Jump to content
HybridZ
derekkg

EFI conversion questions

Recommended Posts

Hey Everybody,

 

New member and first time poster here. I just purchased a 71 240z (last weekend!) that has had a pretty decent amount of engine work done to it. Attached is a picture I took about 10 minutes after I bought it.

 

I have some big plans for the car and unfortunately not a ton of time to do them. I plan on taking the car across the country in less than 1 month!

 

The biggest priority and really the only major thing I want to do before the drive is to swap the car to EFI. I think I have gathered a list of everything I will need, but I would appreciate any help!

 

First, the motor that is currently in it:
2.8 F54 block with Flat top pistons from a 280zx w/ 168k miles

P90 from an 82 280zx Turbo with 179k miles

New head and engine gaskets

New water pump

Turbo Oil Pump and Turbo head bolts

280zx distributor and alternator

MSD Blaster coil

Aluminum radiator, electric fan

Dual SU sidedraft carbs

 

After looking at a lot of options, it would seem like my best, easiest, fastest, and cheapest option would be to swap an EFI manifold and intake system from a 75-78 280z and use mostly stock parts, but run it with a MegaSquirt. The other major option I was looking at was using a Throttle body intake, but almost all of those kits seem to cost way too much. Another option seems to be to use a GM throttle body, but the adapter plates I found seem to be much too expensive, plus with dual carbs it seems like I would need 2 throttle bodies, which increases price.

 

So it would seem like I need the following from a 280z:

- Intake Manifold
- Fuel Injectors
- Fuel pump
- Fuel Pressure Regulator
- Throttle with TPS
- Coolant Temperature Sensor
- Intake Air Temperature Sensor
- Air Flow meter
- Cold start valve (Whats that?)
- Air regulator (idle air control valve?)
 
The attached picture is basically where I got this list from.
And then I could run the whole thing from a MegaSquirt 1 with a wideband O2 in the exhaust. (Standalone seems to be easier since it is not a stock motor, plus I am interested in learning)
 
Is there anything else I would need? What should I be looking for? Is this really the easiest EFI swap, or am I missing a much easier one.
 
Thank you so much everybody! Any help is greatly appreciated!

post-45142-0-02806800-1438164728_thumb.jpg

post-45142-0-23723400-1438165568_thumb.jpg

Edited by derekkg

Share this post


Link to post
Share on other sites

I would HIGHLY recommend AGAINST the conversion before your trip. 

Get to where you're going and then get some Patton Machine SU Adapters and a Megasquirt and go from there.

Drive it across the US with the Carbs. I have done this trip three times and never had a problem with Carbs keeping it below 85 in the desert on long uphill grades.

 

You also forgot the Surge Tank and booster pump for the unbaffled tank with no swirl pot.

 

 

If the car runs and drives now, take it on some one and two hour one-way highway trips during the day to shake it down.

If it makes it doing that in the heat of the day, you will be fine crossing the country with it. A tank of gas only lasts about 2 hours anyway. . . I refilled every 240 or 280 miles with about 10-12 gallons each time at speeds around 75-80 the entire way.

Share this post


Link to post
Share on other sites

i would second these guys in saying a swap of that nature right before a trip is asking for trouble. You seem to be looking for the cheapest route in addition to being easy but i have to say that my EFI route of bolting the MSD Atomic EFI Master Kit to a 4bbl intake (sold new by Arizona Z) can be done in your drive way in a day or 2 with no major mods to the car if you've got simple hand tools and a couple biddies. If you have a car lift and said buddies you can probably get it done in 12 hours or so. Good luck with whatever route you decide on, the owner over at Patton is a really nice guy and puts out some awesome stuff.

Share this post


Link to post
Share on other sites

 71 240z

 I plan on taking the car across the country in less than 1 month!

 

 

First, the motor that is currently in it:

2.8 F54 block with Flat top pistons from a 280zx w/ 168k miles

P90 from an 82 280zx Turbo with 179k miles

New head and engine gaskets

 

 

Dual SU sidedraft carbs

 

 

So it would seem like I need the following from a 280z:

 
- Intake Air Temperature Sensor
- Air Flow meter
 
- Cold start valve (Whats that?)
- Air regulator (idle air control valve?)
 
And then I could run the whole thing from a MegaSquirt 1 with a wideband O2 in the exhaust. (Standalone seems to be easier since it is not a stock motor, plus I am interested in learning)
 
 Is this really the easiest EFI swap, or am I missing a much easier one.

