KE30 3K TO 4K SWAP

[HaqimShah]

Hello everyone, I'm new here. Recently i just swapped my 3K-H to a 4K-C engine with oversized piston, 5K carbs, 5K starters, 5K distributors. Engine was fully rebuilt by a mechanic whom i paid to do those job. It has been a month ever since i swapped the engine but i still can't drive the car due to the constant jerking when moving. Sometimes the engine died whenever i change gears. Really in need of help since ive been putting so much time and money to get this car fixed!

[Banjo]

Welcome aboard !  Sounds like You had the 4K-C engine done professionally, but the car is not drivable.

If You could take a few pictures in your engine bay, it would help us envisage, what You are dealing with.

Better still, would be a video, with sound, so we can hear the engine running.

The intermittent nature of the engine, could be ignition time; or air fuel ratio, or a combination of both.

Does the engine have one (1) off 5K carby, or two (2) off ?

Is the 5K distributor an electronic one, with no points ?

Does the engine idle all right, & the problem occurs only, when You are driving it, with a load on it ?

I'm presuming You put new spark plugs in it, after the rebuild.  Have you removed the plugs to see what colour the internal insulator is ?

Have you or someone else checked the valve & ignition timing, which is best carried out, with the rocker cover removed, so you can watch the valve rockers actions.

Send us some pics, & a video, & we'll see if we can't provide some concrete suggestions.

P.S.  Where are you located ?

Cheers Banjo

[altezzaclub]

Can you fit your old dizzy, your old fuel pump and your old carb?? Not all at once, one at a time and see if one of them fixes it.

Otherwise, could be fuel starvation, or timing, it really depends on when it jerks. 

 

On over-run??  On acceleration?  Going up a hill? On a tiny amount of throttle?? Does it idle smoothly?

[HaqimShah]

19 hours ago, Banjo said:

Welcome aboard !  Sounds like You had the 4K-C engine done professionally, but the car is not drivable.

If You could take a few pictures in your engine bay, it would help us envisage, what You are dealing with.

Better still, would be a video, with sound, so we can hear the engine running.

The intermittent nature of the engine, could be ignition time; or air fuel ratio, or a combination of both.

Does the engine have one (1) off 5K carby, or two (2) off ?

Is the 5K distributor an electronic one, with no points ?

Does the engine idle all right, & the problem occurs only, when You are driving it, with a load on it ?

I'm presuming You put new spark plugs in it, after the rebuild.  Have you removed the plugs to see what colour the internal insulator is ?

Have you or someone else checked the valve & ignition timing, which is best carried out, with the rocker cover removed, so you can watch the valve rockers actions.

Send us some pics, & a video, & we'll see if we can't provide some concrete suggestions.

P.S.  Where are you located ?

Cheers Banjo

Thanks for the reply Banjo! I don't really know how to upload the video here, by any chance is there any other way for me to contact you? My instagram’s @/juoone btw! The engine have 1 off 5K carby. Original distributor ( non electrical, but i just ordered the electrical distributor last night hehe ). Idle is fantastic, sounds good for me. The problem occur whenever i start to pick up some speed. It jerks all the time. The plug’s insulator color is yellowish burnt. I’m planning on getting someone to come and check it for me tho! Still don’t have the time since I'm quite busy with school still hahaha! I’m from Brunei Darussalam btw, a tiny country based in south east asia 🇧🇳

 

ps: don't mind the messy engine bay haha

[HaqimShah]

16 hours ago, altezzaclub said:

Can you fit your old dizzy, your old fuel pump and your old carb?? Not all at once, one at a time and see if one of them fixes it.

Otherwise, could be fuel starvation, or timing, it really depends on when it jerks. 

 

On over-run??  On acceleration?  Going up a hill? On a tiny amount of throttle?? Does it idle smoothly?

Old dizzy’s pin wiggles already. Fuel pump is all good, good fuel flow from the carby as well and ive tried using the old carby, still the same problem. It jerks whenever i pickup some speed and yes it idles smoothly

[altezzaclub]

In that case, check the dizzy and timing. The dizzy pin in the center should wind back a little and spring forward again if you turn the rotor, that's the springs under the base plate controlling the advance. You could take the base plate out, its only two screws, and examine the weights and springs underneath. They are what advances the ignition as you accelerate.  If the pin moves sideways, yes its a very worn bush at the bottom of the dizzy, and that can change the points gap and timing all the time.

You may find the new dizzy has a terrible advance curve due to the springs they use, as per a recent post on here in the last week or two. The electronic dizzys are for a fork-hoist or a van, so make the car very slow.

Coil is another suspect, they can idle OK but break down when under pressure as you accelerate causing a misfire.

Its not pinkng is it, that light detonation under acceleration that is caused by too much advance  and each misfire causes a knocking sound? I haven't heard it in decades now every car is computer controlled. Try  higher octane petrol once your tank is nearly empty, maybe 97octane Premium won't do it.

Do you have a timing light, a very handy tool that is worth buying for all the vehicles you will own?

[HaqimShah]

50 minutes ago, altezzaclub said:

In that case, check the dizzy and timing. The dizzy pin in the center should wind back a little and spring forward again if you turn the rotor, that's the springs under the base plate controlling the advance. You could take the base plate out, its only two screws, and examine the weights and springs underneath. They are what advances the ignition as you accelerate.  If the pin moves sideways, yes its a very worn bush at the bottom of the dizzy, and that can change the points gap and timing all the time.

