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My machinist buddy Jeff says the 400 SBC blocks are nortorious for ring leakage if a block plate is not used due to the closeness of the head bolts to the bores. More so than normal bore SBCs.
The 2K paint is definately stronger and more chip resistant. The Duplicolor is easily chippable lacquer.
One block painting tip I have read about is to heat the block with a propane torch to dry any oil or water out of the pores before painting it.
Never tried it but it makes sense to me, especially with the left over oil.
I used acetone to wipe mine down before painting, and that was a PITA with paper towel fragments everywhere due to the rough casting edges.
The deck was machined to a 9.00 inch / zero deck so I could select from the much larger variety off-the-shelf pistons and gaskets to achieve 0.040 quench and static compression I want. The Dart SHP decks are thicker than stock Chevy, so I am not compromising anything. I could have left the deck taller, and had custom pistons made with taller compression height, but I decided to go to 9.00-inch deck, saving money and time, and it’s obviously a very common thing on SBC engines, with lots of pistons and gasket sizes to choose from to get compression ratio where you want it. It was very difficult to get the pistons and specs where I wanted them, without making it even more difficult with a taller deck height.
Decisions
What I don’t like about the Dart SHP block is the lack of coolant bypass provisions a Chevy block has, nor do I like their design of big block style oil drain slots in valley center, versus the multiple drain holes on front to back of an OEM SBC block. I am not sure what they are trying to “fix” with these changes over the original SBC design.
.
Zero deck means that it can't be trued in the future. The real cure for block deck distortion is head studs. I use .027 Thickness MLS gaskets without failure to get correct quench.
The Dart block is superior to OEM 400 in cooling the rear cylinders. The water jackets hold more volume and all the head stud threaded holes are blind and never leak. I use an intake that allows correct coolant flow from the back hotter cylinders. The blocked off cam valley is there for a reason. The main one is windage. I use valley vent tubes so NO oil is running down on the crank.
Blocks can be painted a variety of pretty colors! Some paints are very oil resistant.
My 4.125 bore with vent tubes and using silly putty to clay the valve lift. Because I advanced the cam for more bottom end TQ
Scat Forged Standard Weight Crankshafts - Scat forged standard weight crankshafts are designed for street or race engines with substantially increased horsepower. These crankshafts are precision-ground, heat-treated, shot-peened, inspected, and micro-polished for superior tolerance control. Scat crankshafts are also nitride-hardened for superior wear resistance, have straight-shot and chamfered oil holes, and feature lightening holes in all rod throws. They also have a large radius on all journals for improved strength and wear resistance.
While the first engine had a Callies Compstar forged crankshaft, this Scat forged crank is more than adequate for my mild driving style and is less expensive. I even considered their cast crank but stuck with forged. This is the crank I wanted on first build.
Scat Pro Comp Forged 6.0 Inch I-Beam Connecting Rods - PN 2-ICR6000-7/16.
Summit Price - $483.99
Scat Pro Comp I-Beam Connecting Rods - These Scat I-beam connecting rods incorporate all of the best features possible for an I-beam rod, including some strength adders found in H-beam designs. Scat Pro Comp I-beam connecting rods are profiled with clearance for long stroke applications. These connecting rods feature a one-rib cap design for added strength and bearing support, polished beams to eliminate stress risers, and special hollow dowels with huge 7/16 in. ARP cap screw bolts to greatly increase strength and horsepower capabilities.
This is one of the substitutions I made on the CNC Motorsport short block list, replacing the Scat H Beam rods with these Scat I beam rods. These were less expensive than the H-Beam rods in the engine package, but the price was offset by the more expensive pistons I chose. And again, I chose these Scat rods over the Callies Compstar H beam rods used on first engine…. because they are more than adequate for my use. I did not upgrade the ARP bolts to the stronger option offered, because the standard ARP bolts are adequate. These are the rods I wanted on the first build.
