Hillman imp + Honda flat 6. Musical engine swap game..

[biturbo228]

Great work!

As you say I'm not sure the 5mm engine mounts were quite necessary. For reference, my 278kg Jaguar AJ6 had engine mounts 3mm thick. A nice triangulated design sure, but still not all that beefy.

Though I doubt there's anything noticeable to lose in going for thicker steel...

[yoeddynz]

Yeah I figure its best to stay on the 'if not sure then over build' side of the fence with the mounts. Only downside was a little extra time and a few grams of extra weight.

So many little jobs that add up to suck time. But its a fun time to be at and there's no point in rushing it.

The rear seat base was next up because I needed to work out where I could run the engine loom through. I tried the base in place, got an idea of how its steel rod framework needed to be adjusted and set to it.



As you might spot in the above pic I also gave myself a decent cut from something sharp in there.

Seat base now fits in neatly although it wont be a luxurious softly sprung seat for a middle passenger when 5 up. Highly unlikely scenario that is an Imp though.

Megasquirt and associated fuses/relays etc are tucked away under the seat.



I made some mounts for the exhaust box..



Welded the mounts in place and I was then able to tack, then weld the secondaries to their flanges.





I painted the crossmember after having added some handbrake cable guides. Then it and the rear suspension was all bolted up in place. The new driveshafts fitted and hubs pulled on, wheels bolted up and it was rolling again. So it got rolled out the back to join green imp so I could use the hoist to do a customers van job.



As soon as the van was fixed and out of the shop I put Impy back up on the hoist. I then worked out the final section of pipework for the clutch's concentric slave cylinder (CSC). I wanted the bleed nipple to be easier to access and not have any spillage running down into the bellhousing. I made some pipework and fittings to suit.



Bench was covered in brake fitting stuff and I pieced together a system.



I made one setup, tested the clutch and while it worked fine I wasn't happy with the pipes sticking up in the way so I changed a it again leading to the final iteration..



The csc itself was a unit I'd scored from a Ford Mundano engine and gearbox I had well over 6 years ago. Intended to fit the duratec into my Viva wagon. Sold the engine and kept the release bearing just because I thought it might be handy. So six years I've had it laying about and before that it was residing in a wreckers yard. It must surely be a bit cruddy inside?

They are not designed to be serviceable but they are also stupidly priced here in NZ - like triple what they cost in the UK. So I decided it was going to be serviceable and I took it apart. Sure enough it had some mild corrosion marks on luckily what is a stainless guide tube but otherwise actually pretty good.





It cleaned up well in the lathe..



Its a very nicely made thing and quite simple but has to be mounted correctly. This guide tube seals on the mounting plate with a thin square section seal.





I made a new bigger mount to support the base because the original machined support I'd made wasn't broad enough. I was then able to add two more bolts to sandwich the lot together so that square seal remains squished evenly at all times, as it would in a OEM situation.



We trial fitted it all with the new base plate and pipework. I was not sure whether my stock Imp 5/8" bore master cylinder was going to move enough fluid to get the release bearing travel I needed and I was prepared that I might have had to fit a 3/4" M/C. However it all seems fine with a light pedal and the bite point is about midway. Very smooth motion too!

While this lot was being done Hannah finished prepping the rear valance for paint. Luckily the weather here in Tasman, NZ has been just amazing for what is now officially winter here. 18-19 degrees recently and generally clear skies (in fact its a bit too dry) So on a nice warm morning I set up the paint frame outside and sprayed some blue about..



I did my best not to paint the cat blue..



It turned out fine..



Another little fun job was cleaning up the gearstick shaft in the lathe..



...and discovering that universal steering rack boots make for neat gearstick boots...



I'd bought some muffler packing sheet and then played with scissors...



I then painted it with stove paint and sat it on the burner to help it harden. It looks much better in black. I've used silicone to seal the lid. Ran some beads, let them set for a couple of hours till at the point where it squishes flat without smearing. Stainless bolts carefully pulled up evenly. Seems all good but only time will tell on how the seal lasts. Like a few things on this build its a bit experimental.

Gaskets for the inlets and tailpipes are copper. I have quite a bit of decent thick walled copper pipe from the Imp racecar cooling system. Chopped some bits, flattened out, heated and quenched with the oxycet and now nice and soft.





