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GIRTHQUAKE
GIRTHQUAKE Dork
8/8/20 3:19 p.m.

I’ve had a long-term dream of building some kind of straight 8-running roadster after hearing one howl when I was young, a sound honestly I really can’t compare anything to. I know that long term- like over a decade- I’d love to build SOMETHING that uses an I8 engine (probably supercharged- I want it to sound mental, and turbos muffle sound and the pulses so it’ll sound more V8-ey) but I’m finding that even basic details on the engines are becoming really scarce. Like, I didn’t know Chrysler made one until yesterday, even though I researched Buick I8s for weeks when I nearly bought a 50’ Special.

I know that I8s are, to be honest, poor engines in general- almost all of them are Siamese-port, their stroke is HUGE compared to their bore, and their rotational masses are absurd- but out of all the long boys from Packard, Buick and Pontiac which one would be the “best” to modify? The Crème’ de la Crème in other words, for someone who’s trying to wring power out of them. So far my notes say Packard and Buick, but I've got holes in my knowledge you could drive through.

Patrick (Forum Supporter)
Patrick (Forum Supporter) MegaDork
8/8/20 3:29 p.m.

I've driven a 53 buick with one and it was nowhere near as slow as my 54 chevy with the straight 6.  My son's 41 studebaker has one, but not sure if we'll use it or not.  

stuart in mn
stuart in mn MegaDork
8/8/20 3:37 p.m.

Buicks were probably used most often for high performance work back in the day, so will have the best availability of aftermarket high performance parts.

ShawnG
ShawnG UltimaDork
8/8/20 3:37 p.m.

Duesenberg would be pick of the litter. 420 cubes, pent roof chambers, ohc, 4-valves per cylinder, full pressure oiling. They're built more like a 1970s twin cam. 265hp n/a and 310 with the blower. The folks at Straight-Eight make a lot of engine parts for them now.

If it were me, I would pick a Packard. They're probably the most bullet proof and were produced the longest. Probably the best supported at the moment as well thanks to the guys at Max Merritt. Also, if you look at a Packard I8 head-on, the valves aren't parallel to the cylinder bore, they're actually canted a few degrees, letting the engine breathe better. They used an aluminum crankcase so they tend to be a more reasonable weight. 

After that would be a Buick because OHV

The Pierce-Arrow straight eights are great engines too and carried on a while thanks to being owned by Studebaker.

 

Indy "Nub" Guy
Indy "Nub" Guy PowerDork
8/8/20 3:47 p.m.
ShawnG said:

Duesenberg would be pick of the litter.

If it were me, I would pick a Packard. They're probably the most bullet proof and were produced the longest. Probably the best supported at the moment as well thanks to the guys at Max Merritt.

After that would be a Buick because OHV

Did someone say Duesenberg ?

ShawnG
ShawnG UltimaDork
8/8/20 3:48 p.m.

I've been in that museum.

I've had my hands on both of the Duesenberg Indy cars they have.

Pretty amazing stuff.

They also have a Bugatti H-16 on display.

frenchyd
frenchyd PowerDork
8/8/20 3:57 p.m.

In reply to GIRTHQUAKE :

My first race car was a 1947 straight 8 Buick.   (circle track).  Bottom end torque is what those are all about.   Dirt circle track back then was who could out pull who out of the tight corners and the straight 8 was great at that. 
     Today I'd put 4 SU carbs on one ( with a little port work ) velocity stacks, decent compression (9.5-1) and headers. Not too much cam. 
The weakness as far as I'm concerned is the combustion chamber shape. That was designed for good fuel mileage not peak power. You'll have to open that up and use the piston to gain back the compression you lose. Jahns pistons is your answer there. Both Crower and Isky will regrind your camshaft if you don't have anyone nearby. 
Don't worry about the long stroke.  Jaguar won a lot of races with a 4.17 inch stroke and is currently approaching 400 horsepower out of only 258 cu.in. With that 4.17 stroke. 
 

 

Indy "Nub" Guy
Indy "Nub" Guy PowerDork
8/8/20 4:27 p.m.
ShawnG said:

 

...

....

They also have a Bugatti H-16 on display.

Yep.

GIRTHQUAKE
GIRTHQUAKE Dork
8/8/20 5:15 p.m.

In reply to ShawnG :

Heh, Dusenberg would be the ticket if I had that kind of dosh ;)

Good point about the canted valves- I've seen mention but I haven't yet seen pictures or actual angle. I think the fight, unless different pistons and rods can be mashed in like our guy who put BMW Mini pistons in his Opel, is gonna come down to the weight between the Packard and the Buick. The former easily can get to 800lbs in a finished block.

I didn't know Studebaker bought Pierce-Arrow; doubt I could find one tho.

In reply to frenchyd:

The bottom end was the other reason for supercharger use cheeky My only 'problem' with the stroke is that there's so much meat in those rods it's kind of wild, though I wouldn't want to try turning one about 4500RPM thanks to the crank's tendency to twist itself like a braid. Really cool to hear about racing one! Sadly, Jahn's pistons doesn't exist anymore- bought up by JE and Egge prior to 2012.

 

slowbird
slowbird SuperDork
8/8/20 5:18 p.m.

I'd go Packard just because flathead engines look cool.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
8/8/20 5:25 p.m.

Two 4BTs welded together?

I'll see myself out.

My nod goes to the Packard, but I love Packards. If you haven't yet, check out Coldwarmotors on YouTube. He has a series that deals with resurrecting two I8s: one Packard, one Buick. 

Uncle David (Forum Supporter)
Uncle David (Forum Supporter) New Reader
8/8/20 5:49 p.m.

Cost-no-object answer is Duesenberg.  For the rest of us, the answers are Buick 320 and Packard 356.  Honorable Mention goes to Packard 327.  You Tube will show you a t-bucket style rod with a supercharged Packard, and there is plenty of discussion of Buick 320's on the H.A.M.B.  Don't even think about exceeding 4K RPM in any of them. 

GIRTHQUAKE
GIRTHQUAKE Dork
8/8/20 5:52 p.m.
Jordan Rimpela (Forum Unterstützer) said:

My nod goes to the Packard, but I love Packards. If you haven't yet, check out Coldwarmotors on YouTube. He has a series that deals with resurrecting two I8s: one Packard, one Buick. 

I was actaully gonna drop him a line and ask him for details! I found his channel in that series, dude knows his friggin' stuff!

In reply to Uncle David:

I dare to dream

TurnerX19
TurnerX19 SuperDork
8/8/20 9:37 p.m.

In reply to Curtis73 (Forum Supporter) :

Alfa Romeo straight 8s had the timing gears in the middle to minimize the torsional timing variations. I think your two 4BTs idea is not far of of that, and bring the primary drive out there as well to save the rear of the crankshaft.

frenchyd
frenchyd PowerDork
8/8/20 10:28 p.m.

In reply to GIRTHQUAKE :

I don't remember working on that straight 8 Buick very much. It ran pretty well until I blew a tire and mashed it up against the wall.  Heavy smoker though. Worn guides and rings. 
 

Sorry to hear that Jahns isn't in business anymore. So where is the source for oddball cast pistons other than casting them yourself?  

ShawnG
ShawnG UltimaDork
8/8/20 11:22 p.m.

JE pistons made the last set of custom order pistons we needed a couple years ago, no complaints.

Our machinist can make whatever is needed if it comes to that. Usually it's easier to start with an off-the-shelf blank and have the piston supplier modify it for our needs.

The 1910 Sears Model L engine I built uses Chevy 454 slugs that have been modified.

Our guy is building billet steel rods for the Lycoming engines in the Auburn 8-100 at the moment. We'll be tooling up for Continental 8 rods next.

You can custom build anything these days, it just costs money.

slowbird
slowbird SuperDork
8/8/20 11:45 p.m.

As long as we're talking about weird mashups, how about two Model A engines welded together? Not very powerful, but weird enough.

frenchyd
frenchyd PowerDork
8/8/20 11:49 p.m.

In reply to ShawnG :

Absolutely!  check availability of production pistons first.  You can do a lot of modification with nothing more than a Jig  and a vertical mill.  I almost always do my own valve reliefs just because it's faster.  There are several places you can get all those critical specs.  When you add custom made sleeves you can overbore past the cylinder walls, slide a top hat sleeve in and Bob's your uncle  

Custom Connecting rods I used to use Carrillo but now high quality rods in low volume are coming out of China. China is also making high quality custom billet crankshafts. 
I haven't looked at pistons lately  but I'd be surprised if China  aren't on top of that as well. It's certainly worth a look. But sometimes, the expensive pistons are worth the added cost.  Cosworth is just such a choice for Jaguars. Their forged piston is 80 grams lighter than the lightest I've Been able to find plus they have a combustion chamber shape that is worth 40 horsepower more.   

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
8/9/20 6:39 a.m.

Something I would never have thought of, is that I heard it's hard to find a good core engine because those long old-timey castings would sag in the middle because they were only supported at the ends.  Deck, mains, and cam tunnel get thrown all out of whack.

 

Wonder if an engine sitting under a tree since 1950 would be a better starting point than a ran when parked?

02Pilot
02Pilot UltraDork
8/9/20 7:44 a.m.

A buddy of mine has a 1946 Chrysler with a straight 8. I haven't driven it yet, but I really like the idea of these, so I'm hoping the experience lives up to my expectations.

stuart in mn
stuart in mn MegaDork
8/9/20 8:00 a.m.
frenchyd said:

Sorry to hear that Jahns isn't in business anymore. So where is the source for oddball cast pistons other than casting them yourself?  


 

https://egge.com  is one source for pistons for old and obsolete engines.  They offer a number of other rebuilding services as well.  I see on the front page of their website they list a complete rebuild kit for straight 8 Buicks.

 

JE pistons appears to still be a going business: https://www.jepistons.com/products/automotive  The origins of what we know today as JE Pistons can be traced back to 1912 and the Los Angeles foundry of William Jahns Sr. and his company W.H. Jahns. Employing the tagline, “Nothing but Pistons,” the W.H. Jahns company produced pistons and semi-finished pistons until 1948, when Jahns Sr. retired. Meanwhile, Jahns’ son, William “Uncle Bill” Jahns Jr., started and had been working on his company Jahns’ Racing Pistons since 1947. Shortly after, the business became Jahns’ Engineering Pistons, and was finally shortened to JE Pistons.

frenchyd
frenchyd PowerDork
8/9/20 10:03 a.m.

In reply to GIRTHQUAKE :

Before we get all excited about what can be done maybe we should know what sort of budget you'd like to work with?  
 

Starting with up to 170 horsepower / 290 ft pds Torque  how far do you want to go? 

In addition we probably should know the level of ability you bring to the table. Do you have engine rebuilding experience ?  Those old straight eights aren't complex, but if you've never taken an engine apart and then reassembled it it can be daunting.  
 
What about originality?  Do you want it to be visually of the era? With up draft carbs? Or maybe down draft carbs?  Either way you won't make as much power as side draft carbs. I think 4 side draft SU's would make the most power for the least money and be the easy button.  You could even probably pick the correct needle based on what the performance will be.  There are a lot of really long stroke engines in England during the 50's 

Finally what sort of modification experiance do you have?  Are you comfortable putting the whole package together in a cohesive manner? There are good computer programs that will let you trial fit ideas to see which will give you the most bang for your dollar. No you can't look up a Packard or Buick and just enter data.  What you do is start with similar combustion shape and change it to 8 cylinders. Change the bore, stroke etc until you replicate the original size and then make adjustments until  you duplicate the original horsepower and Torque.  How much the factory fudged the actual numbers will be how far off your finished product will be.  Because from here on it's all math. 
 

If you overbore an engine you might only add 4-7 horsepower. If you change the cam specs you might get 20-80 horsepower depending on specs. Porting, well it depends on what you're working with. Etc. 

wspohn
wspohn Dork
8/9/20 10:29 a.m.

Get creative.  How about a pair of lightly modded LNF turbo Ecotec engines putting out, say,  a conservative 400 bhp each, joined by a beefy CV joint end to end...........devil 

frenchyd
frenchyd PowerDork
8/9/20 11:34 a.m.

Bore 3&7/16 

Stroke 4&5/16 

cu in 320 

compression 7.5-1 

Approx 800 pounds  40 inches long 

top speed? 222 mph on Bonneville salt flats. 
Salt Cat 11 

max overbore .125

sleeve to .250 over use IH pistons 

there are dual carb manifolds floating around for that engine but most multi carb manifolds are fabricated. 

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