confuscious say Shawn no work on cars anymore

[Shawns Fords]

I know many of you may have the answer to my situation. I sure am confused. LOL

Its not my Bronco but in my 81 F250. After driving it for a week or so I lost compression in #5 cylinder. started g like a steam engine. The decal on the back window should say "mosquito's fear this" I figure it was a busted oil ring. so I got a wild hair today to take the V/C off and see if maybe a spring busted and the valve just wasn't closing completely.

I found the exhaust valves pushrod had come loose and was taking a nap next to the #6 intake pushrod. I am just glad they didnt make babies, that would have been the end of homes for both of them.

My question is...Why in the world does the engine not have any compression when the valve is always closed?

[hockeydad4-22]

first of all let me say after reading the headline of this thread...... Phew... We need you, out at least I need you working on cars and old trucks for a good long while yet.

to answer your question... I don't friggin know, I can't even get an old bronco to start.

[ZOSO]

I say bent/broken valve or piston. Maybe a combo of both.

[Viperwolf1]

I say bent/broken valve or piston. Maybe a combo of both.

I'll second that.

[Shawns Fords]

Well I think I answered my own question with insight from some other friends. Plus some stuff I learned at school.

When the intake valve opens and the piston drops it brings air inside the cylinder. If the valve doesn't open it can not allow a large enough amount of air to compress. Bernoulli's principle perhaps? Maybe there is no volumetric efficiency?

I double checked my post and I said it was the exhaust valve, but it was the intake.

[Viperwolf1]

Well I think I answered my own question with insight from some other friends. Plus some stuff I learned at school.

When the intake valve opens and the piston drops it brings air inside the cylinder. If the valve doesn't open it can not allow a large enough amount of air to compress. Bernoulli's principle perhaps? Maybe there is no volumetric efficiency?

I double checked my post and I said it was the exhaust valve, but it was the intake.

That will cause it too. Make sure the pushrod is straight and put it back in. If you still have compression problems it's bad news.

[Shawns Fords]

Yeah Phil it is all back together, runs like a top. I don't know how many engines I have had thrown a pushrod. the last one was my FE 390 in my 69 Mustang. Threw three of em all of those bent like a noodle. The one I have now, it was just taking a nap next to the Exhaust on #6.


A friend has a set of lifters I can have to put in it that are new in box. These ones do not seem to be 100%

[ZOSO]

This a 460?

[Shawns Fords]

no a 400 my 4670 will go in as soon as I have everything needed for the swap, this engine will get reconditioned and go in my 78 which my Brother in law has now.