Exotic "SOUNDING", high revving V8! Read "ENTIRE" thread before posting!!!

[Challenger]

It isnt a small high revving v8.. thats why.

[OlderThanMe]

that looks like a 1 up, 2 down, 1 up flat plane crank, is that sized to fit a Small block chev? or a ford? or just drawn with generic diamensions simply to get some practice in arranging things in the program you are using?

 

Yes it is organized like a standard 4 cylinder crankshaft. (ala most of the flat plane V8 cranks: Ferrari, TVR, etc...)

It is drawn to fit a particular engine..... but could easily be altered to fit any of the above.

 

I still have a lot of work to do on bearing surfaces.

 

There are numerous problems with a flat plane crank that has no counterweights. Mainly with chrankshaft twist and bearing wear factors.

 

Josh817:

"have someone build you a bottom end"

Umm...how much thinking have you done on that subject? That is going to cost $20,000+ to get a home designed shortblock made. Do you understand how much design work it would be to engineer a complete shortblock?

 

Vibration, block integrity, oiling, crankshaft twist, bank offset, timing chain design, mating to a transmission somehow, etc.........

 

~~~~~~~~~~~

 

Crankshaft counterweights are a must. Before talking about not having counterweights and having an uber light weight crankshaft, one should read some books on crankshaft dynamics.

[Jerminator96]

Crankshaft counterweights are a must. Before talking about not having counterweights and having an uber light weight crankshaft, one should read some books on crankshaft dynamics.

 

Even with a boxer engine?

[Pete84]

I really don't remember seeing any pictures of say, a Ferrari or other flat plane crankshaft. That might be a nice way to judge the amount of counter weighting. Or some technical specs, weight of pistons, rods, counter weights. Might not be possible, but hey, might be out there.

 

Just a thought

[OlderThanMe]

Even with a boxer engine?

 

Once again I'll say: find some books on crankshaft dynamics and read them. There is a lot more going on than you realize.

 

This is off topic but counterweights are necessesary for crankshaft durability and main bearing life.

Costworth Subaru crank, probably a CAD image (note the aproximately 30%-50% counterweights with one counterweight per lightened rod pin):

It is 18.01lb compared to the stock 20.4lb.

 

Pete, Here are some pics of an OEM Ferrari 355 crankshaft and bottom end during rebuild (Note the MASSIVE main bearing surface area):

 

[Clifton]

Without going back through 21 pages to see if has been brought up. I found that Lotus used a flat plane crank in the LT5 they used in there GT1 Elise. I remember it being mentioned that an LS might be too large for a flat plane but the LT5 is similar is size.

[Jerminator96]

Once again I'll say: find some books on crankshaft dynamics and read them. There is a lot more going on than you realize.

Oh I doubt it's that much more than I realize. I have no doubt of the benefits (and in the need of longevity the necessity) of counter weights, I was just proposing that in a boxer eight they wouldn't be absolutely necessary. Bearing life would be awfully short though, and I don't think 4340 would be quite as rigid as you would need it to be.But then there is always the 360 degree crank that would have even less need, but that is getting counter productive in terms of engine speed.

[Guest BonesDT]

I'm pretty sure there are posts regarding High RPM valve train dynamics as well

 

Pretty sure is not definite. Please memorize the entire thread before you post.

[Gollum]

Gollum, how did you decide on counterweight mass? Have you done any stress/distortion math on it?

 

 

 

No... Ummm, that crank design was made in about an hour wasted at work (I'm such an evil man I know) using inventor. I was semi-copying the Hartley V8 3.0 liter crank. The dimensions are based off of the stock pieces in inventor (con rod, crank, etc). I wanted to use the stock rods, so I just built it to those specs.

 

I figured once I get the specs I'm looking for on the ford small blocks (5.0 in particular as they're everywhere) then I'll spent some time at home working on replicating the block and designing a flat plane crank. I wouldn't really be doing this to actually put it into production, but simply for the entertainment and education factor it presents. It's something interesting enough to keep me working with software I don't completely understand and helps me grow in many ways.

 

