zero compression
Thread Starter
Pro
Joined: Jul 2020
Posts: 642
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From: Miami florida
can you turn the engine with a wrench? turn the engine until #1 exhaust is just closing. at the point that the exhaust is just finishing closing and #1 intake is just opening, number 6 should be right at TDC. then you can verify with the timing mark. if you didn't put a new plastic tooth chain in, it did NOT jump any teeth.
Last edited by michael lamoglia; Apr 9, 2021 at 07:22 PM.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
Don't point fingers at a beautiful Edelbrock Intake. It had and has nothing to do with your issues. LOL
When the carb back fired, that is a common action because your IGN timing was close but slightly advanced. After all, you just stabbed the dizzy in.
And yes, it could have been 180* out. That's an easy check if the left valve cover is off anyway.
Something tells me your "valve-lash" procedure is not up to snuff. Look at it this way. If you removed all the pushrods so the valves could not open you would still have compression right? Then you set the valve lash and the compression goes kaput. H-m-m-m-m-m-m-.
And refresh my memory instead of having to backtrack 80 some post. You just installed a new timing chain set?
When the carb back fired, that is a common action because your IGN timing was close but slightly advanced. After all, you just stabbed the dizzy in.
And yes, it could have been 180* out. That's an easy check if the left valve cover is off anyway.
Something tells me your "valve-lash" procedure is not up to snuff. Look at it this way. If you removed all the pushrods so the valves could not open you would still have compression right? Then you set the valve lash and the compression goes kaput. H-m-m-m-m-m-m-.
And refresh my memory instead of having to backtrack 80 some post. You just installed a new timing chain set?
Last edited by HeadsU.P.; Apr 9, 2021 at 07:49 PM.
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,398
From: SW Florida.
wait wait, number 6!?? Shouldnt it be at 1 since I just got it to close? New chain is metal. And even if I got it at 6 instead of 1, I should still have compression at 1 when turning 360 degrees no? Thanks man and yes I turn it with my socket never by cranking engine
1 and 6 8 and 5 4 and 7 3 and 2. 6 is firing as 1's valves are at their overlap point. and timing pointer sez TDC. crank doesn't care 1 or 6. that is the camshaft's problem.
Last edited by derekderek; Apr 9, 2021 at 08:25 PM.
Old Pro Solo Guy
Joined: Dec 2017
Posts: 7,941
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From: Marlton NJ
I agree with headsup. It has to be your valve lash procedure. Valves hold oil, pistons look good, cam looks good. etc. Only thing left to give zero compression is the valves are hanging open.
I watched your video and saw how you did the valve lash, by turning the pushrod. It is actually very easy this way to get the valves too tight, if you have a strong grip. I suggest a different procedure to lash the valves. Wiggle the pushrod up and down, or the tip of the rocker. Listen for the click because it's loose. Tighten slowly. The click will change as the clearance gets smaller. Right when the click goes away stop, NOW you are at zero lash. Now for this test do not even turn it another "1/2 turn". Just for fun check it with your fingers and I'll bet you can still turn the pushrod,. The spring in the hydraulic lifters is very light.
Go ahead and try it now while only one head is on. Maybe just do one cylinder. Test the compression on that cylinder. Bet it's back!
I watched your video and saw how you did the valve lash, by turning the pushrod. It is actually very easy this way to get the valves too tight, if you have a strong grip. I suggest a different procedure to lash the valves. Wiggle the pushrod up and down, or the tip of the rocker. Listen for the click because it's loose. Tighten slowly. The click will change as the clearance gets smaller. Right when the click goes away stop, NOW you are at zero lash. Now for this test do not even turn it another "1/2 turn". Just for fun check it with your fingers and I'll bet you can still turn the pushrod,. The spring in the hydraulic lifters is very light.
Go ahead and try it now while only one head is on. Maybe just do one cylinder. Test the compression on that cylinder. Bet it's back!
Thread Starter
Pro
Joined: Jul 2020
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From: Miami florida
I hope so man. Now the question becomes: you want me to stop at ZERO lash and not give it 1/2" turn afterwards? and I'm assuming you want me to try when both exhaust/intake rockers are up and lifters are flat at the bottom of the push rods?
Thread Starter
Pro
Joined: Jul 2020
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From: Miami florida
This seems like a good deal for my budget:
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https://www.speedwaymotors.com/Small...Stud,6562.html
https://www.speedwaymotors.com/Flo-T...it,423772.html
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1967 Pedal Car Champion
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From: US-PNW
Something that caught my ears and eyes in your video is that you keep saying the rotor is pointing to #1 but thatonly applies if the #1 spark plug wire is going into that corresponding distributor cap tower. On many C3 engines the #1 tower is closer to pointing at #2 or #4 cylinder. What tower the spark plug wire goes into is not important; what is important is maintaining the firing order. Check to see which tower your #1 plug wire is attached to and when you set the distributor back in the block make sure the rotor is relatively aligned with that tower.
You also said that the rockers were coming up (1:10 min mark) when you hand-cranked it to the TDC mark. This may be just a misinterpretation of what you are referring to so maybe I'm off base: They should not be coming up at all – both valve pushrods should be down and not moving with the valve end of the rocker up and the springs in as uncompressed as they can get. If either rocker is moving or the springs are compressed you are not on #1 TDC.
If'n it were my engine, I would install the heads, torqued correctly, and back off all the rocker nuts so the rockers were flopping around and then do a compression check. This will eliminate all valve lash settings and indicate the sealing capabilities of the rings, head gasket and valve seats. If compression is low, squirt oil into each cylinder to seal the rings and retest. If this raises compression your rings are bad; if no change, then test the sealing of the valves to valve seats.
I think if you go with a composite head gasket you've just negated much of the increased compression by going with the slightly smaller chamber volume of the new heads.
You also said that the rockers were coming up (1:10 min mark) when you hand-cranked it to the TDC mark. This may be just a misinterpretation of what you are referring to so maybe I'm off base: They should not be coming up at all – both valve pushrods should be down and not moving with the valve end of the rocker up and the springs in as uncompressed as they can get. If either rocker is moving or the springs are compressed you are not on #1 TDC.
If'n it were my engine, I would install the heads, torqued correctly, and back off all the rocker nuts so the rockers were flopping around and then do a compression check. This will eliminate all valve lash settings and indicate the sealing capabilities of the rings, head gasket and valve seats. If compression is low, squirt oil into each cylinder to seal the rings and retest. If this raises compression your rings are bad; if no change, then test the sealing of the valves to valve seats.
I think if you go with a composite head gasket you've just negated much of the increased compression by going with the slightly smaller chamber volume of the new heads.
Thread Starter
Pro
Joined: Jul 2020
Posts: 642
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From: Miami florida
Something that caught my ears and eyes in your video is that you keep saying the rotor is pointing to #1 but thatonly applies if the #1 spark plug wire is going into that corresponding distributor cap tower. On many C3 engines the #1 tower is closer to pointing at #2 or #4 cylinder. What tower the spark plug wire goes into is not important; what is important is maintaining the firing order. Check to see which tower your #1 plug wire is attached to and when you set the distributor back in the block make sure the rotor is relatively aligned with that tower.
Definitely tower to 1. I followed this video:
https://www.youtube.com/watch?v=O4WR...&index=28&t=7s
You also said that the rockers were coming up (1:10 min mark) when you hand-cranked it to the TDC mark. This may be just a misinterpretation of what you are referring to so maybe I'm off base: They should not be coming up at all – both valve pushrods should be down and not moving with the valve end of the rocker up and the springs in as uncompressed as they can get. If either rocker is moving or the springs are compressed you are not on #1 TDC.
Basically this is what I did on this video:
If'n it were my engine, I would install the heads, torqued correctly, and back off all the rocker nuts so the rockers were flopping around and then do a compression check. This will eliminate all valve lash settings and indicate the sealing capabilities of the rings, head gasket and valve seats. If compression is low, squirt oil into each cylinder to seal the rings and retest. If this raises compression your rings are bad; if no change, then test the sealing of the valves to valve seats.
Good idea will try
I think if you go with a composite head gasket you've just negated much of the increased compression by going with the slightly smaller chamber volume of the new heads.
Definitely tower to 1. I followed this video:
https://www.youtube.com/watch?v=O4WR...&index=28&t=7s
You also said that the rockers were coming up (1:10 min mark) when you hand-cranked it to the TDC mark. This may be just a misinterpretation of what you are referring to so maybe I'm off base: They should not be coming up at all – both valve pushrods should be down and not moving with the valve end of the rocker up and the springs in as uncompressed as they can get. If either rocker is moving or the springs are compressed you are not on #1 TDC.
Basically this is what I did on this video:
If'n it were my engine, I would install the heads, torqued correctly, and back off all the rocker nuts so the rockers were flopping around and then do a compression check. This will eliminate all valve lash settings and indicate the sealing capabilities of the rings, head gasket and valve seats. If compression is low, squirt oil into each cylinder to seal the rings and retest. If this raises compression your rings are bad; if no change, then test the sealing of the valves to valve seats.
Good idea will try
I think if you go with a composite head gasket you've just negated much of the increased compression by going with the slightly smaller chamber volume of the new heads.
Safety Car
Joined: Nov 2008
Posts: 3,707
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From: Seattle Washington
If the Intake Valves are not opening then it can't make compression. The Valve Train has to be in adjustment to get a true reading of compression that pertains to whats right and whats wrong.
Safety Car
Joined: Nov 2008
Posts: 3,707
Likes: 550
From: Seattle Washington
If the engine still looks like it did in the last picture with one head still on and the Valve Train still intact You could have somebody roll the engine over with the starter and put your thumb over the Spark Plug holes. I'd be willing to bet it blows your thumb off the plug hole. You won't want to do this for long and keep an eye on the loose Lifters on the other side. The Engine won't Oil correctly but it will only take a revolution or two to find out. If You can't hold back the Air in the Cylinder then You have Compression.
Le Mans Master
Joined: May 2007
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From: North tonawanda NY
wait wait, number 6!?? Shouldnt it be at 1 since I just got it to close? New chain is metal. And even if I got it at 6 instead of 1, I should still have compression at 1 when turning 360 degrees no? Thanks man and yes I turn it with my socket never by cranking engine
Le Mans Master
Joined: May 2007
Posts: 5,007
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From: North tonawanda NY
Mike , when you adjusted your lash, you only tightened the ones that were connected to the lifters that were at at the bottom of their stroke right? (when they are not pushing a rocker up and valve open) Thats how I normally do it anyway, then I advance the engine rotation and adjust the rest when they move into that position otherwise there would already be tension on those rods whether they were adjusted properly or not. Sorry not sure it this makes sense the way im explaining it.
also this is a stupid question but you didnt possibly leave a spark plug installed did you? because this would give you that resistance you spoke of when you turned it over by hand when that cylinder got to its compression stroke.
Last edited by augiedoggy; Apr 10, 2021 at 08:55 AM.
Thread Starter
Pro
Joined: Jul 2020
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From: Miami florida
That more or less what ive been thinking and saying all along... Its the only change he has made other than removing and reinstalling the intake and that would not cause this.
Mike , when you adjusted your lash, you only tightened the ones that were connected to the lifters that were at at the bottom of their stroke right? (when they are not pushing a rocker up and valve open) Thats how I normally do it anyway, then I advance the engine rotation and adjust the rest when they move into that position otherwise there would already be tension on those rods whether they were adjusted properly or not. Sorry not sure it this makes sense the way im explaining it.
also this is a stupid question but you didnt possibly leave a spark plug installed did you? because this would give you that resistance you spoke of when you turned it over by hand when that cylinder got to its compression stroke.
Mike , when you adjusted your lash, you only tightened the ones that were connected to the lifters that were at at the bottom of their stroke right? (when they are not pushing a rocker up and valve open) Thats how I normally do it anyway, then I advance the engine rotation and adjust the rest when they move into that position otherwise there would already be tension on those rods whether they were adjusted properly or not. Sorry not sure it this makes sense the way im explaining it.
also this is a stupid question but you didnt possibly leave a spark plug installed did you? because this would give you that resistance you spoke of when you turned it over by hand when that cylinder got to its compression stroke.
good morning. I did the rotation in the lash according to the video. Most videos I see show people just going round robin which is crazy. No spark plug in when turning. When I get home from baseball game will try all steps can’t wait for posting it hopefully we will be good
Thread Starter
Pro
Joined: Jul 2020
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From: Miami florida
yes that chain was changed a long while ago. Remember I’m the nice that had to change the damper and I then replaced the original nylon. You were one of those that helped me make it great till I broke it just now lol
Thread Starter
Pro
Joined: Jul 2020
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From: Miami florida
If the engine still looks like it did in the last picture with one head still on and the Valve Train still intact You could have somebody roll the engine over with the starter and put your thumb over the Spark Plug holes. I'd be willing to bet it blows your thumb off the plug hole. You won't want to do this for long and keep an eye on the loose Lifters on the other side. The Engine won't Oil correctly but it will only take a revolution or two to find out. If You can't hold back the Air in the Cylinder then You have Compression.