The elusive 224/3.7 MerCruiser banger

quick question:
I looked through 30 boxes of water pumps today hoping to find one suited to use on this engine.
All that I saw had half of a housing leaving an open impeller. Does the little old Toyota pump mentioned earlier have a back on it?......an internet check shows that they do have backs on some of them.

 

As there is no margin for error in making an oil pump alignment tool, mine was not good enough. However,I figured out another way to position the pump. Mounting the pump on studs which had a thicker center section took out most of the movement of the pump. I shimmed out the rest of the slop with a single wrap of the stud with a shim cut out of a soda can. Its positioned.

 

Dennis,

Here are some pictures of the Toyota Corolla water pumps.

The first set of pictures is of a 78-82 Toyota Corilla Statlet pump listed on ebay for $29.95 + $10.95 shipping.

The second smaller one is a 71-74 Corolla pump listed on ebay for $24.99 free shipping.

I will mount the smaller Corolla pump on a piece of 1/4" aluminum plate drilled for mounting and tapped for a pipe bib outlet.

Either one will work equally well, I just like the smaller, less expensive one because it looks like it will be easier to mount.


Dick
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dawford,

Thanks for the pics- can you give some measurements on those water pumps? I'm wondering if they might work for the early Chevy 4... hmmm...

 

I bet you can drill and tap the pump housing,ad use a flat plate on the back,i would try that for sure.

 

Mac,

The 71-74 Toyota Corolla water pump would bolt onto a 4 1/2" by 4 1/2" square plate. The big tube would extend an additional 3 1/2" for a total width of 7" and the small diagonal tube extends about 1 1/2" out from the big tube.

The pump measures 4 3/8ths" from the back of the original 1/8th" cover plate to the tip of the pulley mount. With a 1/4" aluminum mounting plate installed it would be 4 1/2".

The larger pump for the 78-82 Toyota Starlet is about 1/2" larger in everu demension.

I don't have a pulley yet for the smaller pump but I suspect that it will have a setback similar to the larger pump shown in the first photos.

The pump is small however the internals are of close tolerance and should have enough flow to adequately cool most small engines.

I always remember that the thermostat when fully open only has a 1" somewhat restricted opening.


Randy,

I'm sorry I didn't fully explain what I meant by mounting the small one on an aluminum plate to facilitate mounting to the engine and allow for the installation of a hose bib on the outlet.

So your comment about drilling and tapping the pump housing is right on and is what I was trying to convey.

Dick

 

If a freeze plug was used to keep the coolant out of the cam bore, one could still use some of the Merc waterpump as a coolant passage to the belt driven pump.

It looks as though an aluminum plate [ with a coolant hole] could replace the front half of the Mercruiser pump providing:

1. a place to mount the pulley driven Toyota pump

2. coolant flow between engine and new pump.

an alternator could be used as a belt tensioner for the water pump.
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A man I buy used mercruiser parts from has a number of cams with bad noses. That says that the Mercruiser cam rusting problem behind the waterpump impeller is common in used engines. so a belt-driven pump is a good option to beat the corrosion issue.

 

Randy, did you run the Merc water pumps or did you replace them with something else on your engines?

 

As long as we are making a rear plate, our choice of pumps widens to include larger pumps( if they are desired)

 

Here is one other water pump, that of a toyota landcruiser 1968-74

 

I drilled & tapped deeper holes in the block for my bellhousing. Boring a hole down the center of a 3/8" bolt for a drill guide made it easy. But for the one hole which misses completely, I made an heavy "L" shaped aluminum hold down ( like the one which holds a distributor down) that will clamp the bellhousing to the block where the holes don't line up.

 

I finally found "perfect seal", in a boat repair shop. No one else had ever heard of it.

As it is so hard to find there is much speculation as to what easier to find alternative there is. So here is my speculation: It is the color, viscosity and has the odor of the Volkswagen case sealant "Kuril". Kuril's availability relative to perfect seal's availability is probably the ratio of Volkswagen rebuilders to Mercruiser rebuilders. Perfect seal was not as messy as kuril which was absolutely awful.

