Vintage Oldsmobiles Curved Dash, Limited Touring, Models 40, 53, 66; Series 60, 70, 90

1957 J2 center carb jetting

Old September 1st, 2016, 07:18 PM
  #1  
Registered User
Thread Starter
 
Join Date: Feb 2013
Location: San Francisco area in formerly wonderful California
Posts: 49
1957 J2 center carb jetting

I recall seeing somewhere what the jet size should be on the center carb on a J2 motor but using the search function I cannot find it....anybody??? I was also told the jet size should be increased due to today's gas. Comments???
Thanks.
bspaulding is offline  
Old September 2nd, 2016, 08:13 AM
  #2  
Registered User
 
Tedd Thompson's Avatar
 
Join Date: Oct 2004
Location: Forest Ranch Ca.
Posts: 5,137
What are the symptoms of the engine that make you feel you need to change the carburetor jetting? I have never owned a J2 setup but on all the other cars (2bbl and 4bbl) I have had I've never had to change jets because of to days gas..... Tedd
Tedd Thompson is offline  
Old September 2nd, 2016, 10:20 AM
  #3  
Registered User
Thread Starter
 
Join Date: Feb 2013
Location: San Francisco area in formerly wonderful California
Posts: 49
J2 Carb Jetting

The symptoms are an engine that failed because both head gaskets (Egge) failed and several "experts" are trying to determine why on a fresh engine. (See my other post on 371 engine rebuild with photos).

The gaskets show high heat which caused the fire ring on the gasket to fail. The suspicion was excessive timing but the timing and the distributor were on spec. So the attention was focused on the possibility of a lean situation hence my request for jet size so we can have a starting point.

The jets have been changed as on the first rebuild (lasted 1800 miles and failed because of suspect lifters) the plugs and exhaust showed a rich condition. we went down one size.

The fresh rebuild lasted 30 miles before two blown head gaskets. Both rebuilds had a broken ring lands on one piston on teardown In both cases it was a center piston.

We are sourcing US made forged pistons and all metal gaskets but want to determine if the problem is something wrong in the engine or crap foreign parts.

Thanks for your interest.

Jet size anyone???
bspaulding is offline  
Old September 2nd, 2016, 10:26 AM
  #4  
Registered User
Thread Starter
 
Join Date: Feb 2013
Location: San Francisco area in formerly wonderful California
Posts: 49
Re the todays fuel situation question, The guy who tunes carbs in the SF area says todays fuel needs carbs to be richer so he routinely ads a jet size then tunes the car with an exhaust analyzer. He tuned the engine after the first rebuild adding a jet size---now it was too rich and on these old carbs we really don't know where we are, hence my request for a starting point.
bspaulding is offline  
Old September 2nd, 2016, 01:16 PM
  #5  
Registered User
 
TripDeuces's Avatar
 
Join Date: Jun 2010
Location: Rogues Island, USA
Posts: 3,480
Ethanol makes about a 1/3 less power than gasoline of the same volume so I suppose it does make sense. If your local gas is 10% ethanol then you are running roughly 3% leaner right off the bat. I don't see where going up one jet size could hurt. Since your carb tuner is using an analyzer it should be easy for him. Is he using a Lambda meter or an O2 set up?

Last edited by TripDeuces; September 2nd, 2016 at 01:29 PM.
TripDeuces is offline  
Old September 2nd, 2016, 01:49 PM
  #6  
Registered User
Thread Starter
 
Join Date: Feb 2013
Location: San Francisco area in formerly wonderful California
Posts: 49
jet size

I think Lambda but not certain.

