Need advice on cracked block

[DBF 30]

I am a brand new guy to the Model A world. I have wanted one since I was 16 when my grandfather and I would go driving in my great uncle's all origional sedan that was stored at my grandfathers. So fast forward 38 years and I finally got around to getting one. I recently bought a 1930 Standard Model A roadster that is rough but is fairly complete, see my Avitar.

Probably paid too much for it but was offered a thousand more than I paid while hauling it home. My game plan is not to do a full restoration at this time. I just want to go through the mechanicals and get a solid driver where I can just enjoy driving it. Want it to be reliable but part of the charm will be the rust and dents.

Progress so far, engine starts and dosn't run too bad. However no cooling as in a leaky radiator and shot water pump. So only ran it for a short period.

After scraping about an inch of grease and mud off the engine block, I pulled the pan to check out the bottom end. I was pleasantly suprised at the condition. Pretty clean and tight, smooth turning crankshaft. Havn't pulled any bearing caps yet to check their status. I did notice that I have the split skirt pistons with the wire spring inside the piston going to each side of the piston skirt. I have never seen this set up before but I think I read that the split skirt pistons were origional equipment? If so this may be all origional.

Needless to say I was feeling pretty good about what I was seeing inside. I then looked up at the underside of the block and see about a 4 inch hairline crack in the water jacket between cylinders 3 and 4. Should have known it was going to good! If you look at the vin number on the block and follow the flat side down to where it curves under and then goes back toward the cylinders, that is where the crack is. Just as it curves under going back toward the cylinders. It is just big enough for a finger nail to ketch on.

So my question is how bad is this. I assume that I will now have to pull the engine, completly tear it apart, hot tank the block and then what?

I assume that getting this welded is a viable soultion or is JB Weld an option? What is the best long term fix and most economical way to handle this?

I was really hoping to avoid a total rebuild at this time. That looks like a pipe dream now.

Thanks in advance for your help.

[Kurt in NJ]

The wire spring is a piston expander, it was used to make a worn piston larger.

Glue the crack and run it ---stay away from trying to weld it ---good chance of doing more damage --it might not leak at all now, the "A" doesn't have pressure in the cooling system --even stop leak can work ---if you keep running it without coolant you can crack it at a valve seat-that is much harder to repair

[Mike V. Florida]

Clean it well, have it stitched.

http://www.jandm-machine.com/metalStitching.html

[Tom Wesenberg]

I would try Kurt's method first. Many have been fixed this way. In the very slim chance that doesn't work out, then you can go with the more expensive stitching.

[Aerocraft]

My suggestion would be to first search out and join a local Model A club. There are always a few guys in any club that have "been there" and are a marvelous source of help.

If you came to our club and asked me the same question, I would suggest that you have the crack metal stitched and would offer to do it for you. Unfortunately, it is easier to do the work in that location with the block out of the car. It would make a great Saturday morning "show and tell" tech session for all the club members.

Short of the metal stitching, a good block sealer and a glue "treatment" might serve you well. You may find that the crack doesn't leak as is. Run it and see.

Gar Williams

[BRENT in 10-uh-C]

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Funny as it may sound, I know of one instance where a hobbyist got MAD when he found out he had a cracked block that had been repaired with JB Weld simply by forcing it up into the cracked area. He bought this rebuilt Model A engine back in the 70's and drove it until it needed a rebuild. Therefore for 30+ years and 50,000+ miles the JB Weld has held just fine in that same area yet he "went off" on that engine rebuilder and chose to scrap that block because of the crack!

I have seen or know of quite a few that have been similarly repaired, and some that have just been brazed and they have performed reliably with no 'Runs, Drips, or Errors'. Just drill a small hole at each end of the crack. Stitching works well too. Therefore just let your pocketbook and conscience be your guide on which direction you want to go.

[Bob-A]

DBF 30,

JB weld if you can. Just like Brent said you would be amazed as to how many A's have been repaired this way and ran for years. I did it myself
on a '29 phaeton on the water jacket of the block right behind the oil filler
tube. Ran it for years with no problem. Good luck on your roadster and
remember: they are only original once! I'm doing the same on my '31 roadster. Just restoring/rebuilding what it needs mechanically to be safe
and reliable to drive.

