchanger and surge tank. two separate pieces. I mounted the heat exchanger on the port side under the exhaust system and the surge tank just above the T-stat housing. so there was nothing in front of the engine that wasn't there before. the surge tank is just under a quart capacity. One little detail, I use a teleflex PA unit so I don't have a manual power steering pump on my engine. Thanks again Mario for your help!! I could not done it without your information, at least not that fast as fast as I did. I hope the coating works for you.

RickSE
12-03-2007, 08:39 AM
Anodizing is not a surface coating and should not significantly impede heat transfer; it's nothing more then the creation of an aluminum oxide layer on the surface of the part. Without die, anodizing actually incerases the surface area of the part. More then likely Dart is anodizing their cylinder heads according to one of the three types if they are locking a dye into the surface.

Type III Anodize, is classified with excellent dielectric and heat transfer properties from our anodizer.

VetteLT193
12-03-2007, 09:31 AM
This aluminum part cost me a very good and strong 360ci motor.
http://i21.photobucket.com/albums/b264/f_inscreenname/12.jpg?t=1196464147
It's a timing chain cover for a small block Mopar. The water pump bolts to it and acts like the backside of the pump. Also the whole thing was powder coated about 6 months prior. As you can see there is no powder coat and there is a hole that let sea water pump straight into the block at WOT. :doh:
Not saying not to use aluminum (that's why I have a aluminum intake and exhaust manifolds on the 454 I just built) but be very selective.

I'm not counting any Mopar water pump failures. It's the dumbest design of any water pump. I still have no idea what they were thinking with that.:bonk: