Oyaji

.I thought about getting what they call a "half cut", which is just the front half of an XJ cut off and shipped here from overseas. Evidently it is the easiest way to get what you need. The beauty part is that since it cannot be put on the road, it is classed as "parts" for import. Would probably need to get 2 though, just to have a parts source! I wonder what the total cost would be including shipping... . Cost seems to be prohibitive for any diesel alternative, but for someone who intends to keep his vehicle on the road for the long term (like a Comanche owner, for instance :)), I figure that eventually fuel savings would pay for the swap. . Eagle's cam swap idea seems to make the best sense so far, practically and financially. But I can't help but think that a diesel would be the perfect swap for a 1986 with a 2.8L V6.

Interesting comments so far guys - keep 'em coming. . I am gonna toss out my choices one at a time and let you pick them apart. Let's start with the OM 617. Pros: acceptable performance in automotive application (revs fast for a diesel), a lot of them around, reasonable price, great reputation for economy and longevity. Cons: not-so-hot-horsepower, it's a non-stock conversion, needs adapter plate, a little heavier than the 4.0 (iirc 600 pounds), old diesel technology (maybe this is a pro, not a con?). The OM617 engine family was a straight-5 Diesel automobile engine from Mercedes-Benz used in the 1970s and 1980s. It is closely related to the straight-4 OM616. Starting in 1978, a turbocharger was fitted to engines used in the 300SD. With some Mercedes-Benz 300D/300SD diesels already exceeding 500,000 miles, and a few nearing 1,000,000, the OM617 is considered to be one of the most reliable engines ever produced, and is one of the key reasons for Mercedes' popularity in North America in the 1980s, as it was economical, relatively quick (compared to most other diesels on the market) and was trouble-free, unlike the Oldsmobile LF9 diesel V8. . The OM617.951 was introduced in 1979 and displaced 2998 cc, using a 90.9 mm bore and 92.4 mm stroke. Power output was 125 hp (91 kW). Torque was rated at 180 lb·ft (244 N·m). Applications: 1981-1985 300SD Turbo 1981 300TD Turbo . Then there is the VM 2.5. Pros: lighter weight, used overseas in stock XJ application, good torque, mechanical injection. Cons: hard to get in the USA, ditto for parts, just-adequate anemic horsepower. 2.5L TurboDiesel VM 425 2499 cc (153 CID) I4, OHV Diesel 114 hp (85 kW) @ 3900 rpm 221 lb·ft (300 N·m) @ 2000 rpm VM Motori 425 OHV 1994–2001

. I had no idea that sort of economy was possible with a 4.0. I am not familiar with the Jasper motors - are they strokers that use the old carburetted-6 crankshafts? I can see how that would add bottom-end grunt... . Since you have put thought into them, let's talk more about diesels. Provided the torque and weight of the new engine are kept in the ballpark of the 4.0's, I don't see how frame strengthening is required. What engines have you considered? Automan has suggested that with careful driving he might well be able to better his Renault 2.1 TD's 30 MPG to 35 MPG...

. Now there is a thought! Dropping the peak torque RPM would allow re-gearing/taller tires and add efficiency at cruise speed. Over 100,000 miles the best I have been able to squeeze out of my all stock 92 XJ was 22.5 MPG highway at 50-55 MPH, but more generally 20.5 MPG at 65 MPH. The jump from 20 to 25+ MPG is quite a big one, but the jump from 20 to 30 MPG would be enormous... yet achievable with a diesel, I think. What I am after is the biggest gain attainable with an engine swap/modifications. . I still can't get past the thought that a more modern engine with 1) overhead cam(s) 2) variable valve timing and 3) significantly lighter weight would get me even better economy, so I am curious to explore alternate engine options further. . Still, changing the camshaft may well be the best, simplest, and cheapest option. Does anyone have any recommendations on manufacturers and cam grinds?

