School me in the ways of intaking fuel and air...

So I stop just before I put dents in the hood?

Seems a 1000 more rpm isn't that much, and if it's still making power, there's no valve float right? So in theory the valve train is fine at that rpm?

What type of valve train does the mighty justly have? Direct acting or are there rocker arms?
What's the stroke of the engine?
How thick are the rods? Weight of the piston?

I do know that a stock b230 (80mm stroke) Volvo bottom end can sustain 8k rpm for a few seasons once you toss in some stiffer valve springs. I know nothing about the mighty justy.

Robert, thanks for coming in.

Data? Data?

What is this??? Can't we just theorise on some unknown and solve the problem???

Meh... I thought this was a site for bench racing...

Okay best I can do at this time, is:

Single overhead cam… rockers, don’t have one to with me to measure right now.

Valve springs
length 45.5 mm
Diam 27.5mm
Wire diam 4mm

Cam
Intake
Valve Opening = -2.4 'BTDC
Lobe Center = 108.2 'ATDC
Valve Closure = 26.4 'ABDC
Duration = 204 Crank Deg
Max Cam Lift = .20673 IN.
Net Valvelift = .3101 IN.
Lobe Area = 16.34 IN. *Deg

Exhaust
Valve Opening = 29.3 'BBDC
Lobe Center = 109.4 'BTDC
Valve Closure = -2.4 'ATDC
Duration = 206.8 Crank Deg
Max Cam Lift = .21142 IN.
Net Valvelift = .31713 IN.
Lobe Area = 17.35 IN. *Deg



Bore x Stroke: 78 mm x 83 mm

Piston 234 g
Wrist pin 83 g
Rod 474 g
Rod, pin, piston 791 g
Rod centers = 13cm

I remember years ago JVL looking at a rod and commenting on how beefy it was for "such a pissy little motor"

Compression 10.5:1



Edited 1 time(s). Last edit at 02/05/2017 10:16PM by Mad Matt F.

I forgot how beefy those engines were. We rebuild a few at my dads machine shop and we were really surprised at the size of the rods and crank in them.

So Mean Piston Speed is the deciding factor on RPMs if you're not worried about the rod and piston parting ways. As a general rule of thumb 20m/s-22m/s works with stock (thick) rings, cast pistons, and good oil.
The b230 volvo in the rally car has an 80mm stroke, and HEAVY cast pistons with decent rods. That engine has sustained 8k rpm for minutes at a time, and lived over 6k rpm for most of 25 rally races.
The MPS was 16m/s-21.3m/s for 6k-8k rpm.
If the valves aren't floating and you're still making power, there's no need to be worried in that range.

For the Mighty Justy: 16m/s is 5780rpm and 22m/s is 7950rpm... as a reference.

Also, you can still make power when floating the valves, if done properly. Read up on valve lofting, it's pretty cool!

Sweet!

Thanks Robert.

Pedal'er down!

Ok....

Why always weird stuff last minute???

Rally sprint this Saturday, should be fun.

Justy was running AWESOME... tinkering with a few things, suddenly today... NO SPARK. None.

None at the coil, none at the plugs.

Pick up coil (not hall effect) in the disty, not other electronics in the disty. Some supposed "Ignition module" under the dash - that I assume is the culprit- which will be NLA... 1988...

I tested the pick-up coil, about 1000 ohmns... and it gives a voltage signal when I turn it over, so I suppose it's good.

I wasn't really mucking with wires... so not sure what happened, but went from start to no start just like that. Not much time for diagnostics and ordering parts at this point...

3 cylinders... any thoughts on what I get for a quick, fast aftermarket ignitor thingy that will take my pick up signal and make my coil fire at the right interval? I mean I could make Jeff tap wires together really fast???

Someone tipped me off to mid early 80s Chrysler modules... 5 wires, 2 coil wire, looks to pick up coil not hall effect... sound good?

Dance pixies dance!!!

Engine by Subaru, carburetion by Mikuni, oiling by Chevy, and now ignition by Chrysler.

The Frankenbitch runs!

I am amazed that you got that all working in about a day!
Right on!

What's the difference in ignition curves between the two?
New rpm redline as well?



Edited 1 time(s). Last edit at 08/21/2019 07:45PM by culberro.

Well... we're getting there.

The Justy f'n rips. First time on stage since 2014, new co-driver, and me wanting to only "shake down", we were above mid pack (20 sec back on 3.5 min stage) and there was lot's more to go.

Sir RC the III, ignition curves??? redline??? I lost the tach and couldn't get it working in time with the new module... by ear man... as for curves... who knows... it's just explosions once in a while, sometimes they hit the right moment.

We had 4 good stages, but somewhere along the line my homebrewery oil system was loosing oil. At service we were down 5 litres!!! (the stock sump is 2.8, my dry sump reservoir holds 6.5, but I usually just run 6 to let the top swirl... (de-aerate). I topped it up, er filled it... but the damage was done, a slight rod knock AGAIN... but I will blame this on hot oil. I broke the end off the oil temp gauge Friday refitting the oil pressure bypass block, that might have been a good indicator, but from the sound, I just need to throw some bearings in and it should be good to go again. Now to find the leak...

