The elusive 224/3.7 MerCruiser banger

There is even more to it that you posted. The design of the core makes more difference than the material it is made of. Some cores witrh fewer fins cool better than ones with more. It's possible for a modern two row radiator to outcool a four row core. Modern aluminum radiators cool better than most copper ones.

In the eqarly '80s ford built a large and elaborate computer controlled and monitored "radiator dyno". A lot was learned abiut radiator design. Manufacturers from all over thew world were having radiators tested by Ford. Since that time other state of the art radiator testing installations have been constructed. Although based on good thinking, some of the things that were once believed have turned out to be incorrect.

 

http://www.facebook.com/photo.php?f...001696662588&type=1&pid=2813017&id=1409764870

Joe MAYABB's dirt late model modified 4 cal (mercruiser 3.7)

 

add BIG oil cooler ?

or thicker/tall radiator, or locate smaller secondary cooler ?

 

http://www.evanscooling.com/high-performance/

 

dennis,

I think your heating problems will go away when you put an aluminum head on your 470.

Dick

 

pretty much along my thinking,I changed from a 1 row radiator to a slightly larger [it is the biggest one that fits the car] 2 row radiator. Bought a 65 mustang aluminum one but could not get it in without cutting off its mouting flanges so didn't do that.

So with a doubled thickness and a big under nose air scoop it may be a lot better. [bigger than its original nose opening] and carefully ducted it up to the radiator. also changer to running just water with prestone rust inhibitor.

Will try it in a few hours.

 

you run much larger radiators than i can fit into this car so that willl help greatly.

It survived running with very little water so the Iron head is working for me.

the alloy head should be a great head tho.

 

It is about time for its oil change [#1 was at 20 minutes] now has 500 miles on it.
I am using purolater L3001 but although it has an anti drainback valve, the oil seems to drain back as there is engine noise on startup untill it has oil pressure.

Have I been using the wrong oil filter?

I found the following numbers on the internet, but do not have a whole lot of faith in them :
purolater L 24736
purolater L 34631
Hastings LF283
Hastings LF 279
wix 51061
fram ph30
napa 1061
mercury 0778864
mercury 60565


Any suggestions on which would not drain back? my manual lacks the oil filter spec [ guess I didn't xerox it]

 

50 years ago I was taught that air is in solution in water and it is driven out of solution as the temp increases accounting for the little bubbles. Those bubbles are seen even at low temps, so there may be two tiny bubble phenomena at work. With a temperature gradient in the fluid there could indeed also be microboiling.

I do not know anything about microboiling except that it would involve a change of state 540 calories per gram versus the much lower 1 calory per gram to increase that much water 1 degree C. However as it is just conducting heat away, that may not matter as the conducting is what matters.
Engine metal heat conducted to fluid, fluid to radiator metal and radiator metal heat to air. But I can see the microboiling as a possible kind of local heat transfer.

Pressurizing the system would repress boiling. And if gas pockets form in the engine, the metal area adjacent to them is no longer available for conducting much heat. Greater temperature differentials [ from higher temp systems and or special coolants] allow faster transfer of heat, [only a factor at the radiator though]. More radiator area also is of great value.

Special coolants which boil at higher temps would work like a pressurized system. They may have different rates[possibly lower] of heat transfer than water but that may be made up by the increased system temperature.

It depends on where the limiting poiint of the system is. If it is an undersized radiator, running at higher temps [more pressure or special coolant] may compensate for the problem.

 

Think those look good, and all probably cross-ref back to OEM merc somehow... What I found from trying to cross-ref was that if you start with Brand A , cross-ref to Brand B and C, then try to cross-ref back Brand A you may or may not get original part#, and possibly a few additional...

I beleive the Wix 51086/Napa 1086 is direct replacement



I went with
Wix 51060
Napa 1060

Mercruiser 3.7L Series (actual Marine filter)
51086
Height: 3.790
Anti-Drain Back Valve: Yes

51060
Height: 5.178
Anti-Drain Back Valve: Yes

http://www.breezeworks.net/cgi-bin/MBoard/forum/display_topic_threads.asp?ForumID=1&TopicID=1473

EDIT: looked up your Wix 51061/napa 1061, no mention of anti-drain valve
51061

 

It worked !

my engine is now running 70 to 80 degrees cooler than before at 60-70 mph.
It runs 160 degrees at that speed. Runs 20 degrees warmer at 30mph. these figures are at 75 degrees air temperature.

cooling system:
- toyota corolla water pump
- volvo crossflow radiator[out of the 1990's] turned onto its side becoming a downflow radiator
- plain water coolant
- MG midget header tank
- toyota overflow tank
- stock merc head and intake manifold with water connections fore and aft
- no thermostat (never needed one before but I may look for and add one)
- big airscoop under bumper
- small air dam over radiator

 

At present,I am using the mercruiser water filled intake manifold as a convenient pipe to run coolant forward, add vaporisation of fuel and possibly get a bit of cooling for the water.

