Help me evaluate these photos. Chamber and Piston

user-9274568 · Post by **user-9274568** » Sat Feb 23, 2008 3:46 pm

Darin is big on touching the seats after dyno and runs. That was my plan. Plus I just wanted to see what was going on..

Plus I had some time before I started racing.

want-a-be · Post by **want-a-be** » Sat Feb 23, 2008 4:49 pm

Few more questions for you bud. Were the intake runners on these heads washed before you posted them? Or did you pull the valves and shoot them for us?

If it's the latter then It doesn't look like your sucking oil through your vavle guides. But I'm not able to see the oil drain backs from your Rocker area. Looks like it could fill.

I was in on an engine build once that the Springs themselves were acting like a hydrolic pump near peak lift and forcing the oil past the seals. The fix was to properly mill the valve spring pockets near the cover rail to better evacuate the oil. also ran a pump line to oil drain holes in the back of the heads. This happened on what I think was the second generation B-1 heads. They were being rushed through and all the proper details was initially bypassed. Was a mistake.

Thanks, Don

Strange Magic · Post by **Strange Magic** » Sat Feb 23, 2008 8:10 pm

Just by looking at the exhaust ports this engine is down big time in power. Oil is heading right up through the rings and into that chamber. It's not uncommon for your tune up to be a tad lighter on the jetting than what it really should have been. Your mixing oil with fuel and air in that chamber.
Forget a leak down, it means nothing in this situation and chances are is that the leakdown will actually be better when oiling (it's no indication). The only way to determin if an engine is oiling is the color of the exhaust port and a feel (from experience) of the amount of drag that piston should have with just the expander and two rails on.

Just out of curiosity, what is the stroke in this engine and deck height? Lets see a picture of this oil pan. Bigger is not always better!

RW TECH · Post by **RW TECH** » Sat Feb 23, 2008 8:37 pm

Did it look oily when it came off the dyno?

user-9274568 · Post by **user-9274568** » Sat Feb 23, 2008 8:46 pm

I'll try to post a photo of the pan. It's a full box, sectional type.

The deck height is 8.830
3.700 stroke

The shots were taken the second I took the head off. I just took the springs off for that shot, I didn't clean anything..

Actually the exhaust looked perfect to me off the dyno. Nothing like the photo.

No vacuum and a 4.157 oil ring in a 4.165 hole could be a problem..

MaxFlow · Post by **MaxFlow** » Sat Feb 23, 2008 9:28 pm

Looking for a couple hp with the oil expander probably cost ya. No you'll be timid to put it back together like that to try it the second time? I wouldn't. I'd put it together so it worked for sure. Thin lowtension ringpacks and big rpm with low vac and fueling issues = oiling problems like you have.

I was just asking firing order to possible address that burn issue. Is this a wasted spark setup, coil on plug, mag, or what?

user-9274568 · Post by **user-9274568** » Sat Feb 23, 2008 9:33 pm

I may not put a 57 back in it, but it's got to be low drag.

This is a front MSD dist with a crank trigger and a Digital 7 box.

I still think it has too much oil in the pan.

I'd bet it's down 10-15 hp because it doesn't have 15 inches.

Windsor377 · Post by **Windsor377** » Sat Feb 23, 2008 11:12 pm

Ron E wrote:Wow!
I hope the general enthusiast who happens by this site can comprehend what he's viewing. Just a few years ago, you were on your own with stuff like this. In one little thread, xenginebuilder and Ed laid out specifics that some engine builders, over an entire career, could easily have missed.

You are absolutely right. This place is a such an invaluable resource. I wish I new about this place back when I was dealing with this:

The culprit was the second ring.

beth · Post by **beth** » Sun Feb 24, 2008 12:13 am

Looks like one intake valve was hitting the piston. The heat bluing of the edge indicates it may be bent.

beth

needforspeed66gt · Post by **needforspeed66gt** » Sun Feb 24, 2008 1:04 am

beth wrote:Looks like one intake valve was hitting the piston. The heat bluing of the edge indicates it may be bent.

beth

Yep - I see that too.

Barry_R · Post by **Barry_R** » Sun Feb 24, 2008 8:13 am

Quench sure does not mirror the chamber shape on the piston...
Plug too shallow is pretty clear...
But those are not the real problem...

I'm more curious about your wall comment & finish. Rings will scrape to an extent in both directions. Super smooth & shallow wall finishes will not give the oil anywhere to go but up on the upstrokes. Cross hatch grooves serve a purpose.

What radial wall thickness is the oil ring? It's not just tension that makes sealing happen. Bore conformity is better with a thinner wall, allowing lower tension for the same scaping ability.

Have you pulled a piston? The face and sides of the rings could tell us something.

RW TECH · Post by **RW TECH** » Sun Feb 24, 2008 10:08 am

From the start I've been wondering about effects from 2nd ring & its end gap.

This is why I asked about the condition of the engine when it came off the dyno.

Chad, can you fill us in?

user-9274568 · Post by **user-9274568** » Sun Feb 24, 2008 1:22 pm

The engine has a .160 radial DMR top ring

It has a .170 radial IPC 2nd ring

And a .152 radial CUF oil ring with a min of .010 on the rails

Gaps are .022/.024

No valves are bent, they have been checked..

MELWAY · Post by **MELWAY** » Sun Feb 24, 2008 3:20 pm

Maybe try a napier 2nd ring next time round...

Keith Morganstein · Post by **Keith Morganstein** » Sun Feb 24, 2008 3:40 pm

The carbon marks at the gas ports are interesting. Thinking about it, pressure should be there and behind the ring on compression, power and exhaust strokes. Only on the intake stroke should there be vacuum pulling anything out.

Are we really seeing burned oil deposits entering the gas ports, not exiting?

How much oily crud is behind the rings?