89 200hp rebuild

[andy6374]

Re: 89 200hp rebuild

Like reeldutch said, you have to figure out what caused the engine failure or history is bound to repeat itself . Posting some pics or emailing Dhadley with the pics would help. Usually by just looking at the piston and cylinder walls, one can get a decent idea what caused the failure, wheather it was a lean carb or an overheat, etc...<br /><br />You will be replacing the waterpump and tstats, as well as rebuilding the carbs and fuel pump, so you will be able to see if the carbs are gummed up or if the impeller was shreaded.<br /><br />It would be great if you could post some pics of your progress along the way. I know I and others would love to see an engine rebuild and in fact I wish people did it more often. You can upload your pics a www.photobucket.com and then post the links here. If you are interested I could walk you throught the process of posting pics.<br /><br />Good Luck

 

[Dhadley]

Re: 89 200hp rebuild

The OE for the .020 piston & rings are 439015 & 439016 I believe. I don't think BRP has a .040 piston.

 

[JonLewis]

Re: 89 200hp rebuild

Thanks for the help guys. I took the motor down to my dad's house (he is a retired car dealer mechanic) so that he can work on it. He has more time than I do. So the block is here anylonger for me to take pics. I will try and have him take some, but he is not very good or trusting with the internet. He knows the boat dealer mechanic pretty good and they were concerned that the pistons would not fit because his book did not show them as being interchangeable. I am not saying you are wrong-I have seen on this board how knowledgeable you guys are-but sometimes it is hard to get people to be trusting of something they are not familiar with. I will try and get some pics of what we have done so far and also try and get some of different steps of the reassembly. We will be going through the carbs and checking the water pump/thermostats and also checking out the vro system. Again I cant afford to take chances and not go the extra mile, so just keep making suggestions. Jon

 

[reeldutch]

Re: 89 200hp rebuild

so who's reboring the block????<br /><br />my advice is still find a machine shop who will provide you with the pistons.<br /><br />and yes you cannot trust anybody on the internet.<br />dubbelcheck everything.<br />its a good habbit.<br /><br />are you wuried the pistons will not fit on the rod ??????<br />i dont understand their consern???

 

[Dhadley]

Re: 89 200hp rebuild

The book will have them as 2 different part numbers because they are 2 different pistons. You can use the newer pistons (93 & newer) in an older (88-92) block but you cannot use the 88-92 pistons in a 93 & newer block.<br /><br />You cannot mix the 2 styles of pistons although you can mix sizes of either style. <br /><br />You can mix the forged Wiseco (.040 os) with the OE cast pistons as long as you use the same style. If it were me I'd put in all 6 Wisecos. In fact we're building that same motor for a little boat we're gonna race and that's exactly what we're doing.

 

[JonLewis]

Re: 89 200hp rebuild

what are the benifits of the Wiseco? What are the benifits of a forged piston over cast in a marine application? Will it add to performance or just add to the strength? The price seams to be 30-40 dollars between the 2, is it worth 200? I am considering buying the wiseco, I just want to make sure that there is a reason for the difference. I am definitely boring all cylinders-5 of them .020 and one .040. One cylinder had already been bored to .030 thus the .040. The machine shop wants to charge me about 100 per piston kit and iboats has them for 79, that is why I am leaning towards not having the shop get them. Do you have a part number for a wiseco .020 and .040 with the wrist pin, circlips and all?

 

[reeldutch]

Re: 89 200hp rebuild

they should be in here<br /> http://www.pistons-online.com/marine.asp?make=OMC&bg=415&ed=425

 

[Dhadley]

Re: 89 200hp rebuild

The Wiseco series part number is 3143. You'll need port sides (3143P) and starboards (3143S). Then the bore size after the P or S.<br /><br />If the .040 piston is on the port side the part number will be 3143P4. 3143S4 if its on the starboard. Then 3143P2 and 3143S2 accordingly.<br /><br />The forged piston will be stronger and quieter but the OE doesn't have the .040 os anyway.<br /><br />List price on the 3143 is 109.64. That's for the piston, rings, pin and locks. You can go to wiseco.com and check out the marine catalog.

