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: 2,933 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. |
BeatNavy |
Sep 16 2019, 02:48 PM
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#2
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Certified Professional Scapegoat Group: Members Posts: 2,933 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region |
Ok, small update. It took a frustratingly long time to get proper exhaust nuts shipped to me. Got the 1/2 side HE installed again after annealing the exhaust rings. Before tightening the nuts up, I tested again with the shop vac technique. I think I'm good with no leaks now.
Took it out for spirited driving. It runs great, although I'm still hearing what I think is detonation under hard load between 2800 and 3200 RPM. My variable timing light is giving me fits -- it won't fire, so I'm using the standard timing light which makes it harder to determine where timing really is (anyone else have issues with a timing light and 1-2-3 distributor?). I'm already running premium fuel with CR calculated at 8.6. Maybe it's something else rattling. Oil temp hit 240+ on my gauge with ambient temps at 90. Although I did buy an IR thermometer. Pointing it at the tuna can sump and it read more like 200+ degrees. It's possible I didn't match the sending unit to the gauge correctly even though I tried to. Should I trust the IR reading more? Lastly, oil leaks are better, although I've got a persistent one that seems to be coming either from the oil filter console or the pressure relief valve. I think I need to reinstall that sealing ring and tighten it up to see if that relieves it. Cold idle is still non-existent. Need to work on that too. Maybe try a different AAR although I know the one I'm using is at least mostly functional. Progress, but it takes a ton of time to fine tune this bugger! |
Frank S |
Sep 17 2019, 02:47 PM
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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 |
Progress, but it takes a ton of time to fine tune this bugger!
[/quote] Went through this with two different engine combos, latest with same combo you are running. Much easier and faster if you measure what you adjust. If you hook up a vacuum gauge, using a T-Piece in front of the MPS and route the hose to the gauge, it's pretty easy to adjust the MPS, as you can clearly see in which region you are running (part load, transition, or full load). Tune for drive ability first, then start to play with idle settings (ignition timing and maybe recalibration of AAR) |
Superhawk996 |
Sep 18 2019, 05:20 AM
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#4
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914 Guru Group: Members Posts: 6,469 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
[quote name='Frank S' date='Sep 17 2019, 04:47 PM' post='2747922']
Progress, but it takes a ton of time to fine tune this bugger! [/quote] Went through this with two different engine combos, latest with same combo you are running. Much easier and faster if you measure what you adjust. If you hook up a vacuum gauge, using a T-Piece in front of the MPS and route the hose to the gauge, it's pretty easy to adjust the MPS, as you can clearly see in which region you are running (part load, transition, or full load). Tune for drive ability first, then start to play with idle settings (ignition timing and maybe recalibration of AAR) [/quote] @Frank S How about posting about your center console setup? Looks interesting. |
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