CJ-3A with Chain Drive Engine.

[wylde]

OK, So I am restoring a CJ3A.

I crack the Engine open and wha-la there is a Chain on my Engine.

It looks like a CJ Engine block, from what I know of a CJ and MB Engine.

Next Question, Im getting ready to O.H the engine with all new parts, Now that I have a Chain should I get the Chain drive Kit or go back to the Gear-Gear Kit.

and last related Question is the Chain Cam, the same cam as the Gear drive cam?

[p3ferris]

Keep it chain cam it is cheaper than to change it.

[artificer]

If staying with chain I would recommend & Ron has the Saunders roller chain conversion which is much quieter in service & will last indefinitely.

[Sean Collins]

Now that I have a Chain should I get the Chain drive Kit or go back to the Gear-Gear Kit.

Converting from one type to the other requires that ALL of these parts be changed:

Cam, gear set or chain & sprocket set, oil pump gear (or entire pump), timing cover.

On top of all that (which is expensive by itself), if the engine is factory chain drive, it would require additional machining on the block to accomodate a gear set, which would be a significant added expense.

While it's easy to retrofit a chain system in a gear drive block, the opposite is not. Unless you have a specific need, it's not worth the time, cost & effort to do either.

last related Question is the Chain Cam, the same cam as the Gear drive cam?

No, see above.

Sean

[wylde]

Well I think I am at more a loss, and twice as confused.

Was hoping for a direct YES or No, on this.

Any one know where there is a IPC or OH-MM On line for this Engine?

[p3ferris]

No I would not
No it is not the same. There you have it
We sould be lieing if we said it could not be done. Expensive.

[snowdad]

Are you sure it is a cj3a engine and not a MB/GPW replacement? What about numbers on the block/head?

[Ben Dover]

And your Jeep will not notice the difference, the change back and forth from late to early engines have been taking place since CJ first came on the market.

[wylde]

The Block has the standard Cj / NON WWII Head, now that is not to say that what I have is not a WWII Block.

Here take a look at the pics, I am sure I can get more pics if some one wants close up pics of items.

[sjalbert]

It is a post war block. What (if anything) is stamped on the top of the water pump boss?

[Sean Collins]

The Block has the standard Cj / NON WWII Head, now that is not to say that what I have is not a WWII Block.

Post-war, after Nov. 1950. Would have been gear drive originally.

[wylde]

So.... There should not be a Chain on that block, I agree.

What do I do?

Should I, go back to the direct Gear Drive?

or stay with chain?

I am looking to order a kit a complete OH kit that includes every thing Including new Gears or New Chain, as well as new Oil Pumps.

[Cuz]

Can you post these three numbers?

l.jpg (54.85 KiB) Viewed 602 times

Complete overhaul kits are great when you have the option to tailor them to exactly which parts and which dimensions (oversize/undersize) you need. The cam, crank sprocket/gear, timing chain/gear cover will not be included so to switch from one system to the other you will have to purchase these items in addition to your complete overhaul kit.

If you are not restoring a factory class jeep on which you want all the correct parts then I would suggest keeping the engine configured the way it is and rebuild it accordingly. It will cost considerably less. I would invest in the Aussie chain and sprocket set mentioned above. You can purchase it through Ron F's parts store.

[wylde]

yea, will get that info tonight, Engine is about 40 miles away, at one of my unit members house.

I will get him to send me that info.

[wylde]

head number =
W5
6-48
800376
3-10

Block Water Pump Boss =
3J.105068

Block Side Number =
641087-W-12-D-P5 CU CR