3K-U Mechanical advancing

[TharinduR]

Hello, 

I have a Corolla KE50 with a 3K-U engine. The fuel economy is not very good from the day we bought it, around 20 years now  its around 10-13max on long distance.

Initially it was converted to LPG and most of the vacuum lines and stuff were stripped off. Now only I'm going through everything and trying to restore it. I have rebuilt the carby with a repair kit as the mechanics here have messed up the jets and everything, the only available repair kit is 3k ones. (can't find any 3k-U) 

I have tried various methods with carburetor by reducing jet sizes, adjusting float levels etc... but hasn't improved anything.

Then the electrical system, the original ignitor unit was available and not working, after some searching managed to get it working again and now the ignitor unit is working. Yet no major improvements, but engine runs smoother and able to idle around 650RPM smoothly.

When keep reading about these things, many articles form this form too I got a feeling that advancing may have to do something with the economy of the engine because any other method didn't work out. Mainly the advancing curve, because the original distributer this car had was rusted and we replaced with a aftermarket one for 3K engine. 

The vacuum advance was way off it went for around 70*+ I think where it should be around 52*. So Changed the vacuum advancer and managed to sort it, it works on the range 1500-2500.

The issue is mechanical advancing does not work on that range. It starts around 3000RPM and goes for about 4500 to get max advance. Which I think is too much?

Can any one guide me to correct this, where I can find springs or how I can adjust the tension. And if my values are incorrect what should have happen, I'm a IT person so only know what I read about mechanics.  So please excuse me if I'm on the wrong idea or I have done anything wrong. 

Thank you in advance. 

[altezzaclub]

Take a look through here, I fitted an electronic dizzy and found the advance curve to be very late.  In the end I used springs I found around the house to make it work.

https://www.rollaclub.com/board/topic/42407-the-girls-ke70/page/4/

https://www.rollaclub.com/board/topic/49927-how-to-fix-your-brand-new-ke-motorsport-electronic-distributor/#comment-511594

 

[parrot]

is it still running on LPG?

[TharinduR]

46 minutes ago, parrot said:

is it still running on LPG?

No Now its running on Gasoline. LPG is costly now, and I recall even with LPG it didn't have much mileage.

[TharinduR]

6 hours ago, altezzaclub said:

Take a look through here, I fitted an electronic dizzy and found the advance curve to be very late.  In the end I used springs I found around the house to make it work.

https://www.rollaclub.com/board/topic/42407-the-girls-ke70/page/4/

https://www.rollaclub.com/board/topic/49927-how-to-fix-your-brand-new-ke-motorsport-electronic-distributor/#comment-511594

 

 

This information is very helpful, thank you very much for taking time to document it. And keep the good work going.

[parrot]

Surely you can source a replacement original fitment Carb and distributor locally. I think you are going to be chasing your tail forever and need to revert to stock fittings. I expect you know that the U designation relates to emissions. So while the various vacuum lines are superfluous, it may not be happy if you get them wrong. 

[Banjo]

I've never ever physically come across a 3K-U engine, here in Australia, although owning & running a 4K-U, which was a very good engine, producing a bit more power, standard; than the more common 4K-C.  I had to look up the net, to see what officially the 3K-U was built for.  Like Pete says, it appears to meet local Japanese emissions requirements.

The word "catalyst" may indicate, it had some sort of cataytic converter in the exhaust system, to clean the exhaust gases a bit.

Unless it had a slightly different camshaft timing, I can't image that putting it back to a standard carby & standard dizzy, would not bring it back to normal power output. However, as we have found previously, on this forum; when an engine series is so olde, there couuld well be an issue at some time in it's life, where it has been reassembled with the timing chain out a link or something. I seem to remember way back; someone shearing off the locating pin between camshaft & chain sprocket, & it creating an issue, like you describe.

Cheers

Banjo

 

 

[TharinduR]

On 2/11/2024 at 4:10 AM, parrot said:

Surely you can source a replacement original fitment Carb and distributor locally. I think you are going to be chasing your tail forever and need to revert to stock fittings. I expect you know that the U designation relates to emissions. So while the various vacuum lines are superfluous, it may not be happy if you get them wrong. 