ACL Main Bearings - PN 5M909H-STD – Standard Size – Summit Price $79.99
ACL Performance Race Series main bearing sets deliver everything performance bearings should be by utilizing design, metallurgy, engineering, precision quality control, and of course, years of knowledge and experience. Main bearings feature multi-layered tri-metal copper alloy construction that blends characteristics to provide high strength and excellent seizure resistance. They are manufactured to exact tolerances ensuring a reliable fit and helping to maintain consistent clearances. Main bearings are augmented with extended grooves, as well as other bearing enhancements, like increased crush, bearing eccentricity, and enlarged I.D. chamfers.
ACL Rod Bearings - PN 8B663H-STD - Standard Size – Summit Price $103.99
ACL Performance Race Series Rod Bearing Sets - ACL Performance offers Race Series rod bearing sets for a wide range of vehicles. These high-performance tri-metal engine bearings are designed to withstand higher RPM conditions. They feature a high-strength overlay plate with reduced thickness for improved fatigue properties.
* Hardened steel backs on all rod bearings to improve the support of the bearing lining and assist with bearing retention in the housing.
* Increased crush for improved bearing retention
* Elimination of flash plating on the back of the bearings to improve heat transfer through the bearings and to maximize the grip between the bearings and its housing
* Increased eccentricity to compensate for bore distortion at high RPM and to assist in the formation of hydrodynamic oil films
* 3/4 in. grooved main bearings to optimize bearing load carrying surface area and oil flow to the conrod bearings
* Tight consistent wall tolerances to help you maintain consistent clearances
* Enlarged ID chamfers on bearing edges (where required) to accommodate large fillet radius on performance crankshafts
If you're building up a Dart block and want the best bearings with the correct sizing, then you'll want Dart cam bearings. They're fully grooved, made from steel-backed babbit, and specifically designed for high performance use. To all of this, Dart adds their own moly-PTFE coating for even better performance and durability. This coating is approximately 0.0005 in. thick, which translates into 0.001 in. less overall clearance.
Freeze Plugs, Cam Plug, Dowel Pins and 1/4 inch NPT Galley Plugs
Last edited by Torqued Off; 03-07-2024 at 12:21 PM.
Glad you are back and moving forward.
I’ll be following along.
My engine sat in my garage for several years and didn’t rust.
Oil it, bag it, make sure it gets good air ventilation through that crate and put the crate on some 4 X 4’s.
Pistons - SRP Pro 4032, 4.125 in. Bore, 1.125 CD, Inverted Dome/Dish,-16 cc Volume - PN SRP-329518
Summit Price - $953.88
SRP Professional pistons combine forged piston durability with modern performance technology for an extremely capable forged piston kit that doesn’t break the bank. Forged from 4032 aluminum, SRP Pro pistons experience minimal thermal expansion, making them perfect for a high-performance, reliable engine build from the track to the drag strip. All SRP Pro pistons include premium ring sets, wrist pins and locks. As with all JE Pistons products, SRP pistons are made 100% in the USA.
· Forged in the USA using 4032 aluminum, yielding tensile strength and minimal thermal expansion
· Proprietary Forged Side Relief (FSR) forging design minimizes friction and power loss with reduced skirt width and saves additional weight with a shorter wrist pin
· Low-friction skirt coating reduces wear and reduces operating noise while optimizing performance
· Includes high-quality wrist pins, locks, and JE Pro Seal premium piston rings
· Accumulator groove helps reduce pressure from combustion gases, reducing ring fluttering and improving ring seal for consistent power
· Made 100% in the USA
This was the second substitution I made on the CNC Motorsports short block package. The package came with the basic SRP piston, similar, but this SRP Pro version piston had skirt coatings, lighter weight, accumulator grooves and JE Pro piston rings. I chose these pistons carefully for multiple reasons.
One, I wanted forged pistons versus cast or hypereutectic, for the strength, durability, and detonation damage resistance. The 4032 material expands less than alternative 2618 material, allowing initial tighter piston to bore clearance, providing less start up piston rock and noise. I believe it’s the best choice for a high compression, strong street engine.
