Mechanical Sympathy

I'm all over the place with this ,so I went back to basics. Standard timing, set correctly (I don't want to talk about it) with vacuum advance connected. Runs a little bit better. But still there's a miss/spit/bog when progressing off the idle circuit. I can advance the timing but the issue persists I've chased vacuum leaks, idle tuning, timing issues and I'm fairly certain I can eliminate those concerns. I even discovered the air bleed screws weren't seated. Still no good. So I think that means it comes down to jetting. I perceive the DCOE 151 is set up for a 1300cc engine. The fellow/place I bought the carbs from was no help - doesn't stock jets and told me that a 1600 at 5700rpm is the same as a 1300 at 6000rpm. On the face of it, I concur. But in practice.. its definitely bogging when I try to floor it or progress from the idle circuit. The 151 DCOE comes with 45/F9 idle jet - seems fine 30mm chokes - fine 115 main (120,125 would seem ideal for the choke size, a little bit richer) 200 air correctors (my reading suggests main + 50 is ideal = 170 air corrector, richer) f11 emulsion tube (my reading suggests f16 or f9 for a 400cc cylinder size) accelerator pump gives a healthy squirt - haven't looked into sizing So I'm thinking to order/buy a pair of 120/f16/170 (main/emulsion/air) jets. Wish there was someone knowledgeable I could ask about it!

I share your apprehension! I'll certainly check it again tonight before advancing further. I might even knock total advance back to 32 degrees to begin with, and work up to it. edit: I'll leave it to the weekend and take my time going over it, and with more light. edit edit. I've been doing something wrong all along but I don't want to say. The temptation to go out and fix it this late is nonetheless impossible.

It was quite interesting reading! And has given me the confidence to push past 40 degrees. I still don't know the specs of the pistons yet - because I haven't been asked to pay for them (yet!). I'm guessing the compression ratio has been bumped slightly by increasing the dome, which has the double effect of pushing the required advance even further BTDC, as well as making them even more resistant to ping. I'm just shy to push the friendship, but push I must. Looks the distributor will need the mechanical advance recurved or cold starting could become problematic.

A few weeks between updates, indicative of the ongoing troubles I've been having, and the time available to get to it. I've been able to tune the idle just nicely thank you. But then when I'd try to fine-tune it and go for a drive, everything would go pear-shaped. At first I assumed carb jetting was the problem. Well it's seems that I forgot all my early reading about Webers. Of course now I realise that Webers have no port vacuum and the 2TGEU EI distributor (and probably most others?) requires port vacuum - not manifold vacuum. Duh. So every time I tried to move out of the shed, the timing would become hopelessly retarded whenever manifold vacuum dropped. I purchased a proper timing light and that's when I realised the error of my ways. I've now disconnected the vacuum advance and trying to tune it on mechanical advance only. This has been quite a bit better, but I'm not quite there yet. I'm up to 38 degrees total advance and it's still farting around like it's retarded, though it's running well enough that I'm now able to street test it. And remarkably still starting ok with 25 degrees initial timing, though it needs to be nursed until warm So I put it aside last night, nervous about pushing it with more advance. Nervous for my custom pistons! I began reading about hemispherical combustion chambers and domed pistions I now realise this results in very slow flame propagation. But also makes them very ping resistant. Chrysler Hemi engines even ran up to 45 degrees advance back in the day. Tonight I'll have yet another go at tuning at 40, 41 even 42 degrees. Anyway, it's made it out of the shed again for a dust-off wash. Time for a good buff. I've got a bloke lined up for a mod plate and roady when I'm done.

Richened up 2 & 4 until they stopped spitting and now it runs grouse. Right on my self-imposed 9pm rev curfew too.

I found I had to convert to a KE30 booster/master cylinder/proportioning valve combo to fit twin Webers on that side. And it looks like Jordan has gone up a plate size on his mounts. The new T50 mount looks much neater than my early angle type. I might have to hit him up for anothery.

Well... what a difference a properly adjusted timing chain makes! Now to just tune these Webers. Had to cut it short last night because I'm not sure if the neighbours are as enthusiastic as I am. I expect I've got a vacuum leak somewhere. I'll try disconnect/plug my gnarly PCV system and see how I go from there. Love the sound of them.

I pulled the cam cover off a couple of times to be certain! With the bonnet down and the door closed all the rattles disappear, so maybe ignorance is bliss?...

