To Alleycat

Jyrki

Jyrki

Team Member
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Alleycat, I am curious as what kind of mods have you done on the cranks in your hi-perf 320 engines? How does the standard crank hold up with high revs? I would also like you to unveil the secrets of the rods you have used! The rod length is so extreme that I haven't found any contemporary performance rods that could be adopted. And what about pistons - I bet you have had some custom pistons made just for you, right?
 
Ha! Kinda wondering when someone was going to ask some serious questions. I've built only 1 320, my 248 a number of times and currently favor the 263 as the best of the bunch. The 320 and 248 are basicly the same engine, just bigger or smaller depending on your viewpoint. The 263 is a totaly moderen engine and as such has far and away more modification potential, the things that can be done to these is unbeliveable. The cranks are forged steel, a very good unit. Tape up the journals, get out your 41/2" and grind off all the forging flash, index notches and general junk hung on the unit, don't take off the sharp edge around the journals where the crank arm transitions from the journal, this edge help fling oil. Get out your die grinder, various flap wheels and polish all rough surfaces to a 320 grit or so. At this point it is pretty darn good, however, if you want that last yard, take it to a plating outfit and have it buffed. Lastly, send it out to a crank grinder with the newest grinder and a guy that knows what he's doing. It's done. The rods are forged and not bad units,the bolts are the only thing that could use a update, as metals technology is vastly improved. However, rods and bolts only fail in tension, not compression, and tension comes with lots of rpm's. Something that we'll never get with str8's. The rod can be beam polished, sharp edges around the bolt head and nut flats smoothed and polished and then shot peened. You MUST be VERY carefull about who does the shot peening as some of these guys can DESTROY your rods, check and double check who you give your rods to. Pistons. Absolutly, hands down the BIGGEST problem with str8's. These engines need a moderen hyperutectic piston design badly. We're probably not going to get it. As such, I've had to be very creative. The buick piston is not a bad design. I thought that it was' ent, piston design of the '60's influenced me. Turns out that the buick design is probably better than even the boys at buick knew. That said, the alloy is 2024, hard anodized and very long, not good. The replacements are not even that good. If you have oversize genuine buick pistons its the best short of customs. I've even put harley davidson 74" in my 263, in order to address the problem. Not the correct dome but it's experimental. So what to do? Stock pistons, first, aftermarket, second. In all cases, polish the top, leaving no imperfections, buff it till it looks like chrome. Moly rings are nice, if you can find 'em. Just shy of a mirror finish on the walls, none of this generic 280 grit hone stuff the rebuilders want to put on, "it'll never seat". Bull. What it'll do is eat the rings and walls up. Been there done that. Lastly, str8's will never turn over 4100 rpm, even with my best all out head. And, you don't want to go more, at this point inertial problems are going to get out of hand, fast. You'll be throwing engine parts into the back of your pickup and towing it home.... This should give ya' something to think about. alleycat.
 
Well, finally past the X-mas stuff and back to business.
So, Alleycat, you are saying that provided you keep the revs below 4 grand, the standard crank and rods will survive with the traditional mods you listed. Glad to hear. As you pointed out, the STR-8 doesn't even rev much past 4000 rpm. I can verify my 320 seems to lose power rapidly past 3600 rpm. Speaking of rod bolts, is there there a p/n from ARP or some other that would be a direct fit?

It's been a while since I last vsited the HAMB forum. I browsed thru the exhaustive information that Chub Chub pointed out (thanks a lot!), and it seems Ross now makes a performance piston, but I quess only for the 263?
I used replacement 030 pistons from Egge. They came with a Grant ring set, which makes use of one modern oil ring and one STR-8 type. I decided to discard the STR-8 type and use the modern type only, so I have nothing on the lower oil ring groove. So far so good. I also filled some of the dish, and coated the crown with a cermet coating (thermal barrier). This was done to raise compression and efficiency.

