Newly Rebuilt Engine Stalls - Why?

J

JoeTallyHo

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2001 Four Winns V298, VP 5.7Gsi Duo Props. 451 hours and northern Chesapeake Bay. Port engine rebuilt last Oct 2012 after knocking noises in lower engine and one low compression cylinder. All new risers, exhaust manifold, cylinder heads, and thermostat housing. After successful sea trial, boat boat was winterized and hauled. First run of season 3 weeks ago. Only about 20 minutes on plane. All OK then.

Yesterday was 2nd run of season and about 15 min at no-wake speed and 10-12 minutes on plane, I noticed port oil pressure had dropped to around 25 psi . Before that, all normal at around 45-50 psi. Stbd running a little higher at 50-60. Steady. All temps normal at 160 degrees..

Then, I had to increasingly add more port throttle to keep engines synch. at 3200 rpm. but port RPM kept dropping, Then about a minute later, engine stalled. I turned ignition off. 5 minutes later tried to restart, no go. But noticed port temp skyrocketed to about 210 degrees. No engine alarms,

Back at dock, inspected engine and did not see anything unusual. Port engine was noticeably hotter than stbd. Checked oil. Port dipstick showed oil was greenish. Stbd was golden brown. I had not checked oil since the engine rebuilt, so do not know if greeniish was there before.

The mechanic said he ran break-in oil for about an hour and
changed to normal oil. i did not hit anything, no grounding, and water too cool for any slime or vegatation growth.

Any ideas here?

Thanks - Joe
 
Lotta possible problems. What bearing was causing the original knock? Find out. Spun bearing is a possibility but oil pressure usually stays low...like 3 PSI or less unless RPMs are kept high which will increase damage from spun bearing. Was there audible knocking?

Antifreeze in the oil is an indicator of overheating resulting anything from warped or blown head gasket to cracked head or block.

Was old block used for rebuild? was it magnafluxed an/or sonic tested? Was oil passages all opened and cleaned out? Some rebuilders only replace a few components. A bottom end knock from a spun bearing sends lots of metal through-out engine, blocking oil galleys and causing another spun bearing.
 
You might as well call the Re-builder and let him do the trouble shooting.
 
Its bad when a drop in oil pressure correlates to an increase in temperature. Next symptom is to note which follows which. If oil pressure follows temp increase, the root cause is generally cooling. If temp follows oil pressure (as your case seems to indicate) then lubrication is the problem. Another spun bearing is likely causing the loss of lubrication, resulting in heat. Cooling related may be a top end rebuild, but lubrication related means a likely bottom end rebuild. Almost does not matter the cause, the repair is essentially the same. Another block renewal.

For sbc engines, I've become more of a believer in quality crate long/short blocks than in rebuilds. Especially for marine. It's hard to find a marine rebuilder of quality who can compete with the cost of the quality crate solutions, especially since its unusual in marine engines to want to do a lot of horsepower building specialty things you might do to an auto engine. Marine engines want reliable torque and that's more about good solid rebuild quality and not so much the tricky stuff we put into high hp auto's. Thus, my favorite engine rebuilder for my project car will almost certainly never be asked to rebuild my boat engine. Tried that once. Was a waste of money and ended up ordering new crate engine a few years down the road. Can't beat economics of SBC crates in the marine business. Just can't. If you can, start wondering why your rebuilder charges so much less than everyone else.

Sucks, but if you own boats long enough you become familiar with this story. Rebuilds take weeks, new crates can be on the doorstep in days an only a solid 1.5 days of R&R to move accessories and have it put back. What's your summer time worth? Just sayin. Shops sometimes like to rebuild because they then theoretically make money on the rebuild time too. This only makes sense in the off season when they are under capacity, but often the knee jerk response carries into timelines you don't want. Insert yourself into the equation to maximize your results.
 
Thanks for all the comments. What is a spun bearing?

The green oil turns out is the color of the break-in oil used.

Initial mechanic report is the computer codes report both low oil pressure and high temperature. He cleared the codes and was able to restart engine. Codes again indicated low oil pressure, but no high temperature.He also reported a low end knocking noise. I guess he did not let it run that long to wait for the high temperature.

General mgr is starting to stake a position that high temperature came first and, if true, no warranty. BS! But, I reported to her all temps were normal leading to the shutdown and high temperature only showed when I attempted to restart the engine a few minutes later.

I think the manager knows it is a warranty issue and seeing she has to cover the costs of having the enigne rebuilt again or get a brand new engine, is trying to position that this damage is not under warranty. I told her it was clear to me that with less than two hours, something was not done right and this should be under warranty. She said they still have to take apart the engine to find out more. Should they even bother? and just go with a new engine?

This is my original engine block rebuilt. Would all attached new hardware be in good condition to be put on another new engine in this situation?

