Adj Camshaft Pulley & New Cam Belt

[benl1981]

Hey SK - if you take out the starter you could have used a tool to stop the ring gear right? Then just use a 1/2" socket?

Was it hard getting the cam sprockets off and on? I did a timing belt a while ago but there was no signs of leaks so I didn't take the cam sprockets off nor the crank timing gear.

I would be worried when I undo the bolts on the sprocket that the camshaft will move. Did you loosen the 4 bolts on each sprocket before the belt came off? Also did you just use a flat screwdriver to kind of prise the sprocket off or did you use the harmonic balancer for that.

Good thread.

Edited December 10, 2005 by benl1981

[Sydneykid]

Hey SK - if you take out the starter you could have used a tool to stop the ring gear right?  Then just use a 1/2" socket?

Was it hard getting the cam sprockets off and on?  I did a timing belt a while ago but there was no signs of leaks so I didn't take the cam sprockets off nor the crank timing gear. 

I would be worried when I undo the bolts on the sprocket that the camshaft will move.  Did you loosen the 4 bolts on each sprocket before the belt came off?  Also did you just use a flat screwdriver to kind of prise the sprocket off or did you use the harmonic balancer for that.

Good thread.

<{POST_SNAPBACK}>

Yep, but I don't have a ring gear locking tool, and taking the starter motor out of a Stagea is not my idea of fun. Much easier to use a rattle gun.

Exhaust cam shaft pulley came off easy, undo the 4 bolts and tap with plastic hammer. I used a screw driver to hold the pulley while undoing the bolts. Don't worry about the cam rotating, the pulley has a peg, so it only goes on one way. There are marks on the rear cover that you line up (take a look at the posted pictures) to get the camshaft timing right.

cheers

[Sydneykid]

Quick update still at 4 degree retarded, no dyno tuning yet.

cheers

[Tangles]

=(

need that tune!!!!

[Sydneykid]

=(

need that tune!!!!

<{POST_SNAPBACK}>

Yeh Yeh, I hear ya, I just need more hours in the day. I want to fit the magic cat before I get into tuning. Plus I have a 99% completed A/F ratio meter that I want to tune it with before I stick it on the dyno.

Anyone got any hours for sale? I need about 10 extra hours per day for the next 4 weeks.

cheers

PS; Plus we bought an R33GTST last night, that needs some urgent work. I can see the Stagea stuff slipping further down the list.

[3intheBack]

you cant be on the net in daylight hours and getting stuff done on the car at same time...

...oh look at that it's 12.30, lunch time, gotta go.

It's good to be the boss!

[salival]

Hi Sk,

Long time listener, first time caller.. Been following this post for a while and finally did my first cambelt + water pump today on my skidder.. it's not so bad!

have a question about the timing of it, though..

Put everything back into place as to where it was supposed to go re: white dots..

The belt I am using is supplied from my local trade parts place, it's a "mitsuboshi" which I thought was funny.. but it all fits nicely.. the belt has no timing marks on it..

As I said, everything is aligned as to where the dots were supposed to go.. so I assume the timing is at factory timing..

So basically, what i'm wondering is, do I need to set the timing after doing all this.. or will it be "factory"?

Thanks,

Scott.

[lwells]

I had to settle for one of the new duralium HKS pulleys.......

I weighed it (just out of interest) at 350 grams, from memory a standard pulley weighs around 550 grams.

<{POST_SNAPBACK}>

Just out of interest, I put the OS Giken cam I bought on the scale. It weight in at ~324grams including the four locking nuts.

[Sydneykid]

Hi Sk,

Long time listener, first time caller.. Been following this post for a while and finally did my first cambelt + water pump today on my skidder.. it's not so bad!

have a question about the timing of it, though..

Put everything back into place as to where it was supposed to go re: white dots..

The belt I am using is supplied from my local trade parts place, it's a "mitsuboshi" which I thought was funny.. but it all fits nicely.. the belt has no timing marks on it..

As I said, everything is aligned as to where the dots were supposed to go.. so I assume the timing is at factory timing..

So basically, what i'm wondering is, do I need to set the timing after doing all this.. or will it be "factory"?

Thanks,

Scott.

