DOHC heads on LSx from a Nissan Titan...read
01-26-2011, 05:47 PM
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DOHC heads on LSx from a Nissan Titan...read Found this article and was thinking if anyone has tried this or had the means to try...
-Garrett
http://www.hotrod.com/techarticles/e...der_heads.html
The chamber spacing on a Nissan DOHC head off an Infiniti or Titan V8 is within 0.009 inch of a Chevy small-block (both classic and LS). It may fit the LS even better because both have four head bolts/cylinder. Most engines tolerate a 0.010- to 0.020-inch misalignment, but to end up dead on, offset-bore the block.
-Garrett
http://www.hotrod.com/techarticles/e...der_heads.html
Exotic Heads
Pete Aardema specializes in what could be the ultimate dare to be different, street-driven head conversion: changing American domestic pushrod engines to overhead cam configurations. The two main approaches used by Aardema: for single overhead cam (SOHC) conversions, fabricating a custom cam box that bolts to the existing pushrod-type head; for dual overhead cam (DOHC) changeovers, bolting on a DOHC head from a foreign engine.
For a DOHC conversion, the idea is to adapt a head from an engine family that has similar cylinder bore spacing to the pushrod engine you're working on. A Nissan Infiniti V8 is close to a small-block Chevy; a six-cylinder Subaru, a 4.3L Chevy 90-degree V6; a V8 Porsche, a big-block Chevy. Scope out swap possibilities by comparing head gaskets from different engines. It helps if the head bolt patterns are similar, but don't be afraid to plug and redrill head bolt and coolant holes in the block. Aftermarket blocks (say, from Dart) can be ordered with an undrilled blank deck and the bore centers only roughed in. Cometic can make custom head gaskets to order.
Paxton offers a universal... read full captionPaxton offers a universal airbox assembly for carbs, as on this small-block Mopar kit. A new, more compact, round airbox is also offered. The airbox plus aircraft-style flexible ducting (sold by Aircraft Spruce) could be used to fab a kit for a niche motor. Aircraft Spruce also sells aluminum plate to make custom mounting brackets.Provisions must be made to supply oil to the new head and block off the old, now-unneeded passages. This may require lifter-bore plugs-either completely blank (fabricate external oil lines), drilled to supply necessary internal oil to the top end, or so modified to keep the bottom end alive.
Most modern DOHC mills are beltdriven. You can often adapt or modify the original drive pulleys with custom idlers and different-length belts, or use a Gilmore setup with cogged pulleys. ASP is one source for special pulleys. Custom cams are available for any application these days, although they may need to be made from billet steel. And yes, Aardema is willing to offer advice and assistance to those attempting similar conversions.
Pete Aardema specializes in what could be the ultimate dare to be different, street-driven head conversion: changing American domestic pushrod engines to overhead cam configurations. The two main approaches used by Aardema: for single overhead cam (SOHC) conversions, fabricating a custom cam box that bolts to the existing pushrod-type head; for dual overhead cam (DOHC) changeovers, bolting on a DOHC head from a foreign engine.
For a DOHC conversion, the idea is to adapt a head from an engine family that has similar cylinder bore spacing to the pushrod engine you're working on. A Nissan Infiniti V8 is close to a small-block Chevy; a six-cylinder Subaru, a 4.3L Chevy 90-degree V6; a V8 Porsche, a big-block Chevy. Scope out swap possibilities by comparing head gaskets from different engines. It helps if the head bolt patterns are similar, but don't be afraid to plug and redrill head bolt and coolant holes in the block. Aftermarket blocks (say, from Dart) can be ordered with an undrilled blank deck and the bore centers only roughed in. Cometic can make custom head gaskets to order.
Paxton offers a universal... read full captionPaxton offers a universal airbox assembly for carbs, as on this small-block Mopar kit. A new, more compact, round airbox is also offered. The airbox plus aircraft-style flexible ducting (sold by Aircraft Spruce) could be used to fab a kit for a niche motor. Aircraft Spruce also sells aluminum plate to make custom mounting brackets.Provisions must be made to supply oil to the new head and block off the old, now-unneeded passages. This may require lifter-bore plugs-either completely blank (fabricate external oil lines), drilled to supply necessary internal oil to the top end, or so modified to keep the bottom end alive.
