Big inch four: Mercruiser 470/485

Well, lately I have stumbled across threads where the Mercruiser 470/480 engines have been mentioned, and only this evening finally found mention of someone who has actually run one (Randy Dupree) ( and @ Bonneville, no less
So, after a quick PM asking for more info, I suggested that my questions be answered here, in a post so that others may also benefit from any info.
Here's what I know so far: Built by Mercury Marine from approx 1978? to about 1984?.....aluminum block, using Ford "385" series (aka: 429/460) cyllinder head. 470 version was 2bbl, w/170HP rating, while the 485 was 4bbl w/180HP rating.
Here are some things I'd like to know:
1)How practical is adaptation to a STREET driven car?
2)What bolt pattern is the back of the block?
3) How much parts interchangeability is there with a 460 Ford (ie: connecting rods, main/rod brgs, etc?
4) If #3 is none, are the mercury parts still available and affordable?
I'm sure there is more to ask, but that's a good start

PS: If there are any errors in the above info, let me know and I will edit!

Thanks in Advance to Randy for taking time to respond.
James

 

This will be a great thread if we get some replys. I alwas wanted to put an aluminum cj head and go all aluminum on one.

 

Well what I know/found out !! The back of the engine is CHEVY ! bellhousing and crank flange is standard Chevy, so easy hookup to common parts. Now this is what I've been told crank is special to this engine , pistons,rods, head 460 Ford. Have heard problems with having iron head on a aluminum block ,heads cracking. Seems you couls fix that with a aftermarket aluminum head. I found out about this engine after my T was setup for the ChevyII style 4 banger other wise I proubly would have went with one.

 

The best head to use would be to run an Edelbrock 429/460 head. I think you will have to redo the waterpump setup as it's setup to run-outside water-lake/river. There use to be an aftermarket 4 barrel intake for this engine--almost bought one a few years back. Would make a great Track T engine.--Good luck
Dutch

 

hmm, now im going to keep my eyes peeled for marine engines

 

here are some older threads I just found with a bit more info....I will add any others as they turn up

http://www.jalopyjournal.com/forum/showthread.php?t=256713&highlight=mercruiser

http://www.jalopyjournal.com/forum/showthread.php?t=139812&highlight=mercruiser

http://www.jalopyjournal.com/forum/showthread.php?t=132183&highlight=mercruiser



James

 

you know, Ive been looking at some of those high horsepower big outboards and wondering if there was a way, but im not sure if Ive got it all figured out yet.

 

Crank flange is neutral balance 289 or 250 six

 

well...not exactly Chevrolet. It is very close to the Chevy pattern I've heard compared to a barn shape. A dowel pin or two doesn't line up according to my research on this same topic. Also the Chevy starter will not work. You need either the original starter (may or may not work) or I have read that an International Harvester V8 (70's era) starter will work.

One other thing on these engineis the alternator. The OEM unit is built into one of the pulleys (crank if I recall) and is prone to failure and is realitvly low output. There are, however, automotive style alternator kits. I bit pricey but a permanent solution to the issue.

There is yet another thing to be cautious about. Something to do with a seal on the cam failing and causing problems. But I am not not up to speed on that issue.

 

To clarify that's 289 Ford or 250 I6 Ford.

The 300 Ford I6 is neutral balance and may also be a source for a crank pulley. This is a total hypothesis on my part though.

 

This thread is going to be good. I am working on two of them right now. Both with boos 429 heads.

I have been looking for info for these motors for a while and there isn't much out there. From what I have seen the bell housing will bolt up to a chevy but there was one whole that needed to be moved I think I will check again when I get to the shop. The rods I pulled out of the two I have both were cast with the 429 cobra jet part numbers. The cranks in these things are really heavy. I just got mine back from the machinest where we were able to take about ten pound off of it. Also we turned down the rod journals to accept chrysler rods. The hardest thing for me to find right now is some one to build me a cam shaft.

Keep the info coming.

