Inliners International Forums General Discussion Engines Connecting Rod - Weight and Balance

Scott, I too can't wait to read the new book. How will you be distributing it?

Thanks for the encouragement Beater . . .

integrated - the particulars of the build have been discussed on several different posts here over the years. Most of them in Bench Racing . . .

Here's a quick summary:

'49 block bored .030 over with custom pistons/pins by Ross and Hastings cm rings.
NOS Hi-Torque crank from '52 with stock journals recently polished and balanced
NOS war surplus head from '42 mildly ported and polished with particular attention to the exhaust ports.
Obscure Isky DP#2 spec cam reground by Delta Cams 247/264 - 204/232 @.050 (extended duration on exhaust lobe to promote scavenging).
Various valve train tricks from McGurk (inner springs/hold downs etc). I also have a set of Barker high lift rocker arms (not sure that I will use since cam is already lifting .41 and not sure about coil bind not to mention push rod canting/flexing).
Eddie Edmunds water heated two duece intake with twin Carter WCDs
Tube Headers with provisions to heat auto chokes
6 volt electrics with NOS '39 Delco #1110008 dizzy - preferred by Fisher because of advance curve. Modified with Harman Collins dual point conversion plate.

regards,
Keith

Im finalizing things in the last chapter of Book #1 now, but I will be the exclusive publisher and distributor for my books, so they can be purchased directly from me. As the title states, it will be a series of books, so as I acquire more props and parts to do a continuation, I will release them as they come available. But right now, I have enough material to do a Book #2 and #3.

I just bought (10) ISBN numbers so they can be distributed through major retailers.
I will be the exclusive publisher and distributor for my books, so they can be purchased directly from me.

This almost sounds counter-addictive lol

If I can't sit down and get something completed start to finish pretty quickly I lose interest in it quickly. I had been working on the Stovebolt book for almost 3 years, and finally got back on it this summer to try to finish it. Around Thanksgiving, I was waiting on some parts to get shipped for it, and while I was waiting I sat down and wrote another book from idea to final draft, cover design art and all in just 3 weeks. So now that i'm on a roll i'm going to finish up some other book projects. But its fun though.

I want a copy of the pictured Stovebolt book when it comes out. CNC-Dude, can you share what the other books are about? Titles? Thanks Jay

Sure Jay, Book #2 is going to be an assembly guide for engine building with a trip through the machine shop showing all the recommended steps for prepping a shortblock for street and performance. Book #3 will focus on cylinder head porting and modifications to complement Book #2 mods.
By breaking it down into a series of books, I can go into greater detail about each phase of engine preparation and engine building, which is my specialty.

Stock 49, that is going to be one hi-powered 216! If it's OK I'd like to learn a little more. How many cfm does each carb flow at 3.0hg? What is the total CID with the new crank and .030 over? Is the Hi- Torque crank an aftermarket part at the time? Thanks in advance for filling me in. CNC-Dude, this sounds like a great series of books to have and pass down to my Grandson. Am I correct that at least the first series of books are about the "Stovebolt" series of engines 1962 and older? Thats fine with me, I just hope that there will be a follow-on series covering the later engines. Let me know when Book 1 is avalible. Jay

Yes Jay, there will also be a series to cover the later 194-292 engines as well.

Hi Jay . . . the arithmetic on the bore and stroke mods is straight forward - call it a 230 CID (3.53 x 3.9375). I don't think I have ever seen a CFM rating published on a Carter WCD - it can't be more then 130 or 140. But the head is the limiting factor on this build.

Hi-Torque is Chevrolet branding for a bored & stroked stovebolt engine introduced in '41 for trucks (the original 235). The same engine was re-purposed in '50 on the Powerglide cars (because the automatic transmission slipped - wasting horsepower and torque. So they needed to provide more.). The crank I am using is an NOS GM part for a PG car:
Inliners BB post circa '06
regards,
stock49

Show us some pics of your assembly process.

Stock 49,X2 on the pics please! Is the head also for a 235? What I have read the "best" head is one with 848 as the last 3 digits of the casting #. Did you install the larger intake valve in the head that you are using? Has the head been milled down for a compression increase? I have to admire and respect the time and trouble that it took to find all those NOS and period correct aftermarket speed parts. CNC-Dude, glad to hear about a second series of books. Jay

Greetings . . .

I will post build pics . . . after the cold weather breaks of course!

The 3836848 head from the '56 235s is indeed a famous piece. But it is not compatible with the early stovebolts that utilized a tall push rod cover which extends beyond the block on to the head. Not to mention a different head bolt pattern.