Okay, Alleycat, now we are getting into more exciting topics. What mods have you performed on the heads - chambers, ports, valves, springs, rockers? Again my main interest is in the large engine, but please shed your light on all engine sizes. I'm all ears, and so are all the others!
 
didn't ross make them awhile ago? i remember calling them for my former 263 a few years ago........this thread is getting really good keep the great info comming.

viva la hamb :)
 
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Well...in respect to the 320, you WANT to keep it under 4000. In my blurb above I was basic and brief, I could write pages and pages about this stuff... but the 320 is longer and taller and bigger. Mass in motion tends to remain in motion. The dynamics in that engine get outta hand fast, in the 248 and 263, which are more compact, it can be controled better. There is some supprisingly clever enginering in these engines and understanding whats really going on is key to the whole deal. Don't lay awake at night 'cause ya don't have a 4140 crank, work with whats there. Its good steel in there. All the old hot rodding tricks work, I use 'em because these engines respond to it. Of all the engines I've built the buick str8's are the most responsive. Virtually everything, you can feel in the seat of your pants. Forget "chevy think". So, all the stuff I relate here applies to all 3 engines, and its not "feel good" modifications. Gettin the power is not about doing 1 thing 100%, its about doing 100 things 1% and that 1%, 100%. These babys respond. Now, the reason your 320 flattens out at 3600 or so, is the top end. It just wont flow. The first thing you should do is get a buick duel carb set up. Every str8 should have 'em. The single carb runs the center rich and the ends lean, and the exhaust won't clear the cylinder. I have pulled more destroyed pistons out of str8's because of this than I can count.

A little more on pistons. I droped the 4th ring long ago and it works fine, but these engines badly need moderen pistons, ring placement and rings. The boys on the HAMB site are in the hunt but if the piston that fits their engine fits others...but 320's and 248's, no. Ive looked into custom pistons, the actual piston is not such a problem, the dome configuration is. Flat top pistons are best for flame travel but the chamber is WAY to big, and we have to live with it. Plus the little detail that if one of those pistons gets hurt, another must be made. This lead me to harley pistons. Everything is made for harleys. This piston gives everything ya want. Off the shelf. Plus 310 inches after its in there. But it only works on the 263. The drawback? Gotta make rods. The pin is higher and so the shorter 263 must be lenthened. I had access to a wire feed EDM, so I cut blanks out of 6061 aluminum and made my own. The harley piston has a hemi type dome on it, clears everything and gives 9:1 comp. Is it perfect? Probably not. But this baby makes power. I've also tried ceramic coating piston tops and it works when its fresh but as it gets covered up by carbon the effect diminishes. Plus the engine has messy combustion and a mirror polish everywhere seems to work the best. So, I did'nt do it in this engine, but I did teflon coat pistons and bearings, str8's have a lot of internal drag, it helps.

Ahhh...the head. What have I not done to the head? Morphidite thing. Bunch of plumbers cobbled this thing togather during break, I'm sure. That said, it can be made to work. Don't sweat that its siamesed, the inactive port acts as a plenum. Its all the square corners. The exhaust valve is ok. Intake needs to be bigger, I have a bolt in pt # for it. Gives 75% or so intake/exhaust ratio. I made my own valve guides, cut them on the top for PC teflon spring clamp seals, on the exhaust because the exhaust blows UP! the guide. Tried it in the intake, did'nt work so well, still got a lot of coke build up on back side. Flow loss! No good. So, I'm now trying umbrella type, just deflect it. Blunt conic on end of guide in port. 4 angle valve job, back cut valves, swirl polished. Highly polished exhaust. Drop the port floor about 100 thou, stoping about 1/2" carb side of the left/right corners at the end of port. About 7/8R on the corners, nicly rounded, and ramped up on the floor to giv a short side radius. Raise the roof about 100 thou all the way into the plenum, creating a nice rounded bowl shape at each end. Do not cut straight down to the seat, leave a rounded venturi. Thats the basics. Takes a few hours to do. However, this head will not work for spit with a stock intake/exhaust system. Factory duels, modified, at the minumn. I'm working on dual quads and stainless steel header, should really rock. I think this is enough for now. alleycat
 
Alleycat, even if you are only touching the subject, each reply of yours requires some time to digest! Let's try to keep this thread alive and not get choked by taking too big of a chunk at a time...

When I was working on my 320 head, it was obvious why this behemoth doesn't make power - it cannot breathe! The BB Chevy exhaust valve was a direct fit for the intake valve, even the stem height and diameter being close enough. I used Manley Race Flow 1.88" diameter, slightly larger than original, swirl polish, necked-down stem, everything. I left the OE exhaust valve in place, only did the back-cut on it. I was able to remove LOTS of material from the bowls and guides, but I didn't touch the ports because at the time I was working on it, there was nobody who could have verified how thick the walls are and how to shape them. I did make an intake for dual 2-barrels, all ports equal-length, and headers. The torque is awesome. A friend with a '49 Roadie said he wouldn't have swapped an SBC, had he known how much potential lies there.