Exhaust all mounted and engine now ready to go in for the final time (he says..)



I just had to get a few more pics of this stage because its a point I've been looking forward to





Positioning the power plant under the car..





Yep. Getting very close now!!!

[legend]

so so good, what an outcome

[mrbounce]

Epic.

[blackpopracing]

That looks so cool.

[jjp666]

Not sure if that belongs in the car or an art gallery.

[eurogranada]

Magnificent!!

And the colors match so well!

[biturbo228]

Oh man looking really close! Also looking like it'll be dead easy to remove if you ever need to in the future. Two driveshafts, the gear linkage, couple of coolant and fuel pipes and some mounts! There's all the wiring too, but if you have a big plug and a separate engine loom then that'd be straightforward too.

[jamesd1972]

That's automotive filth.
James

[yoeddynz]

Jun 3, 2024 12:24:10 GMT biturbo228 said:

There's all the wiring too, but if you have a big plug and a separate engine loom then that'd be straightforward too.

Yep there's two plugs. A 26 pin item for all of the engine management and a 6 pin one for the oem things that are also on the datsun engine such as oil pressure, temp, alternator excite/lamp etc. So when the datsun goes back in it will simply plug into that smaller plug (for the next 'mot test'.. so I can get a pretty sticker for the windscreen and then refit the Honda - a process that won't be needed once the swap is certified)

There's 4 other wires that I couldn't let in. The water pump feed and it's own temp sensor (which I can't cut or extend as it will change the resistance the controller sees) luckily they both have plugs anyway so they can stay on the engine.

[Clamity]

Jun 2, 2024 9:08:19 GMT yoeddynz said:

Positioning the power plant under the car..

Ooh you big tease! I bet you've already got videos of this razzing about the mountain roads and you're just making us all wait on the edge of our seats...

[yoeddynz]

Oh I wish.

But very soon!

[v8]

That is EPIC mate

[yoeddynz]

I will try to keep updates coming along a bit closer now as I tick off many of those little jobs.

The useful alloy scooter handle bar thing I'd picked up at the dump ages ago is getting shorter and shorter. It happens to be 32mm OD and ideal for many jobs such as extending the sensor housing so I could add a 16mm tee for my header tank..



Another bunch of little bits to do was the air filter mount and associated points to feed the IACV, the catch can and a place for the air temp sensor. I made an alloy mount which bolts to the firewall in about the only place left that would fit it. It connects to the throttle body by flexible ducting.

The Goldwing engine just has a simple breather system. The crankcase is under a constant light vacuum and any blowby fumes are drawn straight into the air box before the carbs. I decided ages ago I would just replicate it. I machined up a Ventura...



Oh. Hang on. That's not right.

I mean Venturi...



with some other bits..



Looks like this inside...



I made a little stainless catch can with shelves and stainless scrubbers - for scrubbing out any oil mist. It has a drain plug which is easy to get to.





Painted it black so it hides better (not exactly a pretty thing)

It, along with the filter and filter mount plus associated tubing all resides at the back of the engine bay, luckily out of sight because its all a bit messy. I tried my best without getting too carried away. Its tight in there!..



The two main plugs plus the wideband plug are tucked up nearby..



Also nicked the oil pressure sensor from the Datsun engine and fitted it in place...



Lifted the big folder into place and bent some steel sheet ...



...to cover the hole that normally has a Datsun cylinder head poking through it...



Used rivnuts so now it simply bolts down in place.



I'll glue foam on top so it'll match the rest of the parcel shelf. I'll eventually cover that with an easily removable carpet mat. Its super handy having this access hatch. As for the underside - that will get painted blue for now and I'll be looking into some sort of cover that simply screws in place, possibly with a covering like vinyl or something. Maybe use pop studs to hold it in place. Just something neat and uniform that will hide the hole.I'm still thinking on this one.

While I had the folder out I cut out a bit of 0.7mm stainless sheet, curved the edges and hey presto - a heat shield for the exhaust silencer...



That's about where I'm at as of today. I've just started looking into fitting the fuel tank but I need to get some more hose. We also wheeled the green imp into the shed and this evening started making it smaller. Eventually it'll be so small it'll fit into the van and can go to the scrap steel man, less the roof and some tricky shaped sections I'm keeping just in case of whoopsies in the future. It's also handy to have another spare set of suspension arm, hubs and axles etc.