 

I am assembling my motor. Here are pictures showing it is close to stock.

 

I used an electric water pump that i bought on ebay.

 

Dick
I have a question about the starter you use. I tried for a while to find the modell, can you read the modellnumber and brand (ordernumber) for me I be happy. I have been on a long hollyday, but I see that you guys have not been lazy.

/ Johan

 

johan,

The model number is IMI 302.

See pictures below.

I purchased 2 of them from Quality Power in Yucaipa, California about a year ago.

They are listed on ebay 260402261233 at $235.00 including shipping to USA.

They will probably charge you extra to ship to Sweeden.

The one that is positioned on the engine is one that I originally bought on ebay listed as a Mercruiser 470 high torque starter.

It is marked IMI 302B. They cost more because they are probably certified by the US Coast Guard as Marine starters.

That first starter is what led me to research it's source and discover that it also fits an International Scout truck.

They seem identical to the IMI 302 starter and have the same mounting, rotation and number of teeth.

There are 6 advantages to the these starters. They are smaller, they weigh about 9lbs vs. 21lbs, they provide more torque, draw less amps, they can be rotated on the mount to clear other parts or to reduce exposure to heat and they don't require the extra nose bearing that sticks out so far that an auto bellhousing has to be modified to allow them to fit.

In the last picture notice the carpet. Not every one has an engine on their living room floor. The only advantage of being a Widower.

Dick

 

Dick that is a big improvement on the starter. The original mercruiser starter is 8% of the complete motor weight. I'd love to get rid of that big clunky starter. the little ones weigh about a third as much.
dennis

 

Randy It seems that the front water spigot on my intake manifold will run right through my distributor.
I can see using a street ell, or possibly a different distributor cap. What detail have I missed that makes it all fit? A coil pack?

 

dennis,

That problem with the distributor being in line with the water outlet is one problem that I didn't see comming. Glad you brought it up.

If you need 2 outlets I would use a street ell.

But after doing a quick mockup setting a head on the block and plugging in a distributor I thought about how the water would actually flow thru the block and head if both the front and rear head water port were used.

I have cut off the camshaft water pump extension and blocked the hole in the front cover where the extension came thru to drive the water pump.

I then modified the front cover by machining off the stator mounting bosses to allow the new harmonic balancer fit without possible interference.

I then epoxied in the 3 bolts that held the waterpump cover on but didn't hold the main cover onto the block because otherwise they would leak oil..

I then cut the short piece of the water pump cover that is immediatly over the water opening into the block and epoxied (JB Welded) that piece in place and plugged the cut end with epoxie.

I then drilled and tapped the side of the cover to allow a pipe bib to be installed.

This allows the Toyota water pump to pump into the block from the side giving me a little more room (about 2" more) between the radiator and the front of the engine for the electric fan.

See picture below.

Anyhow with this setup where the water enters the block in the front I thought that most it would follow the path of least resistance and immediately leave the engine out the front of the head.

Soooo I think that I will only drill and tap the rear of the intake manifold thus forcing the water to flow thru the whole engine from the block and thru the head.

Later if I decide to heat the intake manifold I might use the front head water port to facilitate that.


Dick

 

Dick

thank you for your quick reply, I think I buy one of this starters, then I can cross out one thing at the list of "buy or to do". Well regarding your livingroom carpet, I have a wife so that the answer to my situation, I better be in the garage.

/ Johan

 

dennis,

I see from the pictures of your painted engine that you have installed the harmonic balancer.

Does it look like the marks on the balancer will line up with the marks on the cover?



Johan,

I was telling a friend of mine, Kim Sparks about your project and how much more difficult it must be for you to build your project in Sweden than it is for me in Southern California.