Now, your description of the port job is stretching the limits of my understanding of English. I understand avoiding removing excessive material where the port floor makes its turn to the valve, as the radius is very limited as is. But at the other end, are you saying that you made the ports slightly rectangular, leaving a short section of it round, so it still mates with a round intake manifold? Well, a picture would explain it.

I would like to stick with the head tricks for a few posts more, before jumping into other parts. Thanks and keep the info coming
 
For those who havent's visited my site, I'm trying to post a picture of the intake here. Let's see how it works.
 

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And here's a picture showing the valves, the exhaust being the original and intake being a Manley stainless Race Flo unit. As a bonus, you get rid of that 5cc cavity on the combustion side of the OE intake valve, raising the compression a bit.
 
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`Jyrki!!! Wow!!! You diffinatly are in the hunt! The photos are great. Photos are at this point beyond me. Describing porting without photos is hard. I'm very suprised that a BB chev valve works, don't know why I did'nt use it as I have several BB chev cars, and have worked over the heads on them as well. anyhow, as you look at the port from the intake side my port looks like a BB chev oval port heads intake, just smaller. The reason for this is that as air flow moves through the port it moves bottom to top as the valve moves up and down, with the short turn radius acting as a pivot point. Now, fortunatly, the port wall is thicker on the bottom and top,about .250-.280, so a .100 off the top&bottom is cool, but the sides are down to .210, going wider just kills velocity, which we want to keep,so leave the sides as is. The problem we'er trying to fix is that the port approches the valve at 90 degrees,realy hard to fix.

My first set of headers looked very much like yours, and I found that they are with out a doubt one of the biggest power gains on these engines. However, it means a unheated intake, which made my engine REALLY cranky and hard to live with. So, I went back to the factory duals which I ported out to match the oval ports. I have found that a 320 dual intake can be cut down and welded, giving a larger internal volume. this might work better yet. Enough for now. alleycat
 
rpm

alleycat,i read with relish your talk on the straight eights.when you say 4100 rpm do you mean you shouldnt turn them past that point or they are incapable of it?i think in the lower gears they will turn around 5000 rpm if you just stand on it.and you are right this would soon tear them up.
 
Alley cat, You are digging into some territory that hasn't been explored in years. I am glad to see that your 263 is coming alive.

I have a question for you. I have a 263 in my 53. I am running an Edmunds dual intake with two holley 94's. I am still using the stock single exhaust manifold so I am not getting the best benefit from running the dual intake. I recently aquired a stock dual intake from a 41 buick. It has two Carter carbs on it, using compound carberation. Front is the primary, back is the secondary. Would I benefit running the carter carbs or running the matched Holley 94's? Which carbs are you currently running. I plan on using the Edmunds intake, it has the plumbing for running the heater line through it to keep it warm.


Fryguy
 
Never in my wildest dreams did I think that anybody would be intrested in the nut-case things that I've done with my buick...Anyhow, this rpm thing can get very involved very quickly, leading to a Lot of print...but I'll try. Will a str8 go 5 grand? Bone stock? Not a hope. Any engine, given a unlimited airflow potential, put a brick on it, will rev to destruction. Its the destruction aspect we'd like to avoid. How do we do this? Engine redesign or parts enhansement through sheer strengh of materials. The SBC boys have shown with out a doubt that given unlimited r&d time and $$$$$ any given engine can be pushed way beyond its design parameters. Where does that leave us? Jyrki's engine is a great example of what can be done reasonably, and he's in Finland! Yet, it starts to go "flat" at 3600. My 248's and 263's built in a same maner, would go about 3800. With my very latest head on a 263, I got about 4100. Not much of a gain. Wats goin' on? I did have the factory 2-2's on. Intake restriction? Jyrki dos'ent have that problem. Hmmmmm....Look at the bottom end, its huge. 320 rods weigh 2lb 2oz, and the size of the bearing journals!!! All the loads on the crank, friction, inertia,etc, increase with the square of speed. What I strongly suspect is that much beyond 38-900 the load on the crank is taking up more and more power just to drive it. The world famous "rock & hard spot". Aluminum rods take out a lot of weight, perpherial speed on the bearings due to their size can strip the babit off the shell and we don't have state of the art bearings....5000 rpm? Prehaps. Makes me nervous.
Fryguy, I've always used wcd carters, from 50 to about 54, as they were everywhere. Bigger on the v8's, I could mix & match, 4 bolt flange, bolts to about anything. Once set up, it's a "forget it" carb. I always ran them "straight up", as in, not progresive. The reason is, is that it's nearly impossiable to get even mixture distribution front to rear. The early carters will probably be to small, I'm runing biggest ones I could get. It likes it. I like the edmonds, but the internal volume is kinda screwy. Later. Alleycat
 
