Engine Rebuild Question

[jagiven]

We tore down the kid's 25 engine to rebuild the tranny. That's done, before putting it all back together, we decided we would check over the rest of the engine.

Right now it's a short block, only has the cam, pistons/crank, and valve train.

It is really difficult to turn over. I loosened the bolts holding the caps. I added a 1 ft cheater bar to the crank shaft, and it is still hard to turn.

Before pulling the crank shaft, how difficult should it be to turn over at this point?

[Henry K. Lee]

From the looks of it, it has been sitting for awhile? Might be more drag coming from the cylinders.

Hope this Helps,

Hank

[Ruxstel24]

I agree with Hank.
Take the rods loose and push the pistons up (if you can) and it'll probably turn easier then.
If the pistons are tight, I would take them out and clean/check cylinders and rings.

[Joe Bell]

Is bad as some one has cut the seat in two of the exhaust valve your chance of having a crack from the valve into the cylinder has increased.

[RajoRacer]

Agree on the exhaust seat - not good & you should really replace the original 2 pc. valves - this is what they like to do - "come from together " !

[jagiven]

So how can you tell they are two piece valves, from that image?

[RajoRacer]

By the 2 holes in the top for the Ford (& others) valve grinding tool.

[John kuehn]

The original 2 piece valves will usually have the 2 holes in the top of the valve that were used when grinding the valves with the older hand valve grinders.
In the pic of the broken valve shown the valve stem has the darkened end. The end is darker because it was up inside the back of the head of the valve.

[KeithG]

I absolutely agree with what the others said about replacing the 2 piece valves. Further, you should clean all the carbon from the top of the pistons & the block. By installing modern valves, cutting the seats and lapping the new valves in, you'll have a much better running and longer lasting engine.

Keith

[RustyFords]

Could just be the photo...but that #3 piston and cylinder wall look suspect.

[Kerry]

Don't assume just because of the 2 holes on top make them 2 piece valves, replacement one piece steel ones also had the tool holes right up into the 70/80's?. One would need to look at the other side of the valve head to know for sure.

[jagiven]

I'm guessing I have 4 two piece valves. They were in positions, 1, 2, 3 & 8.

[Kerry]

Jason, your guess is right.

[Jerry VanOoteghem]

Yup. Two piece valves. And, by the looks of most of them, they weren't really doing much anymore, except just going up & down. The engine photo also makes it appear as if the seats have been cut waaaaaay deep. Time for inserts I think, and new valves too of course.

[HaroldRJr]

I'm not too sure on this, but I think it might be possible to install oversize valves in that block without new seats. Seems like something like the slightly larger Fordson tractor valves or maybe a more modern automotive valve with modern valve spring keepers might be available. If that's possible, there is an advantage to carefully cutting new seats in the block for oversize valves,.....and that is that heat is radiated from exhaust valves directly into the iron block more efficiently than into a new valve seat inserts and THEN into the block. That of course means that the exhaust valves would run a bit cooler (and that's a good thing) than with newly inserted valve seats. Maybe somebody that know more about it than me might "chime in" here. Anyway, I'd sure check it out,....FWIW,....harold