 

[Dhadley]

Re: 89 200hp rebuild

The other thing that comes to mind is the cylinder thats already bored. If it's at .030 now that means there was at least 1 problem, maybe more, on that cylinder before. Now its tore up again. We need to find -- and fix -- the cause.<br /><br />A damaged cylinder or piston is not the cause. Its a result.

 

[JonLewis]

Re: 89 200hp rebuild

My dad called me and told me that the only thing that he has found so far is that the seal rings that go around the crank were worn out. Would this have caused a problem with the cylinders/piston? We have gone through the carbs and didnt find any problems. Are there any other areas that we should look?

 

[Dhadley]

Re: 89 200hp rebuild

Describe what you mean by the seal rings were wore out. Thats not typical at all.

 

[JonLewis]

Re: 89 200hp rebuild

He said that he thought that they are called crankcase seal rings and that they look like a piston ring. The thickness of the ring looked worn down, like there was to much endplay in the crankshaft. The local shop had to special order them.

 

[Dhadley]

Re: 89 200hp rebuild

These rings shouldnt wear at all. That's why nobody stocks them. Dont go by what they look like. Is the surface in the block and front half OK where they ride?

 

[JonLewis]

Re: 89 200hp rebuild

Well I was down by my dad's house this last weekend. On the block where the rings sit looked ok, but to be sure we took it to the shop to have them check it out. They said that it was ok. Yesturday my dad called me and told me that he found that one of the old pistons was put on backwards. He said the spit hole was on the wrong side. What kind of problems would this cause? I would assume that it would cause an intake and exhaust problem. By the way, I did end up going with the wiseco pistons in the newer style.

 

[Dhadley]

Re: 89 200hp rebuild

What is the "spit hole"? Are you talking about the oil hole in the rod? If so, that won't matter. We've seen the pistons on the rods backwards and the oil hole pointed down and it ran for years with no problems. As long as the piston is in correctly it wont matter. If the piston is installed backwards, one of the ring gaps will end up in the exhaust port. It wont last long at all like that.<br /><br />If you use the newer style pistons, make sure all 6 are the new style. Dont mix them.

 

[JonLewis]

Re: 89 200hp rebuild

We have looked at the rod and piston to try and be sure but there is no way to be sure how it was in there. Before removing the pistons, all of the rods were marked on the side. During reassembly, the one piston was backwards and the numbers were marked on the correct side. Either the piston was in backwards or the numbers on that one rod were put on the wrong side. Either way, I dont think that we can be 100% sure. <br /><br />The power head is completely back together and back on the boat. What is the correct break in procedure with a rebuilt? The vro is disconnected so what fuel ratio should be used for breakin and after?

 

[Dhadley]

Re: 89 200hp rebuild

If by the "spit hole" you mean the oil hole, it always goes up. There is a "bump" on the rod and one on the cap. Those have to line up. They end up facing up also.<br /><br />The correct break-in will be determined by the machine shop according to what they used for a skirt to wall clearance.<br /><br />I'd highly recommend updating the oil injection to the OMS system and using it. The motor requires 50:1 mix and most shops double it for break-in. Again, that will be determined by your rebuilder.

 

[phatmanmike]

Re: 89 200hp rebuild

25:1 for break in.

 

[JonLewis]

Re: 89 200hp rebuild

We are sure that we have the rods and pistons on correctly now but the 1 piston rod combo was definitely not on correctly. Whether the piston was in the cylinder correctly we are not sure. I spoke with the shop and they also said 25:1 for break in. What does the OMS update consist of for the VRO system?

 

[Dhadley]

Re: 89 200hp rebuild

Its a different pump. Looks basically the same but has 4 wires and better warning. It's not a variable pump but rather a constant 50:1 (more or less). All the hose routing and brackets are the same.<br /><br />Most likely the rod was in upside down before. If the piston was in upsidedown one ring gap would be in the exhaust port. It'd last a matter on minutes.