Now that my radiator is so effective, manifold cooling is no longer needed and as the fuel can
boil at engine temperature causing carburetion problems.

[ the boiling point of gasoline varies somewhere between the extremes of 100 F and 400 F as it is a mixture of several volatile fluids.]


So, as a heated manifold may no longer necessary. I may route water forward in a pipe for cooler intake manifold temps.

 

They were numbers from other groups on the internet. The anti drainback valve is important to reduce engine wear.

 

I'm wondering about the appropriateness of my Mercruiser's timing advance springs.
Mine seem too stiff as all of the advance is not in by 2000 rpm. It finishes advancing at 3500 rpm. Is this normal for our engines? the advance specification at 2000rpm is 33 degrees in my clymer manual.

Any suggestions for weaker springs? I read that in one other engine a single spring is run. [ no spring of any kind on one weight]...I suppose one spring may be enough to pull both weights back in to the center so one of my springs used alone would be a bit soft.

I saw a statement that using two springs of different stiffness makes the curve in the advance curve. If so pulling the weak one out would be better. Or to stretch one spring.

What do you think?

 

Dennis,

Here is my latest aquisition for a possible installation on one of my 470s.

A Turbocharger from a 3.8 Buick V6 that provides 9 lbs of boost.

I like this setup because it is made to use a QuadraJet carb and was used on a 3.8 engine that is close enough to the same displacement.

They also did not use an intercooler.

They increased the Buick V6 from 125 hp to 200 hp without severely effection reliability.

If I can easily install it on the 470 I am sure that it will produce 300+ hp.

Thats about 1 hp per lb.

Anyway the only obvious disadvantage is to stealth so I might put this one into my 544 Volvo where it won't matter so much.

Dick

 

Does this pull in through carb to the compressor and then strait down to the intake?

 

stealth? With the tires turning to blue smoke?

It looks like a very nice setup. With that diameter it will spool up quickly.
I think it will do nicely. You may want a blower cam grind. I often have them in my engines [ just in case ].

Since you have an aftermarket head, there may be enough turbulence to be able to use low compression ratio pistons and have more room into which you can pump air & fuel. With the old iron head, I think it would be mandatory to zero deck the block to avoid pinging.

I'm very pleased with my engine. It turned out very well. Withstood thermal abuse well. Good power. a great improvement over its predecessor which took twice as much fuel and made less power, weighed 200 lbs more and was less reliable.

 

looks that way.

 

I don't think I've ever seen that setup.

 

That's the way it was. That is what Corviars did and that's what I did on my GMC. Very common

 

blow thru the carb or suck through the carb

 

The early Buick Grand National Turbos were the hot air pull through type.

They are not as efficient as Blow through with an intercooler.

The pull through turbo provides a lot of extra power with very little down side.

The most obviouse negative is the extra room they require.

The intercooler used on the blow through turbos provide more power but used more space and are even more complex.

I might also put one of the pull through turbos in a model A if I can use a cowl vent for cold air pickup.

compressing hot air that has already passed through the radiator just reduces the effectiveness of the turbo.

The problem being that between the heat transfer of the exhaust and the air being compressed the boost is partially negated by the heat expansion of the hot air.

9 lbs pressure cold air is better than 9 lbs pressure of hot air.

It's like finding that your engine performes better on a cold damp night at a low altitude than it does on a hot day in the mountains.

If I find that I get predetonation or learn that it is for sure desirable to have dished pistons I will use them.

I noticed that the grand national used dished pistons and it might be better to use them.


The heads that I use have the same 8.8 to 1 compression ratio as the cast iron 460 Ford heads used on the original Mercruiser boat engine.

Below is a picture that I pinched off the web that shows this setup on a Buick V6.

Notice that the exhaust pipe comming out of the front of the turbo is missing in the picture.

Dick

 

I'm running 9.5 to 1. Your 8.8 to 1 has more room to cram fuel/air mix into hence more power...same but more for a dished piston.

I'm wondering if passing through the compressor section would add enough swirl to reduce detonation on an engine with lots of deck clearance. If it is effective then the deeply dished pistons might not contribute much to detonation under boost..

I have no experience with the above but my engine does not knock even a little. So Randy and Dick Carrier gave me good advice. I'm glad I used it.