Your design is in many ways far superior to mine.

 

I must say I still wonder if a 100% counterweighted crankshaft would be necessary, though I understand why it's much safer. Though if we're taking an american V8 and shortening the stroke down to 2-2.5 inches then it can be a pretty light crankshaft ANYWAYS. Reving to 15k shouldn't be limited by the crank...

[Jerminator96]

I figured once I get the specs I'm looking for on the ford small blocks (5.0 in particular as they're everywhere) then I'll spent some time at home working on replicating the block and designing a flat plane crank. I wouldn't really be doing this to actually put it into production, but simply for the entertainment and education factor it presents. It's something interesting enough to keep me working with software I don't completely understand and helps me grow in many ways.

 

Your design is in many ways far superior to mine.

 

I must say I still wonder if a 100% counterweighted crankshaft would be necessary, though I understand why it's much safer. Though if we're taking an american V8 and shortening the stroke down to 2-2.5 inches then it can be a pretty light crankshaft ANYWAYS. Reving to 15k shouldn't be limited by the crank...

 

I don't think he ever meant to say 100% counterweighting was necessary. I'm curious as to why you would choose the SBF over SBC? We all know that a SBC pushrod motor can work at 9500rpm (possibly higher) but maybe the SBF can too?15000 rpm is a lengthy goal. I believe the Chevy blocks failed when they were tested that high in the 80's (something about cylinder walls collapsing).

[OlderThanMe]

Your design is in many ways far superior to mine.

 

I must say I still wonder if a 100% counterweighted crankshaft would be necessary, though I understand why it's much safer. Though if we're taking an american V8 and shortening the stroke down to 2-2.5 inches then it can be a pretty light crankshaft ANYWAYS. Reving to 15k shouldn't be limited by the crank...

 

Thanks Gollum.

100% counterweight is definitely better as far as bearing wear goes, but in no way will it solve all of the problems with bearing wear. You are always going to have some wear on the bearings with pressures from combustion bushing on the opposing half of the bearing etc...

From my observations of flat plane V8 crankshafts, a standard racing counterweight is in the ballpark of 50%.

Som people may be confused by the percentages I have been talking about, but it is simply how much mass is on one side of the crankshaft compared with the directly opposite side.

100% counterweight is actually a little bit lighter than a standard cross plane crankshaft of the same stroke. Cross plane crankshafts have 100% counterbalance plus a portion of the connecting rod and piston weight added on as well.

 

The nice thing about the SBF is you can buy a new OEM block from summit for about $500.

 

 

The flat plane crankshaft that I designed with 100% counterweights actually weighs about the same as the longer stroke cross plane crankshaft that came out of the engine. Reason being that with a shorter stroke you can remove less material inside of the conecting rod journal. With an extra few millimeters of stroke I was able to remove some more weight at the sacrifice of crankshaft durability. (less main-rod bearing journal overlap and less material)

 

Jerminator, lets not get all up in a wad about counterweighing.

The SBF has better distributor placement for one. Also a smaller bore which is better for a high reving, small bore, small stroke, V8 Braaaaaaaappppp motor.

 

 

 

 

 

Now...

Single cam V8 vs. DOHC V8.

 

First of all, you will need custom camshafting, which is MUCH cheaper with a single camshaft.

Most quad cam V8 heads are good to 7000-8000RPMS with OE parts(with adequate prep work). The problem is that at $250-$400 for custom cams, that can add up quite quickly with 4 cams.

With a single cam engine ALA SBC, SBF, etc... you only have one camshaft to buy but there is a lot of other valvetrain gear to survive the high RPMs.

NASCAR engines live at 7500-9300 RPMS all day long for 500 miles so that isn't too difficult to come up with a valvetrain that can live at those RPMs.

 

 

 

Is there a way to make it feasable to use a DOHC V8 engine and not be out $1200-$2000 in custom ground camshafts?