 

I pulled all of the "red flag" statements from your post.

 

That engine combination is an odd one, not what an experienced "Z" person would put together unless they had planned for a turbo. (EDIT - actually, with the flat tops, that's a typical ZX engine.  8.8 CR.  My mistake.)  Makes you wonder.  The "new" head (not rebuilt) makes me think it came from California Datsun (formerly Datsun Parts LLC), one of the only suppliers around, but one who hasn't mastered the art of the Z.  I wouldn't drive one of his engines or heads across the country without making sure everything was in spec.  "New" just means clean and worked on.

 

SUs can be finicky and many people spend a lot of time getting them dialed in.  Considering the odd assembly of parts you have it would be surprising if they were ready to go.

 

The air temperature sensor is in the AFM already (on most AFM's).  But most people don't run an AFM with Megasquirt.  The cold start valve is described in the FSM.  This kind of shows where you're EFI knowledge is at this point.  Most people have a hard time learning EFI, so learning EFI from scratch, and Megasquirt, and getting it all sourced, and installed, and tuned, in one month is really a ludicrous proposition.

 

Michael Wales says that his EFI swap can be done in a couple of days but it took him a month and a half just to source all of the parts.  His buddies probably knew something about 240Z's or cars in general also.  Forget about 12 hours.  

 

Finally, it's a 1971 240Z.  The rest of the car is probably worn out too.  Best to focus on bearings, and bushings, and transmission, and all of the other parts that get hot and fail on long road trips.

 

If you do get lucky and make a choice and source all of the parts you need in just a few days then you could revisit the idea.  But you'll probably get stuck on just finding a 280Z intake manifold.  Don't disassemble anything on the engine until you have all of the other parts you need.  

 

Odds are though that you're going to find a problem on your new car that throws a wrench in to all of your plans.  The EFI swap will be irrelevant.

 

Welcome.

Edited by NewZed

Share this post


Link to post
Share on other sites

If your cross country trip brings you through Colorado and you have some spare time I would love to talk over the Megasquirt setup with you.  I would ditch the AFM, oem cold start valve and idle control valve.  Start simple in that area and use a newer on/off air valve until you start to get more understanding of the EFI system.  Then start playing around with nice to have features.  

Share this post


Link to post
Share on other sites

I also recommend Megasquirt. I've wasted many hours fiddling with the old wiring harness and ecu. Megasquirt will simplify things for you.

 

You will want to either install a surge tank or do a baffled fuel tank swap. I recommend the surge tank as the 240z return lines are pretty small for the FI application.

Share this post


Link to post
Share on other sites

Wow! I got way more responses than I expected. I'll have to be more diligent in checking this.

 

First, there were a few things that I didn't make clear, and a few details I should have added that would have helped clarify my situation. My mistake, I will attempt to clarify in my responses below.

 

Also, today I found somebody close by who is willing to sell me all of the following for a very reasonable price. It's all from a '76 280z:

 

- Intake Manifold (with injectors)
- Air intake temp sensor
- Water Temp Sensor
- Air Flow sensor
- Throttle body
- Fuel Pressure Regulator
- Fuel Pump
- Gas Tank (should be baffled)
- ECU

 

As far as I can tell this will be most everything I need to get a really good start parts wise.

 

I also ordered a wideband O2 sensor and gauge. My thinking is no matter what method I choose it will be useful. I can see it being helpful if I stick with carbs for tuning, if I use the '76 ECU I can see how well it can manage the pieced together motor, and if I go standalone (MS) I will need it for closed-loop operation

 

I would HIGHLY recommend AGAINST the conversion before your trip. 

Get to where you're going and then get some Patton Machine SU Adapters and a Megasquirt and go from there.

Drive it across the US with the Carbs. I have done this trip three times and never had a problem with Carbs keeping it below 85 in the desert on long uphill grades.

 

This is good to know! What route(s) did you take? I am mostly concerned about altitude performance. We are starting in the Bay Area of CA and taking a southern route and then heading up to Rochester, NY to end it. I am afraid that between mountain passes, hot deserts, and humid south, the carbs might be a little difficult to work with. Carb tuning is also not my specialty. I am much more familiar with fuel injection. Sounds like it is possible to get some pretty reliable operation from the carbs though!

 

You also forgot the Surge Tank and booster pump for the unbaffled tank with no swirl pot.

 
Awesome! Thanks for the catch, I actually found a tank that I think will work, see above
 

 

If the car runs and drives now, take it on some one and two hour one-way highway trips during the day to shake it down.