<{POST_SNAPBACK}>

I have found that it always pays to check the ignition timing with a timing light, then you KNOW everyhting is back where it should be, well at least on the exhaust side anyway.

cheers

[YO880]

SK (sorry for bringing up this thread again), i just changed the headgasket and now putting back on teh cams etc. and i am trying to change the timing belt on my RB25DET engine which is currently sitting on the floor (out of the engine bay), I have a manual gearbox attached, new flywheel and clutch etc. but i don't have a drivetrain yet that i can use to stop the flywheel moving

I don't want to shove a bar or similar into the flywheel through the starter motor hole, and similarly, i don't want to take the gearbox off. I can't work out how i can get the bolt out of the harmonic balancer (last one i took out took a LOT of force (again sitting on the floor, trying to keep the flywheel locked with a steel bar)

any ideas on how i can keep the flywheel locked while i try and remove the harmonic balancer? can you buy the ring gear locking tools anywhere (a quick search of the net doesn't show anything)?, i have a no frills air ratchet on a 2HP compressor, but i doubt it has enough force to sneak up on the bolt.

[PJ]

My cam dot doesn't line up on the RHS! I've attached pick of each of the marks, the exhaust side is 2 teeth out of alignment. Had a bit of a look on the net to see if anyone else had the problem. One person said you can rotate the individual cam as long as it was no more that 2 teeth. As far as i know the timing belt had never been changed, got the car when it was on 56k, its now on 99k. The car has never run well, I have always blamed this or that, mechanics have checked it without finding a problem. It uses lots of fuel no matter what I do. (auto, 3" exh, boost 8psi).

Do I rotate the cam, or is there something else I should do?

Any help or insite would be appreciated.

[Bass Junky]

I"m surely no expert, but I'd think you will make a big improvement by turning that Exhaust cam gear back two teeth to where it should be!

[AlexCim]

is that in advance or retard?

If its retard, it could be a good thing as SK has his on 4 degrees retard and it seems to be suitable/good

[3intheBack]

From where I sit the EX looks advanced. The cam is 2 teeth in front of where it supposed to be. So it will be opening too soon while it is still on the power stroke, and shutting too soon before all exhaust gases are expelled.

You definitely need to get it turned back 2 teeth. Every car I have driven with a belt that is one tooth out will run quite smoothly and will have reasonable bottom end (which makes you think that all is OK), but it just wont power on thru the rev range.

I've never done the belt on my RB25 but if it is like any other motor you often have to set them at a point were it looks like they are a tooth out (usually the EX has to go one tooth on the counter clockwise side of the marker) - this will be compensated for when the belt tensioner is applied. The belt tensioner will pull the belt a lot tighter then you can by hand, so the extra stretch between the pulleys will pull them back (read - clockwise) into correct alignment. After you have turned the motor over (at least twice) to feel for any valves hitting the piston crowns and if all is OK then the dots should line up properly. If not then take the belt off, rinse throat with ale and repeat.

...for what's it's worth...

[GoldZilla]

If not then take the belt off, rinse throat with ale and repeat.

...for what's it's worth...

GOLD!!!

[PJ]

Scary stuff this... I can't understand why a stock untouched car would have one of the cams misaligned, surely it would have been picked up when serviced? The only thing I can think of is if the computer covers up the timing problem by compensating for it. I guess in japan it was ok on the 100RON fuel, over here put it over the edge.

Ill turn it one back towards normal and turn the engine through a few cycles.

Edited April 18, 2006 by PJ

[benl1981]

Probably the timing belt was changed in Jap by a bad DIYer or something. Turn the engine by hand to ensure no valve to piston contact.

Edited April 18, 2006 by benl1981

[Sydneykid]

My 20 cents worth;

2 teeth is a lot more than 4 degrees, more like 15 degrees

Check the ignition timing with a timing light, I would be very surprised if it's set correctly (15 degrees advanced). The slot in the CAS usually doesn't allow for 2 teeth out on the pulley.

It is possible for it to jump a tooth (two teeth is a bit unusual) when the cam belt wears. It gets a bit loose and if you get a backwards rotation (sometimes happens at starting) they can jump. How tight is the belt?

Check the bolts holding the pulley to the camshaft, I have seen lose ones cause the belt to slip. Ditto the camshaft tensioner bolt, if it's loose the belt will easily skip.

Look for wear marks on the cam covers, that will tell you if anything else is an issue.

That's about it, personally I would replace the belt, set the camshaft timing and igntion timing correctly and enjoy the power improvement. If you have the budget ($150 or so) think about getting and adjustable camshaft pulley, easy to fit while you are at it.

Hope that was of some help

cheers D

[foznice]

Hey SK, any chance of those pics coming back?

[Sydneykid]

Hey SK, any chance of those pics coming back?

Ask Prank, if he can't do it then I will sit down and change the links myself, one by one. I am getting a bit tired of emailing pictures to people.

cheers