Inline 6 Vs V6 Discussion

[MR2]

I've always felt that the V6 engine was a better design than the inline due to less weight, quite a few of the local guys seem fairly jealous of the 3000gt having a V based engine vs the heavy RB26DETT's in their skylines, yet in chat people are saying otherwise...

DISCUSS!

For comparisons sake, the 6g7x weights

block 43-50kg
crank 20kg
heads 16kg
girdle 6kg

assume we add another 50kg of accessories/brackets/hardware we're talking about 150kg ish?

[mehrshadvr4]

our engine is not really light though. not sure what inline 6s weight. inline is too long and too tall so not good for road racing.

[1990AWD]

The best part of inline is the strength of the bottom end, having a larger crank and more importantly, more journals. Yes, a V-6 maybe is more compact and lighter, but an inline will always be stronger.

[IPD]

the benefit to an inline is that it will theoretically make more power than a v6 of the same displacement. that, and it is naturally balanced internally. you could argue that it also benefits from having only one set of heads.

on the other hand, the benefit to a v6 is that it can be mounted transverse or longitudinally. this also means that weight distribution can be better, because the bulk of the weight can be placed between the wheelbase, rather than in front of it (which tends to be the case with cars that have 5+ cylinders in line (viper, supra, etc). 60-degree v6's are also very good at reducing vibration--and while not perfect, they certainly provide an acceptable compromise.

v's are inherently better suited for twin-turbo applications, and i's better suited for singles. running a dual-exhaust off an i is rather silly (i'd argue even more silly than a true dual-exhaust off a transverse engine).

inline 6's work best when mounted at an angle, which helps lower the center of gravity. in any event though, car manufacturers have all but stopped making inline 6's. even the skyline is now a v-type engine. if inline 6's were substantially better, i don't think that would be the case. i'm guessing this partly has to do with the overlap of technology/engineering between v8's and v6's--just look at GM's vortec v6's.

[j2k4]

I think for this argument to be properly inclusive you have to consider the boxer, which design I believe is inherently best relative to vibration, and while well-suited to rear-mounting, it isn't limited to that.

I was brought up to believe a longer crankshaft will always yield greater instantaneous torque due to the fact it's rotating mass works in greater unity relative to other designs, but forced induction and the various engineering tweaks to timing and valve-action more than offset the few advantages an inline offers.

They also don't like to spin stratospheric RPMs cuz of crank-whip.

[JasonY]

Inline sounds better, is stronger, is cheaper to mod generally. V6 is shorter but in most cars is only used in favor of inline due to packaging since V layout imports are usually fwd derived cars. any DOHC engine is tall as shit, doesnt matter the layout.

Jason

[IPD]

I think for this argument to be properly inclusive you have to consider the boxer, which design I believe is inherently best relative to vibration, and while well-suited to rear-mounting, it isn't limited to that.

I was brought up to believe a longer crankshaft will always yield greater instantaneous torque due to the fact it's rotating mass works in greater unity relative to other designs, but forced induction and the various engineering tweaks to timing and valve-action more than offset the few advantages an inline offers.

They also don't like to spin stratospheric RPMs cuz of crank-whip.

inline 8's would be awesome if that were the case. who makes an inline 8?

radial engines provide more torque than inlines, i'd wager. ;)

[j2k4]

inline 8's would be awesome if that were the case. who makes an inline 8?

radial engines provide more torque than inlines, i'd wager. ;)

Inline 8s were pretty cool; my Pops had several in Buicks he owned.

Tons of torque, but the same problems emerged; size/usage limits, they didn't pull revs, and the advantage of 'instantaneous torque' only translated to a really good 10-foot time. :)

As to radials:

http://www.autoblog.com/2013/01/10/prop-driven-vw-beetle-hopes-to-land-in-bonneville-w-video/

Don't believe I've ever seen a radial/6. :huh:

[mehrshadvr4]

inline 8's would be awesome if that were the case. who makes an inline 8?

radial engines provide more torque than inlines, i'd wager. ;)

inline 8 is a terrible design. 90 degree is the best for v8 because of no vibration.

[donniekak]

A v6 only has 4 mains, not a very strong design. Inline 4, and v8 hav 5, and inline 6 has 7.

[IPD]

A v6 only has 4 mains, not a very strong design. Inline 4, and v8 hav 5, and inline 6 has 7.

shouldn't matter. torsional forces should (theoretically) be less on a shorter crankshaft.

[mehrshadvr4]

A v6 only has 4 mains, not a very strong design. Inline 4, and v8 hav 5, and inline 6 has 7.