Most modern DOHC mills are beltdriven. You can often adapt or modify the original drive pulleys with custom idlers and different-length belts, or use a Gilmore setup with cogged pulleys. ASP is one source for special pulleys. Custom cams are available for any application these days, although they may need to be made from billet steel. And yes, Aardema is willing to offer advice and assistance to those attempting similar conversions.
The chamber spacing on a Nissan DOHC head off an Infiniti or Titan V8 is within 0.009 inch of a Chevy small-block (both classic and LS). It may fit the LS even better because both have four head bolts/cylinder. Most engines tolerate a 0.010- to 0.020-inch misalignment, but to end up dead on, offset-bore the block.
01-26-2011, 10:46 PM
#3
prolly more work to just use heads that flow significantly less than stock or a ported stock ohv 2v casting. and make cam install much more complicated. is it different? sure. better. nah!
more work for less imo.
unless a stock nissan head outflows a portedor stock 243 which just bolts on. which i serioulsy doubt.
i just dont see the point
more work for less imo.
unless a stock nissan head outflows a portedor stock 243 which just bolts on. which i serioulsy doubt.
i just dont see the point
01-26-2011, 11:03 PM
#5
Folks get way too hung up on the overhead cam thing. If it added a lot of power or fuel mileage...but it does not and is more complex and expensive to produce and repair. It is heavier also.
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01-27-2011, 06:58 AM
#8
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Agreed.
And folks here think camming a ls is expensive. Try buying 4 sticks for 1engine. Jim Wolf sells them at around 300 per stick. ( and get about 25whp.)
Who knows what they would run for a custom aplication.
Being a former Nissan nut, this was a cool read with the question being why?
Thanks!
And folks here think camming a ls is expensive. Try buying 4 sticks for 1engine. Jim Wolf sells them at around 300 per stick. ( and get about 25whp.)
Who knows what they would run for a custom aplication.
Being a former Nissan nut, this was a cool read with the question being why?
Thanks!
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01-27-2011, 10:23 AM
#14
I see no benefit to this at all.
As everyone else stated, whats the point??
Will is make more power?? Unlikely. Better fuel economy or driveability?? Even more unlikely. About the only thing it can do is turn higher RPM's, which is pointless if you're making less power overall and losing low end power and torque.
If you want a DOHC engine, build a Ford Aluminator - 5.4 DOHC, fully built for whatever you want to throw at it. If you want to build an LSX, stick with what the engine was designed for - OHV 2V heads that can move massive amounts of air.
As everyone else stated, whats the point??
Will is make more power?? Unlikely. Better fuel economy or driveability?? Even more unlikely. About the only thing it can do is turn higher RPM's, which is pointless if you're making less power overall and losing low end power and torque.
If you want a DOHC engine, build a Ford Aluminator - 5.4 DOHC, fully built for whatever you want to throw at it. If you want to build an LSX, stick with what the engine was designed for - OHV 2V heads that can move massive amounts of air.
01-27-2011, 10:44 AM
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Nelson racing engines has already developed one. I watched a video of his block heads and crank he designed for dohc. It will finally do away with the dohc argument.
dont think its going to net much gain. Remember you may get rid or pushrod weight, however your replacing that with 4 cams, twice as many valve springs working against your motor. Setting up the valve lash is twice as much work.
I guess you could turn the middle of the engine into a neat cooler for your chosen beverages, im guessing the import market would like that.
However cam-ing your ride would be rather pricey. I never thought of that before. Good point whoever mentioned that one.
dont think its going to net much gain. Remember you may get rid or pushrod weight, however your replacing that with 4 cams, twice as many valve springs working against your motor. Setting up the valve lash is twice as much work.
I guess you could turn the middle of the engine into a neat cooler for your chosen beverages, im guessing the import market would like that.
However cam-ing your ride would be rather pricey. I never thought of that before. Good point whoever mentioned that one.
01-28-2011, 02:35 PM
#19
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i.e. even with each pushrod operating two valves, the 4 ports take up all the room where the pushrods would be passing thru the head.
