My 03 Ram 1500 crapped out on my daughter a few months ago and I finally got to*tear into it. I thought it had jumped time because I cøuldn't get it to start and it was backfiring when cranking. after removing the valve covers, I saw 3 rockers had jumped off of the valves and were laying on the head.

after rotating the cam to the flat side I could slip the rockers into place with about 1/8 inch clearance and could easily knock them back off. tried cranking a few times and no change, I hear there could be either carbon stuck in the valve, or guides stuck or seats that dropped... I am clueless as to how to fix this and in no hurry to pull the heads... any suggestions? I hear this is a fairly common thing on the 4.7's

 

Yep, fairly common to see 4.7s throwing rockers but since the 3.7 isnt much difference I can see where it could happen there also. I havent seen anyone with the issue on a 3.7 but we have so few 3.7 members here (unless they are scared of all us 5.7 guys and dont speak up ).

Anyway, sounds like to do you are going to have to pull those heads and see if it is the valves that are limited to their return position or if there are flat spots on the cams.

 

don't forget a lash adjuster (lifter) could have lost its spring or be gummed up with sludge. with these being the other end that holds the rocker arm in place it could also cause the problem. also make sure you check for a crack valve spring.

was this truck overheated in its life? if so it is most likely sunken valve seats. mike

 

I spoke to a 29 year Dodge mechanic that said that a buildup of carbon could cause chunks to get jammed in the exhaust port and keep the valve from closing fully. He said to attach a drill to the valve and see if it will wear down the carbon. I'm going to try on Monday and I'll post the results. For the record, there is some sludge on top of the head, but it's not hardened like I've seen in some cases. more like paste. I'ts not been rebuilt and it has about 140k on the clock.

 

You can verify that with a compression or leakdown test. I've not seen that on a 3.7 to date, but it's possible in any IC engine. The downer is that if the exhaust valve is hanging, it likely got burned, and simply dry lapping it won't fix the problem. The 3.5's had this issue due to overly tight valve stem locks, and often require valve replacement as a result

Is it throwing misfire codes, or just ticking? Because even a small compression leak will cause a misfire.