It is so fun to rip that little car... it makes great sounds, and is just a hoot!

My Nephew stepped up last minute to jump in the silly seat... he posted the phone zip-tied to the cage vid of the first 2 stages, we forgot to turn it back on for stage 3,4. and Stage 5 I noticed the rod knock and backed off.







Edited 1 time(s). Last edit at 08/28/2019 06:58PM by Mad Matt F.

That Justy really looks fun to drive!

Where was that?

---

Ask for work.
If they don't give you work, ask for bread.
If they do not give you work or bread, then take bread.

- Emma Goldman

Vincent,

Part of the Ontario Rally Sprint Championship.

Loom Lake Rd. near Catchacoma Ontario

https://www.facebook.com/groups/1010398825799223/

Cheers.

Hello all!

Hope everyone is doing as well as can be expected in this fACKed up time... FACK

Anyway, The Justy "kinda" works... and as long as the crazy homemade oiling system holds to together, rods seem to mostly stay inside the block! What a concept. My home shop tooling is always getting better, and I'm looking to eliminate the cobbled together Melling 55 castings, and use the internals in a BESPOKE ( ha I used bespoke) dry sump pump housing I hog out of some cheap aluminium beer can ingot from the forge (no... I will buy a block, er maybe), adn then make my pressure relief valve internal of that. I might even double up the scavenge pumps to 2 high volume out, one standard in.

Anyway, there's still a bit of "tuning to do" but to be honest, I'm kinda happy with the estimated 100 hp... I mean it goes like relative hell, and makes a ton of cool noises. I will never stand on the podium at Pines, so who the F cares...

I have some shit homebrew suspension, and I'm planning a bit of an upgrade... But I can help but think of the super Justy noted below and I keep telling my junkyard dog self, that it would do no good to push the wheels out, add some fender flares... but damn that looks like a little Intergrale!

So here's the chance for 6 beers in shop talk, keyboard warrior bullshit time! Tune up your best bullshit and tell me why a car with a 90 inch stock wheel base and 60 inch outer rim width wouldn't benefit on gravel from a bit more width like 3? inches 4? enough to make the flares actually worth while? I could carve up the wells and run 14s!!! which yes could fawk my gearing... but I think I can find rally tires not much taller then my 165 65 13 in a 14... and that opens up a world of cheap VW rims and used tires. Cause I know Chris Kepksi has a huge inventory he needs to unload


I can go as simple as making some wheel spacers... or I can go full hog and build full bespoke suspension with inverted shit (it's been sitting around here long enough collecting dust) and lengthened control arms... and the try to tune that beast... or

I can go back to my hole in the wall, drink beer and dream of winning Dirt (wait, is that the cornputer game da kids are playin' these days?)

Okay...

check 1-2, check, check, is this thing is on?... please see here (for more background)

https://www.rallyanarchy.com/phorum/read.php?5,43590,page=3

I have some um, dubious inverted billies... some sorta "jdm-b-spec rally crap" from a immmpwneza or maybe a legacy... I can't remember... but they are 40 mm tubes, and have a whole wacking 7" of travel!, compared to my 5.5"! (wait... that sounds bad) soooo... damn the torpedoes. gawd another bad euphemism...

If I'm gonna build semi-somewhat-super-beeching-suspenderners, I need to think tubes and bearing bushes, and clearances and schtuff.

The stock justy stuff is inside a 45mm tube... this fits in the knuckle as a pinch, not welded eyes. For the time being I would like to keep this config, so I have back-ups in the stock (my modified sheet) stuff...

Fwiw, I have never broken suspension... pounded it yes, but never bent anything without sliding into a rock first that knocked out the whole subframe... so...

first pic is the stock Justy left with the 40 mm billy right... same OA length! and even same thread! wow! might be able to use stock tops... but that may change, not part of this current discussion.

Question 1: Tube sizing... so.. these fit in a 40X45mm tube... of which I have some (stock tubing) but there is no space for a bush, so if I turn it out to fit even a thin bush, wall sie is getting thin... then if I thread the outside for a spring seat... even thinner... I could add a sleeve or the threading. but is 1.5 mm to thin for a tube??? it seems thin to me...

I have some 2"DOM that is like 45mm id... well 2" DOM 120 wall, that I could bore... Oh yeah, I have a real lathe. Then I could sleeve and weld in the 45 mm tube to fit the knuckle, gives me lots of meat, and lots of room for big fat bushes. But seems overkill? I see "rally spec" bushes for the 40 mm billies are 42 mm od, so maybe my 45 mm tube is okay???

1.75 DOM is pretty close to 45mmm and I have some of that on hand (right of billy first pic)... I could make the tubes from that...

but I could just use the stock tubes (second pic) here in a rear tube I had cut open...



Thoughts?