so, I have 7 mopar DOHC heads here. 2 are bolted to engines that have broken a rod, one is bolted to an engine that has filled with rainwater, 1 is completely bare except for cam caps, and two have no cam caps. one of the two with no cam caps is bolted to a 2.4, with supposed pt cruiser lash adjusters. the last is in an engine that supposedly ran when pulled 5 years ago and may or may not have been stored properly.
I also have a coupe of ziplock baggies full of lash adjusters and followers of unknown condition and original application. they all appear to be neon, but I have no way of identifying.
I need to build 2 engines from this pile. one 2.4 for my 98 RT, and one stockish 2.0 for me 97 ACR.
my questions:
1. can cam caps be swapped between heads, or do they need to stay with the correct head? if swapped, is there any way to check and make sure everything is good without a machine shop trip?
2. how do i clean and inspect lash adjusters and followers?
3. any way to figure out what parts came from with the lash adjusters and followers?
4. do these heads survive broken rods usually, or should i expect those heads to be scrap metal like i would on a small block?
5. when assembling and inspecting, what do i look for/pay special attention to?
6. anything other than valve lapping, checking for flatness, and new valve stem seals that i should really do while the head is on the bench? (porting is possible for the ACR, but not the 2.4 at this time)
Cam caps on any OHC engine need to stay in the same position, and same head they were made on. Always line bored in place during production. When you dis-assemble one, make sure you mark them or the factory did. Some do, some do not. No Chrysler specific info here, so I don't know if these heads get damaged with a rod failure. Checking for flatness should include checking along the camshaft bore as well. If you shave it to make a warped one flat the cam is now turning in a warped bore, and easily can cause the shaft to break.
Toss the ones with the missing caps in the recycling bin. Lash adjusters are a bit tough to be sure of, but you shouldn't really be able to compress them. Followers, clean in solvent and toss in a container of oil to relube the rollers. Add the lash adjusters to the same container. I always have the head planed to the correct level of smoothness for the mls head gasket you will be using. The machine shop can vacuum check the valve sealing and flatness at the same time. You should have the valves pulled out and cleaned and lube the guides if they have been sitting for too long.
Coming off an engine with a thrown rod would make me completely strip and clean the head, and I would buy new lash adjusters. Likely it threw the rod after spinning a bearing, so it has sent bits of bearing through all the oil passages. If it left the piston at TDC as it was coming apart, it might bend valves in that cylinder.
In reply to Streetwiseguy :
Thats what i thought about the capless heads. Any sense in keeping the valves, springs and such?
Turner: can a normal machine shop re-align the cam journals?
Are the lash adjusters and followers lobe specific like lifters on a hydraulic pushrod cam?
In reply to Dusterbd13-michael :
A few very high end shops can re-line bore camshafts, but it is rare, which is why you scrap the capless, even if you find the caps. Many shops are now straightening warped heads with an oven and a press to prevent the camshaft problems I noted above. Ferrari shops can frequently do the line bore because even very recent 12 cylinder engines needed it as a service procedure (550 Marenello)
This is the head on the engine that was full of water. I see no rust on the cams and followers, but the valve stems are pretty bad. This is in WAY better shape than i was expecting for how much water drained out.
Vinegar and a brass brush, doing one valve at a time? Then lap them?
Also, are followers lobe specific like lifters on a hydraulic pushrod cam?
Followers tend not to be lobe specific.
In reply to BA5 :
Awesome. In that case I'm a go ahead and do the junkyard 2.7 follower upgrade while I have it apart. What are thoughts on the valves? The rush just appears to be on the this stems at this point in the teardown
If the valves, springs and keepers are good i would keep them. That is an interference motor. If anything happens to the belt you WILL bend the valves, probably all of them, and last time i bought them i believe it was a couple hundred bucks for the full set. Those little tiny keepers are easy to lose during disassembly and reassembly, you might as well have extra. I would take out all the valves, springs, and keepers and put them in a box on the shelf. Better to have and not need as they say. Then remove any steel from the junk heads and take them to a scrap yard as clean aluminum. Those big hunks of aluminum have got to be worth something.
In reply to BA5 :
"Tend not to". I would number everything and keep them on their original lobes as a caution.
