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74 620 L20 spun crank bearing - now I'm looking to rebuild/swap


daderaide

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My fiancé and I finally got moved into our new place and my truck spun a crank bearing. I guess it's great since I've been really looking forward to doing a swap ever since I got the truck a little over a year ago and I FINALLY have a nice big 2+ car garage to work in. It doesn't come at a very good time financially but I guess things like this never do. Anyway, I've been lurking on the forum for a while but haven't had much to input. I feel like I can finally do a write up/project thread! I'm wondering what folks think about my options, given what I'm looking to accomplish. I don't have a ton of money but I do have a lot of experience. I put myself through engineering school as a master tech and have been consistently doing side mechanic jobs ever since. Most of my swap experience has been on hondas though. This will be my first Datsun build. Here's what I'm looking for:

 

1. I'm working with a tight budget. Probably $1000

2. I really hate carburetors. If it's at all possible, I would really LOVE a fuel injected engine. Even throttle body injection would be better.

3. I am currently without a welder. I've had my eye on a new TIG welder for a few months but there's no telling when I'll finally be able to order it.

4. I see this as an interim, stop gap swap until I save up enough to do something really awesome a few years down the road when I'm not trying to get married, etc. and have more money to play with.

5. I'm not in a HUGE hurry, but I would like to finish it before Canby this year. (I'm guessing current availability is going to be a pretty significant factor in this decision)

6. I'm NOT afraid of fabrication.

 

So, I see my options looking like this:

1. rebuild my current engine if the block isn't too damaged

2. buy another running L20 and throw that in there

3. build some kind of franken-motor like the long rod 2.1L motor or maybe a Z24/L20 hybrid

4. add throttle body injection from the z22/24i to my current engine after rebuild (if I can find it)

 

If I end up finally getting a new welder and IF I can find the parts within the budget, the dream would be to swap in a KA or even a VG. That option seems like it has too many "if"s attached to it to be realistic though.

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A ka swap will definately go over a 1000 dollar budget but it definately checks off everything else in your list.

A member here by the name redeye sells swap mounts for 620 ka swap that look absolutely top notch, and have a very attractive price tag to boot!! I'm in the middle of my swap and have to say it's mostly been pain free.

 

I'm in for a build thread!

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A ka swap will definately go over a 1000 dollar budget but it definately checks off everything else in your list.

A member here by the name redeye sells swap mounts for 620 ka swap that look absolutely top notch, and have a very attractive price tag to boot!! I'm in the middle of my swap and have to say it's mostly been pain free.

I'm in for a build thread!

A truck ka24e could come within budget if he took his time to find a good deal. That's probably the best bet for timeframe and cost.

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$1000 is not going to get you far in this situation. It would certainly be enough to fix the problem, but if you could stretch it a bit, you could use that money to bring you into the new millennium.

 

I almost guarantee you will spend more than $1000 fixing what you have. It's the snowball effect.

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How much do you have invested in yours so far? maybe i could convince my fiancé to let me have a little more in the budget...

I'm putting a ka in a 610 goon, so far 540$ I think, I will have to get my driveshaft made up yet, and my friend will be making the harness work free of charge, but where I live typically a 240sx ka will run 7-800 for the full swap with 5spd on it's own. Maybe they are much cheaper in other parts of North America.

hell, if you do all of your own fab work you might get away with 1000$ ka swap if you find a cheap motorset and nothing needs replacing when you start it up

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I hear stories like that all the time of people finding things of almost free. Somehow that's never me. My resources are limited to either craigslist, pick-n-pull or here. I'm sure I could watch things like a hawk for the next year and a lucky deal like that might come along, but I'd like to have my truck back before then. I might be able to squeeze $1500 for it. especially if it's over a few months time.

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I believe the cheapest, and fastest would be to pull your engine, and evaluate how bad it is.  Just involves removal, and dissassembly, not much cost, only time.

 

You said fiancé.  When is the wedding, in relationship to your time frame of making Canby?  Something for you to consider.  This might also be a test of how your future wife is going to react to you working on old cars.

 

Your stated options.

1. rebuild my current engine if the block isn't too damaged

2. buy another running L20 and throw that in there

3. build some kind of franken-motor like the long rod 2.1L motor or maybe a Z24/L20 hybrid

4. add throttle body injection from the z22/24i to my current engine after rebuild (if I can find it)

 

Removing and inspecting your engine will determine if number one is even possible.

Number two option is a possibility.  Requires some research, and a bit of luck.  But that would be cheapest, and quickest, if your engine is not rebuildable.

 

option three, and four, I think will exceed your budget of both time and money.  Remember a more modern FI engine will require a welder, for new motor mounts, and a transmission with the right clocking, or tilt to fit the truck.

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Fabrication will be tough.. without a welder.

