Pistons & Rings for good oil control.

bhaugeberg

Hello, nice to meet you all.

I am looking for recommendations for pistons and rings for my big-block build. My build is going to be a 99% street type of build based on a 427 that will go into my 67 Camaro. I figure that I will probably take a few runs down the strip in it but that will definitely not be the focus of this engine build. I have looked at hypereutectic cast pistons and for the 427, the choices are a little limited but there are a few that would work.

I am wondering if there is a manufacturer of forged pistons that is worth looking at for a build such as this. There are more choices in forged pistons and some are lighter weight than a hyper cast piston. I am a little worried that the oil control will not be as good as it has been for me when I have used KB or Sealed Power hypereutetic cast pistons with file fit rings from Sealed Power. I like it when you can drive 3000 miles and only lose 1/2 a quart, like my daily driver does. I am not necessarily expecting that from this engine, but I do not want oil consumption that is a quart in 200 miles like the last engine I had with forged pistons. That engine had only about 20,000 miles on it when it got that bad. I do believe I know what caused it and can prevent that from happening in the future.

What kind of recommendations can you all give me? I will likely be using a Dart block with the bore somewhere between 4.25" and 4.375". Thanks

squeeezer · Posted: Fri Jan 28, 2011 9:40 am Post subject:

mahle 4032 power pack

clay · Posted: Fri Jan 28, 2011 8:36 pm Post subject:

I have used a set of SRP's and they appear to be a well made piston. I can't really give you a good oil comsumption opinion as most of the time it was running it was getting the crap beat out of it - still good though. Torque plate hone and a good set of rings goes a long way I believe. SRP does have a pretty large selection and I would think they would have something you can use. I believe they are a 4032 alloy piston also - little tighter bore clearance I think but not quite as tough as a 2618 alloy. What cubic inch are you looking to wind up with as far as bore and stroke? Welcome to Smokemup. Clay

af2 · Posted: Fri Jan 28, 2011 8:45 pm Post subject:

bhaugeberg · Posted: Sat Jan 29, 2011 5:54 am Post subject:

At this point, I am thinking that it will be a 447. I have found 2 ways to do that. Both involve a 4.350" piston and 3.76" stroke. One way uses a KB hyper piston with a 6.135" rod, the other way is either a 6.635" rod or 6.660" rod with a little decking and/or a thick head gasket. I like the long rod idea because it is different and the piston is a 1.270" compression height, there seems to be more choices of pistons in that height. Not only that, with the long rod the piston/rod combination is about 130g lighter. Which is good for a street motor, it will accelerate quicker that way. With the long rod, I can use a KB hyper or Mahle makes a nice piston that will work as well. Both have a 17cc-to-18cc dome, which will make for about 10.25:1 or so with a bit of a flat mill to the AFR 290 heads I am thinking of using.

With good port fuel injection I am thinking this will produce well over 500hp and be reasonably efficient, when I am not on the gas, especially compared to a larger CID, carburated engine. Do I sound like I am on the right track?

clay · Posted: Sat Jan 29, 2011 10:49 am Post subject:

Larger bore, shorter stroke, lighter piston - I love it all. Good head selection too. I think you will be very happy with the direction you are going. What type of valvetrain are you looking at? If it's hydraulic roller you really need to do some research because you are building a combo that can stand some decent rpm's. Keep us posted - sounds like a neat build. Clay

bhaugeberg · Posted: Sat Jan 29, 2011 3:36 pm Post subject:

I have looked into camshaft options, including hydraulic rollers. Right now I am leaning toward a moderate duration solid roller using Comp Cams XE street roller lobes. I have run these cams before and with the right valvetrain equipment they hold the lash pretty well. The duration will probably be a single pattern in the 230ish range @ 50 with a wider than typical LSA. I have been studying the Gen III GM 7.0 LS motor and realized that the AFR heads flow as well if not better than those heads. With the right cam, I should be able to match or better that performance.

I was actually planning to use an LS motor but decided that itch could wait until the motor in my '98 Camaro needs rebuilding. I had no other opportunity on the horizon to do a big-block other than my '67 Camaro, so I changed plans. I have build about a half dozen small-blocks over the years and am tired of those for now.

Bryan

Big Dave · Posted: Mon Jan 31, 2011 1:19 am Post subject:

A forged piston doesn't promote oil consumption. The ring tension on the oil ring pack is responsible for most oil burners on the road today as every one wants to run a low tension ring package to cut down parasitic loses. I like a CP or JE piston and Mahle makes an excellent piston as well and they come coated for the price of an uncoated JE piston.

Big Dave

af2 · Posted: Mon Jan 31, 2011 5:52 pm Post subject:

Yep Dave
X20000000 on that post!

bhaugeberg · Posted: Mon Jan 31, 2011 6:14 pm Post subject:

Thanks for the info guys. The engine with the forged pistons that I had the high oil consumption had a couple of problems. The first problem was, as was pointed out, I used a low tension oil ring. The second problem was that I used a Victor Jr. intake on the street. The distillation curve with gasoline these days ends at about 450F on street gas, so if you drive around on the street with an unheated manifold you get a lot of unvaporized fuel going into the chamber. I believe that the fuel wash greatly contributed to the high oil consumption. You could see where the fuel hit the piston as it removed the carbon quite nicely. This was probably why the oil control was OK when the engine was new, but after 20,000 miles or so, it was at 200 miles per quart. Not only that, most of the cylinders had enough wear that the clearance was 5 or 5.5 thou on all the cylinders. If I remember right, the clearance started out at about 4 thou on all the holes. I look at it now as an expensive learning experience. That motor was one of my first builds, it was 20 years ago. I like to believe that I have learned a lot since then.

Bryan

af2 · Posted: Mon Jan 31, 2011 11:37 pm Post subject:

[quote="bhaugeberg") The first problem was, as was pointed out, I used a low tension oil ring. The second problem was that I used a Victor Jr. intake on the street. The distillation curve with gasoline these days ends at about 450F on street gas, so if you drive around on the street with an unheated manifold you get a lot of unvaporized fuel going into the chamber. I believe that the fuel wash greatly contributed to the high oil consumption.

Bryan[/quote]

Don't get too involved in that discussion!
Unless you were blubbery rich/fat that reason is mute.