Timing belt replacement question

Maintenance advice to keep your Spider in shape.
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124Germ

Timing belt replacement question

Post by 124Germ »

I know there are a lot of threads about the replacement of the timing belt and I think I understand that whole process, but I have one other concern.

Right now I have the front of the car on jack stands to replace the exhaust hanger...while I have it up I thought I would get the timing belt changed out too.

So to my question finally....Once I have the timing marks lined up, loosen the tensioner, and remove the old belt...are there any chances of the cams or aux cam shifting prior to putting on the new belt? I have read that once I have the marks all lined up, put the transmission in gear to hold it all together, but once the belt is removed everything is free to move .

I am hoping to get this all done in the next couple of weeks while the weather is still a bit crappy outside.

Thanks for all your help over the past months.
Jeremy
SoFlaFiat

Re: Timing belt replacement question

Post by SoFlaFiat »

The auxiliary shaft pulley is the only one which might move freely. When simply changing the belt, I have not worried about lining everything up. Loosen the tensioner, remove the old, install the new without moving anything and it will line up no matter where in the cycle it stopped. Maybe it is better practice to find TDC etc....
124Germ

Re: Timing belt replacement question

Post by 124Germ »

I thought about doing to the same thing, but when the tensioner is applied, the slack could rotate either the cams or the Aux shaft and knowing how everything lines up would help recognize an out of sync situation.
dmwhiteoak
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Your car is a: 1972 Fiat 124 spider
Location: White Oak Tx

Re: Timing belt replacement question

Post by dmwhiteoak »

Yes. It's almost certain they will move a little while installing the belt. Putting trans in gear will help keep the crank from moving. Use the marks on the cam towers to keep the cam pulleys lined up. Maybe Alan just has more luck than I do.
Dennis Modisette

1972 124 Spider
2003 Chevrolet Z71
2007 GMC Yucon
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azruss
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Your car is a: 80 Fiat 2000 FI

Re: Timing belt replacement question

Post by azruss »

if the back is on jack stand, then putting it is gear wont help unless the e-brake is set. You will find each wheel needs to be adjusted to get the cog in place. The biggest issue is the aux pulley as the belt makes contact on both sides and all the slack must be removed between the crank and the aux pulley. I have the best luck getting the belt tight to the aux pulley then stringing CCW to the cams rotating each slightly to pull the tension tight before the next one. The cam pulleys seem to always be off about a 1/2 cog from the pointer and hole.
124Germ

Re: Timing belt replacement question

Post by 124Germ »

Will that half a cog off mess up the timing and rotating assembly?

It sounds like a lot of patience will be required to get it right and don't rush it.

Thanks
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RRoller123
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Your car is a: 1980 FI SPIDER 2000
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Re: Timing belt replacement question

Post by RRoller123 »

As I remember replacing mine, azruss is right, the cam pulleys were off by about a 1/2 cog and it drove me nuts, but you can't do anything about it without adjustable cam gears. As I remember doing it, I think it works best if you start working the belt on going up the right side of the loop (as looking at the front of the engine), Crank to Aux to Intake cam to Exhaust cam, then down the left side. The teeth hold everything in position as you then let the tensioner take up the slack.
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124Germ

Re: Timing belt replacement question

Post by 124Germ »

Sounds like a good idea. First will be tackling the replacement water pump, then to try and get the old belt off and new one on.

Any idea how to prevent antifreeze running down all over everything when removing the water pump? I have drained and removed the radiator and the T section coming off the water pump.

Thanks everyone.
Jeremy
wizard124
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Joined: Mon Oct 29, 2012 9:27 pm
Your car is a: 1980 124 spider FI
Location: Sheridan, WY exSan Rafael, CA

Re: Timing belt replacement question

Post by wizard124 »

I found i needed to have the crank pulley 10-15 degrees BTDC, install the belt around crank and aux shaft. Then rotate the crank pulley to TDC. This action ensures a tight belt to the intake pulley. Next, work the belt over the exhaust wheel. It is a trial and error process.

Once you have it done, rotate the engine through a complete cycle or 2. This ensures the aux cam lobe is correctly positioned and doesnt interfere. Also recheck your timing marks. If your happy, tighten down the tensioner.
SoFlaFiat

Re: Timing belt replacement question

Post by SoFlaFiat »

I will + 3 working counter clockwise from the crank taking up slack as you go!
Dennis, I sure hope my luck holds out!! ;)
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bradartigue
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Joined: Thu Sep 20, 2007 2:35 pm
Your car is a: 1970 Sport Spider
Location: Atlanta, GA

Re: Timing belt replacement question

Post by bradartigue »

124Germ wrote:I know there are a lot of threads about the replacement of the timing belt and I think I understand that whole process, but I have one other concern.

Right now I have the front of the car on jack stands to replace the exhaust hanger...while I have it up I thought I would get the timing belt changed out too.

So to my question finally....Once I have the timing marks lined up, loosen the tensioner, and remove the old belt...are there any chances of the cams or aux cam shifting prior to putting on the new belt? I have read that once I have the marks all lined up, put the transmission in gear to hold it all together, but once the belt is removed everything is free to move .

I am hoping to get this all done in the next couple of weeks while the weather is still a bit crappy outside.

Thanks for all your help over the past months.
Jeremy
Leave it in gear with the brake on; even a minor movement by the car can move the crank. Otherwise this isn't a very hard job to tackle, things can move a little when installing but it is manageable.
124Germ

Re: Timing belt replacement question

Post by 124Germ »

I have the front on jack stands already and the E-Brake set, Once I get the timing set manually, I will put it in gear to hold it.

Thanks everyone for your tips. Now to pick up the 1 1/2" socket and the RTV for the waterpump.
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bradartigue
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Joined: Thu Sep 20, 2007 2:35 pm
Your car is a: 1970 Sport Spider
Location: Atlanta, GA

Re: Timing belt replacement question

Post by bradartigue »

124Germ wrote:I have the front on jack stands already and the E-Brake set, Once I get the timing set manually, I will put it in gear to hold it.

Thanks everyone for your tips. Now to pick up the 1 1/2" socket and the RTV for the waterpump.
RTV for what? Why? If you feel compelled to use RTV (silicone) on anything then use a tiny amount. As in about 1mm, the tiniest amount you can get out of the tube. That stuff will stretch under pressure and get all in your motor if you aren't careful.

My .02 - if you need RTV on a TC motor then something has warped.
124Germ

Re: Timing belt replacement question

Post by 124Germ »

everything i had read states that red rtv should be used along with the gasket for the water pump. today i actually picked up a few different types of gasket sealant
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bradartigue
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Your car is a: 1970 Sport Spider
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Re: Timing belt replacement question

Post by bradartigue »

124Germ wrote:everything i had read states that red rtv should be used along with the gasket for the water pump. today i actually picked up a few different types of gasket sealant
I've never used sealant on anything on a FIAT coolant system. I soak my gaskets in engine oil (clean oil) and install them to the proper torque. Easy and done. If you clean your surfaces and use the correct torques then you won't have a problem. If you insist on using it, use a tiny bead and keep it to the exterior half of the gasket.

Understand that a 1mm bead of RTV, when put under a gasket that is torqued, is going to spread out to about 4mm wide. Your gasket is maybe 6mm wide. I've seen guys use RTV like they're sealing a bathtub, and they pat themselves on the back because they wipe it clean...but inside that crap is all in your cooling system, your radiator, etc.
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