The elusive 224/3.7 MerCruiser banger

you may be asked for the outer dimensions of the aluminum plate plug i combined 27 measurements of the openings in three blocks it is 5.6907 inches with a standard deviation of 0.00073 inch (so the numbers are good). the blocks do vary but not a lot. Individually, my blocks water jackets average 5.6936 inches,5.6891 inches and 5.6869 inches across.
the length of the plug is close to 20.5 inches (no statistics, and a single worse measurement)

 

I tried to cut a 1/4 plate today off my drawing, my plasma did ok on the 1/8" thick stuff but not the 1/4" I know my router would make a nice part but would have to change my whole table over already have too many projects in the works right now. If I get a chance tomorrow I will swing by my local metal supply / fab shop and see if I can get a few pieces cut. Just out in the garage and looking at this problem and wonder if we are looking at it all wrong, what about filling the lifter openings instead of the water jackets then just cut slots for the push rods and a few oil drain back holes? It would be a simple rectangle and require a lot less welding.

 

The task is to keep water out of the engine oil. If oil can drain down around pushrods, so would water that gets into the area.
However if the lifter gallery cover had a raised area surrounding the pushrod slot or silicone rubber boots on the pushrods , water could be diverted away and drained out an opening but oil would also go out the drain. The lifter gallery cover would have to be bolted in place so lifters and cams could be changed.

Other options:
1. Use an overhead cam head and there would be no pushrods to deal with. Too extensive a change to be practical.

2. Widen the block's sealing surface adjacent to the lifter gallery.
Aluminum could be added to on both sides but lifter diameter strongly limits width increase on the gallery side.

The water jacket side could have a lot of material added to it. I have epoxy glued cylinder support blocks in here on one of my engines and they remain in place after running the engine an hour even though it got really hot without enough water in it.
My filler blocks are 1/2 inch tall and were hand fitted between the cylinder and the engine block. [the epoxy is 300 degree rated epoxy]
Since epoxy and aluminum have different coefficents of thermal expansion, I kept the epoxy layer thin so dimension changes due to different materials expanding are minimal. I think i posted a photo of them in place.

3. We could just pour Devcon into the top of the water jacket over the top of baking soda and not bother with adding aluminum.
As Devcon would reduce upper cylinder heat loss it would be good to use an aluminum head to carry heat away from the hot upper part of cylinders. As cylinders increase in diameter, the heat retention problem becomes worse. I've no idea of how much of a problem it is, but our cylinders are large.

4. I sent my drawing out for conversion to dxf and should have it back in a day. I will post the file if it looks ok.

 

You are correct, the photo is the inside of the transom, I built the boat. The pump is a two stage Kodiak jet with scott impellors.
Thanks again for all your info on this engine, they are very tough motors ! I have had very little trouble, only self inflicted stuff !

 

most trouble is self inflicted...I speak from experience .

 

For $5 a company [Vectordesign.us ] cleaned up my drawing and they will convert it to dxf. It is pretty, but they got carried away filling in gaps and this will be taken care of They are responsive and take visa.
They do a lot of work for their fee.

 

I found a couple more places to find info on facebook. You have to ask to join the group and answer a couple 470 related questions to be accepted as a member, which I did.
Mercruiser 470 3.7l big 4 owners
Mercruiser 470 Racing Group

It appears there is some experience there with the head insert.

 

some information on cleaning aluminum for welding

 

the part about needing to remove aluminum back 1/8 of an inch from a laser cut came as a shock. 3000 and 5000 series aluminum alloys are not required to do this but most of the 5000 alloys can't be used.

aluminum alloys we can use for soldering with out cutting back 1/8"
best ones:
1100
1200
1235
1350
3003
next best ones:
3004
5357

 

It took a day for the racing site to approve me.
There is much more information here than there, but every little bit helps.
A year ago one of those guys posted a photo of a block insert, then a few months later the block with the insert TIG welded in, then later the block back from the machine shop.
It seems they like 3/8" plate for the insert.
I messaged the guy asking how it was cut and he responded that he cut his with his band saw. Which according to dennis g's post above isn't recommended.
We wouldn't need any "fancy" dfx file to hand cut it would we?

