My Merc 470 rebuild

[alexr254]

I just wated to start a thread with my rebuild process. Possibly get some hints or pointers along the way.And hopefully help a few folks out who are doing the same type of project. This is my first ever rebuild, and i am doing it with my dad, which has some knowledge with motors from like 30 years ago.

First off, i have heard lots of criticism about me rebuilding the engine.. its a dinosour, not worth it, etc etc.. I dont care about any of that, i like this engine and am sticking to my rebuild.

I inherited 2 merc 470 3.7ltr engines, both were in unknown condition, one was "newer" then the other. One was from 1987 (came with no head) and the other was from 1991.

So i planned on rebuilduilding the 91. looked clean from outside, but when i checked internals it was messed up bad. The 87 is actually in better shape on certain parts, but was obviously left outside for a while so the piston rings got locked bad, and some other parts got rusted.

So first thing I did was got the head that came with the 91 cut , and resealed.

The 87 since it was frozen i gutted to get the block regrinded, The crankshaft also has some rust but the bearings are all in really good shape. I will get that grinded down anyway due to the rust on the shaft.

I will end up using the 91 as the complete rebuild. When opened it up, the oil was 50/50 water, and considering how the crankshaft and oil pump filter looked, it was run like this . The crankshaft and rod bearings are messed up with burn lines all in them. I will have the crankshaft and block grinded and replace all bearings and pistons.


I would appreciate any hints or pointers about the complete rebuild process of this engine type. Maybe something i may have missed or even upgraded parts i can possibly use to maximize engine life.

I did purchase the alternator upgrade kit already for this engine (from breezeworks, great guys there!), and i do plan on getting the electronic ignition conversion.

 

[stonyloam]

Re: My Merc 470 rebuild

Alex good for you. There are a couple of really good 470 rebuild threads here. Go up to the "Community" tab, hit "member list", then "member search" and look up these two guys: natemoore, and nola mike go to their profiles and look for started threads, both have done a really nice job of writing about their rebuilds. Will answer a lot of your questions and show you how to make some of the special tools you will need. Have fun.

 

[Fordiesel69]

Re: My Merc 470 rebuild

After your rebuild, make certain to find the 4" heat exchanger. Yours may have the 3" which is not adequate under most conditions.

Also do not use a universal all makes & models coolant. Stick with old timer Zerex Conventional Green. GM Dexcool, Supertech, Valuecraft all makes, etc will speed up the dreaded cam seal leak.

If you can afford a new cam, this is the only way our local marina's will do it. They no longer do a speedie sleeve.

 

[alexr254]

Re: My Merc 470 rebuild

Stonyloam:
Thanks, very usefeul threads!

Fordiesel69:
Yup i do have the 4" heat exchanger.

I am not sure what you mean about the cam. so far i see no issues with my camshaft, except the seals of course, but the shaft itself I left in the block for now while the machine shop regrinds the piston cylinders in the engine block and the crankshaft (which is removed).

Unfortunately my local marina is not an option for anything, and i do not plan on ever going there for any service question or request. The way they see it, if i cant afford a new engine at a minimum of $7k, i am not worth their time.

on another note, i just want to say that by no means am i a professional engine mechanic. I am doing this as a passtime with my father whose health is deteriorating. He is retired and needs something to keep his mind off of stressful things. And of course this engine will be put into good use on a nice 27ft cruiser (twin engines). I am by trade a IT system engineer, so i like doing research and learning new things. I have always had a desire to gut an engine and see how they work, and finally i have the opportunity. So again thanks for your understanding, sharing of priceless knowledge and experience.

 

[stonyloam]

Re: My Merc 470 rebuild

I am not sure what you mean about the cam.

The engine waterpump on a 470 is driven directly by the camshaft. There are two seals in the timing cover that ride on the end of the cam that prevent the coolant from leaking. These seals eventually ware out and start to leak so they need to be replaced. Read this: http://www.sterndrives.com/470information/470coolantleakrepair.html Your engine is apart so it should be no problem to repair. One note, both seals face the same direction, away from the block (the garter spring in the seals should be facing away from the block). The crank oil seal in the timing cover faces (garter spring) toward the block. Here is a parts diagram: http://www.mercruiserparts.com/Show...88/35.png&inbr=908&bnbr=170&bdesc=FRONT+COVER cam seals are #2, oil seal is #3

 

[alexr254]

Re: My Merc 470 rebuild

Ok got it.

I assumed Fordiesel69 was stating something about me replacing the entire camshaft for a new one, and not just working on the seals.

I by all means will replace ALL seals and ALL gaskets and will pay most attention to the notoriously truoblesome issues (camshaft seals being one), which i am finding on these forums as i move along.

 

[stonyloam]

Re: My Merc 470 rebuild

The seals can ware a groove in the cam where they contact. If the groove is bad enough the new seals may leak. That is why they recommend the spedi sleeves to repair the cam surface, Fordiesel is saying his marina replaces the cam rather than repairing. For what it is worth when I did mine, I did not know about the sleeves and just replaced the seals, 7+ years ago and still working fine.