What do you mean not very strong? GTR has v6 and it made 1600whp on aluminum block. the strength is actually in to materials and block design. yes there is more surface bearing on crank which can help with less bearing wear but also more friction, but with very good oiling system which would work the same on any engine you can make a v6 very reliable or inline 6 unreliable if you don't have good oiling system. inline engines have room issue so they can't be made from thick casting so the cylinder walls are not as thick and also they can't be made with large valves because they design them to be as short as possible. in results smaller pistons and smaller valves and less flowing cylinder heads. don't look at 2jz. other inline 6s came no where near 2jz engine. I can grantee you our block is way stronger than any other gas inline 6 engine out there. looking at the block you can see how mitsubishi strength the block from top and sides. it looks like a diesel engine block. we just need someone who can push it to the max after finding a solution to keep the heads seal which i think i did. Saf is going to try this on his car soon. most 2jzs are actually half filled when reaching over 1300-1400whp. Nelson't car is making easy 1300whp if it was on rwd car and the block is not even sweating. rb engines can crack cylinder wall if push pass 1100 1200 hp.

[donniekak]

The blocks in these cars were originally developed as 150hp minivan engines. The center 2 mains each feed 2 rods, and a port for the a cylinder head. A real performance design has what's called priority main oiling, where the crank is fed first, and the cylinder heads afterward. The fact that Mitsubishi put such small restrictors in the galley to feed a 12 valve dohc cylinder head is proof they knew the oiling system was a problem. No wonder why the lifters tick. All the oil in the head has to pass through this.
http://i408.photobucket.com/albums/pp170/donniekak/IMAG0039.jpg (http://s408.photobucket.com/user/donniekak/media/IMAG0039.jpg.html)

[mb7050]

debonair is not a minivan

[mehrshadvr4]

You should know it better the tt engines have nothing in common as other 6g engines specially the sohc block. also they put restrictors there because cylinder heads don't need as much oil. rb26 people put even smaller orifice restrictors for the head to reduce oil flow to the head to keep oil down in the block and have less oil drainage problem.almost all engines come with that. as far as center main feeding two rods it's same in any other v or w engines. v8,v12,v16,w16,w12,w8 all use the same concept.if the engine is design right they will give it enough volume to feed two rods. priority main oiling is on all cars even ours and since the heads have restrictors there is a very small effect on main bearings.looking at this ohv v8 should have the worse oiling system then and it's priority main oiling like any ohv engines. look the mains have to feed two rods and cam shaft and the heads at the same time. ours there is small hole on front and back to bleed some oil to feed the heads. if the orifice is too big this cause oil pressure drop and too much oil goes in to head (like rb26) and it'll drain the mains and oil pan (like rb26).
http://www.supermotors.net/getfile/798026/fullsize/clevoilsketchjpg.jpg
I watched the 80s turbo engine built and they feed the heads just like our car. from the center of oil gallery, but it was external fed because of making casting and such simpler.

[donniekak]

Well, I've been proven wrong. Old v8s spun rods like nothing, and 6g72 dohc engines have no issues with wiped center mains and spun rods.
The crank in a 91-92 vr4 is the same crankshaft that was in millions of 80's minivans. Mitsu bolted dohc cam heads, and 2 turbos on them. Should have worked out fine right?

[mehrshadvr4]

That's where the issue was. putting cast and weak crank on turbo cars. I think even the 4 bolt blocks have weak crank and also the oil pump is not good enough for the engine. I would love to see the oil flow comparison between na and tt oil pump. I bet the is little to no difference between the two and TT oil pump has to pump oil to two turbos and oil jets right where the mains are and oil cooler. In my built i'm going to block the turbo oil feed lines on the oil pump and get the oil from the head where they are already done lubing the bearings and i'll also block the oil jets. this should improve the oil flow to the bearings. people right now have much more reliable engines with stronger crank also.

[ilian51378]

The blocks in these cars were originally developed as 150hp minivan engines. The center 2 mains each feed 2 rods, and a port for the a cylinder head. A real performance design has what's called priority main oiling, where the crank is fed first, and the cylinder heads afterward. The fact that Mitsubishi put such small restrictors in the galley to feed a 12 valve dohc cylinder head is proof they knew the oiling system was a problem. No wonder why the lifters tick. All the oil in the head has to pass through this.
http://i408.photobucket.com/albums/pp170/donniekak/IMAG0039.jpg (http://s408.photobucket.com/user/donniekak/media/IMAG0039.jpg.html)

I will need to remove the heads in order to replace those, won't I? I installed a rebuilt engine in my car and immediately noticed that the oil pressure was lower than before... Then I researched and discovered that it is rather typical for machine shops to remove those when skimming heads and they never get installed back after that. That is why a number of people observe a low oil pressure after rebuilding their heads... I am so upset that it drives me crazy! How bad is it to drive the car without the orifices and how long would it take before it csuses serious damage?

[NOMIEZVR4]

2jz is an inline 6. 2jz is also God's gift to boost junkies/enthusiasts

2jz > all other 6 cylinder motors

Therefore...

