Newly acquired 78 620

[Mesk1]

Hello Ratsun, been lurking for a bit doing my research. Got a 78 620 off my uncle. Has a 4 speed along with a L20b than needs to be rebuilt. Engine has been partially disassembled and has sat in the bed of the truck for over 8 years. I am currently in a dilema deciding whether I should Ka swap it or rebuild. as far as ka swap goes, from what I gathers I need a truck ka for easier install. So my question is since I have not seen any discussion about it, can I get a hardbody and swap everything over? Will transmission fit? That's my main concern to be honest. Any info or guidance on where I can research this particular scenario will be greatly appreciated.

Don't know if this link will work but here are some pictures.

https://imgur.com/a/qm5rire

[datzenmike]

I think a KA engine would get you on the road sooner. The KA's 5 speed won't exactly fit without the driveshaft being lengthened? slightly but a drive line shop does this for a reasonable rate. You will need a high pressure fuel pump and convert the electrical to EFI. Steve...   ]2eDeYe ... one of the mods here, makes and sells custom KA engine mounts for 620 engine swaps,  so there's a big headache taken care of.

 

Welcome to Ratsun.
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[]2eDeYe]

Welcome to ratsun, looks like a solid 620. :)

 

 

The hardbody KA and trans will swap right in with my mounts. The engine wiring harness is a bit of a pain in the trucks as it is integrated into the truck wiring harness.

 

There is a lot of answers in this thread and the links within it.

 

http://community.ratsun.net/topic/39780-620-ka24-motor-mount-brackets/

[Mesk1]

 

I think a KA engine would get you on the road sooner. The KA's 5 speed won't exactly fit without the driveshaft being lengthened? slightly but a drive line shop does this for a reasonable rate. You will need a high pressure fuel pump and convert the electrical to EFI. Steve... ]2eDeYe ... one of the mods here, makes and sells custom KA engine mounts for 620 engine swaps, so there's a big headache taken care of.

 

Welcome to Ratsun.

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Thanks for he info Mike, I have a hardbody to go check out today, it’s runs but haven’t seen it in person. As soon as he gets back to me I’ll go check it out and report back. I’m not looking to make this thing a drifter or anything, just want to use it asap. Solid reliable winter daily (az gets ridiculous hot, we break the 100s this week) unless I can machine brackets for the ac but I’ll get to that when I cross that road.

[Mesk1]

Welcome to ratsun, looks like a solid 620. :)

 

 

The hardbody KA and trans will swap right in with my mounts. The engine wiring harness is a bit of a pain in the trucks as it is integrated into the truck wiring harness.

 

There is a lot of answers in this thread and the links within it.

 

http://community.ratsun.net/topic/39780-620-ka24-motor-mount-brackets/

Thanks buddy I’ll have another go st reading the thread, i skimmed through it when the Datsun was still at my uncles. I have read that the hardbody harness is a pain to extract. Which I really don’t mind but if there is an easier way I’ll jus grab the harness off a 240 along with the intake. I’ve wired Honda’s before So the wiring does not intimidate as long as I have schematics to reference to. I’ll deff need those mounts when I find a swap and start my build thread. I’m documenting everything step by step for future reference. Thanks again.

[]2eDeYe]

The easy ways are 240sx intake ECU and wiring or go to carbureted if you were so inclined. 

[racerx]

Depends on your budget, knowledge, budget, room to work on truck..like a garage, time you have and patience.

[Mesk1]

Came down to Mexico for doc visit and to hit my pop’s homie’s scrap yard . Picked up a truck KA24DE today. They will have it pulled for my dad to pick up Wednesday. So the heart done, what tranny do you guys recommend to pursue for least headaches? Guy told me to just let him know which one and he would call his contacts. He did laugh at me though when I asked if they had 240sx trannies and intake manifolds. Progress moving good :) also, what ecu am I looking for here? The truck with the ka was auto. I have searched and probably slipped by me but all y’all go the hard route with 240 ka

[datzenmike]

Get a D21 Hardbody 5 speed. Closest to the 620 length.

[Farmer]

Or a Napz transmission. Same length

[Mesk1]

Will research both options thanks guys, it's cool if I update here right?

[Mesk1]

Get a D21 Hardbody 5 speed. Closest to the 620 length.

