LFX V6 engine as a viable option? Has it been done?

[mccuistion]

Hey guy, as some of you know I just got my '73 620 and am in the process of piecing together my swap. I am pretty set on an SR20DET or a KA24DE-Turbo build but I just helped a friend do an LFX swap in his Miata and insists I should consider it. I will admit, it is AWESOME in his Miata.

 

I did a few searches and didn't come up with anything, so my question is, has anyone done an LFX V6 swap in a datsun? A 620, 720, 510, anything? If not, is there a major reason why this swap doesn't or wouldn't work? 

 

I plan on getting the exact measurements of the LFX to see if it's even possible that it could fit in the engine bay but not sure if this has already been established? It is a 3.6L DOHC V6 that is pretty wide up top but the exhaust manifolds are cast into the heads so I'm thinking there is a possibility it could fit if the heads clear above the wheel wells and the downpipes are fabricated to fit. I know that anything can be made to fit with enough fab work but I'm hoping to do my swap with the least amount of destruction possible. 

 

Like I said, I will do more searching and measure the LFX soon but I was just hoping to see if anyone had already looked into this and came to a conclusion? I'm still leaning SR20 or KA24 but I have to admit.... a modern VVT 3.6L V-6 with a 6 speed could be really cool and unique in my little datto!

[mccuistion]

I have to say.... the fact that no one has said it has been done or can't be done has peaked my interest. In the next 2 weeks I'm am going to meet up with my friend with the LFX swap and get some measurements. I was dead set on sr/ka swap but if this has never been done it would be very cool to be the first(if possible without chopping the firewall/fenders). My main worry is the width of the dohc heads up top and the length of the tranny from bell housing to shifter, but if those 2 measurements are reasonable I will look further into this.  

[Charlie69]

From looking at pictures of the LFX engine it looks like there might problems clearing the steering column in the 620.

[Stoffregen Motorsports]

The LFX sounds like a very cool swap. Ford Ecoboost V6 would be fun too. At 365hp, stock, I imagine you would never need anything more.

 

That funky built in exhaust manifold is sure to have problems in the future, and doesn't leave a lot of room for mods (custom headers on a conventional setup are easy to build for custom applications), but it is compact.

 

For the steering, it makes sense to get rid of the 620 box altogether and use a box and column from a 720, or build a hybrid column like I did in my 320 balljoint conversion thread. If you're going to modernize a vehicle with an engine like the LFX, it probably makes sense to ditch the kingpin front suspension too. I know I sound like a preacher when I bring this up, but using a whole 720 front clip has many benefits: balljoints, disc brakes, improved suspension geometry,  stronger T/C rods, steering box and idler arm that mount to the outside of the frame (allowing for more room in between the frame rails) and the exposed steering column shaft (also giving more room). These are all huge improvements over the antiquated 620 front suspension and would be fitting for a swap like the LFX.

[mccuistion]

26 minutes ago, Stoffregen Motorsports said:

The LFX sounds like a very cool swap. Ford Ecoboost V6 would be fun too. At 365hp, stock, I imagine you would never need anything more.

 

That funky built in exhaust manifold is sure to have problems in the future, and doesn't leave a lot of room for mods (custom headers on a conventional setup are easy to build for custom applications), but it is compact.

 

For the steering, it makes sense to get rid of the 620 box altogether and use a box and column from a 720, or build a hybrid column like I did in my 320 balljoint conversion thread. If you're going to modernize a vehicle with an engine like the LFX, it probably makes sense to ditch the kingpin front suspension too. I know I sound like a preacher when I bring this up, but using a whole 720 front clip has many benefits: balljoints, disc brakes, improved suspension geometry,  stronger T/C rods, steering box and idler arm that mount to the outside of the frame (allowing for more room in between the frame rails) and the exposed steering column shaft (also giving more room). These are all huge improvements over the antiquated 620 front suspension and would be fitting for a swap like the LFX.

Thanks Charlie and Stoffregen.... 'im starting to really consider a 720 frame or 720 front clip conversion. My original plan was just disc brakes and coilover conversion on the kingpin front end but the more i read and learn from you guys it might be easier in the long run to just start with 720 front end. I'll have to do some research on how difficult it is to take a full 720 frame and drop my 620 body on it...... there is a 1985 720 for CHEAP on craigslist right now, might be worth picking it up. I need to learn more about compatibility before i buy anything though.

[Charlie69]

Buy the 720 while it is there then you can take your own measuremnts and do what you think is best.  Check with your local MVD and see if there are any restrictions on the frame swap.

 

In AZ I will take my 520 when I am done for a level 2 inspection, I will have to show the MVD officer where to find the numbers, he will write down the numbers and run them for being stolen and when the numbers come back clean he will stick a blue MVD sticker on my drivers door jamb and re issue me a title that the new numbers will now be associated to my 1966 VIN.  This way if I get pulled over in California my mixed bag of numbers will come back legal.  I had a 1950 Studebaker Champion impounded from me in 1976 in West Covina California for not having the AZ registration in the car.  I did not have the money to get the car out of impound so I lost it.

[Stoffregen Motorsports]

There are pitfalls with either a frame swap or a frame clip. Insurance companies might not like the frame clip, DMV's may not approve a frame swap. I do both, and have never had problems, nor do I expect problems, but the possibility is always there.

 

You could graft the front suspension onto the 620 frame, but this would take so much precision fabrication (within a 1/16" or so).

 

Others here may tell you that you can bolt the 720 suspension to the 620 frame, and I've seen pics of how they have done it, but it is less than ideal. Sorry to throw you under the bus, guys, but I strive for perfection, always.

[Stoffregen Motorsports]

Sorry to hear about the Stude, Charlie. That must have been heartbreaking.