Mercruiser 470 rebuild

[ImperialV184]

I am in the process of rebuilding a 470, designated by the mercruiser 165. It is an inline 4 from about 1987. Thus far i have remove everything but the cam, crank shaft, fuel filter and oil pump. I was hoping to hone and reassemble but the no 4 bore has some pitting that may be an issue, has anyone had any luck boring out a single cylinder? are parts available for this type of operation?

 

[telstar1]

Re: mericruiser 470 rebuild

Re: mericruiser 470 rebuild

I am in the process of rebuilding a 470, designated by the mercruiser 165. It is an inline 4 from about 1987. Thus far i have remove everything but the cam, crank shaft, fuel filter and oil pump. I was hoping to hone and reassemble but the no 4 bore has some pitting that may be an issue, has anyone had any luck boring out a single cylinder? are parts available for this type of operation?

I have not done this(one cyl only) but was told by machine shop it could be done as long as it was not a large amount (maybe only 5 thou I cannot remember exactly).I got all 4 done as reboring is actually quite cheap. The pistons were expensive tho. cannot remember the price exactly, perhaps $60 each. Consult an engine rebuild shop they should have all the data and prices. Yes the parts are available.

 

[ImperialV184]

Re: mericruiser 470 rebuild

Re: mericruiser 470 rebuild

Iboaters, started this post a while back but started using some more specific posts to get me through this rebuild, wanted to provide a better update for my progress thus far.

I inherited a 1987 imperial form my father in law and when i got it home it was in pretty rough shape, i knew the boat was rotten but i was hoping for a sold engine............but that was not the case i started into a full rebuild of the boat an engine. here is a shot if the boat shortly after i got it home and tore out the carpet.

I quickly realized the engine had to come out to fix the boat, i had some help getting the engine out form a local boat shop, i had them put it on a dolly and i came back with a trailer to pick up the engine. Man that thing weighs a lot more than i thought.

I knew very little about the 470 So i just went with what i could see and i saw that the head was badly corroded as well as the starter motor. so i figured i will start with getting out the starter.

check out this rust old starter, had to pound it out with a mallet from the other side. had to remove the flywheel cover and even then it took a tremendous amount of force to get it out.

here is the view behind the flywheel cover.

After reading a lot of post and talking to some folks at work, i realized the next step was to take off the head and see what i had going on inside the cylinders. I knew the engine overheated last time is was used so i figured i might have a riser or gasket issue.

intake and exhaust manifolds came off easy, but this was an indication that i was dealing with a pretty good amount of work, this is the intake side of the head.

exhaust side showed some green crystals which indicated coolant was getting into the head possibly through the riser.

 

[ImperialV184]

Re: mericruiser 470 rebuild

Re: mericruiser 470 rebuild

Next i removed the head and the number 4 was looking pretty bad............did some thinking for a while, thought a bout swapping out the engine, read up on all the design and maintenance issues and made the decision to go for the full rebuild.

headed to harbor freight to get her a proper engine stand and the project began

 

[gear79]

Re: Mercruiser 470 rebuild

I'm curious on anything else you find here, I have the same engine so I'm subscribing. Good luck.

 

[fmalott]

Re: Mercruiser 470 rebuild

i did a complete rebuild on my 83 470 and learnt alot from this forum. take the head to a machine shop they can rebuild the head no problem. the # 4 cylinder is always the problem on these 470's because the head is cast and the motor is aluminum they don't like each other so the head would warp and the first place it would leak is the #4 cylinder. as for the cylinder it's self i'm not sure if you can do just one by the pictures it looks like more then 5 thou you need to bore out best thing to do is go to a machine shop and get there opinion. make sure you take a good look at your riser and manifold for leaks and cracks and rust clogs on the riser get your self a manual they are the bible
and you will be told by alot of 470 owners to convert to a alternator i see you still have the voltage regulator, the best thing you can do is convert. and while your at it convert to electronic ignition. also take a very close look at your cam shaft the impeller is driven by the cam there is two seals that the cam shaft goes threw they will wear a groove on the cam shaft and it will leak past the seals that's another common problem with the 470's. best thing to do is add up all your money and see if it's cheaper to rebuild or find a donor motor
it cost me $3000 to rebuild so GOODLUCK! keep posting you will get alot of help from this forum
P.S. drop the oil pan to see if water got to the bottom end

 

[ImperialV184]

Re: Mercruiser 470 rebuild

Dropped the pan and did see a slight bit of water in the pan, but not nearly as much as I thought I would see based on what I saw in the cylinder

i took off the front cover to inspect the cam seal issue, what I found is the cam seal did start to wear through seal one but did not make it through seal two, plan to replace seals and speddi sleeve the cam but this does not appear o be an area of coolant leakage

 

[fmalott]

Re: Mercruiser 470 rebuild

agreed the cam seals are not your leaking problem but i just mentioned since you already pulled the motor it's a good time to check. as for you leaking problem like i said before get the head rebuilt some one who specializes in doing heads will have no problem rebuilding it and check your manifold and riser for cracks and make sure you clean the riser of rust clogs, one more thing to look at is the surface of the riser and the manifold were they meet together the surfaces have to be cleaned very well meaning the surface has to be nice like the head would be, the riser has a bad habit of corroding on the surface and inturn would leak