Your donations help keep this valuable resource free and growing. Thank you.
|
Timing Chain Questions ? |
Post Reply | Page <123> |
Author | |
TinMan
AMC Addicted Joined: Mar/23/2008 Location: CO Status: Offline Points: 1659 |
Post Options
Thanks(0)
|
Heh.
Well, depending on how far back you go, 3+ valve engines weren't very common in the US. Look at the majority of the older American i6's, and then look at the older Nissan and Toyota i6's. Same with overhead cams and dual overhead cams. Ever see a 5 valve Audi/VW engine? When you compare them to their 4 valve engines, it's like they just engineered another one in there just for kicks or something, looks really out of place and they make about the same power as the 4 valve equivalents. |
|
poormansMACHINE
AMC Addicted Charter Member Joined: Jun/28/2007 Location: Shoemaker-Levy9 Status: Offline Points: 12302 |
Post Options
Thanks(0)
|
Each had different goals for their engines. For the US market, the 6 was the bottom of the line allowing you to go from point A to B.
In overseas markets, the 6 was a step up as was our 8. |
|
farna
Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19686 |
Post Options
Thanks(0)
|
Got me! I doubled valve instead of cylinder count, obviously.
|
|
Frank Swygert
|
|
billd
Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
Post Options
Thanks(0)
|
in any case, the two very low compressions are a concern........ if adjacent, like said, head gasket blown is possible, or it's possible it's a coincidence they are next to each other.
In any case, any time you have more than a 10% difference, you have an abnormal compression pattern and should be suspect............... You can do a leakdown check. You can pull the valve cover and see what's operating and what's not, and get a close check on the valve timing that way as well, depending on the tools you have and the specs you have available. |
|
258guy
AMC Apprentice Joined: Jan/25/2010 Status: Offline Points: 18 |
Post Options
Thanks(0)
|
Thanks everyone for the input. I did pull cover, everything looks ok ? A 3rd generation AMC dealer service manager told me that he saw a lot of 258's jump time and run like sh-- ! The part that has me thinking is what the previous owner told me, "All of a sudden it just started to run bad" so i parked it. Can it be off just a tooth and cause the low compression ?
|
|
billd
Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
Post Options
Thanks(0)
|
Not on just two cylinders.......... a blown head gasket could be sudden and impact 2 cylinders that are next to each other (because I can't spell adjacent, I used that phrase instead)
|
|
1970390amx
AMC Addicted Joined: Jul/11/2008 Location: colorado Status: Offline Points: 3314 |
Post Options
Thanks(0)
|
as stated before, if the cam timing is off it will affect all cylinders the same. the two that are low need to be addressed. A leakdown test can determine what the cause of low compression. If it has bad rings or valve sealing problems the condition of the timing chain is not important. If you start it and check the timming is it close. if it is the timing chain probaly has not jumped, unless PO has messed with it in an effort to make it run better.
|
|
1970 390 4speed Bittersweet shadow mask AMX
1970 Amx missing most everything, or in a box |
|
258guy
AMC Apprentice Joined: Jan/25/2010 Status: Offline Points: 18 |
Post Options
Thanks(0)
|
Thanks I think I must have a blown head gasket, color of inside rad tells me it got hot at one time.
|
|
poormansMACHINE
AMC Addicted Charter Member Joined: Jun/28/2007 Location: Shoemaker-Levy9 Status: Offline Points: 12302 |
Post Options
Thanks(0)
|
What color are you seeing that says overheat??
|
|
billd
Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
Post Options
Thanks(0)
|
Lots of pretty colors - a virtual rainbow! LOL - white milky could mean trouble. Rusty means it's simply old and hasn't been changed in years and the anti-oxidation chemicals are toast. If it's got a horrible bitter smell out the tail, that's not a good thing, Martha. |
|
Post Reply | Page <123> |
Tweet
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |