Quote:
Today I ordered a new intake/exhaust manifold gasket from the Rock.
Srsly? You're going to all the work and backache of R&Ring the manifolds and you're not using the good gaskets?Guess you're more of a gambling man than I am.
| Slant Six Forum https://slantsix.org/forum/ |
|
| Got a skip coming from the back three... Conclusion, maybe https://slantsix.org/forum/viewtopic.php?t=48359 |
Page 2 of 3 |
| Author: | Doc [ Tue Apr 10, 2012 3:02 pm ] |
| Post subject: | |
Does the engine run a PCV valve? If so have you tried swapping or "capping-off" the pcv valve as a test? DD |
|
| Author: | wjajr [ Wed Apr 11, 2012 2:06 am ] |
| Post subject: | |
Dan: Quote: Got any vacuum lines tapped in at the #6 intake runner?
Nope, #6 is a bung free zone. |
|
| Author: | wjajr [ Wed Apr 11, 2012 2:40 am ] |
| Post subject: | |
DD: [quote]Does the engine run a PCV valve? If so have you tried swapping or "capping-off" the pcv valve as a test?[/quote] It does have a PCV valve, and I have not tried capping it off. [img]http://i294.photobucket.com/albums/mm87/wjajr/Dart%20Engine/005-1.jpg[/img] [img]http://i294.photobucket.com/albums/mm87/wjajr/Dart%20Engine/100_1460.jpg[/img] Doc, your PCV valve query makes me wonder about recent changes made in carburetor settings this March, and last spring’s manifold and header reinstall. First when reinstalling manifold for some unknown reason I only torqued its bolts to half required specification. After running the car for a short period, I realized my mistake, and re torqued manifold to full rate. Perhaps during this period the Fel-Pro gasket was damaged. Since noticing this skip, I tightened the last three cylinders an additional quarter turn. Secondly when recalibrating Holley 390, I filled the drill holes in throttle plates, and compensated for this loss of air by cracking open secondary throttle plates per Holley tech line so about 0.024†of transition slot is showing. As you can see from top photo, PCV attaches to south end of carburetor. I wonder if there is too much air entering the secondary side of carburetor causing a lean condition to back three cylinders, and number six is taking the biggest hit. Bill |
|
| Author: | wjajr [ Thu Apr 12, 2012 1:22 pm ] |
| Post subject: | |
Today I ordered a new intake/exhaust manifold gasket from the Rock. Hopefully this will knock out the skip. |
|
| Author: | SlantSixDan [ Thu Apr 12, 2012 4:18 pm ] |
| Post subject: | |
Quote: Today I ordered a new intake/exhaust manifold gasket from the Rock.
Srsly? You're going to all the work and backache of R&Ring the manifolds and you're not using the good gaskets?Guess you're more of a gambling man than I am.
|
|
| Author: | Aggressive Ted [ Fri Apr 13, 2012 8:38 pm ] |
| Post subject: | Header Gaskets |
Bill, I am with Dan on this one.......either use the Aussie or the Remflex. At worst a Corteco.......but never a FelPro with headers! |
|
| Author: | wjajr [ Sun Apr 15, 2012 5:00 am ] |
| Post subject: | |
AggTed: Quote: Bill, I am with Dan on this one.......either use the Aussie or the Remflex. At worst a Corteco.......but never a FelPro with headers!
All right already that pile of junk will be sitting until the Good Gasket arrives.Last evening I pulled manifold and headers to inspect gasket for point of vacuum leak, saw none at #6 intake, but I had snugged the manifold bolts up a few days ago. All intake valve stems visible through head ports have quite a black deposit built up. I wouldn’t think this much deposit normal for about 9000 miles of use since head was rebuild a few years ago. All six intake stems look to be close in color and amount of black deposit, and all exhaust stems look to be same color. The intake ports have some black deposit, but also show a golden color where fuel flow must come in contact with its surface. When I get her back together, should I use some decarbonizer or top end cleaner? Also at the first 90 degree bend of header’s #6 runner where it goes around the starter, the paint had degraded and was flaking off. This is the only such spot in all the piping. I’m thinking that indeed #6 was running hot from lean condition. Is this a reasonable assumption? |
|
| Author: | Aggressive Ted [ Sun Apr 15, 2012 9:17 am ] |
| Post subject: | |
Bill, Quote: I’m thinking that indeed #6 was running hot from lean condition. Is this a reasonable assumption?
Yes. Quote: All intake valve stems visible through head ports have quite a black deposit built up. I wouldn’t think this much deposit normal for about 9000 miles of use since head was rebuild a few years ago.