Let me preface this by saying straight at the outset that I am unsure whether I will ever get around to actually doing this... . I'd like to come up with an engine swap for a Comanche that would offer reasonable torque (say in the range of 2.5 to 4.0 liter performance), but at significantly better fuel economy than either of those stock engines. Said swap option should not be terribly complicated, and target fuel economy would be 25+ MPG. Because they are inherently balanced by design, I'd prefer an inline-6 - and one with 7 main bearings at that, but realistically I fear that is out of the question. Said engine should be available from junkyards - low price and high numbers available would both be pluses. Weight should be no more than the stock weight of the 4.0 + 10% (~600 pounds) - less weight would be an advantage. For gasoline engines, some sort of variable valve timing is highly desirable, and fuel injection mandatory. For diesels, mechanical injection is preferable to reduce complexity inherent in the wiring of CRDs. . Some ideas I have kicked around are the 2.1 Renault and VM 2.5 diesels (easy swaps, but parts hard to source), and the Mercedes Benz OM 617 5-cylinder. The Cummins 4BT swap is just too damn heavy, and so is beyond consideration. I have seen a site that showed a 2.8L CRD swap, but it looked overly complex (though I suppose transmission and transfer case swap along with the engine might make this worthwhile?). How about gasoline options - any ideas? . Just approach this as a thought experiment, and feel free to pitch out your ideas for critique and discussion - thanks guys.

. I am with you here. . Wood was originally used in coachwork because it had been traditionally used for making... coaches. Steel was just too expensive and hard to come by in quantity (until industry ramped up to meet demand). . I've never been a fan of fake anything (wood on a car, non-structural columns in architecture, fake titties on a woman, you get the idea), and instead have always been of the "form follows function" school of thought. Just my opinion - they say there is no accounting for taste, so have at it. :)

I agree that it is a good thing to know - it can get you home when your clutch pedal goes useless... but it ain't a good thing to do all the time for the reason I mentioned above. . Here is a good video that shows how synchronizers work (serendipitously, it just happens to use a disassembled AX15 as the example). When you consider the excess demand on them when making less-than-perfect shifts without the clutch, you can better understand wear on the sync rings.

:agree:. . While a perfect shift is no problem, the synchronizers are only supposed to handle braking the inertia of the rotating driveline mass with the clutch disengaged, so less than perfect shifts without unclutching put a load on synchronizers they were never designed to handle. When shifting without the clutch, if you are off in matching engine speed to ground speed, then the synchronizers are trying to make up the difference by fighting both the inertia of the engine and the momentum of the truck to get them matched to be able to engage the gears without grinding.

. Not a Strongbad reference, but a bad impersonation. . But since you mentioned him, here is my favorite clip :rotfl2: :

. Not working for me - I tried using the "Link" and "Image" options as well as just pasting the URL into the body of the message, like so: . What am I doing wrong? Using the full editor? . edit: well, it just worked here, but it didn't work a minute ago when I tried to edit a post - what gives? . second edit ; I think I figured it out - the editor doesn't like the stupid periods it makes me add just to get line spacing between paragraphs (for that matter, if I don't first type a period and then back up and start typing to the left of it, I don't even get spaces between WORDS, no matter how many times I press the spacebar). . It's working now - thanks!

Any updates to be had on this topic?

. Yeah, I reckon he means music (but the "wife" thing was funny :D ). . I hear that out there in Texas, y'all have BOTH kinds of music - county and western! *badda bing* . Here is a funny country song by Ween, titled "Piss Up A Rope": .

. I really hate to say it, but I really feel the need to point out that, since you insist on going your own way, you really should invest in one of these: . . . because this is the direction you are heading: .