This shell really is too rotten to rescue considering the sensible values imps still seem to be at so I didn't cry too much at first cut. Bye bye little green Imp. You served me well and will not be forgotten...

[cortina64]

Looking forward to seeing your next update Alex, watched your video on your YouTube channel and the sound was amazing! This would have to be one of my all time favourite builds. Your skills and vision is amazing, hats off to you and Hannah for an awesome build.

[yoeddynz]

Hey man- I've just seen your comment on my youtube vid. Thanks so much. Here's the update...

Chopping up the Imp shell took longer than expected. I'm pleasantly surprised at how solid they are for what is just a budget small car. It was also even rustier than expected and I'm glad I was not tempted to try and make something of it.



I had to get this shot...



...and this shot.



All chopped up...



I rescued these bits. I have no idea where I'll stash them. Maybe hang the nose cone from high up on the workshop wall, led lights fitted into the headlamps. I've now got a full spare set of suspension arms too. These could come in handy as bench top jigs if I look into mounting disc brakes on the back etc.



We took the remains to the scrap man the following day and he gave us $78 in return. I had paid $200 for the complete Imp so it now owes me only $122.

Or I prefer to look back at the pies, cakes and coffee we both had in town after seeing Mr scrappy.

Back to the Impy project. I now really only had a bit of wiring to do plus some other little jobs. Wiring first. A bit of work in the 'frunk' to clean up the fuel pump wire routing..



Drained the last of the coolant out while I was there.. glad for the handy drain plug I had added when building the radiator in.



Work where the car needed to be on the hoist was over with but before I lowered the car onto its wheels I grabbed these shots which I really like..





Onto its wheels and rolled away for the first time since fitting the flat six. Wow. Pretty neat occasion in itself. Happy to see it still sat at the same height. Looking forward to weighing it in the future and seeing how much lard/muscle/festive season insulation its put on. I was now able to climb in and out of the doors easily and sort out the final wiring.



Stuff to be done was running the power and ignition wires to the ecu, water pump wires and some sensor wires forward then make it look all serviceable and neat enough. I had to extend the water pump temp sensor wire so the controller could be mounted in a sensible place. Take note of this last bit as I'll be coming back to it...



With the wiring now sorted I could move onto finishing of some other loose ends so to speak. But first I had to start the engine up in the car and check it worked. Which it did after I swapped the two fuel lines in the frunk about so the feed did actually feed the correct line etc - only discovered when I was under the car with a container to clear the lines out of any debris and it came out the other pipe. Whoops.

So yeah. The engine just started up with no fuss on first turn of the key. Simples. Sounded great. The was no water in the system so I just ran it for 30 seconds, gave it a rev and let out a little giggle.

I then painted the parcel shelf cover thing that I'd made in the last update...



While that was drying I made a little lever for the exhaust valves. I started with an old pulley that I'd originally made for my V6 Viva..





Ran a long length of bicycle brake cable through from the engine bay into the interior via the routing that one of the original Imp heater hoses took. Connected the dots with a tandem brake cable inner..



Out with the rivnut tool and put a couple into the inner sill.



Lever mounted...



Sound levels turned up to 11, small kids scarper, nuns faint and dogs howl in the distance* when lever is turned as such.



*Hopefully.

Next up was filling the cooling system with water.

Not coolant.

I've learned from that mistake and I'm sure I'll be having to remedy some sort of issue which might involve emptying it out again. Turned the electric pump controller on and noticed it telling me the water was a balmy 54 degrees. It definitely wasn't. Its winter here (apparently) and the water was 15 degrees according to my volt meter temp probe. That bloody sensor wire! When I lengthened it by about 800mm I used 12/0.15mm gauge wire. The original sensor wires were 17/0.15. I didn't think 5 strands @ 0.15mm were going to make enough difference to change the reading but how I was wrong.

So this was where I was working early evening yesterday...



I rummaged through my extensive supply of cables, picked out a few that might be ideal and started with some beefier speaker cable that had many more strands. I didn't count them as tiny. I just connected it up and tried it out. Bang on! Both meters read exactly the same. I tidied it all up and we started the engine. Ran it up to temp which took ages because by now it was only about 11 degrees. No leaks and the pump seemed to bleed of air easily. Hannah took a vid of me giving it a cheeky rev. Such fun. You'll see that in the next vid. Interestingly and annoying is that the exhaust valves don't seem to do anything to the engine note at idle. Maybe they will make a difference when asking more of the exhaust?

