Lachlan's 1972 Datsun 1200 Sedan

[Lachlan]

On 9/16/2024 at 7:42 AM, Lachlan said:

The tyres scrub a bit when reversing so I’m guessing it still needs an alignment.

 

This turned out to be coming from the front disc brakes. I discovered this when I had the car up on stands for "Pitman v. Lachlan, The Return." I haven't narrowed down the cause, but they judder / grab when going in reverse and especially if the wheels are turned. It makes reversing into spots at Cars & Coffee a bit entertaining for onlookers. Any ideas on what to check? I can confirm that the discs are slightly warped as you can feel it when spinning them freely and when braking for traffic lights. This was even after having them machined while rebuilding the brakes in a previous year. I'd read somewhere warped rotors can cause the above issue that I'm experiencing due to the pad wearing in certain places. As for the actual caliper / disc / pad combo, it's some weird PBR mix again so that'll be no help.

 

Things to check? Time for new discs and pads?

Edited October 19, 2024 by Lachlan

[datsunfreak]

19 hours ago, Lachlan said:

Time for new discs and pads?

 

If you can get them, yes. Definitely. 

[datsunfreak]

19 hours ago, Lachlan said:

I discovered the reason the kick-down on the trans wasn't working was because a wire had detached on the pedal switch. A short soldering job later and the kick-down works again! Comes in hard and super handy for accessing the upper revs on hills.

 

That's awesome!

 

19 hours ago, Lachlan said:

It consumes a fair bit of oil. After only a few weekend outings, it's already down to halfway on the dipstick. I knew it burnt some as there is always that smell when idling and I can also see a little smoke when flat to the floor on the freeway at night (lights from the car behind makes it easy to see). I suspect there will be a valve seal and piston ring replacement job coming up.

 

As I may have mentioned, replacing the valve stem seals with the engine in the car isn't too tough, but neither is removing the head. I would definitely start there.

 

19 hours ago, Lachlan said:

And because it wanted part of the action, the carb float bowl gasket decided to start leaking. Yes, "Weber the world" and all that.

 

Don't worry, I wasn't going to say it again.

 

 

Probably. 😋

 

19 hours ago, Lachlan said:

At least when I took it to Cars & Coffee this morning, it really appealed to the over 60s female demographic. I don't know whether to call that one a win.

 

I would. But I am old. 😉

[RyanC]

I pulled the head on the ute in the garage used the tray pulled all the valves and put the beast back together over a few nights.  If I had a whole day def doable on a Sat or Sunday.  Should be able to get a VRS kit and timing kit for gaskets and valve seals.  

 

That could just be fuel burn in the rear with lights at night be interesting if she smokes under acceleration or when you back give it some stick and then close the throttle.

[Lachlan]

Compression Test

 

I loaned my ball joint separator to a friend and borrowed his compression tester and was finally able to get some good data on my 1200’s engine health.

 

Dry test on cold engine - full throttle, 7 cycles

#1: 158

#2: 170

#3: 170

#4: 160

After much reading, I put a capful (tablespoon) of oil down each cylinder and repeated the test. As the results showed, it was way too much for the small capacity engine and made the results worthless. Lesson learned.

 

Wet & cold

#1: 250

#2: 300+

#3: 300+

#4: 300+

 

Adding insult to injury, on the first wet test the gauge decided it wanted to become better acquainted with the radiator and fan, wedging itself in between the two and whacking the gauge a couple times. Now the needle doesn’t return all the way to zero anymore. Looks like I just bought myself a compression tester.

 

I videoed each test and will compile it later.

 

Oil Consumption & Leaks

 

I’m chasing a problem of excessive oil leaks from the lower part of the engine and increased consumption. The main culprit appears to be the oil pan gasket but the rear main seal could also be involved. I was thinking that excessive blow by was causing an increase in crankcase pressure which was blowing oil past the seals. This seems less likely now based on the above compression test results.

 

I was also thinking the PCV valve could be playing a part because some time back I swapped in an aftermarket part e.g. cheap. I have since learned that these engines work best with genuine or quality aftermarket PCV valves so I might order one shortly.

 

Lastly, I will also replace the valve seals and see if that makes a difference as I know that is an issue on these engines if they haven’t been replaced.

 

Anything else I’m missing?

