DIY Valve Clearance Shims Adjustment for 4A-GE 20v

9th January 2005

See 4AG 20Valve Engine Repair Manual pages EM-4, 5, 22 & 36. Please also read other pages for more details.


1st thing 1st.

Don't do this by yourself unless you're really confident and have all the necessary skills, knowledge, know-how and most importantly.... FRIENDS and MORAL SUPPORT.

Thanks sifu master yolk @ yoganetram

Thanks master sifu AE80typeD @ Khairul

Thanks kawan kawan sekalian, GT20v @ Zul, Useless @ Bernard, ninja_iga @ Stanley


Sorry to GT20v cannot solve your issue ......

Sorry to Useless cannot discuss the important thing

Sorry to ninja_iga didn't attend to you properly.


You see, there was a unplanned gathering and quite allot of people came and they all wanted a piece of me but in the end I couldn't help them :( so sorry :( my hands were full with my own troubles as you will see below.


Part 1 - Measuring the valves clearance

Intake side, all were on the maximum limit which is 0.30 - surprisingly all same. So................ lazy to change.

Exhaust side. Only measured 4 out of 8 and 3 of them were max thickness 0.50 while one is over limit 0.55

So, taking intake's consistency as confidence and lazy to turn the cam pulley anymore, no strength, I assume all shims that are going to be taken out will need to be thicker by 0.1 mm.

Thanks again to Khairul for pain stakingly helping to write down and record all values ..... and doing the arithmetics. My hands were all dirty :(

Thanks sifu master yolk for bringing back my spare shims with values intact, made life so much easier to find replacement shim of correct thickness. Only 3 were used.

Part 2 - Change shims

After changing the shims by re-shuffling as well as changing from my spares and shuffling some buckets and swapping a bucket from Khairul, the new clearances are: -

valves 1 2 3 4 5 6 7 8

.30 .40 .30 .40 .40 .45 .40 .40

Obviously the 1, 3, is too thin now ...... and the 6 is ngam ngam in between. Perhaps I should redo them ...... wait lah, when do intake will do this again.

manual spec says from 0.4 to 0.5 (mm)

So, not bad lah, for a newbie .... 62.5% are 100% spot on

12.5% is within center of spec

I'd say that makes it 75% passing marks.

25% is out of spec :(


But checking a Mitsubishi MIVEC JUN's performance camshaft it's exhaust only need 0.2 mm gap so my 0.3 mm gap doesn't seem that bad now. So I'll go into lazy mode again and do it later when I redo intake.


Part 3 - Cannot start engine :(

After put back everything...... cannot start. Hahahahha, this is the important story I want to tell ............ crank like long long cannot start. The sound of the engine completely lifeless. I'm not that experience with engines but even I could tell it's not going to start. So, no choice but to check cam positions, ------- aiyah ..... exhaust cam installed wrongly, run-out one whole teeth = advance 10 degrees advance.

since 4ag cam pulley have 36 teeth, so it make 10 degrees per teeth.

I remember Bill Sherwood said when cam pulley run-out one teeth the engine cannot start at all. This was a very important good tips.


OK, since I'm lazy to remove the timing belt again, so I resorted to using the adjustable cam pulley to retard 10 degrees, but still cannot start ....... Wah, so naughty ah the engine, give me allot of troubles ah .... :( OK, try one last trick ....... set distributor free and ask Khairul to crank for me and I keep changing the timing angle until start.

But still cannot start ........... Aiyoh, die lor, all lazy man method failed ....... shxt - how ??? OK, reposition all cam pulleys and check crank angle. Alamak....... run-out to -25 degrees or so.... no wonder the engine cannot start at all lah ......... should be at 0.

So, remove timing belt, turn cam pulleys and crank pulley all into correct position, put back timing belt. Starto. Successful. Can start liao. One click only :) hahahahhha Engine sound different. A bit quiter, A bit smoother. The sound close to Khairul's engine sound. woooo hoooo


When removing the cam all the bolts were removed very slowly, turning no more than 3/4 turn for each position and going through them like 30 times or more. Kia-su.

A torque wrench was borrowed from workshop and the minimum on it's marking is 25Nm, while the manual ask for 17Nm. So, using a best-guess below the mark position and lock all the bolt down. It turn around 1/4 only.

Before that, never force it at all, the slightest of resistance, STOP and turn others until all are resisting same amount then use torque wrench.


By right I should take out the cam and do the 1,3,6 again, but it was late at night and don't have enough time anymore :( This morning took the car out for a drive to LRT station, no faster one??? :( Engine roar also no GARANG :(


BTW, my filler gauge is 0.05 gap, which is not detail enough. Those who are serious for accuracy or performance should use the 0.02 gap type.

I also didn't have proper measuring tools to measure the shims, or buckets or whatever. I only had a vernier caliper and use weird method to measure them all.

Not bad for back-yard boy like me. Can still get 75% 100% correct :) aahaahhahaha


I wonder the next week-end got time to do or not? The other question is that manage to borrow torque wrench or not ??? May be I should go buy one ???


Disclaimer - don't come to me to adjust valve shims, I only did it for fun. It's not worth the trouble to DIY. Lost one whole day only managed half. Not even half considering still need to take out the exhaust cam some other day.

BTW I didn't release the timing belt using the normal method. I simply release the cam pulley and pull it out. So, when installing the cam pulley back, have to pull very hard and align the positions all very correct. Very very difficult.

Stupid me, don't know how to release timing belt tensioner. :(

Don't do this at home. Haih looks like my timing belt is going to break already :( so many scratch marks, pulling pulling, engine oil all over it as well :(


OK lah, I did this because last time crank pulley and cam pulleys oil seals leaking oil, the timing belt was previously all covered with engine oil already. hhahahha that's why this time don't care only. :) ahhahahahhaha lazy chin. So, you see, don't come to me to change valve shims. I'll screw the engine up.


Today. also took the liberty to clean the cam cover inside - so happy now :) as well as clean the K&N air filter using K&N cleaning kit and re-oil kit. The engine breathing sound so cun now :) Previously the filter got stuck allot of engine oil and mud due to last oil seal leak :(




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