madkaw

Interesting

https://images.app.goo.gl/s7MedL1SofYUqDMXA Set up has not changed from the last motor . Motor swap only . PCV is basically centered or even biased towards to front runners. I would also think #4 would be worse in that case .

I think it’s one cylinder supplying the oil and it’s being dispersed into the other two because of proximity of the n42 intake .

That’s the question!

Okay - turns out I have an oil issue . Oil is getting into to cylinders 4-6 , progressively worse from 4 on . The oil is diluting the charge and causing a misfire - especially in 6. 4&5 seems to be able to burn it off . I removed the intake to check for vacuum leaks to find an oily film in the runners 4-6 . Runners of intake and head both had oil film. First suspect was/is the valve stem seals. I tried a different kind on this build vs my L24. Visually they looked fine . They took a lot of persuasion to install and thought maybe I used too much . Last seals were a Ford seals , which were difficult because they are finicky as hell to install. Actually replaced #6 seal while head was in motor - ran motor and still have same results . Not being able to pin this down I decided to pull the head and look at the guides and anything else . Getting good at this now I guess - 1 hour later the head was on the beach . But no smoking gun found . I ordered more seals anyway. Decision time now . Do I go deeper and pull pistons or throw all new valve seals on and reinstall head and keep fingers crossed ? I was getting ready to leave town and really wanted an answer so I dropped the pan and pulled 6. Still no smoking gun - as far as my experience(novice) eyes can tell. Got on the phone to my machinist - but didn’t hear back yet. My inspection was very quick , so when I’m back in town I will scrutinize closer . Just trying to determine source of oil . I was expecting to see a collapsed expansion ring or another failed ring . There was marks on the bores on the thrust side that were fairly significant visually , but nothing you could feel. I have an extra assembled f54 flat top short block sitting there untouched by amateur hands with 110k miles with perfect wear in the bores . Also pulled a couple of bearings and everything looked spot on. Depending on what I find or not find it might be the next plan. With the head off it makes assembly decision equal. Though this is frustrating , the hobby of engine building will have these outcomes I guess . Not being a stock engine makes this more of a challenge . Missing the L24 right about now because I enjoy driving my car - a lot ! I was hoping for more engine swap and tune - not engine swap and troubleshoot . Hopefully I learn from my mistakes

Maybe I’ll sneak in there too with a fresh motor - if I ever get the beast to stay together - lol

There’s also the option that the machinist used bronze inserts vs knurling the guides and they were/are too tight. Maybe material from wearing on the inserts ruined the seals ? Several possibilities

I doubt a seal would stick a valve under running conditions . Does sound like the oil burn is a valve seal though. This is a problem I’m having now is finding the source of oil. Like you said , a leak down test won’t help find it.

There’s no specific numbers I can brag on , but there’s no contest , especially if you want to run a performance cam or performance engine . I run 45 degrees at cruise and can idle at 18 degrees . You can’t hardly get a dizzy to do that since the vacuum advance is linked to the total advance . Cam sensor really helps for smoother idle and getting that last % of precision from EFI .

I would argue the statement of probably not better power . Timing control is a big part of these motors . To have full control of timing in any load situation is a far and above the compromise of a dizzy - however it might be recurved . I think it’s safe to say power improvements are about guaranteed . Cam sensor is nice , but not necessary . I’ve run years without it .

Well you’ll need a way to control the spark - ECU . Then you need a way to tell the ECU crank position . Then you can do what you want . The options are many .

With 3.90 gears I drive around town in third gear with my TEP lightened flywheel . That was with a 2.4 with a 490 cam. If your engine is strong with those gears you will be fine.

I realized after rereading the thread that this is an untouched used bottom end - so your numbers are healthy for sure . I would be happy with the vacuum readings for sure . I have a 54 block with 110k miles that I need to put a head on . I don’t plan on touching it either since the bores look perfect .

I forgot to add that the other good thing was my cable linkage has been flawless so far - but I probably jinxed myself now -lol

It’s a bit contradictory that you have that high of vacuum numbers but 12% loss on leak down? My engine runs 10 at idle but only 3-5% leak down per cylinder . Plugs don’t look terrible, maybe still burning of residual oil?