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Supersonic rebuild

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Agas46cj View Drop Down
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    Posted: 02 Aug. 2022 at 8:26pm
I’ve got low compression in my 47 2a. 80,85,80,75. After much searching it seems the likely culprit of running like crap is blow by on the rings. I’ve eliminated everything else I can think of or search for. I have a supersonic engine in it, block and head, and am going to have to at the very least replace rings and whatever else goes with that, or more likely a total rebuild with bigger pistons etc. I won’t fully know until I get it apart. My question is can I use the gear driven rebuild kit for a 134L on Kaiser Willys or because I have this motor I wish I didn’t do I have to find things specific to it?
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Bruce W View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 02 Aug. 2022 at 8:53pm
  Everything inside the engine is the same. The only differences between the Go-Devil and the SuperSonic is the head, the intake manifold, the carburetor, and the distributor. 
  Did you do a wet compression test? Don’t start taking things apart until you have run all the tests necessary to decide what the engine probably needs. Then you can start taking things apart and measuring parts to determine what it needs. Maybe an overhaul will fix you up. Maybe you dont need a rebuild. 
BW 
It is NOT a Jeep Willys! It is a Willys jeep.

Happy Trails! Good-bye, Good Luck, and May the Good Lord Take a Likin' to You!

We Have Miles to Jeep, Before We Sleep.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jeff J Quote  Post ReplyReply Direct Link To This Post Posted: 02 Aug. 2022 at 9:03pm
Originally posted by Bruce W Bruce W wrote:

 
  Did you do a wet compression test? 

I have never heard this term before. I frequently do differential compression tests at work and only occasionally do what most people consider a compression test. Maybe 5 or more years since I had that gauge out. There can be a big difference between a hot and cold compression test. Please elaborate on the “wet compression test”. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 02 Aug. 2022 at 9:04pm
It is a gear driven L134. There are only a few very minor differences between the engine used in the cars, and those used in the Jeeps, but don't start buying any "rebuild kit" until you take it to the machine shop.

You have evidently done a compression test. Did you also do a leak down test to determine whether you are loosing compression by the rings or by the valves ? Blow by can usually be determined by it puffing out of the oil fill tube where you can feel pressure with your hand over the tube. 

If you do proceed with a rebuild, the first thing is to take the block, head, crankshaft, rods and pistons, to a good machine shop for cleaning, and inspection. They can tell you whether it needs to be bored oversized, and how much the crank needs to be turned. Need to know all that before ordering any "kit".

Come back on this forum when you know what you need, and we will steer you toward a supplier with quality parts. Many sell the imported Omix-ADA stuff and don't tell you that, some suppliers sell better quality stuff.

  
Be prepared for sticker shock. It is no longer cheap to rebuild one of these things. 
If you can't get there in a Jeep you don't need to be there!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 02 Aug. 2022 at 9:09pm
A "wet compression test" is what I called a leak down test. The first series of compression tests are done as is and compression of each cylinder recorded. Then a small amount of oil is injected into the cylinders, and a second series of compression tests are run. If there is 10 percent or more difference between the two series of test this indicates compression loss around the rings which are better sealed due to the oil in the second series. If there is no difference, or only a small difference, the compression loss is due to the valves not sealing.
If you can't get there in a Jeep you don't need to be there!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Agas46cj Quote  Post ReplyReply Direct Link To This Post Posted: 02 Aug. 2022 at 9:20pm
I did not do a wet test, I will do that to see what the results are, I do however have plenty of puffing out the oil tube. I didn’t plan on buying a kit until I got it to a shop, I figured it would be pointless until I knew what size pistons I would need. Machining is expensive yes. I fix cnc mills and lasers for a living. Not happy about having to pay to rebuild an engine for a cj l just bought.  I did buy it as a project and I definitely got one. I searched for info on the supersonic. Found all sorts of things and contradictions on what had to and not be changed to put it into a cj. I bought the cj with it already in, so anything that may have needed swapped has been already. The issue is what was swapped and what do I need to buy when I tear down and rebuild this thing. Anyone want to trade a similar condition motor for a supersonic? 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jeff J Quote  Post ReplyReply Direct Link To This Post Posted: 02 Aug. 2022 at 9:22pm
Makes sense. When I do the leak down tests I am usually close enough to the tail pipe I can hear the air escaping through the exhaust valves and, as stated, air past the rings can be felt or heard at the blow-by. The vast majority of my compression checks are done on engines with horizontal pistons so a couple of drops of oil wouldn’t do me much good most of the time but this is something for me to file away for use on the jeeps and tractors. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 03 Aug. 2022 at 1:07am
  A wet compression test is as Oldpappy described. It can help you decided whether the leakage is at the rings or the valves. A leak-down test is entirely different. Compressed air is put into each cylinder with a device that allows you to measure the percentage of leakage from that cylinder. Listening at the oil fill tube, the carburetor, and at the tailpipe can indicate where the air is leaking. 
BW 
It is NOT a Jeep Willys! It is a Willys jeep.

