Machine shop questions

[gimmieaclue]

I have low compression and am gonna pull the engine in the next day or two. Wet compression test says its the rings so I'm taking it to a machine shop to have them check it out and see if I can get away with new rings and a hone instead of a bore, check the head and other odds and ends.

The motor is a merc 470. I know a lot of people on here are against putting money into them but I've pretty much gone through everything else and just want to make sure I have a reliable motor. Recent new riser, exhaust manifold, bellows, impeller, shift cable, cleaned the cooling system and a few other things. Figure if I get the compression and the cam seal taken care of I'll be in good shape.

I've never done anything like this and am wondering what condition do I take it to them in? Was planning on taking them the block with the head and oil pan still on. And was hoping to get it back in the same condition having all the internals gone through. Is that typical? Do I need to pull the stator? How long does something like this take a shop?

Any other advice is very much welcome
thanks

 

[oldsub86]

Re: Machine shop questions

I would guess they will be happy enough to do it all for you but it will likely be a lot less expensive if you strip it down to a bare block and head. By that I mean, remove the oil pan, oil pump etc but not the crank and pistons etc. If you can re-assemble that sort of thing afterward then it should be less expensive than it will be if they do it all.

Randy

 

[sutor623]

Re: Machine shop questions

Agreed. The machine shop will be glad to do what they do best, machine the block. Im sure some shops wouldnt even want to strip down the motor, unless they are a marine machine shop. If you give them a bare block, the can hone or bore it while you sip a cup of coffee. If you bring in a whole motor, who knows how long it will take. Have you had a look at the cylinder walls through the exhaust plate yet?

 

[gimmieaclue]

Re: Machine shop questions

I have seen the cylinder walls when I did the head gasket (long story there). 123 cylinders looked good 4 had some light scoring and a small nick in the top of the piston.

 

[sutor623]

Re: Machine shop questions

I have seen the cylinder walls when I did the head gasket (long story there). 123 cylinders looked good 4 had some light scoring and a small nick in the top of the piston.

Gotcha. So it sounds like you re-vamped this motor and hoped for the best, but just didnt run as you had hoped? You could honestly probably do a light honing yourself. You can get a honing tool for a drill, set the RPMS accordingly, and count the seconds and strokes out as you do it. I have done it on car motors many times.

 

[sutor623]

Re: Machine shop questions

If not just look into oversized pistons/rings and get a slight bore.

 

[sjohnson44]

Re: Machine shop questions

If I had to do it over again when dealing with a machine shop. I would have took it to them assembled and had them disassemble it and reassemble. Mine was only going to charge $100 extra for that and I didn't do it. I would have saved myself a lot of time and trouble.

Regardless, I still had to wait 3 or 4 weeks for them to rework my engine and heads. (bored .30 over, cleaned, hot tanked, grind the crank, etc.) I got it back with just the pistons, crank, and cam installed.

 

[Bondo]

Re: Machine shop questions

I have low compression and am gonna pull the engine in the next day or two. Wet compression test says its the rings so I'm taking it to a machine shop to have them check it out and see if I can get away with new rings and a hone instead of a bore, check the head and other odds and ends.

The motor is a merc 470. I know a lot of people on here are against putting money into them but I've pretty much gone through everything else and just want to make sure I have a reliable motor. Recent new riser, exhaust manifold, bellows, impeller, shift cable, cleaned the cooling system and a few other things. Figure if I get the compression and the cam seal taken care of I'll be in good shape.

I've never done anything like this and am wondering what condition do I take it to them in? Was planning on taking them the block with the head and oil pan still on. And was hoping to get it back in the same condition having all the internals gone through. Is that typical? Do I need to pull the stator? How long does something like this take a shop?

Any other advice is very much welcome
thanks

Ayuh,.... Before ya do Anything,... Go talk to the Machinist....

Many would rather you bring 'em the whole motor, just as pulled from the barge,...
Others will want it stripped to a certain point,...
None will want it Completely torn down... (unless they're doin' Only the machine work)

'n of course, some don't want the job, at all, for the open deck style motors like the 470....

Most will also reassemble to any point you'd like 'em too...

He can also tell ya whether it needs just honin' or borin', 'n new pistons..

 

[sutor623]

Re: Machine shop questions

If I had to do it over again when dealing with a machine shop. I would have took it to them assembled and had them disassemble it and reassemble. Mine was only going to charge $100 extra for that and I didn't do it. I would have saved myself a lot of time and trouble.

Regardless, I still had to wait 3 or 4 weeks for them to rework my engine and heads. (bored .30 over, cleaned, hot tanked, grind the crank, etc.) I got it back with just the pistons, crank, and cam installed.

Pretty sweet man! Gotta love a good machine shop.

 

[pyrotek]

Re: Machine shop questions

What's a machine shop generally charge for this service? Just curious how it compares to a new engine and why wouldn't people always opt for this option?

 

[dubs283]

Re: Machine shop questions

What's a machine shop generally charge for this service? Just curious how it compares to a new engine and why wouldn't people always opt for this option?

if you are asking this question becuase you have an engine you want rebuilt, you should start your own thread

but, since im already typing - most engine suppliers don't stock remanned 470's, there's not a lot of em out there compared to more common long blocks

as far as the price, it depends on what you want done, seems like the list is endless - that said anywhere from $100 - $10,000+, (not $10k for a 470 though)

 

[Don S]

Re: Machine shop questions

Just curious how it compares to a new engine and why wouldn't people always opt for this option?

Mostly because there are no new 470's. The 3.7 (aka 470) ended manufacturing in 1989.