If it makes it doing that in the heat of the day, you will be fine crossing the country with it. A tank of gas only lasts about 2 hours anyway. . . I refilled every 240 or 280 miles with about 10-12 gallons each time at speeds around 75-80 the entire way.

 

Other details I didn't think to mention:

I bought the car in Reno, and then immediately drove it back to the bay. Started in Reno, drove over Donner Pass in a rainstorm, and then drove all the way back to the bay. 5.5 hours straight with no serious issues after sitting for a couple of months from the PO. Not a bad first impression

 

Other pluses I didn't mention:

- Toyota 4 piston front calipers

- New rear wheel cylinders

- Aluminum radiator and electric fan (It stayed at the middle or lower the whole way back, even through Sacramento

- New drive shaft

- Ground control coilovers (This was a bit confusing from the PO, I think they were ground control lowering springs on MR2 stock rear struts and 240z rear struts in the front)

- New suspension bushings everywhere. They are all red and hard, so I am assuming polyurethane

 

Also Tony, I can't help but notice you are from Reno. That is a shame, I wish I had known about you earlier, I could have taken it there to get a more experienced view on it.

Also, I am trying to track down the owner who built this. I have a lot of questions, but unfortunately the kid I bought it from lost the previous owner's information sometime in the 4 years he owned it. Do you know anyone in the Reno area who built a Z like this 4-5 years ago?

Share this post


Link to post
Share on other sites

i would second these guys in saying a swap of that nature right before a trip is asking for trouble.

Just curious, what would you say is the biggest source of trouble? Are you saying the fuel injection itself is troublesome and carbs are better? Or just the tight timeline to do the swap before a major trip is asking for trouble?

 

 

You seem to be looking for the cheapest route in addition to being easy but i have to say that my EFI route of bolting the MSD Atomic EFI Master Kit to a 4bbl intake (sold new by Arizona Z) can be done in your drive way in a day or 2 with no major mods to the car if you've got simple hand tools and a couple biddies. If you have a car lift and said buddies you can probably get it done in 12 hours or so. Good luck with whatever route you decide on, the owner over at Patton is a really nice guy and puts out some awesome stuff.

Thanks! I am seriously considering a 4bbl Throttle body injection kit also. It looks like it will be a little out of my budget though. Some craigslist parts might bring it back down though

Edited by derekkg

Share this post


Link to post
Share on other sites

That engine combination is an odd one, not what an experienced "Z" person would put together unless they had planned for a turbo. (EDIT - actually, with the flat tops, that's a typical ZX engine.  8.8 CR.  My mistake.)  Makes you wonder.  The "new" head (not rebuilt) makes me think it came from California Datsun (formerly Datsun Parts LLC), one of the only suppliers around, but one who hasn't mastered the art of the Z.  I wouldn't drive one of his engines or heads across the country without making sure everything was in spec.  "New" just means clean and worked on.

 

Ah, that was my mistake, I didn't phrase that very well. When I said "New head and engine gaskets" I meant it had a new head gasket and new engine gaskets. Sorry.

 

 

SUs can be finicky and many people spend a lot of time getting them dialed in.  Considering the odd assembly of parts you have it would be surprising if they were ready to go.

 

The car was running pretty rich when I got it (at 4500 ft) in Reno, but it ran well. It leaned out a little when I got it back to sea level but it still runs pretty rich. Like I said in my response to Tony though, it made it on a ~ 5 hour journey with no major problems.

 

 

The air temperature sensor is in the AFM already (on most AFM's).  But most people don't run an AFM with Megasquirt.  The cold start valve is described in the FSM.  This kind of shows where you're EFI knowledge is at this point.  Most people have a hard time learning EFI, so learning EFI from scratch, and Megasquirt, and getting it all sourced, and installed, and tuned, in one month is really a ludicrous proposition.

 

oh, I didn't know that the temp sensor was in the AFM, that makes sense. I am thinking about using a stock ECU also, so I am at least considering using the AFM.

 

Finally, it's a 1971 240Z.  The rest of the car is probably worn out too.  Best to focus on bearings, and bushings, and transmission, and all of the other parts that get hot and fail on long road trips.

 

I forgot to mention this in the original post, but I mentioned it in response to Tony above. Wheel bearings are all quiet, suspension bushings are all recently replaced with what appears to be new poly bushings. The transmission shifts well (although the synchros on 3rd seem to be gone)

 

 

If you do get lucky and make a choice and source all of the parts you need in just a few days then you could revisit the idea.  But you'll probably get stuck on just finding a 280Z intake manifold.  Don't disassemble anything on the engine until you have all of the other parts you need.  

