Dumb questions- crab jets and lifter rattle

[motzingg]

Ok two quick and kinda stupid questions, forgive me that i'm 27 and don't know jack about engines designed 30 years before i was born...

Lifter rattle- how much is too much? I had a VW which ran beautifully even though the lifters sounded like they were ready to explode. My truck will rattle every now and then and even change the tone while driving. I'm pretty sure its either one or two lifters that just have bad check valves or something like that, but sometimes it sounds like hell. Today i drove in to work 20 miles sounding like a sewing machine on crack.

Is it going to hurt the engine to run it like that from time to time? Does the marvel-mystery oil trick work (run a bottle with engine oil for a couple days) Do i have to drain and change oil if i do that or can i leave the MMO just hanging out in there?

I also get rattling on all my lifters sometimes on hard stops or turns.. i assume the oil pump is starving, probably not a good windage tray or anything in this old engine. Is that bad? Should i be keeping the oil over filled or something to keep that from happening.




Second dumb question... this is on my 2100 autolite carb conversion. It is running pretty good with the stock 40 jets, but it is rich. It only needs choke on the very coldest mornings and even then only half choke for a couple seconds. I can get 30's or 35's ... how much is changing one 'size' going to affect me? I know the correct answer is 'buy both and try them' but I don't have a feel yet for how much carb jets on a car changes the fueling. On a motorcycle I'd say i'm about 2-3 jet sizes rich.

Going to 30 from 40 (.030" to .040") would be 20% diameter change which (I'd have to do math, eww) could be like a 10% flow rate change? Even going from 40 to 35 seems like a huge jump.

 

[Harte3]

"...i assume the oil pump is starving,..." That could very well be. It might be that the pick-up screen is fouled.

I think the usual procedure for jet changes is to go in two-size increments at a time until your target AFR is reached. If the last change results in an over reach, then go back one size.

 

[THE FRENCHTOWN FLYER]

Ok two quick and kinda stupid questions, forgive me that i'm 27 and don't know jack about engines designed 30 years before i was born...

Lifter rattle- how much is too much? I had a VW which ran beautifully even though the lifters sounded like they were ready to explode. My truck will rattle every now and then and even change the tone while driving. I'm pretty sure its either one or two lifters that just have bad check valves or something like that, but sometimes it sounds like heck. Today i drove in to work 20 miles sounding like a sewing machine on crack.

Is it going to hurt the engine to run it like that from time to time? Does the marvel-mystery oil trick work (run a bottle with engine oil for a couple days) Do i have to drain and change oil if i do that or can i leave the MMO just hanging out in there?

I also get rattling on all my lifters sometimes on hard stops or turns.. i assume the oil pump is starving, probably not a good windage tray or anything in this old engine. Is that bad? Should i be keeping the oil over filled or something to keep that from happening.




Second dumb question... this is on my 2100 autolite carb conversion. It is running pretty good with the stock 40 jets, but it is rich. It only needs choke on the very coldest mornings and even then only half choke for a couple seconds. I can get 30's or 35's ... how much is changing one 'size' going to affect me? I know the correct answer is 'buy both and try them' but I don't have a feel yet for how much carb jets on a car changes the fueling. On a motorcycle I'd say i'm about 2-3 jet sizes rich.

Going to 30 from 40 (.030" to .040") would be 20% diameter change which (I'd have to do math, eww) could be like a 10% flow rate change? Even going from 40 to 35 seems like a huge jump.

Don't rule out other sources for the noise - like pistons or cam gears or trans flex plate.

Can't guarantee that no further damage will occur - it depends on the source.

Don't overfil the engine. Oil pressure is overrated. Once I was at a race and borrowed a magneto to see if a misfire I was experiencing was ignition related. I removed the borrowed magneto and reinstalled my own mag.
"Honey, jump in the car, start it up and hold it above 4000 while I set the total timing". She did and as I was setting the timing I realized there was no oil pump drive shaft on my mag - I had left it in the borrowed one. ZERO oil pressure. Upon teardown no damage was done. But only severe braking or cornering should cause a pressure loss so you may have to address that.