Happy Trails! Good-bye, Good Luck, and May the Good Lord Take a Likin' to You!

We Have Miles to Jeep, Before We Sleep.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Agas46cj Quote  Post ReplyReply Direct Link To This Post Posted: 04 Aug. 2022 at 7:19am
Just did my wet compression with a little 30wt in the cylinders. I got 115, 120, 115, 115. Looks like bad rings? It also ran a whole lot better with the oil it in until it burned out. I think the jeep gods knew it, it ran out of gas in the garage. 

Edited by Agas46cj - 04 Aug. 2022 at 8:33am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Agas46cj Quote  Post ReplyReply Direct Link To This Post Posted: 04 Aug. 2022 at 10:38am
After reading my service manual I think I’m going to attempt to replace the rings without removing the engine. Should I replace the head studs while I have it loose and are the rings from Kaiser Willys ok to purchase one I verify piston size. Also is there anything else recommended I do while I have the head and oil pan off? 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldtime Quote  Post ReplyReply Direct Link To This Post Posted: 04 Aug. 2022 at 10:49am
Buy Hastings rings.
It’s true, the best rings, filters and casites that money can buy.


Edited by oldtime - 04 Aug. 2022 at 10:59am
Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963)
Zero aftermarket parts

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 04 Aug. 2022 at 11:39am
  Once you get the head and oil pan off, and the pistons and rods out, you can measure the bores for taper and examine them for scoring or other damage. You can also examine the pistons for wear on the skirts and the ring grooves. Then you can determine whether your engine is a good candidate for an overhaul. Note I didn’t say rebuild. If your bores, pistons and crankshaft are in good enough condition for an overhaul, then you can order your parts. You probably should replace the rod bearings and consider a valve grind at this time. The head studs can be evaluated once you have them all out. If they’re not rusted up and you don’t damage them in removing them, you can probably re-use them. 
Good Luck!
BW 


Edited by Bruce W - 04 Aug. 2022 at 11:44am
It is NOT a Jeep Willys! It is a Willys jeep.

Happy Trails! Good-bye, Good Luck, and May the Good Lord Take a Likin' to You!

We Have Miles to Jeep, Before We Sleep.
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Agas46cj View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Agas46cj Quote  Post ReplyReply Direct Link To This Post Posted: 04 Aug. 2022 at 5:04pm
For tools I have to do the job I have cylinder ridge reamer, ring compressor, feeler gauges, valve spring compressor, bore micrometer, valve lapping tools, torque  wrench.  Is there anything else specific to the job at hand that I would need in advance? 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cpt logger Quote  Post ReplyReply Direct Link To This Post Posted: 04 Aug. 2022 at 10:44pm
I am going to jump in here to ask a few questions & perhaps suggest a different route.

As I understand it you just got this engine & have no idea as to it's history, is that correct?
Thus, you do not know when it was last driven down the road & how well it worked? Is it probable that the engine has sat for a while, perhaps a year or two? What is your intended use for this rig? Will it be a DD, a trail rig, a parade queen, a show Jeep, or some combination of the above?

Do you have access to a bore scope to look into the cylinders? I am a bit unsure as to whether one can snake one of these down into the cylinder on these flat head engines. Some FLAPS, +/or machine shops will rent these bore scopes out.

