The elusive 224/3.7 MerCruiser banger

New oil pumps for this motor : Melling #M-138. Found several on Evil-bay in the $70+/- range. Hope this helps out, if someone needs one.

 

Dennis,
I have looked & looked at Toyota pumps but can't find a pump that looks like the one you are using. Do you have any other info? Part #, year & motor ?
Thanks Dave

 

1978 toyota corolla...there was only one motor.
I went to a Knechts auto parts store and they let me open every one of their water pump boxes. Several will work but I picked out the one that looked like it would fit best.

I rotated the pump to fit the engine, so look at the bottom of it to compare with the photo because the pump fits in upside down. Never mind its drain hole, another can be drilled if desired.

You can email me for help when you need it.

 

Rootsgroup,
You could go with a flex plate & starter. Then bump start like we do our V8 sprint. It's easy.
Later Dave

 

Corona maybe? It had one motor 20R. Corolla had 2, 3KC "1200" or 2TC "1600".

just trying to help.

 

NONHOG,
The 20r & 2 or 3 TC are a no go. I will be using the 71 to 74 3KC (1200 ) pump. I will turn it up side down so the inlet will be about where the stock 244 is ( right side ).
Later Dave

 

That(3KC one) will work for you. The pump has flowed an adequate amount of water for my engine's cooling. I just lined its outlet up with the block inlet of the mercruiser pump. There will be a water filled space between the two, but it is not a bad thing, mine trapped and removed sand from the coolant and saved a having a plugged radiator..
As it has no real function, the "water gap" could be filled in as long as the filler would not melt or dissolve.

 

Oh, you let the cat out of the bag!

But yeah, even if I have to have a gentle assist from Bro's 4-wheeler that's gonna be the easy way out. Plus testing at home, warm-up in the pits. some of our guys do that.

 

I use electric fuel pumps, and they were overpressuring my carburetors in two differernt cars. So I added fuel pressure regulators and found that the Mr Gasket regulator left a wet spot on the floor and my fuel tank was empty. The Holly regulator I bought from a friend would not adjust below 5 psi.

So here is what I did:

I plumbed in a pressure bleed line from the high side of the Holly regulator back to the low pressure side of the fuel pump. A needle valve adjusted the pressure down to where I needed it.

I moved the Mr Gasket regulator to a loop in the fuel line above the fuel tank where fuel can not slowly leak away while the engine is off. I was told that all of the little round regulators leak. Not surprising as they look the same and probably come from the same factory in China.

 

Dennis,
When I ran a 4cyl sprint car ( Toyota 2TC ), I used a Hilborn pump. Holley has two regulators. A high & low pressure. With the Weber dcoe 40 mm I used the low pressure. I switched to a Holley 2bbl & the high pressure. Never a bit of trouble.
Later Dave

 

Thanks Dave,
My holly regulator is with a Hitachi carb which does not require much volume and floods when the pressure exceeds 3psi. The Holly seems to work very well when there is some flow but it seems to seep fuel pressure when there is almost no flow. The other regulator is on a motocraft/autolite 2 bbl carb that I like.
dennis

 

progress? on the question of mercruiser engines knocking:
Those following these posts may remember that I wrote that my engine seemed "knock proof".

I am using higher swirl in the combustion chamber and attributed it to that.
It was also running a rich mixture
Timing was stock.
However things were not perfect as it would commonly maroon me in random places.

Thus I made some changes to increase reliability. I had been warned that the distributor which I bought needed rebuilding and that the plug wiring I used could be shorted out at its exposed terminals. I changed to new plug wires and mixed and matched parts of four distributors to get a single reliable one. While doing that, I added a vacuum advance section as two of the distributors had that.
In measuring valve lift, I found that the camshaft had worn on a few lobes and needed replacing. In went a new cam.
As I could now monitor mixture with my wide band oxygen meter I leaned it to run at 13.5 to 1. And I cleaned the carb idle passages with a fine drill bit...finally the idle mixture adjusts.
--------- the results:
It now was reliable. That had been a serious problem.
however the engine knocks in neutral at idle.

A mechanic friend limited its advance to 28 degrees but after he left I advanced to to 30 @ 2000 plus 2 degrees from vaccuum.
It knocks again, I will enrichen the idle mixture. Perhaps I should use high octane fuel. I will try that before making changes .

