How do i check block and rings

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fiatfactory
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Joined: Sun Jun 13, 2010 11:22 pm
Your car is a: 1970 128

Re: How do i check block and rings

Post by fiatfactory »

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Last edited by fiatfactory on Tue Jul 02, 2019 5:59 am, edited 1 time in total.
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vandor
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Joined: Sat May 23, 2009 1:23 pm
Your car is a: 1971 124 Spider
Location: Texas, USA

Re: How do i check block and rings

Post by vandor »

If you ar getting those compression number then I do not think the cams are 180 out. Checking the timing marks would tell you if they are correct or not, or how far off they are.
BTW, there is no such things are 180 degrees out: since the cams rotate at half the engine speed, the crankshaft rotates twice for every one revolution of the cams. So the number one piston is at Top Dead Center TWICE during one revolution of the cams. Thus the #1 (and #4) pistons will be at TDC when the cam timing marks are aligned and also when they are 180 degrees (half a revolution) out.
If they are 180 degrees out simply rotate the crankshaft one revolution and they should now be aligned with the marks.
Csaba
'71 124 Spider, much modified
'17 124 Abarth, silver
http://italiancarclub.com/csaba/
Co-owner of the best dang Fiat parts place in town
fiatfactory
Posts: 506
Joined: Sun Jun 13, 2010 11:22 pm
Your car is a: 1970 128

Re: How do i check block and rings

Post by fiatfactory »

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Last edited by fiatfactory on Tue Jul 02, 2019 5:59 am, edited 1 time in total.
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bradartigue
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Re: How do i check block and rings

Post by bradartigue »

fiatfactory wrote:Of course Csaba's correct.

But when someone says to me "180 out", I guess I assumed (that word again) with no pictures involved of the timing marks to show otherwise, that the guy was talking about the cam marks lining up as they should, and the crank mark was entirely 180 degrees off...so 2/3 pistons were at TDC when the cam gear holes lined up with their markers... that's 180 out to me... the other scenario is someone not understanding the four stroke cycle and simply not rotating the crank another full revolution...

Bammbamm, please tell us that's not the case and you understand the four stroke cycle...

SteveC
Yes "assumed" is a bad one, I assumed it to mean the cams were 180 off their marks - which means they would collide.
BammBamm
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Your car is a: 1982 Pininfarina Spider
Location: az

Re: How do i check block and rings

Post by BammBamm »

Ok.. I have a new puzzle. I set the cams to the correct timing. When i hand crank the engine around the #2 cylinder hit the exhaust valve. A definate mechanical stop from it. I cant figure out what the PO did to this engine. I can assume the crankcase pulley has a key way. Is it possible to put the cam pulleys on incorrectly? Could he have installed the cams on the wrong side? I don't get it

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Bill Woodbury
Design Engineer
Zero Shock Seating
1982 Spider 2000
lanciahf

Re: How do i check block and rings

Post by lanciahf »

Did you time the Aux pulley? The fuel pump lobe on the aux shaft will hit #2 if mis-timed.
fiatfactory
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Re: How do i check block and rings

Post by fiatfactory »

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Last edited by fiatfactory on Tue Jul 02, 2019 6:00 am, edited 1 time in total.
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BammBamm
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Re: How do i check block and rings

Post by BammBamm »

To answer more questions. When I said the cams were 180 out of time. That meant, from the correct location, the allignment holes were 180 degrees off when the crankshaft pulley tdc marks alligned. So since, the cams rotate at half the rate they would have technically been 90 degrees out. I have not done anything with the aux pulley. I will research what to do with that tonight, unless you could specify a procedure. It sounds like a likely culprit for my symptoms. Thanks for all your help
Last edited by BammBamm on Sun Aug 23, 2015 12:23 am, edited 1 time in total.
Bill Woodbury
Design Engineer
Zero Shock Seating
1982 Spider 2000
vandor
Posts: 3996
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Your car is a: 1971 124 Spider
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Re: How do i check block and rings

Post by vandor »

The timing mark on the auxiliary pulley should point in the 1 o'clock direction. It does not have to be super precise.
I usually point toward the tensioner's pivot bolt.
Csaba
'71 124 Spider, much modified
'17 124 Abarth, silver
http://italiancarclub.com/csaba/
Co-owner of the best dang Fiat parts place in town
BammBamm
Posts: 240
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Your car is a: 1982 Pininfarina Spider
Location: az

Re: How do i check block and rings

Post by BammBamm »

I appreciate everyones help. I lined all the timing up and it still has no compression on cylinder 1. So im back to my plan of recieve the new used FI head. Have a machine shop check it out. I will pull the head from the 82 engine. If i find a physical problem with the gasket or valve on the 82 then i will mount the new FI head. If i dont find anything obvious then I have to assume it the rings. I will then tear down the 79 engine and install the fi head. One way or another I will have a running car soon.
Bill Woodbury
Design Engineer
Zero Shock Seating
1982 Spider 2000
fiatfactory
Posts: 506
Joined: Sun Jun 13, 2010 11:22 pm
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Re: How do i check block and rings

Post by fiatfactory »

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Last edited by fiatfactory on Tue Jul 02, 2019 5:58 am, edited 1 time in total.
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BammBamm
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Your car is a: 1982 Pininfarina Spider
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Re: How do i check block and rings

Post by BammBamm »

So as a last thing before pulling the head, I decided to check the gap on the cams.. The #1 exhaust valve never reaches any clearance from the cam lobe. i used a .0015 feeler gauge and it wouldnt fit at any part of the rotation.what is the procedure to change the clearance and what should the clearance be?
Bill Woodbury
Design Engineer
Zero Shock Seating
1982 Spider 2000
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bradartigue
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Re: How do i check block and rings

Post by bradartigue »

BammBamm wrote:So as a last thing before pulling the head, I decided to check the gap on the cams.. The #1 exhaust valve never reaches any clearance from the cam lobe. i used a .0015 feeler gauge and it wouldnt fit at any part of the rotation.what is the procedure to change the clearance and what should the clearance be?
You need to get a service manual. Search the forum, plenty are available online.
fiatfactory
Posts: 506
Joined: Sun Jun 13, 2010 11:22 pm
Your car is a: 1970 128

Re: How do i check block and rings

Post by fiatfactory »

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Last edited by fiatfactory on Tue Jul 02, 2019 5:58 am, edited 1 time in total.
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BammBamm
Posts: 240
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Your car is a: 1982 Pininfarina Spider
Location: az

Re: How do i check block and rings

Post by BammBamm »

I saw the previous posts about the cam clearances. Today was the first day i had the right allen to open the covers
Bill Woodbury
Design Engineer
Zero Shock Seating
1982 Spider 2000
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