WTF: Excessive crankcase pressure on rebuilt engine

[turbofabricator]

The best way to seat the rings is to put some boost to it. (that, as Donnie stated, increases cylinder pressure, which forces the ring against the cylinder wall). On an engine dyno, a new engine will smoke out the breathers until you put some water brake load to it. If an engine is assembled correctly, there is NO reason the car can't be raced after the initial heat cylcle and oil change. We just finished an engine on a Monday evening, and ran a 10.2 @134 on Wednesday night. Still runs good.

 

[L8TRH8R]

We put 5-8 psi on it after initial heat cycle/oil change just by power breaking the car in the shop.

 

[tcgn]

Thank you for the replys.
What is the definition of heat cycle/oil change? Does that mean after start up, let it idle to normal operating temp.,shut down and change the oil/filter (due to assembly lubes), add ZDDP with fresh oil and then drive it hard with 5to 8 psi with some deceleration. Freeway is 4 blocks away from my shop. Should I drive it on the street or freeway to break-in the rings? Freeway will have constant cruising RPM's @ 2,400.
Please advise. Thanks

 

[turbofabricator]

Here is "my" process for engne start up after re-build:

Start engine and bring RPM up to 1800-2000.

Check for leaks, and any other issues. Fix any "issues" before proceeding

Keep RPM at 1800 or so for 15-20 mins even with a roller cam.

Shut off engine.

Drain oil and pull filter.

Cut filter apart and check for COPIOUS amounts of debris. THere will always be some debris found in filter. I am looking for meatl debris, i.e. bearing particulate matter.

Install new oil and filter.

Start engine, let warm up to operating temps. Vary the RPM a little while doing this.

Put car in gear, step hard on brake pedal, make sure there is ample room in front of the car to stop if there is a braking issue.

Slowly bring the power up against the torque converter to about 2-4 psi boost, then SLAM the throttle open and let the tires break loose. THAT will seat the rings. If that doesn't seat the rings, then something wasn't quite right.

Take car to track and let 'er RIP! Nothing else to do as far as break in is required. If the engne builder tells you other wise I would be suspect of thier abilities. Top Fuel cars are rebuilt in 45 minutes and then have 8,000 HP put to the tires after a few minutes of run time.

Print this and hang on shop wall for future reference.

 

[Alky V6]

I load rings as soon as possible. On the first startup. I don't wait to change the oil.
During cam break-in, make sure the timing and a/f ratio is safe, check fluid levels, check for leaks, check temps, make sure oil is staying clean (no water). As soon as cam breakin is completed, get it to the street and do a series (I do five) of low boost accelerations with 45 seconds of normal driving in between. The normal driving should include varied throttle positions, including stop and go. Avoid one throttle setting, such as freeway driving. While you're breaking in the rings, watch your oil pressure and water temp. If either looks funny, get back to the shop, or if real bad, stop and get towed back to the shop.
After you're done with the ring break-in, change the oil and filter.
I like to periodically load the rings on subsequent drives. Slowly working the power level up, watching fueling with a still safe timing setting. Don't baby the engine.
Try to stay away from a/f mixtures that are too rich. That can wash the rings and prevent a proper ring break-in.

edit: Always cut filters open for inspection, like turbofabricator suggested above.

 

[tcgn]

Hi Donnie,
the cam is already broken in with 370 miles on the old damaged block which is not a 109 block. Should I still break in the cam again with this new rebuilt 109 block?

 

[Chuck Leeper]

So, what was determined to be the problem???

 

[RmvBfrFlght]

Hi Donnie,
the cam is already broken in with 370 miles on the old damaged block which is not a 109 block. Should I still break in the cam again with this new rebuilt 109 block?

No need to. Just be sure that the lifters are placed on the same lobes and that they are well oiled.

RemoveBeforeFlight

 

[tcgn]

Hi Chuck,
The crack on the block is on both sides starting from the stud area and spreading outwards. That block is fatique and I wished I bought another block to start the rebuild. For my new rebuild, this shop had the torque plates. I just pick up my motor Sat. morning and hopefully things will go smooth from here on.