| Slant Six Forum https://slantsix.org/forum/ |
|
| update on my recent build https://slantsix.org/forum/viewtopic.php?t=49872 |
Page 1 of 1 |
| Author: | kielbasa [ Sat Sep 22, 2012 3:43 pm ] |
| Post subject: | update on my recent build |
225 .060 over Oregon cam #125 7.8: 1 c/r I have done 500mi oil change and valve adjust And I just hit 1180mi decided to do a compression test to see where I'm at. All plugs look good. #1 seemed a little more lean then the rest, which I expect with the longer intake runner, but #6 seemed normal. #1 134 #2 133 #3 132 #4 130 #5 129 #6 131 This was checked while hot after a 15 mIn drIve. I'm guessing as motor cooled each cylinder dropped a point or 2? Whole process took me a good 30min. Or is that not a significant amount of time to cool and drop #s Motor runs great little shakey when cold I'm gonna try to change out carb gaskets I think I'm getting a small intake leak from there. Only complaint is I think the damn oil pan leaks only on the very rear half where it bolts to the main seal cap. Or it could be the main seal it self. It's not pouring but definitely gets the rear of the pan/trans/dust cover wet and marks it's spot. |
|
| Author: | tlrol [ Sat Sep 22, 2012 5:30 pm ] |
| Post subject: | Huh... |
Compression figures always make me scratch my head. I imagine that the raw number is never as important as the consistency, but your numbers are lower than my Slant has, by about 20 psi. Of course it isn't like anyone has a calibration check on a compression gauge. I wonder what thoughts other folks have... |
|
| Author: | kielbasa [ Sat Sep 22, 2012 5:37 pm ] |
| Post subject: | |
I was expecting 150ish numbers. Could it be rings are still seating, or low compression ratio has something to do with it? |
|
| Author: | WagonsRcool [ Sat Sep 22, 2012 6:02 pm ] |
| Post subject: | |
Only a 5psi spread? I can't remember working on a slant with such even compression results. Minor cylinder to cylinder comp ratio or ring sealing variations can easily account for 5psi. (it's usually much newer/modern eng with only 2-3% cyl leakdown that have such even comp results) |
|
| Author: | kielbasa [ Sun Sep 23, 2012 12:22 pm ] |
| Post subject: | |
I'll take it 5psi spread is good then |
|
| Author: | tlrol [ Sun Sep 23, 2012 2:20 pm ] |
| Post subject: | |
150ish numbers are what I would think would be expected. Probably a break-in sort of thing. My 70K miles slant sports 160ish except for one outlier at 110...I consider it a 5 1/2 cylinder motor. It would interesting to plot compression every 500 miles or so on the break in period... |
|
| Author: | Dart270 [ Mon Sep 24, 2012 5:16 pm ] |
| Post subject: | |
Cam centerline and specs will have a big effect on cranking psi numbers. Those look fine to me for that comp ratio, although they could be higher if the cam were in a different spot. 5psi variation is very good. Lou |
|
| Page 1 of 1 | All times are UTC-08:00 |
| Powered by phpBB® Forum Software © phpBB Limited https://www.phpbb.com/ |
|