248 high-perf pistons!

A

alleycat

Active Member
After beating on Egge for about 6 months, I finaly got them to step up to the plate and make me some pistons! Well, not quite. They don't want to machine them (too hard to make up a new program for the machining center, been there, not!) and they don't want to make just 8. So, I'm going to order up at least 50 pistons, as cast. And machine them myself. Rather a bit of a time consuming job, but thats hot rodding! Since I'll be doing it myself, I'm going to come up with the most cutting edge piston that has ever gone into a str8. They will be a near hyperutectic alloy, 3-ring 1/16, 1/16, 5/32, moly ring pac, cut down skirt, off-set pin, weigh about 400 g, and CR of 6.5 (stock), 7.5, or 8.5, without cutting the head. And anything else that I think of in the mean time, they'll get. Should be worth about 5 hp a hole. Since I'll be only using 8 for my engine, I'll have some spares. If any of you guys are doing or contemplating doing a serious str8 build, I'll be able to make up a few sets. I will probably get the blanks about the end of august. I've no real idea of how long the first set will take to do but once they "smell right" probably can make 'em for other engines sometime next year. These things will be killer! alleycat
 
Sweeeeet Alleycat!

By the way, I still haven't touched those heads or had them on the flow bench yet. I know, I suck!!!
 
"as-cast" pistons should'nt cost that much more than the alloy their made from on a quantity basis. The real cost is the machine work " cam grinding, precision pin bore, ring grooves. A store bought piston vice will add to the price. good luck
 
Riiiiight! Tooling up to machine these pistons is likely to be just as big a job as machining the pistons alone! All the fixturing will have to be exclusive to these pistons. I have no idea as to how many hours I'll have into just one piston. However, the piston is a rather important part of building a serious engine, and there is hp to be gained. I don't think I'll have to cam grind the pistons as I have quite a collection of used pistons of several makes, and they all have too much cam in them. The egge piston is a 15%-ish silica alloy which cuts the expansion rate even more, so I may be able to turn it "round" and be fine. Substantialy reducing machining "trickeyness". Even at .140 over, with a extra .001 or so clearance, it should be ok. alleycat

P.S. come on "J"!, lets rock! The suspence is killin me!
 
I know of some people that have gotten Keith Black to do custom small "private label" runs in the quantities you have mentioned, for a few extra bucks per piston, might save you the trouble of having to tool up and finish them yourself. I would think that with the economy the way it is, Egge would jump to have the opportunity to accomodate you....
 
I will see if my friend will give me more details about possible contacts at KB or even other companies he spoke to regarding this. He was trying to get enough orders(50 pieces) for the 292 Chevy guys on Inliners , and was trying to be the middle man. It sounded promising anway, and most people think they offer a pretty good quality hypereutectic piston also. I'll check back and post any info about it.
 
When I started this piston hunt, about 5 years ago, I started by calling the usual buick piston suppliers just to find out what the pistons were made out of, who made them, where?, etc. Egge was the only one that actually knew, and would tell me. A really strong, totaly stock piston in a totaly stock engine might make a person feel good but it's kinda redundant, since a 248/263 only cranks out about 80-90 hp. The piston really needed a fairly serious redesign along with the strenth. A hyperutectec would be great, but near or say, 15% is just fine. Egge had this but did'ent want to do a totaly new piston. I started calling, e-mailing, all the other piston makers. Most were not even intrested. This was some time befor "it's not a recession", mind you. Flat tops, no sweat! Yah, if you want about 4 to 1 comp. Ross could make a forged domed and it would weigh about 600 gm and it's out of 2024. Jahns could cast something, really heavy, alloy? I would'a REALLY liked a KB hypereutectec but the tooling....for 8 pistons...nope. Back to Egge. Nice hollow casting, right material, light of weight, can be made lighter but the rings... OK, can the rings be changed, I can live with and reconfiggure the piston, welllll...do you know how hard it is to reprogram the CNC?.....I'm getting annoyed.....It is diffinatly, now, "not a recession", you would think these guys would be inclined to at least peek out of the box. Jeez, if it ain't a chevy!!!...OK!.....Just cast em!! How many does it take!!! If it has to be the hard way...... alleycat
 
Maybe we could ALL call and bitch about it too them. Clog there phone lines with unhappy straight 8'ers! Power to the people!!!!!
:D
 
straight 8

Here's the pistons we run in the 320. They came from CP Pistons. Took three companies and six months before finally CP comitted to make these for us. We bought 10, and they started with a small foreign engine blank that they could do easier than starting from scratch. The other two pistons in the picture are a stock one, and one from Egge that was made on a design that Buick used in NASCAR in 1951. They were stocking them, but not sure if they still do. We sent it to CP as a template for what we wanted.
Doug
 
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Alleycat I have read this blog all 600+ entries many times and I thought somewhere in here I remember you having a 263 in your shop. since the 263 has more modern main bearing and piston design I'm wondering why you would chose to invest in a 248 rebuild. Forgot to mention 5/8 shorter crankcase and factory offset piston pins on the 263.
 
while I was hunting and pecking out my reply Buick Guy slipped in the picture of those 3 pistons. the one on the right hand side looks like it could be used on stock rods but the one in the middle looks like the compression height would require longer rods
 
Well...I was'ent going to redo the 248. After blowin it up about 3 times, the 4th rebuild actually was working pretty well. But the car...had gotton so bad, nice engine or not , ya just did'ent want to drive it. So, I did a fairly serious body redo, not a frame off mind you, and I was ready to put the engine back in and do the interior. Engine came back from the sandblaster and sand had got inside, pulled the pan and there's a yellow jacket nest in there!!!! Well, now it's a completely down....I had in the mean time come up with a bunch of new ideas, 248 is now a very good candidate for them. The 248 is also identical to the 320, just smaller, so everything that I do to it totaly works on the 320. I do have a 263 that is done except for the top end, and I was and still am unsure as to what is the best way to port the head. The dual carb intake is not up to speed for this engine. I was going to section a 320 dual intake to fit the smaller head, but now I'm considering casting a whole new intake. The 263 is also intended for a different car, so if I used it in my 50 I'd still have to build another engine.