Check the power valve on the carb. It may have failed, making part throttle driving excessively rich.
Is your needle and seat leaking?
Fuel pressure too high?

I'll bet you don't need to lean out the carb. At any rate five steps is a large jump. Flow is more a function of jet area, not diameter. So going from a 40 jet to a 30 jet means you'll reduce flow by about 43% ! - way too much. if you were at 14:1 you'll now be at 25:1. #40 seems awfully small to me anyway.

I love that younger folks are discovering our sixes. And I love that there are still budding gearheads out there. Read all you can, learn all you can, do as much as you can yourself and good luck on your projects.

 

[BIG 6 farmer]

These engines with Factory pistons & lota miles tend to rattle. My bet is some broken, out shape pistons. :hmmm: My 300 six with overbore, and Hyper cast pistons. has a little noise, not bad. Im sure its the fine tooth iron timing gear set (factory parts)

 

[motzingg]

Well, on the way home it was too much for me to stand. I felt like I stepped on my dogs tail the whole way home thrashing her 20 miles on the highway at 60 mph with that rocks-in-a-blender rattle. Really made me sick to hear that, sure sounded awful. It had actually gotten so bad that i could feel the misfire in the one hole.

I stopped into the auto parts store and (as much as i avoid snake oil) grabbed a bottle of Marvel Mystery oil out of desparation and poured it in along with an extra quart or so of Rotella 10/40 for good measure.

about a mile down the road from the auto parts store the lifter floated back up and settled down. I could hear it over about 20-30 seconds slowly float up and get quieter until it smoothed clean out.

I know for sure it is one lifter, i can tell from the sound that its either hole 3 or 4. Based on the periodic sound its only one. I can also tell it is the same lifter each revolution because when there are 2 or more lifters rattling you can hear two distinct sounds or when the oil pressure drops and the pump starves it is a six-per-revolution clatter.


As far as the carb thing, its freshly rebuilt and in mostly good shape... 1.21" motorcraft 2100 (kinda big on a 240) 40 seems small to me too, based on what people have said but it doesn't make much difference filter or not (meaning the filter isn't too restrictive and choking it) and the timing is dead on, maybe a tiny bit on the advanced side. Starts great cold, kinda hard starting warm. All signs point to rich main jet. When it is at WOT there is just no power there, feels like a rich misfire.

The only jets i've seen for sale have been in .005" increments, i.e. .025, .030, .035 etc. I have jet drills and could buy a 30 and drill it up i guess, but ugh i just hate drilling jets.


I really appreciate all the help on here, its awesome having such a knowledgeable group of folks willing to answer dumb questions. Especially having our own resident ford OE insiders!!! I've got a lot of general mechanicking experience and tuning experience, but some of the everyday elements that are common knowledge to any shade-tree guy working on these 'back in the day' completely eludes me.

Sure am liking the old ford though, even with no radio and about 90db of road noise, no power anything, its a lot of fun to drive and the old six is such a lovely sounding engine.

 

[THE FRENCHTOWN FLYER]

I would replace the oil pump and identify the loud lifter if you can and replace it too. Then I would change carbs - something is wrong with that one to run so rich. 2100s are easy and cheap to find.

I have an array of rebuildables for sale, and a selection of jets too - the sizes I will have to check.

2100 C3AF (1963 PASS CAR) 1.01 VENTURII $20 needs one idle adjustment screw
2100 C4AF (1964 PASS CAR) 1.02 VENTURII
for 2 x 2 applications - $75 / pair
2100 DBA-OAB-R 1.02 VENTURII
2100 C7TF (1967 TRUCK) 1.14 VENTURII $25
2100 C6AF – B 1.14 VENTURII $20 needs black plastic choke cap
2150 D8WE (1978 COUGAR) 1.21 VENTURII $25
2100 unknown part # 1.33 VENTURII $30




Ditto on drilling jets - I avoid it if possible. When I do have to I've found the best way is to hold the drill in a hand-held pin vise and put the jet in a slowly spinning lathe, mill, or drill press and drill from the backside outward - opposite of the flow.

