Engine seized 2 miles after rebuild

Merc Cruzer

Merc Cruzer

Well-known member
I just finished rebuilding an engine for my 53 Merc. Had the new block magnafluxed - no cracks. Bored out to .60 over. Reused the pistons, rods, crank and cam. Had engine fully balanced. New rings, berings, and bushings. Fired it up last night and all was well. Took it out for a break-in run today and got about 2 miles and it seized. Oil pressure was 45 lbs at 30 mph. Temp was 170. Was running great until I came to a stop and then it just seized. Tried to turn it over by hand (2’ breaker bar on the front pulley bolt) with no luck. Drained the oil and nothing in the oil. Any suggestions....... before I pull the engine.
 
I can only guess as this point as to possible blockage in the oil line ...the gap was checked at the machine shop after the bore was completed and again when I assembled it....
 
Try to crank it again after it cools down. I had the engine in a 28 Buick do the same thing after running it just a few miles. Pulled it down and everything looked fine. Cranked it back up and just nursed it along for a while and no further problems. Just built a little too snug I guess.
 
<FONT color=#1a1917><FONT face=Verdana>By way of more detail. My old engine was already bored out to .60 +. I had a crack between an exhaust valve and the cylinder so I decided to get a new block. Found the block and had it maganaflux to insure there were not cracks. Decided to reuse the pistons (.60), rods, crank and cam from the old engine. Had the block bored to match the pistons. Had new cam bearings pressed in, used new rings, rod bearings and main bearings. Had the engine balanced. Cleaned up the heads with a .008 cut. Resized the rods. Cut all seats. Installed exhaust seats. New pin bushings. Polish crank. Drilled intake for adjustable lifters. New adjustable lifters.
 
How long between assembly and fire-up? I've seen wrist pins seize more than once due to lack of initial lubrication. We always seem to slather the rods and mains and cam lobes with lots of slick'em but igmore the pins! Or, if it sat a long time after assembly, the oil on the pins seems to go away (Pin oil clearance is so small to start with, there's not much oil to begin with).
 
Time between end of assembly and fire up...about 24 hours. I did pull the plugs and nothing. I drained the oil and nothing in the oil. My next step is to drop the steering linkage and pull the pan and that will tell me where I am going next.
 
before you get to excited, pull the pan and loosen all the rods try to turn engine, if no luck loosen all the mains and try to turn engine, if no luck my guess the pistons or rings are froze up
 
What was the actual piston to cylinder bore clearance after machining? What actual gap setting did you use for piston rings? Who is the piston manufacturer and what material are they made from? I'm thinking machined clearances could have been set too close. I hope the problem can be easily corrected and all turns out well for you. I know this has to be discouraging for you. I once had zero oil pressure at start up on a newly built FH engine and had to pull and dismantal most of the engine to find the problem and then check everything internal for possible damage. This was not my happiest Flathead V8ing memory but there was a happy ending. This engine is now running well and has gone over 6,000 miles.
 
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another thot.....did you have the block drilled and tapped for full-flow oil filter...or the 95% full-flow??...are you running the filter now, if you did??....Mike
 
before you do any thing loosen the starter make sure it is not jamed the eng could of just stalled & when you went to start it the starter jamed it does happen onley takes a few min. to check.
 
Long shot - has the block been modified in the past for full flow filter (passage plugged) and you are running bypass or no filter and thought the passage was open like stock?

Cam bearings - oil drillings lined up?

I think I would be leaning towards careful disassembly, to isolate the cause, to prevent any further damage. Hopefully 99% of the motor is ok and can be reused once the problem is solved.

If it is a valve or lifter siezed then the engine will turn over almost 2 turns then stop and be able to wind back the same amount.

If the cam is siezed then the crank should move very slightly back and forth, just the play in the cam gears.

If all or some of the pistons are siezed, the crank might move very slightly, just the play in the bearings.

If a big end is tight, then very slight crank movement may be seen.

If the crank does not move at all, it is the main bearings that are stuck.

Good luck with it.

Mart.
 
I'd check out the mains and rod bearings. Could be a bit of debris got sucked through an oil passage and jammed one up.
 
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