 

I think I may have just found those parts earlier today. See my response to Tony above. I think I may have found most of the mechanical parts I need for a swap locally for a great price. Thats great advice though, I should definitely get all the parts I need together before I start taking it apart and make it non running 

 

 

Welcome.

Thanks! This forum seems really active and helpful!

Share this post


Link to post
Share on other sites

If your cross country trip brings you through Colorado and you have some spare time I would love to talk over the Megasquirt setup with you.  I would ditch the AFM, oem cold start valve and idle control valve.  Start simple in that area and use a newer on/off air valve until you start to get more understanding of the EFI system.  Then start playing around with nice to have features.  

Awesome! Right now we are planning on going south and maybe up Route 66 a little, so I doubt we will make it to Colorado, but plans may change.

 

Interesting. You are saying to use a more modern air measurement like a MAF? And for idle control a simple on off valve will work? Does the megasquirt still control this? Do you have any examples of one?

 

Thanks again!

Share this post


Link to post
Share on other sites

I also recommend Megasquirt. I've wasted many hours fiddling with the old wiring harness and ecu. Megasquirt will simplify things for you.

Really? You are saying megasquirt will be simpler than using a '76 ecu? I can see it, there aren't many components a megasquirt needs to run. How difficult is it to get a good baseline tune on the megasquirt? Can the autotune feature do that for you?

 

I am also thinking about swapping to the 76 ecu first, and then swapping from there to megasquirt, just so I can know what it should run at before going to the standalone. Is it harder to get the 76 ecu to work rather than just going straight to a megasquirt though?

 

Either way I am getting a wideband installed, so that should help me monitor the fuel management

 

You will want to either install a surge tank or do a baffled fuel tank swap. I recommend the surge tank as the 240z return lines are pretty small for the FI application.

Like I said to Tony, I found a source for a 76 fuel tank locally. That should be baffled I believe.

 

I recommend the surge tank as the 240z return lines are pretty small for the FI application.

Really? Are the 240z return lines capable of FI? What would the drawbacks be?

 

Thanks!!

Share this post


Link to post
Share on other sites

Awesome! Right now we are planning on going south and maybe up Route 66 a little, so I doubt we will make it to Colorado, but plans may change.

 

Interesting. You are saying to use a more modern air measurement like a MAF? And for idle control a simple on off valve will work? Does the megasquirt still control this? Do you have any examples of one?

 

Thanks again!

 

You do not need the air flow meter or mass air flow.  Megasquirt normally runs as speed density and only requires a manifold air pressure sensor (MAP) which is part of the megasquirt box.

 

I use one of these air valves from an Rx7 for fast idle on my simple setups. 

http://atkinsrotary.com/store/images/D/N332-13-720Detail.jpg

Share this post


Link to post
Share on other sites

You do not need the air flow meter or mass air flow.  Megasquirt normally runs as speed density and only requires a manifold air pressure sensor (MAP) which is part of the megasquirt box.

 

I use one of these air valves from an Rx7 for fast idle on my simple setups. 

http://atkinsrotary.com/store/images/D/N332-13-720Detail.jpg

 

Ah right, I forgot about that. 

 

Cool! thanks!

Share this post


Link to post
Share on other sites

If it did all that driving, put all your EFI Crap in the hatch and put it on when you get to the other end of the country and have all winter in the garage to work on it.

 

I would spend time re-checking mechanical security of things and getting them right in the month before the trip, like brake pads and shoes, ball joints, bushings, investigating the third gear synchro that will have you holding it in gear until it's time to be in fourth... etc.

 

If it ran that far, I wouldn't dick with it at all until you are done driving to the other side of the country. You're just asking for trouble IMO.

  • Like 1

Share this post


Link to post
Share on other sites

And let me put it this way: I can put the stock L28 EFI on just about any 240Z in a weekend and having it running and driving. If I had a car that was running and driving on the carbs just fine, I would stick with them rather than adding EFI. Last thing I want to do on a cross country trip is refit carbs to make it the rest of the way home. I'd just as soon go with what is working well and then play with it on the other end.

Heck, I can put Datsun 75-78 EFI on most Corvairs in a weekend.... I've been doing that conversion since 1979! I MIGHT go with THAT conversion, because Rochesters on air cooled heads are NOT SU's on an L-Series!

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...