How do these rod bearings look? They all have 300 miles on them, same with the crank journals. I know 4 and 5 are looking pretty haggard but how are the rest of them? They're Mahle/Clevite 0.25mm oversized (details below)

I recently dumped about $4500 into a professional rebuild for my Revup. About $2200 in parts that I supplied and $2300 for the full assembly which included valve work and a number of other things that I was probably up-sold. Whatever. I hired them mainly to check all my clearances and to assemble the rotating assembly, but I ended up having them assemble the entire engine. They never told me the bearings or anything was out of spec. I'm still working with them on solving this so not sure what deal will be worked out but I see myself doing the ol' shoestring and sandpaper from here tbh fam.

Long story short on the rebuild: I spun the cyl 1 bearing a while ago from overheating which ****ed the crank journal noicely. I had a shop weld and grind all rod and main crank journals down to 0.010" (0.25mm) to prepare for a rebuild. The new shop did the actual assembly and took the time to check over everything with me before assembly, so I trusted them.

For the the life of these bearings, I ran Fram non-synthetic 5W-30 oil with a Nissan filter. I was told specifically to use shitty dino oil to help with break-in. When I drained the oil, there was a **** load of super fine metal shavings all up in the pan. My magnetic plug didn't have a chance. I guess I should've done an oil change or 5? I've yet to crack open the filter but at this point who gives af. I followed the shop's break-in guidelines to a T, they said 500 miles is no issue for the first oil change. I've since ordered a fresh set of DNJ 0.25mm oversized rod bearings and new bolts to yeet in as a last ditch effort to salvaging this build. Too bad too cause the new Sparcos and solid bushings are sick.

Thanks

 

Uploading a copy of the build sheet might help someone chime in.

 

Your bearings look like they overheated and appear burnt. I suspect your journal to bearing clearances were incorrect.

Did the shop that assembled it check the crank journal to bearing clearances ?
One way to do this is with plastiguage:
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+1 on the plastigage. It looks like cyl 4 and 5 have had material fatigue and has warped the inside diameter. #4 is obvs the worst so you should start there. Actually you should start by yelling at the machinist/builder. Luckily your journals look ok so you caught it in time.

 

All I have is the invoice, hope this helps!

It should be noted these guys more specialize in performance US-based engines like Ford and Chevy. If I ever do another build, I'll go to a specialty shop for my engine type I suppose.



Good to know, thanks! I'm not very familiar with break-in patterns or what would look normal. 4 and 5 are curled a bit and def stand out, I imagine those are what you're talking about. What you think about 1-3 and 6?

I made it super clear that clearancing and assembly of the rotating assembly was just not something I wanted to try and learn on this build so that was central to the scope of work. They even had me buy a separate set of main and rod bolts for testing and a fresh set for assembly since they're TTY. I knew the bearings I supplied were close to tight spec on the mains so I told them I'll def get different bearings if needed. They're cheap anyway. They said they ended up plastiguaging everything and I got no push back from them on it. I also supplied the FSM documents for reference but I think they were able to find all that with their own system pretty easily. The rest of the motor was beautifully assembled, exactly what I wanted.

 

A proper build sheet would show the measurement and tolerances of everything. ^^ Not a build sheet.

1-3 and 6 opinion: My OPINION is that they possibly show premature wear. My experience is that at that mileage, they should look brand new. A before and after picture comparison might confirm this.
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What was the shop owner's response and explanation when he/she showed you these bearings? How much experience did the person who installed the bearings have? I hate to say it, but some machinists and shops do not appreciate import engines and working on them.
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I've seen shops screw up just about everything. Bores out of round or too big or small, ring gaps too tight, cam bearings not installed all the way, incorrect main and connecting rod bearings. . . . . IMO engine building requires an expertise similar to that of a brain surgeon. Unfortunately we often get a lousy machinist that thinks he knows what he is doing. Even large engine re-manufacturing companies have this problem. Google Jasper engine problems.
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Cool, I'll reach out for a build sheet from them. Sounds like a great accountability tool. I'm not expecting to get one though tbh, I just have a feeling.

