1800 engine compression

Keep it on topic, it will make it easier to find what you need.
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jlw35
Posts: 130
Joined: Mon May 20, 2013 7:18 am
Your car is a: 1975 spider

1800 engine compression

Post by jlw35 »

Just did a compression test after noticing excessive bluish smoke from exhaust.

#1 129
#2 80
#3 125
#4 120

So I get that #2 is a problem, do the other numbers seem reasonable?
Just finished with a new head gasket, no leaks during warm-up. I had a post under "crankshaft help" in this forum which related to a nut that was swallowed through the carb and ended up lodged by the #2 exhaust valve (valve did not look damaged, but...).

Suggested next step?
My hope is that someone will say to adjust the valves, doubt I will hear that so I'm open.

Thanks
Jeff
djape1977
Posts: 985
Joined: Sat Apr 21, 2012 6:08 pm
Your car is a: 1970 fiat 124bc
Location: Belgrade, Serbia, eastern Europe

Re: 1800 engine compression

Post by djape1977 »

well, for starters, check valve clearances
So Cal Mark

Re: 1800 engine compression

Post by So Cal Mark »

did you check to see if that valve was sealing? You really need to do a leakdown test to determine if the rings are the problem
jlw35
Posts: 130
Joined: Mon May 20, 2013 7:18 am
Your car is a: 1975 spider

Re: 1800 engine compression

Post by jlw35 »

Mark,

When I had the head off a week ago, I poured some fuel on top of each cylinder. That test (if you can call it accurate) was good I thought. The fuel sat on top of the cylinder for at least :10 minutes.

My attempt at a test on the valves while the head was off was done awkwardly at best, so I can't say if it was successful or not.

Is it possible to do a leakdown test of the valves with the head on the engine by removing the cam cover gaskets? If so, would I use fuel for the test and what sort of parameters would you expect.

Thanks to all
Jeff
So Cal Mark

Re: 1800 engine compression

Post by So Cal Mark »

turn the head upside down, turn the cams so the valves are closed and fill the combustion chamber with solvent
fiatfactory
Posts: 506
Joined: Sun Jun 13, 2010 11:22 pm
Your car is a: 1970 128

Re: 1800 engine compression

Post by fiatfactory »

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Last edited by fiatfactory on Tue Jul 02, 2019 7:01 am, edited 1 time in total.
nothing to see here... move along.
jlw35
Posts: 130
Joined: Mon May 20, 2013 7:18 am
Your car is a: 1975 spider

Re: 1800 engine compression

Post by jlw35 »

Ok, appreciate all the advice.

Work to do this week I suppose.

Anyone know of a good machine shop in the St. Louis, MO area?

Jeff
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