Whimpy F Head

All good questions guys,
So far I have checked
points gap (dwell), good
plugs and gap, light tan color, good
timing, and revved the engine to see if the advance worked, and it did, good
compression, not good. I did not do a compression test anytime soon after the rebuild, wish I had, bad
I had not checked the dist. shaft to see if it would spring back, but I have now. it does not. I just oiled it a tad, bad
The hills I am talking about are between here and work. Its never been fast, but it used to do better than this.
I am thinking worn compression rings, but I would like to exhaust other possibilities before I pull the engine.
Thanks a bunch fellers

 

This is what is pointing me toward rings and not much else.

 

Mice in the muffler? Don't laugh, it's happened to me.

A vacuum test is quick and cheap, and very informative.

 

I forgot to say, I checked the vacuum also, about 17-18 in. IIRC

 

tell you what, advance your initial timing a bit. Like up to 10btdc and see how it runs.
What altitude are you running at?

 

If you lay your CJ over on it's side, you just about do a full rebuild on it.

 

I'll try advancing the timing, worth a shot. I'm only about 2500 ft. elev.
Anyone know where to buy rings that are not Omix?

 

I bought a set of rings from Rockauto about 6 months ago for an F head, they were Sealed Power for $45. Said they were made in USA. The motor is about to go into the 56 I just bought. Hasn't been run yet though.

 

The ones I see listed for a 134 are for a L head. Are they the same?

 

Yes, I did test fit. I forgot now what the ring gap measurement was though. seemed good at the time

 

Yes, rings and pistons are the same.

I put the same rings in my F-head. I got 100-105 psi on a compression test at about 2000 miles. A little low, but I'm using a HF gauge. I need to take it to work and check the calibration. Besides, it runs just fine down the road, but sucked on some of the hills I drove in TN.

 

May sound goofy, but could the gaps in the rings have all lined up? Although I would think you would get signs of oil-burning, then.

 

It is possible that you just need to drive it more. The compression readings will come up with constant use. And maybe quit expecting it to act like either your v6 or v8 Jeeps on the hills. Running up hills in second gear is just something we F-head and L-head owners live with. I have had quite a few vehicles over the long years back to the late '60's when I got my first license that would not go up some grades without dropping back to second gear. VW bugs and buses come to mind. '49 and '50 Chevies with flat-head 6 cylinders also. A lot of the v-8's up through the late '70's would not go up a lot of grades in the Rockies at more than 45mph in second gear. Just a fact of life, know what I mean?

 

I'm afraid this is real, to a certain extent. I've always enjoyed power, not speed, just power. The Dauntless in the blue cj 6 runs great, and with OD I can keep up with traffic on the local roads.
The 360 in the camo cj5 is tired and smokey, but will easily do its share of pulling.
I've decided to go ahead and put rings in it and hope it fixes it. I guess an F head is an F head, but a wimpy F head must have help.

 

I don't know, I think a healthy F-head can feel downright spunky. With a stock jeep on sensible tires, a good-running 134 is still enough to make you grin.

 

Try putting the windshield down.
Wind noise will help create that effect. (Along with transmission whine, tire hum, and fan howl…! )