Once Around the Block

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Windsor377

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What racer doesn't think engine stuff is cool? But to make serious HP you need a good starting point. It may seem boring to some, but without a good foundation, the fanciest set of heads are a waste of time and money.

I'd like to share a look inside a high HP engine and some understanding as to how these things work.

Here's the tip of the iceberg.

Please take note of oiling system things, shiney piston domes (key to my screw up last year), oiling system stuff and overall structure.
So here are a few pics to ponder for now:

http://members.aol.com:/windsor377/myhomep...epage/right.jpg

http://members.aol.com:/windsor377/myhomepage/left.jpg

http://members.aol.com:/windsor377/myhomep...epage/front.jpg

http://members.aol.com:/windsor377/myhomepage/top1.jpg

http://members.aol.com:/windsor377/myhomepage/top2.jpg

Discussions to follow...
 
Thats a interesting oil pan from stef's there. the custom make it on CAD? I have only seen them on hemi engines.
Tech portion: A standard box pan design would work well in controlling the oil during the course of the run, Yes, but, what is most commonly overlooked is the oiling that takes place at the end of the run. After run oil control is just as important as during run oil control. You can just as easily lose a motor during or after a run with out appropriate oil control. Control that oil Windsor :) ...so what happened last year?
 
I come from a N/A background. Low tension oil rings all around. Back cut top and second .043s and -.005" oil control. Guess what happened when the juice was turned on?

...Nice pan! Huh? But I'm changing it next go around to pull from the other side. It will shorten up the amount of line I need to run and react quicker. I'll try to get some pics to demonstrate. Plus I want to go with a 2 piece, to let me pull the pistons without pulling the block out.
 
This look fimiliar?
piston13.jpg


yeah, we come from N/A background too and stickin to it :) but if you must know, I find it helpful and entertaining when somthing goes wrong, thinking on the bright side of things :)

Has the way you hone your cylinders changed with the tighter tension? didn't know if you had any cross-hatch problems or not.

Definitly will have to show the new pan when it comes.
 
Actually, no damage, but not the power it should have made. The low tension ring set allows so much blow by that oils sprayed up into the cylinders, intake ports, etc...on cylinders not under pressure. The pistons you see in the links were covered in a black goop that wiped cleanly with a shop towel. Plugs fowled every run as well...all this even with a 5 stage oil pump!

I'm staying with .043 top and second, but no back cut, plus going to standard tension 3.0 mm oil control.

No change to the honig process. That is dictated more by cylinder rigidity, cylinder material and ring material. I go with a very coarse, soft hone...nice fuzzy cross hatch.

Take a guess as to what I call a good leak down number!
 
For you? good? haha, I will say around 10%

now I know back cut rings reduce radial tension, but what effects to you expect to come from the change in rings and tension?
 
10% would be primo! I generally get anywhere from 10% - 28%. Getting away from the back cut will increase radial tension. So my on the motor numbers will go down, even if my leak down numbers "improve". The resaon being, increased radial ring tension increases drag on the cylinder walls. Also, the little added weight of the non-back cut rings increases ring mass and thus ruduces the ability of the ring to react to the piston movement.

A buddy of mine drives a Pro Stock Ford in IHRA. Those guys get 50% leak down rates!!!! But remember, those measurements are taken while the piston is standing still. An 815 cid BB has tremendous piston velocity. The ring set needs to react with the piston and not against it. The set also needs to work together.

Ever dyno a set of zero gap or gapless rings vs a "regular" set? A stock engine may have shown a benefit. I've never seen a gain in a REAL race engine. Ever wonder why?
 
actually we have dyno'd reg and sealed rings but the sealed rings had a different cam in it, so its not verifileable. Thats what I have heard from others that there is no hp increase despite less leakage. Tell ya the truth, I don't know. Seems like they would keep the oil from milking to bad, especially in alky aplicaitons, but don't know why really.

That amazing how mass can overcome tension like that :)
 
Originally posted by NateDogg@Feb 19 2003, 09:01 PM
That amazing how mass can overcome tension like that :)
It's not just mass, but radial tension as well. Radial tension acts to restrict ring movement probably even more than mass once you are already dealing with small, light weight ring sets.

Real sealing occurs when the combustion gasses expand and get behind the top ring. Other than then, radial tension drags on the pistons free movement. Mass makes the ring slugish to react to the pistons free movement.

A low tension ring is quicker to react and adds less drag, but is forced against the cylinder wall under pressure. The engine in your cousins ED most likely has pistons with gas ports. Those ports help with ring sealing during combustion. A nitrous piston shouldn't have gass ports above about a 350hp shot, otherwise those ports will torch through...so maybe some radial tension is OK here.

Let the ring move freely when not under combustion forces. Otherwise, it is robbing HP.

In a nitrous engine, you could probably get away with a back cut top ring, IF it wouldn't give up under the heat and pressure.

However, the second ring does most of it's work by keeping windage from ever getting to the top ring and beyond. Nitrous or N/A. The thing with nitrous is, there is a LOT of windage and MORE if the ring package isn't doing it's job. That second ring needs to have some additional radial tension to keep that windage in check.

So the nitrous engine will have some "clumsy" rings in an "on motor" run, but when the juice is on, it will better use that juice.

As for gapless rings, I don't have scientific proof, but you can test it yourself with gapless or regular rings with too small a gap in the second ring. In a real race engine with serious cylinder pressure, it is my understanding and that of others I have spoken to about this, that no or little gap in the second ring causes build up of pressure behind the top ring and un-seats it...hurting HP.

Likewise the oil control needs to wipe the cylinder wall a little better in a nitrous application.
 
