Hey folks-
Trying to help my father diagnose an issue with our '80 Spider... He is currently completing the restoration and is now working on getting it running well. He started and ran the car for a short time a couple of days ago, but when he went to start it today to tune the carb, the car cranked much faster than normal and would not start. A compression test revealed only 40 on all cylinders... Spark plugs are correct and torqued, and nothing has been changed since the last start a couple days ago. Timing belt is newly-installed as of a few weeks ago, but is it possible it could have broke or slipped off? Any feedback is appreciated, thanks!
Unusually fast cranking
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RenaissanceMan
- Posts: 14
- Joined: Mon Jul 23, 2018 3:27 pm
- Your car is a: 1980 Fiat Spider
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DieselSpider
- Posts: 2130
- Joined: Wed Dec 24, 2014 10:21 pm
- Your car is a: 1978 124 Spider with Isuzu Turbo Diesel
Re: Unusually fast cranking
Slipped timing belt is a distinct possibility and hopefully the valves are not bent. Broken timing belt should give uneven compression. Check the timing marks on the belt, set it right and hope for the best.
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RenaissanceMan
- Posts: 14
- Joined: Mon Jul 23, 2018 3:27 pm
- Your car is a: 1980 Fiat Spider
Re: Unusually fast cranking
Another thought... I have been told that the timing of the oil pump is critical on these cars. If this was out of spec, could it cause a similar issue?
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DieselSpider
- Posts: 2130
- Joined: Wed Dec 24, 2014 10:21 pm
- Your car is a: 1978 124 Spider with Isuzu Turbo Diesel
Re: Unusually fast cranking
That's usually only critical when the distributor is driven by the oil pump as far as I know however that would just cause ignition timing issues and not low compression. Mine has been converted to Diesel power so I am not very familiar with the specifics of the Lamperi engine but mostly Detroit iron.RenaissanceMan wrote:Another thought... I have been told that the timing of the oil pump is critical on these cars. If this was out of spec, could it cause a similar issue?
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blazingspider
- Posts: 173
- Joined: Mon Jan 28, 2013 8:44 am
- Your car is a: 1977 fiat spider
- Location: Nanuet, New York
Re: Unusually fast cranking
Definitely check the timng belt to ensure it has not slipped. Remove the spark plugs and the timing belt cover, if it's still on, and slowly rotate the engine by hand using the crankshaft nut until all the timing marks line up. Before doing so, you may want to check the following:
Was the timing belt tensioned properly and the tensioner bearing locked back down?
Was the crankshaft timing gear replaced? They can get so worn that when you start the engine the gear teeth do not engage with the belt.
On your 1980, the auxillary shaft drives the oil pump but it still has the fuel pump lobe for the old mechanical pumps and if it is not timed correctly the fuel pump lobe can strike the crankshaft. That can result in busting a hole through the block but it would not create the symptoms you are describing.
Last but not least, it's possible that the bendix gear on the starter motor did not enage the teeth on the flywheel but that would not result in a low compression reading either.
Good Luck
Was the timing belt tensioned properly and the tensioner bearing locked back down?
Was the crankshaft timing gear replaced? They can get so worn that when you start the engine the gear teeth do not engage with the belt.
On your 1980, the auxillary shaft drives the oil pump but it still has the fuel pump lobe for the old mechanical pumps and if it is not timed correctly the fuel pump lobe can strike the crankshaft. That can result in busting a hole through the block but it would not create the symptoms you are describing.
Last but not least, it's possible that the bendix gear on the starter motor did not enage the teeth on the flywheel but that would not result in a low compression reading either.
Good Luck