Phantomarine Posted August 8, 2017 Report Share Posted August 8, 2017 Just getting back into the datsun world. I have a '74 620. The L18 is totally distroyed. I have '84 Chevy 2.8 V6. Does anyone know of a way to match it up with the stock 5 speed in the 620? 1 Quote Link to comment
datzenmike Posted August 8, 2017 Report Share Posted August 8, 2017 While I can agree with a V6 engine swap.... mainly because they fit, the GM 2.8 is really a piece of shit engine. Sorry but they are, ask any wrecking yard. No power and the main bearings can't handle what it does make. It's a poor engine choice. But if you insist, surely the 2.8 came with manual transmissions... so get one. There are companies that make adapter plates for engine swaps but then there is flywheel/clutch incompatibilities. Your '74 L18 didn't come with a 5 speed so someone swapped it in? Best bet is replace with an L20B engine. Perfect fit, everything bolts up, wiring, fuel, exhaust, throttle, mounts, rad and transmission. 2 Quote Link to comment
Lockleaf Posted August 8, 2017 Report Share Posted August 8, 2017 Mike is right. That motor is about the most useless v6 you could choose. And no way will it bolt up to your stock transmission. If you insist on gm go 4.3 or 3800. Either is superior. Stay Nissan and go vg30/33 or vq30/35 2 Quote Link to comment
Phantomarine Posted August 8, 2017 Author Report Share Posted August 8, 2017 OK Mike, what are you thoughts of a subaru boxer engine with the stock 5 speed? I have the V6 and the boxer lying around. Since the L18 block is toast, but the rest of the truck is save able. I'm trying to find a stronger yet reliable engine to fit in with the stock powertrain. 1 Quote Link to comment
thisismatt Posted August 8, 2017 Report Share Posted August 8, 2017 Reliable? Then don't use the Subaru motor 1 Quote Link to comment
flatcat19 Posted August 8, 2017 Report Share Posted August 8, 2017 Sell those two motors you have to buy an L20B. Any 620 75 and later came with one. Start hunting. Or maybe actually diagnose why your L18 is "distroyed." 2 Quote Link to comment
Crashtd420 Posted August 8, 2017 Report Share Posted August 8, 2017 Reliable? Then don't use the Subaru motor 1 Quote Link to comment
distributorguy Posted August 8, 2017 Report Share Posted August 8, 2017 If you want to use the 2.8, only use it for the bellhousing, intake, carb, and distributor. Then you drop all that onto a 3.4, for a 40hp gain over a stock L20b. Then you either use the 5-speed that came with it, or make a simple adapter plate to bolt it up to the old trans. If you can't make the adapter plate, you'll have a nearly impossible time performing such an engine swap. Or you build a good L20b with a cam, headers, and a good carb, and you'll get 95% of that power and it bolts right up to your existing mounts, exhaust, trans, etc... Quote Link to comment
datzenmike Posted August 8, 2017 Report Share Posted August 8, 2017 Boxer engines are what? 5 feet wide? One of the worst reasons for an engine swap is that you have one laying around. Your choices are fewer and your decisions are heavily biased. A recipe for future disaster. L series are impossible to blow up if you keep them filled with water and oil. L18s, you just can't rev then to death either. So the most likely thing wrong is a $20 head gasket. I guess it could be just plain worn out too. So, have to ask what is 'totally destroyed' ??? Find an L20B that runs or rebuild it. Say $100 to over bore it, another for pistons and another for rings and bearings. Say $400 to $500 for everything and skip the head for now. The L18 head may be in good shape and you can use that while the L20B head is out getting work done on it. The L20B are more common than an L18 and about 11% larger displacement and torque. The 620 came with L20Bs too, so everything fits with the only real difference being the top of the block is 3/4" taller. Finding one will be the most work, swapping it takes a morning. Next would be almost any inline 4 cylinder and transmission but nothing bolts up from drive shaft to rad, oil pan to air filter. Next is a V6 because of the dual exhaust and size. Fuel injection engines are even more work, so include from the gas tank forward. Yes they can be done, with a lot of cutting maybe even a boxer engine could be fitted but why invent the wheel when there are engines that fit? 1 Quote Link to comment
Stoffregen Motorsports Posted August 8, 2017 Report Share Posted August 8, 2017 Subaru motor won't fit in that engine bay. I have never tried it, but that's my guess. I'm going to give you some advice: never start a car/truck project because you have parts laying around. I built a truck for a guy a few years back based on an axle that he got a deal on. The build ended up costing him about $20K and the axle he bought is now not wide enough for his truck. We are now making plans to replace the narrow axle. 1 Quote Link to comment
racerx Posted August 8, 2017 Report Share Posted August 8, 2017 Sounds like he's trolling trying to emote a response, maybe same guy w different log in name. Who in their right mind would put a sub engine in a Datsun? Quote Link to comment
Crashtd420 Posted August 8, 2017 Report Share Posted August 8, 2017 I even read about a kid who bought a 521 off some one here and said his plan was a VW turbo diesel... made me sad especially since there was really nothing wrong with the truck... I never minded the SR and ka swaps because at least it's still nissan, hell try to fit a titan motor if really you want, probably won't fit... I'd sell all your extra parts you have and put the money into that l18, unless it's total junk .... for the money it would take for the swaps your thinking you could make that l18 pretty sweet.. It would always make me shake my head when an old ford couple has a small block chevy in it.... but that's just me.... Quote Link to comment