Originally posted by Windsor377@Feb 19 2003, 08:27 PM
A buddy of mine drives a Pro Stock Ford in IHRA. Those guys get 50% leak down rates!!!!
There's another contributor to this one.

Any guesses?
 
IHRA Pro Stock, have seen them once in action. If I remember right, the engines are fairly standard, small blocks, iron heads, around 9 to 1 compression(I think), no S/C or juice, so by running almost no tension they canestablish a higher rev and power is not lost as thought with 50% rates with the relative low compression. When my cousin raced his C dragster, he had a 300cid similiar to his B class engine, but he got the best hp by running just the top ring.

Sidenote: that engine is just sitting in the garage, I wish for a chassis to come along, that would be a great 1st dragster for me :)

Anyways thats my guess
 
Originally posted by Windsor377@Feb 18 2003, 06:18 PM

...Nice pan!  Huh?  But I'm changing it next go around to pull from the other side.  It will shorten up the amount of line I need to run and  react  quicker.
speaking of oil pans, care to guess what happened on this run with the oil pressure? This is data from a run last year, he launched at about 1.5 sec.
 

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Originally posted by Windsor377@Feb 19 2003, 10:21 PM
The engine in your cousins ED most likely has pistons with gas ports. Those ports help with ring sealing during combustion.
Yes my cousin does run gas ports, in fact 9 of them on a cylinder :) The shot is my attempt to scan a piston, haha, this is a 17to1 piston, and just like yours, .043 backcut rings. Notice the rings left from the valves, The Ti valves bounce off nicely.
 

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Originally posted by NateDogg@Feb 21 2003, 12:09 AM
IHRA Pro Stock, have seen them once in action.  If I remember right, the engines are fairly standard, small blocks, iron heads, around 9 to 1 compression(I think), no S/C or juice,  so by running almost no tension they canestablish a higher rev and power is not lost as thought with 50% rates with the relative low compression.  When my cousin raced his C dragster, he had a 300cid similiar to his B class engine, but he got the best hp by running just the top ring.

Sidenote: that engine is just sitting in the garage, I wish for a chassis to come along, that would be a great 1st dragster for me :)

Anyways thats my guess
...back sooner than I thought! Gymnastics cancelled!...gym flooded :( ...hope it doesn't cost too much to fix :unsure: ...

Nate, I think you're thinking of another class. IHRA Pro Stock uses those 5" bore space blocks with an 815cid upper limit. Huge bores in th 4.750" inch range with stroke around 5.750"!!!

These things get a lot of piston rock. An iddy biddy light ring will loose square real easily, especially if not under presure = real "bad" leak down.

On the other hand, if I were to build a "mild" engine, I would try to use those zero gap rings. Folks I have spoken to have seen 5 - 17hp gains in these applications.

I'm not surprised your Cousins engine made most power without a second ring. A low windage N/A engine should. That second ring help with endurance and "super charged" applications where windage is greater in that it "pumps" stuff away from the top ring. Where as the top ring "pumps" stuff toward the chamber. This is a result of the two rings having opposite taper.

...and if that engine looks too lonley, I'm sure the Dragster list a few you could drop it in!!!!...not in exchange for College though!
 
Originally posted by NateDogg+Feb 21 2003, 12:25 AM--></span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (NateDogg @ Feb 21 2003, 12:25 AM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin--Windsor377@Feb 18 2003, 06:18 PM

...Nice pan!  Huh?  But I'm changing it next go around to pull from the other side.  It will shorten up the amount of line I need to run and  react  quicker.
speaking of oil pans, care to guess what happened on this run with the oil pressure? This is data from a run last year, he launched at about 1.5 sec. [/b][/quote]
Not sure, what data aquisition do you use? Anyhow it looks like something droped off a little early...pick up?
 
Originally posted by NateDogg+Feb 21 2003, 12:54 AM--></span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (NateDogg @ Feb 21 2003, 12:54 AM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin--Windsor377@Feb 19 2003, 10:21 PM
The engine in your cousins ED most likely has pistons with gas ports.&nbsp; Those ports help with ring sealing during combustion.
Yes my cousin does run gas ports, in fact 9 of them on a cylinder :) The shot is my attempt to scan a piston, haha, this is a 17to1 piston, and just like yours, .043 backcut rings. Notice the rings left from the valves, The Ti valves bounce off nicely. [/b][/quote]
LOL!!! Ti can be your friend...if you treat it right...don't overheat or let it gall.
 
Originally posted by Windsor377@Feb 22 2003, 04:29 PM

Nate, I think you're thinking of another class. IHRA Pro Stock uses those 5" bore space blocks with an 815cid upper limit. Huge bores in th 4.750" inch range with stroke around 5.750"!!!



...and if that engine looks too lonley, I'm sure the Dragster list a few you could drop it in!!!!...not in exchange for College though!
I don't what I was thinkin of then, aparlently I haven't seen this class then because I think I would remember 800cid :D That is huge! All that makes perfect sense, I see now.


Ahh, good old college, only 2 1/2 more years before it saps alll my money dry, oh well thats how it goes.
 
Originally posted by Windsor377@Feb 22 2003, 04:55 PM

Not sure, what data aquisition do you use? Anyhow it looks like something droped off a little early...pick up?
Last year he had one of those pans that have the ball bearing type deals to keep the sloshing down, well, there must havve been too many because not only did it keep the sloshing down but when he took off it kept the oil from getting to the sumps. problem fixed now.
 
Originally posted by Windsor377@Feb 22 2003, 05:00 PM

LOL!!! Ti can be your friend...if you treat it right...don't overheat or let it gall.
Ti :wub: Will have to save this discussion for future topics, oh yeah, definently.
 
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