Hi there

Pardon my ignorance but I'm totally new to engine internals and I don't know if this question actually make sense. In order to have peace of mind with FI is it possible to just upgrade the connecting rods keeping stock pistons? I know... since you are there why not upgrade everything else... still I just want to replace the weakest link in this engine (I would also upgrade head gasket and bolts with HR parts) without touching heads, cylinders, crank, etc.
My other question is: can this be done with the engine on the car or it needs to be pulled out?
All the reading that I've done is telling me that there might be something wrong with this idea but still I would like to ask.

Thanks a lot for your time

 

if you're gonna change rods you need to change the pistons also, plus the stock compression is too high and thats not to safe for FI.
you'll need to pull the motor for all this work. its not hard at all to pull the motor and it only takes a couple of hours.

 

Hey there. Feel free to call me at the shop with any questions. We are located in South Florida and have built many VQs. We know our way around them and can answer any questions. Our info is located in my signature.

Thanks!

 

Correct me if I am wrong but I really don't think you would gain anything from using the HR headgasket if it fits and I'm 100% sure that the head bolts will not work. Stock compression is not too high that's how there is a stock block HR putting out 5xxwhp stock block and the G37 making 611whp stock block. Of course the right tune is extremely vital with those applications. Also race fuel I'd say at that point is a must.

 

hey there. Feel free to call me at the shop with any questions. We are located in South Florida and have built many VQs. We know our way around them and can answer any questions. Our info is located in my signature.

Thanks!
__________________


Thumbs up for someone actually trying to help

 

it can't be done with the engine in the car, and with the level of disassembly you have to get to in order to replace the rods might as well do the rest of the build, bu if you want to save the cost of the pistons it can be done but you will still have the cost of the balance, bearing check/selection, might as well replace piston rings to open the gap a bit......... basically you will have most of the cost so why not spend another 600.00 bucks and get pistons which will make it even safer and reduce the compression and you are set for high boost.

 

ok, I'm getting it. Definitely the engine have to be pull out. Now, if I use low compression new pistons, do I have to bore the cylinders or there is rings that fits without machining?

About the latest HR head gaskets and bolts. I read a whole thread about it and everyone recomend them. Did I read wrong?

Thanks

 

how many miles on your motor?

Best to have a machine shop inspect the block and at least hone the bores (may not need to bore them out). Will add a couple weeks to the build time waiting on pistons, but worth it in my opinion.

tom

 

IMO.....If you are going for up to 600whp DD...I see no problem with the HR bolts and gaskets.....Thats what the Mad Scientist uses and I think he is over 680. Like I said ...IMO...if it was my car I would use HKS/L19 if I was going for bigger power.

You are in Florida....go vist CoachK/JT at "UP" ..... They will walk you through the entire process which will save you headaches in the end.

 

Interesting reading of a stock VQ FI'd that eventually failed and why, even though sounds like OP is going for a build and wise decision imo.

http://www.modified.com/tech/sccp_08...5de/index.html

I found interesting the weak sauce stock main bearings and ring pack configuration. Looks like a decent build. I'm not a builder so don't bash on me, just found as good reading and thought I'd share.

 

My engine has +51K miles of moderate daily driving. As far a wHP my goal is to get around 500, I hope that would be enough to have fun on my daily use. I will definitely give this guys a call or drive over there so I can have a better picture of the whole deal. I still don't like the idea of having the block out for a couple of weeks for machining unless it is absolutely necesary. Thanks

 

Then do what I did....buy a used block....have them build that.....then it will just be a few days for them to swap it...plus you have a stock motor on the side

 

That sound like an excelent idea. I'll do that. Thanks for all the info!!!

 

words of wisdom

 

you could just buy my motor. just a thought

https://my350z.com/forum/engine/4469...longblock.html

 

If you want I have a stock block you can buy and build. Cheap. I'm in FL also. Pm me.

 

The answer almost always as far as boring is absolutely. Even from the factory, the bores are not perfectly symetrical

Your next step needs to be away from the keyboard in all honesty, and start talking to machinists in your area who are well regarded. Not shops that sell built motors, actual machinists. You're time will be well spent, and the money won't be potentially tossed away.

A couple weeks for machining/block assembly is asking way too much IMHO - machinists worth using are like any other skilled laborer - things take longer than expected because they are in demand. As XKR suggested the best thing you can do is to buy a spare block, and build it out of the car. Allows you do conduct your build and let the machinist take his time without you calling and hocking him every 2 days, while you still are enjoying your car

As far as bearings, again, ask the machinist - the bearing/oil relationship is important, and he/she will guide you in the right direction as to all the components he/she is comfortable with you using. While not an FI build, my engine has been going strong now for 2 years, 8400 rpm redline, stock Nissan bearings., no oil cooler. The engine uses not a drop of oil between changes, and I stick to using the oil and filter my machinist told me to (if it ain't broke, don't fix it...it's his time/skill on the line at the end of the day). Mine doesn't generate the type of heat that an all out FI build generates, but mine does deal with sustained high rpms. But again, this is all stuff that the machinist will go over with you, and either can provide the parts, or give you the marching orders on the stuff he wants you to bring him when it's time to start putting it together.