The distributors here are most of the time either very old or they lack parts, so that is why I got a new one from a shop here,  Yes you are correct, Its the emission type and it has many vacuum controlled valves and things that are not there any more. Here if the mechanics doesn't understand what the part is for, its not necessary for the engine so they remove it ha ha. That's what happen to this car also, most of the things are not there.

I'm from Sri Lanka and most now doesn't care about the old cars here now if they are running that's it.

 

On 2/12/2024 at 7:14 AM, Banjo said:

I've never ever physically come across a 3K-U engine, here in Australia, although owning & running a 4K-U, which was a very good engine, producing a bit more power, standard; than the more common 4K-C.  I had to look up the net, to see what officially the 3K-U was built for.  Like Pete says, it appears to meet local Japanese emissions requirements.

The word "catalyst" may indicate, it had some sort of cataytic converter in the exhaust system, to clean the exhaust gases a bit.

Unless it had a slightly different camshaft timing, I can't image that putting it back to a standard carby & standard dizzy, would not bring it back to normal power output. However, as we have found previously, on this forum; when an engine series is so olde, there couuld well be an issue at some time in it's life, where it has been reassembled with the timing chain out a link or something. I seem to remember way back; someone shearing off the locating pin between camshaft & chain sprocket, & it creating an issue, like you describe.

Cheers

Banjo

 

 

 

Thank you very much Banjo you are correct, it seems to have had a catalytic converter and its not there any more, also there was a air pump that pumps fresh air to the exhaust, which we managed to get working and unfortunately broke because water from exhaust came to the pump and rusted it because we didn't know about the one way valve that should be there, (the pump was never used and we tried it so parts were missing)

This engine has several Manuals it seems 3K-U manual is a separate one and very hard to find. I will check your suggestion checking the timing chain too. I'm just digging and doing these things for my knowledge and as a hobby, so thank you all for your shareings

[parrot]

The airpump is part of the emissions so you don't need that, or the cat con.

Cut your losses and put a non pollution engine in it.

These guys have a KE55 listed on facebook right now.

Gamage Motors

Corolla ke 55 parts available

0773180126

Galle

[TharinduR]

I have taken the distributor out and will try altezzaclub's spring changing methods, Lets see how it goes.

I will keep things updated here in case some one else also tries to do same thing.

[Banjo]

There is a pretty easy way to check the camshaft timing, without removing the timing chain cover; which is a bit hard to do, with the engine installed. Remove all the spark plugs, & the oil filler cap, & the dissy HT cover.

Place a mark on the dissy aluminum base edge, where no: 1 spark plug lead connects to the spark plug.  Rotate the engine until the crankshaft pulley "timing mark" lines up with the corresponding mark, on the timing chain cover.  If the dissy rotor is out 180 degrees, then rotate the crankshaft an extra full turn, until the timing marks aligned, again.

This should be T.D.C. No: 1 cylinder.  Place a long screwdriver down no: 1 spark plug hole, & rock the crankshaft back & forth, to confirm that the piston, is right at the top of the travel.  If it is, then your camshaft timing, is probably all good.  There are a couple of things that could be amiss, if it is not at TDC, that may not be a result of a camshaft chain alignment being an issue.  eg:  The engine at sometime in it's life has had a timing chain cover, or a crankshaft pulley fitted, that originally came from a 5K engine, which had the marks in slightly different positions. Once you have determined that the no: 1 piston, is at TDC, you can rock the crankshaft back & forth, & looking down the oil filler hole, you should see that both inlet & exhaust rocket arms are clear of the valves. A penlite torch, often assists with this test, or alternatively remove the rocker cover. 

When you have determined everything is OK, then turn the crankshaft, "anti-clockwise", until the timing mark on the pulley lines up with 10 -12 deg. BTDC.   Now check that the arc on the dissy rotor, is still pointing towards no: 1 spark plug lead position. If not, then there is always the possibility, that the dissy has been inserted into the block, 1 tooth out.

I hope this all proves out there is not an inherent assembly problem, & then, you can concentrate on getting the centrifugal & vacuum advance / retard settings sorted.

Let us know how you go.  

Cheers Banjo

Edited February 16, 2024 by Banjo

[TharinduR]

10 hours ago, Banjo said:

There is a pretty easy way to check the camshaft timing, without removing the timing chain cover; which is a bit hard to do, with the engine installed. Remove all the spark plugs, & the oil filler cap, & the dissy HT cover.

