t piece from air filter 88 1.4 Why ???

[glasgowjim]

Why does the 1.4 ltr 1988 340 have a T piece from air filter to rocker cover and the 3rd part of T goes to an open ended pipe that runs to the front of engine ?

It makes no sense to me ?

[volvodspec]

this T piece is from the crankcase venting. the main connection of the T-piece is to inside the airfilter this is to make sure that the crankcase side of the engine cannot build up pressura when the pistons move up en down. if the crankcase venting is blocked; the overpressure in the crankcase can cause the seals to blow out!!

finally, the small connection from T-piece. the hose attached to it is equipped with a restriction that makes sure a hole between 0,5 and 1mm is created, now comes why > the hose is directly connected to below the throttle valve in the carb, if this restriction is not present, a large portion of air is taken out of the crankcase making the seting for the carb very, very wrong!

the way you say it, this hose is not connected.

[glasgowjim]

exactly it is not connected to anything at one end .

One side is onto the T piece he other just runs in a straight line and ends above and just before the water pump.

[volvodspec]

exactly it is not connected to anything at one end .

One side is onto the T piece he other just runs in a straight line and ends above and just before the water pump.

if you take this hose of, can you blow freely through the hose, or is there a noticable restriction still present?

this hose should be connected to the pipe at the bottom of the carb. and offcourse, equipped with the restriction.

DSC00483.JPG (263.3 KiB) Viewed 5848 times

at my left finger to be precise. if you have a manual car, the hose is directly placed at this connetion. if you have a cvt version, there should allready be a hose connected to this pipe, going into a t-piece. one side of the t-piece is for the hose from the crankcase breather, other side goed to top of the 4way valve.

[glasgowjim]

Thanks , I will take a photograph of the carb and hoses tomorrow so that you can see exactly where the hose is not located. If you follow what I mean. Can not do it just now as it is dark outside now .

[glasgowjim]

this photo shows the T piece and pipes

see the blocked off pipe is this ok?

here are a few more can you spot any faults....





comments would be appreciated as although I am a newbie to 340s I have worked on 480's for a while.

[volvodspec]

yep that's not where the hose should go..

it needs to go to the other side of the carb, to the t-piece.

what is connected to the pipe from my picture above?,. can you make a pic from the other side?

[glasgowjim]

the extra pics..

[glasgowjim]

Ah I get it now so the pipe with the bolt stuck on the end should run to the T piece and there should be a constriction in the pipe to reduce the diameter.

Dank U

[volvodspec]

alstublieft graag gedaan

(you're welcome )

[glasgowjim]

WOW what a diference the car has acceleration

but it also idles rather high.

Still a quick read in the HBOL and that should be solved.

the restriction that i used had a diameter of 3mm but i was the best I could lay my hands on at the time.

things just get better and better.

[Chris_C]

Awesome, I'd imagine that now the breathers are plumbed in correctly, the idle and poss mixture are way off. Idle mixture setting on these is no where near as hard as most, I do it by ear, fiddle both idle speed and idle mixture until the engine sounds at its best (normally, fiddle mixture, back idle down, fiddle mixture, back idle down etc) then back the mixture quarter of a turn leaner from best sound. Colourtune etc works, as does asking your local friendly garage to borrow their meter!

3mm restriction should be fine, thats roughly same as the stock one.

[volvodspec]

3mm restriction should be fine, thats roughly same as the stock one.

uhm, it's 3times bigger diameter than original, roughly 10x the flow.. i'd rather wait till a 1mm restriction is applied before screwing around with the mixture, but i do agree that the mixture isn't right at the moment..

with a 3mm restriction there is still way too much added false air for the mixture and you won't get optimalized result with a 3mm restriction

[Chris_C]

Ah, ok, my memory is fading then! Listen to the man above Jim, as he says, mixture should be set when everything is correct!

[glasgowjim]

Solved the problem of finding a 1mm restriction found a shimano bike gear cable outer just the right size inside and out so cut a piece off and viola the restriction is now the correct size and in place