Mercruiser 470 Motor questions

[jstaguy24]

I just picked up a boat in a trade deal with guy. Its and 81 Silverline with the 470 motor in it. The motor isnt running. I took off the head today. Was already mostly dissassembled from previous owner. Their is rust on the front Cylinder about 3 inches down. Looks as if the motor had sat for some time with moisture in it. Other then when the piston hits that spot it turns over as normal. I was going to hone out the rusted part tomorrow and see how it turns over after that. Looking for opinions on what caused it? bad head, gasket exaust manifold etc and if I hone it and everything seems ok I want to start reassembling, do compression check and such to hopefully get it running. any thing to look for would be appreciated. The oil in the pan looks very clean and new. No water in oil at all.
thanks David

 

[fuzzybob]

Re: Mercruiser 470 Motor questions

Welcome to iboats. You can go to the search feature in this forum and do a search for the 470. There are a ton of posts about it. Spend the evening reading. Good luck on your project.

 

[gettin'even]

Re: Mercruiser 470 Motor questions

I just picked up a boat in a trade deal with guy. Its and 81 Silverline with the 470 motor in it. The motor isnt running. I took off the head today. Was already mostly dissassembled from previous owner. Their is rust on the front Cylinder about 3 inches down. Looks as if the motor had sat for some time with moisture in it. Other then when the piston hits that spot it turns over as normal. I was going to hone out the rusted part tomorrow and see how it turns over after that. Looking for opinions on what caused it? bad head, gasket exaust manifold etc and if I hone it and everything seems ok I want to start reassembling, do compression check and such to hopefully get it running. any thing to look for would be appreciated. The oil in the pan looks very clean and new. No water in oil at all.
thanks David

Any idea on why the previous owner started taking the engine apart? Most people do not dis-assemble a good running engine. Do alot of reading on this engine....and there is alot of reading to do. These engines have thier"flaws".

 

[jstaguy24]

Re: Mercruiser 470 Motor questions

The guy bought the boat under the impression it ran. Guess he never tried it. Found it wouldnt turn over and thats why it is dissassembled to its current point. My only thoughts are it was running, sat for a period of time with moisture getting in that cylinder somehow. and the rust formed above where the piston was resting. Seems ok in rotation till it hits that spot and then binds the piston. going to clean out the cylinder tomorrow and see how it turns over from there.

 

[Rocky_Road]

Re: Mercruiser 470 Motor questions

I have one...and they 'eat' head gaskets like M&M's. Use a Mercruiser gasket, since they seem to hold up much longer. Be sure to torque the head bolts in the proper sequence, and to retorque them after the engine has been run.

Overheating is the main culprit...you have to keep one eye glued on the gauge. When (or if) I get around to fixing my head issue, I will be installing a temperature alarm sending unit wired to a helm buzzer!

If you get the engine up to speed, and need the alternator conversion setup, give me a holler...I have one that I never had to install!

Happy boating!

 

[TowRoper]

Re: Mercruiser 470 Motor questions

look at the bright side it will be easier to see any cracks in the block and head while its off clean it up real good and get close enough with good lighting and check every cm personally i even use a magnifying glass just so its easier to spot things maybe you will be lucky and it was just a head gasket good luck and keep us posted OK!

 

[jstaguy24]

Re: Mercruiser 470 Motor questions

Ok thanks for the info. Their is 2 alternators that came with boat. Havent got that far into it yet

 

[gettin'even]

Re: Mercruiser 470 Motor questions

I have one...and they 'eat' head gaskets like M&M's. Use a Mercruiser gasket, since they seem to hold up much longer. Be sure to torque the head bolts in the proper sequence, and to retorque them after the engine has been run.

Overheating is the main culprit...you have to keep one eye glued on the gauge. When (or if) I get around to fixing my head issue, I will be installing a temperature alarm sending unit wired to a helm buzzer!

If you get the engine up to speed, and need the alternator conversion setup, give me a holler...I have one that I never had to install!

Happy boating!

Sorry to highjack..............but........

Have you had the head and block deck surfaces checked for flatness? Mine had a warped head and a warped block.... Oh yeah, and broken pistons..lol.

 

[jstaguy24]

Re: Mercruiser 470 Motor questions

I just started on the project today. Pulled the head off found the rust. and wont get any further till probably saturday

 

[Rocky_Road]

Re: Mercruiser 470 Motor questions

Sorry to highjack..............but........

Have you had the head and block deck surfaces checked for flatness? Mine had a warped head and a warped block.... Oh yeah, and broken pistons..lol.

Ain't a "highjack"...when you are giving sound input!

Be sure to hang around...he will need all of us 470 owners by the time this is over!

 

[stonyloam]

Re: Mercruiser 470 Motor questions

Was already mostly dissassembled from previous owner. Their is rust on the front Cylinder about 3 inches down. Looks as if the motor had sat for some time with moisture in it.

If that means the exhaust and intake manifolds were off, could be that either a exhaust or intake valve was open and it was just exposure to moisture in the air over time caused the rust. Check the size of the heat exchanger, 3" is bad, 4" is K. Good luck

 

[jstaguy24]

Re: Mercruiser 470 Motor questions

Honed out the cylinder today. Motor turns freely now. Just need to get a gasket set and start re assembling peice by piece and inspecting as I go.
Thanks for all the info everyone

 

[TowRoper]

Re: Mercruiser 470 Motor questions

good job! clean it assemble it and get it on the water!........................done yet?lol

 

[BackWoodsTracker]

Re: Mercruiser 470 Motor questions

OK, this might be considered hijacking. What model Silverline did you get? Any pics?

 

[gettin'even]

Re: Mercruiser 470 Motor questions

Honed out the cylinder today. Motor turns freely now. Just need to get a gasket set and start re assembling peice by piece and inspecting as I go.
Thanks for all the info everyone

You may want to get a machinist's straightedge and feeler gauges, and check the deck of the block and the cylinder head for straightness if you haven't done so already.

 

[natemoore]

Re: Mercruiser 470 Motor questions

You've got a lot of fresh discussions on this engine to read. Gettin' Even and I are currently rebuilding ours. I got my engine back from the machine shop Friday and am assembling it. Your problems are familiar.

Good luck.

 

[jstaguy24]

Re: Mercruiser 470 Motor questions

Does anyone know if you can use a ford 460 head gasket on this engine? I was reading that it is ford 460 head. If not I need to order the gasket set probably from this site as they say they price match. Not sure what the model is dont have the title in front of me but here is a pic of the boat

 

[guyaverage]

Re: Mercruiser 470 Motor questions

A standard 460 head gasket will fit but do NOT use it, it is intended for a iron block/iron head combo. I would vehemently ( ) recommend you only use the OEM Mercruiser gasket for this due to the aluminum block.

 

[jstaguy24]

Re: Mercruiser 470 Motor questions

ok good enough answer for me

 

[natemoore]

Re: Mercruiser 470 Motor questions

ok good enough answer for me

OEM: genuine Quicksilver brand. There are other aftermarket manufacturers of the 470 head gasket, and I often wondered if we were just paying for the name.

I'm told by gettin' even (I think) that the Quicksilver gasket is made by Victor-Reinz, but it is different than the after market Victor-Reinz. He did a side-by-side comparison of the two.

I'm buying Quicksilver brand on the head gasket, aftermarket on everything else.