ShrigleytubeTV ep27 visit from Simon Benoy, 1120cc valve clearance plot, 998 refresh, machine clean

[@CraigyD123]

Great vid, really good to see the cut out head and a great explanation of valve overlap👍🏻

[@thehillmanator]

Thanks pal hope your all well, see you soon

[@paulrunell7821]

another great video

[@thefamousfive6271]

as always Andy, a brilliant video

[@Jamesibbotson875]

Good to see Mr Benoy on the channel, he was kind enough to let me and Dad spanner for him for years in the HSCC, brilliant childhood at the weekends at various race circuits up and down the country🏁🏁

[@thehillmanator]

sowing the seeds in the next generation of racers !

[@petercunningham3469]

Good stuff👍

[@havenview]

That cut open head demo is a (pun intended) stroke of genius Andy. You can clearly see 24:53 the valve accelerating towards the top of the piston which is hardly moving People tend to think that the crank and the cam being connected equates to equal movement but the different profiles of the crank and the cam along with the rod length mean they are very much different especially at TDC between the exhaust and inlet strokes. Really nice engineery video

[@thehillmanator]

Thanks Steve, yes the whole thing fascinates me and how rod ratio and other factors effect the dynamics, cheers andy

[@martinhacche1329]

A conversion plate to an alternative box would be good, it would have to be quite small though as space is limited 👍👍

[@thehillmanator]

imp box well up for the job i have never had one fail

[@paulwhiteman3625]

Brilliant as always, Andy!

[@thehillmanator]

thank you

[@stevecmason-rs6vf]

Yet again, another great video. For the age of design and manufacture, the Imp engine still looks special. The compact design and various tuning that can be done is just brilliant. Keep the info coming. Thanks

[@thehillmanator]

Thanks yes 115hp in a 55kg package take some beating

[@oliabid-price4517]

About time you got the place a bit tidier Andy, otherwise you'll start to lose stuff! All the best - Oli in Norwich.

[@thehillmanator]

ha ha interesting thing is when its tidy i cant find anything !

[@antmassey6135]

Brilliant video Andy. Very informative for a novice such as me. Looking forward to the next one. 73's Ant.

[@thehillmanator]

Hi Ant, glad your enjoying the channel, you will be an expert in no time !!!

[@timbo19751975]

Love the Blanket Blank style mic on a stick!

[@thehillmanator]

I love it! its a telescopic ariel with a magnet on the end

[@scottclements1040]

loving the repurposing of the piston on Simon's cam cover, keep up the good work.

[@thehillmanator]

ha ha i like that too, perfect size

[@hermionegranger9251]

Your best yet. Great content Andy. Can’t wait to see what that M14 cam does on the Dino and the 1120 too

[@thehillmanator]

Thank you, m14 was great !!

[@PJIMP1040]

Absolutely brilliant this week Andy. Neil’s engine is looking brilliant and I’m truly gutted that I can’t come over with him to see it on the dyno (The other Chuckle Brother😂)

[@thehillmanator]

Thank you Paul, hope the op goes well cheers andy

[@neilmchardy9061]

In sporting car trials the imp was the go to engine for quite a long time, especially the sunbeam 1040 variants, there were a few 1120’s but there was was a guy had an S.R.B. Car with a 1300cc engine it was very long stroke but eventually died when it broke its one off crankshaft next to the flywheel. I believe he replaced it with a triumph acclaim engine and the whereabouts of the big engine is to me unknown.

[@thehillmanator]

hi oh wow yes i have bought a large trials engine in the past, the crank had been built up using spray metal before been offset ground, didnt appeal to be honest.

[@iancooper5615]

Another great and very informative video mate, top stuff and i too will help clean your workshop if curry is the payment 🤣🤣

[@thehillmanator]

Thanks Ian, he worked hard for that curry bless him i think he just wanted to be on shrigleytube !

[@erichlausch9886]

👍👍👍👍👍

[@whitemonkey7932]

Standoff is where the engine.speed hits a harmonic whereby the scavenging effect of the exhaust and the ram air self supercharging effect is at maximum and the charge air has nowhere to go but create a shockwave and appears to float at the carb inlet

[@thehillmanator]

Thanks, makes perfect sense

[@martinhacche1329]

I’m sorry, I meant front engine rwd layout

[@scottclements1040]

The 1.0 Talbot Sunbeam used the 930 version of the Imp engine, set up was front engine rwd with a normal gearbox, unfortunately not many of the gearboxes around.

[@69waveydavey]

You forgot the piston return spring.

[@thehillmanator]

damm!i will pop it down the plug hole

[@johnpayne3953]

When you shim the gudgen pins wouldn’t it be better to heat the piston?

[@martinhacche1329]

I’ve been following your build program for a while now and wonder if there is a rear drive gearbox application for the imp engine?

