Risers

"Was Wondering if anyone could

"Was Wondering if anyone could share some thoughts on a Lube oil Analysis I just got back from a engine survey. As part of a pre purchase inspection I had an analysis done on a pair of 454 crusader engines installed in a 1992 31 tiara. The owner said the engines were re-built in 2006 and there are only 200 hours on them since. The boat is in beautiful condition and the boat ran great and acheived 4000rpm each side. The problem, however, is the analysis on the starboard side showed high sodium readings (194 ppm) and above average readings for silicon (26 ppm), iron (170 ppm) and tin (10 ppm). The Port engine showed high signs of sodium (174 ppm).
My question is the most likely culprit bad risers or possibly faulty riser gaskets? Could it possibly be evidence of a larger issue such as blown head gasket, faulty heat exchanger? We got up to 28 knots at WOT and had no problems throughout the throttle range during sea trials. Any feedback would be greatly appreciated.
If it is the risers, how much am I looking at cost-wise? I've researched it and it seems like to do the risers myself with Osco replacements I'm looking at a grand. Am I missing something becuase all the estimates I see on the site regarding this, seem to point to the 2000 dollar range. Again, any input would be wonderful."

"Chris,

In my opinion, that

"Chris,

In my opinion, that 2000 mark is likely for manifolds and risers. I did both engines at around 2000. By the time I solved the problem, it needed valve jobs on all 4 heads as well. I THINK the cost per riser was about 120. I have the same 1992 Crusaders. If Fresh Water Cooled with gaskets, blockoff plates and a few ancillary items...MAYBE 600?? MY OPINION ONLY ! My oil analysis showed ALL of the elements of antifreeze too...Yippee !

BTW: All the time these things were getting worse...those engine APPEARED to be running GREAT...Never showed any sign of a problem "

"Chris,
First off welcome to

"Chris,
First off welcome to the forum. Right off the bat I notice your WOT rpms are a little low. You should be operating at 4600 +/- 200 rpms. Might be improper prop sizes or engines not fully tuned. Either one puts more stress the engines.
Regarding your analysis what did the report say specifically about the contaminates and possible sources? What exhaust components did the previous ower change with the rebuild? Normally a leak in the risers/elbows will be a raw water leak into the exhaust manifold and in through the valves resulting in compression lock. The only gasket that could potentially leak anti-freeze is the the gasket between the exhaust manifold and the risers. That is even tough because there is a stainless steel block off plate installed there (supposed to be anyway). That joint has exhaust manifold/gasket/blocking plate/gasket/riser. If anti-freeze is getting in there then maybe you are missing the blocking plate somehow.
Other areas to consider would be head gasket leak. How's the compression? Was a leak down test performed on the cylinders? Sometimes rebuilders will use non-marine gasket sets to save costs."

"Thanks Guys for the welcome a

"Thanks Guys for the welcome and the information. I thought the RPMs were a little on the low side but the surveyor said given the year they were within an acceptable range (4000-4500) at WOT. I didn't have a compression check done. Based on how it ran I didn't feel it needed it. I wasn't so in love with the boat that I was blinded and unaware it's just that It ran so smooth and so well and hopped right up on plane I figured all was well. Truth be told, had I not done the oil analysis I probably would have been blissfully unaware. Glad I didn't. So it seems like the risers may not be the issue and it could be a blown head gasket. I guess the ultimate question is should this be a deal breaker. The owner is willing to come down 2k on the price as long he doesn't have to deal with it. I'v only had mercs in my boats and this is my first foray into crusaders. Any further advice will be greatly appreciated seeing as I'm totally udecided about what to do. Thanks for any further input"

"If the rest of the boat is ac

"If the rest of the boat is acceptable and you have an interest, why not ask to see if there are any previous oil analyses. The trusted sources available to me say that the trends shown in the reports are much more telling than any single sample, especially if the sample wasn't obtained correctly.

What did the report you have indicate about the worry areas?"