Breaking in New Engine, Leaks...crankcase pressure? |
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Breaking in New Engine, Leaks...crankcase pressure? |
BeatNavy |
Sep 6 2019, 03:06 PM
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#1
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region |
The last week or so I've been breaking in a new engine I built last winter and finally manage to install a couple of weeks ago. I'm pretty happy with how it pulls, and after a LOT of fiddling with the MPS and timing I think I've got it where it will start right up, idle cold (barely), idle nicely when warm, and run with nice cool head temps. I do seem to have a slight bit of ping/detonation under load around 2800 to 3000 RPM, so I guess I need to play with timing a bit more.
I am much less happy with the oil leaks. I know building a leak-free Type IV is a challenge, and given this is my first effort, I didn't expect perfection. But right now it's leaking pretty badly in a couple of places: out of the transmission weep hole (probably RMS, I guess), somewhere around oil filter console and/or pressure relief valve, and, surprisingly, what seems to be sort of spraying out and around oil filler neck. Here I need help from the World; I see a combination of three possible causes for this many leaks (when I otherwise took my time and tried to follow guidelines, using Jake's recommended sealants): 1. My own inexperience 2. Too much crankcase pressure from rings not seating yet 3. Too much crankcase pressure from no head venting. Here are some details on build: 2056 with 9950 Cam using D-Jet Brand new AA Heads built by HAM, and Len sealed up the vents 96mm KB Pistons with Hastings Rings 8.6 CR A couple of notes: I didn't gap the rings per Jake's philosophy that crankcase pressure is what causes oil leaks, and the rings come properly gapped. Also, Len (and Jake) don't like head venting for oil flow (so my heads had vent plugged). If I understand him correctly, Len told me the stock PCV vale should provide enough crankcase pressure relief on a street car. RMS is the Sabo brand (the "good" one). Any thoughts on 1, 2 or 3 above? I'm willing to pull the engine and reseal, but I wanted to see if 2 or 3 are possibilities that I need to address. Is the stock PCV valve (which I am sure is not clogged) enough pressure relief? Thanks for any help. |
Superhawk996 |
Sep 18 2019, 03:42 PM
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#2
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914 Guru Group: Members Posts: 5,824 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
In Franks case I assume he is using the lambda to adjust the MPS and not just relying on MPS inductance. That is why I wanted to see his console better. Am I correct - tuning to lambda?
@Frank S |
Frank S |
Sep 19 2019, 01:56 AM
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#3
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Member Group: Members Posts: 135 Joined: 15-April 15 From: Wiesbaden, Germany Member No.: 18,632 Region Association: Germany |
In Franks case I assume he is using the lambda to adjust the MPS and not just relying on MPS inductance. That is why I wanted to see his console better. Am I correct - tuning to lambda? @Frank S I'm tuning for Lambda. But by using the vacuum gauge you have a much better idea what adjustments are needed. Just to provide an example driving up a slight slope in 4th gear with contstant throttle at 4000 RPM, I thought I might be already in a engine load situation where the full load diaphragm is active, but with the Vacuum gauge you can clearly see, that you are still far away from the transition point (so it's still the main mixture screw sou have to adjust). As I also have more than one MPS I measured the values after final tuning, like this it was easier to adjust the other MPS units. |
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