[@thehillmanator]

hi yes the imp has a fantastic tranzaxle as standard

[@k.kristianjonsson1537]

Are the Farndon crank and these special con-rods the solution for the Imp engine? Is it still wise to keep under 9000 rpm?

[@thehillmanator]

there are many factors that make these engines work, keeping under 8500 is the main factor

[@Grahame59]

Just curious where the oil filler is on Simon's engine?

[@christophercullen1236]

That's a start to get your work shop up to professional standard ! Hate to see the inside your motors . Kit from down under

[@thehillmanator]

speechless

[@christophercullen1236]

​@thehillmanator are you a customer and get your engines built in these conditions .( check out Barnum engines and Grace engines for their upgrades on working conditions))

[@nmc356]

On the 64/34, is that accurate? The gauge looked like it was on an angle?

[@thehillmanator]

yes your right not 100 percent accurate, could do with the follower been a bigger diameter!

[@sidecarbod1441]

Andy, I really like watching your videos but you haven't got things quite right when it comes to the valve to piston clearance. If the inlet valve does not hit the piston when you are turning the engine over by hand it won't hit even at 8k RPM. The reason is that the valve will always follow the cam profile exactly as it is lifting off its seat. the pistons will always follow the action of the crank, they have no choice. The exhaust valve is a different kettle of fish, as the piston is coming up the bore the exhaust valve is closing, now if the revs are high enough and/or the valve spring is weak there is a chance that the closing valve will not be following the cam profile, in other words the valve is not 'keeping up' with the cam, or to put it another way it is floating. This means that there is a chance that the valve is hanging down further than it should be and could therefore could be hit by the piston. Valves will only float either as the cam is going 'over the nose' or on the receding part of the cam profile, they won't float on the lifting part of the profile. There is one other consideration that you need to take into account if the engine runs hydraulic lifters with preload like the RV8 but I won't bore you with that. Finally the tightest valve to piston clearances are not at TDC, the exhaust valve is usually closest to the piston around 10 degrees BTDC, the inlet around 10 degrees ATDC. Sorry for being a fussy bugger over all of this but the "devil is in the detail!" I look forward to your vids, keep up the good work, oh, I'm interested in what you are going to do to the valve train of the RV8 in order to get that to hold up to the revs that you mentioned in the other vid!

[@thehillmanator]

Thanks glad you enjoy the videos, regards your statement about contact at cranking and at 8k surely the piston goes 20 thou higher when it gets to the top of the bore on exhaust stroke ? or we could run the piston right up to the head like a 2 stroke engine ? i run 20 thou squish at tdc providing the engine runs to max of 8500 rpm then i see minimum witness mark where no carbon can build, any higher on rpm and start to see imprint on the piston from the squish areas. on the imp i am pretty convinced that because of the good design valve train and lack of reciprocating mass the valve follows the cam profile very well, i can imagine on an engine like a rover v8 this is much harder to achieve at speed due to having to control the weight of the follower, push rod, rocker and valve/cap etc the rover i ran to 8250 rpm had nice heads with 7mm ford x flow valves, volvo p1800 rockers bespoke hollow pushrods and modified std followers with the insides removed and a cup machined into the bottom of the follower for the push rod to sit. i have a video of it on an old phone i will attempt to add it at some point for you. cheers andy

[@sidecarbod1441]

@@thehillmanator Hi Andy, yeah I'll give you that one....the fact that at 8k you will get some rod stretch/crank whip etc! I guess what I was trying to explain is that the piston movement is controlled by the crank, it does not rely on springs to make sure it follows the path that is it supposed to follow. The valves on the other hand can, if things are not right end up being in places that they are not supposed to be in. (Ducati get around the issue nicely!) 2 strokes are actually something I'm very interested in, we don't run the piston right up to the squish band but it does get close, depending on the size of the engine it will be around 1mm, if you run the piston too close the velocity of the fresh charge being ejected from the squish gap gets too high, for some reason or other if the velocity goes too high it actually promotes detonation, and detonation is the thing that kills many a 2 smoke engine! A nice combustion chamber and squish band is one area where a 2 stroke possibly does better than a 4 stroke as there are no valves or funny lumps on the piston crown which can mess up the shape. Volvo rockers in an RV8 is a good way of getting some adjustment into the valve train, I tend to use adjustable pushrods but its swings and roundabouts really, converting the lifters to sold is a good move too! Shortening the rocker shaft pedestals is a good mod in order to improve the valve train geometry, its pretty bad on a stock engine and it only gets worse when you stick a decent cam in the engine. Also the rocker shafts can also break at either end where the two outer pedestal bolt holes are, you can buy pedestals with an 'out-rigger' support which helps to stop the shafts from breaking. If you can find the older machined-from-solid valve spring retainers that's also a good move, the later ones are made from sintered metal, they are not as strong, they can break.