Evinrude rebuild

[grotmeister]

Hi all! just about to rebuild my 60hp twin 1980's powerhead. Had it rebored and head skimmed after a meltdown a while ago. I've got a clymer manual but not sure its much good, any advice? I've never worked on marine engines before! but a fair amount of automotive experience over the years. many many questions to come!!! Cheers in advance

 

[Dhadley]

Re: Evinrude rebuild

Welcome!!<br /><br />Be very very careful with a head thats been cut for that motor. If its been cut much at all you might want to think about richening up the carbs. .010 is a lot and about as much as you want to go. If you decked the block too then you probably should rejet. Make darn sure you use cool Champion plugs.

 

[grotmeister]

Re: Evinrude rebuild

Hi Dhad, thanks for that. The head looked like the surface of the moon so I had it welded and skimmed, I don't think too much came off it. By the way do I need to do anything to the new bores before installing the pistons?

 

[jy118lfd]

Re: Evinrude rebuild

Listen to dhadley (I don't think) sounds like a set up for disaster. There are plenty of good used parts around. If the head has any pits in the chamber, a lot on this site will say it is trash. Carbon will get in there and turn red hot and set up detonation couple that with a cut head and you have a recipe for piston lunch. You will have Too much work involved to just think.

 

[Dhadley]

Re: Evinrude rebuild

Not quite sure by what you mean about the "new bores". If the block has been bored it should have been finished honed and deburred. <br /><br />It almost sounds like an automotive machine shop did the boring. If so be careful. In any case find out what they used for a finished bore size. Not just ".020 or .030 over". You need to know exactly what the finished bore size is (actual measurement to .0000 at room temperature).<br /><br />Did you find out what caused the first "meltdown"? If not you may be in for a repete performance.

 

[R.Johnson]

Re: Evinrude rebuild

Where did they do the welding on that head? If on the gas, and oil soaked interior, replace it.

 

[grotmeister]

Re: Evinrude rebuild

yeah I was thinking about finding a another head anyway. Dhadley it was an automotive shop that did the work but I chose that one as he has rebuilt rolls royce engines for years. The bores have criss-cross patterns on them and he has put a slight chamfer on the transfer ports. I'll phone him tommorrow to see if he kept a record of the exact finished bore diameter. Ssome aditional info: Pistons are Wiseco part no.s 3111P3 +030. Engine is Evinrude BE60TLCO Ser no:G1048497. I don't know what caused the meltdown, bought engine for next to nothing already blown, thought it a good time to get to know marine engines! I've read loads fromthis forum and getting the picture LOL. Thanks guys for taking the trouble to reply.<br />Chris

 

[R.Johnson]

Re: Evinrude rebuild

Roll's are four cycle automotive engine's, they just cost more.

 

[grotmeister]

Re: Evinrude rebuild

i'd like to clean up all the engine casings etc with shot blasting equipment prior to reassembly, does anyone know any reasons why I shouldn't do this??

 

[Dhadley]

Re: Evinrude rebuild

You dont want to shot peen the parts except maybe the rods (but I cant imagine why youd want to). You can bead blast the block, heads and covers with very light air pressure and a fine media. But you have to be sure to get rid of all the residue. And be careful around the mating areas. It needs to be done before the machine work is done. Youll want to put bolts in every hole to keep the media out.<br /><br />Basically if you havent done it before, youre better off to not do it now.<br /><br />I'd almost bet that the block is bored too tight. Its very common with automotive shops. Just like automotive shops are used to decking the block and cutting the head. A real "careful now" / no-no in Marineland.

 

[grotmeister]

Re: Evinrude rebuild

cheers Dhadley, still gotta check dimensions of new bores, was thinking of using aluminium oxide media and masking off the insides first, but maybe i'll just clean it all up by hand. Have just got OMC manual off ebay-yippee!

 

[Dhadley]

Re: Evinrude rebuild

Before you do anything get the exact finished bore size. To 0.0000". And don't let them read it from a book. We know what the book says, we wanna know what the cylinders are.

 

[grotmeister]

Re: Evinrude rebuild

have spoken to engineers, they bored out the block to 3.2275" does that sound right? <br />Thanks <br />Chris

 

[grotmeister]

Re: Evinrude rebuild

sorry mistyped that: 3.2475"

 

[Dhadley]

Re: Evinrude rebuild

The standard bore for that motor is 3.1875".<br /> <br />So .030 os would be 3.2175" <br /><br />3.2475" is .060" over. I have no idea where you will find pistons for that. The 3111P3's will definately not work.

 

[grotmeister]

Re: Evinrude rebuild

thanks for replying Dhad!I think i misinterpreted what engineer told me lol. He said the bore was 3.2175 +030 so I sort of assumed I had to add the +030. I've got the piston in the bore right in front of me and there aint no 60 thou gap there! looks to me with the piston resting on the side of the bore about 005-008 gap at the topside but not got a feeler gage to hand to measure that. Gotta be sure this is right before starting to assemble the thing.

 

[grotmeister]

Re: Evinrude rebuild

just pressed one ring half inch into the bore with the piston crown think there's about a 010 gap between the ends of the ring. will buy some feeler gages 2morrow and get a more accurate reading

 

[grotmeister]

Re: Evinrude rebuild

Question for Dhadley. Ok; with the block on its side and piston resting in the bore, i can just slide the tip of a 025" feeler into the gap between the piston and bore, the gap between the ends of the ring is 020", what d'ya reckon?<br />thanks in advance <br />chris

 

[Dhadley]

Re: Evinrude rebuild

The ring gap is correct. That tells us the bore is approximately correct. If it is indeed bored to 3.2175, thats the absolute minimum. It will work but youll want to break it in very very carefully. The thermostats and pressure relief valves must be in place and working correctly. <br /><br />If it were mine I'd let it idle for 4 hours before attempting to put it under a load of aany kind. You can put the 4 hours on it 1/2 hour at a time or all at one time. On the hose or in the water. It doesnt matter. We'd really rather see the bore at another .0005 (3.218) but youre OK. This is very typical of an automotive shop.

 

[rodbolt]

Re: Evinrude rebuild

listen to what Dhadley is telling you. I have had some of the same issues with wiesco pistons. the OMC bore size is for cast pistons not forged.<br /> you also want to make sure the engine is fully warmed up before placing it under much load. piston to wall clearence is measured at the piston skirt area not the ringland area. the skirt is larger than the lands. you will find on the 2cyl looper skirt sealing is critical to idle quality.<br /> you will also need to rebuild the carbs and water pump as well as the fuel pump. the old pistons will usually tell you why it died.