Mercruiser 470 rebuild, questions, suggestions, valued input requested

[sstroudwku]

I've lurked these forums for some time. I've seen/read all the pros and cons to the 470. Yet I love this little engine anyway. I love it more because it's a troublesome guy much like I was in my younger years and I appreciate the spirit it has. I've only had it about a year, it's mounted in a sporty little 1980 Formula Thunderbird 16'9" closed bow. The previous owner loved the boat as well. He took great care in maintaining the engine. It's still the original gloss black on the and looks fantastic. Unfortunately this year when I pulled him out of storage and fired it up, I have the infamous cam seal leak. DUN DUN DUNNNNNNNNNN. Now I am quite mechanically incline. By trade I'm a Nissan/ASE master technician. So you can see I'm no afraid of a good challenge. That being said I decided the ole fella deserves a good overhaul. Plans are to remove the engine and do a pan up refresh. Bearings, Rings, seals, plan on weight matching the rods, having the crank balanced. It's already been converted to an alternator, and the 4" heat exchanger. Still has the points ignition though which will have to go. My questions to you fellow 470 owners, and guys who have especially serviced, rebuilt, upgraded theirs is this. I need a good source for rebuild parts, bearings, seals, redi-sleeves, ect. Suggestions on electronic ignition upgrades I've heard pros and cons about the pertronix kit, are their other options available? I've seen several guys convert to roller rocker, if you have where did you source the rockers and push rods? I know each rod will need to be measured individually and if I recall reading correctly a spacer needs to be installed between the head and rocker cover. I also plan to convert it to an electronic fuel pump and possible mock a TBI setup or convert to the 490 4bbl. I have a PDF copy of the original Merc manual and plan to print and bind it so I have a good source for rebuild instructions.

I know many of these questions have been asked, I have searched the forums a good bit and to be quite honest I find that every thread is met with the same statements "RUN AWAY, TOO EXPENSIVE, NOT RELIABLE". I do understand the issues that go along with this engine, but I enjoy it, I'm not afraid to put money into it. If I wanted a new boat I'd go out and buy one, but I prefer to breathing new life into older things that have memories built around them. When I'm cruising across the lake I drift off and imagine the first time this boat was in the water, what it's first owner was thinking listening to the engine purring behind him.

Thanks for the time fellas. If you have any car questions I'll be glad to help.

 

[bently]

I used to own a 3.7 and have the two cam seals and timing cover seal, new still in the package. I can send you the part numbers, when I get home from work and if you are interested (Edit: see rule #8)

 

[stonyloam]

Love your enthusiasm, not sure, on a cost benefit basis you are going to gain much from all of that work. First off you are basically working on a truck engine, and will never be running over about 42-4400 RPM. IMHO you should rebuild for strength and reliability. OK where to spend the money: You have a 80 "old" style engine, I would upgrade to the newer 86-89 style aluminum exhaust manifold, reservoir and exhaust elbow, probably need the whole exhaust system. When you pull the head, have hardened exhaust valve seats put in. If you want a 4 bbl, the best bet is probably a used OEM manifold and carb ( not that easy to find). The head is a Ford 460, so if you want roller rockers that is probably where to start. For sure use a OEM Mercruiser head gasket (not aftermarket or Ford). Have the distributor rebuilt and the advance springs checked. I have a Petronix Ignitor II, with a Petronix Flamethrower II, which I like. New OEM plug wires are a perfect fit. If you go with an electric fuel pump you will need a fuel pump relay and a oil pressure switch, so that if you lose oil pressure the pump turns off. plenty of info on the web for wiring a MARINE electric fuel pump. This is a good reference for parts breakdowns https://www.mercruiserparts.com. That is my 2 cents. Good luck, and welcome to the 470 Club.

 

[sstroudwku]

Bently - That'd be fantastic always done for a good deal.

Stonyloam - you sir are the kind of gentlemen I like to bounce ideas off of. Understandably the engine is a big brute, and should stay the 4400rpm range I agree. Looking to change the prop to a 4 blade 19p to help get out of the hole a little better. And probably losing the dolphin tale for a set of smart tabs. My young ones aren't excited to hit 20mph on the tube just to plane out the boat. Good idea on the oil pressure switch and relay, I would not have thought about that and it makes sense. I'm a wiring nut and looking at the loom under the sundeck of my boat just drives me crazy. I'll probably redo the entire electrical system putting it into harness sections for easy removal. I notice you emphasized a marine fuel pump, is there a difference between it and lets say an Accel performer or walbro inline?
As for wires I made a set of MSD wires from a set of Street Fire performer 8mm wires I had. I'll take your advice on reliability vs performance as well when it boils down to it, it's still a 470 and as it sits now I GPS'd 51mph last year on a smooth lake. Thanks for the input and the website, my search begins for the exhaust system.