 

On a carbureted gasoline engine with a blow through turbo, it is necessary to use a suck through system or put the carb inside a pressure box and then there is the problem of fuel being blown backwards to the gas tank.

Many possible solutions present themselves:

1. add a fuel boost pressure pump and have a pressure regulator mounted inside the pressure box.
2. or have a pressurized little fuel holding tank near the carb [it'd have to have a backflow check valve and positive flow to the carb. Even a little tank inside the pressure box might work.
3 or pressurize the main tank, don't even consider that as I doubt they are strong enough for that.

The draw through system is much easier to do.

A fuel injected engine has none of these problems to deal with so it is the optimum choice fpr a boosted engine. The throttle body system from an early 90's Lumina would come close to working on a Mercruiser but it is designed for 125 hp. Perhaps more fuel pressure would raise its capacity enough.

It would be entertaining to make an injected mercruiser 470. Mine is doing so nicely with its little motocraft 2100 that I've not much incentive.

If you ran on methanol there'd be much less need for an intercooler because of its heat of vaporisation being so high..one solution for a carbed engine.

 

Draw through and blow through both have pluses and minuses. Draw through is easier, but even when the power valve is modified to be controlled by manifold pressure/vacuum, proper carb metering is harder to achieve.

 

The reason that I chose the Buick system is because Buick engineers solved the problems for an engine that is close to the displacement and operating rpm range of the Mercruiser.

I will do more diligence on the question of compression ratio and piston shape as I have seen pictures of Buick Grand National pistons and they were dished.

The port and valve sizes of the aluminum 460 heads (2.19 intake and 1.76 exhaust) should lend themselves to this turbo.

The only other limiting factor for me is whether or not I can get it all to fit in the cars that I want to install them in without altering the outside appearance of them.

I have tapered Quadrajet plates that I can place under the carbs to allow the engine to be installed on a slight slant.

This might help since I visualize the Buick setup turned 90 degrees and installed on the intake side of the engine with the carburator at the front and the turbo at the rear.

I will turn the exhaust manifold upside down.

If this shifts the exhaust manifold too much to yhe driver side I will offset the engine a little to the passenger side.

A stock looking Model A Ford or a 544 Volvo with a bulge in the hood is a dead giveaway that something powerful is under the hood.

That for me would spoil the fun.

Dick

 

Dick,
With the nice side mounts on this engine, it is quite easy to drop it well down between the frame rails if one wants to. [I did] I had a cramped engine compartment , but now it is roomy and I still have 6" to the ground.
I can't comment on your volvo, but the model A has a lot of room over the engine...you will have no trouble. My engine compartment is tiny but it was still possible to lower the car body 2.5" closer to the engine.

 

Dennis,

You were right about lowering the compression ratio.

After some due diligence on the web I found that the Buick turbo engines had 8 to 1 compression ratios.

And the pistons were indeed dished. SEE PICTURE BELOW

I have one 470 that was built .030 over and it has dished pistons.

I have heard that was a solution to the poor gasoline that became available for a few years.

I believe that the current premimum grade gas available today would have solved that problem.

At the time Mercruiser was suggesting that owners retard the timming 5 degrees to stop the preignition and heating problems the poor gas was causing.

We have to remember that these engines were pushing heavy boats at maximum rpm (4600 for the 170 hp and 4800 for the 190 hp engines) and doing it sometimes for hours at a time.

The Buick Grand National Turbos weighed over 3200 lbs and had 190 to 245 hp depending on the year.

The reason That I think the 470 will produce so much more power than the Buick V6 is that it starts with so much more.

The standard Buick 3.8 V6 produced 125 hp while the Mercruiser 3.7 boat engine produced 165 to 190 hp with a cast iron Ford head.

The after market performance head flows better than a 429 Cobra Jet head.

I will see if I can build one that stays together as well as the Buick.

These engines contrary to what many have said are very robust as proven by Sarge Nicols, Randy Dupre and others who have modified them to put out much more hp than I am trying to get out of them.

Dick
.

 

I don't think you can flip the manifold without covering the nearly vertical spark plugs. It might be possible to add a thick header flange and move it out enough to flip it, though. There is almost no quench on these heads so I stacked as Fel-Pro on a copper gasket to drop a half point. I need to get back to this project.

 

Phil,

You are right about turning the exhaust manifold over. It not only interferes with the spark plugs but off sets the ports.

I will either have to make a header for that purpose or make a U head pipe to feed the turbo.

I have figured out how to reduce the comp. ratio to 8.13 to 1 which is close enough to the Buicks 8 to 1.

Yeah you need to get back to this project.

I can use all of the help I can get.

Thanks, Dick