Possible Mercruiser 470 purchase. Concerns?

[NWVintage]

Alright, so I am looking at a new boat. It is a 1978 19' Glasply cuddy with a mercruiser 470 and an alpha one outdrive. I have done quite a bit of research and I am aware that the earlier 470's - of which this is one - had a 3" heat exchanger that did not always cool the adequately and that they came with a stator-style charging system that often causes problems. I have also talked with several who say to replace the charging system when it begins to give you issues and idle-down slowly after hard runs for adequate cooling. I have had the boat gone through by a mechanic and everything seems good. Good compression; all of the fluids were full and in good shape when he changed them; no water or grit in the lower unit fluid; shifts smoothly; charging system at about 13.5-14 volts.

Are there any other specific things that I ought to take a closer look at?

Please, don't just say "don't buy it," every motor has its issues and I am aware that there are some out there with a hatred for this motor; but that's true of all motors and I am looking for real, constructive, useful thoughts. Issues are unavoidable, I just want to know where the highest potential lies so that I can examine and monitor those.

Thanks for your input.

 

[stonyloam]

Re: Possible Mercruiser 470 purchase. Concerns?

You seem to be going in with your eyes wide open. Any 34 year old boat is going to have problems, just educate yourself so that you can do routine maintenance yourself. Like any 470 keep an eye on the engine coolant pump. If it starts leaking out of the weep hole (lower starboard side) you will have to replace the seals. Other than that, have fun. If you have problems there are lots of folks here to help. Welcome to the 470 club, maybe.

 

[cheaperts]

Re: Possible Mercruiser 470 purchase. Concerns?

I too just bought a 31 year old 470, and I too was/am worried by all that I've read. The upshot of it all for me was that IF it is in really good condition, maintained well, the motor is actually quite a powerful yet reasonably efficent set up, my 18' bowrider jumps to plane and screams down the lake with it. I don't think its a good option if there is any significant problems, and if it is still all original (as mine is) then you just have to accept and plan/budget for charging system conversion and probably swapping to a 4" exchanger. I love the 470, but hey I also root for the Cubs..............

 

[TilliamWe]

Re: Possible Mercruiser 470 purchase. Concerns?

...I love the 470, but hey I also root for the Cubs..............

Wow! I have never seen two sadder statements in one place!

 

[Bondo]

Re: Possible Mercruiser 470 purchase. Concerns?

Please, don't just say "don't buy it," every motor has its issues

Ayuh,... The Difference is,... You can Buy the parts to fix most other boat motors....

The 470 has been Abandoned by Mercruiser....

 

[billbayliner]

Re: Possible Mercruiser 470 purchase. Concerns?

Yes every engine has it's issues. Unfortunately this one has more than many others.

Strong points:
Lots of power.
Lots of torque.
Easy to source cylinder head replacement.

Weak points:
OEM charging system.... fix = Delco 10si kit = $$$$$
Camshaft drives engine cooling circ pump... shared seal area... problematic.
Drive ratio is unique to this engine as I understand it.
No longer in production and has not been for years.

 

[HT32BSX115]

Re: Possible Mercruiser 470 purchase. Concerns?

Are there any other specific things that I ought to take a closer look at?

Absolutely!!

Go to your local Mercruiser dealer.

Ask them what they will be charging for all the "normal" repair parts and service. Ask them "how much" for a head gasket, ignition parts, raw water pump, alternator parts, riser gaskets, riser, intake/exhaust manifolds, camshaft, camshaft seals and other engine gaskets, water (circulating) pump and any other parts they might recommend.

THEN ASK them if you should buy it!

Please, don't just say "don't buy it," every motor has its issues and I am aware that there are some out there with a hatred for this motor; but that's true of all motors and I am looking for real, constructive, useful thoughts. Issues are unavoidable, I just want to know where the highest potential lies so that I can examine and monitor those.

The highest potential was when they were new. All the "plus's" mentioned above.

The negatives are also mentioned above.

Because there's MANY other boat choices out there that are available with engine/drive systems that are still supportable.............. The "negatives" FAR OUTWEIGH the plus's.


There's a LOT of people here that have them and have broken the code on keeping them running but if you ask them if they would buy another one, most will say they wish they'd gotten something else. (they usually don't like to admit that, though) Same with OMC Cobras....I broke the code on how to keep my previous King Kobra running but I wouldn't do it again!!!!

So........ DON'T BUY IT. JMHO.......


God luck! (you'll need it if you get it!)


Rick

 

[vincechig1975]

Re: Possible Mercruiser 470 purchase. Concerns?

I hope you guys don'tmind if I chime in here....I am rebuilding my 470 as a backup motor, swapping out for a 4.3 chevy, still like my 470 to be honest but prefer the 4.3, less issues with it but yet as they say every one has it's problems just a matter of how much $$$$ you want to spend. Still learning as I go Good Luck

 

[NWVintage]

Re: Possible Mercruiser 470 purchase. Concerns?

Thanks for all of the input. Not seeing any new info though. Anyone?

