The elusive 224/3.7 MerCruiser banger

I saved too much weight on the alternator.
The kubota ones would be ample if there was just a battery ignition needing power.

 

Beck, I'm curious about your transmission also. Randy ran his motors up to 6800rpm for lots of power. Mine is usually chugs along around 2000rpm so I just want torque and an effective radiator.

I worked out a reasonably easy way to clean the pickup tube on the oil pump.
It works on the aluminum pumps as they have a center hole in the pickup screen.
Thread a lawnmower throttle cable housing completely through the tube as it is flexible enough to go around the bends. Pull dental floss back through the pickup tube with the throttle cable housing.
Tie a small rag to the dental floss so it is in the center of the floss. Pull the rag back and forth in the pickup tube with solvent but don't pull hard enough to break the floss or you will have to poke it out with the throttle cable housing that contains its wire for more stiffness. The hole in the screen is a screen bypass for when the screen is plugged. The hole is normally closed pressing against a strip of sheetmetal . Debris above the screen can be washed out or removed through the center hole with tweezers and pipe cleaners or q tips.

 

One other observation ..........

Electric radiator cooling fans are now a pretty normal thing to see on many factory cars, but you will never see a factory fitted electric water pump.

The wimpy little aftermarket water pumps being sold are just a gimmick, and just do not have the balls to raise internal engine water pressure to what is really required to work properly even on a stock engine.

If it worked, the vehicle manufacturers would have been onto it a long time ago.

 

Our reasons are not necessarily the same as theirs.
Pump have different failure modes:
Belt driven pumps must have the belt aligned, tensioned and intact.
Camshaft driven mercruiser pumps offer the problem of coolant leaking into engine oil.
Electrical pumps wires can break or short out.

Concerned about oil contamination, I changed to a belt driven pump, but the Mercruiser pump
is a nicer design with efficient, gracefully tapered impeller blades. Compared to it a Toyota Corolla water pump's stamped sheet metal impeller is crude and it does not appear to be capable of much force. If one wants more available power(temporarily) to drive the wheels, electrical pumps of course have an advantage. For comparison's sake, I'm going to build up one engine with a Mercruiser pump.
I'd love to find an inexpensive electrical pump to try in comparison with the others.

 

Have to agree, the original Mercruiser water pump is a nice pump, compared to most others.
But then, it has to be as its only turning over at half engine speed.
The original design intention of eliminating the fan belt was good, but by eliminating one potential failure point, the leaking seal problem arguably created something far worse.

 

I agree. Solving one problem created the problem of cross contaminating oil and antifreeze.

Cross contamination could be eliminated by leaving open the drain for the chamber between the seals. I was surprised at how quickly the camshaft can be grooved by the seal lips. Grease normally specified in the chamber to aid sealing could also seal the drain so I'd omit the grease and leave the drain plug out.

Impeller speed raises the question of power loss which should quadruple with speed doubling ( for this comparison to be valid, only the speed can change, everything else must remain unchanged).
I can't say that Toyota pumps are better, equal or worse than the Mercruiser pump. I can say that they , with some adaptation, can be made to fit and they do pump water.

 

BMW's come with electric water pumps. Have for years. Mercedes too.

 

In 2010 (off topic I know...sorry) BMW 3.0 Turbo 5-series cars (300hp) had electric water pumps. Replacements are around $250-$300. When you say "inexpensive" what does that mean?

 

Inexpensive is not $300. $30 is inexpensive to me, perhaps If you pull one yourself, one from a junkyard might go for that when the counterman is in a good mood.

When I go to a yard and make an offer, I try to be fair to them.
I lay what I think it is worth in cash on the counter next to the part.
If he picks up the money it is his and the part is mine.
If he smiles I put down too much money,
If he looks like he is sucking on dill pickles, I got a little discount.
If he shakes his head you have to lay down more money.
Then you have to show him you don't have any more money
He tells you nobody gets it that cheap but hands it to you anyway
The thing is to be fair and nice.
They have to pry money out of stingy people.
They want the money and I want the part so the odds of a discount are in your favor.

 

My oil pumps have taught me some things recently:

The aluminum pump is a newer version but not available. The cast iron one is still made but it is quite heavy. You can run a swab on a string down the aluminum pump's pickup tube as there is a center hole in its screen. If you do that you will probably "spring" the screen so it no longer acts as a valve and you will need to plug it's hole I cold not find a stopper that I trusted to stay in the hole but an expansion plug, inserted upside down and used as a simple stopper should say in place. its center hole has to be plugged, rtv silicone rubber to the rescue.

I could not find a new square cross section o ring for the pickup tube, but round cross section ones are available. I am trying one. It seemed a good idea to supplement it with high temperature rtv silicone rubber. The rtv mostly just created a mess which had to be removed. For the rtv to stick the surface must be oil free. The o ring by itself should be enough. You will need to have a new o ring as old ones get smashed out of shape. the O ring must be put into the channel it fits into if you assemble it on the tube, it will be at risk of having a chunk cut out of it if the tube is bolted up with its O ring squeezing plate at a slight angle.