Two, the D-shape / inverted dome relief in this piston provides the best quench pad when matched with the AFR heads combustion chamber, which alone has a great design to induce swirl, and in combination they provide great squish/quench for best fuel burn possible, reducing detonation, better fuel efficiency, etc. This is what has been the industry standard and best recommendation for many years, by many of the experts….and is undeniably the right choice. That is why I chose the similar custom Wiseco D-shaped pistons from Skip White on the first build.
And of course, three, I needed the right piston volume to get the compression ratio I wanted, as well as bore diameter and compression height needed.
Last edited by Torqued Off; 03-06-2024 at 08:26 AM.
JE Pro Seal Piston Rings (included with the SRP Pro Pistons)
Beyond the D shape design, these SRP Pro pistons, are Made in USA by JE Pistons, and include many of the best piston / ring features available. They are very light at 385 grams, have skirt coating for improved wear, as well as accumulator grooves for the rings to help sealing. They come with JE Pro Seal Piston rings, the best rings JE makes.
- Top ring is 1.2 mm Carbon Steel Nitride.
- Second ring is 1.5 mm Iron Phosphate Napier Style for better oil scraping
- Oil control ring is 3.0 mm Carbon Steel, Chrome faced, Standard Tension
I struggled with this decision because of the often stated / theoretically possible oil consumption issues with thinner rings. But after a great deal of research across many forums and other sources, I decided this piston / ring set is the best choice for me. While there is argument about possible oil consumption issues, there are just as many, if not more, who believe these thinner rings are BETTER for longevity, proper seal, performance, and preventing excess oil consumption. Mahle has changed their entire catalog of ring options to even thinner rings than these. Many modern engines are using thinner rings. And there is more to it than just thickness, the materials and coatings have changed and developed to make them work as well as they do. Obviously, thinner rings provide less friction from less surface area and less radial tension required, which equates to less heat, and more power to the crankshaft.
Past these theories and opinions, my direct experience is with my 2006 Corvette LS2 400HP engine, which uses a 1.5 / 1.5 / 3.0 mm ring set and I have ZERO oil consumption between oil changes. That is direct experience, not theories posted on forums or online magazine articles. And there is no evidence I can find that these thinner rings are wearing out on C6 Corvettes any faster than any other rings. LS engines are making 100,000 plus miles easily, of course for many reasons, but if piston rings were wearing out prematurely, they would not be.
The only alternative I considered would have been the traditional and thicker 1/16 -1/6 -3/16-inch rings set. Nobody complains about oil consumption with these.
What is interesting is that:
- 1.2 mm top ring is only 0.00059 inch smaller than 1/16 inch top ring.
- 1.5 mm second ring is only 0.00014 inch smaller than 1/16 inch second ring
- 3.0 mm oil ring is only 0.0028 inch smaller than 3/16 inch oil ring.
Reality check - That is not much. When you add the better materials, design and coatings these newer rings incorporate, the opposing argument gets weak.
I made a choice. I hope I don’t have oil consumption issues. It is not an easy task to get all the features you want, especially when choosing off-the-shelf pistons. I was trying to avoid “custom” pistons due to cost, wait time, etc. so I researched every off-the-shelf piston made, and the ring size was one factor, but not the only feature that mattered to me. All features had to be considered, including the 4032 piston material, correct compression height required, and CC of the piston combined with the inverted dome / D shape needed to get the minimum compression ratio I wanted.
If there is any possible compromise, it is the thinner rings, and that is a compromise ONLY if you listen to those who believe they cause higher oil consumption. Fact is, everything else is better with thinner rings. Time will tell if I made the right decision or not.
With these pistons, and my heads, I will be at about 10:1 static compression ratio, which is less than the 10.5:1 I had on the first two builds. I will talk more about that later when I discuss the heads and cam I chose.
Last edited by Torqued Off; 03-05-2024 at 05:58 AM.
Engine Paperwork - Another Lesson Learned the Hard Way
CNC Motorsports has the professional courtesy to provide me with all the actual balance specs, bearing clearances,dimensions and torque values applied, detailed on two forms.
One form is titled “Bob Weight Specifications” and formulas, with actual weight, calculations, and the end result of how close the balance was in grams. Included initials of the guy who did it.
