judging a C1 SJ4653 Jack

[Ian G.]

I just bought a SJ4653 jack from Corvette Central, since I heard they have one of the best reproductions and an original can cost $700+. I have some pictures below. I understand it has the following prtoblems:

1. the rivets are not rough enough
2. the bearing is too big
*what is the proper inside diam x outside diam. x width?
3. the waffle pattern on the bottom is either:
*should not be there
*too pronounced
4. The transverse ribs on the base should be lower than the parallel ribs
*how much lower in thousands --
I may consider getting it machined and stipled.

Pics of the CC jack attached.

Would someone be kind enough to post nice closeup pics of these things from a known original jack? As well as any other observations? Maybe even pics of other reproductions so we can compare. My main objective is to see if it is possible to reduce the points hit I will take.

[Ian G.]

Re: judging a C1 SJ4653 Jack

A couple additional pics

[Tom P.]

Re: judging a C1 SJ4653 Jack

If I get a chance, and if I don't forget (that's the key word!!!), and if someone doesn't post pictures of an original, I'll take some pictures of the one in the 56 after I get home tonight.

[Henry F.]

Re: judging a C1 SJ4653 Jack

Ian: In pic #2 your rivet looks too perfect, your waffle's look OK.
In your 2nd post my bearing is about 1-3/8 dia. with the following stamping,"IRWIN BEARING CO. CINTI O. (facing inboard) & "MADE IN USA TOP H19B" (facing outboard)
Your bearing appears to be installed backwards.
This info is from my 57 original jack.
I hope this helps.

[Tom P.]

Re: judging a C1 SJ4653 Jack

This is the jack from my 56.
The OD of the bearing is 1 3/8in.

[Ian G.]

Re: judging a C1 SJ4653 Jack

Awesome pics. You rock, Tom
Could you check what the width of the bearing is?
Is your bearing stamped with the same verbiage as Henry's?

[Tom P.]

Re: judging a C1 SJ4653 Jack

There is nothing at all stamped on the bearing (that I can see).

[Gary C.]

Re: judging a C1 SJ4653 Jack

Ian, look closely at Tom's next to last photo that shows the saddle and the SJ4653. The base's middle reinforcing ribs are recessed (have a step down). Didn't see that on your reproduction photos. Gary....

[Tom P.]

Re: judging a C1 SJ4653 Jack

It is my understanding that 53-61 jacks are all the same, correct?

[Stewart A.]

Re: judging a C1 SJ4653 Jack

Ian the jacks are qiet different. The judges will pick a repo a mile away. I think it's a matter of taking a hit for the incorrect jack.
An original is way more than 700 try in the thousands. What I don't understand companies go to all this effort to re produce a part, why don't they just do it correct in the first place !! They chuck some numbers on a part and bluff everyone into thinking it's spot on.
Stewy

[Bob B.]

Re: judging a C1 SJ4653 Jack

Hi all,

I have an original jack and it has the Irwin Bearing Co. bearing, etc. One of the differences judges look at is the area around the SJ4653. On the original, the SJ4653 sits in a depression and there is a trapezoid of bars around it. There is a distinct step up from the horizontal bars below and above the SJ4653 where they hit the vertical bars (see Henry's pictures). Also the rivet stamping is different on some.

I'm glad I have an original jack. And I agree with Stewy in wondering why the makers of repro items can't seem to go all the way and make them totally correct. That being said, however, the repro jack is pretty good and, if I had one, it is close enough that I would put it in my trunk and never think about it again.

Bob

[Roy B.]

Re: judging a C1 SJ4653 Jack

Ian the jacks are qiet different. The judges will pick a repo a mile away. I think it's a matter of taking a hit for the incorrect jack.
An original is way more than 700 try in the thousands. What I don't understand companies go to all this effort to re produce a part, why don't they just do it correct in the first place !! They chuck some numbers on a part and bluff everyone into thinking it's spot on.
Stewy

It's like the interior material (seats and door panels) soft tops and so on, how many times over the years have we head (improved or now NCRS correct) . I wonder how many times people have had to replaced repro parts when the JM got more detailed in it's inscription .

[Ian G.]

Re: judging a C1 SJ4653 Jack

hey Gary, Thanks for pointing that out, but in my original post I mention that. It's good to have a pic though:

4. The transverse ribs on the base should be lower than the parallel ribs
*how much lower in thousands --
I may consider getting it machined and stipled.

hey Stewy,

I actually bought an original (just didn't have a macro lense camera at the time) for only $700. I sent it back, becasue bubba had welded nuts to the nose and ground off material all the way around it. I've seen them go on ebay for $700-1000. But that's a lot of money for mayube what 2 points lost?

Anybody else with an original jack, lets get some pics up for everyone's reference. Also, if someone has a Dr. Rebuild Jack or one from Paragon, lets get pics of it up for comparison. I think it would be helpful to everyone. Lets take advantage of this board!

[Gary C.]

Re: judging a C1 SJ4653 Jack

Ian, the middle ribs are somewhere between 1/32 and 1/24 of an inch lower.
Tom, as far as I know all 53-61 jacks are the same. 62 changed slightly.
Y'al made me look at the bearing on my original '57 jack. Could make out on the bearing outer ring "Made in USA" side which faces the jack. There was other stamping, but didn't want to remove the paint. Best, Gary....

[Bill M.]

Re: judging a C1 SJ4653 Jack

Here are pics of the original, unrestored jack from a '59 assembled in Dec. '58. This jack got used a lot. It is painted red. The bearing measures 1.425 by 0.457. The lower ribs I measure at 0.020 down.