[datzenmike]

Half your quart oil in a few weekend outings would be terribly noticeable as a thick blue cloud. Though it may be burning, it's likely that leaks are the major cause. Place a sheet of cardboard under engine and transmission after driving and check in the morning. I find valve seals blow most after sitting and then started. Anyway it's an easy fix without tearing down the engine and the seals are cheap. Stick a few feet of rope in the plug hole and by hand, turn the piston up toward TDC on the compression stroke. The rope will fill the combustion chamber and you can remove the valve spring without fear of the valve dropping and change the seals.

 

Compression test is excellent if the gauge can be trusted. I can't explain the compression doubling from a single tablespoon of oil. If those lower reading are correct it would seem the engine is in good shape and oil leaking is the cause of loss.

 

Differential: There is a drain bolt on the very bottom of the axle housing that is easy to access. They usually have a square hole that a 1/2" ratchet end will stick into. The fill bung is identical but has a magnet on it. It's also smaller than 28mm.

 

Judder when reversing is possibly the front clutch not holding properly or the reverse brake band, but this is adjustable. The piston stem should be torqued to 9-11 ft. lbs. then backed off two full turns and the lock nut tightened to 11-29 ft. lbs. You had better confirm this setting.

 

 

[datsunfreak]

3 hours ago, datzenmike said:

Half your oil in a few weekend outings would be terribly noticeable as a thick blue cloud.

 

It wasn't quite half the oil, just the level indicated on the disptick was halfway down. That should be not more than a liter/quart. 👍

[datzenmike]

ok Still a lot.

[Lachlan]

On 11/18/2024 at 9:34 AM, RyanC said:

I pulled the head on the ute in the garage used the tray pulled all the valves and put the beast back together over a few nights.  If I had a whole day def doable on a Sat or Sunday.  Should be able to get a VRS kit and timing kit for gaskets and valve seals.  

 

That could just be fuel burn in the rear with lights at night be interesting if she smokes under acceleration or when you back give it some stick and then close the throttle.

 

While I didn't have to pull the head, I was able to replace the valve seals in an afternoon. Admittedly, it was a long afternoon and I nearly chucked a tantrum. More on that shortly. I ended up grabbing a Permaseal kit in the Supercheap Boxing Day sale. Thanks for the tip about the VRS gaskets. Where did you get them for your ute?

 

I suspect you're right about the fuel burn. I'm beginning to think it has been running rich for most of it's later life and I'm only now returning it to leaner burning. Still not finishing sorting the issues, but they are currently being worked on.

 

On 12/10/2024 at 1:45 AM, datzenmike said:

Half your quart oil in a few weekend outings would be terribly noticeable as a thick blue cloud. Though it may be burning, it's likely that leaks are the major cause. Place a sheet of cardboard under engine and transmission after driving and check in the morning. I find valve seals blow most after sitting and then started. Anyway it's an easy fix without tearing down the engine and the seals are cheap. Stick a few feet of rope in the plug hole and by hand, turn the piston up toward TDC on the compression stroke. The rope will fill the combustion chamber and you can remove the valve spring without fear of the valve dropping and change the seals.

 

I agree with you that leaks are the likely culprit. I'm focusing on the oil pan gasket as that is leaking badly. Valve seals are done now too so that will help. The cardboard under the car is consistently soaked where the engine joins the transmission (auto) and it drips off the bellhousing / transmission after running along the pan. And thank you for the rope trick - that was a winner and meant I could take my time with each valve.

[Lachlan]

I've been taking 'Doris' Datsun on errands and coffee runs and she is a little weapon! I am surprised just how right Datsun engineers got these things in the early 70s. While I'm from a different era to most of you, these simpler vehicles resonate and I'm beginning to understand the Datsun disease now. That said, it's still complex enough to keep coming up with new issues that need me to fix.

 

The latest one is the temperature was climbing higher and higher on extended freeway runs (20 mins or more). From reading other Ratsun posts, it looked like the radiator was at fault. When I parked after the most recent drive where the temp was getting uncomfortably close to H, I noticed that the overflow bottle was empty and there was coolant sprayed around the engine bay. I opened the radiator cap (cold) and the level was below the fins with muddy sludge in there too.

 

I took it to a radiator shop to have it cleaned, pressure tested and fixed if possible. They determined that half the tubes in the radiator were blocked solid. Time for a re-core.

 

While the cooling system was drained, I took the opportunity to replace the thermostat as I knew that was stuck open. Here's what I found when I removed the housing.

 

 

Yeah, no thermostat. That explains why it took an age to heat up and ran terribly until it did.

