The elusive 224/3.7 MerCruiser banger

Damn! I want one of these! You can't post too many pictures or give too much info.



Fixed it for you.

 

It should be a great first car. I am only 15 years old. My grandpa and I have been collecting parts since I was twelve. We bought the frame rails and I welded the boxing plates and crossmembers in. But the engine should make about 400 horsepower but we are gonna put a procharger/vortec supercharger on it. That should put it around 500. Keep in mind it is a glass body car and an all aluminum motor. It should only weigh about 1800 pounds. It will have a good weight to power ratio

 

Does anyone with an offset ground crank stroker care to share some figures?

Boss9 Brian, I see you are using 6.8" rods. I am not qualified to do any of this but my figures are leading me toward a bbc 6.385" rod. Doesn't your long rod move the pin pretty high on the piston? Using the shorter rod would allow stock pistons to be used with rhe right offset grind. Are you just trying to improve the rod stroke ratio, or is there a replacement piston that is nearly right for this combo?

I am going to have to have custom pistons made also. My pistons require a thicker top because of my intended turbo use. There aren't any shelf pistons for the A460 heads with a bore this small. For the price of rods and an offset grind on the crank I can add some more cubes.

Any and all input is appreciated. Some of this is over my head.

 

If you offset grind the crank to a 4 inch stroke total the journal size will be a 2.200 big block chevy size then by using the bbc 6.8 rod you can use a 460 stroker piston that has a 1.455 compression distance. This will give you a 1.7 rod ratio. What stroke do you plan on running?

 

I did my calculations several months ago, using the 6.385 BBC rod length and the stock piston. I didn't look at any of the stroker piston compression heights. I don't remember what stroke I had come up with. At the time I was looking at letting the piston down in the hole a bit to reduce my compression. I have since learned that is bad for flame travel durring combustion. I will have to revisit this looking at your rod length.
Thanks for the input.

 

No problem

 

If you plan on going the turbo route I would suggest turning the block into a closed deck. We had a 1/4" thick piece of aluminum cut to fit into the water jacket around the cylinders. We are going to weld the plate in then decl the top of the block to smooth it. The cylinders in these motors aren't really supported at the top. Then later on you just cut the water holes in the plate and you have a closed deck block with extra strength on the top. It is really just an extra safety assurance but it's creative to. Here is some pics of mine

 

Boss9 Brian : Great idea to reinforce the top of the block!! This would allow the use of Dalton(or similar) sleeves for more displacement! beck : To expand your choices I suggest looking at available piston dia/compression height /pin dia combos to assist in determining available/useable rod lengths & crank throw diameters(how much off-set can be ground into the crank?) from other brands. For example ;Rat motor flattop pistons(4.5"/pick your compression height for the rod length/ block deck height)/ Rods to match the pistons & off-set ground crank to match(you'd use Chevrolet wrist pins 'cause the parts don't care) Applying both Boss9 Brian & beck's concepts I could see a useable 270"motor without too many exotic parts. Outside the box can be fun!! LOL!!

 

There us a guy that built a 274" motor and uses it in his dragster. It has a 4.600 bore with a trickflow A460 head. It's bad ass. Currently welding the deck plate right now though. I will post a pic after the welding process

 

I will stay tuned here,,, I love a good Frankenstein motor with lots of mixed matched parts. Starts the creative juices flowing.

 

Now to go WAY outside the box : IF we can 'close-deck' the block, what's stopping us from adding a , say 1", spacer plate to the block before boring for oversize sleeves so that we can have a 'long-rod/ long-stroke' combination? As long as we're welding aluminum & redrilling the water holes why not? We'd need appropriately longer pushrods & head studs of course. Maybe add one of John Kaase's heads just 'because' (with some HUGE injectors almost mandatory!) All kinds of possibilities, aren't there? Sounds like it could even almost be reliable enough for a street motor?

 

YES. This sounds like a great idea. As of now we are thinking about doing a different closed deck block with a bigger bore. But I don't know. I feel like the A460 still as better performance from what I have seen. The boss nine head may not be the best decision. We chose it because it is different and looks awesome.

 

YES. This sounds like a great idea. As of now we are thinking about doing a different closed deck block with a bigger bore. But I don't know. I feel like the A460 still as better performance from what I have seen. The boss nine head may not be the best decision. We chose it because it is different and looks awesome.

 

Boss9 Brian : I like the way you think!! If you haven't looked up Kaase Racing, check your pulse, then go drool over his head/motor work. He's the guy that developed the Boss 429 head for Ford, or so he says, & I have no reason to doubt him.

 

Trust me, I have read a lot about it. I have one sitting on my bench right now. I am using it on my mercruiser engine. My favorite things are the MASSIVE valves, long exhaust rocker arms, and the width of it. The top of the head is two inches wider than the block. The only thing I wish was different is if the exhaust ports were round. They aren't so you are almost forced in to buying one of his header flanges. But I can't complain because I am still in love with my lil banger. I mean it's pretty cool for just a four cylinder I guess (;

 

Trust me, I have read a lot about it. I have one sitting on my bench right now. I am using it on my mercruiser engine. My favorite things are the MASSIVE valves, long exhaust rocker arms, and the width of it. The top of the head is two inches wider than the block. The only thing I wish was different is if the exhaust ports were round. They aren't so you are almost forced in to buying one of his header flanges. But I can't complain because I am still in love with my lil banger. I mean it's pretty cool for just a four cylinder I guess (;

 

Boss9 Brian : What I meant was to check out what he's done with those heads since he parted ways with Ford : he's developed them way beyond where he was with Ford( as in relocated valves/chamber shape/plug locations/etc), as well as building complete engines(not what we're interested in, but that's where the heads got the development, so It's all good!) His port flow chart numbers/engine output numbers are mind-bending!