The other form is the “Blueprint Form” with everything….date, engine block serial number, measured dimensions on crank and rod journals, rod side clearances, crank thrust clearance, bearing clearances, piston diameters, bore diameters, piston to bore clearance, ring end gaps, and deck heights. It also includes the torque values for the mains and rods. And it identifies the part numbers of the bearings used. Including the initials of the guy who did it.
In addition, the CNC Motorsport short block packages listed on their website identify the parts installed. There is no mystery, or "secrets".
The second part of this “paperwork” thing, past having the specifications, torques, clearances, etc is having the actual paperwork that comes in the box with the parts. I have been buying car parts, motorcycle parts and airplane parts for over 40 years, and there is almost ALWAYS paperwork in the box, maybe instructions, specifications, descriptions, warranty information, and the inevitable “stickers”. If I paid for the parts…. I want all that stuff.
The bonus with CNC Motorsports is you are buying a short block package, that is selected from their website, with ALL the parts listed, so, I already know what the parts are, but I still want the paperwork. A more practical point.....what if you ever need to replace a part....it would be nice to know what the part number is. CNC Motorsports keeps records of all their builds so if some issue comes up, they can refer back to the information they provided with the engine and shortblocks. Lastly, if you ever go to sell an engine, buyers like to know what's inside. Its all just comon sense.
Its probably my 20 plus years of aircraft maintenance / inspections that make me a "paperwork guy". Aircraft maintenance is completely documented in logbooks, with descriptions of what, when and how it was done. Parts have to be approved and include specific paperwork that shows they are not unauthorized "bogus" parts installed. Piston aircraft engine builds are documented with many of the same clearances, torques, etc that we look for on car engine. Turbine engines have their own unique requirments for balance, etc. In aviation......its not optional.
My recommendation....when talking to anyone about building an engine, ask them if they are going to provide a full spec sheet and all the papework.......if they say NO or make excuses, run away as fast as you can,......no matter who it is. Its a bad sign and a huge warning flag.
Last edited by Torqued Off; 03-07-2024 at 01:10 PM.
Thanks Pat. Glad someone is interested in my nonsense. The timeline is unknown. My first priority, between my hectic work schedule, is to get my Harley back on the road with its rebuilt engine, and after two years of it off the road, I can't have another summer without it. Once that is done, then I move to the 77 engine rebuild. I hope I will get the car on the road this summer....but as I said...Harley first.
I said I won't comment on your engine build. And I am biting my tongue.
You say your on hold as you need to get your bike on the road.
This, this I will comment on.
In the photo we see a early twin cam bagger chassis. Engine is already installed.
For reasons unknown and nothing to do with rebuilding the engine, the rear wheel is out.
As the engine is already in the chassis and I see stabilisers already bolted up.
It looks like you are LESS THAN 6.5 hours from onroad!
Seriously?
Put the primary together, top up the fluids. Hang the exhaust, mount the bags and go for a ride!
Then on with your super expensive car engine!
I said I won't comment on your engine build. And I am biting my tongue.
You say your on hold as you need to get your bike on the road.
This, this I will comment on.
In the photo we see a early twin cam bagger chassis. Engine is already installed.
For reasons unknown and nothing to do with rebuilding the engine, the rear wheel is out.
As the engine is already in the chassis and I see stabilisers already bolted up.
It looks like you are LESS THAN 6.5 hours from onroad!
Seriously?
Put the primary together, top up the fluids. Hang the exhaust, mount the bags and go for a ride!
Then on with your super expensive car engine!
Absolutely! There is not much left. Engine upgraded to 98 inch, transmission overhauled. So, I am replacing the bearings in the inner primary and clutch, and a SE clutch upgrade. It won't take long now. Its a 2004 FLHR Road King, I bought it new in Cincinnati, those were back in the days you had to order the bike cause they were going off the sales floor faster than they could make them. Before that, I had 73 FLH I restored frame up. I loved that bike too. IMO, a Shovelhead is the TRUE American Icon. I have owned a long list of Harleys.