Mike has anyone that used one of these reported success? I’ve never dealt with rwd so cutting a driveshaft seems a high dollar operation

[Farmer]

Napz doesn't require drive line mod and keeps the correct angle

[datzenmike]

Yes the 720 5 speed is a perfect fit I just went with the stronger Hardbody one that comes with the KA engine.. Yes a 720 Z series transmission would be easier in every way. Jest be sure it's the longer 31.5" in length.

[Mesk1]

Farmer, took me some reading to figure out what the napz tranny was

[datzenmike]

The 240sx 5 speed is about 4" longer than the 620 4 or 5 speed. It may also move the shifter back some but the driveshaft has to be shortened.

 

The '81-'86 720 Z20, Z22, Z24 gas engine 5 speed will drop right in with a KA engine. The only thing is the 720 transmissions were sometimes a 26" 'shorty' so you don't want that. Another transmission is the second gen '80-'83 S110 200sx. These cars also came with a Z series engine and a transmission that will fit the KA.

[Mesk1]

The 240sx 5 speed is about 4" longer than the 620 4 or 5 speed. It may also move the shifter back some but the driveshaft has to be shortened.

 

The '81-'86 720 Z20, Z22, Z24 gas engine 5 speed will drop right in with a KA engine. The only thing is the 720 transmissions were sometimes a 26" 'shorty' so you don't want that. Another transmission is the second gen '80-'83 S110 200sx. These cars also came with a Z series engine and a transmission that will fit the KA.

You the man Mike! Gonna go with the napz but will still write down a hardbody one in case one doesnt turn up.

[Mesk1]

Local guy has 86 5 speed unknown miles but tested for 225 and a 95 5 speed 150k miles also 225. Will have a look sometime during the week

[Charlie69]

Get the fly wheel throw out bearing and fork for the trans also.  throw out bearings and frorks stay with the transmissions,

[datzenmike]

Actually the throw out bearing collar stays with the clutch that it's matched to so if you get everything from the flywheel back you're ok. Car KAs use a 225mm clutch while truck KAs use a 240mm clutch. A truck KA trans used on a car clutch requires the car bearing collar be put on it.

 

I would get the truck flywheel/clutch/PP as it's a 240mm (look up the 'White Bunny' clutch up grade on line... it allows the 280zx and 300zx turbo clutch unit to fit a 240sx) but grab the release bearing and collar! This way you can use any transmission you like.

[]2eDeYe]

Local guy has 86 5 speed unknown miles but tested for 225 and a 95 5 speed 150k miles also 225. Will have a look sometime during the week

 

 

As long as the transmission is the 31.5" version, either will work without drive line modifications. 

[Mesk1]

Awesome, I know I saw a thread where a dude posted the correct way to measure. Will look for it throughout the day before heading to check em out. Also all the other stuff I need with it too thanks for that info.

[Mesk1]

Actually the throw out bearing collar stays with the clutch that it's matched to so if you get everything from the flywheel back you're ok. Car KAs use a 225mm clutch while truck KAs use a 240mm clutch. A truck KA trans used on a car clutch requires the car bearing collar be put on it.

 

I would get the truck flywheel/clutch/PP as it's a 240mm (look up the 'White Bunny' clutch up grade on line... it allows the 280zx and 300zx turbo clutch unit to fit a 240sx) but grab the release bearing and collar! This way you can use any transmission you like.

Thanks mike, that white bunny would be overkill for street driving right? Was just gonna go with a stock truck clutch. I know the KA24DE I picked up is off an auto trans and it does have the flywheel, that won’t work with the d21 or napz tranny right? Completely forgot about the dam flywheel clutch stuff

[]2eDeYe]

The stock truck clutch is plenty.

 

The rocket bunny kit is essentially using the bigger truck clutch. 

[datzenmike]

Thanks mike, that white bunny would be overkill for street driving right? Was just gonna go with a stock truck clutch. I know the KA24DE I picked up is off an auto trans and it does have the flywheel, that won’t work with the d21 or napz tranny right? Completely forgot about the dam flywheel clutch stuff

 

Automatics have a flex plate rather than a flywheel. If an automatic you will need a manual flywheel. Again trucks are 240mm and cars used the 225mm pressure plates and clutch. If going with a car flywheel you will need the matching release bearing collar for it to work.

 

Also automatics have a cover on the end of the crank that needs prying off if fitting a manual flywheel. The end of an automatic crankshaft also won't have a pilot bushing in the end so get one of those too. About $4.