Well last year I did a full rebuild on my 2007 2.3L Duratec engine, I took the head to one the best head shops in town and now with less than 7,000 miles on the rebuild I have a bad valve seal, unbelievable. It's in one cylender and the plug shows oil build up and when I start the truck it blows out a big cloud of smoke. I ordered everything I need to replace the seals while keeping the head on. I will post more as this project moves forward.


Oil clogged plug

 

any warranty on their workmanship?

 

Make sure you keep PCV system working, it creates a negative pressure in the valve cover area so would slow down any valve guide seal leaks, and valve cover or oil pan leaks as well

Intake valve guide seals are, of course, the ones that will allow oil to be sucked down the valve stem because they have the high intake vacuum on the valve side
Could be one has popped up/off, not sure how the seals are mounted/held in place inside the springs

 

I hear you on the PVC and do not think that us the problem because I replaced the pvc valve and the oil separator when I did the rebuild there is less than 7,000 on the motor.

 

No there would be no warranty on a rebuilt head and even if there was I would have to remove the head and bring it back to them and I do not want to have to remove the head.

 

I stuck a camera down into the cylender with the bad valve seal to see how bad it is....you are looking a a new piston with less then 7000 miles. Once I replace the valve seals I going run some seafoam into the intake, gas and oil to try and clean that chamber up. If you have any ideas on how clean it let me know.

 

It took 1 1/2 hr to remove the intake manifold and now I can remove the valve cover. Boy they really suck when designing engines, I remember the good old days when engines were easy to work on.




To this 1 1/2 hr labor.

 

Well I finished replacing all the valve stems and started putting the head together and realized the the head cam journals are damaged, there a number of them that have deep rough groves in them and the cam is the same. I thinking there is no to fix this but for a new head?

 

Yes, that bearing was spinning, i.e. spun bearing

If it was just the one a machine shop can machine it and you can use an oversized bearing

But there would have had to be a reason it spun, i.e. low oil pressure at the top end, blocked oil passage, cap not torqued down correctly

 

2.3L Duratech heads do not have cam bearings the cam sets right on the aluminum journal.

 

Well thats F'ed up
What happened to engine engineering while I was asleep??

Did read about no set keys on cranks and cams, figured that was just a myth, now no cam bearings............so you don't rebuild an engine just buy a new one
Hope the head and cams are cheap, I know bearings were

Joking aside, yes, OHC engine's with aluminum heads are going to no Cam bearings but didn't think the Mazda L was one of them

 

Well I can say the engine has just under 7,000 miles on a complete rebuild and I had a machine shop rebuild the head and told them to tell me if anything was wrong with it and they said all was fine, I did not see anything wrong with head when I built the engine so its been running fine but for the smoke from the valve seals that the head machine shop put in. What's odd is the cam bearing caps do not look bad but a few of the head journals do. Either way the cams are going back in this is my work truck and it has to be on the road Monday.

 

Well I found out the head was cracked and went and bought a rebuilt head then a rod cracked at the piston pin and and totally damaged the cylinder beyond repair. Things sometimes just suck and turn into a **** show.

Tune in on this thread for the next journey of my truck....more stuff good and bad. https://www.ranger-forums.com/dohc-2...uratec-167390/