New project arrives this morning

[johnymd]

I was under the impression that the sr20 and mx5 1.8 engines and boxes were pretty much identical weight wise. Engines: sr20 = 136kg, mx5 1.8 = 131kg.

If you have better info on complete engine/box weights then I’d like to here.

I would agree that the sr20 would be a much nicer swap but I here it requires frame modification to fit. My preferred choice of engine would be a period Datsun engine like a u20. I’d like around 150hp if I’m going to swap and really don’t want to start cutting the car.

If I just highlight my current direction for this car then you can see my think (but please don’t stop the suggestions or ideas from coming).

My current favourite car is the ratty silver/grey 240z. I love the look and originality and don’t care its underpowered. It’s a hoot to thrash around in and ultra reliable and simple. I want the roadster to be the same. Keep the original look and spend very little on it. Fix the brakes and get it running. Current engine is not an option anytime soon (but may go back into the car in the future). I have a good complete mx5 engine and ready to go that could be up and running in a few weeks with no body/chassis mods and a minimal cost. This should give me a reliable sunny day car and if I don’t open the bonnet then who will know. I can leave all the existing roadster wiring as is and just use the coil feed to power a stand-alone engine loom (same as I did in the ratty car) which is totally reversible. I put a battery on the car yesterday and everything works so no need to touch the existing wiring.

I need to keep things simple, quick and cheap so I can carry on with the other Zed’s I’m building.

 

[Alphabettispaghetti]

A u20 would be great.

I weighed an sr20de at 120kg, the mx5 engine is heavier, not as rev happy and has always felt a little 'lacking', IMO!

 

[johnymd]

May have been the det at 136kg. I think there’s no dought the sr is better but I still love the mx5 I have and think this engine in the lighter roadster would be great.

 

[johnymd]

Actually not a big difference in weight.
Mx5 = 980kg
Roadster = 950kg

 

[Rushingphil]

Plus, MX5 engines and parts are very cheap and plentiful - and easy to modify

 

[johnymd]

It will need to come out anyway so might as well be now.

 

[Ian Patmore]

Jonny is right, while the SR engine would be great, it’s not a straight fit. In the US, a roadster specialist who does a lot of these swaps, has a jig to rent out so you know where to weld your engine mounts/frame cut. Jonny would be doing this without any back up it’s in the right place. Plus there is quite a bit of fabrication to do=time.

The stock R16 makes 96 hp, and even in that form, can be a nippy fun car to drive. Been in a passenger in a stock 100hp R16, it had just properly set-up/attention to detail. The R series was designed to run at a higher rpm than its predecessor, the G15.

The U20 (2000cc) is a great engine, 135hp for the US and 150hp for the JDM and Australian market cars on 40mm Solex’s. Head design very good, no need to do any porting as it flows very good. But, it can be expensive to rebuild, as the engine design is a bit on a limb, as in very little/or no internals common to other engine series’ (e.g. R, H and G have some common parts/inter swap).

Jonny (you probably know this already), the ball joints and spindles wear, so check they are good. There are reproduction ball joints and spindles now, which makes them a much more affordable than the Nissan originals, and made to high standard. The can sometimes be a little slack in the steering box. Usual bushes to check. Suspension, probably the shocks are shot, Koni make a good set. The suspension system relies on regular greasing, there are grease nipples around. This maintence is often over looked long term, so this is where the wear in the system occurs. Brakes, the stock system if well cared for can be good, especially with a decent pad material. Can be expensive to repair, as the pistons un-bolt for the caliper frame. There is a Volvo swap, I can’t remember what model, which gives you a little more pad area on the front. The dual brake master can be expensive to replace. Check around where the brake master fits to the bulkhead, as there sometimes can be cracks found/or deforms due to the force applied when braking with your foot. There is a little kit sold to strengthen this area.

Keep up the good work.

 

[Paul_S]

Jonny is right, while the SR engine would be great, it’s not a straight fit. In the US, a roadster specialist who does a lot of these swaps, has a jig to rent out so you know where to weld your engine mounts/frame cut. Jonny would be doing this without any back up it’s in the right place. Plus there is quite a bit of fabrication to do=time.

The stock R16 makes 96 hp, and even in that form, can be a nippy fun car to drive. Been in a passenger in a stock 100hp R16, it had just properly set-up/attention to detail. The R series was designed to run at a higher rpm than its predecessor, the G15.

