Lets move forward

My machinist said the block can be pinned (?) then re milled to fix block. I did a pressure test on the cylinders and found that all exhaust valves leaked. Removed them and can see why. Now for my question? The exhaust seat were replaced at one point (so that is at least 1 + to this block) I can get them ground when I get the block fixed and replace valves. does this seem like a good Idea or am I whitewashing a turd. I'll post in comments on how much I got s****ed or not when it all washes.

 

If they leak, and you want to use that block, then they have to be ground. I've never heard of grinding or replacing the valves without also grinding the seats. When they leak, both sides erode. If the seats will clean up, grind them and be happy!

 

Sure seems to me like you're expecting an awful lot from a motor that's 40+ years old. "Rebuild" means just that, you rebuild it. This means completely dismantling and reconditioning/replacing ALL parts and pieces.

All valves should be cleaned and inspected, and reground if they're usable, or replaced if they're not. Even brand-new valves should be ground to insure they're concentric, don't assume they're ready to use just because they're new.

All valve seats should be ground, period. Then the valves and seats should be lapped, period. All valve springs should at least be tested on a spring tester, or preferably replaced.

All cylinder bores must be checked with micrometers to determine wear, taper, etc., and the pistons have to be miked also to determine their fit to the bores. Ideally, you should just automatically buy the next size pistons w/rings, and have the cylinders bored to match.

Same with the main and rod bearings, cam bearings, cam, lifters, and so on.

In my opinion, an engine isn't rebuilt unless you rebuild it! Trying to get by on the cheap by only doing what you think is absolutely necessary is, in my opinion, when you're "whitewashing a turd". If you cut every corner you can and don't do everything right the first time, then you'll never have an engine that is completely reliable and trustworthy, that will give you 100%. Sure, you might save a few bucks, but it WILL bite you later.

If you don't want to spend the time and money to do it right, then why bother at all? Just put the motor in and let it leak, wheeze, smoke and fart until it dies. Do it right, and it'll outlive you. Do it half-assed, and you'll regret it.

I'm not trying to be harsh here, but this is the engine you're talking about, the most important part of the whole JEEP. Why take the chance that you'll have to work on it again later on. You've done some great work on her so far, why start cutting corners now?

Just my incredibly biased geezer opinions! I'm sure others will disagree.

 

Here's a link that may be useful.
http://www.locknstitch.com/Metal_Stitching.htm

 

First I'd let the machine shop triple check that block for other problems (more cracks, etc) before throwing more $$ at it. (a fool and his money are soon parted) If he will guarantee his repair ( I bet he won't) then do it. Then rebuild it as discussed above.
or
shelve this one, salvage what you can, and move on to another, IMO.

 

I suspect your machinist said the crack could be "Peened." Peening would cold work/harden the spot where the crack is running and stop the shearing action in the metal. It's a roll of the dice. If I were your machinist I wouldn't guarantee the item because it's dependent on variables in the crystalline structure of the cast iron of your block he can't change. I did it on my similarly cracked head and I've just got to wait till the rest of the restoration is done to see if it runs or comes up snake-eyes. Peening/drilling a small crack is a reasonable repair.

Your exhaust seats were probably replaced with stellite after the introduction of unleaded gasoline or your block may not be original and it was made that way.

Although I've heard stories of people who just rebuilt the head only or did a ring-job that lasted I suspect they were an exception not the rule. And like Rondog said, how reliable do you want it to be? I had a crack peened and used Clevite everything I could to rebuild my F-4-134.

 

Thanks guys I'll look at both blocks and decide which one to rebuild and do the thing right. I guess I just have to accept this project is going to cost alot of $$$$ and take more time to do it right. So it takes 8 years that still gives me 2 years of driving it before my son turns 16 and I have to give it up.

 

except for very early f heads they all came with hardened exhaust seat inserts . That crack can be repaired by pinning ( what is done is you drill and tap holes right in the crack and install theaded pins with a sealer ) this process has been used for years to repair blocks and heads .Bill

 

After thinking I agree Rondog is right (Harsh but right) I'm not rebuilding a pinto here and it is the heart of the thing. Thanks for the 56 B**** slap, if I want to be in your 56 club I have to do it right. Sometimes I need my father in the room.

 

1) Sorry about the tardy reply.
2) I'm not trying to start an argument. I'm trying to learn/understand.

SVE performance said he pinned cracks by drilling, tapping, installing threaded pins, and a sealant. I can envision the process, but don't understand why.

Drilling would stop the tearing of the metal. But why the threaded pins? Is it to produce a greater surface area for the sealant to adhere to? Wouldn't drilling/inserting an epoxy compound under pressure do the same thing with less effort?

 

Now Clay, I'm not trying to be harsh or be your father, I was just trying to get the point across that it should be done right, and not half-assed. I have to blame my dad, my oldest brother (the gearhead), and my high school Aircraft Mechanics teacher for my anal ways about engine rebuilding. I'd hate to hear you tell a story later on about how your motor sucked a valve on you and left you stranded out in the middle of nowhere.

 

We need a machenist to answer that. I wondered the same thing?

 

Never seen it done, or even heard of doing it, but it stands to reason that if you add up all the surface area of all the threads on those pins, you're greatly increasing the surface area of your repair. I personally would consider silver soldering the crack, or drilling/tapping/pinning and silver soldering those in. At least I'd research that option. Don't know if the metal in the crack could be cleaned enough for it to stick would be my biggest concern.

 

If you use the link in my last post, and then select "C-Series", there's an article about a brand of threaded pins.

 

Go to other classified section click on the e-bay lik for the 225 block IN BOSTON and buy it now for 125.00. Hows that work for yaR)
Steve OOPS sorry I thought you had a v-6

 

The process of closing or repairing a crack using threaded pins is called "block stitching" I have seen it used to repair obsolete big diesels (Cooper Besmears and Fairbanks OP's). They did it because there was no other choice. I would think it would be easer and more cost effective to find a donor block to rebuild than fixing yours. I just sold a running engine with a set of new tires on stock steel rims for $425.00. Look at that option. As far as the repair, it's done, and it lasts, how long none will guarantee.
Joe