TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > AMC 6 Cylinder Engine Repair and Modifications
  New Posts New Posts RSS Feed - Timing Cover
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

Timing Cover

 Post Reply Post Reply Page  12>
Author
Message
tloftus View Drop Down
AMC Nut
AMC Nut
Avatar

Joined: Mar/18/2008
Location: Sioux City, IA
Status: Offline
Points: 272
Post Options Post Options   Thanks (0) Thanks(0)   Quote tloftus Quote  Post ReplyReply Direct Link To This Post Topic: Timing Cover
    Posted: Nov/17/2019 at 8:09pm
In the middle of rebuilding my '78 258.  Put the timing gears on tonight and the timing cover will not go on.  The cam sprocket bolt is sticking out too far for the cover to seat all the way down.

Closer inspection of the cam sprocket against the old one and it appears that while the teeth and overall thickness of the sprocket is the same the new gear isn't as "deep" on the inside allowing the washer and bolt to seat in far enough for the cover to go on.  I put the old gear on and the cover goes on fine.

I've found the old style gear on eBay, and can probably just order one.  However it has the nylon teeth and would rather use the new gear which is all metal.

Any thoughts?




Tom




Edited by tloftus - Nov/17/2019 at 8:11pm
1966 AMC Rambler American Rogue - 232 I6
http://theamcforum.com/forum/1966-amc-american-rogue_topic20995.html

1978 AMC AMX - 258 I6
http://theamcforum.com/forum/1978-amc-amx_topic62333.html
Back to Top
FSJunkie View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/09/2011
Location: Flagstaff, AZ
Status: Offline
Points: 3578
Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2019 at 2:38am
The nylon cam gear looks stupid but in actual practice they last well past 100,000 miles. I've seen them still going with close to 200,000 on them.

I did not run into this problem when I installed a new steel cam gear in my 1977 and 1984 sixes. Their cam bolt cleared the timing cover no problem. Perhaps you got a low quality cam gear.
'66 Marlin: 327/T10/3.54 Twin Grip
'72 Wagoneer: 360/TH400/3.31
'73 Ambassador: 360/TF727/3.15
'77 Hornet: 232/TF904/2.73
'84 Eagle: 258/TF998/2.35
Back to Top
farna View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar
Moderator Lost Dealership Project

Joined: Jul/08/2007
Location: South Carolina
Status: Offline
Points: 16553
Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2019 at 6:07am
How much difference is there? If it just needs a little clearance you could carefully grind the hub of the gear down a little in back. It doesn't have to be perfectly flat there, but if concerned about that could take it to a machine shop to be surfaced. Take the old gear and match the measurement. It can't be off much or there would be an issue with the crank gear also. Should be no more than 1/16" off (0.0625"). 0.040-0.060" off shouldn't make a difference in the chain, you'll have to measure the two hubs and see if that's enough. The bolt and cam shouldn't expand more than 0.010-0.020", so 0.030" or so clearance should be adequate.
Frank Swygert
Back to Top
tloftus View Drop Down
AMC Nut
AMC Nut
Avatar

Joined: Mar/18/2008
Location: Sioux City, IA
Status: Offline
Points: 272
Post Options Post Options   Thanks (0) Thanks(0)   Quote tloftus Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2019 at 8:03am
When I install the new cam gear it is very close to the block.  It may even be touching but when I compare the two the rear recesses appear to be the same.

On the old one the front is "dished" out more than the new one, allowing the washer and bolt to sit in further and allow the timing cover to clear.

When I put the new one on and torque down the bolt, the timing cover actually rocks on the bolt, I would say there is a good 1/16" gap between the cover and the block.  I could grind off the back but if the cam is bottomed out in the recess (I think it is) then grinding off the back might work by allowing the cam to go further into the block.

Headed back to the parts store to see if they have another one, maybe this one is defective.  If that doesn't work I'll probably just buy the nylon one. 
1966 AMC Rambler American Rogue - 232 I6
http://theamcforum.com/forum/1966-amc-american-rogue_topic20995.html

1978 AMC AMX - 258 I6
http://theamcforum.com/forum/1978-amc-amx_topic62333.html
Back to Top
Heavy 488 View Drop Down
AMC Nut
AMC Nut


Joined: Apr/27/2019
Location: Wasco
Status: Online
Points: 444
Post Options Post Options   Thanks (0) Thanks(0)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2019 at 8:30am
Replace it. China strikes again?
Start cobbling on the back side all you need is gear wobble.

Back to Top
tloftus View Drop Down
AMC Nut
AMC Nut
Avatar

Joined: Mar/18/2008
Location: Sioux City, IA
Status: Offline
Points: 272
Post Options Post Options   Thanks (0) Thanks(0)   Quote tloftus Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2019 at 8:44am
I went back to the parts store -- the gear they had in back was (as expected) exactly the same.  I guess it's possible there is a bad batch or something but there's no way anyone got this to work without either a thinner washer or modifying the gear itself.  I just don't see how it could ever work.

I've ordered the nylon gear and will use it.  Guess it will be an unsolved mystery.  Smile

Thanks,
Tom
1966 AMC Rambler American Rogue - 232 I6
http://theamcforum.com/forum/1966-amc-american-rogue_topic20995.html

1978 AMC AMX - 258 I6
http://theamcforum.com/forum/1978-amc-amx_topic62333.html
Back to Top
Heavy 488 View Drop Down
AMC Nut
AMC Nut


Joined: Apr/27/2019
Location: Wasco
Status: Online
Points: 444
Post Options Post Options   Thanks (0) Thanks(0)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2019 at 9:07am
You could also look into a stock replacement for a Jeep 4.0. it's a single roller.
Back to Top
Trader View Drop Down
AMC Addicted
AMC Addicted


Joined: May/15/2018
Location: North America
Status: Offline
Points: 1534
Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2019 at 12:18pm
The S388 is the same casting number for Enginetech, Melling and Cloyes (C3035).
The Seal Power KT3493S gear has the recess for the washer.
Back to Top
tomj View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/27/2010
Location: los angeles
Status: Offline
Points: 3618
Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2019 at 8:06pm
i just changed the timing set in my 199 a couple weeks ago. the original plastic gear, 198,000 miles. noticable wear on the teeth, chain slack, still quite a ways from failure.

i have nothing else to offer here, other than i got a Mahle kit, i think it was, with the repair sleeve.  all steel sprocket, no clearance issues. the rear is of course recessed with the locating pin.

what *exactly* is hitting? dab some paint on various places and check.


1961 roadster american, 195.6 OHV, T5
1968 american, 199ci, T96
sr-ix.com

Back to Top
farna View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar
Moderator Lost Dealership Project

Joined: Jul/08/2007
Location: South Carolina
Status: Offline
Points: 16553
Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Nov/19/2019 at 6:27am
My best guess is that you probably are getting a 4.0L timing gear. Someone collapsed a catalog and spec'd the newer part as fitting all. This happens a lot, and often small things like that dish are missed. A newer timing cover might solve the issue, but I'd just get the nylon covered gear or a different manufacturer that fits correctly, such as the Sealed Power gear Trader mentioned. The newer timing covers have larger bolt holes in some places due to a difference in how accessories were mounted (I believe 74 and newer). There are enough bolts the same size as the older ones that it will align correctly on those, washers on the larger holes. Bolt pattern is the same.
Frank Swygert
Back to Top
 Post Reply Post Reply Page  12>
  Share Topic   

Forum Jump Forum Permissions View Drop Down



This page was generated in 0.094 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or