Jet size???
bspaulding is offline  
Old September 6th, 2016, 08:26 AM
  #7  
Registered User
 
Tedd Thompson's Avatar
 
Join Date: Oct 2004
Location: Forest Ranch Ca.
Posts: 5,137
Contact Tony at Ross Racing Engines if anyone knows the jet size he would. They also sell pistons for the 371.... Tedd https://rossracingengines.oursafeserver.com/
Tedd Thompson is offline  
Old September 7th, 2016, 01:23 PM
  #8  
Registered User
 
Join Date: Mar 2008
Posts: 3,468
Original jets were 70026xy, where xy was 58 for center carb in 1957; 59 for center carb in 1958; 59 for front and rear carbs in 1957, 65 for front and rear carbs in 1958. The 70026 portion of the part number indicates the 90 degree entry to the orifice. 70086 would be the tapered entry, for example. If you give us the venturi sizes, we can help you optimize the jetting.
Run to Rund is offline  
Old December 25th, 2017, 05:46 PM
  #9  
Registered User
 
OLDSter Ralph's Avatar
 
Join Date: Sep 2017
Location: St. Paul Minnesota
Posts: 1,140
Any updates on this thread ? What was the final determination ?
Ralph
OLDSter Ralph is offline  
Old December 25th, 2017, 09:53 PM
  #10  
Registered User
Thread Starter
 
Join Date: Feb 2013
Location: San Francisco area in formerly wonderful California
Posts: 49
J-2 carb setting

Well guys, thanks for all your input but my project had turned into the car from hell.

The THIRD engine was installed after a few changes from engine No.2. Roller cam, forged pistons, metal head gaskets, custom cam grind and MUCH attention to why the first two engines went away.

The two main issues found on the second rebuild:

Wrong carb to manifold gasket which caused a huge vacuum leak on all three carbs. It is a wonder the car even ran.

Wrong cam grind which resulted in too high a dynamic compression. The legendary Cam Grinder Dimitri Elgin corrected the cam issues.

Both were resolved and the engine runs great.

Then the car was in a rear end accident when the electric e-brake failed (operator error) and the car rolled backwards into a concrete post. The damage was in the center rear requiring extensive repair and a good used trunk lid. To get the necessary parts I purchased another '50 sedan that was partially stripped but had been untouched in the rear to get the reartrunk support and sheet metal stuff we needed. The parts were only good for patterns so we re-popped a rear trunk support.

So after many delays and repairs, the car is now on the road and very strong. An easy dyno run at 400 miles to 4000 RPM, resulted in 280 hp at the wheels and still climbing. We now have over 1000 miles on the engine and will do a full pull sometime in January. We expect 300++ at the wheels---not bad for a factory rating of 277 at the flywheel.

The dyno guy has a new set of Rochester jets and we will fine tune the jets on the dyno.

I will update when I can put a done stamp on this project...Merry Christmas and thanks again.

Bill---12-25-17
bspaulding is offline  
Old December 26th, 2017, 10:49 AM
  #11  
Registered User
 
OLDSter Ralph's Avatar
 
Join Date: Sep 2017
Location: St. Paul Minnesota
Posts: 1,140
Originally Posted by bspaulding View Post
Well guys, thanks for all your input but my project had turned into the car from hell.

The THIRD engine was installed after a few changes from engine No.2. Roller cam, forged pistons, metal head gaskets, custom cam grind and MUCH attention to why the first two engines went away.

The two main issues found on the second rebuild:

Wrong carb to manifold gasket which caused a huge vacuum leak on all three carbs. It is a wonder the car even ran.

Wrong cam grind which resulted in too high a dynamic compression. The legendary Cam Grinder Dimitri Elgin corrected the cam issues.

Both were resolved and the engine runs great.

Then the car was in a rear end accident when the electric e-brake failed (operator error) and the car rolled backwards into a concrete post. The damage was in the center rear requiring extensive repair and a good used trunk lid. To get the necessary parts I purchased another '50 sedan that was partially stripped but had been untouched in the rear to get the reartrunk support and sheet metal stuff we needed. The parts were only good for patterns so we re-popped a rear trunk support.

So after many delays and repairs, the car is now on the road and very strong. An easy dyno run at 400 miles to 4000 RPM, resulted in 280 hp at the wheels and still climbing. We now have over 1000 miles on the engine and will do a full pull sometime in January. We expect 300++ at the wheels---not bad for a factory rating of 277 at the flywheel.

The dyno guy has a new set of Rochester jets and we will fine tune the jets on the dyno.

I will update when I can put a done stamp on this project...Merry Christmas and thanks again.

