The elusive 224/3.7 MerCruiser banger

MerCruiser 224 cid/3.7L I4
Bore: 4.36
Stroke: 3.75
Aluminum block
Big block Ford head
SB Chevy transmission compatible bellhousing pattern
170-190hp stock

I have searched high and low and found some information (most of it here on the HAMB), but finding pictures, that don't suck, of these engines is almost as hard as finding the doo-doo bird.

If you have pictures (especially if in a car), or know where to find them, please post them here.

 

I have a Pontiac super duty produced by KRP in Kansas. It has a Brodix 10X aluminum Ford head , shaft mount rockers, dry sump, chevy bolt pattern. It has a single 4 brl intake now and the plan was to install a set of weber side draft or a injection unit and run it in a 27 t. i'll have too get a picture and post it. thw KRP block could be orderd to fit a Ford, Dodge, Pontiac , or chevy v8 head. they ran them in midgets and ARCA truck series.

 

in Model Y frame with Chevy 6 engine mount and V8 frame mount and hose number to get to rear mounted intake inlet

 

One of my buds has 2 of these engines stored under a work bench. They're partially disassembled.

I have to go see him today, I'll try to remember to take a few pics for ya. These are BIG inch 4 cylinders.

 

There is a 27 roadster with 29 fenders here in town with a hot lil Mercruiser in it. Very cool car.

 

Do you have any boat yards/dealers around you? If so, you'll likely find one or two collecting dust/rust in the back lot.

 

PM me Phil1934.
I live in Hampton,and I know we have 'prolly crossed paths,as I know a bunch of folks in Jointsboro.

Lemme' know where you are,if you don't mind me knowing.

 

Here's a pic of the two engines I mentioned yesterday.

Don't pay the blue cylinder head any attention.

 

Thanks for the followup.

 

I wish your pics were bigger and there were more of them.

That blower setup looks bad-ass!!

 

I found this.....

 

It appears that the coolant flows from the water pump to the intake to the head, or vice versa from the head to the intake to the water pump. I also see what appears to be a mechanical fuel pump on the intake side of the block.

 

There are lots of marine salvage yards that sell these engines. i believe they are called 170 mercruisers when you are searching. You still have to drill one hole on the bellhousing. If you push them hard you will need to short fill the block. There's a guy down in florida with one of these in a dragster that's has them pretty scienced out. google red's headers. he does lots of turbo 4 cyl ford stuff.

 

sorry, it's a 470 mercruiser. not a 170. it has 170hp stock.

 

It is a half of a 460 ford engine.

 

4 bbl version is 488, 188 HP. Also 485, 2bbl with hotter cam and 170 MR and 190 MR (redesigned gear housing). Cam lift is .481/.503 for 470, .497/.517 for 488 and .497/.536 for 485 with 1.73 rockers. I put BBC roller rockers on mine as cheaper. As to coolant flow, it is from the radiator to the rear of the intake (488 has oil cooler in intake bottom also), then to the water pump and out the front of the head to the radiator in a street application. You can use a 488 thermostat housing with a Cosworth Vega thermostat housing to make an 1-1/4" inline holder since you eliminate the water cooled exhaust. You will also see the alternator is in the dampener stock.

 

Wow. You're right on top of things aren't you?

 

Phil1034, what is the rpm range with the OEM camshaft?

 

I had Reed regrind mine, but I have some notes the 470 was 269/274 (216/220 @.050") on 114* centers so seems like a mild hot rod cam.

 

Now I know why I moved away from the Northeast. People spend all winter indoors smelling their own farts. I makes them irritable.

 

Found one more....

 

Ford Motorsport had bare blocks in the '87 catalog.

Some info in this thread;
http://www.turboford.net/ubb/ultimatebb.php?ubb=get_topic;f=1;t=000018;p=1

 

But they wanted Mercruiser to add a Ford logo at Mercruiser's expense so the deal fell apart.

 

Don't be a stranger, neighbor. We've got at least one or two at the shop and we've built many of them over the years. Tom Lennon is very familar with their strengths and weaknesses. You wanna build a thumper for a car? Stop by the shop, ask for Tom and tell him Mike said he might know a thing or two about 3.7 Mecruisers. Corner of 20A and CR37 directly across from Raymond's Valley Inn.

-Bigchief.

 

They've had many designations over the years. 170, 270, 470, 3.7, etc. Most dealers hate them as they had too much compression as delivered and the only 'authorized' fix was to pull back the timing which made them horrible to start and run like dogs. The trick is to drop the compression and put the timing back where it needs to be. This actually really wakes them up. We've got a few other tricks up our sleeves on these motors as well.

One drawback is that the water pump is driven off the camshaft. Once the seal surface corrodes/wears away you dump water into the crank case. Another big drawback is the charging system which is integrated into the front cover and is crank driven....and if that were not bad enough it uses a water cooled voltage regulator that dies like a canary on gas if it gets overheated at all. You pull back the timing and tow the kids on the tube while lugging the motor around on cheap gas and the motor tends to get hot. The hot motor kills the complicated and marginal charging system if it doesn't squeak the head gasket in the process.

That being said, they are THUMPERS when set up right. There are speedysleeve repair kits for the cam seal surface and we also have a place that'll sprayweld and regrind the end to size as well. The charging system can be retrofitted with an alternator too.

Cool motors if you've got the coin to do one up.

If you look in the older Ford Motorsports catalogs you'll also notice that Ford offered cams and other parts for these motors for a very short period of time as they were used for some racing class (sprints?) for a while.

-Bigchief.

 

I'd have to go look in the service bulletins, I'm pretty sure Mercury likes to see most of the 3.7's run 4200-4600RPM range at WOT. Keep in mind that a motor at WOT in a boat is basically under a full time dyno pull.....it'll take more RPM than that in the time periods typically seen on the street.....unless your gonna run top end for miles. The cam will run out of steam before you get to 5000RPM.....valve springs and valvetrain limitations.

-Bigchief.

 

Yes I would love to build a 3.7 torque factory for a lightweight T and back it with a full manual, reverse pattern, 700R4. it would be cool. Don't know if I will ever be able to do it though.

 

I used to work on boats, and these motors were nothing but trouble, waterpump, charging system, heads and headgaskets, it never ends.

 

There are after market parts for this engine. you just got to know where to go.I seen one in a chevy monza with a power glide for a tranny .it was
fast mid 11s ,but this was back in the 80s. now with new tech stuff I
am sure there a lot to do for this engine. I will try to get some pics up.
Thanx stew

 

I'm going for it. Bought a merc 470 [parts in a box] a month ago and now am completing the missing parts. Will drop the compression, but don't know how far to go.
[ edited to remove error I made on CR]