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Edelbrock/Offenhauser adapter plates

Posted: Fri Jun 05, 2009 7:02 pm
by Richard P6
My Edelbrock 500 sits on an angled adapter plate which makes it lean back a little.

Image

I have to assume that this plate is designed to make the carb sit flat when the engine sits at an angle? I am considering removing it and fittting a flat heat insulation adapter instaed as the car refuses to start when the engine is hot - I think the fuel is evaporating from the carb.

I don't want to use both as there will probaly be bonnet clearance issues.

Do I really need this angled plate?

Posted: Fri Jun 05, 2009 7:33 pm
by ged
Hi Richard P6,

I think the angle plate was for 4WD applications. I've got mine bolted straight to the manifold & have no problems with it.

Ged :D

Posted: Fri Jun 05, 2009 8:12 pm
by RoverP6B
Hello Richard,

How is everything going?

I have never worked on a Webber, so I could be speaking out of turn here, but I feel at the very least that you want to use a phenolic (or similar heat resistant material) spacer between the underside of the carburettor and the manifold. A flat one by all means.

All the best,
Ron.

Posted: Sat Jun 06, 2009 12:09 am
by ppyvabw
You don't really need the angled plate but it is better to have the carb as level as possible. My engine doesn't have one because of bonnet clearance issues so it is tilted forward. What happens is the engine floods during hard breaking or cornering, even though I have adjusted the float levels slightly.

I also have the heating problem and it's a pain in the arse but I don't have room for a spacer. I considered making an insulating spacer from printed circuit board material but I'm not sure how effective it will be at insulating and I have never got around to it.

Another thing I will say, and I may be speaking out of place here as I know it is often done the same was as you picture, but I would move your throttle return spring. My dad has always told me that the return spring should be as much in line with the throttle cable so that it exerts as little force on the thottle spindle and it's delicate bearings as possible, as it has to be a fairly strong spring. Mine is attached to that conveniant little hole right next to where the cable is attached and is pointing forward. Not sure what other peoples opinions are on this, tis just my humble opinion. From what I can make out, you have the offy dual port which is the same as mine and depending on how thick any insulating spacer will be, you'll have to carve off that little hole at the bottom as I did on mine; it fouls the manifold. Probs not an issue with a thick spacer as you have now.

Posted: Sat Jun 06, 2009 8:19 am
by bones
Hi, i use a angle plate on mine and have had no problems with it, i just got in from work so i could be seeing things, but the plate looks like it is the wrong way round, is the thickest part facing the bulk head,?? :? rich

Posted: Sat Jun 06, 2009 10:05 am
by mgbv8
I've never had this hot start issue with mine either. You can either fit the phenolic plastic spacer or, if clearance is an issue, I think the Mr Gasket multi layer setup is better.
The kit consists of 3 fibre gaskets and two ally heat sink plates which are bigger than the gaskets so they act like cooling fins on a bike engine. You just fit gasket, plate, gasket, plate and gasket. You may need the longer stud kit too.

I just got one for a mate and he's happy with it as it solved a problem for him and its half the thickness of the plastic one.

Posted: Sat Jun 06, 2009 11:33 pm
by ppyvabw
bones wrote:Hi, i use a angle plate on mine and have had no problems with it, i just got in from work so i could be seeing things, but the plate looks like it is the wrong way round, is the thickest part facing the bulk head,?? :? rich
No mate, it's the right way round, The manifold generally is lower at the front in these cases so the thick part goes to the front. His throttle cable is coming from the opposite direction as it should and I am quite sure he has his carb the right way around :lol:

Posted: Sat Jun 06, 2009 11:35 pm
by ppyvabw
mgbv8 wrote:I've never had this hot start issue with mine either
That's interesting because with mine it can vary. After a service with new plugs etc...it can be fine, or sometimes it won't run at all whilst hot in traffic. I think adjusting the carb well can help a lot.

Posted: Sun Jun 07, 2009 10:00 pm
by Richard P6
Thanks all

Everything's going just fine thank you Ron.

I will get one of these Mr Gasket 97 1/4" heat insulation gaskets (thank you mgbv8 - does £18.50 inc. seem reasonable?)) and give that a go. If I leave the car for an hour or so after a run, it will not start, but if I turn the ignition on and leave it on for a while before starting the car, it will start ok - the facet has obviously filled the carb back up.

I could just leave the igntion on for half a minute or so, but the heat can sap the power so anything I can do to reduce it would be good. The heat seems to be less now that I have farte.... ermmm... adjusted the carb anyway - see my other post under engines - 4L power output.

The thick end of the wedge is at the front btw.

I don't have any problems with the angled plate Bones, just wondered if I needed it as it does angle the carb backwards, and pushed the front of the 14" filter up rather high.

I will have a look at the throttle return as soon as I have sorted a few other things - thank you ppyvabw. I don't suffer from problems with hard braking and cornering as I have a P6 which is just a road car and will not be raced, and doesn't go round corners anyway :?

Posted: Mon Jun 08, 2009 1:25 pm
by jefferybond
Richard P6 wrote: I don't have any problems with the angled plate Bones, just wondered if I needed it as it does angle the carb backwards, and pushed the front of the 14" filter up rather high.
I've never run one, and my weber carb is angled forward as a result, but never had any problems.

The forces you get when accelerating and braking will far outweigh the effect the leveling plate has anyway, so I don't really see the point of them. As long as the float levels are set correctly you'll be OK.

Jeff

Re: Edelbrock/Offenhauser adapter plates

Posted: Mon Jun 08, 2009 6:09 pm
by Paul B
Richard P6 wrote:My Edelbrock 500 sits on an angled adapter plate which makes it lean back a little.

Image

I have to assume that this plate is designed to make the carb sit flat when the engine sits at an angle? I am considering removing it and fittting a flat heat insulation adapter instaed as the car refuses to start when the engine is hot - I think the fuel is evaporating from the carb.

I don't want to use both as there will probaly be bonnet clearance issues.

Do I really need this angled plate?
You may find it leans forward a little too much if you take the plate out completely. I guess you'll have to make the decision which is closest to the idea position.

Remember, your studs will be at a funny angle if you remove the tapered spacer, assuming they pass all the way through from the manifold.

You can stick a phenolic spacer in a lathe and spin it off to the tapered angle if you really need to. A four jaw chuck and some careful measurement. Or a milling machine.

Posted: Thu Jun 11, 2009 10:53 am
by Richard P6
I have done some careful measuring and find that the carb angles back at 2.8 degrees.

Is there a 2 degree plate available?

I want to put the 1/2" Mr gasket heat insulating adapter and don't really have the room so the plate will have to go. If I get any problems I can always put it back on, and only use half of the insulator (It comes in pieces), or have it machined down somehow. I do live in Sheffield and if I can't find an engineering company here, where can I find one?