TDC

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LuisMateoSpider
Posts: 57
Joined: Wed Jul 10, 2013 2:29 am
Your car is a: 124CS1 - Spider 1978

TDC

Postby LuisMateoSpider » Sat May 20, 2017 2:08 am

So I blew my head gasket... :roll: (overheat)
I had milky oil in the dip stick and oil in the coolant inside the radiator, so it was a giveaway that the HG was blown, I replaced the HG and replaced crank front seal gasket as well as the aux shaft gasket that were perish. Putting it all back together I noticed that the intake cam pulley does not "stop" at the TDC marks. Is that normal?
To place the timing belt I had to use a wrench to move the intake pulley to the left a tad so that the belt's teeth would line up with the marks and go in. Having all my marks aligned I cranked the car and started but immediately started to make noises from the inside of the intake cam.

I would like to get some feedback as of where may I have gone wrong. Here is a pic as how my engine marks are lined up.

Image

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hayesbd
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Your car is a: 1973 Spider
Location: Newark, Ohio, USA

Re: TDC

Postby hayesbd » Sat May 20, 2017 7:29 am

This may or may not apply, but on my spider, the clearance in the mounting holes in the plate that forms the two pointers for lining up the cam shaft sprockets allowed the position of the pointers to put the belt one tooth out of position. After realizing that, I set up the cam positions using the raised line on the cam tower castings looking from the back of the sprockets. I also recall having to hold one of the cams in position while putting the belt on. If you have noise, I would suspect bent valves, unfortunately. Next time, rotate the engine by hand without any spark plugs in to make sure it's not hitting anything.

Brian
Current: 1973 124 Spider
Previous: 1961 600D, 1970 850 Racer, 1973 124 Special, 1974 124 Special TC

klweimer
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Joined: Tue Mar 27, 2012 7:45 am
Your car is a: 1982 Spider 2000
Location: Arvada, Colorado

Re: TDC

Postby klweimer » Sat May 20, 2017 7:47 am

As mentioned above, it's entirely possible the cams may not want to "hold" at TDC, because while the valves on cylinder 1 may be closed, valves on other cylinders are at various states of open. I don't believe you will bend any valves if you're close to the correct position on the cams.

I would be much more suspicious of the aux shaft timing being off and being hit by the crank. I can't tell from the picture how it is lined up.

Kirk

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So Cal Mark
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Re: TDC

Postby So Cal Mark » Sat May 20, 2017 9:19 am

it's hard to tell from your pic but it looks like the aux shaft is not timed correctly. With the engine on tdc the aux shaft timing marks should line up with the tensioner pivot bolt.
Cam timing off by one tooth won't cause valve/piston contact. If the noise was from bent valves the engine would run very rough.
Mark Allison
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LuisMateoSpider
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Your car is a: 124CS1 - Spider 1978

Re: TDC

Postby LuisMateoSpider » Sat May 20, 2017 11:08 pm

hayesbd wrote:This may or may not apply, but on my spider, the clearance in the mounting holes in the plate that forms the two pointers for lining up the cam shaft sprockets allowed the position of the pointers to put the belt one tooth out of position. After realizing that, I set up the cam positions using the raised line on the cam tower castings looking from the back of the sprockets. I also recall having to hold one of the cams in position while putting the belt on. If you have noise, I would suspect bent valves, unfortunately. Next time, rotate the engine by hand without any spark plugs in to make sure it's not hitting anything.

Brian


Brian,
I found in a thread that the cams have the raised line and I made sure they are also aligned, both intake and exhaust are in line. during dismantling I rotated the engine and it did not make a full cycle, initially I thought it was the pressure from the spark plugs being on but I took them out and it was still not going all the way.
To me it did not make sense since I drove the car in to the garage the day before starting all the work, may be the belt skipped as I was turning it, eventually it did a hole cycle and continued with the dismantling.
Could it be that it was not initially timed correctly? or that it skipped a tooth?
Here is a pic of the cams from the back of the sprockets.

Intake
Image

Exaust
Image

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LuisMateoSpider
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Your car is a: 124CS1 - Spider 1978

Re: TDC

Postby LuisMateoSpider » Sat May 20, 2017 11:36 pm

Thank you Kirk and Mark

I'm posting a pic that shows the aux shaft in relation to the tensioner pivot.
I'll put things back together next week and post a video of how is running and the noise that it's making.
Could it be that the aux shaft is off a hole turn?

