Preventative Head Gasket Replacement and more - 470/170

[Rake722]

[FONT=&quot]I found me a 470 with only 66 hours on it, its a 1978 build and I plan to fit the boat with it and take the boat to a remote location in Greece so wanted to do the nasty bits before taking it over. Its been sat in a shed for the past 25 years so I plan to do the following ?[/FONT]
[FONT=&quot]Later alloy exhaust manifold
New starter
Alternator conversion
Pertronix ignition
Rebuild carb
4 Inch HE
Remove watercooled regulator and stator
Headgasket replacement
Cam seal replacement and camshaft inspection.[/FONT]
[FONT=&quot]I wanted to ask if there is anything else I should consider ?
Also is there any nasty surprises when doing the headgasket ? Any common problems ?[/FONT]
[FONT=&quot]Many thanks.[/FONT]
[FONT=&quot]Rake[/FONT]

 

[harleyman1975]

My concern with an engine that has been sitting this long is that everything is dried out like valve seals, oil seals, gaskets, water pump seals, ect... the other thing I would check for is corrosion from non use (cyl bore, camshaft, ect...). I am humbly suggesting that you tear it down and inspect and re-gasket and re seal the entire motor.

 

[Scott Danforth]

regarding the head gasket, only use OEM Mercruiser

you realize your list of upgrades will cost you more than simply swapping in a 4.3 and throwing that turd of a motor away

 

[Rake722]

Scott thank you, I knew someone would say something like that and it really plays on my insecurity about this engine BUT - the upgrades have already been done to my existing engine so the cost is only the cost of the gaskets and the cost of the replacement engine which has very low hours.

I would go for the 4.3 but it would cost me some ?4000 more than my current path.

Many thanks

ron.

 

[stonyloam]

Get a manual and follow the instructions EXACTLY if you replace the head gasket. Once it is replaced make sure you run it up to operating temperature then retorque the head bolts. That is a must! If you pull the head, you might consider taking it to a machine shop and having hardened exhaust seats installed.

 

[Rake722]

Thanks Terry - Great advice.

IMO the head is coming off, it will give me a change to check the bores and rings etc. Is there any point in doing the speedy sleeve fix or even chroming / hardening the cam while in there ?

 

[Scott Danforth]

you have to do the speedy sleeve fix.

 

[stonyloam]

If the surface of the cam is smooth and not grooved you do not need to use a Speedi Sleeve. I would not worry about chroming or hardening the cam surface, especially with just a few hours. The front seal is the most critical, and remember BOTH seals face (garter Spring side) away from the block toward the coolant. The new seals are a lot better than they were 30 years ago. If the sealing surface of the cam is grooved, pitted or rough, then yeah go with the sleeves. In either case you should get 10 years or so out of the new seals. Just make sure the weep hole is clear and check it when it is running and up to temperature as part of your regular routine.