I haven't shown the shop the bearings yet. Just got them out last night. The shop owner or manager did come out though to look at the motor while it was knocking. We also drained the oil. We haven't discussed reimbursement yet but I'm planning to demand at least $1000 back since the VAT is nulled out now and it's clearly a botched assembly. I still have a bitchin valve job and heads I suppose.

I agree with the wear startement, they look a bit marred and I wasn't expecting that. When I first pulled Cyl 1, I cringed. Then 2. 4 made me lol. Here's the new DNJ for reference.



DNJ baybay

 

Also, in case anyone has ideas on this bad boy... Not saying it's excellent timing on my wallet or anything

 

Is this a machine shop that you took it to? "Long block assembly" doesn't sound like they did any machine work on it.
Hope you paid with an American Express. I would look into filing a charge back honestly.

 

Naw, good ol' Debit. Machine work wasn't necessarily the goal with this shop but of course I'd have them do it if necessary. The crank came to them already welded and ground down .010". The block had already been decked and honed and these guys charged me for light crank journal work to make sure Cyl 1 was smooth as possible since that was the original, more severe problem.

I'll work with them and start at a full refund. I feel like that's legitimately fair but we'll see how that goes and I'll act accordingly. Putting the VQ back in the car, while wildly successful, was wack. And after just rebuilding the rear end while spending another few thousands on chassis performance parts hasn't made this situation any sweeter either.

 

Theres a few good break-in procedure videos on youtube I can link if you like…

After-thought edit:
You should have changed your oil after 5min of run time and/or maybe 5miles of easy driving, just enough to get the oil hot, flowing, and capture as much wear particles as you can … this would have cleared out most the metal particles that came off during a fresh rebuild. Easy driving/light load is the opposite of what you want to break the engine in. After that you’d want to use a formal break-in oil for the first 500 to 2000miles of increased load. Some break-in oil you can drive aggressively on.

You spun the bearing on cylinder #1 and you sourced repairs and replacement parts and handed everything off to the shop without checking everything over. The shop ‘should’ have given you a report of your big-end rod diameters, your crank journal diameters, your bearings, and your oil clearances (based off your direction). That would be the best card to play at this point in time. But I think you hold the lion’s share of blame bc you supplied the parts.

In-reality - the measure of the rods/crank/bearings/oil clearance is 6th grade math and you should get involved with your build to the fullest extent.

I suspect that you ran the car with oil that had metal particles in it and it started to clog the oil passages and I doubt it fully clogged anywhere specific but rod journals 3 and 4 are the two furthest from the oil pump and they were likely underoiled. Coolant does a great job cooling the block, but what cools the engine internals? Oil does…

Are you running a traditional oil filter setup? Running an oil cooler?

What are you doing with your built VQ are you gonna JZ swap soon? Looks like a fun project and there are a few really good JZ swap builds here.

If it makes you feel better I spun a bearing pretty good(cylinder 4) back in late-2018, then earlier in the year I blew-out a valve seat, and on my rebuild, I got about 100 to 150miles on my block and sure-enough spun a bearing(cylinder #3) - I believe I made my oiling system too complicated, too much oil cooler/filter hose and I was under oiling at high RPMs. You live, you learn…

 

I hear you on changing the oil within 5 or 10 mins. It seems obvious now but I asked at least 3 or 4 times about their recommended procedure. They do build engines for a living, just not Nissan engines apparently. Yeah its a totally factory oiling system, filter included. You have a brand or weight of break-in oil you'd recommend for our engines?

Same with the assembly metrics. I don't have the tools to accurately measure this stuff. I was very clear with them that I needed them to clearance everything according to Nissan spec in the Engine Mech Service Manual, which I provided in case. We were pretty tight on communication during this build so it wasn't hard to just trust them like I should be able to. Supplying my own parts is def a grey area for builders so I get that. At least I bought OE/OEM/Aisin for pretty much everything important.

Dude, I might JZ swap at this point. I was going to save it for an E36 or RX-8 chassis but now I'm thinking I'll just toss the VQ. It needs a full look through though to make sure it wont blow up

 

You live you learn …

my friends dont understand why I love my car so much and why I am not end-of-the-world upset when something goes wrong … I love everything about my z and ever when things go wrong its an opportunity … I’m rebuilding now and I have a serious gouge in my block and my 96mm pistons wont fit in any of the 95.5mm spare blocks I have … I’ve never honed a block before and it seems very intimidating but I got two cylinders done this weekend and I’m really excited to do the remaining four … and from there I am ready to rebuild.

