Edelbrock Return Spring Bracket... - Page 3 - Chevelle Tech
Engine AdvertisementGeneral Engine Discussion. Advertisement

 2Likes
Reply
 
LinkBack Thread Tools Search this Thread Display Modes
post #31 of 48 (permalink) Old Dec 3rd, 18, 8:14 AM
Senior Tech Team
jeff
 
Join Date: Jan 2008
Location: yukon ok.
Posts: 4,800
Re: Edelbrock Return Spring Bracket...

I think it is the lower RPM he tested at and the large runner heads on the 377" engine.
What I found with the Comp cam ratings is that is about where they make Max HP.
My 268H on the wheel dyno made Max HP at 5700rpm and the 280H in the same 350" made max HP at 5870 RPM

I am limited a bit on cylinder head though 601 casting 305 head with 1.84-1.50 valves.

On my roller 357" the roller is 228 [email protected] .050 .495" lift on 110 LSA it made max HP at 5840 rpm but pulls hard to 7000+

I wonder if your AFR if way off or if maybe the engine is just built tight.
Mine are all on the loose side .0035" piston to wall clearance with cast pistons.
I was 1000 rpm down on a tight engine i had built years ago .0015" with cast pistons.. thing would not get out of it's own way is the way it felt to me..
I will not build another tight one.
But this is old school cast pistons with long skirts and 5/64" rings 620 grit cylinder wall finish.
jeff swisher is offline  
Sponsored Links
Advertisement
 
post #32 of 48 (permalink) Old Dec 3rd, 18, 10:57 AM Thread Starter
Lifetime Premium Member
Brian
 
Join Date: Jun 2003
Location: Mesa, AZ
Posts: 2,870
Garage
Re: Edelbrock Return Spring Bracket...

Quote:
Originally Posted by Tom Mobley View Post
are you dead sure you're checking the vacuum at manifold port, not ported?

something is not right about this.
I plug my vacuum gauge into the hose for the power brake booster. It goes straight to a fitting on the intake itself.

1971 Malibu, factory buckets/full gauges/console, 377 roller cammed small block, Turbo 400, 3.42 10 bolt posi (Buick), - All your base are belong to us.
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ open headers:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ 2.5 pipes + X crossover/18 inch glass packs:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
WakkoWarner is online now  
post #33 of 48 (permalink) Old Dec 3rd, 18, 11:01 AM Thread Starter
Lifetime Premium Member
Brian
 
Join Date: Jun 2003
Location: Mesa, AZ
Posts: 2,870
Garage
Re: Edelbrock Return Spring Bracket...

Quote:
Originally Posted by jeff swisher View Post
I think it is the lower RPM he tested at and the large runner heads on the 377" engine.
What I found with the Comp cam ratings is that is about where they make Max HP.
My 268H on the wheel dyno made Max HP at 5700rpm and the 280H in the same 350" made max HP at 5870 RPM

I am limited a bit on cylinder head though 601 casting 305 head with 1.84-1.50 valves.

On my roller 357" the roller is 228 [email protected] .050 .495" lift on 110 LSA it made max HP at 5840 rpm but pulls hard to 7000+

I wonder if your AFR if way off or if maybe the engine is just built tight.
Mine are all on the loose side .0035" piston to wall clearance with cast pistons.
I was 1000 rpm down on a tight engine i had built years ago .0015" with cast pistons.. thing would not get out of it's own way is the way it felt to me..
I will not build another tight one.
But this is old school cast pistons with long skirts and 5/64" rings 620 grit cylinder wall finish.
I have had this engine since 2007 and it has about 50,000 miles on it. I have not idea if it is tight or loose. The shop that built it is no longer in business due to many customer complaints. When I punch it, it goes and pulls strong.
jeff swisher likes this.

1971 Malibu, factory buckets/full gauges/console, 377 roller cammed small block, Turbo 400, 3.42 10 bolt posi (Buick), - All your base are belong to us.
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ open headers:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ 2.5 pipes + X crossover/18 inch glass packs:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
WakkoWarner is online now  
 
post #34 of 48 (permalink) Old Dec 3rd, 18, 1:04 PM
Senior Tech Team
jeff
 
Join Date: Jan 2008
Location: yukon ok.
Posts: 4,800
Re: Edelbrock Return Spring Bracket...

It is loose by now.
The one I had the machine shop bore and hone I did not specify clearances..Heck I was new at having stuff bored out.

So I was running the 268H and ported and milled 76cc iron heads heads in a standard bore worn out 350" and busted the skirts but that thing pulled hard to 6500rpm.
I drove it 30,000 miles like that and pulled it apart and had it bored and honed.. was .0015" piston to wall and the thing with all the same exact parts except pistons rings now only revved to 5000 rpm after that it nosed over and felt weak.

After 30,000 more miles it was revving to 5500rpm and felt better. still 1000 rpm down from the loose deal.

Next one I built had .0045" then I did a .0035" and it felt just like the .0045".

I put many more miles on my stuff than you, one year I drove 70,000 miles as did the wife in another car.
Well I stopped count on hers at 65,000 miles in 11 months.

