149 engine teardown for cam replacement

[dodge trucker]

Originally Posted by J-Mech

I do. I have one that goes down to 5ftlbs.

I also have an inch pound that only goes up to like 50, and I also have a 3/4" drive that goes to 600ftlbs.

I have at least 4 torque wrenches....that I remember.

Yup so do I.... but you and me aren't the ones doing this particular job that the thread is about.... that question was meant for the OP.

People don't realize but converting units of torque is often one of those ideas that is better on paper.

Without looking back within the thread, I think there was some in/lb measurement that came out to (something like) 23.6 ft/lb. I'll use that figure for argument's sake.

In/lb. is a much "finer" scale than ft/lb. which is kind of "coarse".

The whole reason for torqueing something to a certain setting is to control distortion, tighten evenly/equally, stretch the bolts to optimum and not beyond, and also to not "strip" any threads. Sometimes you can go past that prime point of "tight" and not realize that something is starting to strip out until it is under stress, from thermal heat/cold cycles to mechanical "work". If not done right, you might as well use a plain ol ratchet and socket. Sometimes approximating by using a coarser scale, isn't any better than not using a torque wrench at all.

I, too, have several torque wrenches from the old Craftsman beam style, to 3-4 clickers in between, up to (probably the same) 3/4", that goes to 600 ft/lb that Jon has. I have both in/lb and ft/lb and even a fancy expensive digital one that I can change units on, just by pushing a button. The snap on guy really liked me that day, ha ha....

One thing to keep in mind here, is that most torque wrenches are NOT ACCURATE in the lower 20% OF THEIR SCALE> which often starts somewhere other than zero.
On one of my Snap on clickers, it goes from 20lb to 250 ft/lb. So 20% of 250 would be 50 ft/lb. But the scale starts at 20.
so 250-20=230 lbs of "scale" 230/5= 46. so for the 1st 46 lbs of scale that torque wrench isn't as accurate as it is in the top 80% "of scale". So we add 46 to 20 (the lowest the scale reads) we come up with 66 ft/lb. That is the lowest reading to which that torque wrench can be "trusted. almost 3x the "converted" in/lb. to ft/lb number that you are dealing with on that rod spec. and then if the reading is to be 23.6, how do you know if you got 22.8 or 25.1 ft/lb? and are both exactly THE SAME? Sometimes "close enough," isn't.

I completely understand, we all had to start somewhere, and most had basically "nothing" when we did start working on things (some had access to tools at work, or at Dad's garage, or the neighbor, whatever) and I also completely understand not wanting to buy a tool to be used one time and then collect dust. Been there many times as well. BUT when we set out to do a job, we set out to do it right, the best that we can. and in a case like this, if the job doesn't last, most likely nobody will get physically hurt (tractor engine blows up, you hear a boom... but no bloody limbs and such) but the time it takes to do it right (and I am glad to see you asking questions to help be sure it is, in fact, right) isn't much more time than to do it haphazardly... but the difference in results, and how long they last, can be HUGE. I myself hate redo's. Yes you still learn from having to redo a job, and maybe more so than it everything turns out like you hope and expect it to. but for what it costs to have to redo something, that's what hurts....

I'm saying all of this because though Jon hammers on some of the details like your piston to wall clearance, there are certain fasteners that need to be tightened "just right". and by converting in/lb to ft/lb and the result being that low on the chosen scale, it is extremely hard to be accurate.

In this case you would be better off begging, borrowing, or (no, probably not stealing) a torque wrench of the scale you need for the job at hand.
At very least I'd be watching garage sales, auctions flea markets and such for some of these tools that you need but not all that often. if only for "next time".
I am NOT AT ALL a fan of Harbor Freight but in a case like this for what you think might be a 1- time deal they can be handy. Never know, if youre like the rest of us your 149 won't wind up being your "only" Cub, you'll use this stuff again!!!

Having said all of that, I appreciate reading threads like this of somebody "digging in and getting their hands dirty" instead of today's mentality of either A) "throw it away and get a new one" or B) "let someone else do it for me, and I'll just write a big check"...and it appears by your questions, you know your limitations/ believe me, we all have them.... but for all the work it takes to do a job like this, if you want it to last another 20 years, heck even 5 years, you gotta do things right.
The most important fasteners to torque "the right way" on one of these engines, is the rod. The head comes in a close 2nd. so all that said, I wish you luck on your project, I hope it holds up for as long as you need it to and maybe beyond. but if it doesn't, just remember things like this....

[J-Mech]