 

In stock form, junk junk junk junk junk! I am a master certified Mecrcruiser tech for 12 years now. Prone to blown head gaskets, cracked heads, poor charging, bad ignition etc. Is and was a problem child from day one. Please pm if you need any specific info, be glad to help.

Jon

 

Just send the cam for a regrind and add adjustable studs and rockers. Starter is 392 IH, but not obtainable, so best to stick with Mercruiser. The owner of http://www.innovationeng.com/ had a Jon Kaase built Boss headed BBC rodded stroker Mercruiser in a dragster. There is an extended bellhousing so he can do a flywheel if you need. If auto you can just shim.

 

Well I guess I stand corrected!! Got my info from Phoenix area midget guru Dave Ellis who first told me about this engine. Interesting engine none the less.

Bastard try Delta Cams ,have had good luck with them.Running a 350 HP Chevy grind in my 153 now and got to order the same for the 181 I'm now building.

 

bastard: PICS!!......we need PICS!!! (I've got my own kleenex)

James

 

Man, it amazes me how many alias' there are for this engine!

Mercruiser 470 / 485 / 488 / 170 / 180 / 190 / 165
...and I know from the bit of digging I have done that they started around 1978, but this link tells me they went later than I had previously believed (1989?)

http://www.sterndrive.info/sterndriveparts/manifold_model_165_170_180_190.html

....and here's another with even more alias'
http://www.jasperengines.com/pdf/37LMerCruiserIgnitionTB.pdf

...and this one has parts diagrams (broken out by years/serial number ranges)
http://www.perfprotech.com/store/catalog/Mercruiser-Parts-Finder,3172.aspx


James

 

Here are some things I'd like to know:
1)How practical is adaptation to a STREET driven car? I finished a rebuilt of my friend/neighbors 32 roadster wiyj on of these engines. You would be suprised at how much power that thing makes and how easy it is to drive on the street in a light car.
2)What bolt pattern is the back of the block? he was using a turbo 400 behind the engine. If I recall correctly the 2 top bolt holes had to be modified the dowel locations and the 4 nolts around the dowels were run as is.
3) How much parts interchangeability is there with a 460 Ford (ie: connecting rods, main/rod brgs, etc? About the only thing that is Ford is the head. If I recall corectly the crankshft is from a britsh leyland tractor and everything else is unique to the mercruiser.
4) If #3 is none, are the mercury parts still available and affordable?
I'm sure there is more to ask, but that's a good start Parts are still available from mercruiser and are priced right up there with aviation parts. There are still a few marine mechanics that will work on one of these engine, however around here most of the dearships dont want to know about them. Just so you know even though it was marine engine it ran a closed cooling system so if you find one that was run in salt water is should not be a problem.

PS: If there are any errors in the above info, let me know and I will edit!

Thanks in Advance to Randy for taking time to respond.
James
PM me if you need more info, my friend still has this car and lives 2 blocks away from me, I can get more info from him. Another friend who is a marine mechanic used to work on these engines, I dont know if he still does, but I am sure he has not forgotten anything, I could ask him questions as well.

 

There isn't much to take pics of right now. Just got the rocker arms in And the pro charger for one of the motors. Next we have to get the valves and springs here then port the head. These heads are costing me a fortune so I have to buy the parts slowly. I will have about 4 grand in each head when they are done. Hope to have the motors done by end of the winter. Should have the chassis for the anglia that on motor is going in done by then also.

 

" the 485 was 4bbl w/180HP rating. " ??

I don't know jack about these motors or pretty much anything, but do I have this correct?: 485 ci with a 4 bbl carb and only 180hp made in the 70's and 80's and this is an interesting motor for some reason?

I must be missing something about this. Maybe 485 cc's?

 

Bastard: What got me going on the 4 cyll research in the first place is my vision of a super-light, 4 cyll Thames delivery.....so I would be interested in seeing what you are putting together......have you posted anything in other threads ( this thread may not be the place, but I would definately like to see what you are working on

James

 

STUDE: Yup, youre missing something....485 is one of the many model designations used for the 224 CID 4 cyl, it is not a cubic inch displacement.....