 

Ive been tossing aroung the idea of installing one of these motors in my prolite off road race truck. What kind of horse power could i expect to get from it and do you recomend any builders in Az

 

HP would depend on compression and cam and more. If you get an aftermarket aluminum head, 4 bbl carb, otherwise stock I think about 230 HP would be ballpark - 1 HP per cubic inch. It would be light and small and shaky due to "big inline four" design.

If I had more money and space I'd be working on one of these right now. They are mighty cool. But they aren't plug-and-play, there are some issues in putting a boat motor in a car, mostly addressed in this thread.

 

I have built several of these engines over the years. I never cared much for the design...aluminum block with cast-in free standing iron liners. I wouldn't think they would stand much more horsepower than they already make stock.

I used to do a lot of boat work - every one of these engines I ever worked on was usually a "swap out" deal...because the original engine would be blow'd up so bad I had to shovel the remains of it out of the bilge after I removed the biggest part...lol.

I have some pictures of one I worked on one time...

Here's the #4 piston out one I worked on one time...



The block...



This is what happens to em when the prop gets out of the water at WOT

 

It is a very light engine with good torque but has some disadvantages. Some are easily fixed but others are much more difficult to deal with.

1. Some easy to fix problems:

a. the cam drive for the waterpump. This was never effectively sealed by mercruiser and ended up in antifreeze leaking into the oil and siezing the engine spinning bearings or worse yet putting a rod through the block.

Wear of the camshaft at the seals is much faster than one would imagine, I saw wear beginning after 200 miles . Solution, cut the cam, block it of with a welch plug and mount a belt driven ot electric pump.

b. Mercruiser alternator. It works until the weights fall out. Just replace it with a harmonic dampener. (The alternator's weight makes it a good dampener.)

c. Mercruiser water cooled voltage regulator. Present alternators have the voltage regulator built into them, so changing alternators solves this weakness.

d. head gasket leaks, use a mercruiser gasket. everything else leaks.

e knocking:
in a car you can us 9.3:1 as I do
but for sustained operation at open throttle, the advice is to lower compression to 8:1.
Cam profile relates to this also
So does zero decking the engine
ignition advance should be around 32 degrees at 2000 rpm and not go a lot beyond that

f. cam lobes wearing out. use oil with lots of ZDDP in it Valvoline racing oil in the silver bottle The best solution is a roller cam, but I'm unaware of anyone ever runing one.

g. expense: It is not at all a cheap engine. Some parts are expensive some are cheap others are simply unobtainable as the engine has not been made for about 20 years.
solution: throw money or use a toyota or the bellybutton engine, the small block chevy.
you can do 3 small block chevrolet engines for the cost of a mercruiser
h. open deck construction. use "hardblock", otherwise limit the power to modest levels.

2. the hard one is parts. You will have to use some used parts. Not all of them are good.
It is not like going to the A&P for a bag of carrots. At times you may have to be able to invent & make some of your parts. Just try to find a new camshaft or timing chain tensioner

The Mercruiser expert Randy Dupree went to using Toyota engines. He says they make more power. Class rules made Mercruiser the best choice for me. Otherwise I'd not have used it.

 

I've had two camshafts in my engine, and although they are generally alike, I was happier with the reground cam with its "RV" profile than with the boat cam.
With the RV cam, the engine had more torque, did not knock and used less fuel.
The "boat" cam used more fuel, knocked at idle and seemed to have less torque.
I guess it seems like a car cam is better suited to a car.

 

Dennis,

As thorough as you are, I'm sure you must have specs for both grinds. Please tell us the difference between the two cams.

 

This is the card for my preferred cam. One of my lifters was not spinning well and wore a lobe a little so I replaced it. Even worn, I preferred this cam to the one which replaced it.
click on the image to enlarge it.

 

these are dial guage measurements that I made with the camshafts mounted in my lathe.

As one end of the camshafts were mounted in a 3 jaw chuck there will be imprecision in the measurements. The other end was held in a live center.

click on the images to enlarge them.

the 3rd chart compares a new elgin cam and a worn redline cam.
The numbers seem close, but there is a difference.

 

Thanx Dennis,

I'm assuming that the lift is gross valve lift using theoretical rocker arm ratios. if it is lobe lift, that is a fairly aggressive grind for a non roller design.

 

Hello, great thread! If I had one of these engines, I think I would already be installing it. But, I do think I have the same Jeep steering in my model T & I would VERY MUCH like to see pictures of your steering set up. As well as, the part number of that Toyota non-power rack. I think it may solve alot of my problems! Is yours a factory tube axle or is it IFS? Thank you.