Bill---12-25-17

Bill, why a roller cam ? Who ground the cam before and the roller cam you installed ? Do you have a "grind spec" from Elgin ? What rocker arms are you using ?
What pistons did you get and from who ?

Sorry about the misfortune from the "operator error".
Good luck and keep us posted on how things are going.
RALPH
OLDSter Ralph is offline  
Old December 29th, 2017, 04:54 PM
  #12  
Registered User
Thread Starter
 
Join Date: Feb 2013
Location: San Francisco area in formerly wonderful California
Posts: 49
J-2 carb setting

Hey Ralph---

Why a roller cam? 'cause I could and I do not want to worry abut the correct oil to use.

The earlier cam either Fusick or Egge---forget which but Elgin said is was one of the worst grinds he ever saw and may have been the problem all along. The first two engines had blown head gaskets and broken ring lands.

I got the pistons from Mondello and the rockers are stock J-2 adjustable---1.5??

I'll try to attach photos and one of the cam card.20160805_120350_001[1].jpg20160916_113017[1].jpg



20171229_154128[1].jpg
bspaulding is offline  
Old December 29th, 2017, 10:23 PM
  #13  
Registered User
 
OLDSter Ralph's Avatar
 
Join Date: Sep 2017
Location: St. Paul Minnesota
Posts: 1,140
Originally Posted by bspaulding View Post
Hey Ralph---

Why a roller cam? 'cause I could and I do not want to worry abut the correct oil to use.

The earlier cam either Fusick or Egge---forget which but Elgin said is was one of the worst grinds he ever saw and may have been the problem all along. The first two engines had blown head gaskets and broken ring lands.

I got the pistons from Mondello and the rockers are stock J-2 adjustable---1.5??

I'll try to attach photos and one of the cam card.[ATTACH]199567]

Bill, Howdy.
I have been trying to research things. The "modern oils" have presented some problems for older engines. That is one factor that is making me think about a roller cam. Flat tappet cams from a couple of cam grinders has me concerned.
A guy at Ross Racing engines said a 371 had to bee machined to use a roller cam. What did they do on your motor ?
According to NHRA, 1.8 is the rocker arm ratio if I read correctly. Do your valve covers have "bumps" to clear rocker arm adjusters ? Where did you get the adjustable rockers ?
Did you get the pistons from Mondello in Tennesee ?
The nice bore/stroke ratio is another good thing, if "good rods" are used. The engine could spin some RPM's from what I have read.
Thanks for taking the time to answer my questions.
Where are you in the Bay area ? I used to spend time out therein Burlingame. San Mateo area, many years ago.
Ralph
OLDSter Ralph is offline  
Old December 30th, 2017, 12:17 PM
  #14  
Registered User
Thread Starter
 
Join Date: Feb 2013
Location: San Francisco area in formerly wonderful California
Posts: 49
J-2 carb setting

Hi Ralph----

I'll add another photo of the valley showing the roller lifters and the bronze sleeves necessary as the Olds lifters are larger. We used smaller Chevie rollers and hence the sleeves.

John Rankin at Rankin Machine in Martinez CA did the work. He specializes in the older engines.

Mondello is here in Paso Robles CA. http://www.mondellotwister.com/

Joe Mondello was the original Olds expert but he died several years ago. Son Lynn took it over and specializes in the newer Olds engines but still has or can get the stuff for the early motors. I discovered Ross after I was already working with Mondello.

I have the bumpy rocker covers and adjustable rockers I got several years ago from Dr. Oldmobile note spelling-----his web site: http://www.droldmobile.com/index.html

He still shows them as available and he is a former Olds engineer.

The original 303 series Olds engines were designed by Kettering who also designed the small block Chevie motor hence the similarity of the motors.

I'm not certain of the rocker ratio but think it is 1.5.

Attached are a few photos---I hope they come through---plus a bonus shot of the headers and the Ford suspension.

A few articles you may find interesting:

http://www.hotrod.com/articles/0901s...le-v8-engines/

https://1957oldsmobile.jimdo.com/old...ngine-history/

I am in Walnut Creek----in the east Bay.

