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Why does Timinator reccomend top gap at 0.022 and second ring at 0.018" when everyone else reccomends larger gap on second ring than the top ring. Is this a typo or is there a reason?
 

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Why does Timinator reccomend top gap at 0.022 and second ring at 0.018" when everyone else reccomends larger gap on second ring than the top ring. Is this a typo or is there a reason?
You could pm him and ask him...as far as I know he is still a member here. I couldnt tell ya how often he does or doesnt log on here though.
 

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Boat Nut
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To minimize pressure build up between the rings at RPM, the second ring is not only for combustion, but its the final step in oil control.
 

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The article is old. Situations in a car app are different than on a jet too. The top ring in a jet app runs hotter than in a car app and as such it will "grow" more and end up with a smaller gap than the second ring anyway. Our research continues to find out how much different the gaps need to be. The phone # is correct, and I don't have much time to be on here. Thanks for asking. TIMINATOR
 

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B1 Racing
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Dont believe everything you read online!!. Check with a piston manu. or ring companies
 

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funny :)bit


and you are a engine guru:no:


maybe im wrong :thumb:
 

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First off! CS is right! check with your'e ring supplier. There are alot of factors that define what you should run. Nitrous, engine temp,piston type,RING type, plug heat range and induction. As I worked for one, the standard recommended starting point will be .004 to ,0045. which once you do the math will infact be in the area of what everybody is talking about. M
 

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First off! CS is right! check with your'e ring supplier. There are alot of factors that define what you should run. Nitrous, engine temp,piston type,RING type, plug heat range and induction. As I worked for one, the standard recommended starting point will be .004 to ,0045. which once you do the math will infact be in the area of what everybody is talking about. M
.004 x the bore diameter?
 

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.004 x the bore diameter?
That's what I was getting at, but other factors may come into play. NOS for one. you are tossing a cooling agent into an already hot area and expansion rate may differ. I admit I am no NOS guy and don't know the results of the bottle but I will say I can never understand a wider top-ring gap than the second. Unless you want to vent to the crankcase and create the need for a puck-tank or Pan-evac! M
 

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The top ring will always run hotter than the second ring. Hotter means more expansion. More expansion means less resultant end gap at operating temprature. This means that at operating temprature the top ring gap usually ends up with a tighter end gap than the second ring. The second ring is mostly only for oil control, it has a tapered face to "ski" over the oil on the cylinder wall on the upstroke and scrape the oil back to the pan on the downstroke. This is why with any modern engine with a decent ring pack will only show wear at the bottom of the second ring(it will be shiny). It is said that the pressure buildup between the two top rings will cause the compression ring to unseat causing the top ring to flutter in the bore on the upstroke. I first recognized that condition in 1981 when I tried a two piece second ring in a race engine in my Pinto. The block was well prepped: torque plate honed and properly wall finished for the ring pack as proscribed by the manufacturer. Upon the first and subsequent teardowns the cylinder walls had bands of shiny (signs of the ring breaking in on the wall),alternating with bands of dull (unmarked cross hatch). Photos were sent to the vendor and several other ring and piston mfgrs. Evrybody but the funny ring mfgr. had the same story: ring flutter , and the explanation that the 2nd ring is for oil control. The cause was pressure build up between the rings. I replaced only the rings with a moly set and re-torqueplate honed the block lightly. The car ran faster, and the walls then looked normal. I have spent much time on research of ring gaps and ring types, leakdown rates, and Horsepower production in relation to observed leakdown. We typically try any newest, latest thing on our own shop engines, but have always come back to a 5 step plateau hone with a torque plate, and moly or plasma moly rings. By the way, our test method is to use our tried and true wall prep and rings in one bank, and the "flavor of the month" idea on the other bank. Frequent leakdown checks and good record keeping tells all. If a better way comes along, we will use it, until then we keep trying the new stuff, but building the customers motors with what we know works. The funny rings were mostly all patented and first used in the late 1800s to early 1900s to keep lubricating oil out of the coal miners air supply with the piston type air compressors that were commonly in use. Now that ring materials and machining techniques are better, everything that was old is new again. Be aware of the fact that what works in a dyno "challenge" or drag car, only has to make good power for a few MINUTES of run time. You will typically have more full power run time in a boat the first or second outing than a drag car sees all season. Just things to consider... TIMINATOR
 
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