If you followed their recommended procedures than there is some blame to transfer over … at the end of the day pointing fingers and assigning blame doesnt get your car back on the road.

I like Driven brand oil … It’s not horribly expensive but it’s not cheap either … they have a really good customer service team and if you tell them your engine specifics they will tell you the best break in oil to use. I used BR 10w-40 … but email them and ask them which one you should buy.

https://drivenracingoil.com

They also have some good videos / content on engine oil on their site you could check out too.

Here are a few good break in procedure videos …



I didnt watch this one in-full but Lake Speed Jr. and Total Seal are both industry leaders in performance engines


If you want to dip your toe into engine building and want to invest in the tools to do so it’s really not that expensive - I’m gonna say $500 to $1000 will buy all the measureing devices you would need. I’ve been getting in to it over the past few years and have bought a few hunderd dollars of equipment each time. Same thing goes for tools to rebuild an engine … the bigger thing is a place to work, spread-out, make a mess, clean things, store stuff, etc.

It’s a little life lesson … check and re-check …

You should review the JZ builds that people have done here … it’s not ‘nothing’ but it’s very do-able and those engines can take much more power than the VQ.

 

Tolerances look way too tight, that should have been caught by them 100%. They are responsible here IMO.
If you’re trying to save it, use plastic have and get a proper measurement, you’re gonna need thinner bearings by the looks of things.
Thats brutal btw, do 3-4 oil changes after you’re done with the bearings. Add a small amount of trans fluid as well or sea foam to help flush the galleries.

 

Did I miss where the oil bearing clearances were stated? Or are you basing this off the condition of the bearings?

 

I didn’t see clearances posted, I’m basing my opinion on the condition of the bearings. No signs of egg-shaped wear on the bearings, so by looking at the photos it doesn’t look like an oiling or failed bearing problem but more of a tight tolerance problem.
Hard to say for sure as we’re just looking at photos, but the one bearing is completely worn, not just in some areas, which leads me to believe the tolerances were not checked, and the engine was not turned over by hand without heads after assembly.
Im not an engine builder, but these are my immediate thoughts.

 

What do the other halves look like?

 

^Good question…and I was wondering if the caps are installed on the correct rods, and in the correct position.

 

Some things I have noticed from my engine rebuilds . . .

1. When I targeted rod and main journal sizes at the bigger end of the tolerance specifications, that my engines would rev higher, run cooler, and last longer. i.e. if the journal tolerance was + .001 to .003, I would target .003.
2. Ring gaps, same as journal gaps . . . target the bigger gap tolerance if possible.
3. Line boring, decking the block and balancing my engines (and tuning the exhaust) always resulted in a better running engine.

In my opinion, these are things that definitely make a difference, but are seldom done unless asked for.
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Dude thanks for all of the info around this, definitely helpful! And yeah, I think if getting money back is more worth my time than removing and reinstalling the motor, I might just JZ it up and send it. Everything else I've installed can be transferred to a Z one day which is pretty sweet too. I should update my mod list

So I only accurately (Plastigauge) measured the mains and they were right on the line of tight within clearance. I tried to measure the rods but wasn't confident in it and I decided to pay for my time back and have the shop measure and assemble. They never provided numbers but they did burn through one set of assembly bolts and told me they measured everything. They already said they don't really keep records for those things. I can believe that, its an independent builders shop so their way is probably been that way for years.

Great question, I've yet to pop them out. 4 and 5 were loose though so that was mimicked on the cap side.

Good to know, this I'll remember! I just watched a video of a dude explaining his crank balancing procedure, pretty intense.

I think the writing on the wall so far is the crank likely needs more work, plus whatever else could benefit at the time. And bearings sourced from a shop that knows how to get what they need, for Nissans. And whatever else would be needed from a complete disassembly/reassembly. Does the motor need a full disassembly or can you fudge the pistons in from below? Guess I can't yeet new bearings in and adopt a new break-in routine lmao. I'm gonna call the machine shop today and we'll see what's up.

You guys are all super helpful so thanks for chiming in with your thoughts! I think from here it's either a free rebuild if possible, or a JZ swap