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

This very much rang true with me. I've tried tweaking a few things and made things worse, so currently worked a way to put up with the foibles so I can enjoy the car. I really need to get stuck into educating myself

You've created a lovely thing!

Yes that is an excellent noise

Yep, I had an early 1300 in light metallic blue, with highlights in black mastic and brown. What a rotten little thing it was. And slow. And prone to refusal to proceed…. or suddenly facing the wrong way….. this last may have been mainly indicative of driver enthusiasm exceeding talent.

There’s no doubt that mine was a terrible example. Never send your mates to “look it over” just because you’ve had to work the weekend is the moral of that story. I’ll not spam up Alex’s thread with the extended tales of woe relating to it.

Suffice to say that I’m able to appreciate them (after 30 odd years of healing!) and I did at least make a paper profit on it (if my labour was free). Also sold the most easily of any car I’ve sold… though I did live a couple of weeks in fear of the disgruntled purchaser bring it back 😀

Over a month has passed since the last update. That went quick!

I've been busy on other jobs so the Imp had to get time where I could. The cooling system was what I wanted to sort out. I had emailed Davies Craig about their electric water pump controller. I explained the issue in detail and the friendly tech fella there ended up calling me a few days later. We chatted for 45mins and ran through the system. He'd actually taken the time to read the full build thread which he said he'd really enjoyed. This also meant he was well informed about my setup.

From the conversation I learned that I could have a more effective bleed system setup which will help not only filling the system up from dry but also possibly help the warm up. If it didn't warm up effectively enough after changing that then I could add a traditional wax type thermostat in.

I had already gone down the path of starting to make a remote thermostat housing before the phone call anyway so I continued with that first. We had popped to the wreckers and got a thermostat and its cover from a Nissan k11 (of course..).

I machined up a flange to take that and welded it onto a tube. Then stepped the tube down in size, added extra alloy I could drill and tap to suit the 3 temp sensors. In the end the whole thing was made from about 7 bits of alloy. Its not pretty but it fits in the same location as my original sensor pipe.







You can see the added bleed stub sticking out. This bleeds off air to the new expansion tank I was going to make. I have added the same size take off onto my original sensor pipe which I'll be using first - just in case I might not end up needing a thermostat.

Originally the sensor pipe had a larger feed pipe taking fluid from the expansion tank - which I was informed was the wrong location because the sensor pipe is on the pressure side of the pump, coming off the engine. Not the suction side that it should be feeding into.

Silly me.

So I now had to add a feed point somewhere into the system before the pump. Luckily there was just enough room to do so on the pipe just before the pump. I removed the pipe from the car and added this feed here...



I also removed the main front to back pipes that run under the floor. I was happy/relieved that they come out ok without having to take out the fuel tank. I wanted to drain the complete system of the old water/dirty coolant mix but these two pipes can't be drained properly and they hold quite a lot of fluid.

So I fixed this issue. Machined up some drain points and welded them at the lowest point..







Super easy to drain the lot out now without having to even touch a hose clip.

Now onto building a new expansion tank. I have been planning to do this for some time. The old one that came with the race car is steel, heavy, ugly and rusty. It also sits in the wrong spot and upsets my engine bay Feng Shui. It just had to go. This is also where some time got lost....

I started by machining up a filler neck to accept the smaller type of radiator cap.





Then some simple cad work...



Welded bits..



Cut, bent, folded, welded, machined and out popped this...





Wire brushed it...



Painted it in epoxy paint (and the thermostat housing too)



Bolted it in place...



Then chopped it up because I didn't like it...



Yep. Bit of time down the drain that. But I just wasn't happy with it. It was still too obvious, too sticky outy and upsetting the generally symmetrical engine bay. It was also going to make my planned bulkhead cover more awkward to make and fit neatly. So back to the drawing board. I cut out the filler neck, machined it clean and started over. No pictures of it being built because I just cracked on and got it done. Finished result though..





You'll see how it fits soon.