After running around for multiple fitments of fanbelt, last minute hose clamps and running-in oil I popped the cover off to confirm #1 TDC to install the distributor and plumbed everything else. It's all up an running now. A couple of niggles to sort with dash and gauge wiring - something has gone awry there and it's annoying me. The timing chain seemed awfully noisy to begin with but seems to have settled down. Of course I'm nervous at any little clatter or rattle but it strikes me that the 2TG is a bit of a rattler anyway. can't wait to get home tonight and rev it a few more times, maybe drop the running-in oil.

You're off to a great start there! Keep at it.

KE Conversions make mount kits for the 3S so it is certainly possible. I think your project will will be easier if you can source a sump and bellhousing/gearbox from a 2S powered Corona. Nonetheless all the details are in his "for sale" post here on Rollaclub, and he also has a Facebook page.

I'm just about in! I'll be around all day Sunday Mat if you'd like to drop by? Hopefully it'll be running by then. I've just put down a couple of kegs of zesty homebrew.. Dave I'll certainly have it out and about in the coming months! Off to SCA tonight for plugs/filter/fluids.

Well it turns out I had to take my own photo of the pistons. But I'm ok with that!

Haha I know right! I figured just do it, with some healthy peer pressure of course. Sitting on the train just now got the call that the pistons are in so the they'll get on with the build. Diamond brand pistons. I've asked for a photo before they lock them away.

The engine was pulled down and it had spun #1 conrod big end. As a result the piston was tap-tap-tapping the head. And all the pistons were shot. A couple of weeks later, presumably after a clean and measure, I had the quote and gave the go ahead. The head will get a full recondion, custom forged pistons to suit the 'EU squish chamber head, and bottom end rebuilt and balanced with the flywheel. Standard cams, because I'd just like it to be punchy around town. Hopefully there's a lift in compression from the pistons & rebore & reface but I'll leave that to them. "Pump fuel". Should be good for 20+ years of Sunday driving! Forged pistons with a late/last model head is probably not the usual 2TG rebuild but I'm just going with it rather than try find an early head. Bit of a lead time on the pistons I understand haha

Well it's out again. Time for a quick freshen up. I'll keep you posted if the scope of work expands. I've also given it it's first rub back since i painted it with 2000 grit and a quick polish, which took care of a lot of orange peel. Needs another rub in places and a decent buff.

Oh I'd love me a KE17 Sprinter. Nice buying.

Haha too high for mower blades #antistance

Yeah that's it Dave. If it had "oil injection" it might be able to keep the compression up, but I haven't been able to keep it running on all four reliably. I am also hoping that it's basically fine, just needs a freshen. Seeing that pic on a desktop PC today highlights that I could give it another 2000grit/buff/wash in the meantime!

Yeah I'm gunna pull it. Suspect compression ring on (at least) #1. Basic re-ring and re-bearing is what I'm anticipating. Gazzard Bros. the leaf spring kings will come pick it up and we'll take it on a Saturday road trip to Abbott's.

I'm certainly trying to temper my excitement for the moment! I ran it for a good 15 minutes, until all the smoke cleared and I began to worry that the neighbours might not be as pleased as I was, that late on a school night. I'll reset the mixture screws this evening and "turn it around" in the street, then check the plugs and re-test. If it's good I'll pledge to honour my bets/clamp the battery/go crusiing in <month! So grateful for all of your input.

Mat I think I owe you $5. 20ml of oil syringed down each plug hole with testing in the prescribed method and it blew this; So I set the timing and it fired right up and ran happily, as if the rings had come unstuck from the pistons. I hope that's it resolved. I should have posted my woes sooner. Thanks all! So, mod plate, roadie.

Fair call - all and any help appreciated! No being a relative noob to engine troubleshooting, I pulled one plug at a time and didn't open the throttle. In hindsight there's probably not much to compress in a vacuum. Though at least the results were repeatable (and repeated). Back to the shed this evening then for a re-test... with some luck a bit of residual gecko egg will fall off a valve seat, or something along those lines.

Whereas these were the plugs I pulled when I first got the motor (in 1234 order). They gave me some confidence that the motor had been ok.

Yeah, short of fitting the special service tool / cam key the cam timing appeared spot on. Futhermore valve clearances (measured while at operating temp) were all to spec and within range. All of the shims spun freely with no signs of chatter. No water in the oil, no oil in the water. A few drops of oil before another compression test sounds like a good idea, to be sure.