525 EFI how many hours...
12-16-2013, 10:00 AM
#22
I've had a bunch of 525's in the shop lately. None of them had more than 250 hours. One of them with 210 hours had 6 broken rocker arms. We were just going to replace the springs, retainers, locks and seals. However, there were needle bearing everywhere. We had to pull the engine, remove the intake and oil pan and find all of the needle bearings. Luckily,none made it to the pan. They did make it into the lifter valley. How none went past the cam I don't know. I couldn't believe it.
Another had 191 hours that broke a connecting rod and launched it out of the pan. We pulled the engine to find a 3" piece of rod in the bilge. Needless to say, it made a mess.
All of the others (5) required pulling the heads to change the head gaskets. They all had the composite gaskets and the gaskets were all going between every cylinder. The heads all had low spots between the combustion chambers that required surfacing the heads. None of them would have lasted much longer. All of these engines were pre 2005, so they didn't have Cometic head gaskets. Now, they were all in 2005 and 2006 boats, but the engines were pre 2005.
The ones that do have the Cometic head gaskets also required surfacing. The head gaskets made quite an indentation in the heads. The heads seem to be kind of soft.
The other thing is the springs. They are chicken chit. They only have about 120#'s on the seat. If you plan on running any rpm over stock, you better change the springs. We have been putting 10* retainers and locks in place of the stock 7*. With the stock 7* setup, the install height is extremely short (about 1.820). There really aren't any other springs out there that will go in place of the stock PAC springs, and they are just to light on the seat IMO. The 10* retainers and locks give an extra .100 of install height. That's open up the spring options tremendously. Then you can have a spring with a more realistic seat pressure.
Here are some pics of the carnage.
Eddie
Another had 191 hours that broke a connecting rod and launched it out of the pan. We pulled the engine to find a 3" piece of rod in the bilge. Needless to say, it made a mess.
All of the others (5) required pulling the heads to change the head gaskets. They all had the composite gaskets and the gaskets were all going between every cylinder. The heads all had low spots between the combustion chambers that required surfacing the heads. None of them would have lasted much longer. All of these engines were pre 2005, so they didn't have Cometic head gaskets. Now, they were all in 2005 and 2006 boats, but the engines were pre 2005.
The ones that do have the Cometic head gaskets also required surfacing. The head gaskets made quite an indentation in the heads. The heads seem to be kind of soft.
The other thing is the springs. They are chicken chit. They only have about 120#'s on the seat. If you plan on running any rpm over stock, you better change the springs. We have been putting 10* retainers and locks in place of the stock 7*. With the stock 7* setup, the install height is extremely short (about 1.820). There really aren't any other springs out there that will go in place of the stock PAC springs, and they are just to light on the seat IMO. The 10* retainers and locks give an extra .100 of install height. That's open up the spring options tremendously. Then you can have a spring with a more realistic seat pressure.
Here are some pics of the carnage.
Eddie
Thanks, Andy
12-16-2013, 10:20 AM
#23
Registered
Here are another set that we have now. The tailpipes leaked, causing reversion. The salt water ate the cylinder head from the inside out. Once enough of the exhaust port was gone, the header leaked externally and blew water everywhere in the bilge, causing everything to rust. That entire side of the engine is a big, nasty, rusty mess. Luckily, we were able to salvage the head, since Merc wants stupid money to replace them. After we ground out all of the corrosion, there were areas that required over 1/2" of material to be replaced. We were able to build it back it to where it's as good as new. We had to surface the exhaust face of all 4 heads since all 4 tailpipes were leaking. On top of all the other work and expenses, the tails need to be replaced as well.
I've been meaning to start a thread on them but just haven't had the time lately. If you have a 525, I would check the following:
1-Change the springs, retainers, locks and seals if they are even close to 200 hours
2-Check the rocker arms for failure
3-If they are pre 2005 engines, pull the heads, surface them and replace the head gaskets with Cometics and GM head bolts with ARP's
4-Pressure test the headers
5-You can't pressure test the tails but you can run water through them to check for leaks. Also check the dam in the lower portion of the tail for cracks. If that dam cracks, it will allow water to creep up the pipe
Here are some pics of what happens when the tails leak.
Eddie
I've been meaning to start a thread on them but just haven't had the time lately. If you have a 525, I would check the following:
1-Change the springs, retainers, locks and seals if they are even close to 200 hours
2-Check the rocker arms for failure
3-If they are pre 2005 engines, pull the heads, surface them and replace the head gaskets with Cometics and GM head bolts with ARP's
4-Pressure test the headers
5-You can't pressure test the tails but you can run water through them to check for leaks. Also check the dam in the lower portion of the tail for cracks. If that dam cracks, it will allow water to creep up the pipe
Here are some pics of what happens when the tails leak.
Eddie
12-16-2013, 10:26 AM
#25
Registered
.
muhahaha
muhahaha
12-16-2013, 10:43 AM
#27
12-16-2013, 10:48 AM
#28
Registered
There is no rhyme or reason to the failures. From what I've seen, run time and rpm amount has nothing to do with it. I can tell you that the valve springs absolutely suck ass. They are too weak and loss pressure too quickly. Both the headers and tails need to be looked at on a regular basis. Other than that, I can't tell you why they fail.
Eddie
12-16-2013, 11:15 AM
#29
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thx for the info Young Performance.... I think i am going to buy a shiny new cedar strip canoe!!! I can't afford to buy another boat.. then drop another 25 K to rebuild engines.... and with my luck if I didn't touch them it would have only been a bad timing chain.... LOL
