Discussion
blk86esprit said:
I spent over 3 hours last night trying to get all the timing marks to perfectly line-up. Every time I adjust the belt tension the cams are off about 1/2 tooth, or crankshaft is off about 5 deg.
Any help appreciated.
Larry
Hi,
You can really only be off in full tooth increments. One thing which can help would be to put the car in gear and let the clutch hold the crank in place. Also, you can use some spring clamps to hold the timing belt onto the Cams. This way, there is no slipping as you tension the belt and it ends up on the proper teeth.
Very Important - Make sure that once you are properly tentioned that you rotate the crank by hand two full revolutions to be sure the belt doesn't slip or walk on the pulleys. If you don't, you may throw the belt, especially when under the extreme torque of the starter motor and then bad things are really gonna happen. Happy Motoring! ...Jim'85TE
Speaking of timing belts, I have never tried this, but it was suggested by another wrencher in another world some time ago:
Split the old belt lengthwise so a thin portion remains on the pulleys, like 1/2 or so. Slip the new belt on all the pulleys so it is half on with the existing half belt still there. Cut the old belt off completely, push the new belt all the way on. New belt now is on and the pulleys have not changed in relation to each other.
Whaddya think Jim?
Dr.Hess
Split the old belt lengthwise so a thin portion remains on the pulleys, like 1/2 or so. Slip the new belt on all the pulleys so it is half on with the existing half belt still there. Cut the old belt off completely, push the new belt all the way on. New belt now is on and the pulleys have not changed in relation to each other.
Whaddya think Jim?
Dr.Hess
Thanks for the quick input!!
I've had the belt on and off at least a dozen times, but it is always the same. I even put wire ties on the three gears, but they still were able to move just a bit when I tensioned the belt. It is only off on the cam gears about 1/2 a tooth when crank is at TDC. The intake gear seems to be the one that won't line-up, retarded the 1/2 tooth space. With the gears alligned the crank is about 5 deg. past TDC. If you believe this to be OK I'll go ahead and put it all back together.
Are there any considerations I should be aware of with the distributor gear? I recall someone having problems with not having enough the spark advance travel with the distributor.
Thanks,
Larry
I've had the belt on and off at least a dozen times, but it is always the same. I even put wire ties on the three gears, but they still were able to move just a bit when I tensioned the belt. It is only off on the cam gears about 1/2 a tooth when crank is at TDC. The intake gear seems to be the one that won't line-up, retarded the 1/2 tooth space. With the gears alligned the crank is about 5 deg. past TDC. If you believe this to be OK I'll go ahead and put it all back together.
Are there any considerations I should be aware of with the distributor gear? I recall someone having problems with not having enough the spark advance travel with the distributor.
Thanks,
Larry
Larry,
It is also possible that the marks on the pulleys are not correct or the timing marks on the crank are not correct. What I would do if I were in your place is to actually degree in the cams. That is, you put a degree wheel on the crank, find true TDC with a dial indicator, find the opening/closing points of the valves with the dial indicator and use that to determine if you need to be +1/2 or -1/2 tooth. At very least, find true TDC and confirm that the crank reads TDC as well. To do this, bring the motor to just before TDC with your indicator down the spark plug hole (there are adatpers, or you can make one from an old spark plug), bring #1 up to a point where the dial indicator shows it to be some point before TDC, like 50 thou or whatever, mark the crank position, move the crank through tdc to a point that is the same measurement after TDC (50 thou in our example), mark the crank. True TDC is halfway between the 2 marks. See where that lines up with what your OEM marks show.
Yeah, it is going to be a PITA, but then, what isn't?
Dr.Hess
It is also possible that the marks on the pulleys are not correct or the timing marks on the crank are not correct. What I would do if I were in your place is to actually degree in the cams. That is, you put a degree wheel on the crank, find true TDC with a dial indicator, find the opening/closing points of the valves with the dial indicator and use that to determine if you need to be +1/2 or -1/2 tooth. At very least, find true TDC and confirm that the crank reads TDC as well. To do this, bring the motor to just before TDC with your indicator down the spark plug hole (there are adatpers, or you can make one from an old spark plug), bring #1 up to a point where the dial indicator shows it to be some point before TDC, like 50 thou or whatever, mark the crank position, move the crank through tdc to a point that is the same measurement after TDC (50 thou in our example), mark the crank. True TDC is halfway between the 2 marks. See where that lines up with what your OEM marks show.
Yeah, it is going to be a PITA, but then, what isn't?