 

Sorry, I did not make that clear, It is at the end of the rocker arm not the actual lift at the lobe. I did measure it on the engine but was not able to get lift measurements which were consistent enough for me to have confidence in my measuring procedure.

the rocker arm ratio is 1.73 :1

 

It is a 1956 ford pickup I beam axle. had to mill the top flat to get a place to weld on the plate which holds the rack. There is no room under the car for photography.

To keep the rack out of sight I bolted it under a mounting plate welded transversely across the center of the axle. As I shortened the axle 2" to fit my chassis, the mounting plate also is a weld reinforcing plate. Probably a good idea as the axle was quite thick and that made welding it difficult. I specifically butted the axle ends up tight to prevent warping but doing this cuts way down on weld penetration. I would not have welded it without running a plate over the butt joint.

A tubular axle would be easier to weld as they are thinner but its round shape makes welding a plate on well more difficult.

As to part numbers, I don't even know the year of the car, I just ambled down a row of toyotas in the junkyard and pulled a few racks from smaller older cars which did not have all the hydraulics that power steering requires. Getting one about the right length to fit into your steering arms is critically important just measure it with a tape. Their length adjusts to set toe in, and this will get it to fit your car if it is close enough. Fitting the tapered hole in the steering arm is another important fit, it may be necessary to ream the holes if they are too small or the wrong taper.

You will need a bunch of universal joints so take a saw to the junkyard. It takes me about 20 minutes to cut one out of a car with a hacksaw. Their splined shafts need to be compatable with eachother and unfortunately most of them are not standardized, so be prepared to spend a day getting them and the needed splined shafting.

You must support the shafting in pillow blocks so it stays in place and the shaft runs must be designed so that movement of the axle does not bind or pull your steering apart or upset your steering (that is called "bump steer"). Splines will help take up movement but they must be clean and greased. A leather boot over them may help keepo the grit away.

Note that some racks are made to go ahead of an axle and others are made to be behind the axle. I chose rear steer racks and mounted it behind the axle...and found my car steered opposite from the way I wanted it to. So I bought gears and made a gearbox to reverse my steering. Works great. It would have been much easier to simply mount the rack atop the plate to reverse its steering, but as the plate was already welded in, The steering arms and the rack did not align as I wanted them to ( I was probably too fussy). If it happens to you also, just turn the rack over and that reverses its steering direction...but there must be a clear path from its splined shaft up toward your steering. Plan ahead, test it before you weld its plate in.

you can tell that this is not a bolt in proposition. If you just go out and buy parts it can be expensive I think the u joints are $75 each or so, I got ten to be sure I had enough and It cost me $20 for all of them including about 8 feet of splined stering shafting. I think the racks were $15 to $20.

You have to get enough parts so that at least some of them fit together.

 

If I did it over, I would weld in a special frame crossmember to carry the rack. It would bounce around less and would be more secure.

 

thanks for the response. It sounds like we had the same problem, I just don't understand totally how u fixed it without seeing pictures. Are u saying the splined shafts slide in& out of each other to shorten & extend the steering shaft as the axle goes up & down in its travel.

 

I drove enough farm tractors to see mower driveshafts moving around. It is like that. A shaft with supports at both ends can support a shaft with no other support. So my first shaft is supported at both ends the second shaft is indirectly supported by the closest bearing on adjacent shafts. It can slide through its pillow block that plus angle change possible in a ballbearing pillow block, makes it work.
Agricultural driveshafts have lengthy splined sections. I did not have that luxury so the horizontal and vertical displacement of the steering mechanism was taken up mainly by angular changes in the second shaft. A telescoping splined section in the second shaft
would solve design problems nicely.
spelling"you" as "u" irritates me. Please use don't use pidgin English.

 

Converting to rack and pinion steering frees up a lot of room in the engine bay as there are no tie rods etc. flailing around. So there are advantages beyond its light weight and quick positive steering. It is easy to forget how bad things were until we go back to them.

 

Can the 3.7 use BB or SB Ford solid or hydraulic? Does any one know?

 

As far as I know, SBF and BBF (429-460) are the same part number lifter. Some FE's use very different ones.
And yes that is exactly what the Mercruiser requires. They only ever came hydraulic from the factory, and honestly with the expansion and contraction of that big aluminum block I would think solid lifters wouldn't be smart because they would be out of adjustment for much of the warm up cycle. And you'd only consider solid lifters if you had the cam reground to suit, which to repeat, I think would be a bad idea.
I had my cam done by Lunati, as I was assured they had the most lift area of any "brand" of lobes (if you specifically requested their latest and greatest).