Lot of testing happening in a short time you know. Lot of oil changes also.
I found the 268H will rev cleanly to 6500 pretty easy without any feeling of nosing over. In fact at the track the 6500 or 5000 or 5500 or 6000 shift point resulted in only 2 tenths difference.

The 270H was 6900rpm sweet spot. 280H was 7200 sweet spot and 292H was 7400rpm.
This is with small chamber ported heads with 1.94-1.50 valves.
If using smaller intake valve RPM was less and if the port job was not done then you would be down 1000 rpm.

Good shaped intake runners make a huge difference I have found.
jeff swisher is offline  
post #35 of 48 (permalink) Old Dec 3rd, 18, 2:42 PM Thread Starter
Lifetime Premium Member
Brian
 
Join Date: Jun 2003
Location: Mesa, AZ
Posts: 2,870
Garage
Re: Edelbrock Return Spring Bracket...

I do know that from the beginning this engine always pulled strong. The crank and rods are made by RPM (forged 4340 on the crank, and the rods are forged h-beam). The pistons are forged Probe SRS units (12cc dish). Does anyone know if using 1.6 rocker arms affects the overlap on a camshaft??

1971 Malibu, factory buckets/full gauges/console, 377 roller cammed small block, Turbo 400, 3.42 10 bolt posi (Buick), - All your base are belong to us.
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ open headers:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ 2.5 pipes + X crossover/18 inch glass packs:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
WakkoWarner is online now  
post #36 of 48 (permalink) Old Dec 3rd, 18, 5:39 PM Thread Starter
Lifetime Premium Member
Brian
 
Join Date: Jun 2003
Location: Mesa, AZ
Posts: 2,870
Garage
Re: Edelbrock Return Spring Bracket...

I am really wanting to like this Edelbrock, but it still has a slight stumble occasionally from part throttle. I did change out the step up springs this afternoon (I had to scramble to find one of the springs that hold the metering rods to the plunger, as it was already broken when I pulled the plunger out of the carburetor - a local auto shop had one and gave it to me - now I think I need to source one or two and take one to him so he has it).

The accelerator pump is in the middle position. I do have a rebuild kit on the way, so it will get a new plunger (that may be what is causing the issue, since it sat without fuel in it for about a month before I bought it). Once I get that and get the top off, I can check the float levels, put new needles and seats in, and see if there is any crap in it.

I really like the way it pulls at WOT - it just seems to be better than the Speed Demon. 1967 chevelle malibu (Gary) let me bring it by his house last weekend to get a second set of eyes on it to see how the throttle shafts were. When they are open, there really isn't any play in them. So, I think it is just a matter of doing some tuning on it to get it where it should be. The 1411 is 2% leaner than the 1407, according to Edelbrock. If I can't get the slight stumble at part throttle tuned out, would a jump up in squirter size help??

1971 Malibu, factory buckets/full gauges/console, 377 roller cammed small block, Turbo 400, 3.42 10 bolt posi (Buick), - All your base are belong to us.
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ open headers:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ 2.5 pipes + X crossover/18 inch glass packs:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
WakkoWarner is online now  
post #37 of 48 (permalink) Old Dec 4th, 18, 4:19 AM
Senior Tech Team
Geoff
 
Join Date: Mar 2015
Location: Australia
Posts: 1,865
Re: Edelbrock Return Spring Bracket...

Once float level has been verified, use a met rod with a richer power step for the part throttle stumble. Go at least 0.005" richer [ preferably 0.010" ]. If this fixes the stumble, lean out the power step on the rods until you have the rods just rich enough to remove the stumble.

You may also need to increase the nozzle size on the acc pump nozzle. Increase in 0.002" increments. This would be a last resort.

Remember, ALL these carbs are 'universal' fit & it is unrealistic to expect a carb to bolt onto every engine & work perfectly without modification/tuning.....
Gtogeoff is offline  
post #38 of 48 (permalink) Old Dec 6th, 18, 2:40 PM Thread Starter
Lifetime Premium Member
Brian
 
Join Date: Jun 2003
Location: Mesa, AZ
Posts: 2,870
Garage
Re: Edelbrock Return Spring Bracket...

It is also backfiring on acceleration from idle occasionally. I wish that the tuning kits weren't so much money. They really should be about half of what they charge for them.

1971 Malibu, factory buckets/full gauges/console, 377 roller cammed small block, Turbo 400, 3.42 10 bolt posi (Buick), - All your base are belong to us.
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ open headers:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ 2.5 pipes + X crossover/18 inch glass packs:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
WakkoWarner is online now  
post #39 of 48 (permalink) Old Dec 7th, 18, 7:45 PM Thread Starter
Lifetime Premium Member
Brian
 
Join Date: Jun 2003
Location: Mesa, AZ
Posts: 2,870
Garage
Re: Edelbrock Return Spring Bracket...

I got a kit today and put it in - including a new accelerator pump assembly. The floats are adjusted correctly. I found something that was contributing to the throttle not returning to the idle position and corrected that. But, once I got it fired up and took it for a drive, it really isn't any better than it was. It has an off idle stumble that irritates me (it has 35 size squirters in it). So, I am done with it. I will put the Speed Demon back on tomorrow and call it good. I just don't have the patience to keep tinkering with the Edelbrock to make it work. Plus, I am done spending money on it. It will get emptied out and sit on a shelf in my shed.