Last edited by Torqued Off; 03-06-2024 at 11:08 AM.
One ALWAYS replaces the inner primary bearing. This would be in my 6.5 hour timeline.
Geterdone Mate! Sounds like a lot of effort for such an old Harley.
Did you know a baby big twin is a 107 nowadays?
And you should ride one of these VVT 121's!
One ALWAYS replaces the inner primary bearing. This would be in my 6.5 hour timeline.
Geterdone Mate! Sounds like a lot of effort for such an old Harley.
Did you know a baby big twin is a 107 nowadays?
And you should ride one of these VVT 121's!
Nahhh, I am a classic Harley guy. They ruined the bike when they changed the 5.0 gallon tank to the bloated bigger and uglier version, and narrow front wheels. That original 5.0 gallon tank shape is pure Harley art and goes way back to the 65 FLH, which is what a Road King is patterned after. Once they ruined that, I quit looking at new bikes. The entire line is an abortion and a real shame they ruined what was an American icon. Even the real Sportsters are gone, replaced with some *** like version of a Harley.
Its actually very funny, but sad.. For years, the Japanese manufacturers created Harley wannabee bikes, patterning the designs directly off the Harley to attempt to capture (blatantly steal) some of the massive dominance Harley had.......and slowly but surely, Harley gave up on their long standing and successful traditions and designs that built them into their massive success, until ultimately Harley became more like the Japanese versions of a Harley than the true American Harley. Pretty pathetic in my opinion....Since the early 2000's we have nothing left of the American Icon it once was. There isn't a new Harley I would own.
But heh, what do you expect from me? You called a 2004 Road King an "old Harley"...now that is funny.....I am a Shovelhead guy....the most beautiful and coolest sounding motorcycle engine ever made.
And 98 cubes is all I need.
Last edited by Torqued Off; 03-06-2024 at 02:50 PM.
I’ve owned six Harleys and thirteen mc’s overall.
One Dyna Superglide, one Dyna Lowrider and the other four were Softtail Fatboys.
My friends and neighbors thought I was nuts.
I’d bring home a brand new bike and within a week it would be completely disassembled and I’d build it the way I wanted.
I miss riding, but it’s so unsafe to be on a bike in California I gave it up and sold my last Harley about 8 years ago.
Hey 4-Vettes, just remember what would take you 6.5 hours might take us 6.5 days.
CNC Motorsports targets the rotating assembly balance to within 2.5 grams. As it turns out,on the this rotating assembly from CNC Motorsport, their paperwork shows the balance of 0.99 grams front and back. Less than one gram.
Now…I really don’t know much about engine balancing, but that sounds pretty good.
I certainly do not understand, nor care to understand, all the information provided, nor how they calculate all this balance, but if its anything like balancing turbine engines, there are accelerometers/ pickups on the shafts and the output tells them the relationship to perfect zero balance. Whatever type of dynamic balance machine they use, you rig it up with the calculated bobweights, spin it, and and it spits out a balance measured in grams at the front and rear of the shaft. And I believe on a SBC, you remove metal from crankshaft throws by drilling out material, or if you need to add it, use a heavy metal insert.
Last edited by Torqued Off; 03-07-2024 at 12:26 PM.
They all look good and close to what is expected, except I was a little surprised the main bearing clearances were set 0.0032-0.0035. Everything I have read talks about the recommended clearance is roughly .0010 inch per one inch of journal diameter. So with a 2.50 inch journal, you target around 0.0025 bearing clearance. I did some forum searches, googling, and found that this subject has as much bickering about it as “what’s the best engine oil to use”. Typical nonsense.
Some people believe in running real tight,…tighter than 0.0025…..but the danger is the reality of tolerances, bore alignment, and even tolerances on measuring accuracy could end up with a far too tight situations, resulting in bearing damage. I don’t know the benefits of it, but some of what I read suggests it can extract more power?? I don’t know, or care to know. I certainly don’t want any seized or damaged bearings. So not interested in "tight".