I say yes but I have to punch some numbers first to see if my ideas are even remotely possible.

[Gollum]

But what DOHC options are there that are affordable and fit in our Z cars? These are the only ones I can think of off the top of my head:

 

1UZFE (fitment is iffy. doable, but poorly documented)

VH45DE (doable, probably best option)

VK56DE (we all love the VK, but how many swaps have been done. and $$$?)

Ford DOHC 4.6 (not TOO expensive, but huge and hard to find in the junkyards)

 

 

News Flash

 

I was going to mention this in my last post but forgot about it.

 

Coates Internaional Ltd. - Makers of the patented spherical valve technology are finally going to be making an effort in racing. They're going for a landspeed record. They havn't announced what class yet, but it will most likely be Section 5. As they outlined that section in their press release.

 

This is big news. If Coates finally starts to break through in the performance market, and we see someone team up with them, like edelbrock, we could see heads to make a SBC or SBF rev to 15k (if the crank will do it) and make more power than ever. But at what price??? Only time will tell. But for the high RPM crowd this IS interesting news.

 

Edit:

 

To Olderthanme ~

 

Check this out. I think the notches in the couterweights are to gain clearence to be able to remove more weigh from the rod bearings, yes??? Will it really be that hard to remove weight from your crank design? Another added benefit I was just thinking about, is that though your crank weight might not be too much lighter, won't the shorter stroke mean the weight is closer to center, thus it should still "feel" lighter due to the lower rotational inertia. Do I have that right?

 

[Gollum]

I don't think he ever meant to say 100% counterweighting was necessary. I'm curious as to why you would choose the SBF over SBC? We all know that a SBC pushrod motor can work at 9500rpm (possibly higher) but maybe the SBF can too?15000 rpm is a lengthy goal. I believe the Chevy blocks failed when they were tested that high in the 80's (something about cylinder walls collapsing).

 

Sorry for the double post. Didn't see this post at first due to it being on a different page.

 

 

I choose the SBF for many reasons, chiefly among them because I'm a ford guy. Hey, at least I can admit it.

 

I'm sure others will prefer the SBC for various reasons, all very valid. But my reasons are just as valid and if they don't see that then they're purists. Everyone should be able to respect another's engine choice.

 

Oh, and the RPM limits of the SBF and SBC are a moot point. Everything I've seen suggest the block has nothing to do with the limits. Stroke, crank, rods, pistons, rings, and valve train are all major players.

[Jerminator96]

Jerminator, lets not get all up in a wad about counterweighing.

The SBF has better distributor placement for one. Also a smaller bore which is better for a high reving, small bore, small stroke, V8 Braaaaaaaappppp motor.

Agreed, no sense in arguing about counterweights when you will probably never build a 100% counterweighted crank (unless you're really going for longevity) and I certainly have no reason to build a 0% crank.The distributor placement is a valid point but I would almost certainly use a crank-trigger and coil-per-cylinder on this hypothetical engine as I've never cared for Chevy distributors.Somebody is going to have to explain what is meant by 'small' V8. Are we talking 2.4L F1 sized motor, or 4.0L Toyota V8? I think a 4.125 bore on a Chevy 'aurora' block with 8.3'' deck and a 2.5'' stroke makes for a great motor that you could rev to your hearts content. But then again I'm more interested in making power (hence the big bore) than revving over 10k.Gollum:I don't blame you for being a ford guy. I'm a hard core Chevy guy but it always ends up when I want a good reliable daily driver I roll away in a Ford.

[OlderThanMe]

But what DOHC options are there that are affordable and fit in our Z cars? These are the only ones I can think of off the top of my head:

 

1UZFE (fitment is iffy. doable, but poorly documented)

VH45DE (doable, probably best option)

VK56DE (we all love the VK, but how many swaps have been done. and $$$?)

Ford DOHC 4.6 (not TOO expensive, but huge and hard to find in the junkyards)

 

 

News Flash

 

I was going to mention this in my last post but forgot about it.

 