Joe
 
Its short for small block Chevy, 305 or 350 it goes on and on. As a Engine builder it sounds as if the engine was starting to tighten up. As one stated spun bearing on the main or rod journals of the crankshaft. The main and rod bearing have a tang that sticks out of the side of each bearing to hold them in the main and rod caps and also into the Engine block. When a bearing spins it turns in it bore which closes up the oil hole in short it goes boom after that. When you hear of someone Blowing a Engine (rod thur the oil pan or out the side of the block) 9 times out of 10 it spun a bearing or something first a rod just doesn't break, it gets hot and then breaks. If I read you post correctly It was getting tight that is what made your temp go up and the oil pressure to go down. You were having to open the throttle more and more. It's was good that you even noticed some wouldn't. The hotter the oil the thinner it gets which is why you loose oil pressure. Tell them to pull it down I'll bet you are going to find the bearings chewed up and the crank ruined along with a rod or two. If so with out a lot of machine work it will need another engine not saying it cant be repaired. But I feel it was put together to tight ( not enough main or rod bearing clearances)If they are going to repair it I would not let them use the rod again if it spun a bearing because its been to hot (metal fatigue) A turned crank is ok as long as its not 30 thousandths or more 10 or 20 will be ok. it will also need to be line honed. What I'm saying is don't let them BS you make them show you what happened and ask why it happened the parts will tell you the story. If I can help you message me. Jamie Wheatley ,Wheatley Racing Engines Richmond Va.
 
P.S. If they repair or replace you engine make sure they flush all the oil lines very very very - good better yet replace them its really tough to get all the metal out. Just sayn :)
 
quote:
Originally posted by JoeTallyHo

Thanks for all the comments. What is a spun bearing?

The green oil turns out is the color of the break-in oil used.

Initial mechanic report is the computer codes report both low oil pressure and high temperature. He cleared the codes and was able to restart engine. Codes again indicated low oil pressure, but no high temperature.He also reported a low end knocking noise. I guess he did not let it run that long to wait for the high temperature.

General mgr is starting to stake a position that high temperature came first and, if true, no warranty. BS! But, I reported to her all temps were normal leading to the shutdown and high temperature only showed when I attempted to restart the engine a few minutes later.

I think the manager knows it is a warranty issue and seeing she has to cover the costs of having the enigne rebuilt again or get a brand new engine, is trying to position that this damage is not under warranty. I told her it was clear to me that with less than two hours, something was not done right and this should be under warranty. She said they still have to take apart the engine to find out more. Should they even bother? and just go with a new engine?

This is my original engine block rebuilt. Would all attached new hardware be in good condition to be put on another new engine in this situation?

Joe

Click to expand...


My prediction is that they will try to weasel out of the warranty. Demand to be present during the tear down and take lots of close-up pics of the main and rod bearings when they pull the caps. Be prepared to file a warranty case with the proper town quickly in case they renig. Good thing is that your new exhaust parts will work fine on the replacement engine.
 
in todays world its cheaper and always works out better for the owner to install a new long block we do not mess with any rebuilts period
 
Back a few decades I owned a WellCraft Scarab 1. I brought the boat up from Florida on it's trailer to NJ. It had a rebuilt 454. I took it out in the Delaware River and with less than an hour on it, it almost seized. It lost oil pressure and had a rattling sound. Turns out I lost crank bearings and the top of a Piston. To make a long story short the Philadelphia builder rebuilt it 2 times before refunding my money. Then I took it to a friend that was an excellent wrench. After disassembling the engine he took the oil pump off the block and showed me a washer was loose behind the pickup. It turns out whenever I would get on the throttle the washer would close off the oil to the input of the pump. I ended up replacing the engine with a complete long block. I never had another problem with the motor again but I only kept the boat for a few months after the long block was installed and sold her.
This was one of the strangest things I have ever seen and I doubt it's your problem. It does show the shortcuts a re-builder (actually 2 re-builders) took.
Bill
 
When a bearing pins, it wears the lead bearing surface in seconds. Then it steel on steel which quickly starts eating the main or rod journals. This creates a large gap for the oil to escape. All the oil flows out (path of least resistance) and that's what causes low oil pressure.

Repeating what I said and what Jamie said, if they didn't open the oil plugs and clean out the oil galleys, it will prevent full lubrication of the engine.

A little FYI for those interested in oil distribution of GM engines.
The oil pump is attached to the rear main bearing cap. Oil goes up the pump to a horizontal galley in the back wall and runs to the oil filter. From there it returns to the rear cam bearing. The rear cam bearing is the distribution point for the whole engine. There are 3 oil galleys running forward the length of the block. The two galleys on either side of the cam bore lubricate the lifter bores and up to the rockers. The galley above the cam lubricates the full length of the cam and each cam bearing in turn, feeds downward to the main (crank)bearings. The cam lobes are lubricated by oil escaping down the lifters bores and by splash from the crank counterweights. I left out a few things about how the oil travels. If anyone is interested, ask.
 
