Sudden Increase in Blow-by

[PotvinGuy]

Thanks for the input, Kerry. I'm definitely going look into a different PCV set-up. My current set-up has never been able to keep up with the blower. And as I said above, I don't think my rings ever seated properly. Head comes off tomorrow... we shall see!!

When I first built my car, I just used big hoses going from each valve cover down to the ground. They used to call these road-draft tubes. But the oil vapors got all over the undercarriage, so I cleaned up my act.

Oh, I use clear tubing on my present setup so I can see what is going where.

 

[one finger john]

I would have to say one of the most prevalent causes of rings not seating is cylinder washing down with gasoline.

Saving money can take the long route as far as block prep but might be the least expensive and most rewarding.
How? Taking the block down and having a very light glaze buster hone put on the cylinder walls. This will be done by hand, not machine. A trained, talented machinist who knows his stones and how to operate a three stone hone. No need to replace cam bearings. No need for total hot tank dip. Just pay attention to doing the job right. Cleanly.
If the pistons look to be in good shape, they haven't collapsed, piston to wall clearances are good, ring land clearances are in spec (if they are over size or worn, new piston time, .040 over) pin clearances are good,, you can run them and save money. You could have the pistons friction coated and the tops coated with anti-detonation coating. Believe it comes in a nice gold color. Might send out the heads also and do the chambers and valves the same. If the heads are good and the guides are tight (in a good way) you would have extra protection against detonation. Just use a slap stick to lap in the valves & seats.

More in a few minutes.

John

 

[choppedtop]

John, wouldn't a ball hone work to bust down the cylinders.? That is what I used in my harley shop, after boring, then hone to correct size, then cross hatch with a ball hone.

 

[one finger john]

And here is where I might get some comments. I would run a quality cast iron ring. I would hand fit the rings after the block has been honed. Instant break-in on start up.
Set everything up so you can go for drive for about an hour (varying speeds and load) as soon as the engine is started. Go for that drive when it is cool, say 9:00 pm, no traffic. Just cruise and break in. Blower should take care of the different loads on the engine.
Come home, drain the break in oil (std. 30 wt. non detergent) & filter. Check the filter (cut it open) for debris (shouldn't be anything, just an engine refresh, no modifications). Put in fresh quality 30 wt. standard non detergent.
Let it cool over night, re-torque the heads,(might even drop the pan and re-torque the rods & mains, optional if they loosened on first build. If the rod brgs are ok, run em. If the mains look good, run em.
No need to spend extra money.

I'd also run an A/F meter. If you have hydraulic roller lifters, run a programable knock sensor.
I'd also run head studs.

O.K. guys did I forget anything?
Flame suite is on and sealed.

John

 

[one finger john]

Yes, choppedtop, you can use a ball hone. I prefer a three stone hone for accuracy and straightness of bore. This is a very light hone, not to remove material, but to lightly break the glaze. maybe two swipes or three at most. Like I said a talented, old school machinist, that can make ice cream out of shit. That works with his hands.

 

[Screaming Metal]

Ball brush hone, commonly called a glaze breaker, is Fine as long as you start out with a decent surface. A 3 finger hone is fine for knocking down the high spots.
A good heavy duty machine hone driven by a 1/2" drill, the kind that clicks on the knob, and the 4 sunnen honing blades, is the way to go.
After a good, straight boring job getting it close, then the machine hone within about .001, sneaking up on it with the 3 blade, put the crosshatch on with the brush. Thats the way I used to do it back in the day....
Now, I do everything with the Sunnen block machine with the torque plate in place.

Yep on a good ole hotrod 350 with a blower thats not super duper fancy, run a chrome moly top ring, cast iron 2nd, and a good expander oil ring.
The top chrome moly will take the punishment, and do a good job of sealing, the cast iron 2nd will seal quick and lap itself into the wall and give excellent sealing/long life, and the oiler will keep the bore lubes correctly. That is a good compromise that will last a long time....
Straight cast iron rings just wear out so quick in todays motors with the crappy fuel and high water content.
Dual molys will wear out your bore quickly, in less than 80-90,000 miles.
But, in a hotrod that doesn't see that many miles, just make sure the job in done correctly and competently and all will be good.
Hope its the head gaskets....
When you had the motor built, did you sonic check the wall thickness? Some 350's had a lot of coreshift, and under boost pressure it would do a hairline down a bore....causing the exact symptoms your experiencing but it'd overheat....
I still believe a headgasket....

 

[Screaming Metal]

One other thing, if your running the low tension rings, and the hone surface was too smooth, and you didn't get the motor good and hot during the first few run-ins, rings not being seated could very well be your problem.
I use the breakin oils now, helps lap the rings in so they'll seal in the bores, then I change the oil 2 times close together at 500 then at 750 miles....helps get all the wear in stuff out of all the cracks and crevises inside the motor....

 

[one finger john]

S.M I bow to your expertise and experience. Chit chat is nice but we will have to wait for tomorrow's disassembly

Cheese and crackers Lee, don't you work at night?

John

 

[Screaming Metal]

Hahaha....damn false teeth....yep, waiting.... gonna gum this burger now, see ya'll tomorrow. Gotta go torture a motor, in about 30....

 

[Lee_in_KC]

0900 Thursday, Sept. 24... It begins...

 

[one finger john]

Welp, ya got the ignition wires off! That is a start.

It is 8:18 am PST here in Los Angeles, CA eagerly awaiting the diagnosis (don't wanna say autopsy or post-mortem).

John

 

[Lee_in_KC]

Progress at the lunch break...

 

[one finger john]

Couldn't talk you into a complete car disassembly for some beauty shots and detail explanation?

Hmmm .... pretty please?

John

 

[Lee_in_KC]

Well, I don't know whether to be happy or frustrated. Head gasket is in perfect shape, looks almost new. #1 cylinder looks fine... no cracks, scratches or anything! Piston looks fine, from the top at least. If I have a broken ring, what would be the indications? Am I going to have to pull the piston to check?

 

[one finger john]

A yup. Drop the pan, pull the piston. Could you give us a better picture of no. 1 cylinder wall?

John

Check valve guide seals, heck replace them. Also check for valve guide wear.

 

[Lee_in_KC]

There is a little baked on oil in the upper right of the top of the piston. None of the other pistons have this.

 

[Lee_in_KC]

Unfortunately, I only have an iPhone for pix. My good DSLR is lent out. Here's #1 cylinder. There are some very faint verticle marks in the same quadrant as the oil deposit on the piston. I can not feel them with my fingernail.

 

[one finger john]

You are right, there is excess oil in the cylinder. Either from the rings or valve guides or both.
Don't forget that well lit shot of no. 1 cylinder wall. Could you have rattled the engine at one time in the past?

 

[one finger john]

When viewing no. 1 cylinder, with piston all the way up, is that a rock or small pebble @ approx 3:00 position. Have you run the engine without air filters?

How do the blower rotors look? Scraped up from debris? Can you see inside the case?

John

Anyway, you have been very cooperative, thank you.

Now to work and pull the pan & piston.

 

[one finger john]

Been feeding the engine Boraxo to seat the rings?