Coates Internaional Ltd. - Makers of the patented spherical valve technology are finally going to be making an effort in racing. They're going for a landspeed record. They havn't announced what class yet, but it will most likely be Section 5. As they outlined that section in their press release.

 

This is big news. If Coates finally starts to break through in the performance market, and we see someone team up with them, like edelbrock, we could see heads to make a SBC or SBF rev to 15k (if the crank will do it) and make more power than ever. But at what price??? Only time will tell. But for the high RPM crowd this IS interesting news.

 

Edit:

 

To Olderthanme ~

 

Check this out. I think the notches in the couterweights are to gain clearence to be able to remove more weigh from the rod bearings, yes??? Will it really be that hard to remove weight from your crank design? Another added benefit I was just thinking about, is that though your crank weight might not be too much lighter, won't the shorter stroke mean the weight is closer to center, thus it should still "feel" lighter due to the lower rotational inertia. Do I have that right?

 

 

Gollum, All of the above V8 engines are good candidates if a cheaper camshaft solution can be utilized.

Also the VH41 and VK45 could be utilized. The VH45 is realy cheap and really available. The VH45 has better heads than the VK by a little bit. The VH45 has slightly larger valves than the VK45.

Also comparing the VH to UZ, the VH intake runners are much better as far as flow goes. You can see most of the back of the intake valve on the VH heads where you can barely see the intake valve at all on the UZ head.

Then there is all the voodoo about the VH weighing 500 pounds... Maybe if you have all of the emission and other junk on there. I bet the longblock could get down to 350 pounds if you really tried. (The VH valve covers are like 8 pounds each, lol.)

 

As for that crankshaft that you pictured, the notches are not for clearancing, but are a by-product of drilling the angled holes into the rod journals. (note mine are drilled in a straight line through the entire crankshaft, that pictured is a great idea.)

 

 

Jerminator,

Please do some research on the topic. PM me and I'll send you some links to do some basic research before trying to come up with a "hypothetical" dream flat plane V8. Nobody out there that I have seen, even in racing realms, uses a 0% counterweight on a flat plane V8 engine configuration. It would rattle to pieces in a short matter of time. Snap crackle pop.

 

If I were to build a N/A flat plane V8 engine, it would be in the 3.9L-4.1L range with a short stroke and about a 93-95mm bore. Aimed for about a 340-380hp range and rev to 8500-9000rpms.

A forced induction version would be around 3.3-3.5 liters. Aimed for the 650-800hp range to be realistic. (100hp per piston is not too heavy for a purpose built engine)

 

Nissan's R92CP with a flat plane V8 was set at about 940hp for races and 1150hp for qualifying. I know there are some pretty crazy videos of its qualifying runs on youtube...

[Gollum]

What I meant is that the notches look like they were put there befor the drilling. But now that I'm looking at it again, they do seem to taper too one side. So they probably are just drilling through the counter weights. Though I gues it might be possible to come at multiple angles for added reduction.

 

One thing that really worries me about the DOHC V8 setups, is that most of them have a fairly small bore size. So unless we're only looking for the 250-300hp range, the engine build would have to be pretty extreme to make good power levels.

 

With a SBF or SBC setup, a 4" piston is standard, and with a 2.5" bore we're still WELL over 4 liters, and 400hp should be easy to come by with the right head/cam/intake combo... as long as you figure out how to get it to rev up to the required RPM without falling apart.

 

To be honest, I've never heard of any pushrod engines OTHER than nascar getting to those 8k rpm levels. How many people produce parts over the counter that would allow performance like that?

[OlderThanMe]

 

One thing that really worries me about the DOHC V8 setups, is that most of them have a fairly small bore size. So unless we're only looking for the 250-300hp range, the engine build would have to be pretty extreme to make good power levels.

 

