Jeep Strokers

Shouldn't be the thrust bearing. We checked the tolerances on it and it was in spec and there was no play in the harmonic balancer so it didn't seem like the crank was moving.

Were those checks done before or after the problem arose?
Check the main bearings, they could b on the way out allowing the crank to bounce around. There is much more force on the crank when its under load then wiggling it by hand. Dont forget to look for any nics where the seals ride also.

A big thanks to O-Gauge Steamer! I think we may have figured out a solution to the problem. Made a new vacuum port in the throttle body spacer to produce a higher vacuum in the PCV system and installed a Moroso air-oil separator in line with the rear PCV elbow on the valve cover. We sealed off the old vacuum location on the intake and now the PCV system gets it's vacuum from the air inlet on the throttle body spacer. This along with drilling out the opening on the rear elbow PCV increased the vacuum from 4 inches of mercury to 12, increasing the vacuum in the crank case by 300% and the idle is still fine with no engine codes.

Today we did a warm "dry" compression test on the motor and there was only a 7 psi difference between the highest and lowest reading which equated to a mere 3.8% difference and the average 180 psi equated to a 10:1 compression ratio which the motor was designed to have from Titan. Tried a "wet" run on one cylinder but there was no difference and didn't see any reason to do a full wet run since all cylinders were well within spec.

Going to monitor the seals now for any more leakage and maybe replace them one more time.

Does anyone see any benefit to still doing a leak down test?

BADASYJ, that's a good point. We checked the thrust bearing tolerance and the harmonic balancer for play before the problem with the main seals arose so that's probably a good thing to check again along with the main bearing tolerances. The motor does only have 12k miles on it though...

Here's a pic of where we tied the new vacuum source into the throttle body spacer and closed off the old inlet into the intake.


Here's one of the Moroso air-oil separator.

That makes no sense at all.. If there was excess pressure it would have vented to the front valve cover breather, pushing oil/fumes into the air filter.

ScienceguyXJ wrote: Here's a pic of where we tied the new vacuum source into the throttle body spacer and closed off the old inlet into the intake.

A different vacuum source 3-4" apart is so different? Both locations are below the TB and isolated from other draws.
Maybe drilling out the PCV elbow would make such a difference.

It makes a slight vacuum difference of .5" of mercury having the vacuum port under the TB and not on the intake. Small difference but as easy as making the custom TB spacer was it see it as worth it plus we have a way we can still increase the custom TB spacer vacuum pressure up a little more.

It's been a few weeks now and the leaks have stopped. Increasing the PCV vacuum worked!

Awesome