Hi everyone,

I'm in the process of having my engine rebuilt and I'm starting this thread so I can ask questions, update the status of my build, and post my results and any issues that come up. I've spent many hours reading several other threads about engine builds and I've found them very useful. Maybe others will find this thread useful as it progresses.

Background:
This is an N/A build for a VQ35DE from a 2003 350Z. I hadn't planned on having a built engine, but a few months ago I got a cylinder #5 misfire code at the track, and after the usual diagnostics (compression test, etc), it turned out that the #5 piston had started to crack near the edge. I go to HPDE's at the track, so I run the car fairly hard for 25 minutes at a time. My goal is not to increase the horsepower from what it was before, but rather to increase reliability. I want the engine to be strong enough to withstand this kind of track "abuse". However, if there's some extra power to be had, I'll take it. I have several pre-existing engine mods: JWT pop charger, Crawford plenum, Berk high-flow cats, Fujitsubo titanium exhaust, Uprev reflash & tune, an oil cooler, and a Koyo 54mm radiator.

The components:
Since my goal is not to increase power, I decided to keep the stock camshafts and exhaust manifolds. Here are the parts I chose for the build:

Wiseco 96mm 11:1 compression pistons (0.020 over stock)
Eagle rods
Nissan OEM main & thrust bearings
Cosworth rod bearings
Nissan OEM head gasket
New OEM water pump, new RevUp oil pump
New engine gasket & seal kit
ARP main studs and head studs
Nissan OEM camshafts (using my existing ones)
Nissan OEM valve springs (new)

JWT lightweight flywheel & clutch kit (replacing my OEM flywheel & clutch)
Fuel injectors tested & cleaned by RC engineering


Short block work:
The short block machining & assembly is being done by Bill at Performance Crankshaft here in Austin. So far he has bored & honed the cylinders to 0.020 over stock to match the Wiseco pistons. He DID use a torque plate, which I rented from Forged Performance. He has also balanced and polished the crankshaft. This week he is doing the final assembly of the components, and he'll check the clearances, etc.


Head work:
I'm having the heads "cleaned up" by a guy here in Austin named Brooks Elliot (www.austincylinderhead.com) who comes highly recommended. If I remember the details correctly, he is doing a 4-angle intake valve job, and a radius exhaust valve job. He noticed that the cylinder head for cylinder #5 (the one whose piston came apart) had some slight scarring, so he smoothed this surface out and made sure it held the same volume as the other cylinders.



This is the first time I've ever had an engine built. To be honest, I'm pretty nervous about it -- I read all this stuff about how the clearances all have to be exactly right, parts all assembled exactly right, and I read these threads about engine builds gone bad and it scares me . I just want the engine to run as close to perfect as possible, and I want to know that I can go run it around a track for 30 minutes at a time and not have to worry about it. Keep in mind this is an N/A build, not turbo! I'll post updates as they happen.

The block & heads should be done this week, and next week we'll be putting it all back together. At the suggestion of Rich at Uprev, I've purchased Torco TBO oil for the initial engine startup and first 30 minutes of engine run time. (TBO is designed specifically for this purpose). Then I plan to drain the oil and put in the usual oil I've been using, which is Torco SR-1 10W30 (synthetic). Then I'll do the break-in to seat the rings, and run it for a few hundred miles and replace the oil again. If everything seems fine after 500-1000 miles, I'll take it to the track and have fun.

In the meantime, I welcome any advice, questions, feedback, from you guys, especially the ones who have been there, done that (Adam @ Z1, Sharif @ Forged, Kyle & IPP, to name a few, as well as the DIYers). A small suggestion from one of you now could save me lots of time & money later. I just want to do it right the first time, even if it costs a little bit more. Thanks for reading.

 

I know already that you do not wish to increase power, however doing the camshafts and headers would be much easier and much cheaper now than later down the road.

 

looks like you got your bases covered to me

only 2 things that caused me a headache was bleeding the coolant system of air (you may want to block out an afternoon lolololol), and then the rear main seal. Take your time with the seal and make sure its seated properly, and you'll be good

 

Talk about being ****..

Is this engine also going to be running as your daily or just HPDE events?

Some of the parts and services you mentioned might be a little over the top IMO. Instead you might want to look into plumbing in an external oil cooler and oil filter, A larger radiator, using better lubricants, and running race gas at HPDE's.

 

Yeah, while the motor was out i definatly would of replaced cams and manifold, I know your end game isn't extreme power. but it's not like a little more would of been bad.

 

I definitely hear ya... it was a hard decision not to get cams. But the cams I would have gotten are $1300, plus I would have needed some better springs for that, and I'd be tempted to get headers, etc. I should have mentioned that I plan on getting a 370z in 1-2 years, which affected my decisions.

Thanks for the heads up. I've bled/burped the 350z cooling system once or twice before, so I know that can take a while. I'll tell my mechanic to take his time on the rear main seal as well.

