Hairline Crack

[JSeery]

Originally Posted by tubman

Back in the '60's I re-ringed a block with 7 such cracks. It was running fine when I sold it a couple of years later. I will admit that I must have been lucky and also that I purchased a lot of "Barr's Leak" over that time. ("Re-ringed"sounds bad, but "re-rung" sounds worse.)

How did the valves seal on a cracked seat?

[Jack E/NJ]

Probably not well in a leak down or compression test. But probably hardly noticeable while running either. Jack E/NJ

[tubman]

Let's face it; I had no idea what a flathead in top shape should run like back then. Jack is correct though; it got me back and forth to school just fine for a couple of years.

[Eagle43]

Originally Posted by JSeery

That is not an option that will work! The cylinder would require a sleeve and the valve seat would require an insert if you are not interested in stitching the crack. You would also need to drill the ends of the crack to stop it from spreading.

Yes, in an ideal world you are correct especially if I was working in a machine shop and the work had to be guaranteed. However, I'm working at home with rudimentary tools. I spent my working life as a classroom teacher. I'm retired and doing this for fun and as a learning experience. At my age I don't expect to be able to drive it for that many years. I guess I'm wondering if there any other options other than throwing out the block and starting over with another block which I really don't want to do even though I know of several that are available to me.

Counting on putting in this flathead, last week I also acquired a set of front corner motor mount plates and a replacement transmission mount cross member. I spent two afternoons at the local scrap yard cutting off numerous frame rivets with a cold chisel and a big hammer to get these. Luckily the donor truck's floor was completely rotted out and the motor was missing so the cross member and corner plates were easy to get to.

I could also go back to Plan A and modify and reinstall the FE 352 that is presently in the truck. As it's now installed is a real butcher/hack job that would never pass the safety inspection I would need in order to license the truck. Whoever did this work really loved his cutting torch.

Regarding drilling the crack ends, this will also be hard to do. The bore crack is well into the active part of the bore and I don't want to mess that up. The other end is under the valve seat and probably impossible to get at.

I thought I could fix the problem with stitching but that doesn't seem to be an option according to LNS. They don't seem to want to sell me a kit either. Are there other companies that sell stitching supplies and could advise me? Does anyone know how to put in new valve seats?

[Bob/Ohio]

Eagle43,
Check with Irontite. You can talk to them and see what they say. Different type of plug than Lock & Stitch. They are cheaper and you don't have to buy a kit.


Bob

[woodiewagon46]

Sponsored Links (Register now to hide all advertisements)

I think Jssey is correct. If you look very closely you can see a slight displacement on ether side of the crack. IF you can get it repaired a new sleeve and valve seat is a must.

[Eagle43]

I checked carefully again and I found another crack. I showed pictures of the cracks and spoke to a guy with lots of experience with old blocks at a local machine shop and he said that they wouldn't touch it. He said that his experience tells him that sleeves aren't a good option since the water can still get past the sleeve. He said pinning would probably work but not a practical option for them in this case since their shop rate was $120 per hour. Its a labor intensive job and the outcome is uncertain. I also contacted Irontite and the representative said he thought pinning with their A-235 plugs should work for this situation.

I've decided to go ahead and order Irontite plugs and a taper tap and give it a go. My cost will be $181 CAD including shipping for a box of 100 A-235 plugs and a tap and drill bit and it should be an interesting project. Since I'm retired, time is not an issue. At worst I'll screw it up and I'll be looking for another block. In any case it will be a great learning experience.

[Bob/Ohio]

Eagle43,
There is a video on YouTube of a shop pinning a Model A block. You might want to check it out. Good luck.


Bob

[Russ/40]

Eagle43, please take a photo series and share with the rest of us. Id love to be there to watch. Id like to try it sometime.

[Eagle43]

Originally Posted by Russ/40

Eagle43, please take a photo series and share with the rest of us. Id love to be there to watch. Id like to try it sometime.

I will. I just ordered a box of 100 Irontite A-235 plugs, a tapered tap and a drill bit from Ebay. Cost me $183 CAD including shipping and it should arrive in about two weeks.

[Bored&Stroked]

You might be able to pin it - has been done thousands of times in exactly this area. BUT - as some mentioned, you need to bore the cylinder and install a sleeve in it and you need to have the valve seat machined for a new hard seat and have a hard seat installed. This is done AFTER you pin the block (both operations). If you're going to spend time on it - might as well get it right. THEN - after both operations (and the pinning), you should pressure test the block - before you go to the expense of a valve job and all that jazz.

[Fortunateson]

As a retired classroom teacher myself I'm eagerly waiting on pics!