Next job was to see if I could quieten down the exhaust boom. Those exhaust valves didn't seem to make much difference in sound and it was more than loud enough anyway. So they could get lost. I took the muffler off, such an easy quick job. Took it apart...



Removed the exhaust valves and made some extra baffles to hopefully knock a bit of sound off. V shaped 'ceilings' in the first expansion chambers...



and extra baffles on the outlet chambers...



I also removed the crossover hole between the two halves. Simply not needed on a flat six and I suspect it was stopping the distinctive flat six sound at idle.

Bolted it all back together and got stuck into the next fun job.

Not an essential job at all. But one I wanted to do. I have never liked the ugly, non symmetrical covered up hole where the Datsun cylinder head used to pop up through the parcel shelf. I've wanted to hide it behind something nice. So I got a sheet of alloy from our rack and cut out a cover. Gave it a curve in the folder...



Had to recess it in the very centre right where the Plenum/spaceship resides. Not much luckily.

Cut some strips of 4mm alloy...



Gave them a 'brushed' look with my poor mans linisher...



I had been ringing around all the various upholsterers about my district and no one had any black leather in stock plus the prices they quoted were absurd. I had bought some black vinyl instead but wasn't really happy with the idea of something so flammable being above the engine. Popping into Tasman canvas on our way home from town was just an idea at the very end of the day because I thought maybe a canvas could work. But they had some leather left over from a job and were happy to help out with some offcuts.

Leather carefully glued in place...



Then the alloy strips were carefully bolted in place. Before fitting the leather Hannah and I had deliberated over the positioning and spacing of these for some time. The idea is that I can remove them at a later date, cut them short so the middle has a gap in which I can fit a badge/logo of some sort. This will then mean there's six strips, 3 each side, much like a flat six.

Deciding on what to put in the centre is now the hard part.

So some pics of it all in place, along with the new expansion tank tucked away to the side...(the little bolts will be changed to dome heads when I next get some from the city)







I'm pretty happy with that. I might well change it out later on but for now its hiding the ugliness behind. The new tank is a huge improvement in looks and its tucked away neatly. The new bleed system is a massive improvement too. I filled the whole system up so quickly (9 litres in total ) and the air bled out really quickly this time.

We started the car up today. New exhaust is quieter but still a bit boomy at certain revs. Not a concern right now as its not a daily. Just a fun toy.

The cooling system heated up much quicker (A very cold clear 10 degree mid morning at the time of testing today)

(EFI tuning talk time. Carb folk look away) I'm now going to spend some time really trying to fine tune the idle. Its idling happily at a touch over 700 rpm but I think that's a little low. The hesitancy just off idle when for example you squeeze the throttle to pull away needs to be tuned out. I think I'll get it sorted on the VE table alone. Its not an acceleration enrichment issue. I want to get this area sorted so anyone can jump in and drive it about town slowly without any stumbling or hunting. Its still on open loop warm up idle control which I want to have dialled perfectly before I look at maybe going to closed loop.

This is pretty much what I have been doing. Just takes time to get right eh.

As for hot start issues where on my previous update I had mentioned how I'd increased my crank to run taper time out from about 6 or 7 secs to 12 seconds to avoid it bogging down and stalling after starting.

I now realise that it's probably just a after start enrichment issue so I need to re-address that too.

So a few things to 'play' with and I'll try my best to tick them off one at a time, make notes, learn and improve the whole start and idle as I go.

Good idea on J pipes but yes- packaging. Even if I could possibly fit them (which I don't think I can) I'd not be happy with the look.

I might just put some ear protectors in the footwell for sensitive ears

Please feel free to nick my lid stay design. You're the second person to mention that this week. A fella on a porsche forum (that a certain teaboy has frequented..) likes it too. Its actually a stainless shaft and plastic knob from a coffee plunger, bent to suit.

Tea boy owns a Porsche ? Who knew.

Horribly smart little car, a pleasure to watch progress, thanks for bringing us along.

James

Happy birthday mine was only 4 days ago, but I also have a "few" years on you cake and beer was consumed