f-head rebuild possibly

I am looking to get a full rebuild kit for an f-head for christmas from the parents. comes from kaiserwillys.com and you get all the nessesary parts, new oil pump and all the gaskets. I also have the chance to pick up an engine stand in the next couple of weeks. I've never done this before. arw there any special tools that i will need to look at buying/renting/borrowing. probably for the piston rings right?

 

First you need to have the machine work addressed before ordering the kit. If the cylinders or crankshaft need machining you will need to order the kit with oversize pistons, rings and or crankshaft bearings. With that said you will need a good torque wrench, piston ring compressor and a valve spring compressor. also I wold highly recommend a good service manual. I recently rebuilt my L4 134 with good results, had some fun and saved some money. GOOD LUCK !

 

I just noticed you have a F head, You won't need a valve spring compressor if you have the heads done at the machine shop, they will reassemble the head as part of the valve job.

 

I havent started dissasembling the motor yet so i dont know what the condition of the cylinders or crankshaft are. Besides maybe some surface rust the cylinders shouldnt be too bad, and thats something a wire brush could take care of right? What would need to be machined on the crankshaft..(worst case)?

 

One more time, You will need a valve spring compressor, the F head has valves in the block as well as the head, Sorry for the confusion.

 

The cylinders wear, even if you dont have obvious rust or scratches if they are worn out of tolerance you are wasting your time and money to put new rings in, you won"t restore the compression. Same with the main and rod journals. If they are worn you won't have good oil pressure and the rebuild won't last. If done right the engine will last years.

 

Just a couple of comments...

With a steel crank (like L134 and F134) you probably won't need to have the crank ground and use undersized bearings. You MUST measure though; the shop can measure for you (though they have a conflict) or you can buy/borrow a micrometer and do it yourself. I'd also recommend using plastigage at assembly time, just to double-check.

The cylinders will wear tapered (largest at the top). You can put your old pistons and new rings in tapered bores, but the rings will flex a lot as the pistons move up and down and fatigue prematurely. This is important because new oversize pistons are expensive, and you don't want to overbore if it's not needed. It's a tradeoff, depending on how much taper there is, how long you want the rings to last, and how much money you have to spend.

 

One more thing to consider before ordering the kit, even if you don't plan on doing machine work the engine is 50+ years old and may have been machined in the past. Your pistons or crank may have been machined already. You need to either be competent at reading a micrometer or have it done. Personally I thought it was worth the cost of having the block hot tanked and accessed by a machinist. A good local machinist will only do the work needed.

 

i know someone who may have a micrometer. I dont have a dingleberry hone if i needed it thou. I guess i need to get an engine diagram which has all of the correct tolerances and torque specs also.

 

i'm begining to get worried about the whole process. maybe sending the engine to a professional rebuilder would be the best option. Right now the engine seems to run fine, however since last summer it hadn't been run for 20 years. I would like to get the best proformance and life out of it as i can, but if im not having trouble right now...is it worth the money? I would like to replace some of the gaskets on stuff though, maybe i should just worry about the stuff that i can easily get at. The jeep is not going to be used for hardcore off-roading, just some trails and some easy rock crawling here and there. I have to buy a new body, wiring harness and top still. I just dont know how much im getting myself into.

 

I can understand your concern. Just because the engine is old doesn't mean it needs to be rebuilt.

You should look first at oil pressure and compression. Loss of compression and low oil pressure are the two leading indicators of engine wear. If these are ok, I'd leave the internal parts of the engine alone.

 

ok, whats the easiest way to test for compression and oil pressure?

 

You should already have a guage for the oil pressure. If it doesn't work, you need to fix it. The hot idle and hot running pressures are relevant.

You need to buy a compression tester. I bought mine at Pep Boys for about $25. Comes with instructions.

 

My point was simply don't order your rebuild kit before you know what you need. In my case the pistons were standard and the crank had been machined. Had I ordered a kit before disassembly even if I didn't do additional work I wold have had to return the kit and order the correct kit. If you have good oil pressure and good compression all you will gain is some experience. On the other hand if you want to do the rebuild go for it. Armed with a good service manual and possibly a little help you can do it. If you have a decent shop it can be a great winter project. If you run into a snag there is lots of experience right here. Heck if I can do it anyone can.