Do you have a photo of this aluminum one installed, images I'm finding on the web look identical to the one installed on my boat, curious if the PO had this done already.

 

[stonyloam]

Here is what the "new" styl looks like https://www.mercruiserparts.com/Sho...=EXHAUST+MANIFOLD+AND+EXHAUST+ELBOW(ALUMINUM) And the " old" https://www.mercruiserparts.com/Sho...&bnbr=6&bdesc=Exhaust+Manifold+and+Elbow(MCM) the new styl has either a cast iron or aluminum manifold. Either is ok, the Al is just a little nicer LOL.

 

[stonyloam]

Back th the marine stuff: Everything electrical or fuel related must be marine rated, to prevent fuel explosions due to fuel vapors accumulating in the enclosed bilge area. That means your starter, alternator ( check with the PO) and ignition system. You do not want any stray sparks. On your fuel system you do not want anything dumping fuel into the bilge. Your carb is a special marine carb, the tank has a anti siphon ( spring loaded ball valve) in the line to prevent fuel from coming out unless it is actually being sucked out and your mechanical fuel pump has a clear tube running up to the carb to dump fuel into the carb in the case of a pump diaphragm rupture. Your marine electric fuel pump is designed to meet the electrical specs. With the electric pump, when you hit the start switch the relay closes and your pump runs, when the engine starts you return to run and the start relay opens, but as soon as the oil pressure builds the oil pressure switch closes and energizes the relay and the fuel pump runs. If if you should have a fuel line rupture the engine stops and lack of oil pressure shuts off the pump, so you do not have to contend with a bilge ful of gas. I know one of the 470 guys here went with an Airtex pump.

 

[sstroudwku]

Makes good sense, which is why I joined in the first place, wouldn't have thought about that. Thanks for clarification on the later manifolds. I double checked, my is the older style front mount reservoir. I've found several, the whole kit ranges from 1300-1900 depending where you buy it. Being the bargain hunter I am I feel like a good used set that I media blast and paint would work just as well. I didn't see a classifieds section here in the forums. Do you have to reach a certain post count? or a paid subscription?

 

[stonyloam]

No classifieds here, but I think this is legal: You would need the manifold and the exhaust pipes http://www.mercruiserparts.com/Show_...=EXHAUST+ELBOW check e-bay http://www.ebay.com/itm/USED-FREWSHW...67e3c1&vxp=mtr (it looks like it is Al, but better check with seller) and http://www.ebay.com/itm/MerCruiser-4...bd7f7d&vxp=mtr plus you need the bellows and shutters (see parts diagram).

 

[sstroudwku]

No classifieds here, but I think this is legal: You would need the manifold and the exhaust pipes http://www.mercruiserparts.com/Show_...=EXHAUST+ELBOW check e-bay http://www.ebay.com/itm/USED-FREWSHW...67e3c1&vxp=mtr (it looks like it is Al, but better check with seller) and http://www.ebay.com/itm/MerCruiser-4...bd7f7d&vxp=mtr plus you need the bellows and shutters (see parts diagram).

You're simply a plethora of useful information. If you were here I'd owe you a beer. So far with everything I have carted all merc/quicksilver parts (rod bearings, crank bearings, piston rings, complete gasket set, all conversion parts for AL exhaust) I'm only around $750 in parts. Still need to get the redi sleeve, but I believe I need to wait until after the engine is out and I can measure the correct? I chose not to do cam bearings yet, wait and see the condition of the cam when I get the engine apart. Also need the pertronix kit, you wouldn't happen to know that part number off hand? Thanks again. Once it's out and stripped I'll get pictures of the rebuild. Boat is bright yellow, so the block and head will be yellow with a white pan, intake, exhaust. Or possibly vice/versa.

 

[stonyloam]

Of course LOL: Igniitor II 91146A, coil Flamethrower II 45011 oil filled, 45111 epoxy, if you want chrome 45001 http://pertronix.com/catalogs/ignition/default.aspx

 

[Bondo]

You're simply a plethora of useful information.

Ayuh,...... Welcome Aboard,...... I consider Terry to be our resident 470 Expert,.....

