Camshaft, Timing Cover 258 I6

[EtownCJ5]

ANyone have any experience with a camshaft moving forward with enough force to crack the timing cover? What could cause this? Is there a spring that belongs between the sprocket and cover? I do not see any on the parts diagrams.

Any help would be appreciated.

[cscotted]

cam walking out?? loose chain to sprocket tension?? maybe??

[ctm]

at some point there was a change to the cam bolt and it got a center hole to hold a little spring and a spring cover to push lightly against the timing cover...my 90 is set up this way

see "camshaft thrust control" on this page

http://www.rebuiltautoengines.com/jeep-articles.html

Camshaft Thrust Control On Chrysler 2.5, 4.0 & 4.2L (Jeep) Engines

AERA membership has reported a mysterious knocking noise on Chrysler 2.5, 4.0 and 4.2L engines used in various Jeep utility vehicles. The noise is loudest at the lower front area of the engine and has, on occasion, been reported in all of the above listed engines. The noise will disappear if the engine is operated at higher than idle speed.

Disassembly of the engine revealed that the camshaft gear was making contact with the timing cover. Recalling the engine's assembly, several machinists remembered encountering a bolt that had an 1/8 hole in it. Most were unsure where to install the bolt.

As of the 1991 production year, Chrysler has updated the engine to a new method of retaining the camshaft in the block. Prior model year engines were equipped with a camshaft thrust plate. This has been superseded by a special bolt, spring, plunger and front cover (see illustration). The plunger assembly maintains constant pressure on the camshaft, preventing it from moving
forward. Camshaft chucking will result if this thrust control assembly is not reinstalled. The pin rests against a small protruding pad in the front cover that is reported to be 1.000 from the gasket mounting surface.

A replacement Pin Package is available from Chrysler under the Part #83502890.

[EtownCJ5]

Thanks guys. Anyone have a picture of this setup or the parts?

[CJ Chet]

Keep in mind that there are also two different timing covers. A thin one and a thicker one. My '86 had a thick one, but the replacement engine I put in ('84 block) has the thin one. Just FYI.

[EtownCJ5]

The cover we put back on was from the old engine and was the thin one. I ordered a replacement through a dealership after noone online seemed to have the part in stock and was 2 weeks out. Dealer quoted 4 days. Search of the local junkyards also truned up nothing.

After talking to the folks at S&S (who I bought the engine from) the camshaft timing set up they sent me required the camshaft thrust spring (not included)
After finding out the parts numbers I found them online:

Thank you for placing an order with moparpartsamerica.com

Items Ordered:
Item: SPRING CAMSHAFT THRU
Price: $1.13
Tax: $0.00
Qty: 1
Total: $1.13

Item: PIN CAMSHAFT BOLT T
Price: $1.38
Tax: $0.00
Qty: 1
Total: $1.38

I didn't order until 5 PM cdt yesterday so no word on whether it comes back out of stock or backordered. Just have to keep my fingers crossed.

Thanks for the help.

[EtownCJ5]

The spring is no longer available from Mopar.

Anybody know where to source this?

Thanks.

[ctm]

did you try ordering by the package number in my previous post
"A replacement Pin Package is available from Chrysler under the Part #83502890"

a google search turns up a few sites:

http://www.hesco.us/shop.asp?action=details&inventoryID=45343&catId=


http://www.amxfiles.com/archive/show.cfm?postid=118452&row=2

[EtownCJ5]

Thanks. They updated my order to that same part number. So now I don't know if I'm getting the spring or not.

Edit: I just went ahead and order the part from HESCO for insurance. Thanks a bunch CTM.