The U20 (2000cc) is a great engine, 135hp for the US and 150hp for the JDM and Australian market cars on 40mm Solex’s. Head design very good, no need to do any porting as it flows very good. But, it can be expensive to rebuild, as the engine design is a bit on a limb, as in very little/or no internals common to other engine series’ (e.g. R, H and G have some common parts/inter swap).

Jonny (you probably know this already), the ball joints and spindles wear, so check they are good. There are reproduction ball joints and spindles now, which makes them a much more affordable than the Nissan originals, and made to high standard. The can sometimes be a little slack in the steering box. Usual bushes to check. Suspension, probably the shocks are shot, Koni make a good set. The suspension system relies on regular greasing, there are grease nipples around. This maintence is often over looked long term, so this is where the wear in the system occurs. Brakes, the stock system if well cared for can be good, especially with a decent pad material. Can be expensive to repair, as the pistons un-bolt for the caliper frame. There is a Volvo swap, I can’t remember what model, which gives you a little more pad area on the front. The dual brake master can be expensive to replace. Check around where the brake master fits to the bulkhead, as there sometimes can be cracks found/or deforms due to the force applied when braking with your foot. There is a little kit sold to strengthen this area.

Keep up the good work.

Wow, good info!

 

[johnymd]

Thanks Ian, I think I need all the help I can get as their doesn’t seam to be a lot of parts available for these cars. This is half the reason why I’m not doing a restoration on it.

Engine bay is now completely clear so I’ll try and fit the Mazda engine and box tomorrow. I’ve had some mounts made but I’m certain they will need a little tweaking to get them to work. Planned out the new engine loom today. I’m going aftermarket ecu and full race spec engine harness. I’m aiming for a running car by the end of next week.

 

[johnymd]

Engine and gearbox mounts done so engine and box in. Started on the brake by using a 240z brake and clutch master cylinder. Still wiring on the engine wiring harness and fuel system. Lots on parts in the postal system.

 

[richiep]

You don't mess about, do you Johny!? Your ability to crack on with projects makes me jealous!

 

[Rob Gaskin]

You don't mess about, do you Johny!? Your ability to crack on with projects makes me jealous!

Remember 'Scrapheap Challenge' ? You would want John in your team.

 

[johnymd]

Not quit sure I like the word scrapheap used in my threads but I’ll assume there may be a compliment in there somewhere.

 

[Huw]

Fabulous progress Johnny, amazingly amazing!

 

[Rob Gaskin]

Not quit sure I like the word scrapheap used in my threads but I’ll assume there may be a compliment in there somewhere.

There is - you know I admire your work John.

 

[johnymd]

Some more parts arrived.

Might as well do the cam belt and water pump while it’s easy to get to. I’ve removed the crank pulley to fit a 36-2 trigger wheel so half way there. New exhaust manifold and downpipe were just over £60 and will need a little modifying to miss the steering and chassis. Fuel pot and pump setup is an easy all in one unit to allow you to go injection plus some nylon fuel hose and fittings (rubber hose on this one). I’m going to try out a small cheap agm battery to see how it holds up. I’ve had to go for the smaller alternator I could find to fit in the tiny gap between engine and chassis rail. There’s a real shortage of room in this engine bay.

 

[SeanDezart]

Good info Ian.

Have you a plan to replace the Mazda name under the bonnet ? May have missed this but is the MX engine 1.6 or 1.8 ?

IMO, as the 240Z should always have had an option to upgrade to an L28 and triples before injection so the Roadster might have been expected to have been offered with a DOHC - great project.

 

[johnymd]

The engine is the later 1.8vvt engine from a 2003 car. These are less desirable a not a straight swap into the early cars but I wanted to make use of the extra torque of the vvt and these engines are cheap. I paid £225 for the complete engine and box which is about the going rate. I expect to get around 170hp and good low end torque from the standard engine which should make it a fun reliable and economical car to thrash around on sunny days. My budget on this one will be tight and luckily all the mx5 bits are really cheap. A mates rates on the full race spec wiring harness and life racing ecu were still expensive so I’m paying for it with labour restoring his cortina suspension. Although I’d sooner spend the time on this car it’s an easy job I’m spending my evenings on.

 

[status]

Are you going to Le Mans in it Jon
Should get round and have a butchers at Ian’s car still lots to do but worth it,I bet IAN was like a dog with two cocks when he heard you had one of these he only lives up the road from me so if you do pay him a visit I’ll pop over with that spoiler

 

[Rob Gaskin]

John, one day I want you to install one of these engines in an RX8. I'm sure there must be hundreds of RX8s 'parked up' or being scrapped due to engine issues.