AMF/Bob-A

[Dave in MN]

I would go with Tom Wesenberg and Brent's suggestion. Try the JB Weld first. I always use JB Weld first on the type of crack you describe. I Magnaflux the crack, mark its path with a permanent marker, drill a small hole (3/32") at both ends of the crack, use a Dremmel tool with a very thin cut-off blade to create a very shallow (1/32") deep channel exactly over the crack and then fill (actually mound it up over the channel) with slow set JB Weld. Optional step: The following process has worked exceptionally well for me. After about 2-5 hours of curing at room temperature, I lightly tap on the JB weld with a very small hammer to force the epoxy into the actual crack. Why the wide variance of time for the tapping...it depends on the setting of the epoxy. I start tapping as soon as the epoxy starts to set. I do not tap on it if it has stiffened significantly.
The extra surface area of the shallow channel allows the JB Weld to bond well to the repair area. After the JB Weld sets up over night, I remove the excess with a course file and finish it with sand paper. Removing the excess leaves only the epoxy in the shallow groove. The difference in surface texture can be masked by taking 80-180 grit sand paper, placing it over the repair and tapping it with a small hammer to create a surface to match the cast iron. After painting, the repair is not noticeable. I have been using this repair for the past 10 years and have not had one fail yet. I install "Lock Stitch" repairs in other areas of the block but often find the metal very thin in the area you describe making it a very precise and tedious process. Given the success of the JB Weld, I consider stitching an over-kill for this particular repair.
Good luck with your repair.
Dave in MN
www.durableperformance.net

[Kurt in NJ]

My advice was based on the piston expanders, stitching, or proper heating and brazing would probably mean total dissassembly ---then you will find that the bores are worn, then you will look closer at the babbitt and crank ---and the cam and valves ---unless you are ready to make the plunge into a total rebuild ---put it back together with a clean oil pan ans spend the money on the radiator and the brakes and enjoy the car for the summer.

[George Miller]

I would go with Kurt's and Tom. You do not plan on restoring the car right now. Why not try stop leak, what do you have to loose. If it is the original engine I would want to keep it with the car.
I have had Model A's with cracked blocks, it would bother me at all.

[Frank Miller]

"My advice was based on the piston expanders, stitching, or proper heating and brazing would probably mean total dissassembly"

The beauty of stitching is that it does not require that you disassemble the engine. If it is accessible the crack can be repaired right in the car. The suggestion of JB Weld seems most appropriate with all the testimonies that it does work.

[DBF 30]

Thanks everone for the advice. I have no problems with a crack repair using JB Weld. I will try this first. If that fails then I will look into stiching. I did some research on the sight and see that some are recomending the slow cure jb weld vs the quick cure, is that the way to go?

Also with the jb weld repair, do you still recomend drilling small 1/8 in holes at the ends of the cracks? or just beveling out the crack without the holes?

Due to the location of the crack I plan on pulling the engine for the crack repair and if the bearings are good to go, not do a rebuild at this time.

How about pulling the head? Origionally was just going to pass on it and drive it first to see how it performed. I normally wouldn't hesitate but have read of the problems with broken head studs that does not sound like fun.

Sorry for the thousand questions, but just don't want to make any more work for my self by digging into something that is ok for now. I have more than enough that has to be done to get this car on the road.

Thanks!

[Tom Wesenberg]

Don't pull the head unless there is some good reason to do so.

[Bob-A]

DBF 30,

You can never ask to many questions on this board. That's why we
are here: to ask questions, give answers and hopefully help each other
out. Whether we like it or not! Some of us can get kind'a silly
like me and a certian Ghost. But what the heck, we are all friends and A-Model lovers, right?

AMF/Bob-A

[Robert]

Clean it well and J-B Weld it.

[hardtimes]

DBF,
Yes..drill the 18" holes ...one at each end of a crack! The idea of these holes is to STOP the crack from expanding/spreading. Good luck.

[callcoy]

I believe in the JB Weld type material for your application, so does the Automobile and Aircraft industries, among others. The first thing you have to understand is that your cooling system is not pressurized, the water is almost just sitting in the water jackets being pushed around by the water pump. I don't know if one could even find a way to measure if there is any force as the system is more or less open but contained by a lid.

I have a "B" block with the same crack you have discribed, commonly called a freeze crack. I prepared the crack like the others suggested, used the slow set JB Weld. However I didn't do the hammer tapping described. I let it cure for several days then bolted on the pressure testing plates and to experiment, started at 20# with no leaks, when for broke and took it up to 40#. I found no leaks even after trying to get it to fail.

I don't think that a lot of individuals realize that epoxies play a large role in our lives, we wouldn't have many aircraft flying without them. For years all major aircraft mfgs have been bonding planes together, the Air Bus 380 and Boeing Dreamliner are just recent examples. There may not be a car produced today that isn't assembled with the same type of material we are talking about here.

A side note not really related but may be of interest to Model Ar's is an unusual application of JB Weld at Bonneville last year. A fellow I know used it on a aftermarket flathead that is on his Model A powered Lakester. Not only did it hold, but he went 5 mph faster and set a new worlds record.

Oh by the way, if your repair was my block I would add a block sealer after the JB repair, the pour in type just to play it safe. On mine because it was disassembled, I used Irontite heated under pressure for 24 hours.

[DBF 30]

Thanks to everyone for the replies and all the great advice. I will use JB Weld to fix the crack. If the bearings check out ok, I will try to do the repair with the engine still in the car. Should be interesting trying to prep and glue upside down but I'm sure that not a lot of material will be required to get a good seal. Besides nobody will be able to see it at that location anyway. I will post again and let you know how it turns out.

Thanks again for the help.