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Timing a 4G63 (my "Special" method)

Timing Belt Install – My “Special” Way


This article is good for any timing job but is especially good for those doing the timing job while the motor is still in the car. This was done on a 6 bolt motor, so the write up comes from that particular model. There are many ways to time a 4g63, but I just find this the easiest for me, and usually works on the very 1st try.

I start out by zip tying the belt to the timing gears in place, starting with the exhaust cam, as it normally sits pretty close to on the money already when put into place (Dowels UP and timing marks facing each other). I have a helper (or I can do it myself, it’s just easier to have a 2nd set of hands) zip tie the belt to the intake gear while it is at TDC and the timing marks lined up. Use at least 2 zip ties for each gear, 1 at the top and 1 at the bottom of the gear where the belt is still on it.
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Now I install a new OEM timing tensioner, bolt it down and leave the grenade pin IN.

Next, install the timing tensioner pulley and put the 2 “eyes” for the pulley UP, at the 12 o’clock position (for a 1g) or 7 o’clock (for a 2g) and go ahead and tighten it down so it won’t move.

Next, wrap the timing belt around the tensioner pulley and onto the crank pulley while the crank is at TDC. DO NOT PUT IT AROUND THE OIL PUMP PULLEY YET.

Now take the other side of the belt (the intake side) and pull it STRAIGHT down, do not try to go around the Idler Pulley, yet.
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Double check the timing marks on the cams and at the crank, they should be spot on.

Next, move the oil pump pulley 1 notch clockwise away from its normal timing spot, and gently work the belt onto the oil pump pulley. I have found that easing it on from the very bottom of the pulley and into the pulleys grooves works best as I can rotate the gear left or right slightly to get the teeth to engage.

Now that that is done, grab the timing belt where it is close to the Idler Pulley and pull on it towards the front of the car (or towards the exhaust side of the motor) and coax it over the Idler Pulley. Yes, you can do this with your hands. It will rotate the oil pump gear counter-clockwise slightly when you do this.
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See my picture of where my fingers are, this is where I grab it and pull on it to get it to slide over the Idler Pulley. DO NOT USE A SCREWDRIVER OR ANYTHING OTHER THAN YOUR HANDS.
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Recheck the oil pump for being in time (along with the crank, as it can move but shouldn’t). If the oil pump didn’t end up in the correct spot, pull the belt back off of the Idler Pulley and re-adjust the oil pump gears location and put the belt back on over the Idler Pulley the way I described above. Re-check all timing marks.
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If all went well (and it usually does on the 1st try for me), the crank, oil pump and cam gears will all be lined up and in time (the cam gears CAN’T move so they had better still be lined up). The only thing left for you to do is to pull the grenade pin on the tensioner and see if will slide back in like butter or if you will need to re-tension it slightly at the tensioner pulley that we set at 12 o’clock (for a 1g), or 7 o’clock (for a 2g).

You can now snip the zip ties and test the grenade pin again.
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I go ahead and rotate the motor 6 full turns, until the motor is in time again, cams, crank and oil pump all lined up.
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Check the grenade pin to see if it will slide in and out of its hole. If not, re-adjust the timing tensioner pulley slightly one way or the other. I do use this tool to adjust the tensioner pulley.
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I can usually tell if I need to loosen it or tighten it by feeling how the grenade pin will hit or touch as it tries to go into the back alignment hole.

I also use this tool and thread it into the intake side to hold the timing tensioner in place if I don’t have an extra helper doing this job.
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Here is a picture of a timing job using all of the timing tools instead of using my method, for reference.
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I hope this made the job easier and didn’t confuse anyone. If you have ANY questions about this procedure, just shoot me a PM and I can help. If you find a flaw in these instructions, please let me know so I can correct it!

Thanks,
Marty
 
Last edited:

pauleyman

DSM Wiseman
8,025
2,618
Nov 19, 2011
oklahoma city, Oklahoma
I bet I'm the only one to catch this. Why is the idler bolt not recessed in the last pic? I know the OEM part was superceeded way back when the cars were new. TOTALLY pissed me off the first time I did a tbelt. I had the superceeded pulley but not the bolt. I didn't even think that pulley was made anymore.
 

1990TSIAWDTALON

Moderator
9,147
4,978
Nov 14, 2013
Independence, Kansas
Yeah Paul the 1990 Idler pulley isn't available anymore and I had to use a revised version from STM. I had no idea the long bolt couldn't be used so I didn't order IT. 2 weeks later the bolt comes in........Pissed me off too! I liked the thick Idler much better. It had a "nose" on it and a long bolt.
Oh.....and that isn't my picture. It is one from the vendors website or google, I can't remember so it's not MY engine in that example. Good SPOT!!!! :thumb:
 

1990TSIAWDTALON

Moderator
9,147
4,978
Nov 14, 2013
Independence, Kansas
Just an update. This motor ended up needing the tensioner pulley set at about 12:30.
Here is where it ended up when the grenade pin sides in and out with absolutely no resistance at all.
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sacrileger

Proven Member
262
23
Jun 26, 2016
Orillia, ON_Canada
Just an update. This motor ended up needing the tensioner pulley set at about 12:30.
Here is where it ended up when the grenade pin sides in and out with absolutely no resistance at all.
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what is the significance for the grenade pin to be in the exact position that it can be inserted/removed with ease? perhaps i never got to appreciate the importance of this step. i had used 5/32" drill bit to set the protrusion but then when i removed the grenade pin, sometimes the protrusion ended up being as much as 0.200" and sometimes 0.075"... all depending on the position of the tensioner pulley. i always figured what possible impact could +/- 0.070" protrusion have on the overall setup for as long as the hydraulic tensioner is pushing against the belt and keeping it taut. is that something that makes it more and more important with increasing power output as it appeared to make not much observable difference for my application? i would even think that 0.070" protrusion is better than 0.180" in case the belt stretched.... or the hydraulic tensioner getting weak.
 

