Nissan VQ Engine Valve Cover Bolt

There are diffrence of design for the engine manufacturer on how to fastern the valve cover gasket to the valve cover on an engine.

Some using traditional type of bolt and nut, but there are quite a number of the design is using valve cover bolt, (some may call it valve cover seal or valve cover bush).

The picture show the type of vlave cover bolt that use on Nissan Cefiro V6 engine, which is in the VQ series engine type. This may applicable for Nissan Teana, Murano and Elgrand.

Korean Car with Japan Engine?

It is known that in the early day, quite a number of Korean passenger car is using the Japan made engine, such as the old model of Hyundai Sonata use dffrent type of Mitsubishi 4G63 engine, Kia Sephia is using Mazda B6-D type of engine, and old model of Kia Sportage is using Mazda FE type of engine.


With the improving of automotive technologies in Korea, their research team start to design their own engine, but most of them still modified from the existing type of Japan engine, they might modified the Valve Cover design, or design in Intake and Exhaust area.


Please find the article below from http://www.paultan.org/ which introduce the newly launch Naza Rondo 7 seater SUV, which have some interesting point in their engine specification.

Naza Kia Sdn Bhd has launched the new Naza Citra II Rondo in Malaysia. The Naza Citra II Rondo is essentially the Kia Rondo which is the replacement model for Carens that the Naza Citra is based on. The Citra will continue to be sold as a budget 7-seater SUV, and the new Naza Citra II Rondo will be positioned between the Citra and the Ria, bringing Naza Kia's 7-seater offerings up to 3 models.

According to Naza Kia, the new Rondo is built on the D-segment new Kia Optima platform and also share the Optima's sweet new GEMA-based 2.0 liter DOHC CVVT engine producing 145 horsepower and 189Nm of torque, mated to a 4-speed automatic transmission with sequantial manual shifting. The GEMA engine is a joint project between Daimler Chrysler, Hyundai and Mitsubishi. The 4B11 in the Mitsubishi Lancer is also based on the GEMA family.

NISSAN VQ ENGINE PLUG SEAL

Nissan VQ type of V6 engine have quite a difference characteristic with those Mitsubishi or other type of V6 engine. For Mitsubishi type of V6 engine (e.g. 6A1X or 6G7X), the engine gasket for both left hand side and right hand side are design as the same item, but for Nissan type of V6 engine, most of them are difference part for left and right.

It is known that Cylinder Head Gasket, Rocker Cover Gasket are difference for left side and right side for VQ engine, but do you thing the Plug Tube Seal for this type of engine have the difference parts for left and right side?

6 pieces of Plug Tube Seal are used for one engine which consist 3 pieces a side, and this Plug Tube Seals are not packed in Genuine Full Set or Head Set gasket, the question is are they using 6 pieces same items or 3 pieces a side with 2 difference parts?

There are 2 type of Plug Tube Seal are applicable for VQ Engine, which is 13276-31U21 and 13276-31U10 (Please refer to the photo diagram).

Parts catalog shows that both items are interchangeable although their size may have slightly difference, and 6 pieces of each part number per engine are usable.

But it seem there are foreman claim that 3 pieces of each part number are use for the left hand and right hand side. This info is quite confusing and we wish for those is expert in this Nissan VQ engine are welcome to comment on their view for this scenario.

Range of VQ35DE Engine Gasket

We may start to know the existing of Nissan VQ35DE engine after the Murano 3.5 V6 is entering Malaysia, but the earlier type of VQ35DE vehicle that already driving on Malaysia soil is the luxury van of Nissan Elgrand.

In Japan, there are also Terrano 3.5 that using VQ35DE engine, the other type vehicle may be Maxima.

Although the engine specification is all putting as VQ35DE, they may be have some slight modification on the Cylinder Head Gasket and Rocker Cover Gasket for diffrence vehicle, hence before buying any VQ35DE gasket set, it is better to check the exact part number for their Cylinder Head Gasket and Rocker Cover Gasket to prevent of wrong purchase.

Also don't be confuse of this type of engine with VQ35HR which mainly use on Nissan 350Z Fairlady sport car.

VQ35DE ENGINE PARTS

HIGH COMPRESSION RATIO CYLINDER HEAD (Source: http://www.nismo.co.jp/en/products/competition/engine/vq35de.html)





Features

A version 2 model, applicable to exhaust side VTC.To meet modifications to inlet valve seat internal diameters and ports, two versions Spec-1, diameter 31 and Spec-2, diameter 32-was created.

Easy increase of compression ratio

Compared to a genuine VQ35 head, the combustion chambers of the genuine VQ30 are used as the base for casting a processing, providing the compact combustion chamber required by an NA engine. The volume has been greatly reduced. With the combustion chamber volume reduced from 56cc to 46cc, the compression ratio is increased without head milling (using a genuine piston, from 10.3 to 12.0). In addition, by changing the piston crown shape, a compression ratio of 13.5 is also possible.