James

 

Nothing yet Have had a 48 anglia body sitting in pops garage for the last 25 years. We decide a few months ago to do some thing with it. So right now we are just gathering all the parts to put it together. First on the list is the motor. Once we start on it I will start a thread on the build. Probably be a few more months.

 

boats that have these engines in them are hard to sell and don't sell for much, they had the alternator built into the front of the crankshaft balancer and are expensive to repair along with oil leaks and other problems

 

Come on now.....I'm a Merc tech too and these motors have thier quirks but are easy to fix. Problem #1 is that they had too much compresion from the factory. The 'fix' from Mercury was to pull back the timing. Between the bad gas, pulled back timing, over proping and relatively heavy boats these were put into and you've got a perfect recipe for detonation and overheating. Which takes out the voltage regulator (water cooled) and the head gasket. The REAL fix is to install a set of dished 460 pistons which lowers the compression to run on todays swill. NOW you can put the timing where it belongs and the motor has more power and runs cool which keeps everything happy. Problem #2, weak charging system, is somewhat eleviated by fixing problem #1 but they still suck. For the automotive application one would definitely want to axe the OEM charging system and build brackets for a conventional alternator. Problem #3 is the water pump is cam driven and when the seal surface on the camshaft fails it allows water and oil to mix. Not good. Again, new cams and speedi-sleeves are readily available to solve the problem.

We do several of these motors every year. Once they are "fixed" they just keep running and making stupid torque.

-Bigchief.

 

Main and rod bearings are readily available from Clevite and Sealed Power and are MUCH cheaper than the Mercury Marine parts. Whats nice is that the center main/thrust bearing is INCLUDED with the bearing set whereas Mercury dings you an extra 100 beans for it if you buy the bearings from them. They are specific to the 3.7 (aka470/485 et.all). The rods, pistons and head are based on Ford parts. The front of the head has a large hole machined in it for a water circulation. The rods are Ford rods but the 429/460 bearings will not work with the Merc crank....tangs/radii issues if I remember correctly. Use dished 460 pistons if your going with a low buck iron head......you can keep the flat tops if your running an alumium head.

Ford Motorsports briefly offered these blocks, cams, etc back in the 80's for a sprint car program.....there apparently was a pissing contest over labeling/branding on the block between Ford and Mercury and the program was stopped.....or something to that effect. Some blocks have lifter bushings installed at the factory, this is normal due to manufacturing issues during the run. The bushed blocks are fine. Some blocks also have cam bearings whereas others run the cam directly in the block....again, Mercury correcting tolerance/alignment issues at the factory, the blocks perform well regardless.

ALSO something that nobody mentions is the fact that there is a special Mercury tool required for correct positioning of components during shortblock assembly. Without the tool you may end up with no oil pressure. I'll dig up more information on that subject soon.

PM me if you'd like more information and/or parts for these motors.

-Bigchief.

 

BIGCHIEF: Don't hold out on us man!!
The whole premise of this thread is to gather as much intel on these engines in one place as possible. The less unknown's, the more likely people will forge ahead and build one.........

Thanks!
James

 

So Big Chief, How many HOSSES can this engine make on a less expensive build with the dished pistons/iron head ETC....Can it be an economical (MPG) engine and can one be built with a reasonable outlay of Dollars ?....How would it compare $$$ to a stock Chevy SBC rebuild ???

 

Man would really like to know more on this subject. So please keep us posted.

 

One horse per cube is with grasp if you have a good intake and header design on an otherwise close to stock 3.7. These are not known as mileage kings......maybe mid teens or better on a mild build. Remember its basically 1/2 of a 460. Define reasonable outlay of dollars.....if your comparing it to a $895 GM350 long block special out of Pep-Boys then there's no comparison. If your comparing it a high quality rebuild on a 350 (typically $3000-$4000 depending on parts choice) then its comparable in near-stock form.

 

phil is right,the chevy flywheel will not fit.