Don Terrill’s Speed-Talk

I checked oil ring tension with a standard (22-24lbs) and a light (15-17lbs). I ran the light for about 130 runs with no smoke and decent power. Some people think I have an oil problem based on the piston and chamber shown below. I'm willing to run the standard tension ring if the consensus is that there truly is an oil problem. I can't tell if it's just to rich or if there's oil getting to the chamber. Slight oil in the cylinder will probably kill more power than the extra drag on the standard rings. I run a pan evac system that pulls 6-8 inches going down the track. What do you think?
[img][img]http://i246.photobucket.com/albums/gg81 ... C00631.jpg[/img][/img]
[img][img]http://i246.photobucket.com/albums/gg81 ... C00633.jpg[/img][/img]
[img][img]http://i246.photobucket.com/albums/gg81 ... gkb7es.jpg[/img][/img]

How much power does your engine make?? how big is it(cubic inches) When I used to run pistons that looked like that, putting a big radius on all the shart edges was an immediate turn on( 40 HP )Based on your pictures, I say that you have an oil controll problem.How much timing does it want ??

JOE SHERMAN RACING ENGINES

I would look at your valve guides first. We run much lighter and no problems. Was the cyl leakage good?

Tom

What is that beside the spark plug, A knurled piston ? I hope thats not what your running.

Are you running a "out of the box" 3 circuit dominator???

i was kinda in the same boat as you, i ran low tension oil rings;fish scaled @12-15 lbs of tension,i had a engine smoking problem,even had oil all the way up in the intake ports i changed to a set of total seal rings with a med tension,[never did fishscale them and they wen't in with a lot more drag than before] well what do ya know the smoking stopped,oil not in the intake ports and the car actually ran faster...if ya believe that.in my opinoin you probably don't need a really low tension ring pack to get good performance,maybe unless its a all out max effort deal.

bigjoe1
PostPosted: Sat Jul 26, 2008 3:11 pm Post subject: BB Chevy
How much power does your engine make?? how big is it(cubic inches) When I used to run pistons that looked like that, putting a big radius on all the shart edges was an immediate turn on( 40 HP )Based on your pictures, I say that you have an oil controll problem.How much timing does it want ??

I'd say 550-575 HP, the car weighs 2800 and goes 10.0's at 132. It's a 427 standard bore. I run the timing at 36-38 with a locked HEI. I thought the sharp edges had a enough radius, but I can round them some more.
Thanks Joe.

3V Performance
PostPosted: Sat Jul 26, 2008 3:31 pm Post subject: oil
I would look at your valve guides first. We run much lighter and no problems. Was the cyl leakage good?

Tom, The valve guides checked good. Leakage wasn't as good as I normally get, but it wasn't horrible. It was 5-8%. It looks like you lean toward an oil control problem too.

BH
PostPosted: Sat Jul 26, 2008 3:38 pm Post subject:
What is that beside the spark plug, A knurled piston ? I hope thats not what your running.

It is a knurled piston, but it's not one of the ones I'm running. If done correctly, knurling works well. It ain't easy to find a shop that does them correctly though. Do you think I have an oil control problem also?

Beretta
PostPosted: Sat Jul 26, 2008 3:42 pm Post subject:
Are you running a "out of the box" 3 circuit dominator???

The pics are with a 2 circuit Mighty Demon that runs fat at idle and part throttle. Maybe my EGT gauge is way off. Do you think it looks more like super rich and not oil?

I appreciate the responses. I took the oil expander from the standard set and put it in the bore and it was snug when squared. The light tension expander won't stay in the bore, it just falls through. That can't be right can it? They have 133 runs on them.

Do you tune for best performance or do you just run it as is ?? ( bracket racer )When I used to run BB Chevys, I ran the timing way up there ( 42-44 )If you want it to go faster, you could learn alot on an engine dyno. What spark plugs fo you run ??

JOE SHERMAN RACING ENGINES

The other thing to check is your piston to wall clearence. Do you know what your final bore size was? Also what did your piston measure?

