250 Died today!

[tri-power 250]

I was going to do some timing work on the Mav today. I started it and let it idle to warm up. I rev'd it a little to have the engine start to stumble and hear a metallic sound. I shut it off then pulled the valve cover, restarted the engine and watched the rocker arms move. I notice the number 6 exhaust arm stop moving. Then the engine fluttered again and died. Either the lifter is dead or the lobe has worn flat. Just damn!
Time to start rebuilding a new short block.
Ken

 

[MPGmustang]

IIWIYS... take off the head, you can take a magnate and lift the lifter out. I would confirm what happened before doing anyhting else, Check to see if the engine has siezed or can still rotate. looking at what you have would make it go alot faster. maybe it's just the cam, replacing that would be easier than rebuilding a new long block...

Good luck and Keep us updated!!!

 

[69.5Mav]

Check to see if the engine has siezed

Good call. If the engine has siezed then more needs to be done.

take off the head

If the engine is not siezed up then.

First I would remove the rocker arm assembly and the number six exhast push rod.
Look down the push rod hole and watch the lifter body while you rotate the engine. Look to see if the lifter body is going up and down.
Also look to see if the lifter is the same as all the rest, some people here have found that the top of the lifter can come off of an old lifter though I have never heard of that happening to a running engine only when removing the push rod but I won't say it can't happen.

Also check the push rod for straightness and the rocker arm for non binding movement.

Good Luck and let us know your results.

 

[tri-power 250]

Today I pulled the head off to small washer in the #6 cylinder. It happened when I pulled the air cleaner stud out of the carb, forgot the washer was on top of the carburetor :roll: . The head, cylinder and piston looked alright. I did pull all 12 lifters and replaced them with new ones.
I tightened the head bolts,and the rocker assy down, pulled the plugs,with a remote starter I turned the engine over and watched the valve train move up and down. Everything looked fine. Tomorrow I plan to tighten everything up, change the oil and start it up let it warm up and adjust the rockers.
Oh yeah, the missing was a result of the spark plug getting crushed by the flying washer.
Thanks for your help,
Ken

 

[Frankenstang]

The head, cylinder and piston looked alright.

That would be cool if everything turns out just fine...fingers crossed for ya ...if not 'bullet proof' at minimum 'hurling metal object proof' 8)

 

[MPGmustang]

if not 'bullet proof' at minimum 'hurling metal object proof'

:rolflmao:

Oh yeah, the missing was a result of the spark plug getting crushed by the flying washer.

yikes
no scoring on bore or dmg on the valve it self? what about inside the valve bowl (only can see if you take out the valve...

Good luck!!!

 

[tri-power 250]

There wasn't any damage to the cylinder wall. The top of the piston wasn't marred up....too much, just little circles where the little washer layed, now the exhaust valve was a little beat up but not cracked. I was thinking of starting the engine and seeing if there were any problems.
I also noticed the #6 cylinder was running lean. Can you imagine?
The carb I'm running is a holley 300 cfm and the jets are 58's. At one time the engine seemed to have a vacuum leak every week. When power break canister was taken out, and the vacuum port on the manifold was plugged, my vacuum leak was fixed. I think that's when lean cylinder damage was done.
I have a set of new valves to put in a head. I am thinking of removing the head again and taking it over to a shop to get the valves replaced.
This engine will never be a racer, it just need to last me 1 more year, that will give me enough time to build my next six. This engine will have a fresh upper end by the end of the week.

Ken

 

[tri-power 250]

She' ALIVE! I had the new valves added and I added a set of lifters. Well, she runs great. Not a racer, but a really good daily driver. It's kind of funny, I let my girlfriend drive the car today, and I learned you CAN take off from a dead start in third gear.(4 speed car)!
Ken