Phantomarine Posted August 8, 2017 Author Report Share Posted August 8, 2017 I am strapped for cash and have access to the 6 and the boxer, they are in my possession. Friend say they have them and we're willing to give them to me. I just bought my '74 620, the head is cracked in 6 places between cylinders 2 and 3. The exhaust is white from overheating. With these signs, I'm not sure how much of the engine I can trust. I only considered the other engines cuz they were offered to me for free. I had already planned on rebuilding the one I got, if I got it. If there is a chance to salvage the stock engine, that is what I truly want. I was told it is an L18, but not certain. The U67 head is no good with all the cracks.I know where to get replacement part for the engine and had planned to rebuild it if it is not a total loss. Quote Link to comment
Phantomarine Posted August 8, 2017 Author Report Share Posted August 8, 2017 I'm just concerned of getting too financially deep with this engine to find out I could have gone a cheap way. Quote Link to comment
thisismatt Posted August 8, 2017 Report Share Posted August 8, 2017 You are in Oregon, land of L motors. Surely you can find another one in running condition cheaper than rebuilding & swapping either of those free engines. 1 Quote Link to comment
Crashtd420 Posted August 8, 2017 Report Share Posted August 8, 2017 If your strapped for cash a swap is not the way to go, just a rabbit hole for your non existent money to go down.... those L series motors are pretty durable.... question is what caused the damage to the head... a tare down and inspection should be your first order of buisness, cost for that is zero.. the bottom end might be just fine,.. even if you can't get a head where you are they can be found on eBay for around 500 or so completely rebuilt.. No matter what the least expensive is a rebuild, 2nd replace with another l series, even with free motors those swaps will cost you more, and in ways you haven't even thought about.... 1 Quote Link to comment
racerx Posted August 8, 2017 Report Share Posted August 8, 2017 Have you checked out craigslist or offer up or post want engine on various datsun forums or sites, incl. This site. I just went on Oregon Craig's and seen tons of Datsun parts, I'll bet you will find an L series engine, running or may need a rebuilt. You said that You are strapped for cash? Well putting another type of engine, besides L series, will cost more due to fabrication and set-up. Quote Link to comment
Phantomarine Posted August 8, 2017 Author Report Share Posted August 8, 2017 Well I finally got through all the caked on oil. I do have the L20 block and a straight edge show's the top of the block is level and square. Mike do you think there is a chance to save the block? Just replace the head and manifolds? Quote Link to comment
Stoffregen Motorsports Posted August 8, 2017 Report Share Posted August 8, 2017 Check to see if the block is cracked. They crack around the center head bolt and sometimes can be repaired. 1 Quote Link to comment
Stoffregen Motorsports Posted August 8, 2017 Report Share Posted August 8, 2017 It would always make me shake my head when an old ford couple has a small block chevy in it.... but that's just me.... It's a context thing. Growing up building import engines, I always thought that small block Chevy V8's were the biggest piles of crap on the planet. The quality of the internal parts, the loose fitting rods, intake, heads, all that just made me cringe. So years later I saw an old timer at a gas station, filling up his 46 Ford (with SBC and flames). I asked him what was with hotrodders and SBC's. He replied it was context. In the 50's, the flathead Ford was the best thing out there. Along comes the SBC with one HP per cubic inch (big deal back then), the ability to rev and the overall durability and it totally changed the landscape. Ever since then, I have taken a different view on Fords with Chevys in them. 2 Quote Link to comment
Lockleaf Posted August 8, 2017 Report Share Posted August 8, 2017 Yes there is a good chancev your block is fine. If it's not, you're still in a better place financially to replace it with another. A new head will run you $100 if it's a common version. A gasket set will be another $100. Plus $50 for oil, coolant' shop supplies. Then maintenance items like plugs, wires, etc. Fluids and maintenance will be necessary on any motor you put in so no cost savings there. It really is impossible to swap a motor for less than the $200 ish you need to spend to fix the L series. If you replace the whole motor it might be $400 but regardless still cheaper. Cheap entry fees are not always a cheap exit strategy. Quote Link to comment
racerx Posted August 8, 2017 Report Share Posted August 8, 2017 Maybe all he needs is a rebuilt head 1 Quote Link to comment
Crashtd420 Posted August 8, 2017 Report Share Posted August 8, 2017 Maybe all he needs is a rebuilt head I think its beyond a rebuild... Sounds like the head is cracked.... 1 Quote Link to comment
Phantomarine Posted August 8, 2017 Author Report Share Posted August 8, 2017 I ran all my knowledge with this based on what the seller told me. Now that I'm getting things cleaned up and can see more for myself. I have found that the block is an L20B, the head is is a U67 with 1 crack between the valves in #3 and 60% of the smog has been wrongly removed. The exhaust manifold is chalky white at #3. 1 Quote Link to comment
Phantomarine Posted August 8, 2017 Author Report Share Posted August 8, 2017 I was told, to boost the L20B I can put a Nap Z 2.2 head on it. Can anyone give me an idea how far I need to for that and if anyone has a Nap Z head for sale? 1 Quote Link to comment
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