Kim was talking about driving to Thousand Palms, California (70 miles) to Red's Headers to get a Header and other things for his Model A Ford flathead.

Kim must of asked them about my project because he said that Red's had made a header for the 470 Mercruiser.

This morning I called Red's and talked to Jim who said that he would send me some pictures of the one that they had made and that they had the spec.s for a Model A installation.

He further stated that headers can provide as much as a 10% increase in performance over a stock maniford.

If I could get even 1/2 that increase in performance that would be about equal to a 12hp increase or 120lb decrease for a 10 to 1 hp to weight ratio and would be well worth the money.

Thanks Kim for the heads up on the headers at Red's.

Thanks Jim for the pictures.

Dick

 

Total ignorance question here... is it possible to reverse the head on a Mercruiser so that the exhaust is on the other side???

 

Nope, it's a pushrod motor, so the side of the head which is engineered for that, always has to sit over the camshaft.

 

Dick

It´s really possible to get 10% more gain if you make the header to the specification of the engine, but I can promise you that the gain will be at least 5 % or more anyway. You just have to look at the stock exhaust manifold from the most older marine engine to see that they dont work at all if we are talking horsepower or torque. I would go for that header if I where you. About my project I guess I like to go the hard way and make the most of part my self ( every horsepower or torqe gain in the engine is the dubble with 15 psi of boost, I learned by the years). I also lucky to have a good friend that do all my calculations to my engine, and internet really open doors for people like us and made it easier to get a hold of things.

/ Johan

 

... should have realized that - thanks!

 

johan,

I wouldn't try to use an aluminum exhaust maniford such as is on the original Mercruiser.

In the water cooled mode that they use they work fine and I don't know about their efficiency but do know that Mercury Marine Engineers knew about marine exhaust.

I have a couple of 370/429/460 Ford cast iron side dump exhaust manifolds that would work fine and would flow pretty well but I do think that I will get at least the 5% increase with good headers.

Note: There are 2 of these manifolds that were aparently used on busses.

The 2 that I have are the ones with the larger ports. Some 460 manifolds have ports that are about 1.5" by 1.5" while heads with the larger ports are about 1.5" by 2.10"

The opening to the head pipe is about 2.36".

These heads will work fine with the Vega steering box and the side motor mounts.

They might not work so well with a stock Model A steering box but I am not sure about that because I haven't installed one in a car yet.

Dick

 

Dick

Sorry I tought you where going to use the marine exhaust, but I still go for the header if I where you just think of the gain, and lost of the weight also at the same time. Again thank you for the information about the starter.

/ Johan

 

johan,

Are you using an aluminum head and are you using the Mercruiser rods with your 15 lbs of turbo?

If you double your hp with a turbo and get 400+ hp that would be the equivalent to getting 800 hp in a 460 V8.

I think the bottom end will stand 400+ hp but I would be concerned about the Rods.

I believe the original rods are Ford 429/460 heavy duty but wonder if they will stand 400 hp.

I am just curious because I have thought about using about 5-6 lbs of turbo with the 8.8 compression ratio to boost the hp to maybe 300hp.

And even at 300hp I might be concerned about the connection rods.

Dick

 

Mac,

Are we starting to affect your plans to install a 2.4 Quad 4 in your T-Speedster?

I have thought about building a Model A Speedster using the Mercruiser - T5 combination.

If I did I would leave the sides off of the hood and paint the engine Ford sea moss green or whatever they call it. (I call it barf green).

That way all anyone would see a 4 cylinder carburated engine that has a good 4 cylinder idle.

No High Tech plumbing or wireing just something that looks like a tractor engine.

Then when the signal light changes they would get a good look at what the rear end looks like.


Dick

 

Dick, I positioned t he first piston exactly at tdc and made a new pointer to line up with the right spot on the dampener timing marks. I painted over the other sets of marks to reduce confusion. My pointer hides the cover's marks which would be of no use anyway. You might as well grind them off the cover.