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> L-jet help #2
bd1308
post Jan 18 2006, 01:31 PM
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so okay...im in the process of putting everything back on that should be on...like head breather stuff and i'm on the crankcase breather right now.

i connect the piping all up, correct stuff with hose clamps. engine idles at like 250 and is obviously running like crap. I open the afm and push the flap more open and tada...it runs better.

i do know I have a little more blow-by than I would like but I am very happy with this engine, and tearing it down isnt an option right now.

so should I just vent the crankcase to atmosphere (which i REALLY dont like/want to do) or what?

I have a new oil filler cap seal installed on it ( the ones from the samba group buy) it seems to fit in this channel thing on the cap istelf, but not at the very top of the cap. what do i do?

b
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Mueller
post Jan 18 2006, 01:47 PM
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basicly it sounds like the engine is getting too much unmetered air (runnning too lean) which of course it does not like.

On my L-jet, I ended up machining some delrin plugs (2) for the intake boot and ran all the crankcase venting to a puke can for the oil residue....I also had a small hose go from the puke can to the airfilter side of the intake to basicly "recycle" the crankcase air that had the benifit of creating a vac. for the crankcase (not much I'd say) and it helped not releasing too much junk air to the atmosphere.

Too much oil in the crankcase air is bad for a few reasons, one it lowers the good clean air available for combustion and two, it adds an oil film to the flapper box and intake track which is not good.

do a search on crankcase venting/puke cans (and here and google) and you'll find some good ideas and designs that can be done dirt cheap.

The L-jet really rocks when you eliminate the unmetered air...at least it did on 2 of my /4 motors (a 1911 and a 2.0)
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r_towle
post Jan 18 2006, 01:50 PM
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on a stock ljet, where is the crankcase venting coming from...I cant remember what it looks like while sitting here...is it coming off the oil breather to the aircleaner??

I dont remember hoses like the head breathers on my 1.7 djet...

Rich
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MartyYeoman
post Jan 18 2006, 01:52 PM
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I second what Mike said.
My car really started running good after I started plugging all
the unnecessary stuff off. EGR and hose to the Decel valve
were the biggest culprites.
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bd1308
post Jan 18 2006, 01:56 PM
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okay.

well the head ports are there...just not hooked up.

I'll do the puke can thing....and then pipe it in to the airbox or something....

and just cap off that port on the intake rubber boot thing....
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JWest
post Jan 18 2006, 02:01 PM
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QUOTE (bd1308 @ Jan 18 2006, 02:56 PM)
well the head ports are there...just not hooked up.

As in plugged or open?

Also check your timing is correct and the vacuum advance/retard (I forget what is stock for 914 L-jet) is all hooked up and working properly. This must be set up just like stock to get the idle in the correct range without having to make other (off nominal) adjustments.
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bd1308
post Jan 18 2006, 02:03 PM
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the head ports are there, and open....just not plugged into anything as of yet. so unplugged as in tapped and drilled and just sitting there open.

its a GA 1.7, the 72 model...premium gas yada yada...

b
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bd1308
post Jan 18 2006, 02:04 PM
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if im running lean, what help is adjusting timing going to make?

b
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rhodyguy
post Jan 18 2006, 02:06 PM
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look very closely at the intake elbow for cracks/splits. you may have to cover the ends, fitting holes and submerge it in water to look for bubbles. splits may not be visible to the naked eye. lmk if you find any problems with yours.

k
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JWest
post Jan 18 2006, 02:07 PM
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QUOTE (bd1308 @ Jan 18 2006, 03:03 PM)
the head ports are there, and open....just not plugged into anything as of yet. so unplugged as in tapped and drilled and just sitting there open.

its a GA 1.7, the 72 model...premium gas yada yada...

b

That's an air leak to the crankcase - it connects via the pushrods tubes to leak to the atmosphere. Plug those (temporarily) or tee them into the breather line near the oil cap (that is how they are supposed to be).
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JWest
post Jan 18 2006, 02:09 PM
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QUOTE (bd1308 @ Jan 18 2006, 03:04 PM)
if im running lean, what help is adjusting timing going to make?

b

You may be chasing a symptom not a cause.
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bd1308
post Jan 18 2006, 02:09 PM
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well the thing is that it runs perfect with that oil filler connection plugged up...

so maybe its what Mike was talking about, the oil smoke and stuff from the crankcase cutting down the available air to spark with....

but the wierd part was I could take the cap completly off and still have the engine running, kinda...

if i kinked the oil filler line....it ran perfectly....

b
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JWest
post Jan 18 2006, 02:10 PM
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QUOTE (bd1308 @ Jan 18 2006, 03:09 PM)
well the thing is that it runs perfect with that oil filler connection plugged up...

so maybe its what Mike was talking about, the oil smoke and stuff from the crankcase cutting down the available air to spark with....

but the wierd part was I could take the cap completly off and still have the engine running, kinda...

if i kinked the oil filler line....it ran perfectly....

b

Right, because you are blocking your leak from the intake to the crankcase and out the heads.
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Katmanken
post Jan 18 2006, 02:12 PM
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What head ports on an L-jet?

None on mine. There was a comment from AA in one of their old catalogs about air leaks in the hose going from the oil fill/breather box and the oil fill cap seal. They mentioned poor idling with air leaks.

So, bottom line, I think yer crancase air leaks need to be sealed to get good idling/running.

Ken
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Mueller
post Jan 18 2006, 02:20 PM
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QUOTE (bd1308 @ Jan 18 2006, 01:09 PM)
but the wierd part was I could take the cap completly off and still have the engine running, kinda...

if i kinked the oil filler line....it ran perfectly....

b

it's called "path of least resistance" (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

with the cap off, the air is going to want to go to atmos. before going into the intake plenum
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JWest
post Jan 18 2006, 02:22 PM
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QUOTE (bd1308 @ Jan 18 2006, 03:09 PM)
but the wierd part was I could take the cap completly off and still have the engine running, kinda...

Let me say this a different way - you already had such a big leak out the heads that the cap makes no difference either way.
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Mueller
post Jan 18 2006, 02:25 PM
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QUOTE (kwales @ Jan 18 2006, 01:12 PM)
What head ports on an L-jet?

None on mine. There was a comment from AA in one of their old catalogs about air leaks in the hose going from the oil fill/breather box and the oil fill cap seal. They mentioned poor idling with air leaks.

So, bottom line, I think yer crancase air leaks need to be sealed to get good idling/running.

Ken

he installed the L-jet on a non-1.8 motor that does have the head vents...the factory should have put them on all of thier engines, but I'd venture to say smog/cost reasons stopped them after '73(??)
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bd1308
post Jan 18 2006, 02:25 PM
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I understand all of this.

are there special additional seals that I need?

the one seal I installed was the one that sealed the cap to the inner part of the oil filler tube....I still need another seal to seal off the lip of the oil filler tube to the oil filler cap. Is this a special seal?

b
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rhodyguy
post Jan 18 2006, 02:33 PM
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does your cap have the o-ring that is on the outer edge?

k
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bd1308
post Jan 18 2006, 02:38 PM
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yeah it does, but it looks crushed or old or FUBAR'd or something....and this flat piece came off of it, rubbery and flat like a pancake....

(IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

b
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