 

I have made patterns that will work for hand cutting. a scroll saw could do the center cut but only if the plate is held down firmly. Or a big hole saw and a coarse file to finish it. or a jigsaw with a roller supporting the back of the blade and then file to fit.
I'd definately make a trial pattern first on thin sheet metal to be sure the fit is not too loose.
Vector is preparing a dxf file but I don't have it yet. Cad/cam is a pain in the but.
the above information on welding is from Miller [the big list] and from a laser cleaning company [the small list]. As the fill plate is not structural, some aspects may matter less. 3/8" thick will bleed heat away better[a good thing]. Ideally, the plate and the engine should heat at equal rates so one part does not run away on the floor before the other part gets up to temperature. That is the concerning thing about joining aluminum by melting it together. That and knowing that the oxide melts at a higher temp than the base metal. tig welding is going to heat only a small area ...I can not predict what the result of that will be regarding warping.

 

I was at one of the places I buy metal today. It appears they don't have 5/16" thick aluminum. They go from 1/4" to 3/8". They did have some "drops" that were big enough to do the insert. If I recall correctly it was priced at $6 a pound. My fear with a "drop" is that it truly was dropped or bent in some way.

 

Tom.
I'm thinking that we will likely have to straighten any plates after they are cut, especially with any heat. By the time the plate gets installed it will likely have to be surfaced with the block.

And yes that was me on the FB site. I believe that one of the Moderators is Chris Nichols. He and his Dad (Sarge) built a Bad Boy dragster with a 3.7. He seems to be in the know with who's got what and done what. Some of those guys are REALLY over the top. I'd like to end up somewhere in between.

 

List of Temperature Resistance:
200 degrees Farenheit :
Devcon 10240
Devcon 11320
Locktite 23615

225F :
locktite 209827
locktite 3472
jb weld 8271 kwikweld
250F :
Devcon 10210 plastic steel
Devcon 10610 aluminum putty
Devcon 10710 pourable aluminum liquid
Devcon 10720 aluminum liquid for potting and molds
Devcon 10780 fast metal putty
Devcon 11800 underwater putty
Devcon magic bond [withstands water]
JB weld 8277 water weld putty
Locktite 209822 fixmaster steel

300F :
JB weld 8276 kwikweld
JB weld 8281 steel epoxy
JB weld 826582 (500F claimed)

350 F
Lab metal not an epoxy, this one should be thinned $20/lb
Devcon titanium $120/lb

500F:
original jb weld 8280
jb weld 862582

1000F high heat lab metal
2400F extreme heat jb weld

[some of these figures stretch my ability to believe in them ]
It appears that temperature rating correlates with the manufacturer
As I've run my motor at 265 F anything under 300f is useless
note: claims for continuous heat are lower than for short exposure heat
note : If the cured material is wet, temperature resistance is less

 

note: As I've run my motor at 265 F anything under 300f is useless
-----------------------------------------------------------------------------
250F :
Devcon 10210 plastic steel
Devcon 10710 pourable aluminum liquid
Devcon 10720 aluminum liquid for potting and molds
Devcon Magic Bond
Locktite 209822 fixmaster steel
---------------------------------------------------------------------------
300F :
JB weld 8276 kwikweld
JB weld 8281 steel epoxy
JB weld 826582 (500F claimed)
----------------------------------------------------------------------------
350 F
Lab metal not an epoxy, may have to be applied in layers,this one should be thinned $20/lb

Devcon titanium $120/lb

the lowest melting aluminum solder 350
----------------------------------------------------------------------------
500F:
original jb weld 8280
jb weld 862582
------------------------------------------------------------------------------
400F-700F common aluminum solders
700F and up aluminum brazing
note: continuous heat rating is much lower than short term heat resistance
note : If the cured material is wet, temperature resistance is less[/QUOTE]

 

Don't forget that aluminum alloys melt between
865F and 1240F with no warning
pure aluminum melts at 1218F with no warning

 

I'm going to re-ask a question I ask here back in 2015. How is everyone mounting their oil pump? There is a Mercruiser tool to align the pump with the distributor shaft. It is no longer available. dennis g posted back in 2010 that he shimmed the bolts to center them in the oil pump housing. That centers the pump with the bolts but possibly not the distributor shaft. Does anyone have one of the tools? If so a photo would be nice. I'd like to make something like the Mercruiser tool.

