Omc 115 Turbojet stripped down and starting the rebuild

[Abomb27]

Re: Omc 115 Turbojet stripped down and starting the rebuild

I going to pickup my block in a little bit. I am putting together a parts list. I want to know if wrist pin bearing, rod bearings, and crankshaft bearings. Do these automatically get replaced when you rebuild, or do you reuse them. I see no signs of wear no marks, or lines or anything. But I want to do the right thing here. So get new or use if they are good?

 

[Abomb27]

Re: Omc 115 Turbojet stripped down and starting the rebuild

Picked up the block. Guy says its has to be bored. Said significant compression loss on the cylinder that had the one ring, right by the exhaust ports. Now I am trying to find a place that can bore it.

 

[boobie]

Re: Omc 115 Turbojet stripped down and starting the rebuild

When I do a motor and it just has a blown piston and all the bearings looked good I'd reuse them. JMHO. May want to replace the bearings on the cylinder that blew though.

 

[Abomb27]

Re: Omc 115 Turbojet stripped down and starting the rebuild

Thanks boobie. Thats kind of what I was thinking. Getting parts can get expensive quick.

 

[boobie]

Re: Omc 115 Turbojet stripped down and starting the rebuild

Yeah, I know. Keep us posted.

 

[Abomb27]

Re: Omc 115 Turbojet stripped down and starting the rebuild

I found a guy that does all the machine work for the marinas. I gave him the block asked him to bore it. He told me the right way to do the job, is to have the new pistons. He said there are slight variances from different manufacturers, and it is best to bore it to the piston size. Also that with outboards you want to bore to the smallest oversize you can. It sounded good to me. He is going to recheck the bore and see if he can go .020 in. OS. Then he is going to get the pistons and bore it. He is charging the same price for the pistons as I found them for. So I let him get them, easier for me. Should be ready next week.

 

[racerone]

Re: Omc 115 Turbojet stripped down and starting the rebuild

Nowadays the pistons are much more accurately machined than they were in the old days.---Boring to the oversize is common without having the piston in hand.-----But if he insists on it , then it sounds like your block is in good hands.

 

[boobie]

Re: Omc 115 Turbojet stripped down and starting the rebuild

What pistons did you end up with ??

 

[Abomb27]

Re: Omc 115 Turbojet stripped down and starting the rebuild

I talked to the guy and he thought that wiseco was a better piston. So he is ordering wiseco pistons .020 over sized.

 

[boobie]

Re: Omc 115 Turbojet stripped down and starting the rebuild

Be sure to follow the break in procedures for those pistons.

 

[boobie]

Re: Omc 115 Turbojet stripped down and starting the rebuild

An after thought. We used those pistons years ago in snowmobiles and they were damn good.

 

[Abomb27]

Re: Omc 115 Turbojet stripped down and starting the rebuild

Glad to hear that. For some reason I have been second guessing my choice. Hopefully they will work well.

 

[boobie]

Re: Omc 115 Turbojet stripped down and starting the rebuild

Read post # 30 again.:joyous:

 

[Abomb27]

Re: Omc 115 Turbojet stripped down and starting the rebuild

Thats probably really critical. I have my maunal for break in, but I will have to check to see if wiseco recommends anything additional. Thanks boobie.

 

[racerone]

Re: Omc 115 Turbojet stripped down and starting the rebuild

Break in instruction come with the new pistons.--Get a copy from the shop.

 

[Abomb27]

Re: Omc 115 Turbojet stripped down and starting the rebuild

I will make sure I get them. Thanks

 

[racerone]

Re: Omc 115 Turbojet stripped down and starting the rebuild

Also make sure the turbo jet engine is not idling too slow.--------Proper cooling is critical and I believe it must idle above 1200 RPM

 

[Abomb27]

Re: Omc 115 Turbojet stripped down and starting the rebuild

Cooling was an issue when I first got the boat. I had a combination of problems. Bad head gaskets, got the heads machined replaced gasket and cylinder head cover gasket. The thermostats were corroded shut. After I got those issues fixed. I then had a slow overheat condition. Instead of overheating in 5 minutes it took 15 and a little longer if I was driving it. On my boat there is a scoop on the bottom that forces additional cooling water into the system when the boat is moving. There is a oneway valve that lets water in but not out. It turns out that valve was stuck open, letting about half the cooling water escape when idling or moving slow. I replaced it with an industrial grade valve, and it has worked great ever since. That was a hard one to diagnose. Because on the hose it bypasses that valve. I reworked all the cooling lines. So now everything is good. I am gonna go with new stats, just because there are easy to do now.

 

[Abomb27]

Re: Omc 115 Turbojet stripped down and starting the rebuild

Yeah the idle is high. Manual has it at 1,100 rpms +/- 50. I guess to keep enough cooling water running through the engine.

 

[Abomb27]

Re: Omc 115 Turbojet stripped down and starting the rebuild

After this crazy winter we been having in NY. I cant wait for boating season. I figure two more months. Plenty of time to get my boat ready.