 

[mr 88]

Having had one rebuilt last year with and finding the cylinders egged out I have a feeling your going to run into the same issue .Might have to return rings when buying new pistons to fit bored out cylinder.Changed it to a 4 barrel as well ,don't forget to snag a valve cover from a 4 barrel donor as well. The throttle cable is routed diffferent due to linkage setup for the 4 barrel and attaches to the top of the valve cover.

 

[mr 88]

And with the throttle cable re-routed your probably going to come up short.So plan on buying a longer cable. Make sure you get the carb spacer that sits on the manifold as well. Need it so throttle cable can hook up properly

 

[stonyloam]

Here is some interesting reading on what the hot Rodders do with 470's: http://www.jalopyjournal.com/forum/t...banger.256713/ They discuss roller rockers and aluminum
heads. This too: https://m.youtube.com/watch?v=ldeUvKat94Y
Aha! I knew this was here somewhere! http://forums.iboats.com/forum/engin...uild-with-pics

 

[sstroudwku]

Wow, Sorry I got slammed at work this week. I'd get home and just want to relax. This is a bunch of useful info. Bearings, rings, gasket kit on the way. I'm torn on the manifold stuff. I'd like to get it, my iron stuff is in great shape though, just torn. Sell me on the benefits maybe?

 

[mr 88]

Depends on what you want to do,it's not a race boat and to gain 2mph it's going to cost you.I came across a pkg deal when swapping to a 4 barrel and its pushing a 22' Center Console which has a heavy load it in most of the time.I had props kicking around so I didn't have to pony up for new one which you might have too and I re-routed my throttle cable, being a CC it was easy, saving more money.I would go stock with the rebuild ,throw in a petronix ign[ just about any 12volt coil will work ,they market there own coil but its bs,just a profitable add on.] then with the money you saved buy some beer/ gas/fishing equip/water toys for the summer and enjoy it. I can't sell you on the benefits because you will never recoup what you put in to it . The maybe 2mph vs the cost vs the purpose of boat to me isn't worth it. Buying the correct prop and running as light as you can will have you going almost as fast as the 4 barrel with all the upgrades you want to do.Then again if thats what you want to do don't let me rain on your parade its your project! Hopefully someone chimes in on the benefits to confuse you more,haha.

 

[stonyloam]

Yeah, with a 16' boat that already does 51 mph you should have all you need with the 2 bbl. I do think switching to the " new" exhaust system is a worthwhile investment. Mostly because it was the latest improvements to the design, less prone to cracking ( so I have heard) and a better exhaust shutter setup. I'll agree with 88, on the prop, when you get it running, see how it goes with the current prop. If it responds well and WOT is in the correct range you might be OK. If you think you might want to change down the line, the prop forum here is a great place to look for help.

 

[sstroudwku]

You guys are right, I have no need to go any faster. The prop change is for a better hole shot and to plane a bit quicker along with the nautical smart tabs.

On the exhaust system I'm finding the manifold is aluminum but the reservoirs seem to be Cast. Is this normal?

-------- went ahead and got it ------ manifold, elbow, and remaining exhaust for $350. I had a feeler out there and a guy wanted $500 just for the manifold.

So bearings, rings, manifold, elbow, exhaust, pertronix kit w/ coil all ordered. Need the bellows for the exhaust still mine are new, curious if they'll work. Oh and a set of blemished smart tabs sx from iboats.

Just time to pull the engine and do the rebuild. Full repaint. Gotta pull it and get it blasted and prepped for paint.

 

[stonyloam]

Yeah, Al manifold, cast reservoir. Make sure you get the correct gasket (for the Al manifold/reservoir). When you get it there will be a hose fitting sticking out of the side. That is where the raw water from the exchanger dumps into the exhaust. Make sure that is unobstructed, sometimes there can be some rust buildup. I don't think the bellows will fit, and you will need a new exhaust shutter and grommets too. Might want to check that the bolts and studs on your block fit the new manifold. You got a real deal on that setup, and I think you will be happy with it. Took a look at the photos, looks like you have one of the bellows, and your shutter looks like it is intact, just check it to make sure the rubber is in good shape. You might contact the seller and see if the other bellow is laying around there.

 

[sstroudwku]

Thanks again for all the help. My wife is a camera nut so I'm sure I'll end up with a huge gallery of photos during the build. I plan during fastener removal to replace everything with either ARP fasteners or Hex head replacements. I rarely reuse the same fasteners during a rebuild. The fact it's GM/Ford I'm sure ARP will have everything I need, even if it's another couple hundred in fasteners.