UPDATE - Guys - Thanks for all the detailed information. Great stuff!

Armed with all this, I think the manager of the servicing marina is agreeing it is a warranty issue. Their normal M.O. is to tear down and troubleshoot, but thanks to you guys I told her to wait. They took the oil filter to the machine shop technician and he did not find anything. But did not know if they tore down the filter or just drained the oil in it. Then they restarted the engine with my mechanic and the machine shop present. No low oil pressure this time (showed up when he started during initial code check).

However, they both heard knocking noises, then recommended removal of engine for further troubleshooting. I called the manager to tell her to give me a quote for a new engine and not do anything else.

This whole episode started last fall when my boat could not get on plane at WOT (451 hours/11 years). 3 cylinders on stbd engine read 0 on compression test, 1 cylinder on port read 25. They found pieces of impeller in the stbd and all 4 cylinder heads were cracked. Replaced stbd with new VP Long Block and rebuild port.

But, initial repair for port was only replacing cylinder heads, manifolds, and risers. Upon initial testing, they heard knocking noises in the lower part of the block and they had to pull it again. And it was decided to rebuild the port engine. They only charged me for the actual rebuild and not the second tear down, removal, and reinstallation of rebuilt.

All this to say, I have the actual charges for a new Long block and rebuilt engine.

I told the manager I was willing to pay the difference between a new engine and a rebuilt engine, all other labor and parts necessary to complete the job should be covered under warranty. I thought this was fair. She is working up a quote. Based on the original charges, this delta comes to about $2,600.

By the way, it was mentioned above about "tightness" of the rebuild. Could this also be caused by the re-installation of the engine not being properly aligned? They do about 5-8 of these jobs a year, is alignment difficult and tricky for an experienced mechanic?

Joe
 
Alignment would first chew up the trans seal and you would feel a lot of vibration. You would get further noise as the cutlas bearing self destructs. I would expect a lot of other bad things before alignment could cause an engine failure.
 
Tightness in the rebuild is the internal clearances, usually the main bearings but also includes the valve guides. As part of the rebuild the crank is machined to give a smooth finish and round profile. This results in a slightly smaller diameter which is compensated for by thicker bearings. The rebuilder needs to fit bearings that are correctly oversized to give proper clearance, too tight and insufficient room for an oil film to lube the bearing. Too loose and you will not get a full service life as it starts out "worn". A tight rebuild will put torque on the bearing and spin it in the housing. Once the bearing rotates in the journal the hole on the bearing no longer aligns with the oil galley output effectively shutting off the oil to that bearing, the bearing then overheats, softens, galls the crank and comes apart. As it comes apart the oil then free flows out of the galley and pressure drops, then all the bearings are running dry and it's quickly game over.
 
Just my opinion , but let them tear it down you may get a new engine once they find the damage to yours. Just by what you described it has spun a bearing or gaulded a piston I may be wrong but I am going by what you have stated happened. If its warranty and you have paid for the job, most company's will try to make it right when they find out they caused the problem. It would be worth the cost to take them to court if you had to. BUT TAKE PICTURES WHEN THEY TAKE IT APART DO NOT RELY ON THEM !If it was something you did they are going to laugh at you. And I did say most company's not all. Jamie
 
Final UPDATE!!

Thanks for all the great comments and suggestions. Armed with this information, my marina agreed to replacing the engine and me paying only the difference between the rebuilt engine (which died) and a new long block. Marina did not charge for labor to remove rebuilt engine and install new longblock. Still about $4K more, but worth much more in peace of mind.

The part of this story I did not tell is that my stbd engine was replaced with a new longblock because of water impeller clogging water cooling passages in the cylinder head causing melting of the block around two cylinders. So now I have two new VP V-8 long-blocks. Only computer, intake manifold, alternator, power steering pump,starter, fuel cell are original since 2001.

Only seatrial issues was an erratic oil pressure gauge solved with replacing oil pressure gauge sensor/sender. Other issue is WOT getting on plane stbd engine runs about 2000 RPM slower (according to synch RPM gauge). At other throttle positions, when synch is 0 RPM, both throttles are in same position. Not sure if this is another problem I should worry about.

Also, the mechanic never heard from the machine shop on what caused the port rebuilt engine to fail, two months later.
 
FWIW , here's George VP's perspective on rebuilds:
http://www.boatered.com/forum/topic.asp?TOPIC_ID=122789

Since you haven't mentioned it , have you been following a break-in regimen on the rebuilt and now new longblock engines? With latest engine materials there ...may... be need for somewhat less break-in but I figure if that is neglected when brand new, it's not going to do a bit of good to try and go back to do it later.
http://www.boatered.com/forum/topic.asp?TOPIC_ID=51384

Are the tachs agreeing with the sync gauge when going on plane? Is this strictly a passive sync gauge , or possibly an active sync system with which the slave engine's rpm may have a bit of a lag over the master's when accelerating?
 
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