To rebuild or not to rebuild this old engine?

[Willl]

If it were mine....

Clean everything sparkling clean.
Hone and re-ring, set of rod bearings, hand lap valves and reassemble w/ new gaskets.

 

[TYMinColton]

If it were mine....

Clean everything sparkling clean.
Hone and re-ring, set of rod bearings, hand lap valves and reassemble w/ new gaskets.

Took the words right out of my mouth. Thanks everyone. I'll let you know how things turn out in a few weeks.
Regards,
Pete

PS Do you wish it were yours?

 

[RobJ]

Daryl beat me to it.. but yeah.. hand lapping.. usually gets the seat and valve fairly decent.. and is great for your forearms!

soundguy

But hard on the hands!! If they are soft that is.

I've been using a drill for some time now. Attach to the stem, forward, reverse, forward, reverse, pick up move, etc. Takes a while if they are that bad. When I was doing this for a living we had the stones. Did the 3 way grinding on the street engines after hours. On the diesels, just the regular touch up. The clover mainly just told you if you did a good job and the seat was square in the middle.

 

[john_bud]

Couple points....


The valve guides on a ford 172 are press fit and cheap. About 4 bucks each. If you have a press, it's a pretty quick job to swap in some.

I too, would just hone and use oversize rings hand filed to the correct fit. Add bearings and it will be good to go for a long time.

 

[TYMinColton]

But hard on the hands!! If they are soft that is.

Soundguy,
Are you saying that I have soft hands? What gave you that impression?

Stupid bearing related question: How do I know what size rod bearings to purchase? The I&T manual indicates they come in several "undersizes" ranging from 0.001-0.002 to 0.02, 0.03, etc. Do I just measure the existing bearings or is there a standard set that goes along with my 0.02" oversize pistons? And yes, eventually I will get around to picking up a ford shop manual - just having some trouble with CTP and e-mail . . . . .
- Pete

 

[TYMinColton]

The valve guides on a ford 172 are press fit and cheap. About 4 bucks each. If you have a press, it's a pretty quick job to swap in some.

John-bud, you might very well be correct on this one. The I&T manual I've been using is a little unclear. According to Paragraph 90, "Intake and exhaust valve guides are interchangeable only on non-diesel models and can be pressed from cylinder head if renewal is required."

On the other hand, the valve seats may be a different story. Paragraph 89 states, "Exhaust valves are equipped with free type rotators shown in Fig. F071 and, except on 144 cu in diesel engines, the valves seat on renewable type seat inserts which are shrink fit in the cylinder head. Intake valves and, on 144 cu in diesel engines, the exhaust valves seat directly on the cylinder head."

If I understand these paragraphs correct, both the exhaust and intake valves seat directly on the head for the 144 cu in diesel, but on the 172 cu in, the exhaust valves (but still not the intake) sit on renewable seats. Moreover, valves guides appear not to be interchangeable on any of the diesels engines. Seems to me that it would then be very difficult to remove the exhaust seats from the bottom of the head, while leaving intact the valve guides on the top of the head. Perhaps I haven't looked carefully enough, but I wasn't able to see any obvious seams for the valve guides. However, the seats do seem renewable . Adding to the confusion Restoration Supply company does indeed sell intake and exhaust valve guides $3-4 each . . . .

Does anyone understand this? Maybe someone out there with the ford shop manual can help me (us) out?
Pete

 

[Soundguy]

Soundguy,
Are you saying that I have soft hands? What gave you that impression?

Stupid bearing related question: How do I know what size rod bearings to purchase? The I&T manual indicates they come in several "undersizes" ranging from 0.001-0.002 to 0.02, 0.03, etc. Do I just measure the existing bearings or is there a standard set that goes along with my 0.02" oversize pistons? And yes, eventually I will get around to picking up a ford shop manual - just having some trouble with CTP and e-mail . . . . .
- Pete

I believe it was RobJ that may have been implying you had soft hands..

As for the bearings.. they won't specifically be matched to the pistons.. but to the journals.. cam / crank..e tc.

They may be stamped on the back of the shells.. or you can plastigauge / mic the journals.. etc.

soundguy

 

[TYMinColton]

I believe it was RobJ that may have been implying you had soft hands..

As for the bearings.. they won't specifically be matched to the pistons.. but to the journals.. cam / crank..e tc.

They may be stamped on the back of the shells.. or you can plastigauge / mic the journals.. etc.

soundguy

Thanks I'll check out the shells more carefully. And I should probably come clean about the hands thing - - - yup, baby soft .

 

[firefighter9208]

When lapping the valves by hand paint the valve seat and bottom of the valve with a permanent majic marker (Red works well). Then when you are lapping periodically check to see if the marker is worn away. When you have an even wear on the valve and the seat your good to go. You'll see what I mean.

Also, when filing the rings you need to make sure you place them squarely in the cylinder. That means to place the piston in the cylinder and then slide the ring down on top of it. Take a feeler guage and check the end gap. Remove the ring from the cylinder and file. Replace in the cylinder and check again. Repeat this process until you get the end gaps correct.

Warning: You will have to file each individual ring to fit the individual cylinders. If you don't do this correctly you will weld the ring to the cylinders upon start up.

BTW you can buy a ring file from Jeg's High Performance. JEGS Piston Ring Filer - JEGS Rings are fairly hard material and the gap is small, so it's not hard the break them when trying to file them with a hand file.

Chris

 

[TYMinColton]

BTW you can buy a ring file from Jeg's High Performance. JEGS Piston Ring Filer - JEGS Rings are fairly hard material and the gap is small, so it's not hard the break them when trying to file them with a hand file.
Chris

Ouchy - not cheap! Like so many things in life, I'll probably just start by taking the low (cheap) road, and then realize after busting a ring that it would have been better (and cheaper) to just spend $50 up-front on the right piece of equip. I guess if I were a mechanic these "small" expenses (hones, bore gages, etc) would be no brainers, but as a hobbyist , just can't swing it.

Thanks for the advice however, all these little suggestions are really helping with the visualization process. Now if I could only figure out how to have all of you present for the final operation .