Marbles in my engine - '78 Spider

The forum for all of your technical questions on your classic FIAT autos
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Re: Marbles in my engine - '78 Spider

Post by MrBlimp » Wed Apr 17, 2019 8:20 pm

davedecker4 wrote:
Mon Apr 15, 2019 1:13 pm
So is the replaced gear also plastic or just the one removed to replace?
YES it is.
davedecker4 wrote:
Mon Apr 15, 2019 1:13 pm
If you have the type of stethoscope with the metal rod at the end, you can put it on or around the tensioner bearing and listen for difference, or louder noise. Then compare to cam gear.
YES I do - I'll se if I can do as you suggest.
davedecker4 wrote:
Mon Apr 15, 2019 1:13 pm
If you don't know when tensioner bearing was done, it may be a good idea. Its best to change with timing belt,
I plan on changing the tensioner bearing.
bartigue wrote:
Mon Apr 15, 2019 2:42 pm
A normal timing belt procedure is to change the belt, water pump, and tensioner bearing. In your case, change the timing gear as well.
I wasn't planning on changing the water pump but will consider it based on your advice.
bartigue wrote:
Mon Apr 15, 2019 2:42 pm
Personally I'd set that motor at an intermediate position (all pistons 1/2 way up) and put a socket and drill on that intake cam and spin it, listening for noises. If none then reassemble (use the new gear anyway).
I will definitely give this a try and see how the camshaft sounds.

I'm going to order the parts and schedule a weekend to work on it.

In the meantime I won't be driving it anymore unless it is just to move it in the driveway (our driveway is long and right now it is the first car in - I had to empty the driveway last weekend for a delivery of wood chips, so I had to park the cars out in the street and then move them back again afterwards).
1969 Triumph Spitfire
1970 MGB
1978 FIAT 124 Spider
1992 Mustang LX
2000 Jeep Wrangler Sport
2000 Ford Rangler XLT
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Re: Marbles in my engine - '78 Spider

Post by miker » Thu Apr 18, 2019 9:25 am

In the while you are in there department, check for oil leaks from the seals at the front of the camshaft, aux shaft and front crank.
MikeR ( since 1995)

1977 Fiat 124 Spider
Previously owned:
2012 Fiat 500 Prima Edizione #236 (now owned by my son David)
'86 Bertone X1/9
'81 Fiat Spider 2000 #236
'78 Fiat 131 four door
'76 Fiat 128 4 door
'74 Fiat 128 4 door
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Re: Marbles in my engine - '78 Spider

Post by kmead » Thu Apr 18, 2019 5:19 pm

On Xweb there have been a few of the phenolic cam pulleys that the center section fails and the cam can move relative to the pulley. It makes exactly the sound you are complaining of as it gets loaded by pulling the cam over the lifter and then having it snap back and then pulling the cam over the next lifter.

I would definitely do a timing belt, timing belt bearing and be prepared to replace the cam pulley.
1969 850 Sport Coupe
1970 124 Sport Coupe
1985 X1/9, ugly but fun to drive. Olive trees are hell on paint and interiors apparently. Who knew?
1987 X1/9 slowly coming back
And a few appliances for day to day
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Re: Marbles in my engine - '78 Spider

Post by bartigue » Thu Apr 18, 2019 8:08 pm

Let's call them what they are - 40 year old pieces of plastic. No one should be running one in any part of the belt drive.
Brad Artigue
1969, 1969, 1970, 1979, 1980, 1981, 1982, and 1982 124 Spiders
1969, 1970 850 Spiders
77 X1/9
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