 

KA swap in your truck will run you over $1000 unless you get the swap parts for basically nothing. Your going to need mounts, drive shaft, flip the center link.. would be dumb to not do the clutch. Wiring, relays, oil, gear oil, filters, good idea to regasket anything that is leaking on the KA. Front and rear main..

 

Good now you have your KA. But your brakes are shit.. 

 

 

Things to think about.

 

Buy a running L20.. toss it in. $300 and your back to driving it in a weekend. Take that $700, buy a KA and slowly buy other needed parts. Then swap... and sell the L20.

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:rofl: LOL if only you guys knew her. She loves this truck almost as much as I do. She'd sell her own car before she'd ever think about letting me sell the truck. I'll be handing it down to my children some day.

 

I know replacing with another L20 is definitely the cheapest, but it pains me SO MUCH to put in all that work and money and end up with exactly the same thing that I was dissatisfied with before. Maybe if I only spend a couple hundred on a replacement L20 I could spend the extra $$ on a throttle body injection set up.

 

 

Fabrication will be tough.. without a welder.

 

 

I've seen a few folks talk about members on here that make motor mounts for the KA swap. Are there solutions for the other fab parts also? trans crossmember, etc?

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Well, I can't blame you at all for wanting to go with the KA. If that's what you want by all means make it happen!!

 

Under $1000 is probably not gonna happen though. Also, upgrade your brakes during or before the swap. :)

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I know replacing with another L20 is definitely the cheapest, but it pains me SO MUCH to put in all that work and money and end up with exactly the same thing that I was dissatisfied with before.

 

Better buy a Ford ranger pickup with Fuel injection.

 

more to this than just bolting up a FI injected manifold. oil pan issues ectt theres really more to this than pne thinks esp if not experince in wiring

 

carbed L motor will always get you home

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except when it left me stranded on I5...

 

I put myself through my BA in electronics engineering by working as a master tech. I'm not afraid of work, wiring, or fabrication. I've wired several fuel injected honda engines into cars they were never meant to be in. I don't expect that to be a problem for me. What I don't want is spend a lot of time and money working on something that I don't enjoy driving.

 

It sounds like the consensus is that almost no mater what, anything I do is going to cost more the $1000 except for a straight replacement, used L series. :crying:  Unless I get really lucky and find a motor for free.

 

If that's the truth of the matter, I really don't have much choice but to accept it. 

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I do not know what good a L-18 crank will do in a L-20-B engine.

 

I too would love to have a reasonably modern fuel injection in one of my 521 trucks.  I am thinking 1996-2000 vintage.  Something OBD2.  It would be nice to get in my 521, and to start it, push in the clutch pedal, and turn the key.   No more guessing, based upon the current temperature, and how long since the last time it ran, how many pumps of the gas pedal, how far to pull the choke, how soon to push the choke back in part way, and knowing that if it is running good cold, it is probably too rick, and raw liquid gasoline is washing oil off the cylinder walls.

 

My ski boat has a fuel injected engine.  The engine is pretty much self contained.  You supply electrical power to the engine, the computer gets what it needs, a fuel pump sucks gas out of the tank, and a second fuel pump pressurizes the fuel rail.  Crank it, and it starts.  No pumping the throttle. 

 

Wiring a basic fuel injection system does not to me seem all that difficult.  The big issue with cars is the emission controls.  The cat converter.  The evaporative emissions system.  Making sure all the sensors see the information they need to.

 

The problem with a four cylinder L-engine is the manifold, and fuel injectors.  Once those two hurdles are crossed, the rest should be reasonably easy.

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He says it's a 74 and that should be an L18 in it. L20Bs were only in the '75 and up. The build date can read July '74 to June '75 and this would be a '75 model year truck with an L20B

 

Maybe the engine was already swapped? Look on the driver's door tag for the date of manufacture and then on the enging block just behind the dip stick handle. It should say L18 if a '74 and L20B if '75

 

What needs to be addressed is why a rod bearing spun. This is almost always lack of oil. These old Datsuns need more attention than to-days cars. There is no electronic voice telling you the oil is low. It needs to be checked at least weekly and if the engine starts making strange noises, stop and find out what is wrong. A spun bearing gives lots of warnings, long before it goes out. If this isn't looked after the next engine will suffer the same fate.

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It has an L20 transplanted from something else "sometime in the 80's" as was told to me by the guy I bought it from about a year and a half ago. It's definitely an L20. It's stamped on the block. He only did the engine though and still have the original 4-speed manual. I'm pretty certain it ran low on oil. I was driving back to Portland from a trip to Bend when I heard the telltale squeak/screech and knocking sound. I stopped immediately but the damage was already done. No oil light and I checked the oil before I left Portland for Bend at the beginning of the day. I guess it was burning/leaking oil faster than I thought. 

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