Easy increase of intake port potential

While this head uses the dynamic valve system of the VQ30 engine, the intake port uses the high-potential port used in the VQ35. Spec-2 uses an intake valve seat diameter of 32 to modify the intake port inside R to realize performance that greatly exceeds that of a genuine VQ35 engine (please see the table at the VQ35 Intake Port performance comparison).
* The VQ35DE engine is a V6 engine using VTC. Do not use simple milling of the head to reduce combustion chamber volume.





Spec-1 secondary spec

Shape comparison, NISMO and genuine parts

Combustion chamber, Spec-1 secondary spec

Combustion chamber, genuine

Compared to genuine metal gaskets, the use of molybdenum coating helps withstand higher compression ratios and improves surface pressure around the bore.

The VQ35DE Metal Head Gaskets are 0.7mm thick and feature a 4-layer stopper-type structure. The stopper-type structure employs a stopper ring around each combustion chamber that is molded into the head gasket for a precise and strengthened seal. The factory head gasket is only made from 3 layers and has a bead-type structure. A bead-type head gasket only uses a raised bead to seal the combustion chamber.

Japan Motor Vehicles Guidebook

For those who very like to study the latest trend of Japan car and motorcylce, the Japan Motor Vehicles Guidebook is a very good "dictionary" for the Japan car lover.

This guidebook which issue annually already reach vol. 55 for this year, as this book showcase all the latest Japan vehicle currently available in Japan market, though some of the model may not available in Malaysia, in our previous experience, some of the new model bringing into Malaysia may be already shown in the previous guidebook, may be 3 to 4 years ago, so in this current issue, we may see in the future 2 to 3 years, there will be some of the model show in this vol. 55 guidebook will appear in Malaysia.

Basically, the content of the guidebook have the latest technologies news, motor parade, latest model news and most important information in their catalog part, which also devided to Passenger Cars, Commercial Vehicles and Motorcycles.

Head Gasket Basics

Sealing the Deal for Maximum Compression -

Understanding why a relatively inexpensive head gasket costs so much to replace means first realizing what it sits between. In the engine block are pistons that travel up and down in cylinder bores. The pistons are connected to rods, which in turn are connected to a spinning crankshaft from which the vehicle takes its power. Bolted to the top of the engine is the cylinder head. Inside the cylinder head are valves that open and close to let air and fuel into the cylinders and expel the spent exhaust gas.

The head gasket is compressed between the engine block and the cylinder head. The head gasket seals in the internal combustion process and also keeps coolant and oil from mixing together as the two fluids travel from the engine block to the cylinder head. Head gaskets themselves are not very expensive. What ends up costing big money is getting to it. Removing and replacing the head gasket means undertaking the major operation of removing an engine's head.

Boiling Over
A head gasket can fail for a number of reasons, none of them good. Engine overheating is the most popular culprit. The metal of the engine block and head expands beyond limits during overheating. This expansion can pinch the head gasket to the point where it will fail. The next major causes of head gasket failure are engine pre-ignition or detonation. The crux of these two conditions is out-of-time combustion occurring in the cylinders. Internal combustion is supposed to occur with both valves closed and with the piston at the top of its power stroke. Out of time combustion puts extra strain on the valves, pistons, and head gasket. Ironically, engine overheating can also increase the likelihood of pre-ignition and detonation. The sound of an engine pinging or knocking is the insidious sound of damage.

Head Surgery
Head gasket replacement is not a job for the average do-it-yourselfer. While a head gasket expiring due to old age is rare, it usually means everything else is worn out to the point of replacement as well. Cracking the head off the engine and peering inside may reveal that everything else got fully cooked, too. The best way to prevent head gasket failure is to keep the cooling system in top working order and make sure the engine is in tune and running correctly. The failure of a $5 thermostat or $3 coolant hose can cause thousands of dollars in engine damage in a hurry. The following are a few general tips for replacing a head gasket. For vehicle specific head gasket replacement procedures always consult a service manual.

Step 1 - Getting down to the head gasket can be an involved process. Always mark and index everything before removal. In this case, it was easier to remove the exhaust manifold, head, and intake as a unit. A service manual is the first and most important tool in the toolbox.

Step 2 - Check the head and block for flatness. A machined straight edge across the surface and feeler gauge will reveal all. The service manual will provide specifications. Blocks or heads out of specification must be sent out to the machine shop and be repaired. The machine shop will also be able to check for cracks.

Step 3 - Prepare the surface. Never use anything that will remove metal. Be careful not to scratch the deck of the block or mounting surface of the head. While it may seem like a good idea to use a scrubber pad connected to a power tool, the surface irregularities created can cause sealing problems down the road.

Step 4 - Chase the head bolt or stud holes with a tap or thread chaser to remove any crud and prepare the threads. Use compressed air to blow out any stragglers. Correct head bolt torque is of utmost importance. Any interference can throw off the torque readings.

Step 5 - Pre-fit the head gasket in the correct orientation. Never use sealant unless specifically required by the manufacturer. Head gaskets that require sealant will usually come so equipped. The service manual will outline sealant locations and requirements.

Step 6 - Correct bolt tightening sequence and torque is key to proper head gasket sealing. Use new bolts if required. Coat head bolt threads with some engine oil before installing. Always follow tightening sequence and torque instructions to the last detail.