 

I've also noticed that the exhaust manifold heat stove/riser is completely stuck which would contribute to the extended poor running when cold. I've tried to gently get it moving but it is really stuck solid. I don't even know if it's stuck 'closed' or 'open'. I'll keep spraying it with WD40 and my homebrew penetrant of acetone and trans fluid and see if I can get it moving. Otherwise, I'll have to pull off the manifolds and dunk it in molasses for a couple weeks. It works, albeit glacially.

 

In some good news, here's a shot of the spark plugs. These are the best they've ever looked in the time I've owned the car.

 

 

Still a bit of oil in the holes though.

 

Edited January 12, 2025 by Lachlan

[Lachlan]

The valve seals have now been replaced. After putting this off for too long, I finally bit the bullet and purchased a full gasket kit which included these.

 

As this process has been explained many times before in other posts, I'll just show pics and limited comments in case this helps someone else.

 

Here's the rope trick often suggested on Ratsun.

 

 

 

Spring compressors are deadly. I had one spring let go multiple times.

 

 

 

Below is a valve collet. It hold the valve up in the spring top plate and needs to be removed after compressing the spring. It's in two pieces and I found it easiest to use a pick to lift each piece out before lifting the entire spring out to expose the valve.

 

 

Here's the actual valve seal that is the whole point of this exercise. Pull it off, put a new one on. I dripped a bit of oil on the inside before wedging it down over the valve stem so it had less chance of tearing.

 

 

I spent an age trying to figure out where the o-rings went that the service manual mentioned. Then I realised they weren't installed by the previous mechanic.

 

 

I found a 5/16ths socket to be the perfect size for pushing them in around the valve collet.

 

 

Job done. Onto the main course.

[Lachlan]

Oil leaks have plagued me for some time. I put off tearing into the oil pan gasket because I didn't want the car off the road for that long. I also was unsure what to 'fix-while-I'm-in-there'. After some reading, it seemed that now was the best time to also do the timing cover gasket and front crankshaft seal. After finding the sludge in the cooling system and reading about removing the water pump to really flush things out, that sealed it. This has now turned into a bigger job.

 

Thanks to many previous posts, I was well informed that it was going to be a challenge getting the oil pan off with the engine in the car. Give the choice between lowering the crossmember or loosening the oil pickup bolts, I chose the former. Given my recent success refreshing the steering system, I knew I could suspend the engine from above and remove the supporting structure underneath for greater access. Here's my totally safe and shadetree approved setup.

 

 

Don't worry, it'll be fiiiiiiiiiiiiiiine.

 

Once the engine was supported, the engine mounts were released and the engine lifted from below with the trolley jack. The straps up top were providing additional support so the strain wasn't all on the bellhousing and transmission shaft. I unbolted the crossmember and it gave a bit more clearance to get the oil pan past the oil pickup.

 

BIG TIP: With the pan free from the block, try rotating it 90 degrees instead of going straight forward. I found this worked for me in getting out without even touching the oil pickup. I unbolted the sway bar but you don't need to do this at all.

 

Here's the bottom end of the A12. Cool little thing. Never seen the bottom end of an engine before.

 

 

I found this spring in the oil pan. Anyone know what it might be from? I can't see anything missing anywhere.

 

 

Here's how things are looking right now. The timing cover is really stuck on. I'll have to keep massaging it to get it off. I've resisted prying as I don't want to damage the gasket surface and create leaks.

 

 

Here's a quick story that I forgot in the valve seal post. The spring compressor has a c-clip keeping the spring plate bracket from falling off. Somehow it came loose and fell onto the head after I released a spring. I watched it bounce down into an oily hole and stick to a pushrod. Blood pressure immediately rising. I rapidly turned off the music, ripped off my gloves and frantically grabbed a pick. Carefully, slowly, pick up the c-clip ... NO! ... dropped it right down the hole. I nearly died right then.

 

My wife heard me assessing my life choices with imaginative language and came to watch / help. After I'd explained the cause of my malady, she casually suggests using a magnet to fish it out.

 

"I don't have one ... wait ... aren't my screwdrivers magnetic?"

 

Had it in my hand within 10 seconds after a single dip into the abyss. She is worth her weight in gold.

[RyanC]

Hey mate your getting in deeper 😄 

 

I got the vrs from eBay.  

 

Hope she goes back together straight forward and your other half sounds like a keeper.

 

 

[datzenmike]

 

My guess is this is from the timing chain tensioner. It's a teflon or nylon coated plunger with internal spring that bears on the slack side of the timing chain to help keep it taut. If the timing cover was off you would see it. Someone had the chain off  or worked on it and lost it down the front and it ended up in the pan. If you buy a timing chain kit it should be included with it or look for one that does. I suppose it may have been replaced and that's the original and no harm done.