Have you done a "leak down test" often called a differential compression test? This is the one where you introduce compressed air into the cylinder at TDC at a specific PSI, usually 80 PSI. A reading is taken & one listens to the tail pipe, the carburetor with WOT, the crankcase breather & the radiator. Whichever one(s) hiss at you is (one of) the faulty system(s). Tail pipe = exhaust valves, carburetor = intake valves, breather = rings, & radiator = (we hope), head gasket.

If it has sat for a while, especially in a humid area, the rings maybe stuck. If this is the case, try putting a 1/2 cup of Marvel Mystery Oil, (MMO), down each cylinder.

After setting the pistons about 1/2 way down the cylinder, use a tube of some kind to get the MMO into the cylinder, not on top of the valves. Next let it soak for a few days to a week, the longer the better. Leaving the spark plugs out, spin the engine over until no more oil squirts out. It will be messy, put some rags over the spark plug holes to catch the oil.

Now start the engine & run it until there is no more blue smoke. This can a take a minute or five. I like to drive it around for a bit after this, but this is not necessary. Re-do the compression test. Did the numbers come up? If so, drive it for a while & monitor the situation. If not, new rings are in the cards.

You live in PA, is the area of PA you live in a humid area, does steel rust there quickly?

I have replaced the rings on a L-134 without pulling the head studs. Cleaning the block is tougher & it takes more care not to damage the pistons or rings, but it is doable. However, there is zero chance of damaging or breaking the studs off. Your call.

Your list of tools is fairly complete. You will also need a ring groove cleaner, some use a broken ring for this. I own a ring groove cleaner, so I do not. A piston ring expander is a very useful tool it makes installing the rings onto the piston much easier. As I am sure you are aware, many FLAPS & some machine shops will rent or loan these out.

IHTH, Cpt Logger.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Agas46cj Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug. 2022 at 4:04am
I bought it off the for sale page here. Supposedly it was driven fairly often around the farm it lived in. It drives great up to 35-40 mph then falls on its face. I’ve rebuilt the carb and did a full ignition tune up, set the gaps, changed the fluids. It runs a little better with that. I did a vacuum timing adjustment. Gets great vacuum, 22”. That didn’t seem to change it’s driving characteristics. So I did a compression test and found it’s fairly low for living at 350ft elevation. Bruce suggested the wet test so I followed through on that and my compression much improved. I don’t know when in it’s history it got the supersonic. Had I known that it had that, I didn’t even know that the supersonic was an engine, I may have not bought it. It’s not my first tear down or rebuild of carbureted engines. However it is my first flatly. My intentions for it are to be able to start and drive it whenever I want, maybe take it to some 4x4 parks around here. No parade quality. I knew it needed body and transmission work and I’m experienced in both. I’m not too in love with the super so I’m not too upset to tear it down. I work as a cnc maintenance and service tech and have a habit of fixing things I find questionable. I considered the bleed down, but I would only be confirming things I already plan on repairing. My hope when I bought it was to enjoy it for a month or 2 with all its rust before I blew it apart. This just means I’m ahead of schedule, not a bad thing. I like to post questions for things when I’m not %95 or more sure of things. Being my first flat head I have plenty of questions. And I finally figured out how to post photos. This software on an iPhone is cumbersome. I really appreciate the wealth of knowledge and helpfulness I see And get from the cj2a community. It makes buying my dream vehicle more enjoyable, so thank you for all the advice and replies. 

Edited by Agas46cj - 05 Aug. 2022 at 4:08am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bight Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug. 2022 at 8:44am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote muley Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug. 2022 at 9:26am
Originally posted by Agas46cj Agas46cj wrote:

I’m not too in love with the super. 
 
Aaron, stop knocking your SS. Of all the engines that get swapped into these little beasts, the SS is one of the most desirable.Wink
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cpt logger Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug. 2022 at 10:00am
I am with Muley on the Supersonic. It is a great fit & gives you a tad it more power than the original engine. Most folks will not be able to tell that this engine is not stock. Heck, many Jeep nuts will not spot the differences.

Now if you just have to have an original engine, put this one in "The Trading Post" section & offer to swap this Supersonic for an original engine. Someone will want to trade. If I had a spare L-134 Go Devil, I would make that offer.


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