Think Im going to be sick. brand new flathead siezed.

Was your crank fully cleaned out. I had one dislodge some crud when reved up. Completely destroyed all the bottom end bearings in seconds. Like you I was gutted. Cost a lot of money and time to fix it. Wheh I asked my machinist if he cleaned out the crank the reply was I thought you did. I triple check everythig now. Hope you are on the road soon.

 

Exactly what I was thinking....

Rat

 

Different eng but same experience. I had one seize after 20 minutes running at break in. The main was just a tad too tight and the opperating temperature expansion did it in. I was able to wet sand the crank with 400 grit and put a 1 thousand over and it's running great.

 

Sorry to hear about your flathead woes, please keep us posted, so we can all learn something from this. Someone mentioned walking away from it to get your head straight, great advice, that works for me. Good luck

 

Have you pulled the dipstick to see if there is metal in your oil? A quick check.

 

You have probably already tried it but can you turn the crankshaft backwards? I doubt that a flathead could eat a foreign object like a bolt or nut and get it on top of a piston but stranger things have happened.
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Ouch. Flathead, double ouch. Good luck man, looks like you got some good support on here. Keep us posted, im interested to see what it was.

 

I'd start pulling external parts that could do it first. Sounds like you know how to build, so it could be something else. I bought a 69 buick skylark with 33,000 miles on it because of a locked motor. I put my breaker bar on it with a cheater pipe and my 250 lbs. of weight and jumped on it, thinking I could'nt hurt it any worse, because I already had another motor in mind, but it let out a loud ping and rotated smooth. Checked the engine out and all was well, got under it and pulled the starter and what happened was the starter gear over ran the flywheel and jamed the engine tight. Rebuilt the starter nose and drove perfect like a 33,000 mile car should. 150.00 almost new/old car.......... Good luck! I think Ryan and I had the same thought at the same time!

 

what kind of oil did you use to break it in?
I messed up a 460 last year because the oil wasnt break in oil.
It ran for 50 miles but the cam had already put metal in the oil.
One day the oil pressure droped and i caught it before it seized completly.
I was told it was from lack of zinc in the oil newer engines dont need zinc in the oil.

 

You build motors and know what you are doing. Sorry to here your story, Let us know, man!

 

He is long past that point. Starter out and checked. 3 foot breaker bar won't budge it.

 

Damn mate hope this turns out for you, hoping its something simple like Ryan's suggestion.

 

I'm getting ready to finally fire up my 8BA for the first time......damn, this gives me a sick feeling in my stomach. Let us know what you find.

 

Keep posting the autopsy as it happens! I hope it is something like a rod that can be changed out for another one weight matched.
I had one that I never did figure out...not hydraulic, not starter, siezed tight suddenly with only 280,000 kilometers onit. Replaced it with a crummy '52 I had, never took it apart and just occasionally put a breaker on the crank ratchet. A couple years later, I tried to heave it inot a corner and grabbed onto the flywheel...it spun easily and I nearly fell over from the try. Took it apart for rebuild many years later, not a thing wrong except normal high mileage wear. Aaaaaaah!

 

man, I feel bad for you, best of luck.

 

i had this happen to me twice in one summer. I learned though.

 

I'm only going to mention this since nobody else has. What was the recommended wall clearance for the pistons? The pistons may have siezed to the cylinder walls after you got the motor good and hot. Just something to take note of.

-Mike

 

man that sucks hope it is a easy fix

 

This was mentioned before but did you use ZDDP oil or zinc substitute? Non roller lifters will eat a cam fast if you dont have zinc in the oil.

Best of luck mate!

 

Any news ?? Pics ?? >>>>.

 

Wow that sucks!!!!!!

 

(The crowd of well-wishers continues to pace and fidget nervously in the waiting room. Occasionally, one turns pale at a sudden thought and rushes home to check ramp clearances on his flathead dweedle valve or to see if the bearing box really said ".030".)

 

I'm hoping Ryan's right about the starter.

 

I thiink Kevin is on to it. I run a flathead drag car and flathead Bville car with a buddy we used a high volume pump in one motor it only ran a short time and seized the crank bearings.We think it pumped all the oil out of the pan. We now run standard oil pumps with ni problems. Sorry for your situation. Gary

 

i'll third this theory.... thats a lot of pressure.

...and my experience with most flathead/ardun racers i have talked to and read about use stock pumps unless the oil capacity has been increased.

my injected flathead has a stock pump and pan as does my other built flathead.

whatever the problem may be, keep your chin up and keep at it.

 

You may want to visit the flywheel. I had a bolt break off the flywheel then blocked the starter.

 

Why did you burnish the bearings , don't know why anyone would do that !

 

Thanks everyone, just woke up and read all the replys quickly..every suggestion has been valid, but every one was also considered and checked before this engine fired up at all..early cranks have a very simple oil gallery system, no sludge traps etc.. so nothing wrong in there, used mono weight 30 running in oil, all piston clearances double checked..

the oil pressure is the one thing I cant make sense of..stock 39 oil punp should only create 40 PSI, im not convinced it really Does crate 80 PSI, but it is a little odd.
Ill drop the pan this afternoon, and let you know whats up when i do.

Thanks again for the concern and advice, I work alone so it really helps to have support from you all!