[rotorwrench]

There is a good chance that the exhaust valve pockets still had hardened stellite seats in 1951. FoMoCo phased them out completely in cars but the trucks still had them. If there is no removable seat then it will have to be counter bored for a hardened seat anyway after the pinning process is completed. Some folks have gotten by without a cylinder sleeve but most machine shops would recommend one just to insure sealing. Some JB-Weld can be used around the sleeve ends if a person is worried they might leak. I've heard of folks doing that successfully after boring through the cylinder walls to install larger bore sleeves. There is always risk involved. There is risk involved with purchasing any flathead engine now days.

Hopefully Tod B. can come up with some new block castings one of these days.

[Tim Ayers]

Originally Posted by rotorwrench

There is a good chance that the exhaust valve pockets still had hardened stellite seats in 1951. FoMoCo phased them out completely in cars but the trucks still had them. If there is no removable seat then it will have to be counter bored for a hardened seat anyway after the pinning process is completed. Some folks have gotten by without a cylinder sleeve but most machine shops would recommend one just to insure sealing. Some JB-Weld can be used around the sleeve ends if a person is worried they might leak. I've heard of folks doing that successfully after boring through the cylinder walls to install larger bore sleeves. There is always risk involved. There is risk involved with purchasing any flathead engine now days.

Hopefully Tod B. can come up with some new block castings one of these days.

Yep. When I was younger, I never believed all the jazz about flathead blocks being cracked. Maybe because my first three I purchased were good. I guess beginners luck for I've recently torn down two 99A's and both were cracked liked yours.

The first one (worst crack of the two) came out a running car that never ran hot. Plus, two of the crank throws were so badly worn, you can actually see that the throws are egg shaped. One of the bearings was in two pieces. Motor still ran well.

[Eagle43]

Well, the Irontite plugs and tap came on Tuesday and I finished the job Friday. It was an educational experience but I think I'm OK and ready to reassemble the engine tomorrow after I pick up a couple of hardened seats. The first one went very smoothly and I was filled with optimism. Then I got to the second one and nicked the hardened seat and broke my tap. However all was not lost. The broken pieces came out easily and so did the valve seat. I ground the end straight on the tap and carried on using a bigger drill bit. Since the plugs were tapered I also had to cut off a piece off the end of each plug so they would fit. However there was an advantage in that I could reuse some of the ends of the used plugs. When I thought I was done, I pressure tested the block by making a plywood cover and blowing in air with my shop vac. Spraying on soapy water revealed that the first cylinder was good except it was still cracked in the valve guide bore which can't be reached but should be ok if I glue the guide in with JB weld. The second one had leaks and I had to redo some plugs. I made a hone out of plywood disks and some threaded rod to finish the inside of the cylinder bore.

[tubman]

Good Luck. Be sure you let us know how it turns out in the end.

[Eagle43]

Here are the promised pictures: 1. The 100 A-32 Irontite plugs, tap and drill bit I bought. 2. An example of a plug screwed in. You basically drill, tap and screw in the plugs, cut them off a bit proud and peen them. You overlap them and angle them at different angles. I put some sealer on the plugs before screwing them in. 3. Finished cylinder #3 which looks great and went flawlessly, I think. 4. I protected the inside of the cylinders with some shim stock to prevent scratching them while cutting off the plugs. 5. Pressure testing with a plywood cover and shop vac. 6. My shop made hone to true up the cylinder walls. 7. Finished cylinder #2 - not as good but serviceable I hope. There was some distortion along the crack. 8. One of the finished valves and deck. It's hard to drill holes at these angles. With a hardened seat hammered in the repair should be almost invisible.
Some lessons I've learned:
1. Check for cracks before you start working on the engine. A simple pressure test with soapy water should show up the cracks connected to the water jacket. I suspect most of us don't have magnaflux equipment at home.
2. Buy two taps even though they are expensive. They are really easy to break. Make sure you line up the tap with the hole. There shouldn't be much resistance as you turn in the tap. Stop and realign if you get resistance - don't force it.
3. Take your time - it's easy to screw up. However most mistakes can be fixed with more plugs.
4. A die grinder with stones works well. Be very careful if you use an angle grinder. Better yet - don't.
5. If you have replaceable hardened seats, pry them out before you get anywhere near them.

This type of job is about as difficult as it get with cast metal repair. I have a couple of 1928 Chevy heads that have cracks. They should be really easy compared to this. I still have lots of extra plugs to use up.

[tubman]

Thanks for posting this. It looks like something a mere human could do.

[Admiral]

Well done and thanks for sharing photos! I've got an 8BA block in the garage with a similar crack between the valves. This thread gives me the confidence to try and salvage it.

[Russ/40]

Eagle43 hey, thanks for coming through with the photos of your process. You did good and instill some amount of courage in the rest of us considering doing the same. Thanks