 

Beck,
Don't know if you've seen this.

https://forums.iboats.com/threads/oil-pump-alignment.345111/

Doesn't look too bad to make.

 

I had read that. I cannot open the photos since I'm not a member. I don't like the idea of the white plastic. I machined some last week for chain idlers. It sure machines easily but it isn't as rigid as a metal part would be. I had considered trying to design my own similar to that. I would make a sleeve that fits into the block like the distributor. I'd put an oversized steel shaft in it to reduce flex. It could be nearly the diameter of the cam gear, since my cam is in. I would reduce the shaft where it went into the pump. I wouldn't put a hex on it, just a round end that was the diameter of the flats of the hex.
Do you think that may work?

 

As I was reading that write-up, I was thinking the same thing. Maybe just a mock distributor housing with a round protrusion at the end.
What is the size of the hex shaft?

Is there a way to dowel the pump once it is located?

 

The shaft is 5/16" hex. A cut off allen wrench could be used on the pump end if a hex was desired.
It has been a while since I looked at the bottom end, so I don't know if the pump could be pinned. I don't know that I would dowel pin it anyway. I doubt all the pumps were machined exactly alike. The next pump may not line up using the dowel, and you would have to transfer the dowel location to the next pump.

 

Distributor. My hex shaft has some play where it attaches at the top.

 

Just to document the thread for future reference:

 

The merc distributors that I have worked with have some play at the top of the hexagonal shaft. two slugs of metal or even brazed on washers well apart, ground to appropriate diameters of the distributor would center a hex shaft in a center location for mounting the oil pump.

 

It will work. You could use 1/8" pipe for most of it, build it out with two rings fitting on the pipe, 1 above and 1 below the camshaft location.

 

Have you got the converted file yet?

 

not yet.. I may have to offer them another $5 to do it. Will try that tomorrow .

 

I checked the price of aluminum for one 7" x 22" x 1/4" plate of 6061 2 lbs
[3/8" would be 50% more as it weighs 3 lbs]

metals supermarket quoted $25 for 2 lbs
My local plasma cutter $15 [2 lbs] and he said it would be cheaper If I brought my own metal to him.
One of you was quoted $6 per lb or $12 for 2 lbs
the local scrap metal outfit said $ 7.70 for 2 lbs but they had no metal thick enough
the regional metal outfit said their remnants 2 weeks ago were too short I have to check back checked back, 3/8" remnants were too narrow at 5"
but they charge $1.85 per lb

 

All of the drops that I have bought have been flawless the only problem I have with them is that a bum lets himself into my storage and helps himself to anything that sparkles.

 

thinking about head water flow;
Mercruiser used their own head gasket with a Ford head modified to have a single front water outlet.
As a Ford head on a Ford block has water outlets on the side of the head, water flow through the gasket should be radically diferent. {I've not checked a Ford gasket}

Water holes in the Mercruiser gasket are tiny on the right side and very small on the left near its front to force water to flow to the rear of the head for proper cooling.
I anticipate that the Ford gasket would not be this way for proper cooling due to its side outlets. So I would expect to see larger holes on the exhaust side but little difference fore and aft.

So to use the gasket which will give your engine proper coolant flow, you may need to modify its coolant holes to match what the head needs.

My first engine was sensitive to radiator size, perhaps as I used a Ford head (side water outlets) and a Mercruiser gasket . Knowing the Mercruiser gaskets should seal better, I used them but did not consider coolant flow.

Engine temperature is influenced by several things: Ignition timing, cam profile, radiator size, fan air flow, coolant flow pattern, water pump flow, the thermostat, load, throttle position and the fuel to air ratio.