HT32BSX115 - First, as I stated above, it was just at a certified Mercruiser mechanic and he said that everything looks good. Second, you shouldn't own a 34 year old boat if you have to take it to a mechanic. Third, the parts: full gasket set for the head (all of them, not just the head gasket) $80, raw water $30, riser gaskets $10, risers $90 - they all seem downright reasonable. And, because it's not a V-configuration, there's only one of each part - no double-ups on gaskets, cams, etc. Sure manifolds, camshafts, and the like are expensive but, if you need those, you've done something wrong and ought to be punished (also you can get good shape, functional used on ebay for about 1/10 the price of new).

Like I said. ISSUES TO LOOK FOR please. Not, innuendo that if you let your risers get super gunked-up and leave them long enough to allow your exhaust manifold to rust out and then take it to the dealer and he makes you buy a brand new manifold and you pay the mechanic for the install and ... it costs $4000... I have a friend who had to rebuild his dad's 4.3 last summer because of precisely this problem. He cautioned me about manifolds but then we got to talking and realized that it was neglect, not manifolds that caused the issue.

billbayliner - thanks. I've looked into that alternator conversion. I will probably fabricate a bracket and I will probably cheat and use an automotive alternator (Delco 130 amp 1-wire). This boat will be trailer-stored in my driveway, I don't see corrosion being much of an issue. I don't make a habit of using automotive parts on boats but over $1000 for an alternator is simply ridiculous and I doubt it will cause any issues. And the seal issue was a good thing to be brought up. I have been advised to watch that and I will. I'll watch closely for leaks this year and replace all of the top-end gaskets next winter.

Also, just a general note. Once the charging system and heat exchanger are changed, I think that I would probably prefer this engine over a 4.3 - lower fuel consumption, lighter, about the same hp, inline for fewer parts. Granted this motor has been "abandoned" but only after many years and they abandoned it for a Chevy block that Chevy manufactures, rather than manufacturing their own block and mating it with a Ford head. I'd say the decision probably had much more to do with streamlining their operation than it did abandoning a flawed design.

A complete rebuild of this engine will cost less than $1500 and I can probably keep it under $1000. But that won't come for a few years.

 

[NWVintage]

Re: Possible Mercruiser 470 purchase. Concerns?

Oop...

Just found a company near me that sells complete 95 amp alternator conversions for a 470 for $395 USD...

brackets, alternator, hardware, belt, wiring harness B-)

 

[billbayliner]

Re: Possible Mercruiser 470 purchase. Concerns?

You did ask for input here.
Just a general statement.... some people come to a forum already knowing what they want to hear, and don't want to hear. Best to not get caught up in that.
Most of what the guys here are saying is to inform you about what you're getting yourself into with this engine. These do have good points but also some not so good points.
It sounds like you have the skills to work on and overhaul one if needed. That's good.

The mechanic that you talked to may like the 470 because he's spent years working on them. Maybe he loves the work generated from them. Don't know.

As for the auto Delco 10si, it won't meet USCG regs, and it could be dangerous because it's not ignition source protected. You can screen the auto version using the marine screening parts.
The front and rear screening system turns this

into this.

By the time you find the screening parts, you might as well buy the Marine version.

 

[NWVintage]

Re: Possible Mercruiser 470 purchase. Concerns?

billbayliner-

I apologize if my prior post seemed excessively negative. As you said, some points were not so helpful and I found them frustrating. Its as if they were responding only to the heading and didn't read any of the actual post.

The mechanic didn't say, "you must buy this boat," or anything. He just said that everything works fine and that all motors have problems, just know what to look for.

Thank you for your input, especially regarding the alternator. This will be the first I/O that I've actually owned (not the first I've worked on, not my first boat) and some of these intricacies are precisely the types of things that I at least need to be informed of so that I can weigh my options and make intelligent choices. I was also under-informed on the pricing of these items - I could swear they were $800-$900 when I was looking the other day... Marine grade, it is!

The water-pump/camshaft seal was also a very good piece of info. Exactly the type of stuff I was looking for.

Thanks

 

[fmalott]

Re: Possible Mercruiser 470 purchase. Concerns?

totally ignore the 470 haters i rebuilt my 1983 470 this winter and you hit the nail right on the head "IF it is in really good condition, maintained well", it will last you for many years. when i did my research the common problems to look out for is the voltage regulator i highly recommend converting right now before it does create a problem, another is the 3" heat exchanger everybody recommends the 4" which is true but i heard if you keep the 3" clean it works under normal useage but 4" is better, another is the cam seals they wear a groove on the cam which makes the seals leak then you need to put a speedy sleeve on to correct it, another thing is the head gasket because the head is cast and the motor is aluminun the #4 clylinder seems to be the first place the head gasket fails so every now and then do compression checks to keep your eye on the head gasket and get the head machined the 460 ford head has a habit of warping. just to add to it i changed my points to electronic ignition when i did the alternater conversion. there is one down fall there is still many parts out there for the 470 i had no problem finding them but it was very expensive to rebuild i have no regrets but expensive
P.S. i went through the same thing when i asked for advise i got more 470 hater comments then advise so just ignore them the 470 is a great motor WHEN IT'S MAINTAINED RIGHT it will last for years

 

[ezmobee]

Re: Possible Mercruiser 470 purchase. Concerns?

