38dgas

[Guest MrT]

I have put a 38Dgas on my 2ltr pinto. Starts fine, accelerates no hestitation to max RPM but when you go to cruies ie steady 50/60/70 mph etc the engine is 'riching up'

I have had the car on two rolling roads but they have not sorted the problem

I have the following jet sizes

145 main

185 air

145 pump

45 air idle( initial size but drilled to 60)

 

I have checked for float level, looks ok and tested by trying another off another carb, the accelerater pump looks ok and again I havechanged the diaphram.

 

Has any one used smaller jets as an alternative or experienced a similar problem?I don't think the rolling road put the engine under suffcient load to show the problem

 

Carb+2 rolling roads + jets= could have bourght new cheaper!

[Spannerman]

Mr T

 

I have a 38 DGAS carb myself fitted to a 2L Pinto with a Kent FR30

 

You have not said whether its a standard 2L?

 

I dont seem to have any running problems, not sure what jets are in it,

if you really want me to I could strip it down and get the sizes for you?

 

Have you checked that the fuel return is working correctly?

 

Cheers

 

Kevin

[Guest MrT]

Hi Kevin

 

I am running a 2lt standard engine and on the rolling road it was showing 130bhp.

I have blocked off the fuel return pipe from the carb, but when I took the top off there was about 3cm of fuel in the float chamber.

I have changed the fuel return valve for one off a DGAV that was running ok.

If you have a chance and could check the jet size that would be great! I picked the sizes off one of the previous postings.

 

thanks

 

 

Paul

[Spannerman]

Paul

 

I do not follow your statement (I have changed the fuel return valve for one off a DGAV that was running ok)

 

You should have the return from the carb gone back to the tank

as when crusing the fuel pump will supply more fuel than required,

and needs to be dumped back to the tank or it my flood the carb (run rich)

under these drving condition.

 

Kevin

 

ps will still get jet sizes if req.

[Big Jim]

your jet sizes look OK, what air filter are you running? And please DON'T say a bloody pancake one!

[Peter Bell]

Mr T you may try fitting smaller main jets 140 or 135, I have 140 in mine with a 285 cam, flowed head and they still seem a bit rich. My exhaust is as black as your hat (assuming you have a black hat) bear in mind that a DGAV for a standard motor will only have about 130 mains in it. You may have gathered that Jim is not keen on pancake filters, they are fine if they are tall but not possible to fit under a Hoodz hood.

Peter.

[Guest MrT]

I have not put a filter on this carb yet as its been off and on more time than a fidlers elbow.

The return pipe to the tank I have capped off so at the moment there is no return but when I have taken the top off the carb its only about an inch deep in the chamber with fuel. Do you reckon this could cause the problem as the riching up is proportional to the speed ie the higher the crusie the worse the problem, as I have said before if I am running at say 40mph in 4th or 5th its ok but crap at 50,60 70 etc so I presume delivring more fuel.

 

Paul

[Peter Bell]

If you have the float level set up near recommended then don't worry about it, try smaller main jets. Did you take off a DGAV? then try those jets in the DGAS it will show if you are going the right direction even if they aren't a matched pair.

Peter.

[Guest MrT]

Hi Peter

 

I have been down to a Webber Agent specialist in Nottingham this morning, he was fully booked so could not check out the car but I went through the problem, he reckons that there is not enough fuel going in??? on the basis that if the jets were undersize the problem would persist on a full rev range and if you floor the throtle it will accelerate to max |Rpm. I gave him the results of the rolling road print showing it was rich. He said check the plug colour that tells you, fair comment!

I fitted two smaller jets 137s and sure enough the problem perssisted at lower RPM and the acceleration was crap

I have ordered larger jets now but if these don't work he has DGAS's in stock and he can fit a brand new one fully jetted for £200 but I think it might be a trip to the scrappy tomorrow and get a stock unit of a Sierra, I am getting a bit hacked off with it now

 

 

Paul

[Peter Bell]

Hi Paul, I still do not quite understand this, you are saying that the engine is running rich but to solve it you are putting even bigger main jets in. Have you done a plug test as the man suggested? ie. run the engine hard under load with clean plugs, quickly stop and check the colour? Just as another thought, you say you have blocked off the return line from the carb, you haven't got the feed from the pump going into the return outlet side have you? it has a restrictor in it.

Peter

p.s. if you go back to a std. DGAV, at full throttle it will flow almost the same amount of air, as the 38 DGAS (usually) has 27mm venturis and the 32/36 DGAS has 26 and 27mm chokes.

[Big Jim]

There is nothing wrong with the jets that you have in, if the engine is standard, then the idle jets may be a bit big that's all, if you have a 'faster' cam in, they are OK. your problem is somewhere else not the jets!

I would be checking everything else but the carb first. What cam are you running? what timing are you running at?

 

Peter is correct about the DGAV being about the same at top end, but the DGAS wins by a mile on acceleration, when correct.

[Guest MrT]

Hi Peter

 

I know it does not make sense, the read outs were showing rich but dropping the jet size made the car nearly undrivable so I am going to order 150 and 155 jets today and see what happens.The fuel flow is correct. I could not be bothered with it yesterday so let you know what happens next

 

cheers

 

 

Paul