 

[KELMO]

I have taken apart several "A" motors and agree with Mike's aguessment.

[RyanC]

Yep I would say timing tensioner spring as per the others.

 

Def worth running a coolant flush through her by the looks mine wasn't that bad.  Beware, where you drop it will kill any grass etc ask me how I know thankfully not a big deal for me.  Also I think it needs another after pulling my manifolds again still some sign of gunk but figure once running reguarly it will help clean it.  Use the best coolant you can find.

Edited January 12, 2025 by RyanC

[datsunfreak]

On 1/12/2025 at 5:45 AM, Lachlan said:

Here's how things are looking right now. The timing cover is really stuck on. I'll have to keep massaging it to get it off. I've resisted prying as I don't want to damage the gasket surface and create leaks.

 

IIRS, these go all the way through the cover and into the block. The rust build-up you see around them is probably keeping the cover on. I usually removed these and replace them with bolts.

 

[Dguy210]

15 hours ago, datsunfreak said:

 

IIRS, these go all the way through the cover and into the block. The rust build-up you see around them is probably keeping the cover on. I usually removed these and replace them with bolts.

 

 

Always put some anti-seize on these bolts as a favor for the next guy too...which is often yourself. Been enough times that I had to fix that poor bastards problems it is a rare treat when he thought ahead 😂. 

Edited January 14, 2025 by Dguy210

[Lachlan]

On 1/13/2025 at 12:52 AM, datzenmike said:

My guess is this is from the timing chain tensioner.

 

I'd say you're spot on. When the timing cover was off, I could confirm that the tensioner was doing its job of taking the slack out of the chain, so this errant spring must have been the original.

 

On 1/13/2025 at 9:25 AM, RyanC said:

Def worth running a coolant flush through her by the looks mine wasn't that bad. ... Use the best coolant you can find.

 

Great tip. I watched a ChrisFix video on flushing your cooling system and followed most of the steps. I did have the thermostat installed because I'd put in all the effort of flattening gasket surfaces, sealing half the gasket and greasing the other that I didn't want to remove it again and have it tear.

 

The amount of shmutz that came out was horrid. I did a Tectaloy (local brand) radiator flush followed by at least five demineralised water 'fill - run - drain' flushes. Some included a drive, some included draining the block and the last ones included both. I got to the point where what was coming out was just dirty water with less of the heavier mud component, so I called it good after the fifth.

 

On 1/14/2025 at 12:44 AM, datsunfreak said:

IIRS, these go all the way through the cover and into the block. The rust build-up you see around them is probably keeping the cover on. I usually removed these and replace them with bolts.

 

On 1/14/2025 at 3:47 PM, Dguy210 said:

Always put some anti-seize on these bolts as a favor for the next guy too...which is often yourself. Been enough times that I had to fix that poor bastards problems it is a rare treat when he thought ahead 😂. 

Yeah, and also the little nubs poking out to locate the timing cover / water pump as you send it home. Both had rusted the cover / water pump in position. I gave everything a really good clean and mild polish before reassembly. I didn't go the whole hog and remove the studs and replace with bolts. I can't remember if I applied copper grease or if I just cleaned everything really well.

 

Yeah, you're right - that other guy is usually me going back to fix my earlier work!

[Lachlan]

This is the front side of the timing cover after it was removed. I had a dog of a time getting that front engine seal out.

 

 

Here's the underside with heavy oil deposits that took some scrubbing to remove. I thought I took an after photo but evidently I did not.

 

 

The timing chain also had heavy deposits all over it. The coolant passages were also extremely dirty. I didn't go full tilt cleaning this as I knew there'd be oil in key places that would help when it was started up again. I just carefully cleaned it off the faces of the gears and largely left the chain as is.

 

 

A closer look at the coolant passages behind the water pump. I think this is the inlet.

 

 

And I think this is the outlet leading back to the radiator.

 

 

Here's a shot of it cleaned up a bit more. The cruel irony is that no one will see this.

 

 

And here's it all stitched up again.

 

[Lachlan]

There are no leaks from the timing cover, the water pump, the thermostat housing or even the oil pan. I was sure to have one with the precarious half-moon seals needing a dab of The Right Stuff. I was worried I'd have to get back into this part of the engine again, but I think we're in the clear. They were installed using a method I didn't totally trust but had read about over and over while researching how to do this properly. @datsunfreak even suggested this method when rebuilding the carb. I'm talking about sticking the gasket to the part that can be removed using your favourite sealant and greasing the other side of the gasket for easy removal in the future. Seems to have worked a treat for these!

