Rebuilding Motor - Need Advice and Parts

[GKricheldorf]

Let me give a little prior info.

Well I took the Z-25 out for a spin two weeks ago to test out some props. All seemed fine until I gave the boat half throttle leaving the harbor. After no change in rpm or speed I gave it full throttle. Still nothing….. So I idled over to the jet ski area and started pulling plug wires while the boat was idling. I’m not a big fan of getting shocked, but I did it anyway. Turns out cylinders 1, 3, and 5 were not firing. So I went and got some parts (wires, rotor, and the distributor module) from the marina store and put them in – still no change. I decided the day was over and loaded the boat back up. Took it home and did a compression check.
1- 65 psi
2- 110 psi
3- 0 psi
4- 115 psi
5- 0 psi
6- 120 psi
7- 115 psi
8- 120 psi

After talking with a few friends and family that are mechanics I was instructed to remove the valve cover. Well that was an unsightly ordeal. 4 push rods were broken and lots of rust and milky oil. I then removed the head. The smaller valve on cylinder 3 was stuck open – I guess it is bent, but didn’t remove it yet. I also found the rest of the broken push rods after removing the intake manifold. I then removed the other head, but other then the rust and milky oil it looked fine.

Now I’m no mechanic by trade. I own an 82 CJ7 and I’m always breaking something while off-roading and I’ve always taken stuff apart to see how it works since I was a kid. So I know I can handle this. It’s just so basic and I just can’t pay someone to do something I can do.

So now to my questions.

Are any of you guy’s parts dealers? My engine is the Merc 454 MAG Alpha. I looked up all the parts and gaskets I need to replace and it looks like it will be $ 700 - $750. Can I get a better deal somewhere else?

Should the parts I replace be stock? Or go a little more high performance? Roller Rockers, Roller lifters, better push rods, etc…. This is where my lack of knowledge gets me. I just don’t know.

[MOP]

Hope no one read my deleted post before I read this one properly! For where you are thinking of going, opinion pull it and do it over the extra bucks spent you will start out fresh. No telling what else will show up if put back together without a tear down and cleaning. I doubt if you do it with maybe high lift rockers and full rebuild that you will go uch over a grand back in the hole and running. Shop Ebay for parts!

Phil

[GKricheldorf]

I'm just wanting to get my boat running properly. I can use the factory stock parts, but was thinking there are better parts for a little more money that just cut down on the wear and tear and give a little performance boost. I know some of you guys put big bucks into your boats because it is your hobby. My problem is i have a couple hobbies and need to spread the wealth across them all, what little wealth there is.

I also had a chat with a buddy who is a hot rod buff. He asked me a bunch of questions on how the engine looked after i tore it down. He said i may have thrown a bearing. Is there a way to check that without having to remove the engine from the boat or am i just wishfull thinking?

Thanks for taking the time to read and answer. I'll get some pictures loaded up this evening.

[MOP]

In order to get any close answers need all questions answered, was the engine laid up for an extended period. Is there milky crap on the dip stick. The push rods may have been broken by hydraulicing the engine, to many variables. If it has a fair amount of time on it rebuild it


Phil

[GKricheldorf]

Me and a buddy picked up the boat last season. I think we probably put 100(316 total) hrs on since. The only times it sat for an extended period of time was late October to mid January. When we took it out in Janurary for a day and it ran rough. I was thinking that gas may have turned since i forgot to put an additive in it on a full tank. So when i got home i pulled the plugs and put in some new ones and replaced the fuel/water seperator. For the most part the plugs looked ok, but there was a little rust on a few, but didn't make note on what cylinders. So it sat again from mid Janurary to two weeks ago.

Other then the boat running on 5 cylinders two weeks ago and the rough running in Janurary we never felt, heard, smelled, etc that there was an issue about to happen. I could, before i tore into it, start it up and it would idle @800 rpm with no problem. The only concerning sound i would hear was maybe it needed the valves adjusted(reccomended by dad), but that was it. No broken, grinding metal sounds.

I didn't see milky crap on the dipstick. I also was expecting the oil to be darker then it was when i checked it from time to time, but not the same color as it was when i pulled the head off. I'm pumping the oil out tonight to see if there is any metal fragments in the oil.

[MOP]

Ok rusty plugs need immediate attention not suppose to have any rust. My thought water got in and caused the problem only pulling it apart will tell you how much. May need to add pistons to the bill, cylinder walls corrode very fast and if run they can get pretty bad.

Phil

[Jamesbon]

Sorry to hear the news.

While you're at it, check those exhaust manifolds for water leaks. ...I wonder where the water entered the engine.

[GKricheldorf]

A couple of things come to mine on how the water got in.

1 - was like that when i purchased the boat
2 - having the water running from the hose without the motor running - i didn't know this was bad, so when i would be tinkering on the boat i would leave the water running instead of jumping out of the boat to turn the water off and on.
3 - I don't have those rubber flaps on my thru hull exhaust, but i'm gonna get a pair
4 - ???? maybe a cracked head

There are no visible leaks on the outside of the motor to tell me there is a problem.

[Jamesbon]

GK,
1) okay
2) "hose running" shouldn't matter if everything's kosher
3) no flaps is usually allright, assuming your exhaust outlets/pipes are mounted high enough and at a "sufficient downward angle."
4) a good possibility

How did your head gaskets look? One can usually spot a faulty block/head seal by rust or some type of nasty looking or non conforming color around that "stainless" ring which seals the cylinder between the head and block. Specifically, check those cylinders with "0" or "low" compression.

Did the cooling water in the engine "freeze" at anytime during the winter? (I'm not sure what climate the boat is stored in)

Hope that helps...

[GKricheldorf]

Mr. Bon(d?)

The exhaust outlets are at a good angle above the waterline.

I'm going to post some hi res pictures this evening. I just don't have the triained eye to spot something that might not jump out at me, but will take a closer look.

I live in So California - no freezing here

[DONZI]

If you have broken/bent 4 push rods.You are going to have to take a good look at the camshaft lobes & piston tops.Chances are a partial rebuild maybe not an option.Seeing as you have the heads off.I would bring them for a rebuild total estimate which includes magnufluxing them for cracks. In order to ck.the bearings this will require oilpan/ engine removal.If the valve springs were rusted and engine over revved.This may have resulted in the valves getting to know the pistons. Hence the damage.You will have to locate the water source though.

Hope this provides some insight.

[Woodsy]

G...

Being in Cali I assume this boat spent most of its time in salt water? More than likely with this kind of damage, I would be seriously looking at your exhaust manifolds. Sure sounds like the engine hydro-locked, that is got water into the cylinders and seeing as how water doesn't compress...

In any case, with this much damage, I would opt for a a complete rebuild or maybe try to score a cheap crate motor or takeout. You just don't break pushrods... they usually bend, and bent valves usually indicate that the piston hit them. I am going to go out on a limb, but I'll bet the only thing your going to salvage out of this motor is going to be the accessories. Don't try to do this one on a cheapo rebuild, you'll end up paying to do the job twice. I seriously doubt your going to get away with a valve job & cam change...

Sorry for the bad news... I hate when this stuff happens

Woodsy Von Outboard

[Ed Donnelly]

When you had it on the hose, was the tongue up, or, resting on the ground. If the tongue was on the ground, the water ran back through the exhaust and into the clinders via the exhaust valves. How do I know you ask? Well I don't have a twin turbo in my Criterion anymore....Ed

[GKricheldorf]

Woodsy - I have taken it out in the ocean many times, but the boat was from the east coast. There is a Vermont sticker on the window and the guy i got it from said he had it out there when he lived there.

Ed - The tongue was never on the ground, but my driveway is at a slant and i back the boat in and park it so the engine is on the high side with the nose pointed down. Hmmmmm

I'm trying to upload some pictures, but i think they are to big. I'll keep trying

[GKricheldorf]

Here are some links to some pictures. These are larger images and would not upload to this board.

http://www.wholesaleauction.com/partimages/donzi/head-3-1.jpg

http://www.wholesaleauction.com/partimages/donzi/head-7-5.jpg

http://www.wholesaleauction.com/partimages/donzi/pistons-5-7.jpg

http://www.wholesaleauction.com/partimages/donzi/pistons-1-3.jpg

more to come

[GKricheldorf]

http://www.wholesaleauction.com/partimages/donzi/intake.jpg

http://www.wholesaleauction.com/partimages/donzi/rocker-arm-5.jpg

http://www.wholesaleauction.com/partimages/donzi/rocker-arm-1.jpg


http://www.wholesaleauction.com/partimages/donzi/valve-cover-removed.jpg

[gcarter]

When I bought my Minx The SBC looked similar, except One Piston was frozen w/ the rings rusted to the cyl. walls. Stuck valves, bent push rods, same cyl. I finally determined it must be the intake manifold, but I never actually found THE spot. Engine had been rebuilt and the intake manifold had been changed. Frustrating! :banghead:

George... Always the sucker for the bargain!

[Donzigo]

Ditto on what has been said. Woodsy is right on...........my money, given the information presented says a new engine is going to be the cheapest way out. Salvage the accessories. Water in engine, doesn't matter how, is never a good sign. If you can tear it down yourself, do that first, to satisfy your own self that a new engine makes sense. Exhaust manifolds have been known to last about over 1,000 hours, if the boat is used EVERY DAY, (as in my buddy's parasail operation here in St. Pete, his engines run every day for hours and hours). If your boat was used by the previous guy sometimes and not properly flushed at idle for 10 full minutes, big problems, & the exhaust manifolds might only last 100 hours. My general rule of thumb is 3 years or 400 hours, better check those bad boys out. That's probably where the water is coming from.

And yes, your pictures are mammoth. Try resizing them with Photo Draw or Corel then resend them.

[GKricheldorf]

After closer examination last night at the exhaust manifolds i found that one of them had the wrong gasket on it. I have the risers pictured below. The riser on the working side of the engine had a restricted gasket and the non-working side of the engine had the non-restricted gasket. Can this be part of my problem?



Dennis Moore - i copied some of your pictures to help explain what i have. Hope you don't get mad :( - but i will be buying your aluminum manifolds and risers :)

Below is a picture of my risers and the gaskets. My risers had one of each gasket.

Donzigo - i did that so that you guys that actually know what you are doing, unlike myself, could get a closer look at my delima and maybe spot my probpem. I'll probably spend the money on a new engine. I may have a line on a long block for about $2600