The elusive 224/3.7 MerCruiser banger

Flats added to the sides would be flats machined at the spot where one sleeve contacted the next one to allow the bores to be centered/aligned over the crank throws, as the sleeves were too large in diameter to maintain the proper bore spacing. The Darton article I mentioned earlier also ran into this problem : they solved it quite cleverly : after installing the first & third sleeves, then doing the boring for the second & forth the problem was automatically solved by the interference bore into the already installed sleeve to 'clear' the incoming sleeve, & insuring a "snug" fit at the same time. No need to calculate & add an extra machine process if this method is used. THE KISS PRINCIPLE WORKS!!

 

The flaw I see in this method is all of the material is removed from 2 of the sleeves. This will make the wall thickness of those 2 sleeves much thinner at the boring locations. The sleeve on #3 would have the clearance bore done to both sides. A lot would depend on how much oversize the OD of the sleeve was, and how big of a bore was intended. If I recall correctly, the off the shelf sleeves from LA Sleeve the OD was quite a bit oversized.

If flats were put on the sleeves, #1 and #4 would need them only on 1 side. #2 and #3 would get them on both sides. A flaw with both of these methods is that the sleeves are not all 1 piece like the "cast in" original setup. Even though they would be pressed in together, minor movement would still be possible.

Sleeving is a great idea in theory, but the cost is prohibitive for me.

Completely machining out the old sleeves and installing new ones also requires closing the top deck of the block because the sleeves need a seating surface. There have been a couple ways to do that covered before.

 

As stated before : "closing" the "open" deck would lend upper end support to the sleeves & minimize "movement", which is already partially controlled by the 'cylinder head/head gasket/block' torqued 'crush'. In the Darton story the amt of metal removed in the secondary boring process was not enough to seriously affect the sleeve strength, but was enough to help stabilize the alignment. Yes, the sleeves would need to be selected so as not to need much undercutting for installation. I'm not presenting this as a necessity, only as another possibility to expand the range of alternative solutions available, & I agree : But it's only 4 cylinders, NOT 8, so it is a little cheaper.

 

Did you get noticeably pinging?

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Any updates on your cooling system? All still working great?

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Scott it pinged even when idling unless I pulled the spark setting back to 28 degrees (with the Elgin camshaft).
The Elgin camshaft was only useful as a core. but that was ok as I needed a core for grinding and they have been difficult to find. A thicker radiator licked the cooling problems that I had been having. I use Volvo crossflow radiators rotated 90 degrees to make an old style down flow radiator.

 

All good info. Thanks

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If the cylinders were far enough apart it would work well. however Mercruiser cylinders are close so what they did would leave very little material in the cylinder wall. If the adjacent sleeves were brazed together the lost strength would be regained but I seriously doubt that any reasonable amount of machining would get them to fit the crankcase without leaking.

I burst a cylinder 2 years ago so cylinder strength is of paramount importance to me. The cylinder burst keeping the rod from bending. Analogous to an expensive transistor blowing to save a cheap fuse.

 

Did the detonation cause the split cylinder?

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Curious to see if anyone has a Merc3.7 block (no worry about bore condition) and a usable crankshaft available. No need for a head, intake, exhaust, etc. Just block w/no broken bits and a usable crank.

I'm in Albuquerque, NM. Thanks much.

 

Esslinger posted this on Facebook. Looks like they can do sleeving in a die cast block, this one an Ecoboost.

 

no it split due to hydrolocking. It also detonated badly after a camshaft change with more than 28 degrees ignition advance and a rod bearing knock developed. On teardown the bearing was down into its copper layer.
This all happened after its camshaft change. I can see how the cam change led to knocking as cranking pressure changed from 165 to 210 but can knocking destroy a rod bearing?

 

Those knocks you hear are equivalent to hitting the piston down the hole with a 20 pound sledge hammer. Yes that can destroy a rod bearing.

 

I asked a local starter shop if they could get a lighter starter starter for my 470. They checked and called later saying "Sit down for this. The good news is that gear reduction starters are made for your engine. The bad news is that they are $450 and weighs half as much as the 20 lb Merc starter". I replied that i'd pass on it for now.
Just checked Ebay saw a new 9 lb geared starter for $330
I can save much more weight than that by replacing my car's battery with supercapacitors for starting.