 

However, the rocker cover has a weep from the rear of the cover. After removing it to set the valve clearances, it seemed no amount of calculated whacking the flanges with a block of wood while balancing the cover over wooden lengths on the underside seemed to help. There's a downward facing lip so you can't just put it on a level surface. I'll give it another go when I inevitably pull it off again to futz around with something else.

 

That leaves the rest of the to do list which is growing like the broom scene in Fantasia. I've pulled on the thread and it just keeps going.

 

Some of them include:

 

- Transmission speedo drive leak. I replaced the seals last year but looks like either I pinched something when reinstalling or there's another problem.

- Flatten the carb top & body mating surfaces and cut a new gasket. Fuel is again leaking out the top of the carb. The float level looks to have risen, so I'm wondering if the float is playing up. I'm getting tired of the Hate-tachi popping it's head up every few months seeking attention.

WEBER THE WORLD!! I think that's how it goes, right?

- Grease the steering column. How on earth do you do that? It's rubbing and making unhappy noises when turning past 9 o'clock (left turns) and 3 o'clock (right turns).

- Remove the pitman arm and realign the steering. I've decided my next purchase will be a gas torch. I'm not messing around with this anymore.

- Push out the dent in the passenger side (vehicle's left side for you guys abroad) which is causing the door to open when the window is wound down. Sometimes I tell people, other times I let them find out.

- Finish painting the panels and get those wheels looking respectable.

 

Of course, there's the smaller things like replacing the diff oil, greasing the rear wheel bearings, wheel alignment, etc but I'll get to those in good time.

 

BUT, there's one thing that's given me pause. Ever since I've got it running and on the road, the car has always made a rattling/knocking/tapping noise from down low in the engine. Only at idle, say below 800 RPM. It disappears the moment you run a fast idle or hit the gas. It's not the valves, it doesn't sound like the chain (nor is it loose) and it doesn't sound like it's coming from the exhaust manifold, even though the exhaust pipe has taken a hit in the past (came to me like that).

 

Adding to this, the Oil light has started to stay illuminated after startup for about 3-4 seconds but then stays off the whole drive. I've never noticed this before but it's now lit up long enough that it caught my attention. I'm worried that my bearings might be cooked from low oil pressure, either by me or prior to me. I have no hard data to go on, only what I've read from other people's posts with similar symptoms.

 

Regarding the oil pressure, I didn't touch anything with the oil pickup when replacing the oil pan gasket and was as careful as I could while manipulating the pan off and on again (multiple times). I haven't touched the oil pump and I don't have an oil pressure gauge installed.

 

What would you do?

[Lachlan]

Here's a video of the noise. Should I be worried?

 

 

[datsunfreak]

On 2/22/2025 at 6:09 AM, Lachlan said:

I haven't touched the oil pump and I don't have an oil pressure gauge installed.

 

What would you do?

 

Install a gauge. Even if it's just temporary. 👍

 

Upside is, replacing the oil pump is a 5 minute job. 

 

Also, these are really just noisy engines. Flat tappets instead of hydraulic, adjustable rockers, timing chain, it all just is noisy (to me).

 

Side question, how many miles since last valve adjustment? 

Edited February 24, 2025 by datsunfreak

[ggzilla]

17 hours ago, datsunfreak said:

these are really just noisy engines. Flat tappets instead of hydraulic, adjustable rockers, timing chain, it all just is noisy (to me).

 

I can't believe you haven't been around a well taken-careof A-series. Properly adjusted there is zero tappet noise. And the timing chain I've never heard one that made any noise. Although come to think of it, it is tricky to get the valve adjustment right ... and if left too long the noise can no longer be adjusted out

 

My two totally stock 1200s were so quiet literally could not hear them idling. But then I adjusted the valves every 12 months (even though the owner's manual says every 6 months). Could do it in about 20 minutes. Best to do with a cold engine on a nice spring day

[datsunfreak]

11 hours ago, ggzilla said:

 

I can't believe you haven't been around a well taken-careof A-series. Properly adjusted there is zero tappet noise. And the timing chain I've never heard one that made any noise.

 

I have been around plenty. But also around plenty of modern OHC timing belt engines that are MUCH quieter. 🙂

 

What do you think that noise it?