madkaw

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?

Not yet . Put everything back together and drove it and she ran good . Got back home and noticed a puddle of oil under the car after parking . I caught the oil pan seal putting the cover on and tore it. So off with the oil pan . Today I drove around and noticed the engine wasn’t building temp. I could hear the fan still turning hard when the engine was cold. Checked to find my clutch fan had gone bad. I’ve had this a long time so I can’t complain too bad - but damn it! i ordered a new clutch. Currently the engine struggles to get to 170. It has always ran right up to 180 and stayed . Temps dropped around here but I think the stuck fan is prolonging warm period to the point that it’s showing on the plugs - but there’s more. THEN I drove it some more to find my brakes were weak. Checked out my vacuum was low - why? Eventually found PCV elbow was torn around the clamp . Now troubleshooting some dirty plugs on 5&6. Thought the worst - HG- but engine leak down test, coolant pressure test, vacuum test are all good. So at least the long block is sound . Power is great, but could be better . Last time I had the mysterious miss it was my fairly new plug wires were bleeding over to each other . This seems similar , but not a dead miss, just carboned plugs . I think I knee jerk reacted to the last issue and went too cold on my plugs. I have 8’s in there now to compensate( at least I thought) for the increased CR. I am putting 7’s back in for now and maybe I’ll find my way back to 6’s yet. I’ll run the 7’s and see if that makes a difference . Good things? The new CV axles are great. My clutch MC fix transformed the shifting experience of the car . It lightened the pedal pressure by 25%.

I just picked up some 1k resistors . My circuit is not set up correctly from what I read . It needs a pull up resistor and the pots adjusted before I can try mine . Waiting on a knock sensor kit before I break into the “box” to do that .

Thanks - tested good?

Question regarding the cam sensor . Since my pigtail came as a kit I had no ID on colors and thus no idea on pin out. Have you got yours working or do you know the pin out for the 3 wires? thanks

I believe Chrysler is the closet match . What was the final word on the head? Sounds like it needs to resurfaced . Some warpage and corrosion could lead to seal issues. He shouldn’t take enough to affect anything including timing chain .

I thought MSA was selling an updated version. Better than the old Precision type , but not sure on this .

I would drain coolant , and use a drill bit or mini file to clean hole and rough insides of hole if you can. Blow it out good and follow instructions with JB. Drilling and tapping would work , but maybe feel more comfortable not drilling . You won’t know if you drill into a completely open cavity or partial which would make tapping a little harder. There’s not much pressure there so some kind of epoxy would work. Also heat wouldn’t be bad since it’s a coolant passage . Just my thoughts

JB Weld it . Prep is key .

Well this build is testing my endurance . Got it up and running and noticed coolant coming out the alternator bracket bolt . Tore it back down to find a failed -new- gasket . Material was thin around that particular hole and I guess it wouldn’t hold. First time for that ? Good news is the motor sounded nasty! My neighbors got to hear open headers for a minute - ?

Back in the hole. Worked on getting my cable throttle hooked up. Pretty stoked the way it came out , pretty much invisible! So glad to be done with the linkage . I went all the way to the pedal too. Feels silky smooth. Now I can completely shave the intake if I want .

Yes

Ideally yes . It also seems odd to me and I am going to re trace my steps again tomorrow . As I said I have quite a bit shaved off the head and .005 off the block , so that would add slack. Even knowing that I still scratch my head a little. I even have the shiny links to reference and I also counted pins .

About a day away from MN/47 part 2. Just finished adjusted chain guides and tensioner to take up some slack! I gained about an 1/8” or so on the chain tensioner which meant the plunger wouldn’t be hanging out as far. I probably have about .030 removed from the total distance , so the slack was real. It actually seemed more prevalent then my L24 set up where I had as much as .050 removed. This time around I’m installing my newly acquired G- Force T-5 . It has a McLeod hydraulic TOB , we will see how that works . Also bought these sweet CV axles from Datsun Garage. Very nice pieces . This might be a whole new driving experience ?

Budget in another 10$ per rod for sizing. You need to resize the rid big ends if replacing with ARP. Cutting the head face is a straight forward process. It’s not risky , anymore risky than not resizing rod bolts or installing valve guides. Head needs to be perfectly flat and a fresh finish also helps guarantee a good seal with the HG. MY 2 cents .