Paul,
In that case the heads are not as wild as i would have thought, sounds like standard big valve spec with 1.63" inlets and 1.4" exhaust so your engine is almost the same as mine.
In which case I think the carb calibration you have is very close to ideal so the problem must either be fuel delivery or an ignition fault.
Did you set the float levels correctly? they are often wrong straight out of the box and may possibly be causing a problem with fuelling, what fuel pump and pressure are you running, approx 5.5psi is right for the edelbrock.
Double check timing with a decent timing gun that will show initial timing and how the advance curve is working, did you check that the timing marks are accurate, again many are not accurate.
You mentioned adjustability from the cockpit, what set up is this?
Kevin.
Fluffy at 3000rpm
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Hi Kevin
Apologies for not being able to give you the full spec of the heads as this was not supplied at the time of purchase.
I am going to try the pump rod in the middle hole and take the car for a run this evening.
The timimg is set spot on and was done with a very good timing light and checked by MM and my mate Malc who has forgotten more about cars than I will ever know so am confident in their abilities.
The adjustable timing unit is an MSD control module that couples up to the 6AL and the dizzy and can be adjusted easily either 7.5 deg adv or ret.
I use this unit because when I am fully confident that I can get no more power out of the engine in N/A form the nitrous goes in and changing the timing can play a part in et's etc.
As our engine specs are quite close can you tell me what power you are making please.
I have my own ideas/target that I would like to see on the dyno and wonder if I am somewhat optomistic.
Thanks again for your help.
Will let you know how I get on tonight.
Cheers
Paul
Apologies for not being able to give you the full spec of the heads as this was not supplied at the time of purchase.
I am going to try the pump rod in the middle hole and take the car for a run this evening.
The timimg is set spot on and was done with a very good timing light and checked by MM and my mate Malc who has forgotten more about cars than I will ever know so am confident in their abilities.
The adjustable timing unit is an MSD control module that couples up to the 6AL and the dizzy and can be adjusted easily either 7.5 deg adv or ret.
I use this unit because when I am fully confident that I can get no more power out of the engine in N/A form the nitrous goes in and changing the timing can play a part in et's etc.
As our engine specs are quite close can you tell me what power you are making please.
I have my own ideas/target that I would like to see on the dyno and wonder if I am somewhat optomistic.
Thanks again for your help.
Will let you know how I get on tonight.
Cheers
Paul
Have given the car a good run again tonight up the by pass for some open road type driving and then around the seafront again.
The motor is still alittle fluffy but all I have done is adjust the fuel pressure as it was not quite right.
It did make a difference without question and i think that another tweak will get it spot on.
The regulator seems to not adjust smoothly so it could just be that.
I have not tried the rod in the middle yet as I want to try and eliminate items as I go.
The drive has been about an hours worth and apart from a few rattles and squeaks it is a BLAST to drive.
My finger slipped on the exhaust dump switch as I drove past some Saxo Sid's but as soon as I was past them the dumps were shut off
May not get to the 'puter tomorrow as we have to get an emergency job finished by early next week and it is going to be one of those ,whatever it takes jobs again.
Will keep you posted.
P
The motor is still alittle fluffy but all I have done is adjust the fuel pressure as it was not quite right.
It did make a difference without question and i think that another tweak will get it spot on.
The regulator seems to not adjust smoothly so it could just be that.
I have not tried the rod in the middle yet as I want to try and eliminate items as I go.
The drive has been about an hours worth and apart from a few rattles and squeaks it is a BLAST to drive.
My finger slipped on the exhaust dump switch as I drove past some Saxo Sid's but as soon as I was past them the dumps were shut off
May not get to the 'puter tomorrow as we have to get an emergency job finished by early next week and it is going to be one of those ,whatever it takes jobs again.
Will keep you posted.
P
Paul
Im a big fan of the edelbrock 1404 carb but have to admit it took me a while to get things spot on. With my 4.6 I went down a size on the secondary jets.
One thing I should point out is that if you extend the accelerator pump arm you effectiveley shorten the stroke. For a bigger squirt move the rod inwards. (mine is set on the outside 3rd hole).
I have made quite a few modifications including removing the choke flap and the part of the airhorn that the flap sits on to smooth airflow into the carb. Also I have a double entry fuel inlet (one each side) with high flow float needles and seats.
I would say that mine feels as crisp and smooth as an injection setup.
Keep experimenting youll get there in the end.
Mark
Im a big fan of the edelbrock 1404 carb but have to admit it took me a while to get things spot on. With my 4.6 I went down a size on the secondary jets.
One thing I should point out is that if you extend the accelerator pump arm you effectiveley shorten the stroke. For a bigger squirt move the rod inwards. (mine is set on the outside 3rd hole).
I have made quite a few modifications including removing the choke flap and the part of the airhorn that the flap sits on to smooth airflow into the carb. Also I have a double entry fuel inlet (one each side) with high flow float needles and seats.
I would say that mine feels as crisp and smooth as an injection setup.
Keep experimenting youll get there in the end.
Mark
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CastleMGBV8
- Top Dog
- Posts: 2334
- Joined: Sat Aug 18, 2007 5:09 pm
- Location: Sidcup, Kent, UK
Paul,
Something worth checking and easily overlooked is that the plug leads for cylinders 5 & 7 must be well seperated in the combs as these fire close together, and you can get crossover and missfiring with resultant rough running and loss of power.