To be honest, the fact that anybody is still messing with these motors is awesome! I thought that I was one of the few that thinks a Buick should have a Buick, etc, and I'm 28! We should all be thankful that there are like-minded people still floating around to talk to about these old things! I've loved Buick Eights since I was a little kid!
 
rpm

what can be better than talking buick straight eights?im a young 71,and grew up teething on buicks.im still as avid as when i was 21.i have a 41 century and a 37 special.i drive the 41 every chance i get.in my literature is an british publication called (the motor).in it is buick road tests from 37 to 40 specials.they say the speeds given are timed.as an illustration a 38 special will do 58 to 59 mph in second by the clock.with a 28.5 tire height and 1.66 second and 4.4 axle the total ratio is 7304.this computes to 11.70+ mph for every 1000 rpm`s in second.58 mph divide 1170 = 4957 rpm.i dont condone this kind of use,and like alleycat says it is distructful.however with a .347 lift and the 1.35 to1 rrocker arm lift it would seem to underestimate the fabulous buick engines.i know they flatten out at 3800 rpm and up,but the dual carb 41 and 42 helped a lot.keep up the good work.
 
Okay Alleycat, I think I understood your description of the port job. One more thing. The 320 exhaust port doesn't actually have a decent valve pocket, as the port roof is more like a straight slope directly from the valve seat to the port, instead of a radius. Is there enough wall thickness to experiment some serious pocket porting on the exhaust side?

Speaking of engine being "cranky" without the heat riser, I can verify your experience! Although with the stock single carb manifold AND headers combination, it ran smoothly, but I only got experience from driving it in and out of the garage, so it doesn't count.

Now, how about the valvetrain. I have been wondering if the stock rocker arm ratio might be 1.5:1, but jerry burger suggests 1.35:1. Is it the same within all engine sizes? Alleycat, have you found any roller tip rockers that might interchange? And is there anything you can do to the pushrods? They look sturdy but they are soooo long! Now we are getting hot - alleycat - are you willing to unveil the secrets of your cam specs? Is there a company who could make a completely new cam instead of a regrind? I wouldn't want to send my cam overseas, you see. A couple of years back, I read the California Bill's manual on hopping up the Chevy and GMC sixes, and the book touches the Buick STR8 as well. It seems like Howards and Isky were making several grinds to the STR8, which were called "2/3 grind" and alike, which tells nothing to me (or to most others on this forum I'm sure). With the right specs, I could have my cam reground locally. Or I already did, but to stock specs, sans increasing the lift a bit, since they always have to decrease the base circle anyway. The #7 cam lobes were totally flattened out, probably due to an oiling problem. Anyway, this thread is like pouring some gasoline to the fire!
 
Face it jyrki, you've created a monster here. A regular frankenstein, with bolts.

I'm not sure of the rocker arm ratio, never measured it. Something I gotta do. As for roller tips, the sheer lenth of the arm eliminates anything made. I've thought about making some, but with a seat spring pressure of 52 to 76 lbs the effort would be for "coolness". Now the pushrods are another thing. They are 1024 steel, and when made were flat stock, rolled and welded lenthwise, then the ends pressed on. They flex and are soft as butter, or nearly. I've bent plenty, and found plenty bent in engines I took apart. So, I went nown to my favorite hot rod aircraft place and got some 4130 .375 tubing and made my own pushrods. That worked. Then I made some out of aluminum, tapering up thicker in the center. I think if I do it again I'll make a die and hydroform them. Lighter still. In any case this fixes the pushrod problem.

Camshafts. We have a little problem here. Once, long ago and far away, new cams were made. If any are still around, I've no idea where. So, I've thought about welding somthing up but the cam is way long, it could end up looking like a pretzel. I've thought about making a roller cam, it could fix a coupla things...I have seen more than a few flat cams, wrecked lifters, lifters not rotating....Why? Turns out that on a lot of engines, prehaps all, the cam does not line up with the lifter bores. Not good. Is it the cam? The lifter bores? Not sure. The only fix so far is to shove the cam as far back in the block as it takes to get the lobes off center to the rear, the lifters will then most likely, rotate. Cam&lifters are not cheep, ya want to check this. Then a spacer must be made for between the cam and gear, this can be .100-.150 thick, these lifters have a big base circle and sometimes it has to go way back. Cam grinds, hmmmm, problem here too...Compression. A cam only adds something like 10-15% to the power game, increased duration pushes the power curve higher in the rpm range. Due to the flow potential of the head, we don't have a power gain over 4000. The meat of the power curve is 2000-3000 or so. As soon as the duration gets "out of the window" we start to loose compression, by the valves being open too long at low rpm. With 7.5 comp stock, unless its been milled heavly, and even then, comp goes down fast, so does power. I think we're limited to about 215-220 duration. It may take a thoughtful cam grinder, but what we need is as much cam as possiable with little compression loss. I've not found it yet. What works on a sbc does'ent on a buick.