Good luck with your project and let me know if you have any other questions.

Bill---
Attached Images
File Type: jpg
IMG_3355[1].jpg (1.86 MB, 24 views)
File Type: jpg
20160805_121732[1].jpg (4.54 MB, 28 views)
File Type: jpg
20160805_120339[1].jpg (4.30 MB, 19 views)
File Type: jpg
IMG_3603[1].jpg (2.11 MB, 22 views)
File Type: jpg
20130526_141420[1].jpg (3.43 MB, 20 views)
File Type: jpg
20130517_164312_(1)[2].jpg (2.99 MB, 24 views)
bspaulding is offline  
Old December 30th, 2017, 04:41 PM
  #15  
Registered User
 
OLDSter Ralph's Avatar
 
Join Date: Sep 2017
Location: St. Paul Minnesota
Posts: 1,140
Bill,
.......more later tonight when I have time.
Ralph
OLDSter Ralph is offline  
Old December 30th, 2017, 06:30 PM
  #16  
Phantom Phixer
 
Charlie Jones's Avatar
 
Join Date: Dec 2011
Location: Apopka, FL
Posts: 2,268
Camshaft Failures

I have noticed quite a few threads mentioning flat tappet camshaft failures in these "early" Olds V-8s .
There is a small detail in engine assembly , which may be causing some of these failures .
And that is the orientation of the connecting rods during assembly . There is a small hole drilled in one side of the rod cap , near the parting line . When this hole aligns with the crankshaft journal oil hole the oil pressure "spurts" oil out through the hole toward the camshaft .
These holes must be installed "up" toward the camshaft . If any of the rods are not installed properly , the camshaft will not get the proper oil .
The service manual probably has a better explanation . And is a good read for anyone assembling these engines .
Charlie Jones is offline  
Old December 31st, 2017, 08:47 AM
  #17  
Registered User
 
OLDSter Ralph's Avatar
 
Join Date: Sep 2017
Location: St. Paul Minnesota
Posts: 1,140
Originally Posted by Charlie Jones View Post
I have noticed quite a few threads mentioning flat tappet camshaft failures in these "early" Olds V-8s .
There is a small detail in engine assembly , which may be causing some of these failures .
And that is the orientation of the connecting rods during assembly . There is a small hole drilled in one side of the rod cap , near the parting line . When this hole aligns with the crankshaft journal oil hole the oil pressure "spurts" oil out through the hole toward the camshaft .
These holes must be installed "up" toward the camshaft . If any of the rods are not installed properly , the camshaft will not get the proper oil .
The service manual probably has a better explanation . And is a good read for anyone assembling these engines .

Charlie, thank you, a point I will now be aware of when I start on the '57 engine.
I have read some threads that discussed "lubricants", "defective" cam grinder cores, "defective" lifters and restrictors. I haven't drawn a clear conclusion as to flat tappet vs. roller cam.
Ralph
OLDSter Ralph is offline  
Old December 31st, 2017, 09:22 AM
  #18  
Phantom Phixer
 
Charlie Jones's Avatar
 
Join Date: Dec 2011
Location: Apopka, FL
Posts: 2,268
Originally Posted by OLDSter Ralph View Post
I have read some threads that discussed "lubricants", "defective" cam grinder cores, "defective" lifters and restrictors. I haven't drawn a clear conclusion as to flat tappet vs. roller cam.
Ralph
Any of the factors you mentioned COULD cause a ruined camshaft .
The orientation of the connecting rods , however , is often overlooked . Even by the "experts". It WILL cause camshaft failure .

In my opinion , installation of a roller cam is totally unnecessary . Provided that everything is properly assembled . and quality components are used .

Last edited by Charlie Jones; December 31st, 2017 at 09:32 AM.
Charlie Jones is offline  
Old December 31st, 2017, 09:23 AM
  #19  
Registered User
 
OLDSter Ralph's Avatar
 
Join Date: Sep 2017
Location: St. Paul Minnesota
Posts: 1,140
Originally Posted by bspaulding View Post
Hi Ralph----
I'll add another photo of the valley showing the roller lifters and the bronze sleeves necessary as the Olds lifters are larger. We used smaller Chevie rollers and hence the sleeves.

