Alright everyone i know that someone more qualified than myself should be doing this. But i want to build this using my hands only. so i might have a few questions along the way and I hope that you guys may be able to help. first things first i bought some plasma rings for Jegs and i bought them .035 over sized to file them to fit. the question that i have is """when i file the what should the compressed gap be and how square does the gap need to be.""" i bought the "filer" but i can see where it whould be though to hold them straight and make the gap very square. thanks for all the help in advance.

theo

 

Too many things to consider.

 

can u give me some examples of things to consider?
the pistons that i have chosen will give me approx 10.3 - 1 compression. it is a chev 350 bored .030 over. i am a machinist and have quite a bit of knowledge of diiferent things that are involved with the building of engines.

 

Getting them as square as you practically can is a good idea, since it prevents any points from being developed at the ring ends. As the rings slide along the cylinder with the piston, the square ends will not mark the walls, whereas an angled or pointed end may score the wall, and worse, break off. They don't have to be surgically perfect, but as close to 90° as you can get them. If they are within 2-3°, they should be fine.

I'm not certain I understand what you are asking about the end gap while filing, but the final end gaps should be as close to the gaps recommended by the piston manufacturer as possible.

Take your time. You don't have to get all the material off in one shot. Be careful not to spring or twist the rings too much. By the time you are finished, someone more qualified (you) will have done the job. Then you won't have to ask next time.

 

thanks Vader,
nest time i need a little boost in the EGO i will definetely get a hold of you! ha ha ha ha

seriously thank you very much for the info.

theo

 

First off, Ive never heard of a .035 oversize file fit. I believe you are talking about the bore size maybe? Ring makers generally offer.005 oversize rings for filing.

Things to consider are: Intended usage of engine, type of fuel,ring type, street, racing, N/A or power adder. One thing, just as an example, if you ever plan on using nitrous, you would have to go on the "loose" side of the recommendations, due to the fact, when the cylinder pressure rises, and the metal expands, your rings will "butt" together and break!

Lots of things to consider before you go filing. No one can answer your question except for the ring maker. He will have the best answers to your many questions.

 

BRUTAL
the biggest thing that i was wondering about was how square they had to be as the manufacturer says that the recommended ring gap is .016 to .018 gap.

thanks

 

Oh, I saw compressed gap in the thread.

 

Final mechanical compression ratio is less of an issue than whether you plan to boost with a turbo, blower, run specialty fuels, or add nitrous. These type installations usually warrant a larger end gap. Also, vehicles used for heavy duty use, such as towing or racing, may require a bit more gap. Short of that, stick with the manufacturer's recommended end gaps in each of the ring positions. Common end gaps for cast pistons of that bore are 0.010-0.020" for the top ring, and 0.010-0.025" for the second ring. However, depending on the pistons you are using and the type of use the engine will get, you may want to alter that. You can find some good information here: http://www.kb-silvolite.com/clearance_pop.php

Of course, the specifications provided by the piston manufacturere are the best starting point. If the specs were not included with the pistons, contact the manufacturere for the information.

 

Never mind. Brutal already covered most of that.

 

O.K. Vader
help me out on this. the web site that you gave me is saying that if i want to run nitrous on my 350 that has bored out .030, hyper pistons, the gaps should be .032
4.030 x .008 = .03224
CORRECT?

 

All my engines get file fit rings. I clamp a file in the vise then move the ring over the file to file it. As mentioned above, it should be as square as possible. Do a little bit at a time then install in into a cylinder and check the gap with a feeler gauge. If the face isn't square, you'll really see it then it's in the cylinder.

Gap depends on bore size and engine use. I use Speed Pro rings. For a NA engine, both rings is .005 - .0055" per inch of bore.

For a .030" over 350's 4" bore, that would make it 0.020 - 0.022" gap. For NOS use, .006" per inch of bore is recommended. Supercharger and turbos need even more.

New rings come with instructions as per how much gap is recommended. Too much gap and you get excessive blowby. Too little and the ends will butt up against each other when the rings heat up.

 

i use a ring filer, never checked but it never seemed to me that it's hard to put the ring in the filer square and then keep it square as i grind it down. as for keeping it square in the bore i made a squaring tool from a piece of plastic turned in a lathe. i use to use a tri square to get the ring squared up i nthe bore but it took a lot of time.