Exhaust porting. They are not bad. The guide suport is way to big. The walls are about .250 thick. Make the floor wider & flater, a "D" port, basicly Shape the guide boss by sliming it side to side, and front to rear by blunting the front and tapering the rear, kinda like a flat aircraft wing. Don't get really crazy here, as the exhaust can out flow the intake and about 75% of intake is what we're shooting for. Be careful of the end ports, you can get water in the upper corner if not careful, just round & smooth. With headers or factory duals its hard to improve.
 
Alleycat, you have definitely done your homework on the STR-8! I can believe someone making his own pushrods or even connection rods, but fabbing up a cam is just too much!
Your reasoning against increasing cam duration makes perfect sense to me. Even if we didn't count the lost compression, moving the power peak rpm past 4000 would be waste of effort. I agree, the majority of power is found by mitigating the flow restrictions - the head and the manifolds. But we COULD benefit from increasing the valve lift and/or the opening rate. This could be done by regrinding the cam or by increasing the rocker arm ratio.
Since you mentioned the valve spring pressures, I got the impression that you are using nearly stock spring pressures, am I correct? While using the BBC valves, I would encourage using BBC retainers, locks, and springs as well. I'm not sure, but I think even the stock BBC springs are rated higher that those of Buick.

Speaking of the lifters not rotating, none of them rotated when I took apart my 320. I thought it was because they were so coked up with carbon sludge. It took me a great while to even get them out of the bore! But, now we know the actual reason.

Would you prefer milling the block deck or the head or both, and how much would be safe? And how about the head gasket - composite or copper? During my initial build, I used composite to be on the safe side (leakage-wise), but the next time I'm going to open it up, I will use the thin copper gasket that I have in stock. I was stupid enough not to have the block deck surface milled when it was being overbored. The surface from the factory looks pretty rough to be sealed with a copper gasket.
 
Hmmm..I did'nt think making my own cam was all that "out there", just stick a hunk of metal in the lathe and remove everything that dos'ent belong there. Now as for changing the rocker ratio, this could present a problem, in that increasing the ratio to something like 1.6 or 1.7 would mean relocating the rocker arm shaft. This could be difficult. However we have a "advantage" with the buick lifters, they are 1". SBC are .825? or so. Back in the good old days, befor roller cams were not so totaly reliable, big base lifters alowed a more aggressive ramp on the cam, simulating roller cam dynamics to a point. SBC guys made lifters with a big base, a "mushroom" lifter, so they could exploit this effect. A cam grinder that says " O yeah, I remember how to do that", and can, would be cool. But my bet is it will take more meat on the core to do it. I think with more research a really advantagous cam could be made.

As for valve springs, I am using the stock stuff now but I have a new inner spring that will give me about 125 closed pressure for the new engine. Yes, more springs are avaiable for chevys, and more pressure to be sure. But!! I rockwelled the block, its not hard, about 8-10R. So are the seats. What beats the seats out is a lot of spring pressure and sustained rpm. And then theres the lifters. The hydraulics were never designed to resist a lot of pressure, if you have solids, no problem. So, I think 100-125 lbs should be more than good.

Speaking of seats. The cumbustion dynamics are not good. The engine generates a LOT of carbon. It coats everything in there. It curls up and flakes off. Some goes out the ehaust and some gets traped on the seat. Carbon is harder than the iron. The process pounds the exhaust seat and valve to death. It will look like its been shot peened. It happens fast. Some of this junk goes down past the piston, it scores the wall, wrecks the ring seal and eventualy breaks the rings and destroys the piston. A total polish job on all parts in the chamber and a really hot ignition goes a long way toward fixing this.

I've milled both the deck and the head, both to gain the compresson and to fix some problems. I found that I then had valve geometery problems. Now that I've come up with the Harley piston solution I have any comp ratio at hand that I want, so I dont mill except to clean things up. I like a copper gasket because of the heat transfer charistics. The only drain for the head is at the back of the block, and this engine I'm building things could get hot, so I am also drilling some extra holes in the deck to mix things around and cool things better. alleycat
 
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