You may find the new dizzy has a terrible advance curve due to the springs they use, as per a recent post on here in the last week or two. The electronic dizzys are for a fork-hoist or a van, so make the car very slow.

Coil is another suspect, they can idle OK but break down when under pressure as you accelerate causing a misfire.

Its not pinkng is it, that light detonation under acceleration that is caused by too much advance  and each misfire causes a knocking sound? I haven't heard it in decades now every car is computer controlled. Try  higher octane petrol once your tank is nearly empty, maybe 97octane Premium won't do it.

Do you have a timing light, a very handy tool that is worth buying for all the vehicles you will own?

Thanks for the reply, guess i should’ve stayed with the original distributors 😭.

i recently payed someone to inspect the car and one of them said that he’s 100% sure that it’s a valve problem. I don’t really know how and why since i just started to get into cars after the KE30 was handed down to me by my grandpa haha

[Banjo]

I've read your post through again today, & I must say, that the engine bay looks very clean & neat.

I hear you say it idles perfectly, but when you increase revs, it "jerks", under load.

I'm going to have a stab at this; based on a similar problem, I came across, a few years ago. 

As soon as you increase revs, & load; with your foot hard on the accelerator pedal, the fuel consumption increases, & the carby bulb lowers, & the valve opens to input more fuel. If the fuel pump is not up to it, then you could easily obtain the "jerky" engine response.  

Did you fit a new fuel pump, of is it the original ?  The mechanical fuel pumps on the K series engines, are usually very reliable. When olde, they are known to suffer deterioration of the  main rubber diaphragm.  The tiny spring loaded valves, can sometimes get dirt in then, or break.   However, there are two things that can prevent the fuel pump not being able to produce output.  The first one, is if the fuel pump, is attached to the block, without the "fiber" spacer, between the pump & block mounting flange.  This is rare, but I have come across it on one or two occasions; although it usually destroys the pump pretty quickly.  The second problem with low fuel throughput, is the pump being mechanical, has to be mounted on the engine.  However, that results in the suction path from the fuel tank, to the pump inlet being long.  I have found that even if the pump is working perfectly, that they don't work very well, if there is the tiniest leak in the long inlet line, & it sucks air in. On many olde Corollas, there is a rubber joiner in the fuel pump inlet line, under the floor pan, & this goes hard & brittle, & can cause, the issue you describe.  Ideally, the fuel pump can be electrical, & sited close to the tank, so that the suction section of pipe to the electric pump inlet is short; & the line to the carby is always under pressure.  Only real issue with electric pumps, is that You must include a "safety cut-out", for the electric pump, if the vehicle is ever in an accident.

Cheers Banjo

Edited February 25 by Banjo

[HaqimShah]

1 hour ago, Banjo said:

I've read your post through again today, & I must say, that the engine bay looks very clean & neat.

I hear you say it idles perfectly, but when you increase revs, it "jerks", under load.

I'm going to have a stab at this; based on a similar problem, I came across, a few years ago. 

As soon as you increase revs, & load; with your foot hard on the accelerator pedal, the fuel consumption increases, & the carby bulb lowers, & the valve opens to input more fuel. If the fuel pump is not up to it, then you could easily obtain the "jerky" engine response.  

Did you fit a new fuel pump, of is it the original ?  The mechanical fuel pumps on the K series engines, are usually very reliable. When olde, they are known to suffer deterioration of the  main rubber diaphragm.  The tiny spring loaded valves, can sometimes get dirt in then, or break.   However, there are two things that can prevent the fuel pump not being able to produce output.  The first one, is if the fuel pump, is attached to the block, without the "fiber" spacer, between the pump & block mounting flange.  This is rare, but I have come across it on one or two occasions; although it usually destroys the pump pretty quickly.  The second problem with low fuel throughput, is the pump being mechanical, has to be mounted on the engine.  However, that results in the suction path from the fuel tank, to the pump inlet being long.  I have found that even if the pump is working perfectly, that they don't work very well, if there is the tiniest leak in the long inlet line, & it sucks air in. On many olde Corollas, there is a rubber joiner in the fuel pump inlet line, under the floor pan, & this goes hard & brittle, & can cause, the issue you describe.  Ideally, the fuel pump can be electrical, & sited close to the tank, so that the section of pipe to the electric pump inlet is short; & the line to the carby is always under pressure.  Only real issue with electric pumps, is that You must include a "safety cut-out", for the electric pump, if the vehicle is ever in an accident.

Cheers Banjo

Thanks for the reply Banjo! 
 

the fuel pump I'm currently using is the one originally from the 4K-C engine. I’m not quite sure if it has no faulty or whatsoever. I might try swap it with a different fuel pump. Maybe from my 3K engine since i am pretty sure that the previous one works well. Once again thanks for the suggestion. Will reply to you once i have the results 🤝🏻

[Banjo]

Electric fuel pumps are very reliable, & for this application, of a carby engine, are not expensive, unlike the high pressure pumps required for EFI applications, which are costly.

I've got one on my "test bed carby 5K engine", on a stand in my garage, & it works very well.  Here is a common one on ebay.

Most of them are about 3-6 psi output, & run on 12Vdc.

Cheers Banjo