The pump cover is supposed to have a thin gasket, you can make one out of 0.0045 kraft paper from a small bag. The gasket will give the proper end clearance for the rotating parts in the geo rotor pump. The cover plate may become scored if no gasket is used and parts rub. If it has been running and not scored its cover you can skip the gasket as aluminum pump clearance opens up when they come up to temperature but cast iron pumps don't do this.

The pump should be primed with oil through the pressure sender hole in the block. Filling it before bolting it to the block results in an oil puddle on the floor where you need to lay.

There is a definite sequence to follow to connect the pump and pickup tube : 1 bolt the pump to the block 2. bolt the tube to the block 3. work the o ring into place 4. slide the o ring pressure plate in place and tighten its socket head bolts. The top one is easy but the bottom one (on aluminum pumps) may take magic.
I will use very small vice grip pliers on it. RTV or a 0.020"thick paper gasket 3/4" ID and with 1" OD could back up o ring for a tighter squeeze on it. The area must first be squeaky clean for rtv..

Replacing an oil pump is a simple job, easy if the engine is out of your car. Working under a car with an engine dripping oil is unpleasant..

 

the larger image is a Felpro 520 SD

Felpro 520 SD headgaskets are for ford 460 engines and match our heads.
The blue lines in the illustration are beads of sealant around the coolant holes in the gasket.
This is a problem as open deck blocks have big openings around the cylinders not nice little coolant holes as in a ford block. So it looks as though the ford gasket will not seal as well in a Mercruiser engine as the critical place to seal our engines is the narrow ridge between the coolant passages and the engine's two lifter chambers.

Mercruiser head gaskets had beads of sealant where needed. I have recent gaskets from Mercruiser but they have changed in the last ten years and now lack any beads of sealant.

Randy had sealing issues with any head gasket but the old original Mercruiser gaskets.

Comparing the two gaskets, you can see that the coolant holes are larger toward the transmission end of the gasket as would be expected with the single coolant connection to the radiator. In this regard the sierra gasket looks odd unless it is upside down . You can buy single gaskets . the intake manifold flange can be drilled and tapped for a drain near the back of the block I posted on doing that long ago in this thread.

A Felpro 520 sd is shown here

 

Randy reported trying sealants on the critical ridge but said they all leaked.
I remember that one was silver paint, a traditional head gasket sealant 70 years ago. Locktite does make sealants to be applied by machine onto the surface of gaskets.
These problems make soldering in aluminum with tin to close the deck appear as the easier option if we can't get adequate head gaskets. Aluminum solders that melt below 500 F degrees are appropriate. They are about half as strong as aluminum. To get the metals to join, the aluminum oxide layer on the aluminum must be removed either chemically or by scrubbing it of when molten.]

I talked with Mahle tech support today, they are impressive (better than anyone else). Although there are no gaskets with sealant beads in the right spots, they are really interested, provided excellent advice and will even read our posts on this group.

 

Sorry for the major delay in responding to this. I haven't been watching this thread as much as I should.
The transmission is a Doug Nash 2 speed. They were made to be used in Modified dirt cars. There were a couple of gearsets available inside the transmission with high being at or near 1:1. Low could be just very little under high or as low as 1:1.6. Low gearsets are available but very costly. It does have a reverse. On the rear of the transmission is a cover that accepts quick change gears. That allows anywhere from a 1.6 overdrive to a 1.6 underdrive of the internal gearing. These gearboxes are obsolete and difficult to find. Does anyone have one they want to sell???

I weighed it without rear fenders, seat, radiator etc. and it was looking like I would make it, but I have been constantly adding more stuff, so I am again concerned.

I am running an aluminum housing 8" Ford rear axle. I made the housing starting from an IRS Explorer center section. I put aluminum axle tubes and bearing cups onto it. I am afraid I am going to bend it.

 

Are the QC gears 6 or 10 spline, or something else?

What diameter and wall thickness are the axle tubes. I built a Quickchange for a swamp buggy years ago. The owner bent 3" o.d. X 1/4" wall steel axle tubes. They were pretty long, but I didn't think he could get enough traction to bend them. There must be a terrific amount of torque reaction generated by those paddle tires. I'm thinking you have a similar situation.
If you do have problems, I think I may have a lighter and stronger solution.

 

You can also install a brace to the rear of the housing. It's done to most 9" inch rears in racing. It stiffens the housings tremendously!

 

My axle tubes are 3" od x 1/4' wall aluminum.
My frame is only 18" wide. The frame is 1" square tubing. There are mounting plates welded to the tubes at the inside of the frame (16" between them). That doesn't let enough room to put a gusset.
The axle is narrow enough that I only have 1/4" clearance between the tire and frame.

