Buying a second block

Hey all,

Thinking about picking up a second block I found on CL. Really new to the engine rebuilding stuff, so I wanted to pass it by the experts. I would be looking to rebuild on this block while continuing to run my current block in the Tomato. Then, swap and sell my current block.

Here's the ad from CL:

Is $100 good for a head and a block? Anything specific I should be looking for or asking about? He's already assured me that there aren't any cracks in it and that the block is "20 over." I'm assuming that's the bore size?

 

Yep, 20 over means the pistons need to be 20 thousandths oversize. That's a common oversize dimension.

With receipts, that's a good deal. Realize that pistons are not cheap, ca $30-40 each, and unless your pistons are 20 over, you'll need new pistons.

A shop will need to install cam bearings for you - that's not something you can do.

Re selling your current block, used 258s don't go for much money, so you might want to hang on to your old engine or donate it to a friend's project. Also realize that broadly there are two eras for 258s, the early ('80 and earlier) and late ones. They interchange, but the early blocks are heavier and the early cranks have more counterweights. Personally I think the early crank is more desirable. This is likely a later block; there are more of them out there.

 

I'd agree with tim. Its sounds like a fair price, but its missing some expensive parts. As for early vs late blocks, the early ones are stronger, but unless you are building a real fire breather, even the late blocks should be plenty strong.

Here's something else to consider... Most of the value in this sale is the machined head. A head from the 4.2 is ok, but a 4.0 head is a great upgrade. IMO If you are gonna be building a motor more or less from scratch, why even bother with the 4.2 head? A 4.2 block with a nice RV cam and a 4.0 head could easily give you a 20-30hp boost over your current tired 4.2, and would be a great motor to have in the jeep.

 

Dang. Good thoughts. Perhaps there is more sense in just rebuilding the current block and putting that $100 towards that. It does sound like I'll be costing myself some significant extra cost for internals that I may be able to save if I just pull the current 258 and go through it.

A new head would be a good start to that... great idea.

 

Seller forwarded along photos of the block as it is currently stored in his garage. Has been there since it came back from the machine shop a couple of years ago:





Still largely undecided. Even if I don't go for a build on it right away, having another ready-to-rock block on the side isn't a bad deal. Could save me from having to look for a donor at some point when my current one runs out of juice... And, there has to be some saving passed along to me from not having to have my current block bored and machined.

Love these decisions. They're the best.

 

Looks like there is some rust that needs to be cleaned up, like rehoning the block.I take it he has the crank and rods. The nice thing about a second engine is being able to continue driving/enjoying your Jeep while you build the new engine. I've seen lots of people lose interest in projects while they are torn down.

 

Asked about the crank and rods and the approx date on the engine. Maybe he'll drop it down a bit and make it really worth my while... never hurts to ask, right?

 

What Kman says is true. Being able to keep driving your jeep, while re-building it, costs more in the long run, but if you can afford to, it is a pretty good way to go. Especially if it's a daily driver.

It's not for everyone, though. It's strictly a personal matter.

My jeep runs good, and is in pretty good shape, considering... but I want to do a frame off restoration. So, I bought another frame, set of axles, and another engine (401), new RE 2 1/2' suspension lift, and new shocks.

I have already restored the frame, and went through both axles. So, they're all set. Now, I can assemble a rolling chassis. When this is ready, it's time to start swapping.


Meanwhile, I'm still driving my jeep. I'll attempt to sell the original parts, later.

If I were you, and wanted to,I would buy another engine to rebuild, providing you can afford to. Some guys try to be thrifty with their jeeps, spending only what is necessary. And for whatever their reasons, that's fine. I can respect that. Life is expensive.

My jeep is my hobby. It's what I spend my money on. It's how I occupy my spare time.

That's why I say that it's a very personal decision. Man, I'm longwinded!

Rich

 

Rich and KMan - good counsel. And, that was where my brain was originally going.

We'll see what more information he can give me and then maybe I'll will just toss it into my father-in-laws garage for a year and see where it can go. If nothing else, I'll toss it back up on CL.

 

around here the older parts are hard to come by....scrap was way up and there they went to china or someplace 100 bucks id buy it just to have it but i love inventory......