Ram started ticking and turned into a knock. I had some overheating issues recently and basically replaced the cooling system. After the new water pump and thermostat, it was overheating only when going up a long steep hill. A new radiator fixed this problem. However, the knock was getting worse. The knock briefly turned into a rattle and then turned into more of a sputter.

We did a compression test last night and cylinder 1 is completely gone. A big 0 and we triple checked. All others were 150. The ground electrode on that spark plug (recently changed them all so it was new) was completely broken off! Another thing is there is oil coming out of the throttle body.

My brother (mechanic) thinks it could be a bent/burned valve but is wondering if there could be a hole in the piston since we saw the oil in t
T body. We won't know for sure until we take it apart but I wanted to see if you all had any ideas? Since it had overheating issues I guess it could be cracked head?

If it is just a valve, I think we'll just replace it and re-gasket everything, etc. Any worse and I'm thinking I might as well put a new engine in it? Labor is free but an engine swap might be easier. Current engine has 104k so I'd really like to salvage it.

If it does makes sense for a new engine, any recommendations on aftermarket engines? I'd love to go with a used hemi but from what I've found on here, it looks to be a pain with the wiring.

Any input is appreciated. Thanks
2002 (although most parts happen to be 2003) 1500 4.7 Automatic

 

4.7s DO NOT handle over-heating well at all. There is a very real possibility of a cracked head. Just dig into it and find out.

As far as a replacement engine, 4.7s aren't terribly high and yeah, a Hemi upgrade ain't easy...

 

If it was a 5.7 I'd bet you broke a piston, not sure if the 4.7's have the same problem.

 

4.7s do have a common issue of throw rocker arms which in turn would not push the valve down and get the same zero compression reading. Other than that I would check the valve spring and then pull the head

 

You need to do a leakdown test and find out where the air is going. It can go out the T/B, out the exhaust, or out the oil cap. Re-do it and then come back in. Doing a compression test is only half the solution and whatever you do STOP running/driving it. If the plug is broken, my guess is that you have lost some skirting on the pistion and it got caught up in your exhaust valve on it's way out and bent the valve thus causing you to have a zero reading.
Also, a compression test requires you to tuen the endinge over with the key, this is bad news if theres something broken inside there. A leakdown test you can turn the engine over by hand to get that piston at TDC so both valve are closed. Then you pump the air into the cylinder and listen to where it's escaping.

 

Thanks for the info, guys. We're taking it out on saturday to take a look. I'm really thinking about just putting a used low-mileage engine in. I'm going to have some money into re-gasketing everything, etc anyway.

I'll let you all know how it goes.

 

I really don't know the feasibility of this, but I have seen complete Hemi engines, from exhaust, to wiring, to PCM, on ebay for around $2500 - $3500. Like you said, people say its hard and I trust them, but since you asked I thought I'd share.

 

the rocker studs that bolt to the head crack on 4.7's i have seen 4 of them so far.
take off your valve cover and check for cracks that would also give you a rattling sputter sound.
if its not that your looking at a valve or cracked head

 

Looks like I have a piston in REALLY bad shape and in turn that banged up the head. Probably broke a rod. The piston was loose and I could actually move it around a little. Otherwise the head was ok and rockers/rocker studs are good. At this point, I think I've seen enough but I might take off the oil pan to see what is looks like underneath.

I'm not going to try to rebuild this one. Trying to find a used engine to just drop in. After reading a little on DT, they gave me a little hope for a hemi. I think if I can get the whole engine, computer, and wiring harness I might be ok. Might get a new thread going.

Here are some pics of the bad piston and head
http://img717.imageshack.us/slidesho...=img0332ah.jpg

Thanks for all the help

 

Humm, sorry to hear that, but good luck with the new project. I guess the 4.7 and 5.7 do have that problem in common.