 

Beck, Was bending ever an issue for you? It is hard to fix problems you don't have. You have enough effort into what you now have so I'd test it to see if it is ok. What you wrote about continued changes adding excessive weight rings true.
Your quest for gear sets reminded me that the whole problem could be bypassed with the engine mounted transversely in the chassis driving a layshaft with sprockets and chains to a solid rear axle. It would be light, simple, cheap and more efficient than gears so you would gain wheel horsepower.

 

dennis g , I do plan to run my rear axle as it as it is and see what happens. I will be nervous on the 1st run.

The boat motor is to wide to put in transversely. My current frame is only 18" wide.
Transverse mounting to a chain drive makes clutch mounting difficult. It would probably require a jack shaft to get enough gear reduction. There is drag in the chain and the bearings required for the shafting, possibly more than inline mounting. Chain drive would rule out steering brakes since the rear axle would be solid shaft.

I had looked at inline mounting with chain drive to an offset drive shaft. That would have eliminated the transmission. Gear selection would have been done by changing sprockets. The rear axle gearing would have eliminated the need for the jack shaft. One of the big drawbacks of the chain drive is the lack of reverse. Pushing these things backward is a pain. I currently have to do that with both of my motorcycle powered tractors.

 

Chain drives are around 97%to 98% efficient
Hypoid gears 85% and up into the 90's.

I run small motorcycles with two rear sprockets. I just change change length and use the other sprocket.

Yes, transverse engines have to be short.

Reversing on some heavy motorcycles is by using an electric motor. Heat buildup in the motor is a limit on how much one can back up.

I was told that a differential can be used with a chain driving part of it. there would be dirt in the gears though.

You use an eight inch rear end it is enough for a small block ford and they are equivalent to a Mercruiser in torque.


The chain stuff would be for a different build

 

How many of you are using head gaskets with no sealant beads?
I've always used gaskets with beads so I don't know if plain gaskets work. As the good gaskets are no longer available we may need to order a batch of special gaskets made.

Let me know please.

 

I have built 2 different style chain drive differentials that are sealed, at least somewhat. One is an 8" Ford differential with a homebuilt cover on the gearing. The other uses the planetary shell and gearing from a FWD car. I haven't used the 8" one yet. The one built from the FWD parts has a controlled leak. I didn't use oil seals. I depend on the sealed bearings to hold the oil. I have to add lube at every event and put a pan under it to catch the leakage in the trailer. On a plus side, during operation the leak goes on the chain keeping it lubed, and if it is leaking in the trailer it didn't run out of oil. Having no suspension enables the differential parts get solidly mounted.

 

The head gasket conversation has me worried. When I initially put my motor together I was planning to run a dry block. Using methanol as fuel keeps thing a little cooler. Since then I have decided to use gasoline. I have added a cooling system. If I remember I put a regular BBF head gasket on mine, so it is likely to leak water.

 

Has anyone on here finished a car with one in it yet

 

I have talked with felpro, locktite (Henkel),Mahle and Cometic
no one still makes a gasket with a sealant bead where it needs to be for the Mercruiser engine. Cometic makes a Ford 460 gasket with an embossed raised surface across the entire gasket it is #C5666-040. [The number differs with bore ] It requires a very smooth engine surfaces to seal. Cometic does not make fiber head gaskets, only steel ones.
As to the sealant bead that worked on mercruiser engines Cometic told me that the bead was applied with silk-screening in which the appropriate thickness was built up by multiple silk-screenings. The sealant bead material was a complex mixture which was liquid when applied but which then semi-hardened on the gasket capable of deforming under pressure and softens under heat to allow for movement so the gasket will not tear. apart.

 

Yes, there are a number of cars running this engine. I run one in a street rod that I completed several years ago. I continue to work on my 4th engine in the car. They are not an engine that you just bolt in the car and forget. You can see others by looking back through the posts.

 

These engines perform quite well. Randy Dupree ran them in a land speed car that went 186 mph before a door blew off of his car, he reported that it was not near its maximum at that point. He ran his modified engines up to about 6800 rpm. He made long stroke and short stroke versions of the engine. There is a video back some pages showing this engine in another man's fast quarter mile car.

 

The ford gasket is all that is available.We need to check on how the boat guys are doing . Big Chief would know.

 

this is the commetic embossed gasket I can see that some of the embossed part is in the right place but I can't tell from the photo if it runs continuously from ed to end as it needs to.

 

you could run an SCE copper gasket. They are available separately.

 

I surfaced the block with the engine in my car so I can't get as nice a finish as is needed for steel gaskets and perhaps copper also. Your suggestion is a worthy one and I will follow up on it with a call to SCE to check on smoothness requirements etc. Copper gaskets can be reused after annealing them.
[Heat to about 500F and plunge into tap water. Those instruction were in a Yamaha dealer shop manual. ]