Tom

bigjoe1
PostPosted: Sat Jul 26, 2008 5:25 pm Post subject: BB Chevy
Do you tune for best performance or do you just run it as is ?? ( bracket racer )When I used to run BB Chevys, I ran the timing way up there ( 42-44 )If you want it to go faster, you could learn alot on an engine dyno. What spark plugs fo you run ??

Joe, I used to run a lot of timing when I was running B/MP back in the early 70's. This is a bracket stone that needs to go rounds. I run NGK B7ES. Have you ever put a light tension expander, by itself, in a bore? This one will not stay in the bore. I think that might be my problem. Joe, you think I should radius the edges a lot more or a little more?

3V Performance
PostPosted: Sat Jul 26, 2008 6:16 pm Post subject: oil
The other thing to check is your piston to wall clearence. Do you know what your final bore size was? Also what did your piston measure?

Tom

Tom, I run .006 piston to wall. These are some old Manley hollow domes. What do you think about the expander having zero radial tension? You've probably never stuck one in a bore. Maybe I'll call Ackerly and Childs and see what they can do for me.

farrigno
New Member
New Member


Joined: 01 May 2008
Posts: 8
Location: mass

PostPosted: Sat Jul 26, 2008 4:34 pm Post subject: Reply with quote
i was kinda in the same boat as you, i ran low tension oil rings;fish scaled @12-15 lbs of tension,i had a engine smoking problem,even had oil all the way up in the intake ports Shocked i changed to a set of total seal rings with a med tension,[never did fishscale them and they wen't in with a lot more drag than before] well what do ya know the smoking stopped,oil not in the intake ports and the car actually ran faster...if ya believe that.in my opinoin you probably don't need a really low tension ring pack to get good performance,maybe unless its a all out max effort deal.

The difference between yours and mine is that mine doesn't smoke at all, zero, nothing. If it did, my decision would be easy and I know you'll go faster with no oil in the chamber. Oil in the chamber is death to horsepower. Did your stuff look similar to the pictures posted?

I'd round them pretty good. The flame front being able to hug the piston as it travels across the piston is very important. Sharp edges will promote turbulance in the flame front, which will trim hp from your engine. You wouldn't want turbulance in your intake runner, would you? This is as important or even more. Lay back the valve reliefs a lot, also. You shouldn't be trimming much compression, but if you do then deck the head some to get it back. IMO...wherever the flame isn't hugging the piston it isn't getting full force pushing the piston down the hole during combustion.

This is all just my opinion, but hey...I'm just a want-a-be ...lol

Don

Ace Rod Shop

actually ron my chambers looked wet like yours and my plugs looked wet/shiny too.

Please tell me that someone did not knurl the sides of those pistons.

Strange Magic
PostPosted: Sat Jul 26, 2008 10:12 pm Post subject:
Please tell me that someone did not knurl the sides of those pistons.

Those pistons are knurled, but they aren't the ones being used in this motor. By the way, knurling is fine if it's done right. You have to go back and smooth the knurled edge so your left with only the beefy part of the displaced metal. You can double the life of your piston if you get a craftsman to do it.

want-a-be
PostPosted: Sat Jul 26, 2008 9:22 pm Post subject:
I'd round them pretty good. The flame front being able to hug the piston as it travels across the piston is very important. Sharp edges will promote turbulance in the flame front, which will trim hp from your engine. You wouldn't want turbulance in your intake runner, would you? This is as important or even more. Lay back the valve reliefs a lot, also. You shouldn't be trimming much compression, but if you do then deck the head some to get it back. IMO...wherever the flame isn't hugging the piston it isn't getting full force pushing the piston down the hole during combustion.

This is all just my opinion, but hey...I'm just a want-a-be ...lol

Don, Does it look like an oil control issue to you? What does "lay back the valve reliefs" mean? Do you mean the wall of the arc, where the relief meets the quench pad? As far as compression goes, I've got more than I want anyway. When I hand massage pistons, I always worry about getting all 8 the same. That's why I just barely smooth out the sharp edges. We used to try to leave the exhaust side shaper than the intake side of the dome. Is that old school and no longer true? HELP ME Don. I've got some good pics of Grumps small block stuff from the old days. I'll have to dig that book out.