 

[alexr254]

Re: My Merc 470 rebuild

ok cool. I will see how bad the camshaft is once i get the block back from the machine shop. I did google the speedi sleeve, and its definately a cheap fix compared to replacing the entire camshaft.

Also i do have 2 camshafts to choose from, so i will compare and pick the best shape one.

So right now i am in standby mode waiting for the machine shop to finish my 2 blocks and 2 crankshafts. When i get those back and start putting it together i will post any issues.. And if all goes well i will post that also

Thanks for the help

 

[stonyloam]

Re: My Merc 470 rebuild

Do you have the mercruiser manual. You need #8. Here is a link to download: http://www.4shared.com/document/zTbCbkDD/Service_Manual_08.html

 

[salty3rd]

Re: My Merc 470 rebuild

One thing you must be careful of since you are mixing and matching engine parts; is make sure you use the correct pushrods that were in that engine..I believe there were four different lengths of pushrods that were used in those engines. Good Luck; Bill

 

[telstar1]

Re: My Merc 470 rebuild

The speedi sleeve comes into play if there is a groove in the camshaft. They work very well in my exp. Measure the lobe lift on your camshaft. Its easy.Sometimes some of them get worn down quite a bit for reasons I have no idea about.

 

[Bt Doctur]

Re: My Merc 470 rebuild

for the oil pump install, install the pump but dont tighten it down untill you install the dist.the dist shaft will locate the pump correctly, then tighten the oil pump mounting bolts.the allen shaft will break if not exactly lined up with the female part of the oil pump.

 

[alexr254]

Re: My Merc 470 rebuild

quick update, the block and crankshaft are both still in the machine shop waiting to get finished.

got my 4 barrel rochester carb rebuilt, and got new head bolts.

still waiting... eventually i will get to the outdrive... ouch!
but its well worth it thinking about how awesome it will be once were out on the water just cruisin'

For those who wonder how much something like this cost on average, so far i have used roughly $1300 into this rebuild.
this includes:
Block Boring
CrankShaft grinding
New pistons
New bearings
Head cut
New head bolts
Alt conv kit
Carb rebuild
Overhaul gasket set

does not include any tools and stuff like that.

I have studied all the awesome tips you have given, once we start assembling they will all come into play. cant wait.

 

[Eric 3.7LX Alpha 1]

Re: My Merc 470 rebuild

Another thing, if you are re-using the cam, which ever one you decide, you have to keep track of the lifters for it, and be sure they go back in the same spot on the camshaft the came out of. They have a wear pattern on them and if they go to a different lobe it can wipe out the cam.

You can use a old camshaft and buy all new lifters and that would not be a problem if you are not sure on them.

 

[alexr254]

Re: My Merc 470 rebuild

i have a question:

the machinist asked me if the engine is reverse rotation or forward rotation.... I have no idea how to answer that question.

This engine is from the starboard side. Does this make any difference for rotation?

sorry i am at a loss on this one.

 

[stonyloam]

Re: My Merc 470 rebuild

I am pretty sure all of the 470s rotate in the same direction. If it ran backwards the cam driven waterpump would run backwards wouldn't it? That (and I am sticking my neck out here) is counterclockwise, looking at the back of the flywheel. Someone please correct me if I am wrong. You could take a look at the starters, to make sure.

 

[alexr254]

Re: My Merc 470 rebuild

What is the difference between the stock starter and the ARCO starter? I see the ARCO is much more expensive.

I have a good ARCO starter on the starborad engine. The port engine which we are also rebuilding has a bad starter and we need to replace it. But i am not sure if i should get the cheaper stock one or the expensive ARCO.

 

[stonyloam]

Re: My Merc 470 rebuild

Take a look at this one, http://www.motorcityreman.com/memaoe5050502.html is what I have and it works fine (thanks for the link Eric)

 

[artificialreef]

Re: My Merc 470 rebuild

Hello Alex, I am excited for you on your builds and am eager to follow your progress. Coincidentally I to am an IT professional that bought a 27ft. boat with nonrunning twin 470's. Mine is a 1983 26.5 Tiara continental that is trashed and has been siting for at a min 2 years maybe more. I am hoping i dont have to rebuild just yet as i did a compression test on both and they turn and hold a decent comp. 145lb +- i think. Anyhow before i get flagged for just chatting. I wanted to mention that i am 49 and remember how points work. (i bet your dad does too) and am going to try to old school mine and get them running with the points. Are you aware of the pertronix conversion for this? You definately need to get rid of the stator for an alt conversion and the dizzy conversion is something to consider. I have read they run better with it. At least easier to maintain. What kind of vessel did you get?

 

[artificialreef]

Re: My Merc 470 rebuild

Breezeworks.net is also a good message board source. If money is no object read up on putting ford aluminum heads on. It has bennys like the block is aluminum and will expand and contract at the relatively same rate. These motors will blow a gasket in a heartbeat because of the cast iron heads and aluminum blocks. I read that you have to pay attention to the push rod lengths and have to drill something out (cooling inlet?)but if i had unlimited time, help, and dollars would maybe toss on a pair of those.