It was by then too late to go out for a hoon. I still had to fit the belts, all of the seats, the nice blue parcel shelf engine hole cover and also the actual engine bay lid. So I spent the evening finishing these tasks off. I'd love to have driven it because it was a clear, albeit cool, day. Lots of heavy rain expected the following few days. Oh well. It was great to see the interior back in. Although the recaros don't match the interior colours I just love seeing them. I like this pic. Old and new. 'West German' seats, old imp interior, sneaky megasquirt and usb cable.



So this morning it was finally time for the big occasion. There were so many things to go wrong, not work, be noisy etc. We just popped a tool box in the front, plugged the laptop in and went for a drive...



Wow. It works! The clutch pickup point was spot on, gear change seems fine in a mechanical way. The gearbox was quiet. No whines. The engine was completely out of tune and we couldn't really tune it properly on this short drive. We did about 12km but a combination of the very cold morning and a very efficient cooling system meant the engine wouldn't get above about 80 when on the move so for much of the drive it was still on warmup enrichment. I now realise that I should have upped the temp setting on the pump controller. I think the default is 85 degrees so it pretty much had the pump running full time. I want this engine to be running at 95 degrees C. But hey - great to know the cooling system works well at cooling.

The exhaust is more than loud enough. There's no insulation above the engine cover so that will refine the interior when cruising and how cool it is to pop into a 5th gear!!! Again, due to lack of tune I couldn't really note what the gearing is like. I never really gave it the full welly because my dash rev counter wasn't working (I have a sneaky suspicion I plugged in the wrong signal wire that currently goes no where)

I just drove the car and enjoyed the fact that this moment was finally happening. Hell - it was March 4 years ago that this engine first arrived on a pallet.

The things that were not so good..

The clutch bite point got lower and lower until it was tricky to get into gear. Either failing slave or master cylinder. I suspect (and hope) its the MC.

Its a bit fumy. Granted it was running pretty rich and the rear cover I've made is not sealed properly.

The gear lever knob moves back and forth with the engine/transmission movement. Not annoying and only noticeable if you keep your hand on the knob (chuckle) while accelerating. I had figured it would because its a very slop free mechanical connection. Maybe stiffer engine/box mounts might help but then I could expect to have more noise in the cabin.

The weather was a bit curse word so we went home, had coffee and cake and I looked over the car.

It leaks oil. Typical. It was weeping/dripping from the point between the heads and case sides where the oil drains back into the sump then running back with the airstream and spitting onto the muffler. So there's some of the fumes then. Only happens when the engine is running but its enough to be an issue I want to sort out asap.

The leaks are here. This side where it leaks straight onto the cooling pipe and runs back...



The other side.. Nothing to leak onto but its still getting flicked back by the airstream onto the muffler...



Here's a head gasket.



You can spot the drain hole. Its only pinched up at the bottom by one 6mm bolt. If I knew then what I know now I'd have added a thin smear of threebond sealant on each side of the loop to be sure. Oh well.

The mess it made on the muffler.



So that's where I'm at. We checked the clutch. It works fine on the hoist. Bite point still at halfway?. No obvious leaks or traces of fluid from a leaking slave cylinder. Fluid level was fine. I'll check the m/c tomorrow. We bled the system again just to be sure. Only other thing I could suspect would be a dragging spigot bearing but I cant imagine that being the case. Its a new sealed bearing.

As for the oil leaks. I'm going to try removing the lower water pipe in situ and get enough room to apply marine sikaflex 291 or similar. Its under no pressure so hopefully should seal ok so long as I get it super clean beforehand.

We will test it all again, leaks or no leaks, when the rain stops (rain warning for our district this weekend) but for now I am simply chillin' and relaxin' and celebrating the first drive in a flat six powered imp that sounds pretty glorious.

[glenanderson]

Fabulous. 👍

[remmoc]

Brilliant news

[redratbike]

what an epic moment for you

can’t wait till you can get a tune on it and hear that flat 6 sing!!!

i commented on one of your facebook posts the other day

[ivanhoew]

just brillaint ,well done chap


re clutch , i don't suppose the fluid line could be getting hot could it ?