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NickJ's Lada Niva TwinCam


NickJ

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Wof time!

Having some time on my hands I got stuck in and gave her a good once over, making a list of to do;

Steering box play - adjust

Steering idler play - adjust

Stuffed tie rod end - replace

Rear brakes - adjust
Check valve clearance
Transfer case alignment

Check for any rust and treat
Clean out the dust in the rear lights

 

After a few days crawling underneath and beating the tierod end with no effect I borrowed a tie rod splitter of h4nd which worked within 5 min, talk about correct tool for the job!

Steering box and idler adjusted up nice, steering is much more responsive now (for a lada) 

Transfer case alignment I managed to get better but looking at it the vertical position is correct but for some reason its horizontally out, never seen this before and am thinking the engine has shifted a bit on its mounts, its not causing much trouble so i'm planning on keeping an eye on it in case anything changes.

Wof check went ok except for a tyre, uni joint and rear brake balance so pretty chuffed with that, quick lap of town to pick up a new tyre and uni joint and she's back to legality again.

With all that done, its time for a photo, unpacked a few flashes and set up in the driveway

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Also sorted out a mount so I could hook the choke cable up to the carbs, its going to be so much nicer to start in the mornings without having to tie the choke back and then having to stop once the engine is warm!

 

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  • 1 month later...
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Well got the wof and celebrated with a big drive up the Hopkins, for those of you not familiar with the south island you head to lake Ohau, drive past the skifield turn off and from there the road turns to a track with vehicle access almost all the way to the main devide, its a great spot, our plan was for a spot of hunting but the weather played against us, snow to the valley floor and a nasty southerly, we made it to the ridgeline but the temps didn't allow us to hang out too long!

For the trip I finished off a longstanding mission, a plywood platform in the back to keep my gear organised, also has a compartment for the second battery to calm my fear of returning from a mission in the hills to a flat battery! not quite wired up yet but its there with jumper leads attached if needed!

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This mudhole claimed the niva, with armfulls of river stones and my high lift I managed to dig myself out, all alone because the plan was to meet a mate up there late in the evening, I made the call to drive out and wait for him, saving further troubles and of course we both drove back in without incident! I also had the first test of the light bar, its the best thing ever for night trips, perfect view of the dark track ahead.

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Happy Niva

 

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Stoked as I replaced the bald tyre with another mud grip, going cheap could have been a disaster!

I was pleasantly surprised with the performance of the engine, in low first she happily idled across rough sections and had enough poke to get off the idle and climb out of creekbeds.  :) 

Back in the city she's been dormant but I take her out to the farm now and then, until last week I left her to warm up and got distracted by a phone call, with a change of plans she never left the house and sat for a few days, when I tried to start her up again, no dice, not a pop, thinking it would be the points I pulled out the distributor and gave it a tickle but still no life, checking the plugs they had a solid layer of carbon! idiot! so quickly stealing the 2105 plugs she roared into life, lesson learnt, choke is wholesale pouring in fuel and should only be used to start, not idle!

 

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  • 3 weeks later...

Possibly an embarrassing post but hey.


Had a close look at the carbs again today to sort out the flat spot focussing on the accelerator pump circuit. Being there is slack between the actuator and the diaphragm that I can't adjust out this was the target.

With everything looking right I took the diaphragm out to check if for some reason I brought the wrong one, cue the i'm an idiot moment.......

Turns out I never replaced the return spring when I rebuilt the carbs, quick check of my parts box and there they are, 5 min later, back together, a quick test drive and once again another leap forward in drivability.

Anyway, pics

Before:

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The little spring:
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After:
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Looks like it needs a clean too!

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  • 1 month later...

Sad day for the Niva, with the dellortos not quite how i'd like them and running a little rich (expensive!) I made the call to swap them out for the standard carb because I have so little time and don't want to inflict any further damage if things arn't right.

 

Only took 1/2 an hour to inflict so much pain, the test drive was rather quiet and boring, its either down on low range torque or induction noise = torque, either way sad, boo!