Dr.Hess
Dr Hess,
I did check TDC with an indicator. The mark on the flywheel is real close, almost exactly lined up with the pointer. The engine is in the car, so I can't really do a proper check with the degree wheel I have. It is about 12" dia. no room in those close quarters of an Esprit!!
I'm going to try it once again tonight. Wish me luck!
Larry
I did check TDC with an indicator. The mark on the flywheel is real close, almost exactly lined up with the pointer. The engine is in the car, so I can't really do a proper check with the degree wheel I have. It is about 12" dia. no room in those close quarters of an Esprit!!
I'm going to try it once again tonight. Wish me luck!
Larry
Is it possible that your head was milled at some point? That could throw the timing off, but I don't know if it would do 1/2 tooth. I think you are going to have to degree it, even if it comes to taking the front pulley and carefully marking it every 5 degrees or whatever, then spinning it and seeing where the valves are actually opening.
Dr.Hess
Dr.Hess
I don't know if the head or block had been milled in the past.
I just spent another couple hours re-checking everything, still can't line it all up. I'm going to try retarding both cams slightly and see if I can bring them in when I tension the belt.
Another thing I've found is there are several dots on the aux gear. I've been using the one nearest the IN mark, this lines-up the rotor with the cap post just before the notch it the distributor cap. Is this the way it is made to line-up for cyl #1 timing?
By the way, the cam dots were only a little off when I took the old belt off and I also marked the aux gear.
Larry
I just spent another couple hours re-checking everything, still can't line it all up. I'm going to try retarding both cams slightly and see if I can bring them in when I tension the belt.
Another thing I've found is there are several dots on the aux gear. I've been using the one nearest the IN mark, this lines-up the rotor with the cap post just before the notch it the distributor cap. Is this the way it is made to line-up for cyl #1 timing?
By the way, the cam dots were only a little off when I took the old belt off and I also marked the aux gear.
Larry
I had the same problem with my 91 SE.
The way I fixed this was to back the crank pully up just about one tooth then put the belt on. You will have slight slack on the oppsite side of the tensioner, when you tension the the belt, it will move the crank just about 1 tooth, and take up all the slack. I blocked the cam pulleys so they would not move(two blocks of wood and 'c'clamps)I always do this on DOHC motors as the exhaust cam tends to walk. You will be amazed how easy it will be to line up the dots this way.
The way I fixed this was to back the crank pully up just about one tooth then put the belt on. You will have slight slack on the oppsite side of the tensioner, when you tension the the belt, it will move the crank just about 1 tooth, and take up all the slack. I blocked the cam pulleys so they would not move(two blocks of wood and 'c'clamps)I always do this on DOHC motors as the exhaust cam tends to walk. You will be amazed how easy it will be to line up the dots this way.
blk86esprit said:
I don't know if the head or block had been milled in the past.
I just spent another couple hours re-checking everything, still can't line it all up. I'm going to try retarding both cams slightly and see if I can bring them in when I tension the belt.
Another thing I've found is there are several dots on the aux gear. I've been using the one nearest the IN mark, this lines-up the rotor with the cap post just before the notch it the distributor cap. Is this the way it is made to line-up for cyl #1 timing?
By the way, the cam dots were only a little off when I took the old belt off and I also marked the aux gear.
Larry
Larry,
Be sure that all the slack is between the Ex Pulley and the Crank Pulley. Be sure that the gearbox is engaged to 'hold' the crank. Then, slowly bring the tensioner taut to spec.
So far as the distributor is concerned, the Aux. shaft mark is somewhat arbitrary in that you get the rotor arm to rest just before any lug on the dist. cap, use this lug for your #1 plug wire (remember firing order 1*3*4*2), but also be certain that you have enough free swing in the distr. body to get to your desired static timig before hitting the Vac. Adv. module or the Int. Manifold.
With a new (unstretched) belt, it isn't unusual for the timing marks to be slightly off. If this is the case, better to retard them and allow the stretching of the belt to advance them back to spec.
Remember, the proper procedure has you running the belt for at least two minutes or until warm-up. This allows all the slack to homologate throughout the run of the belt and allows for some stretching. You are to retension as necessary after this initial run-up. Happy Motoring! ...Jim'85TE
Jim
I’ve a question for you with reference to the 2 mins run you mentioned.
I recently changed the belt whilst I had the engine out, I’ve never done one on a Esprit before. I tensioned up correctly (with gauge), rotated the engine a couple of times and re-checked, all appeard fine and the engine went back in a few weeks later.
Back in the car and it ran through a couple of heat cycles once each weekend for a couple of weeks. I then noticed the belt was significantly slacker than when I fitted it, it was audible 'slapping about' between the inlet and aux pulleys when I reved it up.
I re-tensioned the belt but I’ve been a little worried that I might have over tensioned a belt that had stretched. What do you think?
The car has just been moving around the body shop since, its not been on the road.
Gareth 89 SE.
I’ve a question for you with reference to the 2 mins run you mentioned.
I recently changed the belt whilst I had the engine out, I’ve never done one on a Esprit before. I tensioned up correctly (with gauge), rotated the engine a couple of times and re-checked, all appeard fine and the engine went back in a few weeks later.
Back in the car and it ran through a couple of heat cycles once each weekend for a couple of weeks. I then noticed the belt was significantly slacker than when I fitted it, it was audible 'slapping about' between the inlet and aux pulleys when I reved it up.
I re-tensioned the belt but I’ve been a little worried that I might have over tensioned a belt that had stretched. What do you think?
The car has just been moving around the body shop since, its not been on the road.
Gareth 89 SE.
Success at long last!!!
Thanks to all who shared their knowlege, it is greatly appreciated.
BTW, what seemed to work was allowing for a bit of movement between the different gears and while tensioning the belt all fell into place nicely.
New few questions about tension.
I have the KR1. There are two scales, top scale in KG bot scale in LBS. Belt is at 55-60 LBS now.
1 What is the correct scale and amount?
2 Is there a range to be in?
Thanks again,
Larry
Thanks to all who shared their knowlege, it is greatly appreciated.
BTW, what seemed to work was allowing for a bit of movement between the different gears and while tensioning the belt all fell into place nicely.
New few questions about tension.
I have the KR1. There are two scales, top scale in KG bot scale in LBS. Belt is at 55-60 LBS now.
1 What is the correct scale and amount?
2 Is there a range to be in?
Thanks again,
Larry
igreenrover said:
Jim
I’ve a question for you with reference to the 2 mins run you mentioned.
I recently changed the belt whilst I had the engine out, I’ve never done one on a Esprit before. I tensioned up correctly (with gauge), rotated the engine a couple of times and re-checked, all appeard fine and the engine went back in a few weeks later.
Back in the car and it ran through a couple of heat cycles once each weekend for a couple of weeks. I then noticed the belt was significantly slacker than when I fitted it, it was audible 'slapping about' between the inlet and aux pulleys when I reved it up.
I re-tensioned the belt but I’ve been a little worried that I might have over tensioned a belt that had stretched. What do you think?
The car has just been moving around the body shop since, its not been on the road.
Gareth 89 SE.
Gareth,
The tension spec is the tension spec. This would be for a used or new belt. So, when you retensioned it, if you tightened it to the specified amount, you're ok. Happy Motoring! ...Jim'85TE
lotusguy said:
Remember, the proper procedure has you running the belt for at least two minutes or until warm-up. This allows all the slack to homologate throughout the run of the belt and allows for some stretching. You are to retension as necessary after this initial run-up.
I would caution that you are only supposed to adjust tension of the belt with the engine cold, therefore any retensioning after a warmup would be the next day.
Cheers,
Sanj
Regarding the distributor and teeth allignment...
I eneded up with my distributor 180 degrees out. The quik fix was to simply swap out the spark plugs accordingly.
...As far as you being 1/2 a gear tooth off...
My Esprit appears that way when looking at the gear teeth, but when a close look is taken, there are two very small little points that line up exactly, so I got to where I do not pay a tremendous amount of attention to the teeth, but I use them aas a reference against the two little timing points. As I said, I did get tied up and forgot to check the aux shaft so the plug wires had to be swapped.
Drive topless!!!
Cameron
>> Edited by Autocross7 on Sunday 18th July 23:12
I eneded up with my distributor 180 degrees out. The quik fix was to simply swap out the spark plugs accordingly.
...As far as you being 1/2 a gear tooth off...
My Esprit appears that way when looking at the gear teeth, but when a close look is taken, there are two very small little points that line up exactly, so I got to where I do not pay a tremendous amount of attention to the teeth, but I use them aas a reference against the two little timing points. As I said, I did get tied up and forgot to check the aux shaft so the plug wires had to be swapped.
Drive topless!!!
Cameron
>> Edited by Autocross7 on Sunday 18th July 23:12
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