INTAKEMANIFOLD PICTURES

[man-of-war]

This is what the michanic did to the intake.what purpose does this surve? and the intake riser whats its purpose?<br /><br /><br />

<br /><br />

 

[lowshovel1]

Re: INTAKEMANIFOLD PICTURES

looks like he removed some casting burrs,in an atemt to get better flow.

 

[Boomyal]

Re: INTAKEMANIFOLD PICTURES

Looks like he was trying to equalize the fuel flow between cylinder banks. Did you ask him about it?

 

[ron7000]

Re: INTAKEMANIFOLD PICTURES

looks like the intent was to maximize flow, but considering the carb throats are smaller...<br />

<br /><br />you might need to kill your mechanic.<br /><br /><br />or he was trying to lighten the weight of the boat.

 

[man-of-war]

Re: INTAKEMANIFOLD PICTURES

no i never ask about that.how could i repair that ? Would JB WELD work? or should i get it welded? thanks

 

[4.3sunbird]

Re: INTAKEMANIFOLD PICTURES

It will be fine <br /><br />it helps clean up idle by evening out some pulses in the intake .. can also help in higher rpm hp <br /><br />that small of a cut I'd say will help smoothen the idle more than anything else

 

[TilliamWe]

Re: INTAKEMANIFOLD PICTURES

If the notch is what you are talking about, some, if not most of it, was there already. It's fine. The spacer is for two things. It's to adapt a squarebore carb (Holley type) to a spreadbore manifold (Q-jet). Also, the increased height might help produce some torque, kinda like a "hi-rise intake manifold".

 

[ron7000]

Re: INTAKEMANIFOLD PICTURES

<br /><br />didn't you have problems with fuel in the oil?<br />it would not surprise me for a mod like this to cause fuel to puddle in the intake at idle. Not saying this is the cause, but I know it certainly won't help. It has nothing to do with pulses in the intake nor would it help with higher rpm or hp. If anything the disruption in airflow would choke the airstream and reduce maximum possible airflow and lower your wide open throttle rpm, not increase it.<br /><br />I can't view the pics currently because they are blocked on me, but the grinding was done on the intake manifold no? Hopefully it was removed when the grinding was done.<br />The function of a carb spacer if not to provide for PCV is twofold- isolate the carb from heat and straighten airflow below the carb throttle plates when the intake is low profile and flow has to make a right angle turn after the throttle plates to go towards the cylinders. The latter case is what helps torque, throttle response and idle quality because the carb gets a steady consistent signal. Mess with any of this and performance suffers. Other reason a carb spacer might be needed is for clearance of linkage and accessories, in which case you're stuck having to use one regardless if it will help. But a spacer doesn't always help even though the packaging says "increases tq and hp". If the intake manifold is anything but low profile, in other words a high rise type, then you have at least an inch of straight airflow below the carb before it bends off to go towards the cylinders so a spacer would only be what's called a piping loss and then would be the most significant factor limiting airflow, not the bends the air has to make nor any material roughness in the airstream.<br />All this was done on a new engine and it has not run right to begin with? Engines come from the manuf. designed to run well enough, you or your mechanic shouldn't do these things or at least get paid for it and certainly not before the engine is running 100%. Unless you like working on the boat instead of using it.

 

[vettman]

Re: INTAKEMANIFOLD PICTURES

ron7000;Are you saying that if you have a high rise, say edelbrock rpm with 650 holley square bore, a carb spacer would be a waste of money and possible performance? Thanks

 

[ron7000]

Re: INTAKEMANIFOLD PICTURES

probably unless you really need it for heat insulation. I'm not that familiar with edelbrock, what do they recommend? Do they sell spacers to use in addition to their manifold and carb combinations, for reasons other than clearance or adaptation?<br /><br />Ask why would a spacer give any more performance. I would think if they want extra height it would be manufactured that way- in affect it is, that's the "high rise" manifold. The plenum height is, or should be, designed to be optimal for air/fuel mixture, plenum volume, and take advantage of 'pulses' in the intake (acoustic ramming) for the application.

 

[Scaaty]

Re: INTAKEMANIFOLD PICTURES

Edelbrock sells the spacer with their marine carbs. Squarebore to Spreadbore (Qjet). Theirs doesn't cause puddling. My bigger concern is griding on a manifold still on the block, but if done correctly no problem

 

[man-of-war]

Re: INTAKEMANIFOLD PICTURES

Yes, I am getting fuel in the oil crankcase at low idles. So you are saying that I should fill the gap???<br />Thanks

 

[4.3sunbird]

Re: INTAKEMANIFOLD PICTURES

only way gas will get in the oil is by the rings <br /><br />If your air/fuel ratio is right that shouldnt be a problem <br /><br />If you r running pig rich then you will start to notice it<br /><br />If you have a fuel pump on the motor it can leak fuel into the oil<br /><br />most likely you have a bad power valve in that holley carb and causing it to drip fuel at idle<br /><br />or you plain have bad ring seal <br />you get leak down test yet ?

 

[man-of-war]

Re: INTAKEMANIFOLD PICTURES

ill get rid of the riser, and weld that notch that was cut out. ill try any thing to stop that gas in crankcase problem ITS NOT THE CARB NOR THE FUEL PUMP.IT MUST BE THAT NOTCH THAT WAS TAKEN OUT ..OR A BAD HEAD JOB/VALVES

 

[man-of-war]

Re: INTAKEMANIFOLD PICTURES

ITS in the shop.they started on #2, the intake had no leaks but the exhaust did leak a little.That cylinder did have air coming from the air breathers and the dipstick hole.i could not stick around for the complete leakdown session .ill know whats going on tomorrow.

 

[vettman]

Re: INTAKEMANIFOLD PICTURES

Hey ron7000; Thanks for the info.That sounds like it comes from good knowledge and experience.A lot of products claim to increase h.p. and overall preformance, but thats advertisment.This forum is the best source of info. and claims there is thanks again

 

[4.3sunbird]

Re: INTAKEMANIFOLD PICTURES

Id leave the notch cut in the plenum divider<br /><br />bad valve job or anything to do with the intake other than a hole in it which isnt your case will not put gas in the oil<br /><br />a boat motor is going to get more of a gas smell than a car to start with since boats dont have a pcv valve and they also run at lower temps than a car so it has less evaporation of fuel in the oil<br /><br />If he was putting air in the cylinder and it was blowing out the breather tubes ... the rings are not sealed up <br /><br />find someone who knows how to build a performance engine and have them go back thru it .. theres a big difference between rebuilding an engine and building a performance engine

 

[4.3sunbird]

Re: INTAKEMANIFOLD PICTURES

Originally posted by man-of-war:<br /> ITS in the shop.they started on #2, the intake had no leaks but the exhaust did leak a little.That cylinder did have air coming from the air breathers and the dipstick hole.

so are they doing a real leakdown test or just blowing the cylinders up to see where air comes out ?<br /><br />from the sounds of it you might should have just done it yourself

 

[man-of-war]

Re: INTAKEMANIFOLD PICTURES

im paying bristol marine 175.oo to do a leakdown test.thats what i told them,they did have the gague in the boat.i was not allowed to go past a certain point in the hanger so i dont realy know what they did. ill know more tomorrow.with the results.