This is one place I have no problem being **** -- an engine build! It's going to be a semi-daily driver and a track event car. I already have an oil cooler and a larger radiator. I use Torco SR-1 oil and before that I used Mobil1, and I change it every 3000 miles, or between each track event, whichever is sooner. I may experiment with 96 octane sometime.. I'm not sure the engine would know what to do with 104 or 110 octane unless it was tuned for it. Plus that gas costs an arm and a leg! see pic

 

Why new rods? Why not use revup rod bearings?

 

One of the rods was slightly damaged, so I had to replace at least one anyway. I probably don't need the strength of eagle rods, I admit. I got the Cosworth rod bearings because (1) they were only $100 anyway, and (2) I wanted at least one Cosworth component in my engine, so I can justify my Cosworth "Power to Pass" license plate frame


In other news.. I got the heads back from the head expert, Brooks Elliot, today. They look awesome. He ended up doing a 5-angle valve job on the intake. Here are some pics. The first one is the machine he uses to do the actual valve cutting. He programs in the angles he wants, and tells the computer approximately how much metal is already there, and the machine cuts each valve seat in about a minute and a half. The screen in the 2nd pic shows the 5 angles (if you look closely). The line on the left is where the metal was originally, and the lines on the right is what the machine will cut (the 5 angles). The difference looks big, but it's actually millimeters or less. The last pic is just one of the heads wrapped and ready to go.

 

This is a good start to this thread! I had a misfire/cel on #5 cylinder as well took the plug out and it looked like it got decapitated, where and how do you do a leak down test, and whats the cost?

 

Just a quick update... I got the short block back from the machinist/builder today, and my mechanic has started putting it all back together. I'll try to get a pic of the block, but it looks the same as any other freshly-built block I should have it back within 2 weeks (my own estimate), but I'm not in a rush -- I told my mechanic to take his time and do it right


Most good auto repair shops can do a compression & leakdown test. The cost is probably by the hour, and I'd allow 1-3 hours for a full leakdown test. Just a compression test should take an hour or less (although I don't speak from personal experience).

 

Good luck with the build Chris. Who is putting the motor together for you? I think you're nuts to not try to get a few extra ponies out of her, but I guess you're already fast around the track to begin with.

Were you able to figure out why your piston cracked?

 

Bill @ Performance crankshaft assembled the block, and my regular mechanic (his name is Travis) is putting everything else back together.

I don't really know what caused the piston to crack. It could have been something that was caused by overheating once and then got worse over time, who knows. It looks like that right bank was running hot though, so maybe it was lean. This time I have wideband on _both_ banks! BTW I'll be at the Z club meet at H2R next weekend instructing, but I don't think my Z will be ready by then unfortunately.

 

Do you plan on running any time trials with NASA this year? Based on your TWS times (not sure what you run elsewhere) you should kick some a$$. I really enjoyed it last year until I got my comp license and started door to door racing.

 

Nice~ :-)

But while you have the motor out, you could do some performance mods pretty inexpensively and still keep it reliable.

 

Ok finally an update! We finally got the engine together today. We tried to start the engine, and it would crank but we weren't getting spark (we were getting fuel just fine). We checked the crankshaft position sensor, and I replaced it just to rule it out ("throwing parts at the problem!"). To make a long story short, the culprit turned out to be a grounding problem. On the very very front of the engine, where the wiring harness kind of wraps around it, there is a small ground wire that sticks out of the harness. That hadn't been grounded to the engine. When we grounded it, it started right up! Man it was a relief to hear it running.

Everything went okay so far. Good oil pressure, no apparent oil or coolant leaks. No strange noises. Not even very much smoke (which is common for first-time startups). I monitored the coolant temp closely with a scan tool. It got up to about 203 degrees F, so we shut it down. It's almost for sure air pockets in the coolant. The engine was completely dry so it may take several burping sessions to get the air pockets out. It logged about 15 minutes of total run time so far (idling, a few throttle blips). Tomorrow we'll get the air pockets out and finish the details like the interior, underpanels, etc.

 

What the F??? When did this happen? I want a ride when you get the motor in, PM me

 

good stuff man! Any questions on anything let me know, I'll be online most of today working on mine

 

Ok we got everything together, changed the oil & filter, and I drove it around. I'm keeping it under 4000 rpms and not going full throttle yet. One thing I'm not sure about, maybe someone can answer: I replaced the OEM flywheel with a JWT clutch and flywheel. I can hear the usual flywheel chatter at idle, but when I accelerate from a stop in first gear (or in second gear from a stop), there's a noise and I'm not sure if it's the flywheel or something else. It definitely sounds like drivetrain as opposed to the engine... the noise is hard to describe, especially since I've only heard it from the driver's seat with windows open. I can't hear it with the windows closed. Adam (or anyone else) if you can think of common things to double-check that might cause this kind of noise, that'll give me a lead

 

totally normal for a lighweight flywheel - my car does it as well. Sort of a very fast rattling sound that magically goes away at around 2200 rpm or so, in any gear

 

Adam thank you! -- that is exactly the noise I'm getting, your description fits it perfectly. That's a relief... now I can get on with breaking it in.