I love it when people start threads and then debate all the responses.

You guys are right. The 470 is an awesome motor. The only thing better than a 470 is two 470s!!

 

[NWVintage]

Re: Possible Mercruiser 470 purchase. Concerns?

another is the cam seals they wear a groove on the cam which makes the seals leak then you need to put a speedy sleeve on to correct it, another thing is the head gasket because the head is cast and the motor is aluminun the #4 clylinder seems to be the first place the head gasket fails so every now and then do compression checks to keep your eye on the head gasket and get the head machined the 460 ford head has a habit of warping.

Thanks. That's actually very relevant. Compression is a little low on 4 - not alarmingly low, but a couple psi lower than the rest and maybe that's the answer. Is the cam seal issue a more-or-less inevitable thing? Thanks

there is one down fall there is still many parts out there for the 470 i had no problem finding them but it was very expensive to rebuild i have no regrets but expensive

Where there any specific parts that were excessively expensive?

P.S. i went through the same thing when i asked for advise i got more 470 hater comments then advise so just ignore them the 470 is a great motor WHEN IT'S MAINTAINED RIGHT it will last for years

I know, right? The only guy that said, "holy crap! don't buy it!" is the guy who provided no actual information...

Thank you again to everyone with meaningful input.

 

[fmalott]

Re: Possible Mercruiser 470 purchase. Concerns?

Thanks. That's actually very relevant. Compression is a little low on 4 - not alarmingly low, but a couple psi lower than the rest and maybe that's the answer. Is the cam seal issue a more-or-less inevitable thing? Thanks



Where there any specific parts that were excessively expensive?



I know, right? The only guy that said, "holy crap! don't buy it!" is the guy who provided no actual information...

Thank you again to everyone with meaningful input.

no matter what you do the cam seals will wear a groove, when the motor is in the boat you can change the seals then also pain in the *^# but it can be done. as for expensive parts i needed a new exhaust manifold that is very expensive, the alternator conversion was 400 dollars. i did a complete rebuild new rod bearings and crank shaft bearings new fuel pump. it all depends on what you want to do just look up the parts and you will see the price on the parts GOOD LUCK!
PS one last thing you will be alright with a couple of pounds lower BUT that's an indication the head gasket is starting to fail if you pull the motor get the head machined and new head gasket you will be just fine

 

[NWVintage]

Re: Possible Mercruiser 470 purchase. Concerns?

no matter what you do the cam seals will wear a groove, when the motor is in the boat you can change the seals then also pain in the *^# but it can be done. as for expensive parts i needed a new exhaust manifold that is very expensive, the alternator conversion was 400 dollars. i did a complete rebuild new rod bearings and crank shaft bearings new fuel pump. it all depends on what you want to do just look up the parts and you will see the price on the parts GOOD LUCK!
PS one last thing you will be alright with a couple of pounds lower BUT that's an indication the head gasket is starting to fail if you pull the motor get the head machined and new head gasket you will be just fine

What was the deal with the exhaust manifold? Was there a specific reason that it needed to be replaced? Most people I've talked to that have had to replace an exhaust manifold had to do so because they neglected their risers which rusted out and thus allowed raw salt water into the manifold. The advice I've received from several more experienced boaters in my social circle is to service risers very regularly and replace at the first sign of wear.

Also, for anyone reading, I've seen several used 470 exhaust manifolds on ebay for about $100-$150. Thorough photos, high-rated sellers.

Any guideline on what people think about the head gasket wear - do we think it can make a 100 hour season (Season will be a bit limited this year - new baby...)? I can't remember the exact numbers but it was something like 130, 130, 129, 127. I'd probably get a full-head gasket kit and clean/inspect everything (including head planing) after fall fishing.

As for the cam seals - I'd need cam seals and a "speedy sleeve"? Can you explain a speedy sleeve? I've never had any issues with cam seals wearing grooves on other motors that I've been involved with.

 

[fmalott]

Re: Possible Mercruiser 470 purchase. Concerns?

the reason i replaced my exhaust manifold it was cracked how the crack got there i don't know there could be many reason my riser was in great shape. it's a matter of timing if you can find a used one for a good deal get it. as for the compression you should be alright but don't run it to hard. when i did a compression test on my motor it was 145 150 145 130 so with a 15-20lb difference i knew my head gasket was in bad shape that why i rebuilt the motor and machined the head. you might have a head gasket problem but with those readings there pretty close to being the same it could be just wear on the rings. i did the rings just in case i did not have to bore the cylinders out they where close enough to standard bore so i just honed out and replaced rings and when i took out the pistons i notice my rod bearings had pretty good wear on them so i replaced rod bearings and crank bearings.
as for the cam seals they will wear a groove on the cam i can't explain why but they do when i rebuilt my motor i had the cam out i was measuring the cam lobes to make sure there was no excesive wear and i noticed my cam had grooves where the cam seals are, mine where not deep enough to put a speedy sleeve on. i never had to deal with grooves either so i did some research and learned what speedy sleeves do. just look it up and it will explain what a speedy sleeve does here is a picture anyways of a speedy sleeve