While you make a really good case, and explain it really well..... it's not that big a deal. I've done a lot of these motors. I just convert to ft lbs if it goes beyond my inlb torque wrenches limit. I've used the bottom end of the scale so many times on my small 3/8" click type Snap-On wrench it's silly. I have never had a failure that was a result of over or under torquing. I'm sure that if you put a wrench on a test stand, it would confirm that they aren't as accurate... which is likely why they tell you that, but here's something I do know: I too spent big dollars on a digital Snap-On torque wrench that is supposed to be accurate all through the scale since it uses a sensor, and not a spring. When torquing with it, you can visually watch the scale, and it lets out a beep (which I can seldom hear) and also vibrates in my hand. Once you have reached the torque, the screen displays the max torque you put on the fastener. I have never had it land EXACTLY on the torque I was shooting for. Sometimes it goes off just before the proper torque is reached, sometimes it goes over. It is pretty amazing to see when doing a head on say a DT466 IH motor, how far apart it shows you are torquing. Maybe 15 pounds difference between bolts. Now, that is at the top end of the scale, but I think you would find there is so much variance between when you feel that wrench click (if that is the style you are using) and what it actually torques as there is on that digital wrench. If you take an old beam style wrench and compare it to a new digital, you would find very little difference between them. While I agree that torquing is important, how it gets done really has little consequence, at least in this application. Now, the newer stuff is a little more sensitive. Sheared rod bearings and powder forged cranks are just more sensitive. Besides, now they have went to almost all torque-to-yield fasteners anyway, so you have to get a new bolt every time you torque it. (Stupid.) This old Kohler was engineered in the days of beam wrenches and the slide rule. Whatever wrench he used is likely no worse than they had at the time it was new. I'm confident it will be fine. I've done too many things not to be sure. What's important is he torqued it.

[mickb72]

I used the installation of a head on a Kohler as a way to check calibration between my wrenches. A 30 year old beam,3/8 HF and a 1/2 Carquest Pro Value.Very very close, which i would call equal. Which do i trust the most? The beam. Mike

[jbrewer]

Good post Dodge.


Another alternative to China Freight is buying good used commercial tools. Over 40 yrs of wrenching I've bought a pretty complete set of US made tools, and they're always a pleasure to use and will outlast me.

Ebay, Garage Journal, CL, etc are all good sources of affordable well made tools. Having the right tool for the job always feels better than rigging something to make it work and doesn't have to be all that expensive.

Bob, you're doing great!

[RLause]

Does anyone get their torque wretches re-calibrated? When working for Teledyne, all measuring equipment had to be re-calibrated on a regular basis.

[jbrewer]

Originally Posted by RLause

Does anyone get their torque wretches re-calibrated? When working for Teledyne, all measuring equipment had to be re-calibrated on a regular basis.

Since I'm not selling things to the government like Teledyne, I just check one against another (I've got several from a Craftsman beam to a Tool Truck and a commercial US made one with a federal stock number ob it) . They're quite close.

Teledyne has a bigger profit margin than my wrenching produces (which in dollars is 0$, but in therapy is quite valuable)

[J-Mech]

Originally Posted by RLause

Does anyone get their torque wretches re-calibrated? When working for Teledyne, all measuring equipment had to be re-calibrated on a regular basis.

Only a few times. Unless I suspect a problem, I don't. I had one fail one time torquing a head. I thought it was pulling too hard and not clicking off. Broke a head bolt. Since then I randomly check them against another wrench.

Edit:
Supposedly, the digital wrenches never need calibration. According to my Snap-On man, they will tell you if they have a calibration error.

[dodge trucker]

my most recent Snap on and mac guys have the calibration checker on their tool trucks for customers to be able to use any time.
I do check my clickers, now and again. my co worker found his to be "way" off back about 4 months ago so sent it in to be recalibrated.....

[Mr Bob]

Once again I want to thank all that are posting to this thread. I started drag racing in the 60's and 70's. Had a 63 Chevrolet belair with a 283 engine. Bought several books on rebuilding car engines. Every thing I knew back then was self taught. I tore the engine down in the fall each year and went through it and replaced any thing I felt was out of spec. I bought a Craftsman torque wrench back then. I did not have a lot of extra money back then, nor do I now. I used that wrench to torque the rods, main bearings and head bolts. Never had a failure using that wrench. Never blew an engine. So I thought nothing of using that same wrench on this engine. I did not know it could be so far off converting inch pounds to foot pounds. They are torqued and I am going with that. Did buy a Harbor Freight torque wrench that is in inch pounds. Did not read the shop manual close enough or I just plain forgot that I would need over 200 inch pounds reading. Another Senior Moment. I have them a lot. Did a preliminary adjustment of the valves today. Caught something that I should have caught years ago. I have an old set of feeler gauges. I think it goes from .001 to .040. I was setting the intake valves to .009. My .010 blade is messed up so I tried a .011 blade to see if it would slide in between the valve and the tappet. Lo and behold it slid in easier than the .009 blade. Found a couple more blades that evidently were mis marked. I had used this gauge for years setting points on my motorcycles. Can't believe I didn't catch that before now. Got the oil pan on and torqued down today. Also got the dip stick and oil fill part installed. Going to have to put engine on a Harbor Freight 4 wheel dolly that I rigged so that the engine will sit securely. Getting too heavy for me to be lifting. Going to buy a multimeter that beeps so I can set the points while on work bench. Will recheck valves and points once the fly wheel is on so I can be sure of the timing marks. Have a great day.
Bob

[dodge trucker]

Ok a couple of things here, with the torque wrench thing, a car engine rod main and head bolts are spec'd out in ft/lb so that was right. But when you're racing 1/4 mile you measure time in seconds and portions thereof, you don't use minutes and try to judge how long it takes to cover the distance, right? Same idea of ft/lb to in/lb when measuring tightening specs. I see that though dated, you do have some mechanical experience that still applies. Just having to deal with 1 cylinder instead of 8. It should be fine, like has been said. But as I am going thru the process stuff like that kinda bugs me.
Now that said, I admit that I don't torque everything that can possibly be, on one of these engines, but I do on the critical fasteners.