John Rankin at Rankin Machine in Martinez CA did the work. He specializes in the older engines.

Mondello is here in Paso Robles CA. http://www.mondellotwister.com/

Joe Mondello was the original Olds expert but he died several years ago. Son Lynn took it over and specializes in the newer Olds engines but still has or can get the stuff for the early motors. I discovered Ross after I was already working with Mondello.

I have the bumpy rocker covers and adjustable rockers I got several years ago from Dr. Oldmobile note spelling-----his web site: http://www.droldmobile.com/index.html

He still shows them as available and he is a former Olds engineer.

The original 303 series Olds engines were designed by Kettering who also designed the small block Chevie motor hence the similarity of the motors.

I'm not certain of the rocker ratio but think it is 1.5.

Attached are a few photos---I hope they come through---plus a bonus shot of the headers and the Ford suspension.

A few articles you may find interesting:

http://www.hotrod.com/articles/0901s...le-v8-engines/

https://1957oldsmobile.jimdo.com/old...ngine-history/

I am in Walnut Creek----in the east Bay.

Good luck with your project and let me know if you have any other questions.

Bill---

Hi Bill,
1. Did he use an AL-Ni-Bronze like AMS4640 or AMPCO for the sleeves ? I'll have to find someone here locally that knows about older Olds engines or another solution.


2. Mondello in Paso Robles has been surrounded by some controversy from threads I have read. Lynn is in Paso Robles, I think, and Bernie IS the son of Joe Mondello and is in Tennesee.
Right now, I am leaning toward Ross Racing Engines for pistons. Camshaft, I am wavering between hydraulic and roller lifters.


3. I am going to contact DrOldmobile on Monday about the bumpy valve covers and adjustable rockers. I wasn't aware that any were still around for purchase, thanks.


4. Great looking headers !!!! I assume they are custom made. Are they Stainless steel ?


5. What tranny, rear end and rear gears are you using ?


6. Trust me, I am printing out the thread and saving it in a "paper" file folder. I'll read and print out the articles you sent links to.


Thanks a bunch for all the info.
Ralph
OLDSter Ralph is offline  
Old January 4th, 2018, 06:59 PM
  #20  
Registered User
Thread Starter
 
Join Date: Feb 2013
Location: San Francisco area in formerly wonderful California
Posts: 49
J2 Carb Jetting

Hey Ralph---


Your questions:

1) He used Ni Bronze sleeves and he got them from a supplier in Newark CA. I misplaced the name but can get it again if you need it.

2) I too would go with Ross but as I said I learned of them after I had been working with CA Mondello.

3) What did you find from Droldmobile? Does he still have the stuff?

4) Headers are custom made by Sanderson as is the entire exhaust system in Stainless. He ran the two pipes on the passenger side of the car and exited the left bank on the passenger side and the right bank on the drivers side in an attempt to make the pipes equal length. There was just not enough room on the drivers side for the exhaust with the power brakes and hydraulic clutch. The headers also had to snake around the 2004 FORD Crown Vic Police front end assembly.

5) The trans is a tremec 5 speed TKO500/600. The rear end is from a '99 Ford Explorer 8.8 which gave us disc brakes on all corners. The gear ratio is abut 3.7?. I tach 2100 at 70 mph. running the biggest tires I could fit in the wheel wells. The rear axle was welded into the original Olds rear suspension so the car retains the classic lift on acceleration.

6) Anticipating your next question here are shots of the Ford Vic crossmember we narrowered about 3" to fit. (using a certified aluminum welder) Also, note how the frame was modified. We got the idea from Arron on Fast 'n Loud TV. For $200 at Pick n Pull, we got the disc brakes, sealed spindles, strut suspension and power rack all of which was rebuilt.