Image

One thing I saw is that initial timing in this picture shows the crank in line with the aux shaft center and mine is in line with the bottom marker on the cover, should I bring it up?
Image

klweimer
Posts: 550
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Location: Arvada, Colorado

Re: TDC

Postby klweimer » Sun May 21, 2017 8:02 am

Luis,
The aux shaft turns at the same speed at the crankshaft, so you don't have to worry about it being off by a whole turn (like the camshafts), either the holes line up with the pivot bolt or not. What I'n not sure about is the white mark on your crank pulley. Is that your timing mark for ignition timing? I'm pretty sure the crank timing mark should be aligned with the TDC mark on the timing indicator on the passenger side of the engine. I know that's how it is on the 2000, but not sure about the 1800.
Kirk

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RRoller123
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Re: TDC

Postby RRoller123 » Sun May 21, 2017 12:07 pm

Hopefully this will help. That Crankshaft TDC indicator looks off to me, but I am only familiar with the 2L engine.

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LuisMateoSpider
Posts: 57
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Your car is a: 124CS1 - Spider 1978

Re: TDC

Postby LuisMateoSpider » Thu Jun 01, 2017 5:48 pm

Hi,
Today I put it back together a aligned the crank with the Aux shaft bolt and placed the belt back on, it all seems normal.
It fired it up and the noise is still prominent. I took a video so you guys can hear it and hopefully can shed some light in to this.

https://youtu.be/4ywB8HOe0Co

MMRMVA
Posts: 40
Joined: Thu Nov 10, 2022 6:21 pm
Your car is a: 1978 Spider

Re: TDC

Postby MMRMVA » Sun Jan 01, 2023 6:27 pm

Luis, did you ever figure this one out? I have something similar after a new head gasket

https://photos.app.goo.gl/G64tdaaPsDEqhDmg8

18Fiatsandcounting
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Location: San Francisco Bay Area

Re: TDC

Postby 18Fiatsandcounting » Sun Jan 01, 2023 9:09 pm

I'll jump into the discussion in place of Luis. Based on your other thread, it would be a good idea to check the cam timing as this might contribute to the clicking sound.

Remove the #1 spark plug, stick a long screwdriver in the hole, and rotate the crankshaft by hand CLOCKWISE until you "see" that you have reached TDC by the movement of the screwdriver. This is where Yoda steps in and says, "Rotate the crankshaft by hand, you must. Feel The Force flow through you, and there is no try. Do or do not." You can rock the crankshaft back and forth a bit by hand to find the sweet spot of TDC. Use The Force.

Then take a look at the backside of the camshafts. You either will see the holes in both camshaft pulleys lined up with the little nib on the front of the camshaft housings (Hooray!!!) or not. If not, rotate the crankshaft by hand another one revolution and the marks should line up.

If the camshaft pulley holes don't line up with the nibs in the housing, your cams are out of alignment.

-Bryan

Nut124
Posts: 748
Joined: Wed Oct 25, 2017 6:39 pm
Your car is a: 1978 124 Spider 1800

Re: TDC

Postby Nut124 » Sun Jan 01, 2023 10:38 pm

That noise is pretty loud.

I would attempt to investigate whether there is internal interference in the engine. Remove all spark plugs, alternator and water pump belts and turn the engine over by hand with a wrench feeling for any sign of catching or interference. If a valve interferes with a piston, the engine would not want to turn somewhere around 5-10 deg BTDC as either the EX or IN valve is open too far at that point. The other possible source of interference is the aux shaft lobe vs con rod.

To me that noise is too loud to be due to valve clearances. Did you check clearances?

MMRMVA
Posts: 40
Joined: Thu Nov 10, 2022 6:21 pm
Your car is a: 1978 Spider

Re: TDC

Postby MMRMVA » Fri Jan 06, 2023 6:22 pm

Sorry to create multiple threads on this one. But to clear this on up if others find it, our issue was that the timing was way off because we set the distributor too far past the #4 node. Once we corrected that we were on the right track and dialed it in.


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