(Engine Trashed?) Thread of Unfortunate Events

Do you think you want to just buy an engine from a wreck and be done with it?

 

Probably but honestly I enjoy this type of stuff. I'm an industrial engineer so when things break I like to tear down and find what broke and why. Pulling the heads off I can probably do in the next hour or so and inspect a little deeper.

 

I will say something to note is the whole bank 2 is covered in oil.

 

Well found the misfire on cylinder 4.

 

If only one bank is covered in oil, then perhaps it’s a ring(s) or valvetrain issue on that side. Perhaps there is oil in the catalyst system as well?

Wouldn’t the combustion process go lean if oil is present?

 

I sent photos to the shop..this was clearly done during reassembly of the heads. This only relates to the misfire on cyl 4. I still have a loss of 50% in cyl 6 probably through piston rings. I could loosen the cam and slip the rocker back on to get rid of the misfire and limp mode. Then put thicker oil into the engine and see if it will get me by for a while? What would you guys do?

 

Does anyone know if I can just loosen the cam caps to squeeze the rocker back into place then torque them back down without issue?

Update:
I loosened all the bearing caps and was able to flex the cam up just enough. It didn't take much and in the process I had 3 more rockers pop off when I lightly touched them. Finally was able to get all 4 rockers back in place lol.

 

Now gotta torque it all back down. They seemed over tight for sure. I'm going off of this spec.

 

I'm learning a lot from this. One thing I've just found is that these engines can spit rockers out if you exceed 6400 rpm. I also learned some on the whole valvetrain setup. Interesting setup they use for the hydraulic lash on the lifter. Glad to see it didn't tear anything up.

I find it interesting how only one bank has oil in the intake. Not sure how that could be.

 

Yes...that's very strange. I don't understand why. Even if oil is spilling from cyl 6 rings ALL intakes should look bad. I will say that whole bank was misfiring because of cyl 4 rocker issue. So maybe it's less oil and more of a burnt look. There is oil yes but the discoloration might just be misfire heat? Not sure.

Also not sure if RPM kicked it out or if the shop that did the valve job failed to install it.

 

I think it takes more than 6400 rpm to cause that. Other Toyota engines use the same rockers and are allowed to go up to more around 6800-7000 rpm stock. But it probably does start to become a problem somewhere up there.

 

More to do with the springs. @sherwoods_Fleet did they use stock springs? I know the valves are custom?

 

That would depend on the hydraulic adjusters used, and valve springs. Other models with a higher rev limit would use different adjusters and springs I would assume. If he has the stock Tacoma items, anything over 6400 would be open to failure.

One would hope it wasn't valve float that caused the rocker to spit out...and hopefully not the reason #6 fails compression and leakdown.

 

Tacoma, Sienna, Avalon, Camry, Highlander all use the same valve spring. Not sure about the middle 3 but Highlander has the higher redline. I have heard the only differences in redlines is due to how Toyota wanted to tune them per use case. Not that there were mechanical differences making one more capable for revving higher than another.

 

They retained the original springs.

 

Got delayed, torqued everything down and was ready to install the intake and realized I trapped a connecter inside the valve cover. Had to back track to pull the cover back off.

 

Test drive went good. Couldn't drive it much and stayed 5k rpms or less and it could handle higher rpms much better. Definitely drives better on the high end. The low rpms it's a little jerky and sluggish. Either from the loss of compression on 6, the ecm needs more time to relearn or the valve in the intake I removed makes it sluggish. As of right now it's much more drivable though with the rocker back in place just not 100%. Also I should check for vacuum leaks too.

 

What's the thickest oil you guys would run in our motors? I don't want to damage any pumps but I'd like to attempt to seal cyl 6 rings as best I can.

Also remember this is basically a trash motor at this point so I'm not too concerned about damage long term. I'm actively looking for a low mile motor to engine swap.

 

Up to 15W-40 is approved by Toyota quietly. Honestly, even 20W-50 would be fine if it isn’t 10° out. They are really not all that different. I’d probably keep to 15W-40 just for the oil options.

 

Awesome, thank you! I'll pick some 15w-40 up tomorrow and drive the truck around for a bit see if I can clean up the compression enough to daily drive for a while.