6 months huh....got right on it, did'ent they....I looked at everything Egge had, nothing even like it. They do have the 38-ish pent-roof piston but I never really liked that style, edges and angles hurt power. A dome does the same thing and won't hurt power, up to a point.....A dish in the piston has shown to produce the best power, with a flat top piston and verry small combustion chamber. Which the str8 does not have. Buick actually came up with a clever design in the last style piston used, sort of a dish tilted on the side of a dome, and all the piston makers hate it. I don't know what the best shape may be...

Dave! I want to see those pistons! I have my crank up the road at Castillo's and when it comes back it'll be 25 lbs lighter, so heavy pistons are out, but I still want to see em!

Maddog has NO clue as to where their parts come from! But, on a stock rebuild, a full flow oil filter,oil with zinc in it (none of this EPA crap) it'll live forever. It's not a bad deal, considering what some guys I have talked to, have payed to rebuild their str8's, boy, did they get it socked to em! Wow. alleycat
 
straight 8

Charley,
Good eye. The pistons that CP made for us are on 9" c/c rods. The Buick uses a rod that is 1 1/2 thick and none of the rod people want to order stock that is specific to that engine, so we had to use Chevy rod thickness necessitating welding up the crank throws for side clearance. "VERY" expensive. all in all, it made a nice bottom end. Hope it all stays together next week on the Salt. If anyone wants daily updates from the Salt, check out Salt Cat Racing on Facebook after next Wednesday each evening as we will try to keep everybody posted.
 
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those are nice rods. did you finish the crank to BB chevy 2.200 big end dia.? Looks like you have a pin in the rod cap and the notchs to keep the bearing from rotating. I bet a lot of the cost on the crank was the time required to keep it straight after all the welding. I could only pull up one of the pictures, the one with the 7 rods on the bench.
 
straight 8

The Big end was turned to 2.0 small block dia. The width was dictated by the best available material short of ordering 1 1/2 inch wide stock to make special width rods. The small end was easy as the pistons could be made to fit the rods. The guy in Great Falls, Mt. that did the crank for us Greg Takke, runs an alcohol dragster and a full machine shop. Does excellant work. The crank had to be welded up to prevent a massive oil loss out of the sides of the bearings as the rods were more than a 1/4 inch away frrom the crank cheeks. He said that he had never seen a crank "crawl" around like that 41" long chunk of iron. When he was done, it was dead straight. We'll know more in about 8 days. We're having fun now. We hope to have daily updates on Facebook on the Salt Cat Racing page. Some video on there now. Anybody interested, check it out. Doug
 
Back on #12 Charley mentioned that the 263 has offset piston pins. I knew that, but have never checked what it actually is. None of my Buick service manuals mention what it is either. I assumed it was about .030-.o40 which is a fairly common offset. Assume nothing. Since I will be offsetting the pins in my yet to arrive 248 pistons, I could just copy the 263 offset into my pistons. I have 2 sets of 263 pistons in the shop, so I pull em down and check. Holy Cow!!! About .150 offset!!! I've never seen this much offset. My understanding of pin offset is that it spreads the load at TDC over a greater number of degrees rather than all the load at exactly TDC and more importantly delays max piston speed a few degrees allowing the intake valve to be more open relative to piston speed. Pin offset is something I've not given a lot of thought to...Any thoughts on this? alleycat
 
Back in the day when a lot of the guys that ran 440 Chryslers in Stock Eliminator and Super Stock used to swear by installing their pistons on the rods backwards to flip the offset in the other direction, claiming it freed up HP. If you have ever seen some BME Super Stock fly weight pistons from Patterson, you will notice that also they have moved the offset in the opposite direction(toward the major thrust side) relative to the piston centerline. In recent years, I have worked very closely with a current Comp racer who also has JE move the offset on his pistons to mimic the offset of the Super Stockers, and has seen actual dyno #'s verifing it does have some gains. It actually does change the rod angle and velocities as it approaches and exits past TDC. So there is something to the pin offset practice and a lot of racers are doing it, it just isn't widely broadcast....
 
Pin offsetting as practiced by the factory is solely for eliminating piston slap at TDC and making a quieter running engine. I would think that if there was real power in reverse offsetting the pin you would see "off the shelf " performance pistons come with this feature. Most have the pins straight up. If you have custom slugs made you can have them easily move the pin anywhere you want. I don't think that there are big gains to be had but the only down side I can see is a little more noise.
 
Agreed, its one of those tricks you pull out of your hat when you are reaching the end of things to get every last HP out of an engine combo. On my friends 353 SBC that made 968 HP,it was good for 15 HP....1.5% gain. But when your in the hunt for points, thats just what you do to find all the HP you can. It didn't cost extra $$$'s to have them offset them, so you basically got 15 HP for free..... A race only mod, you wouldn't do it to a daily driver.
 
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