 

International scout gear reduction.

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I found that my most recent Mercruiser 470 engine has rod bearings about 1/4 narrower than the caps. It does not seem right to me. The bearings are Mercruiser bearings and have the name Mercruiser stamped into them. Has anyone run into this?

 

bearings about 1/4 narrower than the caps. It does not seem right to me. The bearings are Mercruiser bearings and have the name Mercruiser stamped into them.

I have not run into this,, but I would think that the radius at the fillet would be larger and the narrower bearing would be for the clearance.

 

It left so much room for fillets (3/16") per side that I just ordered new bearings

 

the new bearings were the same size as those I had.

 

IADR’s not posted anything for a bit, but I wonder if the Jeep-to-Mustang T-5 bellhousing he writes of is this'n:

https://www.kaiserwillys.com/catego...ousing-fits-80-81-cj-sr4-4-speed-transmission

If so, kaiserwillys.com Jeep parts catalogs them, thus ending that particular bellhusing’s bid for extreme world-class unobtainium rarity, kinda like Pluto's bid for full planet status. Stupid asteroid planet wannabe.

Ed

 

I just stumbled across this electric water pump used in BMWs. I wonder if they would work for our 3.7s
http://www.ebay.com/itm/Electric-En...d=132080609405&_trksid=p2047675.c100005.m1851

 

It claims to work for a 328i and a 328i has more power than our engines so it should be ok.

 

Which direction do the rods go into our blocks. There is a pad (balancing?) on the little end. Does it to toward or away from the camshaft?
I have a mock up motor in my project that I could pull the pan off of to look if needed. I was hoping someone either had the answer or had one apart to that stage to look.
Looking through the fuel pump hole on my mock up motor I cannot see up into the piston skirt. I can see number stamped rods, so I know it has been rebuilt prior.
I finally have my parts to complete a short block. I need head studs yet to put the head on.

 

the numbers on the rods face the camshaft.

 

Head studs...class act. How much will they cost? I always used bolts ( free) but would prefer studs.

 

The numbers I mentioned were hand stamped by a previous rebuilder. They could have been stamped on either side at that time. There are no factory cast numbers on the rod sides.

What you said does make sense though. While looking through the fuel pump hole in the side of the block, I am looking in through the cam side of the block. I can see the hand stamped numbers on those rods.

 

Another project has appeared, delaying my motor build. My pistons have arrived.
I have some unknowns about the head studs.
Does the threaded end in the block need to be longer than the BBF ones since our blocks are aluminum?
The studs I use will need to be longer because my racing head is taller than a stock head.
I will need to search to find studs from a different application that have the dimensions I need. I doubt ARP has an easy way to do that.
OR - Since I am using a Trick Flow A460 head. Trick Flow sells a stud kit for those for $320. If they need to be longer for the aluminum block they won't work. There would be enough studs to do 2 Mercruiser heads. There would still be all the intake bolts unused. Since I only have one of these heads, this sounds like a waste of money. Trick Flow will not sell a partial set.

 

If you did need liners, go for broke. Here is one with 4.6" bore. http://www.dragzine.com/news/homegrown-horsepower-four-cylinder-mercruiser-in-a-dragster/

 

Aren't Mercruiser and BBF headbolts the same? So your studs should at least match the bolts.
There is something to be learned from Volkswagen cylinder stud problems. Fat studs broke. Slender necked-down studs stretched and did not break although they do fatigue, are stressed into yield and thus are a single use fastener.
Aluminum can pull up around a stud as aluminum is ductile. Using Helicoils on studs engages more aluminum, resulting in less stress on aluminum around the stud.

Shear strength of die cast aluminum is commonly given as 25 to 26 thousand psi. Gray cast iron shear strength varies from 26 to 88.5 thousand lbs per square inch.
As to the threaded length on the fastener, it is claimed that the load is such that the first few threads strip out and then failure proceeds down the fastener like falling dominos .
I leave the conclusion up to you as I'm no expert.