Some people believe in running looser clearances, in fact far more loose than mine. The theory is that a small increase provides a good safety margin for errors in bore alignment, and measuring accuracy and it provides a marginally thicker oil film…remember we are talking about the difference between 0.0032 and 0.0025 which is 0.0007. On real high HP engines, the bearing clearances can be real high?? Again, don’t know, don’t care. But I do know I like safety margins.
I called Chris at CNC Motorsports and asked him about it. He said its not a mistake, they run the clearances like that on most of their builds like mine, because the old school 0.0025 inch target was for stock production engines, and with the higher HP builds of today, using aftermarket high performance parts, they believe it’s better to have some extra margin to ensure those forces don’t create overheating, and bearing damage. They do it all the time, on purpose, and its worked out very well.
A couple points of interest:
- As you can see on the form, the measured main crank journals are all at 2.448, and Chris says most of the crank manufacturers machine them with the 0.002 smaller size to automatically provide additional clearance when combined with standard size bearings. He believes they do that on purpose to “help save people from themselves” and ending up with too tight clearances.
- Bearings come in oversize / undersize in 0.001 increments, and you can mix them to make increments of 0.0005 to get it closer. You pair one standard size with one oversize to reduce total by 0.0005 inch. And he said they have boxes of oversize and undersize bearings, and if their builder thought he needed to use them, he would have. He didn't.
- The danger in bearing clearances being too loose is low oil pressure.And some of what I read states that with real excessive clearances, way more than mine, you can lose the hydraulic wedge needed to protect the crank and bearing. Not an issue on this short block.
- The Dart SHP block is a “priority main” design, which means oil goes to the crankshaft main bearings BEFORE it goes to the cam. Stock SBC is the opposite. The idea of the Priority Main system is to put full oil flow from the pump to the more critical main bearings and rod bearings, and then feeding the cam that is running half the speed and less load. Makes sense.
- Dart SPECIFICALLY states in their instructions that you should NOT run a high-pressure or high volume oil pump on this SHP block. And Chris stated the same thing, and he said people have done it and the pressure was so high, it blew the filter off the engine. He said you can use a 10% higher volume pump, but it’s not necessary. The priority main oiling provides ALL the necessary lubrication and cooling for the engine by its design and needs no further help.
- Chris said to use 10W30 oil, with a standard pressure / volume oil pump and there will be no problems with the lubrication system with my main bearing clearances.
I am sure there are lots of opinions on this, as I said, I already can see it on the forum research I have done… people who believe in tight clearances, others loose……just as bad as “oil threads, Amsoil, cold air induction, and all the other never-ending forum back and forth nonsense. AndI am not interested in debating it further here.
I am comfortable with what Chris told me at CNC Motorsports. If they set the clearances loose on purpose, on a Dart SHP Priority main block, using 10W30 oil, on lots of engines, and they all work just fine, then it should work for me. Again….time will tell.
Last edited by Torqued Off; 03-07-2024 at 12:28 PM.
Well, thats about all I got for the short block information. Once I get it out of the crate and on the stand, I will add some pictures. At this point, I am very satisfied with CNC Motorsports. The did what they said they would do, and did it in the timeline they said they would. No excuses and failed promises.. And, they provided me with all the information I should get when I pay for it. And anytime, and every time, I have called them, they answer the phone, and take whatever time it takes to answer my questions, and I have been satisfied with the answers given. I have become pretty good at sorting out BS when I hear it. Chris seems very knowledgeable. Its at least a good start.
Last edited by Torqued Off; 03-07-2024 at 12:28 PM.
Glad you showed the paperwork for the clearances because if they were really .025 - .035 you would have been having problems when you fired up the engine. you've been leaving out a "0" when you typed the clearances.
Glad you showed the paperwork for the clearances because if they were really .025 - .035 you would have been having problems when you fired up the engine. you've been leaving out a "0" when you typed the clearances.
Pat
Thanks Pat......I'll fix that. Yes, that would have been a problem!!!
Last edited by Torqued Off; 03-07-2024 at 07:12 AM.
03-04-2024, 09:32 AM
Some paints are very oil resistant.
