when to freshen up the 470

[littlelund]

I'm restoring a 26ft islander with a 470 (170 hp) I'm going to run a new SE106 outdrive since the other one locked up tight on the upper. I have the engine on the floor and was a bit worried about it locking up so hard when the outdrive blew. But it still seems to run well. It has probably 1800+ hrs on it mostly trolling. guage reads 2029 but I know the key's been left on a time or two It already has the alternator conversion on it, I need reliablity with this and have been told there are certain things that need to be done every so often on the 470's The cam and lifters being one of them due to cam walk or something. It does smoke a little on cold start up and I'm assuming it's rotted valve seals leaking a little. Can I get some advice from people who know these engines on what I should or shouldn't do. I'm thinking if bore checks out hone and re-ring pistons, new crank and rod bearings, polish crank, new cam kit with valve springs and seals, deck head and maybe a valve/ guide job. New oil pump and coupler while I'm at it. To much, not enough, run it till it blows.. What's the opinions.

Is there any reason hot rod engine builders couldn't handle the task of this engine as long as the specs and tolorances are known. I hear people say car guys don't understand marine applications and I'm not sure why if the specs are known.

 

[Bamaman1]

Re: when to freshen up the 470

If it still runs, I'd leave it alone. When you pull the head, you're likely to be opening a can of worms.

If and when it completely breaks, go find yourself a good used engine or one rebuilt by a professional.

Mine dropped a thrust bearing down into the oil pan, and I never got around to reassembling it after getting machine work done. I still have all the parts (including a new gasket kit) and a fresh head sitting in storage.

 

[littlelund]

Re: when to freshen up the 470

Yeah maybe I'll just invest in a good reliable kicker and run it till she blows. I plan on the family going out a lot so with small kids it needs to be able to get back in off the great lakes. Are there areas of concern with the 470's like cam seals, gaskets, or anything in particular that I should think about changing out while it's sitting there.

 

[HT32BSX115]

Re: when to freshen up the 470

Yeah maybe I'll just invest in a good reliable kicker and run it till she blows. I plan on the family going out a lot so with small kids it needs to be able to get back in off the great lakes. Are there areas of concern with the 470's like cam seals, gaskets, or anything in particular that I should think about changing out while it's sitting there.

There are MANY areas of concern with a "470"

Mercruiser 470 Coolant Leak

A search will reveal most of all you need to know....

 

[matt167]

Re: when to freshen up the 470

If you are restoring, and replacing the drive anyway. Fit it with a Mercruiser 4.3L Alpha One. That's what most of the newer Islanders ran from the factory. It will pay for itself in piece of mind and parts if something ever happened. 470 has a diminishing amount of parts with quite a bit being NLA as it is, so they are $$$.
Hotrodders love the 224/3.7L CI 4cyl ( aKA 470 ), so offloading it would be easy. Very light engine ( even lighter with aluminum head ), can crank near 200hp without forced induction, that's the basic reason on why they are well regarded in the hotrodding world...

As far as automotive people not knowing the marine engines, that is 100% true and to understand it, they have to change thinking because it is all different. I know because I come from the automotive way of thinking. Bearing clearences and that kind of thing are same as automotive, but camshaft recomendations, oil specifications, gasket specifications, everything right down to operating temps are all Marine spec.

 

[littlelund]

Re: when to freshen up the 470

I've thought of the 4.3 since it uses the same outdrive ratio. But some say it's more trouble then it's worth. The Islander has two big beams in the engine pit that would easily accomodate pretty much anything but does anyone know how to line it all up and actually put the mounts where they need to be? Anybody know of a "how to" on this conversion? I'm assuming a pull out 4.3 with engine mounts, exhaust, and wiring in theory would bolt/plug right in if one could align it all up?

 

[Bamaman1]

Re: when to freshen up the 470

I have read that the 470 transom plate will only fit a 470, and that other engines will not quite fit it. A 4.3 donor boat is preferable to get all the parts you'd need for the conversion.

(I have a boat with a 470 blown engine.)

 

[fmalott]

Re: when to freshen up the 470

best thing to do is check the compression reason is the 470 motor the #4 cylinder is the first one to lose compression because the head is cast and the bottom end is aluminum so the head warps so if the compression is good run her to the ground. the cam seals are the next thing to worry about if you don't see no antifreeze leaking out the weep hole then your good to go when you start seeing these two things getting worse start finding a new 4.3 get it ready when the 470 blows. there is still tons of parts out there i had no problem finding them when i rebuilt my 470 and it wasn't cheap. with all the parts you want to change it will cost anywhere from $3000-$4000 to rebuild

 

[HT32BSX115]

Re: when to freshen up the 470

with all the parts you want to change it will cost anywhere from $3000-$4000 to rebuild

In 2005, Out of a local, damaged '98 Bilgeliner, I bought a complete 1997 Mercruiser 7.4L engine, transom mount, Bravo III drive, fan-belt to Props with 122 hrs since new, for $5000.

THEN, over the next few years, I sold all the OMC 460 Cobra junk I removed (piece by piece) for a total of about $3500..........

In your case, I would run the current engine and drive and between now and next spring find a damaged boat with a late model(low time) 4.3L engine and drive..........buy the boat......... rebuild/replace the 4.3l engine and swap it all out in late Spring or late Summer and sell the 470 engine/drive/parts in the following winter.

You would probably come out better than you think..........

 

[stonyloam]

Re: when to freshen up the 470

I have read that the 470 transom plate will only fit a 470, and that other engines will not quite fit it. A 4.3 donor boat is preferable to get all the parts you'd need for the conversion.

That is not correct. For years 83-90 there is only an alpha1 transom plate (44117A8), so for his vintage boat (85 I believe he said) they should be all the same.