1990TSIAWDTALON

Moderator
9,147
4,978
Nov 14, 2013
Independence, Kansas
The belt will never get shorter, so if you set the timing with the pin in, rotate the engine 6 (SIX) times so it ends up in time after rotation (it takes 6 to come back into time) then let it sit about 15 minutes for the tensioner to "settle" its tension and the pin will still slip in and out with ease, then it is good to take up slack as the belt stretches (not that they stretch much, normally they just break). That procedure sits the tensioner deeper in the bore and as you can see on the one you took off that has no pin in it, it will extend about a 1/2" or so (never measured one that was fully extended) out of the body before it has reached the end of its travel. Every 4g63 I have ever built, I timed like this and they all were/are great engines. No mechanical timing issues at all, ever. But I have been building motors since 1978 or so, so I am pretty confident in my rebuilds or timing jobs. I have some 4g63 stuff over on my Youtube channel, check them out and you will see I enjoy building engines.....and racing! :)
https://youtube.com/channel/UCwfCcimqz3w4BSVZ1fthoHQ
Marty
 

sacrileger

Proven Member
262
23
Jun 26, 2016
Orillia, ON_Canada
The belt will never get shorter, so if you set the timing with the pin in, rotate the engine 6 (SIX) times so it ends up in time after rotation (it takes 6 to come back into time) then let it sit about 15 minutes for the tensioner to "settle" its tension and the pin will still slip in and out with ease, then it is good to take up slack as the belt stretches (not that they stretch much, normally they just break). That procedure sits the tensioner deeper in the bore and as you can see on the one you took off that has no pin in it, it will extend about a 1/2" or so (never measured one that was fully extended) out of the body before it has reached the end of its travel. Every 4g63 I have ever built, I timed like this and they all were/are great engines. No mechanical timing issues at all, ever. But I have been building motors since 1978 or so, so I am pretty confident in my rebuilds or timing jobs. I have some 4g63 stuff over on my Youtube channel, check them out and you will see I enjoy building engines.....and racing! :)
https://youtube.com/channel/UCwfCcimqz3w4BSVZ1fthoHQ
Marty
some manuals suggest the protrusion/gap should be b/w 0.150" and 0.180" so i jammed 5/32" drill bit b/w the arm and the body of the tensioner but when i removed the grenade pin, the shaft actually went down (inside the body) because i rotated the tensioner pulley too far and put extra pressure on the belt; and once the belt started pushing back when the grenade pin was out, the gap ended up being 0.070"... i left it that way because i figured that's where the sweet spot was for the upward travel of the hydraulic tensioner shaft and counter tension of the belt. i figured the size of the gap was not that important for as long as the tensioner was engaged.. but i could be wrong.
 

1990TSIAWDTALON

Moderator
9,147
4,978
Nov 14, 2013
Independence, Kansas
As long as the tensioner can "tension" and not be at the end or near the end of its travel, it will do its job but I would not advise anyone to time a 4g any way other than that pin should move free in and out AFTER all adjustments have been made before you pull it for good and are putting the covers back on. Hell I randomly check the motors I have on stands as I walk by, just to see if they have moved and they always slide out and right back in. These are on new rebuilds I have but that doesn't make any difference, it still should be that way to be correct when I build them.
 

sacrileger

Proven Member
262
23
Jun 26, 2016
Orillia, ON_Canada
As long as the tensioner can "tension" and not be at the end or near the end of its travel, it will do its job but I would not advise anyone to time a 4g any way other than that pin should move free in and out AFTER all adjustments have been made before you pull it for good and are putting the covers back on. Hell I randomly check the motors I have on stands as I walk by, just to see if they have moved and they always slide out and right back in. These are on new rebuilds I have but that doesn't make any difference, it still should be that way to be correct when I build them.
i went to measure the gap/protrusion if the pin is in and it appears to be 0.069"... is that what you got as well?
 

1990TSIAWDTALON

Moderator
9,147
4,978
Nov 14, 2013
Independence, Kansas
I don't measure the pin distance and have never measured it, I solely go by the instructions that I wrote up with every 4g motor I build, be it 6 bolt or 7 bolt. When it is in time, all marks align and I can slip a grenade pin into my tensioners with no resistance, it is ready to go in a car. I have 2 motors on stands, built. Those are the ones I randomly put a pin in as I go past them. One will be going into my 90 GSX very soon, I am getting low oil pressure on it and found some metal particles in the oil change pan this last weekend. Glad I have one already built!
 
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