Pressure under valve cover

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HCP2311

HCP2311

Joined
Apr 18, 2024
Threads
11
Messages
54
Location
USA
After replacing the head gasket on a 93 (previous owner stated head gasket was blown) vehicle still will not run, has fuel, spark and bang. Did a leak down test today and verdict is C1,2,4 and 5 all leak to the valve cover, oil, gasoline and metal shavings present on new sparkplugs. C3 was clean and held pressure and I didn't see any reason to bother testing 6 by that time. 30psi on C2 actually pushed the piston down...

Since the engine has not been ran since the head was machined I'm chalking the metal shavings up to that, gasoline is probably from chasing spark problems the last few days and oil... I'm giving that to piston rings.

Does anyone else see a culprit other than bad piston rings for this? Oil in the cylinder and air flow from the cylinder into the valve cover?

P.S I'm looking at S&J Engines for a rebuild. Any thoughts on that or are there any business on here that would be interested?
 
CharlieS said:
I would make a hard stop until I was absolutely certain all metal shavings are out of that engine. That is a surefire way to destroy one fast.
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Well hard stop is where it's at because it's dead in the water right now. Beyond turning it over with the starter it doesn't run.
 
You should fill in some context. Miles prior to the rebuild, who did the rebuild, what parts were used for the refresh. OEM, aftermarket, etc.

But yeah, hold tight for now. You may even want to do a drain and strain on the oil. See if anything is in there.
 
The oil in it is new, I'm guessing that the owner that blew it up changed the oil when they removed the head. I bought the rig from a guy who had bought it head off. I replaced the head gasket and reinstalled/timed it per Toyota's instructions. (Using prodemand as I didn't have the fsm at the time.) I'm confident that it is timed correctly. While I don't know who did the machine work on the head, the head surface was visibly refinished and the valves operated smoothly. As far as I know it has not run since whatever happened to it happened. Personally, I think the owner that damaged the vehicle tried to hide the damage; that might be the guy I bought it from or it might the guy before him like he states.

There is a surprising amount of mud and sand in places and the entire floor of the vehicle shows noticable flood damage. What I think happened is someone buried it in a mud hole blew it up, pulled the head and sold it claiming it had a blown head gasket. In the pile of parts I received there was a used composite gasket that didn't really look like it was blown.
 
I would agree rings are bad, still very confused how you got metal shaving between the head and block if a machine shop machined it and reassembled it they would be responsible enough to clean out the shaving from machining atleast I would think. I have never heard of the engine builder S@J do you have experience with them? Do they use Toyota parts?, keep your head up sounds like you’ll figure it out.
 
Fj80oregon said:
I would agree rings are bad, still very confused how you got metal shaving between the head and block if a machine shop machined it and reassembled it they would be responsible enough to clean out the shaving from machining atleast I would think. I have never heard of the engine builder S@J do you have experience with them? Do they use Toyota parts?, keep your head up sounds like you’ll figure it out.
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I was told to expect metal shavings after any kind of machine work and do a fresh oil change shortly after. I don't have any experience with S&J, I just found them through google. I don't think I have the skill to do a full rebuild to the level of quality I would want, and I don't have a shop in which to do the work. I'm working out of a wheeled tool cabinet in the drive way. I actually would not have bought the vehicle if I had known that the in-law who offered to rebuild it would disappear on me. Its been a learning experience for sure!
 
That sucks on the engine! They are awesome trucks but take a lot work to get them up to a solid baseline then routine maintenance to keep them reliable. I rebuild 1fzfe’s and disagree on the metal shavings maybe a little wear when new bearings are installed but that’s more like a powder than shaving and that is very very minimal. If you’re looking for a rebuilt motor let me know I have a couple in various stages of rebuild now. Pm me if you are interested.
 
a LITTLE oil glitter on a fresh rebuild is ok.
metal shavings you can feel between your fingers when you rub them together is all bad and I would be having a serious conversation with the machine shop about the quality of work performed and money i paid them..

On fresh engine rebuilds there is a ring break in or “ring seating” break-in. Hence why builders recommended varying RPM loading, no WOT pulls, and low mile oil changes the first 2-3 services.

I would want to see some pictures of the “shavings” if that is truly what it is..
 
DIRTBIKEUSA said:
a LITTLE oil glitter on a fresh rebuild is ok.
metal shavings you can feel between your fingers when you rub them together is all bad and I would be having a serious conversation with the machine shop about the quality of work performed and money i paid them..

On fresh engine rebuilds there is a ring break in or “ring seating” break-in. Hence why builders recommended varying RPM loading, no WOT pulls, and low mile oil changes the first 2-3 services.

I would want to see some pictures of the “shavings” if that is truly what it is..
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Glitter is probably a better description. I couldn't feel the shavings, I could see them in the oil/gas mix on my finger tip.
 
HCP2311 said:
Glitter is probably a better description. I couldn't feel the shavings, I could see them in the oil/gas mix on my finger tip.
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Ok good.
My recommendation is this..

Use engine break in oil with Zink additive. Or add zink additive to your oil. Run the rebuild for 500 miles. Change oil and filter.

Do a compression test on all cylinders and record results. If it fails test (below 120 psi) perform leak down test and record results.

Run for 1000 more miles and change oil and filter.

Perform compression test and compare results from last 500 mile test. Compression should be 120-170. With lest then 14 psi variance between cylinders. If it fails compression test perform leak down and compare results. (It shouldn’t at this point as it should be “broken in”)

Then pick a good PM schedule and stick with it. That should clear things up.
 
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