The purpose of the two relays is to be able to run the FOG lights off a tap to the parking lights, so you can run them either with the low beams or -- in REALLY heavy fog, when even low beams create a blinding reflection -- with just the parking lights. But ... when the tap is from the parking lights, the FOG lights will stay on with either high beams or low beams. The second relay is wired normally closed (on), and tapped off the high beam circuit. When it sees current, it opens and turns off the FOG lights. Study Skidoo's diagram carefully. He didn't tap off the parking lights, he tapped off a circuit that's controlled by the ignition switch. Doing it his way, you don't even need the parking lights -- and the fog lights will automatically go off when you turn off the ignition. It doesn't matter if the first tap is off the ignition or off the parking lights. It's the second relay that turns the fog lights off when the high beams are activated. . Just the conclusion I came to in the posts that followed the one you quoted - take a peek at those that follow, and you'll see I pointed out the flaw in using the ignition to power the first relay with regard to compliance with the law. . My lack in comprehension came from only having used relays in the past to CLOSE a circuit - never to OPEN one. A close look at Skidoo's circuit diagram was indeed enlightening. I agree that the cost of the second relay is justified by offering a fail-safe isolated secondary lighting circuit.

Well pull the power off the tail light cicrut to control the switch in the cab. It would meet the requirement and keep it isolated from the headlight switch. . Roger that. Since tail lights are on a separate circuit from high and low beams, it would meet the letter of the law to use them (in place of the ign tap shown) to energize the first relay.

Skidoo gave you the wiring diagram. You need to BUY two (2) relays. The way to wire your lights is to wire them according to Ski's diagram. And I don't care what you want to believe, if you have driving lights and you wire them like fog lights you will NOT be legal. . Say - since the current draw required to trip the switch in the relay and keep it closed is small, is there really a need to use 2 relays? Seems there would be enough reserve capacity in the circuit to allow tapping into one of the low-beam wires behind a headlight and using it to energize the relay. . What is the energizing current requirement for those automotive relays - not more than a quarter amp, right? I've always piggy-backed a relay to power another circuit just as I have described, by drawing minimal energizing power from the parent circuit itself. Energizing a relay to energize another relay to power the auxiliary circuit seems unnecessary and wasteful to me, to be honest. Would that maybe be to power a much larger relay needed to supply a LOT of current for more than 2 high-power lights? What am I missing?. If what you're asking is if rather then using a second relay powered by the high beam circuit to turn off the fogs lights vs using the low beam circut to power the switch that controls the first relay then yes you could do that and eliminate one relay, the down side to powering it in this manner is you then could only use your fogs when your low beam circut is enabled. So no just fog option, or no back up lights if you have a fuse or circut go out on the factory lights. I've had my headlight switch go out twice prior to isolating highs and lows to relays too, . . Yes indeed, that was what I was getting at, alright. . Going back and looking carefully at your 2-relay diagram, I now see the advantage you describe. When the high-beams kick on, the second relay wired to the high-beams OPENS the circuit, cutting off the supply current to the fog lights Nifty, to be sure, for it allows the fog lights to function if the headlights fail while defeating their use with the high beams. . But... the way I read your diagram, lights wired that way will still operate in the absence of low-beam and/or tail lights - which is contrary to this requirement: (1) Fog lamps are general illumination lamps as covered in 19VAC30-70-160 D. They must burn through the tail light circuit even if on a separate switch. If installed on a vehicle with a four-headlamp system or a vehicle equipped with driving lamps, they must be wired into the low beam circuit. Am I missing something again?

Skidoo gave you the wiring diagram. You need to BUY two (2) relays. The way to wire your lights is to wire them according to Ski's diagram. And I don't care what you want to believe, if you have driving lights and you wire them like fog lights you will NOT be legal. . Say - since the current draw required to trip the switch in the relay and keep it closed is small, is there really a need to use 2 relays? Seems there would be enough reserve capacity in the circuit to allow tapping into one of the low-beam wires behind a headlight and using it to energize the relay. . What is the energizing current requirement for those automotive relays - not more than a quarter amp, right? I've always piggy-backed a relay to power another circuit just as I have described, by drawing minimal energizing power from the parent circuit itself. Energizing a relay to energize another relay to power the auxiliary circuit seems unnecessary and wasteful to me, to be honest. Would that maybe be to power a much larger relay (with higher than a 0.25 amp engergizing demand) needed to supply a LOT of current for, say, more than 2 high-power lights? What am I missing?.

. LOL - no man, you are on track and have, in a commendable effort to help, only posted the pictures that RedWolf has either not recognized or ignored. :wall: Since he had posted a picture of the very same part (from a different angle) originally only to have it ignored or not recognized, Hornbrod is just pointing out that his patience is exhausted - and I don't blame him one bit. Ya just got to laugh it off, or blow a gasket, or run screaming from the thread, or SOMETHING to keep from busting wide open. :rotf: . Any bets that this thread will run to 150 posts before the issue gets correctly resolved? (Oh, man, I love these smilies/emoticon options here!) :banana: .

. . whoops! You posted while I was looking for a better.gif and failing. (by the way, that there is a mighty fine .gif)

Buckaroos, if y'aint seen his vid of the rolling frame on the last page of his build thread, well, y'oughta - it is a thing of beauty: . I've always been a perfectionist and hard to please, so I think it takes a lot to impress me. Welp - he blew me away. Only possible flaw I noticed is the way he attached his towers to the frame for the front springs and shocks - and he came up with a nifty double-tube over-the-engine brace joining the towers to make up for the weakness. Seems to me he could have trouble where he welded the towers to the frame - I am curious as to how they will hold up to abuse, if the deep curves in his double-tube brace connecting the towers will prove sufficiently stiff or will flex, and if he will need to add gussets to beef up both them and the frame welds at the tower bases later. . But ye gods! what attention to detail and concerns often overlooked by builders!.

That's awesome. I'm guessing from the 113 number that'd be FSAE Michigan? I'm with the University of Saskatchewan team, Huskie Motorsports, and while I think the team's been to Michigan once or twice, we usually go to FSAE Lincoln (formerly California). Don't know if I'd be allowed by the team to post a build thread on here (we're incredibly careful about what gets published) but the build usually is fairly well documented on Facebook (https://www.facebook.com/huskiemotorsports) and we typically put up a video or two on the YouTubes (http://www.youtube.com/HuskieMotorsports) every now and again. There's a bunch of stuff from the last couple years on there, if you want to check it out. I've posted a couple of the videos in the pub section before, shortly after they came out, but didn't get too much interest. We've got a couple guys pretty well dedicated to getting our name out this year, so I'm expecting that the number and quality of videos is going to increase, but we'll see. . When I was involved there was only Formula SAE (competition took place outside Detroit at Auburn Hills), plus some sort of off-road competition as well (I don't recall the name of that one - "SAE Baja" sumpin'-or-other?). I am glad to hear the program ended up so popular that they added a second event. It's an awesome way for students to get experience - they never fail to impress - and also to make contacts in the car business for job-hunting after graduation. I don't know if you realize it, but the judging before the driving competition days is (or was at Detroit, anyway) well-attended by managers who are scouting for outstanding talent. (Out of the ~500 students in attendance, I saw 2 guys get offered jobs on the spot - there may well have been more I didn't see.)

To be honest, I had never heard the name except when going to the local Advance Auto Parts store and being asked every time, "Is that for the 4-liter 6, or the Iron Duke?". I have been using it with poetic licence for a few years. I now stand corrected. *hangs head in shame* . Thanks for the clarification - it is a favor to point out an error, and I appreciate it. :)

. Actually, no - the bet was back on page 3 ;): . . Better get crackin' - only 7 more posts to go 'til 100! :teehee: .

. Better hurry, then - just 9 more posts to go 'til 100!

. Ummm - that's premature ebullition! He isn't done until he has bought the relay and installed it. . 14 to go, and counting... :popcorn: . Am I missing something? :hmm: I thought by the pics above it was mission accomplished? :dunno: Have I been Duped...... :fs1: . Och, aye, I reckon you did not read "ye olde fine print"... . 12 to go, and counting!