 

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anyway, reason to kill the original carb is because its stuffed, freeplay in the shafts, wear around the butterflies that won't seal and worse of all the idle mixture screw is poked, if anyone has a spare i'd love to talk, even better a servicable weber dhs 34 or derivitive? will throw up a wtb to for good measure!

 

post-18600-0-41735200-1443424110_thumb.jpg

 

Any takers?

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  • 4 weeks later...

With comrade Baxter in town, a quick tour of the countryside was on order

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If you think two Niva's in one place is impressive, hows this, THREE!

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The white one was rescued from the scrap heap and is being brought back to life here in Canterbury, it has a 2L twin cam and will be back to road legal shortly. 

 

Apologies for no fixit photos, it would seem being parked between two Toyotas for so long offers some form of herd immunity from reliability issues.

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  • 4 weeks later...

Had a package turn up from Azzurro containing the shell and internal goodies of a weber dhs carb, from this I hope to sort out the horrible idle i've been putting up with from blocking off the idle circuit due to the above broken idle mixture screw, and that the shaft is terribly flogged out on my carb!

 

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The body he supplied had stripped threads on the accelerator pump but I saved that by finding some longer screws to reach what little thread is left and opened up the worst hole from M4 to M5 to hold the whole lot together.

 

With a good clean its all back together and for the first time since removing the twin carb set up I have a steady idle, i've only managed a quick drive around the block but everything feels fine and she settles to a nice 800rpm idle quite comfortably.

As i've been using the 2105's idle screw to block the idle circuit in the niva, it was duly reunited and I had the joy of two magnificent pieces of russian engineering purring away in the driveway.

 

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  • 1 month later...

Started a new job for the summer and being an easy bike from home the Niva has been a little neglected, amusingly last time it drove we had to push it through the Mcdonalds drive through on Riccarton road because of flooding (surely another bucket list item for the lady ;) ) sadly I couldn't work it out at the time, some gremlins for sure, so today I had a closer look, taking the air cleaner off I found the top plate of the carb was loose, that can't have helped! but while I was there I checked the float and needle valve before securing everything in place, for now it seems to have helped, idle is a bit rough so might have another slight blockage or airleak to find.

Moving on the temp gauge was doing a few odd things so I pulled out my thermostat testing rig:

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All is happy, nice smooth opening, now to look at another possible temperature culprit, for some reason I've been loosing coolant, i've been passing this off as a radiator leak so made the call to pull the radiator out, give it a clean and see if any solder needs a touch up, once again all happy, feeling somewhat confused and being that I had the whole cooling system open I picked up some coolant flush and ran it through, on heating up the system the radiator cap started spewing out foam....
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Left is the replacement Repco gave me when my original fell apart, right is the radiator cap from the 2105, that explains alot! pretty much running an open cooling system the coolant has either leaked out the top or boiled off, will have to start another shopping list from the Ukraine!

Merry christmas everyone, hope you all have some adventures over the break and drive safe!

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  • 1 month later...

Seems the flooding issues I had are most likely due to spark plug fouling, I have a set of BP6 plugs to try instead of the BP7 that its had since I got my hands on it, fingers crossed!

Also failed a wof last week, few small things but mainly the lower front right arm was loose, bloody stoked they found it, hopefully that takes care of the mystery clunk!

 

It appears that the bushings have seized to the bolt not allowing it to tighten up, so after a trip to pick a part for a new arm bolt, and a call to a mate for new bushings, I assumed the position:

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A bit of grinding and swearing later....

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And we're back together, thankfully I had the 2105 looking on to help out and a hefty assistant to show me not only how a hammer is swung but for having a shed full of lada bits including a brand new set of suspension bushings :)

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  • 2 weeks later...

With the wof in hand I set out with a bunch of other Niva owners for a trip around Molesworth Station

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After 450km of mixed road and easy gravel I had chewed through almost 2 tanks of gas, not optimum and should have done that on a single tank! so today I pulled the carb and checked a few details

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Even thought the carb I got off Azzurro has the book jetting, its larger than the original single of the same dimensions. I've now swapped the original jets in and hope that improves the fuel consumption.

 

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  • 2 weeks later...