Inline 6 > v6

[NOMIEZVR4]

That's where the issue was. putting cast and weak crank on turbo cars. I think even the 4 bolt blocks have weak crank and also the oil pump is not good enough for the engine. I would love to see the oil flow comparison between na and tt oil pump. I bet the is little to no difference between the two and TT oil pump has to pump oil to two turbos and oil jets right where the mains are and oil cooler. In my built i'm going to block the turbo oil feed lines on the oil pump and get the oil from the head where they are already done lubing the bearings and i'll also block the oil jets. this should improve the oil flow to the bearings. people right now have much more reliable engines with stronger crank also.

I've never such an advocate for the 6g72 like you...:p Do you have 6g72 posters on your bedroom wall?..:D

[IPD]

Why revive this? V6 = better packaging. I6 = "better" performance. 'nuff said.

[CoopKill]

I will need to remove the heads in order to replace those, won't I? I installed a rebuilt engine in my car and immediately noticed that the oil pressure was lower than before... Then I researched and discovered that it is rather typical for machine shops to remove those when skimming heads and they never get installed back after that. That is why a number of people observe a low oil pressure after rebuilding their heads... I am so upset that it drives me crazy! How bad is it to drive the car without the orifices and how long would it take before it csuses serious damage?


The blocks in these cars were originally developed as 150hp minivan engines. The center 2 mains each feed 2 rods, and a port for the a cylinder head. A real performance design has what's called priority main oiling, where the crank is fed first, and the cylinder heads afterward. The fact that Mitsubishi put such small restrictors in the galley to feed a 12 valve dohc cylinder head is proof they knew the oiling system was a problem. No wonder why the lifters tick. All the oil in the head has to pass through this.
http://i408.photobucket.com/albums/pp170/donniekak/IMAG0039.jpg (http://s408.photobucket.com/user/donniekak/media/IMAG0039.jpg.html)
Where exactly are those. Is there a pic in the manual? I need to check to see that they were replaced as well. Unfortunatly I just reinstalled the engine...

[familyMAN]

http://i11.photobucket.com/albums/a199/fr11day/IMG_0123.jpg

Bottom side, between the right two cylinders. The spot that's leaking oil.

[sergechronos]

http://i11.photobucket.com/albums/a199/fr11day/IMG_0123.jpg

Bottom side, between the right two cylinders. The spot that's leaking oil.

That's not an oil leak..That's sweat from all that horse power.. :suspect:

[jerrid]

Well I'm a fan of the barra ford i6 we never got here in the us. 4.0 dohc fpv is 420hp @5500 420tq @2000. But that engine is 35" long

Sent from my DROID RAZR using Tapatalk

[ilian51378]

So, how bad is it to drive the car without the oil restrictors? Will my engine last less then with the restrictors? I am going to install them when I swap my pistons for low compression ones. I will also install new bearings, just in case. By the way, I am thinking about installing one of those multi-layered metal head gaskets, because people keep telling me they are better than the graphite ones. Is that true?

[sergechronos]

So, how bad is it to drive the car without the oil restrictors? Will my engine last less then with the restrictors? I am going to install them when I swap my pistons for low compression ones. I will also install new bearings, just in case. By the way, I am thinking about installing one of those multi-layered metal head gaskets, because people keep telling me they are better than the graphite ones. Is that true?

Without the restrictors more oil ends up in your head than it actually needs. I'm not sure on the long term ramifications of it, but I wouldn't want to drive it much like that.

Yes you should go MLS on the head gaskets, go OEM MLS head gaskets and bolts. They've been proven to hold up better than just about anything else out there for us.

[ilian51378]

Without the restrictors more oil ends up in your head than it actually needs. I'm not sure on the long term ramifications of it, but I wouldn't want to drive it much like that.

Yes you should go MLS on the head gaskets, go OEM MLS head gaskets and bolts. They've been proven to hold up better than just about anything else out there for us.

I actually read that since more oil stays up in the heads, the bottom end is starved for oil and thus the life of the engine will probably be shortened... I can't understand how someone who is a mechanic would assemble a rebuilt engine and not make sure that the restrictors have been reinstalled... It happened twice with me. I had the heads rebuilt on my first 3/S and after I got the car back, I immediately noticed that the oil pressure was lower than before the rebuild. The same happened with my current 3/S, after I bought a rebuilt engine from a place that specializes in engine rebuilds... It makes me sick when I think about how I am expected to be perfect at my work place, but I don't get close to the same from other places when I am the customer.

[ilian51378]

Here is where I got the info about the oil restrictors from:

Cylinder Head Oil Restrictor (http://www.e30m3project.com/e30m3performance/installs/2.5_rebuild/restrictor/restrictor.htm)