VQ37 VHR NA rebuild suggestions.
 

I am getting ready to (re)build my Z's tired engine. Initially, I was doing the timing chain because there was a timing issue that popped up. Come to find out the chain actually jumped timing at the head due to very badly lubricated, under lubricated tensioner. I married into this car so I will spare the ugliness of Z neglect and just tell you the deeper I got into the timing cover and valve covers the worse it started to look. Crappy oil, irregular oil changes, failure to ID the oil consumption TSB on this motor all contributed to early retirement.

So it's in my friend's shop and we are contemplating the build and preparing for the overhaul now. I want to keep the engine NA, but want the short block upgraded to Stage 1. I don't know much about this engine. What other upgrades would you consider for a solid long block that will be rock solid reliable, long life (with proper and regular care), and maybe a few extra horsepower. This is a daily driver and I don't want to spend a fortune building a super street car.

Do I need to upgrade the oil delivery system? Sump? Do I need an oil cooler? What are the weak points on this engine that have aftermarket solutions?

Any help would be great. I am still researching this site and others for the answers. Any suggestions would be considered.

Nice to see a fellow Z enthusiast doing a engine rebuild before engine failure. What year is your Z? How many miles do you currently have? Your rebuild will depend on what your budget is? Instead of using your current VQ37HR and rebuilding with a rotating assembly I would opted for installing a new long block it's your Z you have to live with it. If you are just looking for a reliable engine you can use for street duty I recommend the AAM Competition stage 1 long block very nice engine for what you are paying for with upgrade options just an idea and will be better. Think before you purchase a used engine could be hit or miss. The oiling system on the Z is quite sensitive actually. Using the correct motor oil could be detrimental to the engine. I recommend running a quality synthetic motor oil. Oil pump failure happens more often on our cars than you may think and is a weak point on our cars. When you do your rebuild seriously consider installing upgraded Boundary Engineering billet oil pump gears it's a good investment in your engine and is well worth doing. Definitely install an aftermarket engine oil cooler the "bandaid engine oil cooler" isn't the best. I believe every Z should have a oil cooler it will add life to your engine. If your Z has a manual transmission install the Z Speed CMAK because the Genuine Nissan CSC will fail it's a question of when will it fail not will it fail? There are some small NA performance upgrades you can do on your rebuild. I would consider installing a better flowing exhaust system and HFC's or test pipes would be on my list but be careful since you are in CA. Best option is to spend the time searching this wonderful forum there is a large wealth of knowledge here.

Stay from AAM anything :wtf2:

OEM engine block is fairly stout. Proper rebuild should last a while with proper maintenance. For street car, you won't need too much in the way of engine upgrades, but you have a variety of options if you want to beef it up a bit depending on your budget.

Get the EPS oil gallery gasket and hardware kit. Oil pump gears are a known weak point but really only at sustained high RPMs, which shouldn't be a problem on the street.

Thanks Q. The engine/vehicle is 2010 (has the oil over consumption problem) and made it 110,000 miles until it quit. Oil sludge, excessive wear, and burn scars on all valve train and timing chain components.

Original automatic transmission. (Will it need rebuilding, what can be done now).

Can I do a short block and re-use the factory bolt on parts after they've been cleaned and re conditioned? I know that is also money and time and possibly not a good return on investment. Trying to save $$ as well. :ugh:

Are you suggesting sending the block out to a machine shop for reconditioning? I have a call into a local shop but haven't heard back. I would like to keep same compression ratio but upgrade rings and pistons, possibly have the crank worked up.

I know the slippery slope of engine mods well.... it becomes an obsession! ;)

Why would you send it out when you have it at a friend's shop? Can y'all not do the reconditioning and rebuild there?

There's really no reason to upgrade rings or pistons for a street car. Several guys are running 500+ hp on the stock block for years now (100K+ miles) without issue.

If you want to upgrade the block, it won't hurt anything but your wallet. It's your car, so do what you want.

No the shop is really limited to remove and replace type work. No machine equipment beyond lifts, hand tools and some parts cleaner stations not big enough to handle a block. No hot bath. Otherwise I might go for it :tup:

I thought the stock rings and pistons were the source of the oil over consumption problem outlined in the TSB?

The main contributors that plagued the 2009 and 2010 with the excessive engine oil consumption TSB was mainly the piston rings and valve stem seals. Pistons and rods contributed to the issue I was told by a Nissan tech and they were simply replacing the engine with a brand new long block. If your resources are limited where you are then your best option may be to install a new short block sounds like you are on a limited budget NA will get expensive quickly. I know of quite a few fellow Z enthusiasts that are running 500-600 hp with no issues but their engines are low mileage in excellent health. Any stage 1 short block or even a Genuine Nissan OEM short block will work fine for a street car. Either way you will be rebuilding the rest of the engine.Overall comparing with other vehicles the VQ37HR is actually a very stout reliable engine when the owner is doing all the maintenance on time. I would definitely install a new oil pump and water pump. The oil pump gear upgrade is a excellent investment even on a street driven Z the last you will want to do is have to go through the engine again for a second time. The EPS oil gallery gasket and hardware kit is well worth it I honestly would not skimp there as my oil gallery gasket leaked before and yes it was no fun replacing it. Address the engine first with a rebuild and then consider doing your transmission and rear end later if they are working properly and have no issues. If you have a 7AT then I would do a transmission fluid flush while you are in there. Also there is no need to upgrade your pistons and rods if all you are planing on using your Z is for street duty. It's your Z and you will have to do your research and shopping good luck with your rebuild I had no help doing my engine rebuild.

It is inevitable you will have to rebuild your current cylinder heads or purchase new cylinder heads since oil is probably making it past the valve guides. There are plenty of reputable vendors out there to help you with the cylinder heads.

excellent thank you Q. I have some calls in to some machine shops in northern and southern california. Everyone is super busy right now. I will try and get the block and heads reconditioned and stay with (mostly) OEM parts. I will be sure to take many pictures along the way so when it's done I can create a basic rebuild thread for those who want to do this on their own.

Regards,

I don't know how far you want to go with bolt-on performance upgrades, but if you want to do cams or headers, definitely get it done now while you have the motor out. Maybe do test pipes / HFCs too (they're one of the best bang for buck mods)

I'd say if its a street car just keep it as stock as possible engine wise. but for sure do cams and upgraded oil gallery gasket. anything that's an upgrade and you may notice on the street is worth it.

here is the left side overhead view of the intake and exhaust camshafts.

You shouldn't be allowed to own a car. :icon14:

He said he married into the car in his op so I don't think he was the one that neglected it.