Oyaji

Dandy then. If they confidently offer their product for use on public roads (and do not include a disclaimer "FOR OFF-ROAD USE ONLY"), then presumably they either have engineering expertise in-house or have at least outsourced it, and that should be good enough. . This thread has piqued my curiosity about 7075 aluminum - I should make some time to read about it.

The canister contains activated charcoal, which adsorbs hydrocarbon vapors and readily releases them again into the fresh air drawn through it by a running engine. Even after 25 years I expect it is still performing its intended function. . If you do remove it (because you can get away with it in your locale), note that you must provide some method of safely venting the fuel tank. In the years before the charcoal canisters this was done with a vented fuel cap. If you rely on the stock venting line after removing the canister, vapors will vent into the engine compartment where they might be ignited by a stray spark... with potentially explosive consequences (and from what I've heard, it wouldn't be the first time that happened, either!). . I don't think vented fuel tank caps are available anymore (nor that any ever were for screw-on caps for cars with evaporative emissions canisters). If you do go the modifications route, for safety make sure to not only plug off the venting line to the engine compartment, but to also provide a check valve in your gas tank vent to limit leakage in case of a rollover accident.

No worries at all, Earl. I was just voicing a concern that is outside my direct experience, so I was trying to not sound authoritative while still getting the idea across about something that is pretty darn important. . Any time you are offering automotive parts for sale - especially modified/non-stock - you have opened yourself up to huge liability. It thus is in your very best interest to do serious engineering review, and to specify limitations/applications/warrantees. I would expect that the company offering this part has done so, and a review of its stated applications should give you an idea of its roadworthiness. . If they don't explicitly state that it is for highway use, then I wouldn't use it because there too much at stake to risk failure. It isn't purely a matter of strength, you see - with regard to metal fatigue it is a matter of how many cycles of vibration it can stand.

:D

Will the stock drivetrain handle 400 lb-feet of torque? Does anyone here know its torque limit? and what the weakest link in it is? . Keep in mind that the drivetrain torque limit will reduced by increasing tire size over stock, too... . Interesting project - please keep us updated.

Well, I kinda thought the conclusion would be self-evident, but I'll try to spell it out a bit more clearly: for someone considering a change in material for a steering item, there may be more to consider than just how well a "memory aluminum" offers a return to original shape when bent under off-road conditions... for instance, if it will be driven on public roads and if having the steering linkage remain connected at highway speeds is at all important to the driver. In such a case, knowing about metal fatigue just might be an important consideration! ;) . I repeat that I don't know about the characteristics of aluminum, but I have heard that its fatigue life is a quite important consideration in airplane design. You might want to make sure that the manufacturer certifies their product for highway use.

. You're talking about metal fatigue here. Failure is on a logarithmic scale, which means that the difference between hundreds of thousands and millions of cycles (and more) between failures is a very small increase of material. For steel at least, proper design can offer infinite fatigue life at very small cost in weight/fabrication/money... I don't know if that holds true for the many alloys and heat-treatment states of aluminum.

:agree: . (For HO - never had a Renix). Personal preference only; I prefer the cadmium(?) plating on the NGKs (and Bosches too) to the zinc plating on Champions because it is more durable. Probably makes no difference to most people, but I am both meticulous and cheap when it comes to spark plugs (and a lot of other stuff too). What most folks would toss in the trash, I refurbish with a file (to re-flatten the center electrode once worn rounded to enhance/rejuvenate spark generation capability).

Since you are having a custom casting made, ask how much it would be for multiple parts made on the same casting run. I expect the cost would be very small, and it should bring the price per part down drasticly if you have the idea that you or anyone else would like to have duplicate parts for more such swaps in the future. . At least ask to keep the match plates (the master jig that is used to make the sand casting molds) - that way they won't get lost in case you ever decide to have more castings made. With the match plates, you could go to any foundry in the future and have a new casting run done.

. Unless you frequently need a tach for general use working on various vehicles, you don't need to buy one. As I mentioned earlier, many/most/all of the auto parts chain stores offer a free loaner tool deal. You put down a deposit on the tool, use it, then return it in good condition and you get your full deposit refunded. . It's a good program they offer - I take advantage of it for tools I seldom need.

That explains why the transmission went walkabout ... . If the tach is correct (and that is still a big IF, right? free check, should do that...), and considering the operating load they placed on that weak-sauce engine, it would have made good sense to put short-leg final drives under it. I wonder just how short they geared it... . I concur with Eagle about what that sort of heavy duty must have done to the transmission... 3 times, right?

. That will just get both valves closed for #1 - you will need to repeat this 5 times (each 120 degrees of crankshaft rotation past #1 TDC) to get each of the other cylinders to top dead center on compression stroke. This is to ensure that both valves for each cylinder are closed and thus that their rockers are maximally slack when you check them. . I guess that you could use how slack the rockers are for #1 as a general indicator of how worn the others are, but since you have the valve cover off, may as well check them all.

. Think about it - no more sturdy than a washer would be. Specialty bolts with bigger heads/flanged bases are certainly available (and are often used for engine and suspension mounts etc) that offer vastly superior strength compared to the rather flimsy plate joining the studs in your picture, but the designers chose to go this route instead. . Consider the assembly effort needed to use hex bolts compared to the stud plate - that's what is behind my guess that its purpose was merely to cut assembly time/labor at the factory. It really is unbelievable they got 70 bux apiece for these in the dealer parts market!