Yesterday I took the Niva for a short drive, upon starting to head home she decided to have a throwback to the 1800s and billowed steam out the exhaust, with not a bucket of coal to be seen I took this as a bad sign and shut down. Removing the plugs for a look showed coolant in #4 so I left the plug out and made a noisey crawl home.

pulled the plugs again this morning for a look and found this:

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not a good sign! 

 

So head off and hope that its the gasket and the head doesn't need machining as it was on its last legs last time I had it planed....

 

Lada/Fiat gods please smile on my modest wheels.......
 

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Well I think the gods are smiling in the Canterbury sun, it seems like the gasket has let go, the reason why i'm not too sure

 

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Lovely steam cleaned piston, BHG is way better than techron!

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I was quite glad to see that crack, it appears the gasket has just let go, possibly a lack of torque in that end? I'll get another bolt of the same size this week and make a chaser to clean the threads the best I can before ordering a the new gasket.

 

Also fears of warping the head are gone, straight edge only has a very slight amount of light shining through if any when I put the torch behind it, and thats around #1but might try sneak a feeler gauge under tonight to double check.

 

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The scratches on #4 are from the last time I had it off and it slid in the car on the way home from the machine shop, luckily they are well inside the gasket.

 

Also the water jacket holes in the gasket get larger toward #4, I guess this is to address the lower coolant flow that i'm told plagues these engines, anyone know if they should be opened up more to better match the porting?

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The plot thickens....

 

Today I called Gavin at Euro - Italian Car Parts to see what head gaskets he had in stock, confirming size and thickness I measured up the bore, its 4mm smaller???? taking further measurements, 80mm bore, 80mm stroke, for a 1800TC it should be 84mm bore, 80mm stroke, seems I was told wrong when I got the motor and it is a 1600, that means the last head gasket was too big (see image above, doh!)

So with this i'm certain the gasket failed due to the steel band being too close to the water gallery under the split and the correct gasket should solve the trouble!

 

And, the jetting i've been setting up is all wrong, maybe i'll get further economy......... maybe

 

yay!!!!!

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  • 1 month later...
  • 4 weeks later...

Something something single carb til I have time for the dellortos....

 

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Surfaced the manifold to get a better seal yesterday, just need to fabricate a better linkage mount and they'll go back on.

 

 

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  • 4 weeks later...

When I took the car for the first test drive after the HG fix things didn't feel right, stumbling at cruise and slightly rough off the line, in a fit of rage (drawn out over a week or so) I prepped the twin carb manifold and swapped the dellortos back in, cos if i'm going to mess with carbs, i'm going to mess with carbs worth fiddling with! Ultimately i'm sure the issues were just gasket/ airleak related and would have been an easy fix but where's the fun in that!

 

I now have a nice sounding engine :)  tuning is a tiny bit off but I need to remove the battery to get at the ports to check balance between front and rear but it drives, and knowing the rings really need to be done I can't complain too much!

 

Dort on :)

 

And because picture less updates suck, here's a stag on the alpine fault near big bay to chew up your data:
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  • 1 month later...

Interesting few weeks messing with the carbs, had issues with cylinders not doing much on idle, pulling plug leads didn't change anything. I tried all sorts of fiddling looking for manifold leaks but couldn't track it down. Guessing this was connected to the idle adjustments not doing much on the same cylinders I pulled the jets for the 100th time but this time flushed the passages resulting in near instant success, much happiness!

 

Keeping track of fuel use I'm getting 250-280km/40L tank around town, that equals the open road use pre head gasket, need to find time for an out of town trip and hopefully be back to 400km/tank open road. I have suspicions the pump jets are a little rich from the way it hesitates at low revs, I'll give them a tweak and see how it responds.

 

A few weeks back a differential air pressure sensor turned up from ali express, i've had it running on the work bench and but have waiting on a screen to also arrive so I can hook it up in car to balance the carbs, bit more hi-tech than a clear pipe filled with oil i've used in the past (and quite likely less effective).

 

Today, still waiting on the screen I decided stuff it, lets just do it with the computer:

 

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Bet thats a sight not ever seen before, tuning a twin carb Lada with a computer!