 

drtrcrV-8 : Yeah. We just got our flow numbers. We barely need any lift in the cam because of the numbers the head flows. This is gonna be really interesting but thanks to closed loop efi it will work great lol

 

One good thing about high flow at low lift, especially on a street engine : lower lift cams usually put a lot less stress on the valve train & the engines 'live' longer (or at least don't have the cam/valve-train failures of their radical 'cousins')! Also tends to give a more part-throttle responsive(smoother) engine. I'm glad to see more development going on with this engine, as I've always liked big 4cyl engines, especially 'cause on the street they can be hidden under 'stock' sheet metal, or go into otherwise tight engine compartments & still have enough room to work on them!

 

My banger is going into a little 32 ford and its my daily driver. I really want sheet metal sides because I don't want people screwing around with it. But I completely agree. The size of these engines externally and internally is amazing. I would definitely do another project with one. Maybe a little sleeper bug and ditch the back seats (;

 

For a street motor I would not stroke one of these. They shake pretty bad at their current stroke. Adding to it will just make it worse.
That 274" drag motor shakes the whole car apart. They cannot keep any bolts tight.

 

Yeah but the also lightened the crank by quite a bit. When you lighten a crank you lose the balance. I stroked mine to 4.000" inch and lightened it by about 5 pounds. I haven't heard or seen one run in person. We are building to what we either knows works, looks cool, or just want to try something. We got the whole engine for free. As of right now the only money we have in the motor is the deck plate and bolt on stuff. It is truly a trial and error and educated predictions for us.

 

You guys have probably said it before but what are your 3.7's going in to? Just curious to see the millions of uses.

 

I keep refering to the post #1203 motor photo. That block has had the top machined off of it. I am unsure of the process but, an aluminum plate was bolted to the top of the remaining block, making it closed deck. The deck height is slightly raised. It has had slightly larger sleeves added. I have not personally seen or touched that motor, but I plan to. I have been in contact with the builder. I have seen some of his other work, which is super.

Boss9 Brian,
Any welding on these blocks can cause signifigant warpage. You will likely have to have quite a bit of machining done after that welding. Welding on the filter mount will cause distortion in nearby lifter bores. I hope this is all being done before new sleeve fitment. Cutting out the factory sleeves and installing new ones will also lead to align boring. It may be necessary to remove so much that the cam chain is too short, even with a .010 under chain.

 

My useage is a mini rod pulling tractor. Still under construction

 

Would anyone else be interested in a girdle? I have just started checking out having one built. It appears the expense will be in programing. The more I would have made the cheaper they get.
I am still unsure of the construction. How about some input.

I was thinking 1/2 steel. (Aluminum would expand at the desired rate, but would need to be quite a bit thicker for the strength) These can be made a few ways. The easiest is just mounting to the main cap bolts, but I feel it needs to be pan rail mounted also. There are 2 ways to do that. The pan bolts can run through the girdle thus mounting it, OR a stronger way is to use flush mount tapered bolts to bolt the girdle to the block pan mounts. On the girdle there would be threaded holes added between all the pan bolts to mount a new pan to. The 1st method could use the stock pan but the pickup would have to be lowered 1/2". The 2nd method would require having a pan of your configuration constructed. Make it 1/2" shallower and use the stock pump and pickup or as radical as making a dry sump oiling system.

I am not a machinist. I do a little manual lathe and mill work, but am unfamiliar of any computerized stuff. I think the 1st method (through holes and using longer pan bolts to mount) could be cut on a cnc lazer machine. The 2nd would require a cnc milling machine due to countersunk holes and threaded holes. I expect the lazer would be faster and less expensive. The cnc milling machine cut piece would be more expensive but stronger with the bolting method. A new pan would also add quite a bit to the cost.

 

early in the thread there is a guy with an A441 (race hemi) head with a full deck plate (the liners poke up through a plate that goes all the way out over the lifter area etc. An inch of the outer block has been milled out and replaced with a plate.
About 2/3 of the way through the thread there is a race car - comp eliminator done the same way.

Better than BBC rods are aftermarket 5.4 Ford rods (OE ones are weaker).

Kaase did not significantly redevelop the Boss (twisted Hemi) head. It's a resonably accurate replica of the OE. Slightly different valve train parts, and mounting system, and slightly filled in exhaust ports.

He did relocate the valves and such on the SCJ/P51 wedge head. He also sells versions of the A441 and descendents for racing, which is a pure hemi. Useless at street or semi race build levels on pump gas.

 

Beck : Have you thought about doing the tear drop shape on the crank? The edge hitting the oil first should be round and the back edge will be sharper. It disturbs the oil less. Or possibly even make an aftermarket oil pan with a built in girdle. For your purpose it is understandable to think about one. My engine is just going in my daily driver

 

My deck plate requires no machining on the block besides putting a groove in to weld in and cleaning the welds. And I am by no means building a race car. It is simply a race inspired hot rod. We went with the boss 9 because we have a friend that works for kaase and got us a good price on some blems they were gonna just get rid of.

 

Also, Beck- I would look at the OE mounting of the block.
The actual torque of the engine is not that great in the broader picture of the casting strength. But, I think by mounting it like that- from a low point, with minimal flex, you are asking for a straw breaking the camel's back scenario where the block is internally stressed (and of extremely brittle material- there is a reason no one else does die cast blocks) and snap... JMO...