Still suggest a roller cam and suggest you contact Elgin. We dyno the car tomorrow...If good news, I'll post, otherwise there just might be a Olds for sale...
Attached Images
File Type: jpg
2013-03-27_10.52.07[1].jpg (1.46 MB, 9 views)
File Type: jpg
20130223_095152[1].jpg (2.30 MB, 9 views)
File Type: jpg
20130327_152910[1].jpg (3.60 MB, 11 views)
bspaulding is offline  
Old January 11th, 2018, 10:28 PM
  #21  
Registered User
 
OLDSter Ralph's Avatar
 
Join Date: Sep 2017
Location: St. Paul Minnesota
Posts: 1,140
Hi Bill,
1. How did you do on the dyno ?
2. What jetting did you end up with after the dyno run ?
3. It sounds like he used Al-Ni-Bronze (AMS4640 or Ampco 21)for the lifter bore bushings. That's some difficult to machine material, but would never wear out.
4. I keep forgetting to call DrOldmobile during the day. I put it on my "list" for tomorrow.
5. Headers might be something later. Ross might have header flanges or know where I could get them.
6. I talked to Ross about a roller cam, and he can do the machining needed. I am leaning toward a roller cam. I am also looking for another engine to modify. Flat tappet/camshaft failures concerns me.
Ralph
OLDSter Ralph is offline  
Old January 12th, 2018, 11:22 AM
  #22  
Registered User
Thread Starter
 
Join Date: Feb 2013
Location: San Francisco area in formerly wonderful California
Posts: 49
J-2 carb setting

Hi Ralph---

Well the dyno run was disapointing----we did not pick up any more power but we did have linkage issues where the end carbs would not open---by the time we gt that sorted out, the day was gone but she is going back on the dyno next week.

Re your other comments:

Headers. I got my stainless header plate and stubs from Tanson Enterprises in Sacramento CA. Remember the pax side has the bracket for the generator cast into the exhaust manifold. Harry at Tanson modified his pattern to include the bracket on the flange he cut for me plus a doubler. (916) 752-8790. When you google the company you get a Yelp page with a green Olds motor. That is exactly how I mounted my accessories. I had to modify the new alternator bracket on the drivers side to clear the front carb.
My stainless welding is not the greatest. I chamfored the perimeter and did several plug welds to make it one solid piece.
I also got my electric windshield wiper set up from him. Who knows what other goodies he may have. No website I can find and no catalog----guess ya just have ta ask.
Attached Images
File Type: jpg
20130517_164224[1].jpg (3.14 MB, 8 views)
File Type: jpg
20130517_164245[1].jpg (3.05 MB, 9 views)
File Type: jpg
20130403_090133[1].jpg (3.12 MB, 10 views)
bspaulding is offline  
Old January 12th, 2018, 11:41 AM
  #23  
Registered User
Thread Starter
 
Join Date: Feb 2013
Location: San Francisco area in formerly wonderful California
Posts: 49
More notes:

Found the link to Tanson---http://www.forwhatyouneed.com/index.htm

Also another helpful link: https://www.jalopyjournal.com/forum/...mpiled.715390/
bspaulding is offline  
Old April 8th, 2018, 10:31 PM
  #24  
Registered User
 
OLDSter Ralph's Avatar
 
Join Date: Sep 2017
Location: St. Paul Minnesota
Posts: 1,140
Hey Bill,
What has happened in the last few months ? Did you get your engine on the dyno again ? I was away with work and other maladies.
I am looking for a 2nd 371 to "warm up". I have decided to rebuild the original engine to stock specs and build a 2nd engine for "playing".
I got a pair of the dimpled valve covers but haven't had time to look at them yet.........still in the box.
I'll be dragging the '57 out of the woods and changing to tires that hold air as soon as the last foot of snow melts. I am hoping to start looking over my '57 in a month or so.
Ralph
OLDSter Ralph is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
1BOSS83
Small Blocks
40
October 11th, 2015 07:58 AM
brown7373
Cutlass
19
October 22nd, 2014 07:35 PM
Nufo
Big Blocks
1
August 8th, 2013 10:16 PM
tinner
Small Blocks
3
August 24th, 2012 01:27 PM
67Olds442X2
Big Blocks
16
February 11th, 2012 01:05 PM


Thread Tools
Search this Thread
Quick Reply: 1957 J2 center carb jetting


Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.