 

Things didn't go too well, with the sensor hooked up to the ports on carb #1 during the first run readings were full scale each way due to the pulses from each cylinder, to fix this I sampled at a higher rate and played with a time average over a set number of samples, this smoothed things out slow enough I could read directly off the screen. Opening a balance screw right out increased the pressure value while turning it right in decreased. Assuming this may have been a fluke fluctuation I tried again to the same result, bonus! I gently adjusted things to get a mid range value and closed the vacuum port only to find it had a residual leak, with darkness falling I've left it for now, but will fix the leak, re-test and hopefully confirm my balance made with the tube & oil method (which should be near perfect) 

 

If the screen ever turns up I plan on making a simple bar graph to show imbalance between the ports which should be pretty cool!

 

 

 

 

 

 

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Typical, bloody screen turned up today!

 

Had a quick play and set up a script that took the value from my average pressure deviation and plotted it as a bar across the screen.

 

Worked swimmingly when I blew in one tube, but pressure on the other had it inverting at half range, from a minor oversight in pressure difference from the pulses being way over the 2kPa sensor range it looks like i've destroyed the poor thing! No trouble though, i'll source another with a higher pressure range and go from there

 

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Cancel that, sensor is fine, I changed the rolling average count to try a different method and it all works fine, seems to be something in the values I'm using, hmmm.

 

Thoughts???

 

//oldschool.co.nz/index.php?/topic/45307-nickjs-lada-niva-twincam/page-4

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  • 3 weeks later...

Looking at heading down south in the coming weeks so dragged the Niva from the shed to give the carbs some decent attention.

 

With the balancer coded nicely I hooked it up and got both carbs sorted in under 5 min by balancing each one individually then checking between the two while adjusting the linkage until the graph read even, I'm quite astounded by how simple and effective the gauge worked!

 

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Hooked up, bar graph is to the right, indicating more vacuum in the right hand port.

 

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Adjust bleed screw until the bar graph was centralised, and done!

 

I found the graph still bounced around the zero point a bit and I need to add some kind of damping in there but i'm unsure if it can be done with software or some kind of chamber in the lines to the sensor would be better, leaves me some pondering for the next few days.

 

Made a shortish drive out to Sumner and back without any issues so i'm reasonable confident everything is happy.

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  • 6 months later...

Niva has been having a long rest while I sort out the rocky transition to the working world. After the last big push the lack of compression has bugged me so out the engine comes again for a bottom end rebuild.

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My fix to the terrible placement of the bottom hose and no drain. (Just cut the bottom corner to prevent coolant going everywhere!)

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Engine bay is now mostly empty, head is on the workbench, just the rain came in earlier than I expected damping my enthusiasm to climb under and release the lower bell housing bolts.

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Once the block is out i'll strip it down and assess what parts are required, hopefully just rings and bearings and no major machining!

I've also ordered a 14point7 SLC Free unit with the aim of tuning the carbs to better fuel economy, digital times ahead.

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I now have an empty hole!

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Initial plan to remove the engine has gone overboard, figuring it was too hard a job by myself and much easier with the gearbox out I crawled underneath, once underneath the gearbox was going to be an easier job with the transfer case out......

So new seals and maybe bearings for the transfer case, along with a tidy up. Also she's been running a 4 speed box so i'll take the opportunity to close up the 5 speed i've had waiting around and throw that in too.

Carefull removal of the sump shows where the oil has been escaping through the gasket from beside the oil pump

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This coincides with where a small corner was removed and obviously removed a bit too much stiffness, bugger.

Removing the crank gave a surprise, bearings were just lightly scoured, I was expecting much worse due to oil surge issues encountered due to poor design of the fist sump I made, these really are tough wee motors!

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This is where the phone battery died and you'll just have to trust me that the pistons and crank are healthy, just well worn rings all round and one broken on #4. With my cheap verniers I get an 80.0 bore but i'll sneak it all into work this week and double check with decent measuring gear, fingers crossed for a quick hone and back togetherness!

 

 

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