I pulled my head at 48,000 miles since it's last rebuild and found the same condition. I think the large quantities of the CENEX ethanol must be causing the build up since it tends to have a cooling effect and run cooler. I am thinking I may need more intake manifold heat as well as compression. I have never seen this much build up before.....and it's only on intake charge side of the valves. The other half of my valves were clean.The shop that did my head said I should start a regiment of Gumout. All the intake valves cleaned up very easily but the edges were pitted so they were reground. The exhaust valves showed no pitting and were fine. So the intakes were definitely running cool. The guides showed a little slop so we changed all of them. I am not sure what the best thermostat would be after seeing this. I have been running a 195 degree Super Stat. I still have both manifolds bolted together for max heat. |
|
| Author: | wjajr [ Sun Apr 15, 2012 3:18 pm ] |
| Post subject: | |
Ted, I too have a 195 degree thermostat installed, and run 9.5:1 compression. That mess on the intake valves was a surprise, just as bad as the old ones I removed before all the head work. I run a hydronic hot spot feed from heater loop under the manifold which has made a huge difference in drivability in all weather. I’ll look into adding cleaners such as Gumout to the fuel. Based on o2 sensor info I know my mixture is a lot closer to 14.7:1 now than it was for a long time. There are a lot of rich miles on that head. I haven’t probed to see if the deposit is on the up-stream side of air fuel flow. |
|
| Author: | Aggressive Ted [ Sun Apr 15, 2012 8:46 pm ] |
| Post subject: | |
What jets were you running before and what are running now to see 14.7? I would have never dreamed that running a #57 jet in a Holley 1920 would create that much junk on the back side of the intakes. The combustion chambers were nice and clean. Maybe Doc could share a few thoughts....... |
|
| Author: | SlantSixDan [ Sun Apr 15, 2012 9:57 pm ] |
| Post subject: | |
It's not the ethanol, and it's not the thermostat, and it's not the carburetor jet. Might be the fuel -- what brand do you burn, mostly? -- and it might be oil getting past the valve guides. |
|
| Author: | wjajr [ Mon Apr 16, 2012 5:14 am ] |
| Post subject: | |
Dan: Quote: Might be the fuel -- what brand do you burn, mostly? -- and it might be oil getting past the valve guides.
Irving gas fresh from St. John, NB, and Chavez red… rather Chevron. All that nationalism aside; around here it all comes out of the same barge off loaded at the tank farm. Walls of intake runners also have the same dark coating but it is thinner where air fuel stream encounters a bend and is redirected on its way to the valve seat. The engine uses about a quart of oil per 3000 miles some of which ends up on the floor from rear main, and valve lash adjustments. Engine produces no smoke, fresh valve seals were installed and guides are good. Buildup is on intake only, exhaust valve stems have same light dusty blackish soot coating as the ports. I suspect that the cam over-lap, and a lot of driving in the 2000 to 2500 rpm range has caused some of the intake buildup. Once the rpm exceeds 4500 rpm, the engine picks up two more inches of vacuum at steady throttle. Clearly I need a lower rpm range cam in this thing to better match our driving conditions in these parts. |
|
| Author: | wjajr [ Fri Apr 27, 2012 1:05 pm ] |
| Post subject: | |
Update on healing Skippy… or you find the damnedest things if one looks hard enough. We got back from Florida Wednesday; I retrieved the “Good Gasket†from neighbor that was kind enough to collect it up after a Monday delivery. Thursday morning I ordered collector and carburetor gaskets to be delivered tomorrow noon, Saturday. While waiting for gaskets I decided to look into changing the carburetor’s orientation from North-South to East-West. The current ½†spacer-Holley adapter plate won’t allow articulation of throttle due to it bottoming out on manifold. While measuring for thicker spacer needed to remount carburetor lead to the discovery of a possible vacuum leak between manifold and spacer. Half of the gasket was wet with fuel making me think that it was not sealing that portion of contact tightly. The spacer’s bolts were just bottoming out in the Clifford casting just shy of fully compressing gasket. After examining bolts, I discovered someone had ground them shorter to fit, and two were 0.030†longer than the others thus the problem. I fixed that by grinding bolts an additional 0.050†shorter, made a new gasket and installed it. Incidentally the poor seal area was on the secondary side of the carburetor. Some of you may recall a month or two ago I had to bend the secondary throttle plate lock out linkage to keep them from fluttering at idle which caused too much of idle slot to be exposed, and too much idle air introduced. While Carburetor was on the bench, I rechecked the idle circuit slot exposure on the secondary side of carburetor, and readjusted it to Holley’s Tech line instructions to have 0.020†showing when throttle plates are closed. Between new “Good Manifold to Head Gasketâ€, spacer gasket properly torqued, and secondary idle circuit correctly adjusted I’m hoping that the lean condition on the back three and skip will be eliminated. For now I am not going to re-orientate the carburetor. |
|
| Author: | Aggressive Ted [ Fri Apr 27, 2012 3:33 pm ] |
| Post subject: | |
Well????? what is the rest of the story? How does it run???? :shrug: By the way the Remflex collector gaskets are awesome! 
|
|
| Author: | wjajr [ Sat Apr 28, 2012 6:14 am ] |
| Post subject: | |
[quote]Well????? what is the rest of the story? How does it run???? [/quote] Patience there Teddy old bean… I’ll fire it up after installing collector and carburetor base gaskets, which will be about an hour after the mail babe delivers them… Most likely early afternoon EDST. Additional investigation of paint condition on headers during repaint indicated back three were all running lean & hot. I retested valve performance after discovering foot valve in compression test equipment was located in sparkplug end of hose, not gage rendering previous test moot… Dumb, dumb, dumb… I at times wonder how hair is still able to grow in top of my barren scull. I located a cheap air hose that is designed to pressurize a cylinder at the auto parts store, and repeated the valve leak-by test. All back three cylinders held air, but I could hear air escaping past each cylinder’s rings with equal intensity. One of number six’s valves (intake, I think) was stuck open a wee bit at first application of air, and responded quickly to three light taps with a small hammer sealing with no blow by. I performed this test with manifolds removed enabling both feeling for air movement within head ports and listening via hose to ear for air leaking. As for number six stuck open, I don’t know if it was previously stuck, or if a chunk of carbon knocked loose from poking around in port becoming lodged under its seat while partially open. Because of carbon build-up and sticking number six, I will run some decarbonizer through the carburetor after later today. By the way, new engine mounts plus 1/8†shim under driver’s side provide at least ¼†header clearance over adjustment screw on top of power steering box. |
|
| Page 2 of 3 | All times are UTC-07:00 |
| Powered by phpBB® Forum Software © phpBB Limited https://www.phpbb.com/ |
|