. Don't know, but will make a guess: I don't think the stud plate has any function beyond the reduction of labor during factory assembly. What went together on the line may be different depending on who was working that day! . No guess about vibration: whereas an inline six (along with flat six and V-12) is inherently balanced by design and has zero first and second order harmonics, that is not true of any other engine designs - they do vibrate more.

Note that torque overload is what twists off axles. If you don't overload it, then it will never twist off. . I get the feeling from your poll that you are thinking it is a matter of time (rather than a too-high torque overload event) that will cause breakage. That's like asking "how long is a piece of string?"... or more like "how many months/years can I step on a land mine before it goes off?" - the answer is once, if you step on the trigger hard enough.

. Short answer is "no". . EGR adds a bit of exhaust to the intake air charge (hence the name Exhaust Gas Recirculation) in order to reduce the peak combustion temperature and thereby reduce emission of (various) oxides of nitrogen (NOX is a lung, mucous membrane, and eye irritant; in places subject to poor atmospheric circulation - like LA - it can be a contributor to smog; elsewhere, NOX is virtually unnoticeable); by doing so it robs power from your engine. Running without it you might barely notice the engine running better and very small increases in power and fuel economy (or you might not even notice). . I think it is (finally, for some years now) illegal in all states to tamper with emissions equipment on your engine. Some states do not do require periodic vehicle inspection and many do not do in-use emissions testing, so you may be able to get away with said tampering indefinitely, regardless of restrictions... not that I would ever advocate willingly flouting the law, mind you. :)

. This man is dead-on correct... which is exactly the reason I was asking the questions I asked. I know about the process for certification and the exhaustive testing required to document it, and was wondering just what (if any) has been done, and where to find the results.

As an aside... . Which has a higher factory tow rating - MJ with 10" rear drums or whatever donor vehicle the rear disc brake swap comes from? . More importantly, which has superior load-stopping power on an MJ, the disc swap or 10" drums? Has it been objectively tested? test results posted? if so, where?

. I'm kinda rusty on this - a few years ago I could have answered authoritatively as it was a particular area of expertise for me... but here goes. . Eagle is right about NOX coming from a lean-burn run condition. That puts that reading at odds with HC and CO being high, as they come from rich-burn run condition. O2 sensor should help with all 3 pollutants, and EGR will help with NOX (by reducing peak combustion temperature). . I would bet on a well-tuned 4.0 in good condition to beat emissions limits of that era even without a catalytic converter installed. Two things come to mind that might help you. First is to question the test: is the test actually using the emissions limits in effect at the date of manufacture, and is the calibration of the test equipment up to date? It just doesn't seem right that the test values you reported are correct. Second, if that doesn't get you to pass, then after making sure you have the engine running as perfectly as you can get it (making sure all your sensors and their connections [including grounds] are good, particularly the O2 sensor - checking your cap, rotor, and spark plugs and wires wouldn't hurt either), consider adding an adjustable fuel pressure regulator for tweaks to beat the test. . One last thought - maybe you just need to try a different test facility.

. I think a bumper hitch would handle the light load he mentioned (lawnmower and 6x12 trailer) just fine, though a receiver hitch is highly desirable. . On the extreme end (and I surely don't recommend it), many times I pulled several tons (3+) of agricultural implements by the simple steel step-bumper hitch of an old light 1985 Toyota mini-pickup with the ~100HP 4-cylinder 22R engine and a 5-speed on 20-mile hauls down rural farm-country roads. Careful loading, attention to tongue weight, and low speed carried me through season after season. Pulling was not the problem - I never had a prayer of being able to stop in any sane distance, so I never went faster than 30 MPH. I drove so carefully I pretty much never had to use the brakes.

. Pulling is never the issue - you could pull a much heavier trailer with a 4-banger (just don't get in a hurry). . STOPPING a load is an altogether different proposition, though... especially if you add bigger diameter tires and/or a significant load. I think the best bet would be to look for 10" rear drums, and that means a D44 rear, right?.

. I read a little about that engine, just enough to salivate... . The horsepower is really attractive, though overkill at something like 240 HP. The torque is downright scary though - over 500 lb-feet, right? Enough to twist a little Comanche into a pretzel!

Wait... what? Not at all what I have in the transfer case. :hmm: . Me neither! . This ain't 'zack'ly what I got, but it is near enough to get the idea across - it's the square hole that was wallowed out and where I shoved that finely-tapered hand-whittled wooden shim I mentioned in my earlier post: . . . Square peg was somewhat rounded off too - made never-no-mind a difference with the shim wedged in between the shaft and square mating hole: . . .

Take the sensor/sender off and look at the square hole in it, and at the square stub end of the gear shaft that drives it. If either are rounded off, you can either replace them, or just do what I did: whittle a finely-tapered wooden shim, shove it into the square hole, then reassemble. I have had to do that twice: once at 190,000 and again at 285,000 miles - has worked just dandy.

It's good practice to oil fasteners before assembly to ensure both proper torque when tightening and that the fastener will come apart without twisting off the next time it is removed. Maybe the last time it was assembled the mechanic used plenty of lube. . Any drop of water finding its way in would emulsify with any oil already in there, turning it milky - think of how much vibration the engine makes. . I wouldn't be concerned - those are blind holes into the block, right? Look at their location and direction - if you drilled farther, what would their path intersect, and how far would you have to drill to get there? I don't think you need to worry.