1971 Malibu, factory buckets/full gauges/console, 377 roller cammed small block, Turbo 400, 3.42 10 bolt posi (Buick), - All your base are belong to us.
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ open headers:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ 2.5 pipes + X crossover/18 inch glass packs:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
WakkoWarner is online now  
post #40 of 48 (permalink) Old Dec 7th, 18, 10:28 PM Thread Starter
Lifetime Premium Member
Brian
 
Join Date: Jun 2003
Location: Mesa, AZ
Posts: 2,870
Garage
Re: Edelbrock Return Spring Bracket...

I took a short video this afternoon with a vacuum gauge hooked up to the manifold vacuum port on the carburetor, just so you can see what the vacuum is at idle in gear.

https://www.dropbox.com/s/2hcu1nsgno...55332.mp4?dl=0

1971 Malibu, factory buckets/full gauges/console, 377 roller cammed small block, Turbo 400, 3.42 10 bolt posi (Buick), - All your base are belong to us.
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ open headers:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ 2.5 pipes + X crossover/18 inch glass packs:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
WakkoWarner is online now  
post #41 of 48 (permalink) Old Dec 8th, 18, 8:09 AM
Senior Tech Team
gary
 
Join Date: Oct 2011
Location: arizona
Posts: 1,095
Re: Edelbrock Return Spring Bracket...

Does it return to idle with the new kit?
1967 chevelle malibu is offline  
post #42 of 48 (permalink) Old Dec 8th, 18, 10:40 AM Thread Starter
Lifetime Premium Member
Brian
 
Join Date: Jun 2003
Location: Mesa, AZ
Posts: 2,870
Garage
Re: Edelbrock Return Spring Bracket...

Quote:
Originally Posted by 1967 chevelle malibu View Post
Does it return to idle with the new kit?
The problem I found was with the s hook on the accelerator pump rod. It was twisted and compressed a little, which was causing the primary
throttle blades to stay open. It seems to return to idle for the most part, but occasionally it will be about 150 RPM higher than it should.
I just don't have the patience to deal with it anymore and I don't want to spend any more money on it. I will just put the Speed Demon
back on today and put the Edelbrock in the shed.

1971 Malibu, factory buckets/full gauges/console, 377 roller cammed small block, Turbo 400, 3.42 10 bolt posi (Buick), - All your base are belong to us.
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ open headers:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ 2.5 pipes + X crossover/18 inch glass packs:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
WakkoWarner is online now  
post #43 of 48 (permalink) Old Dec 8th, 18, 11:31 AM
Senior Tech Team
jeff
 
Join Date: Jan 2008
Location: yukon ok.
Posts: 4,800
Re: Edelbrock Return Spring Bracket...

Man that sucks.. sure looks like a low idle vacuum. I had one car that pulled 5" at idle and I had to add a lot of jet to it to make it happy.
[email protected] .050 cam and 9.0 compression and afr 210cc heads on a 355".
jeff swisher is offline  
post #44 of 48 (permalink) Old Dec 9th, 18, 3:38 AM
Boldly procrastrinating
Tom Terrific II
 
Join Date: Oct 1998
Location: Glendale, Az
Posts: 28,051
Garage
Re: Edelbrock Return Spring Bracket...

which of the scales on that gauge are you reading? I can't bread the labeling much.

seems like it would have about 12-13 vac at idle.

Tom Terrific or Terrible Tom, depending on the phase of the moon, passing cosmic rays or other factors not fully understood except by my wife.
Tom Mobley is offline  
post #45 of 48 (permalink) Old Dec 9th, 18, 11:04 AM Thread Starter
Lifetime Premium Member
Brian
 
Join Date: Jun 2003
Location: Mesa, AZ
Posts: 2,870
Garage
Re: Edelbrock Return Spring Bracket...

Quote:
Originally Posted by Tom Mobley View Post
which of the scales on that gauge are you reading? I can't bread the labeling much.

seems like it would have about 12-13 vac at idle.
If you look at where the needle is pointing, you will see the 0 - 5 - 10 area - that is the vacuum portion of the gauge.

I have decided, however, that I will try the Edelbrock one more time. It just seems to pull harder than the Speed Demon does. I will adjust the accelerator pump rod to the top hole and see what happens. If the off idle stumble goes away, then I will mess with the step up springs to see if I can eliminate the part throttle issue (feels like it loses power). The mileage with the Edelbrock was still around 6.5, but I was getting on it more (because it actually pulls harder when I am in second gear than the Speed Demon did)

I just want to get it sorted out and leave it alone - the Speed Demon seems to develop issues every year (but at least it has no off idle stumble).

1971 Malibu, factory buckets/full gauges/console, 377 roller cammed small block, Turbo 400, 3.42 10 bolt posi (Buick), - All your base are belong to us.
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ open headers:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


My Chevelle w/ 2.5 pipes + X crossover/18 inch glass packs:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
WakkoWarner is online now  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in










Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome