65 365 HP running issue
10-21-2009, 07:43 AM
#21
Safety Car
Thanks to all those who responded. Here's an update:
Turns out the engine was rebuilt with flat top pistons, and thicker head gaskets (.026), so my compression ratio is no where near stock : (
Compression test and leak down are good. I found a wide open vacuum leak in the A/C line. After isolating, vacuum is 9-10 in Hg. Timing was also set way too far advanced, so I set the timing at 12* btdc. Vacuum advance is correct for the engine (B28), and is working per spec. After isolating the vacuum leak, the engine idled much better; however, I still wanted to check the valve lash.
When through the valve lash tonight (cold procedure). Would have liked to fire it up after the adjustment, but those damn cork gaskets on the valve covers didn't come off in one piece(dammit that brought back memories of high school). This is a nice car, but it's not going to Bloomington Gold, so no cork will be going back on
.
Turns out the engine was rebuilt with flat top pistons, and thicker head gaskets (.026), so my compression ratio is no where near stock : (
Compression test and leak down are good. I found a wide open vacuum leak in the A/C line. After isolating, vacuum is 9-10 in Hg. Timing was also set way too far advanced, so I set the timing at 12* btdc. Vacuum advance is correct for the engine (B28), and is working per spec. After isolating the vacuum leak, the engine idled much better; however, I still wanted to check the valve lash.
When through the valve lash tonight (cold procedure). Would have liked to fire it up after the adjustment, but those damn cork gaskets on the valve covers didn't come off in one piece(dammit that brought back memories of high school). This is a nice car, but it's not going to Bloomington Gold, so no cork will be going back on
.The tighter you set the valves, the sooner you can have your timing "all-in", since tightening the lash effectively increases cam duration, and causes the intake valve to close LATER on the compression stroke (lowers DCR).
An engine produces peak torque when spark advance is set just on the brink of detonation.
If you intend to use premium fuel, then I recommend setting the lash loose. This will effectively make the cam "smaller" and partially compensate for your unduly LOW SCR.
Last edited by 65tripleblack; 10-21-2009 at 10:56 AM.
10-21-2009, 10:15 AM
#22
Racer
Member Since: Apr 2008
Location: PASADENA CALIFORNIA
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Thanks to all those who responded. Here's an update:
Turns out the engine was rebuilt with flat top pistons, and thicker head gaskets (.026), so my compression ratio is no where near stock : (
but those damn cork gaskets on the valve covers didn't come off in one piece(dammit that brought back memories of high school). This is a nice car, but it's not going to Bloomington Gold, so no cork will be going back on.
Turns out the engine was rebuilt with flat top pistons, and thicker head gaskets (.026), so my compression ratio is no where near stock : (
but those damn cork gaskets on the valve covers didn't come off in one piece(dammit that brought back memories of high school). This is a nice car, but it's not going to Bloomington Gold, so no cork will be going back on
.Fel-Pro and others make a good quality cork composition valve cover gaskets. The secret is to use gasket sealer only on the valve covers and not the head. It has been my experience that Cork gaskets seal better especially when you often pull off the valve covers for valve adjustment and reuse the gaskets. (such as with a race car).
Sounds like a nice car, 365 HP with A/C.
Chris, CWPASADENA
10-21-2009, 07:23 PM
#23
Tech Contributor
Thread Starter
Got her fired up this morning, what a difference. Really quieted down a lot. Went on to check the timing. I had trouble adjusting the timing before, so I decided to try constraining the mechanical advance. With the mech adv. constrained, I set the idle to 900 RPM, and set the timing to 12*. Best idle it has had yet. Really stable, solid vacuum. Very happy.
I then removed the constraints from mechanical advance to see if it made a difference. Sure enough, the idle shot up. I checked the timing to see I had an additional 15*(total 27). I constrained the mech advance again, and it went right back to 12*.
My 65 shop manual supplement states the mechanical advance should be 0* at idle, so it appears that the the weights are moving out at idle.
Anyone experience this?
I then removed the constraints from mechanical advance to see if it made a difference. Sure enough, the idle shot up. I checked the timing to see I had an additional 15*(total 27). I constrained the mech advance again, and it went right back to 12*.
My 65 shop manual supplement states the mechanical advance should be 0* at idle, so it appears that the the weights are moving out at idle.
Anyone experience this?
10-21-2009, 09:44 PM
#24
Safety Car
Got her fired up this morning, what a difference. Really quieted down a lot. Went on to check the timing. I had trouble adjusting the timing before, so I decided to try constraining the mechanical advance. With the mech adv. constrained, I set the idle to 900 RPM, and set the timing to 12*. Best idle it has had yet. Really stable, solid vacuum. Very happy.
I then removed the constraints from mechanical advance to see if it made a difference. Sure enough, the idle shot up. I checked the timing to see I had an additional 15*(total 27). I constrained the mech advance again, and it went right back to 12*.
My 65 shop manual supplement states the mechanical advance should be 0* at idle, so it appears that the the weights are moving out at idle.
Anyone experience this?
I then removed the constraints from mechanical advance to see if it made a difference. Sure enough, the idle shot up. I checked the timing to see I had an additional 15*(total 27). I constrained the mech advance again, and it went right back to 12*.
My 65 shop manual supplement states the mechanical advance should be 0* at idle, so it appears that the the weights are moving out at idle.
Anyone experience this?
Last edited by 65tripleblack; 10-21-2009 at 09:47 PM.
11-21-2009, 05:43 PM
#26
Tech Contributor
Thread Starter
As it turns out, I had a bad pick up coil, and the incorrect springs. Now it runs like a top!
Thanks to all who replied..
On to my oil pressure problem.......
Thanks to all who replied..
On to my oil pressure problem.......
11-21-2009, 06:07 PM
#27
Melting Slicks
Got her fired up this morning, what a difference. Really quieted down a lot. Went on to check the timing. I had trouble adjusting the timing before, so I decided to try constraining the mechanical advance. With the mech adv. constrained, I set the idle to 900 RPM, and set the timing to 12*. Best idle it has had yet. Really stable, solid vacuum. Very happy.
I then removed the constraints from mechanical advance to see if it made a difference. Sure enough, the idle shot up. I checked the timing to see I had an additional 15*(total 27). I constrained the mech advance again, and it went right back to 12*.
My 65 shop manual supplement states the mechanical advance should be 0* at idle, so it appears that the the weights are moving out at idle.
Anyone experience this?
I then removed the constraints from mechanical advance to see if it made a difference. Sure enough, the idle shot up. I checked the timing to see I had an additional 15*(total 27). I constrained the mech advance again, and it went right back to 12*.
My 65 shop manual supplement states the mechanical advance should be 0* at idle, so it appears that the the weights are moving out at idle.
Anyone experience this?
'65 L76