With a SBF or SBC setup, a 4" piston is standard, and with a 2.5" bore we're still WELL over 4 liters, and 400hp should be easy to come by with the right head/cam/intake combo... as long as you figure out how to get it to rev up to the required RPM without falling apart.

 

To be honest, I've never heard of any pushrod engines OTHER than nascar getting to those 8k rpm levels. How many people produce parts over the counter that would allow performance like that?

 

Well, a VH45 has a 93mm bore stock, which is ~3.66".

There is somebody that has supposedly put a 305 SBC rod and piston into a VH45 with minimal work........

 

The Ferrari 355 flat plane V8 makes ~375hp out of a 3.5 liter N/A dry sumped motor. Its not that Ferrari did anything particularly special there, they just had good planning.

 

Donor motors for naturally aspirated flat plane V8, I think the number one consideration is the ability to rev high and not explode.(valvetrain mostly)

The second consideration is for the head to flow the amount air as not to choke the engine at high RPMs. (near stock or smaller than stock sized ports on a single cam V8 engine)

 

 

The VH45 starts out with a VE of about 92% which isn't bad at all. Stock ports would be fine for a smaller displacement engine at higher RPMs plus their highly aerodynamic design really helps. (necks down a slight amount half way into the cylinder head intake tract)

 

For a rotating assembly/valvetrain package I believe it would cost about $5000 plus engineering costs at ~$75-$100+/hr.

Now if you can think through the whole ordeal and learn all you need to know(Homeschool yourself! read books!!!!!!!) and design the crank, cam profiles, valvetrain stuff, etc... then it may be cheaper, and props to you for the endurance.

[BRAAP]

....

 

To be honest, I've never heard of any pushrod engines OTHER than nascar getting to those 8k rpm levels. How many people produce parts over the counter that would allow performance like that?

 

 

I have “heard” that some of the faster drag V-8s as far back as the ‘70’s will hit 10,000 RPM. Current Pro stock V-8 engines are shifting between 9000-9300 and read on one site that some Pro Stock engines will spin as much as 9800 RPM. Top Fuel 8200 RPM. Of course these drag engines are only seeing these RPM’s for a very brief second or two max.

[Jerminator96]

Jerminator,

Please do some research on the topic. PM me and I'll send you some links to do some basic research before trying to come up with a "hypothetical" dream flat plane V8. Nobody out there that I have seen, even in racing realms, uses a 0% counterweight on a flat plane V8 engine configuration. It would rattle to pieces in a short matter of time. Snap crackle pop.

 

If I were to build a N/A flat plane V8 engine, it would be in the 3.9L-4.1L range with a short stroke and about a 93-95mm bore. Aimed for about a 340-380hp range and rev to 8500-9000rpms.

A forced induction version would be around 3.3-3.5 liters. Aimed for the 650-800hp range to be realistic. (100hp per piston is not too heavy for a purpose built engine)

 

Nissan's R92CP with a flat plane V8 was set at about 940hp for races and 1150hp for qualifying. I know there are some pretty crazy videos of its qualifying runs on youtube...

 

Hey what happened to not arguing about counterweights anymore? You must have missed the part where I said I was certainly never going to design a 0% crank. Though I guess for the sake of continuing this argument, as you seem to want to, I should say that I could successfully design one. No I am not a crank designer, just an engineer.What was the displacement of that Nissan engine? N/A?Gollum: If my old redneck of an uncle can build a 350 that runs at 9000rpm for his dirt track car then you can certainly do it. Crower, Jesel, Isky, and Ferrea should have everything you need.

[BRAAP]

Pretty sure is not definite. Please memorize the entire thread before you post.

 

 

 

Bones,

Yeeup, you’re absolutely right. “Pretty sure” is not a definite.

 

So I was just sitting here and I started recalling the various posts in this thread, from memory mind you, and feel I have compiled a mostly thorough list of posts that do definitely address the V-8 valve train as used in a high RPM application, or at least make mention of it. My memory is not what it used to be, I may have missed a few posts.

 

 

Page 6, post #118, mentioned in #119.

Page 7, post #125, #128, #130, #134, #139.

Page 8, post #141, #148.

and just recently, Page 22, post #421.