PM me if you like.

 

[motzingg]

hmm, i will have to think about that. I would be a lot more apt to jump into a new carb right away if this one didn't run so darn good. I mean all across the board this thing is running perfect, only thing being that it is bizarre rich.

Its kindof odd to me that it came with 40 jets to begin with. This carb has been molested, but not significantly. The screws were a little torn up when i got it, and one was stripped (I cant remember if it was power valve cover or accel pump) but it looked like original jets in it. The idle adjuster needles weren't wallerd out on the seat like often happens, and only a couple minor parts were missing.

I completely forgot, if you remember this is the one that i was asking about the check ball weight, it was missing and i used a nail. I also cut a new sheet metal spreader dingus from a pabst can to go on top of the emulsion bar, halo thingy. If i remember correctly either you or rick had said that if the check ball isn't in there fuel can flow from the power valve into the main jetting... maybe a previous owner jetted it down to compensate for that being missing? Maybe my nail isn't heavy enough?

What was odd to me with the missing parts was that the carb appeared to have lost those parts then continued to be used. It had heavy varnish on top of the jets, and lots of

I hadn't thought of it, because my low and mid is so fat, but I could have actually fattend out the idle to run good and be going lean on top, but since my idle is still so fat, it is starting without choke. I really need to pull the plugs and have a look at them. Its not rich misfiring on the top, but just doesn't respond much past 2/3 throttle. I guess when i'm driving home today i'll see if i can feel the accelerator pump helping me or hurting me in the transient condition.

Having the DS ignition is probably not making the troubleshooting any easier, because that thing will probably light a fire to just about any fuel mixture. If i had wimpy points i'd be more likely to feel the rich misfire, if that is what is going on.





I'll think about that 1.02, it might be worth swapping. I'm getting ready to move right now so the truck is on a 'need to wrench' basis, only mandatory stuff is getting fixed until we get moved, which sucks because i'm leaving behind about 20 bumps in various junkyards in the area here.



As for the oil pressure situation, the gauge is reading dead in the middle, and moving like it should (high when cold, drops when hot, changes based on RPM) but i really need to slap a real gauge on there. Embarrassing that i haven't, considering i have a bucket of gauges at work and plenty of fittings to hook it up.

 

[MechRick]

I stopped into the auto parts store and (as much as i avoid snake oil) grabbed a bottle of Marvel Mystery oil out of desparation and poured it in along with an extra quart or so of Rotella 10/40 for good measure.

about a mile down the road from the auto parts store the lifter floated back up and settled down.

I'm not a believer in snake oil either, but I've used Rislone to quiet a gummy lifter on several occasions. It's the only 'snake oil' I would bet on or recommend to customers. Marvel oil is similar.

My six gets a bit ticky once in a while. I've had two cam and lifter sets in this one. Still noisy, but I don't worry about it. Gives it character like the rattly clutch baskets on my old Suzukis...

As FTF said, if you get one lifter that collapses completely, you should probably identify it and replace it.

 

[motzingg]

Yeah... the passages and check valves are pretty picky about gum and varnish I reckon, and it doesn't take much to keep one from holding pressure. Sometimes a little extra solvent and detergent is probably just the ticket.

Another thing that is bugging me is that I still haven't hooked up that PCV valve, I noticed the last time i had the breather off that there is some milky deposits (i assume light hydrocarbons and oil vapor mixed with moisture from blowby) around the breather. That may be an additional source of oil contamination that I should probably address as soon as possible.

 

[Harte3]

The milky gunk is something that shows up about this time of year and is quite common. Cold starts and short trips are the usual culprits.