Also, I am not milling or filling the head to get CR. Since the stroke/compression height of the build requires custom pistons - added CR is coming from pop-ups included in the piston design.

regards,
stock49

Stock 49, About an hour or so after I posted yesterday I rembered that the number of head bolts was increased sometime in the 1950's. I had forgot about the side cover differences until I read your latest post. If I was going with custom pistons I would only have the head and block checked for straightness,removing nothing from either if I did not have to.If I may ask what is the final compression ratio going to be? What valve sizes? When you do the build please post a picture of the "Jet oiling system". I and probably many others have never seen this type of system.(born too late) Jay

The deck and the head have been milled just enough to prepare the surfaces for gaskets. The valve diameters are all the same from '41 to '52: Exhaust 1.5" Intake 1.64". There are pictures of the head here:
Inliners post circa '06

In '53 the intake valve diameter grew to 1.875" but that is in the newer style (short push rod cover) 235 head.

As for the static CR for this build - I am expecting it to be somewhere north of 8:1.

Aren't NOS castings beautiful? Even 8:1 is a nice increase over stock. Compression is like almost anything else a person gets to a point if diminishing returns. Going from 7.5 to 8.5 will add more power than going from 14 to 15:1. Something that I have always wondered: 1. Why do all older engines have such a low CR ?and 2. All big truck engines also have very low CR's even in the 1960's when good gas was around? Was gas in the 1950's low octane? Look at Chevy specs for "car" 283 and "truck"283 to see what I mean. Also look at 1960's 292 engines. They did not lower compression for unleaded gas no need allready low. I take it then that newer style 235 heads valves won't fit the '41 to '52 head. Thanks Stock49 again for taking the time to teach a newbe Jay

I think that older cars had low CR because the engineers wanted to leave room for abuse in the lower end. Higher CR is harder on the lower end. A driver of a high CR engine needs to be mindful of lugging such an engine. Trouble is the I6 is a torque monster that will tolerate low RPM lugging. The same is true for truck power plants - the engineers are mindful that the operator is likely to encounter circumstances that could cause him to lug it . . . pulling a load on a grade in traffic can easily lead to lugging, even with a mindful operator armed with a tachometer.

There is also a need for higher octane fuel (which an overly cheap operator may not want to provide) . . . leading to pinging with otherwise properly set timing . . . which abuses the top end.

Low CR is a safe design construct for reliability in a world without a tach - let alone mass air flow and oxygen sensors and an engine management computer to dynamically adjust mixture and valve events . . .

What? 1949 Chevys don't have mass air flow sensors? LOL. You have jolted out another childhood memory. This time it's of my parents turning a corner in 2nd gear (3 on the tree) and the engine "groaning" a little bit because the car was just a little too slow for that gear. Going to first was not an option because of a no syncro in first. Now I can understand what would happen if this was tried in a loaded dump truck. Jay 6155

Greetings . . .

The weather has warmed a bit and the shop isn't frosty - so I got back on the die grinder:

Assembly...Rod....Cap...Pin Bolt..Rod Bolts..Dipper...TOTAL
A..........467.4...202.5...21.9.......88.7.....16.0......796.2 (H)
B..........454.8...172.0...22.5.......88.8.....17.0......755.0 (L)
C..........460.4...221.6...22.0.......88.1.....15.5......797.0 (H)
D..........443.1...198.3...22.5.......87.6.....16.5......767.7 (L)
E..........455.9...186.4...22.0.......89.4.....17.0......770.2 (M)
F..........464.1...185.0...21.9.......88.7.....16.5......776.1 (M)
Average..457.6...194.3...22.1.......88.6.....16.4......777.0 grams

Max Var....24.3....49.6.....0.6........1.8.............. 42.0 grams

Ave Var..5.310%...25.5%...2.711%....2.033%.............5.405%

Abs Var..5.484%...28.8%...2.740%....2.055%.............5.563%

The dipper turns out to be another variable . . .

Getting rid of parting lines and polishing things up reduced the variabilty quite a bit. I also focused on the shoulders of the bearing caps.
They vary quite a bit from cap to cap (thickness and in how far they extend down into the oil trough). The heavier caps definitely carry more weight here. So I can take another pass to further reduce variability.

The Scott's point I am working them in pairs 2xH, 2xM and 2xL but I am trying to get two sets of H, M and L assemblies that are about equal in weight:

Cylinder
..1.. H...796.2 |
..2.. M...770.2 |
..3.. L...767.7 -> 2334.1 grams
..4.. L...755.0 -> 2328.1 grams
..5.. M...776.1 |
..6.. H...797.0 |

Matched together into sets of three - reveals only 6 grams difference front to back.

Leading to the question - which holes should the get the heaviest assemblies? The lightest?

regards,
stock49

If it were my engine, I would either put the two heavyest in the 3,4 med in 2,5 and light in1,6. This IMHO would reduce twist on the crankshaft. From a balance standpoint it would give light,med,heavy,light,med,heavy. Another way to consider 1,2 light,3,6 med,4,5 heavy. This would give light,heavy, med,med,light heavy. Probably the second way would be the smoothest. A tough call to make. Jay 6155

Stock49,
Is that the best that can be done to bring the rods into balance?

No. That's just the second pass. I think I can do better.

It's too bad caps can't be magically switched between rods. If that was possible you would be a lot closer. Jay 6155