As to power output, I would suggest around 1 BHP per cubic inch for a fast road tune Rover V8 so approx 265 BHP, be interested to hear what it produces when you get on the rollers.
Have you had the plugs out to check that they are clean and all roughly the same colourwise?
Kevin
Something worth checking and easily overlooked is that the plug leads for cylinders 5 & 7 must be well seperated in the combs as these fire close together, and you can get crossover and missfiring with resultant rough running and loss of power.
As to power output, I would suggest around 1 BHP per cubic inch for a fast road tune Rover V8 so approx 265 BHP, be interested to hear what it produces when you get on the rollers.
Have you had the plugs out to check that they are clean and all roughly the same colourwise?
Kevin
Hi Kevin and Mark
I am going to adjust the fuel pressure again tonight and see if that does make a difference.
I have checked the plugs and they all appear to be the same colour so i guess all is well there.
With regard to the leads being close together I have spaced them as apart as I can in my application.
I know that just a bit of fettling is probably all that is required to get the motor pulling strong across the rev range and that I will get it sorted but just having you guys at the end of the computer is such a help.
After all as Muscle Manta says " He's just a simple Jannor and needs things explaining slowly to him"
Thanks again gents,I will keep you posted.
As an aside,Mark do you have any photos of your dual inlet set up that you can post up please?
Cheers
Paul
I am going to adjust the fuel pressure again tonight and see if that does make a difference.
I have checked the plugs and they all appear to be the same colour so i guess all is well there.
With regard to the leads being close together I have spaced them as apart as I can in my application.
I know that just a bit of fettling is probably all that is required to get the motor pulling strong across the rev range and that I will get it sorted but just having you guys at the end of the computer is such a help.
After all as Muscle Manta says " He's just a simple Jannor and needs things explaining slowly to him"
Thanks again gents,I will keep you posted.
As an aside,Mark do you have any photos of your dual inlet set up that you can post up please?
Cheers
Paul
-
CastleMGBV8
- Top Dog
- Posts: 2334
- Joined: Sat Aug 18, 2007 5:09 pm
- Location: Sidcup, Kent, UK
Paul,
Just to be clear 5 & 7 should not be next to each other as it can cause the symptoms you have described.
My Rover 3500S came from the factory with the 5 & 7 leads next to each other and it took the dealer who was not familiar with Buick V8 engines months to sort out. I think Rover eventually asked Buick what was causing the problem!
Kevin.
Just to be clear 5 & 7 should not be next to each other as it can cause the symptoms you have described.
My Rover 3500S came from the factory with the 5 & 7 leads next to each other and it took the dealer who was not familiar with Buick V8 engines months to sort out. I think Rover eventually asked Buick what was causing the problem!
Kevin.
-
simontwithers
- Newbie
- Posts: 29
- Joined: Thu Jul 31, 2008 9:44 pm
- Location: Leicester UK
If the car is hitting a wall at 3000rpm and wont go any further, my guess would be fuel pressure. If this problem has occurred over time, i'd check filters and lines for crap including the intank strainer, and then prove the pump delivery by seeing if the pressure drops off whilst on the move.
My approach to problem solving, is one thing at a time, starting with the simplest.
If it makes you feel better, im having V8 problems too.
http://www.v8forum.co.uk/forum/viewtopic.php?t=7685
Cheers
Simon.
My approach to problem solving, is one thing at a time, starting with the simplest.
If it makes you feel better, im having V8 problems too.
http://www.v8forum.co.uk/forum/viewtopic.php?t=7685
Cheers
Simon.
There's no turning back now, I've finished being nice with this engine.
Hi All
Have found some time to have a look at the carb tonight and I have been telling porkies!
The springs I have in on the rods are the orange ones.
MM has a comprehensive calibration kit and I will ask him to send me down the silver springs and I will give those a try.
As an aside I gave the car a run a couple of nights ago and when I gave it the normal throttle it stuttered and then all of a sudden it seemed to clear and shot off pretty quick.
Now this could have been just a bit of crud in one of the jets and it has self cleared in which case problem solved but I still want to give the silver springs a go.
Mark,I have removed the choke and other items as per your photo and ask whether you blocked off the holes for the shaft that runs through over the secondaries or have you left them open to the atmosphere?
They are clearly below the air filter housing and I think they should be blanked off but will bow to your greater knowledge.
Thanks for the help guys.
Cheers
Paul
Have found some time to have a look at the carb tonight and I have been telling porkies!
The springs I have in on the rods are the orange ones.
MM has a comprehensive calibration kit and I will ask him to send me down the silver springs and I will give those a try.
As an aside I gave the car a run a couple of nights ago and when I gave it the normal throttle it stuttered and then all of a sudden it seemed to clear and shot off pretty quick.
Now this could have been just a bit of crud in one of the jets and it has self cleared in which case problem solved but I still want to give the silver springs a go.
Mark,I have removed the choke and other items as per your photo and ask whether you blocked off the holes for the shaft that runs through over the secondaries or have you left them open to the atmosphere?
They are clearly below the air filter housing and I think they should be blanked off but will bow to your greater knowledge.
Thanks for the help guys.
Cheers
Paul