Place a mark on the dissy aluminum base edge, where no: 1 spark plug lead connects to the spark plug.  Rotate the engine until the crankshaft pulley "timing mark" lines up with the corresponding mark, on the timing chain cover.  If the dissy rotor is out 180 degrees, then rotate the crankshaft an extra full turn, until the timing marks aligned, again.

This should be T.D.C. No: 1 cylinder.  Place a long screwdriver down no: 1 spark plug hole, & rock the crankshaft back & forth, to confirm that the piston, is right at the top of the travel.  If it is, then your camshaft timing, is probably all good.  There are a couple of things that could be amiss, if it is not at TDC, that may not be a result of a camshaft chain alignment being an issue.  eg:  The engine at sometime in it's life has had a timing chain cover, or a crankshaft pulley fitted, that originally came from a 5K engine, which had the marks in slightly different positions. Once you have determined that the no: 1 piston, is at TDC, you can rock the crankshaft back & forth, & looking down the oil filler hole, you should see that both inlet & exhaust rocket arms are clear of the valves. A penlite torch, often assists with this test, or alternatively remove the rocker cover. 

When you have determined everything is OK, then turn the crankshaft, "anti-clockwise", until the timing mark on the pulley lines up with 10 -12 deg. BTDC.   Now check that the arc on the dissy rotor, is still pointing towards no: 1 spark plug lead position. If not, then there is always the possibility, that the dissy has been inserted into the block, 1 tooth out.

I hope this all proves out there is not an inherent assembly problem, & then, you can concentrate on getting the centrifugal & vacuum advance / retard settings sorted.

Let us know how you go.  

Cheers Banjo

 

Thank you very much for the very informative reply Banjo, I have already tested this, It seems OK, the pistons and timing mark aligns up nicely.

The only issue I'm facing is low mileage, except that engine doesn't misfire, I have set the base timing to 8* as the manual says and the 8* mark is also there in cover.

Current centrifugal advancing starts around 3000 RPM, and maxes out around 4500 I think, so that is why I'm checking how to change it. 

Vacuum advancing was off too, it went for around 60-70* on 3000 RPM which is way off. So I checked with another dizzy and found out my advance is advancing too much. And now using a different advance for now until I correct my one. (Its advancing length is long that's the issue.)

 

[TharinduR]

Update: I updated the springs with lighter ones and got the curve around 2000 - 4000 advancing and It made some improvement.

Today I changed one of the springs to a lighter one and now the curve is around 1500 - 2500. I will gave a spin and update. I think that is a better curve rite?

 

I had another issue, my 1-4 plugs are black and 2-3 plugs are perfect, Any reason for this? I'm trying the distributor changes without the vacuum advance. This issue was there before I change the springs also.

Thank you for valuable ideas and guidance from this forum.

[altezzaclub]

Yes, that's a much better advance curve, you should have the whole 36deg on by 3500rpm. The K motors will take more advance than that, its just a matter of what fuel you can buy and how much advance you can give it before it starts to lose power or knock.

The plug colours are interesting, I don't know why they are in piston pairs like that. I wonder if 2 and 3 have an inlet air leak around the exhaust port in the middle and are running lean? Check the bolt tightness along the manifolds just in case.

Is there one of those air pump/pollution lines run into the inlet manifold in the middle?

Otherwise it is a richness problem with 1 and 4, even harder to explain! maybe a misfire on 1 and 4 is making them black.

[TharinduR]

Thank you for reply altezzaclub. 

I think it goes to around 52deg or something, in the K manual also total advance is mentioned around that I think. Anyway had a spin today and It was really good, no knocks good pickup, and smooth acceleration. Earlier I had to struggle to overtake since it took some time to spin-up the engine, now I can overtake smoothly. Have to check if the fuel economy has improved, I will update here.

I checked all around about the plug colors and its a mysterious case didn't found any other incidents like this on the net. I have checked the wires, contacts, switched the plugs, doublechecked the gaps, I guess it has something to do with advancing also, since earlier all 4 plugs were good. Also I have to check valve clearances, I checked the compression and its very low, around 106psi-108psi per cylinder, and 1-4 are on 106psi so there maybe something to do with that too. 

Since there's no missing and engine runs smoothly at around 650RPM I don't think it has to do anything with timing, I will check and post with the findings.
Everything for pollution control system has been disconnected and air-pump doesn't work anymore so its removed.