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Discuss here about Yoeddynz's little Imp project...


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  • 7 months later...
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  • 2 months later...
38 minutes ago, yoeddynz said:

Well then..... so I'm going to now have to remove the terrible Datsun engine after having been informed its crap by some Barry commenting on my 'first drive' youtube vid.  He stated the following....

"Why would you replace the high efficiency Imp engine with a Nissan updated version of the BMC A series engine? Imp engine is 875cc all alloy overhead cam engine with high grade steel bore liners, with crank balanced for 10,000rpm as standard. The A12 is an A series bottom end pushrod OHV engine with improved alloy cylinder head. The Imp engine can be easily tuned to 100 bhp per litre with just work on the head and carburation, as shave it to raise compression, bore out for larger valves and fit high lift cam, plus add twin carbs with Stiletto manifold. I don't believe you can get 100 bhp per litre from the A12 no matter what you do to it"

I'm sure @RUNAMUCK, who's driven my Imp with this engine, or @kyteler would love to have a little chat about just how terrible the A12 is....:lol:

Anyway - my reply was this...


"Torque!, reliability, easily available parts inc so many performance upgrades, bomb proof bottom end, very strong crank as stock, only 15-20 kg heavier. Easy as to get 100bhp per litre! How about about a Tomei built 170bhp 1300 A12 ... https://www.youtube.com/watch?v=nRRHnvUhDbU&t=126s I've owned a stock imp before this and driven fast imps in the UK with the 875/930 engines. This engine, even as completely stock with a tiny Hitachi carb simply blows them away for usability and mid range grunt. It is also MORE economical. My only gripe with this engine is its upright position which has lost me some of the useful parcel shelf. But hey- that will soon be sorted when I finish my flat six swap. Oh boy- that'll upset the Barries! Haters gonna hate.... "
I look forward to seeing his reply.
Bloody barries :rolleyes:

I can't help but agree with you, having owned a standard Imp (first car - prob not the best choice!) and then building a somewhat worked engine (as in mods listed by Barry) for another dirt-track race car, while it was fun we ended up with an engine that was mostly undrivable - nothing below 5K rpm then once on cam you were just going sideways at 9K rpm. What I would have given for a engine with low down torque!

Pic of said weapon.


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Sweet- I never knew you'd had a couple of imps. Yep- to get a load more grunt from 875cc you need to deal with less usable torque and also an engine that is going to be even closer to it limits of reliabilty.

I should have just replied to that barry with the word 'headgasket' :lol:

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8 hours ago, yoeddynz said:

Ha cool. So nippy through all the cars at the start. Then gets hammered by the long legged big cars on the straights.  Cool footage!

Yeah poor guy is one cog short down conrod so just pulls over and lets them pass, then takes it all back under brakes, so cool!

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9 hours ago, flyingbrick said:

This been shared yet? So good 


Yep I've seen that. Its good eh.

Looks like whoever (barry) put it up has made it by filming the doco (probably at some museum) with their phone - that reflection eh. 

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  • 1 month later...

So a fella on another forum has pointed out an issue I had not thought about and has put me in a mild pickle.  I have a couple of solutions, one of which could improve other things at the same time.

Lets see if anyone can guess my error. I'll give you all a clue.

Starter motor.


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21 minutes ago, Nominal said:

You gonna be spinning it backwards?

yep- if I mount the subaru starter in its stock position I'll be turning the motor the wrong way.

Didn't even think about that. Whoops.

However I have a couple of options. Either use a Honda starter from a counter clockwise civic/accord etc. These rotate opposite to most starters. But I need to check the pinion tooth pitch. From what I can see via rock auto pics they are the same tooth count , 9, and look about the same diameter. I am guessing that most Japanese cars share the same pitch teeth on ring gears?

Or I can mount one of my subaru starters from the front, over the engine.  I have just checked and there's loads of room and will be easy to mount. It would also look more symetrical and the subaru starter was going to be pretty close to the parcel shelf if mounted above the box as originally planned.

However if I do this I'll need to turn the ring gear around. Probably add some welds to stop it potentially getting nudged off because the flywheel retaining lip I had machined will now be on the wrong side.

Nothing too drastic or unsurmountable in the grand scheme of this project and I'm lucky someone spotted it at this point!

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Yeah I can do that- but also yeah it has a one way clutch and by the time I find/buy one of those that works the correct way I might as well get a honda starter.

I have my starter motor squirrels out there looking for me and will have an answer soon. If the Honda route doesnt work I have worked out a way to use the scooby item. I'll put up more details in the next update.

For now I have put the starter issues to one side and I'm concentrating on making a small pile of alloy filings on my vice as I play about with chain tensioners etc..

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