 

ok everyone i called K-B today and the tech there said that since i'm looking at putting nitro on it later that i should file the rings for it now as it wouldn't hurt anything. since i'm looking at nitro i should gap the top rings at a minimum of .032 and that if i wanted that i could go all the way up to .040 and it wouldn't hurt anything. the middle ring should be .016-.018. But now i ran into a new problem. when i got out to my buddies garage today i found that someone was lokking at the rings today and mixed them all up. im not sure if it matters but i dont know which are which. obviously i know the oil rings but the others i do not know. they are color coded but dont know which are which from there either. if someone could help me out with the colors or what is different about the two i would appreciate that very much.

thanks,
theo

 

i think if you have to ask about ring gaps you need to leave nitro out of the engine, if in fact you are really going to run it, or can afford to run it. do you know how much it cost? something like 40 dollars a gallon. as for your rings yes it matters there is a top ring and a second ring that are not interchangable. you didn't notice how the maker marks them to location? they didn't do that just becasue they wanted to.

 

so much for trying to get some help. i didn't say that i was going to put nitrous on it TOMORROW. and i think i could probably afford. i didn't realize this was a site for bashing people. this is the first motor that i am building on my own and thought that i could get a little help here. everyone up till now has been very helpful. sorry for asking questions on a forum site.

oh and by the way like i said in my post yes i noticed they were seperated but im not the one that took them out of the box and mixed them up. SORRY

 

You have your 1st compression ring, 2nd compression ring, oil ring (zig zagger) and two small spacers for the oil ring. The gaps cannot be on each other.

Front of engine
............^
............|
..........___
......../......\
......B|.......|A D
..... C \___/


B= 2nd compression ring gap
C = oil ring gap
A = First compression ring
D = Oil ring spacers

That is the correct way to put the gaps as far as my LT1, imagine the SBC's are the same.

Crappy I know

 

....

 

Thanks Pasky,
glad to know that i'm not too stupid for some advice and knowledge from you.

thanks for the info.
theo

 

sure we bash dumbasses all the time here. you never said anything about nitrous you said nitro as in nitromethane, big differance, at least to people who know. did you come here looking for advice or someone to agree with you. you're a fool thinking you can build an engine one way and add nitro, or nitrous, on later and optomize preformance. since you seem to know everything i won't bother trying to help you with the granade you're trying to halfass together

 

 

So, to keep this on track, you are considering using nitrous (NOS, NOX, NO², or whatever else you might want to call it), but not nitromethane, correct? Ede is right, there is a big difference, and I can see where he would be taken aback by that one. That makes for a big difference in complete engine design.

Whatever you are going to run, did you sort out the rings yet? There are often small dots or circles on the rings, identifying their position (top or second) and orientation (up or down). The ring packaging should have the code on an inner flap of the envelope or box.

 

No one tried to bash you. If you look back at what you wrote, you might want to be a little more clear on what you are saying. People can only go on what you type in the thread. No one here said anything that I would take as insulting.

 

Sorry Ede for taking that the wrong way and sorry for not being so clear in what i was trying to say. how about i list all the parts that i currently have and if you guys see anything wrong with the choices that i have made you could let me know

1980 Chev 350 Block
-bored .030 over
-tanked
Holley 4 barrell
- list #6210-3
Comp Cam 268 Extreme Energy
Edelbrock Performer RPM Alum Heads
Edelbrock Performer RPM spreadbore Intake
Silv-O-Lite Hyper Pistons
Speed Pro Plasma Moly Rings

Sorry for all the confusion and again sorry for taking affence to the comments made earlier i did not know of nitromethane to be used in cars.

thanks again,
theo

 

Out of curiousity here and not to take away from the thread, what exactly do you look at as far as strengthening an engine for nitro?

 

So you're going to end up with a 355, carbed, with better heads and a decent cam. What rods and crank are you planning to use?

The 355 with a decent cam alone can stretch the limits of stock rods and cast cranks. I had a 355 in a '50 truck 9at Iola once) that made 423HP at the crank, and it probably should have had at least a nodular crank. I did balance it well, but it was at the limit. Adding any kind of boost or nitrous would have been a disaster waiting to happen.

Also, what valve srings are going onto the heads?