Jump to content
SAU Community

RB26 Rebuild Costs?

jlabsurf

By jlabsurf,
in R Series (R30, R31, R32, R33, R34)

 Share

Recommended Posts

jlabsurf Contributor

jlabsurf

Posted
Posted

So basically I dropped my engine off at the tuner running perfectly fine.

Tuner was supposed to adjust timing and tune my haltech. He said he forgot to re-tighten my adjustable cam gear on the intake side and because of that I have bent valves in cylinder #3.

My compression on all other 5 cylinders is really good, cylinder 3 is 0. I can't even get a compression reading.

 

I sent my head off to NAPREC here in Japan and they are doing the high response kit to fix my head. naprec.co.jp/product_en/hrk-rb26

Besides the high response head service (1600$) what do I need to do and what is the cheapest route I can go to get my engine running again?

Just replace the one piston head in cylinder #3 and make sure it is balanced and slap the head back on good to go?

 

The tuner that damaged my head said its more cost efficient to just buy a new motor 6000-8000$ than to take my current motor apart and fix the damages that have been done. That  just doesn't seem right to me and that is why I am asking.

Link to comment
https://www.sau.com.au/forums/topic/479366-rb26-rebuild-costs/
Share on other sites
jlabsurf Contributor

jlabsurf

Posted
  • Author
Posted
Just now, Murray_Calavera said:

This might be a silly question but isn't this a problem for your tuner? 

Surely the onus is on him to sort out the engine that he damaged?

Unfortunately he wanted to argue and put the blame on myself and then charge me for the "timing system" twice. Stating it was I, who left the cam gear loose.

I know for a fact I did not, but unfortunately there is no way I can prove that legally. Heard a lot of bad things about the guy but decided to give it a shot because he's the only one that tunes haltechs in this region of Japan. Definitely learned my lesson.

Ben C34 Grand Master

Ben C34

Posted
Posted
39 minutes ago, jlabsurf said:

Just replace the one piston head

What do you mean? Replace the piston?

In what way is it damaged.? I'm assuming it hit the valve, but does it have chunks stuck in it or cracks.?

jlabsurf Contributor

jlabsurf

Posted
  • Author
Posted
Just now, Ben C34 said:

What do you mean? Replace the piston?

In what way is it damaged.? I'm assuming it hit the valve, but does it have chunks stuck in it or cracks.?

I haven't had the time to put a camera in or pull it apart because of work. But I'm assuming because the valve hit the piston head hard it will have a sizable dent in it at the very least. Which I was told will create hot spots and cause pre-ignition.

Murray_Calavera Mentor

Murray_Calavera

Posted
Posted
13 minutes ago, jlabsurf said:

I haven't had the time to put a camera in or pull it apart because of work. But I'm assuming because the valve hit the piston head hard it will have a sizable dent in it at the very least. Which I was told will create hot spots and cause pre-ignition.

I thought you said you sent your head off? 

With your bottom end, how much of the work will you be doing yourself? 

jlabsurf Contributor

jlabsurf

Posted
  • Author
Posted
Just now, Murray_Calavera said:

I thought you said you sent your head off? 

With your bottom end, how much of the work will you be doing yourself? 

Sorry let me clarify, I never got the chance to take off the head myself with work and all so I haven't had a chance to take a look at the damages. Had a friend take it off for me and ship it to NAPREC as the car is currently at sitting at his house. This was last night.

At this point I'd like to do it all myself as I don't feel I can trust the local shop and most performance shops out here are an hour or two away minimum. It will be my first time disassembling/reassembling the bottom end if I have to. Everything else I have experience with.

Ben C34 Grand Master

Ben C34

Posted
Posted
25 minutes ago, jlabsurf said:

I haven't had the time to put a camera in or pull it apart because of work. But I'm assuming because the valve hit the piston head hard it will have a sizable dent in it at the very least. Which I was told will create hot spots and cause pre-ignition.

I would be way happier with a ding in a piston than having just one replaced. Deburr it of course. It won't cause a hot spot, pistons already have notches for the valves, so a bit bigger isn't a deal breaker

Duncan Grand Master

Duncan

Posted
Posted

Putting aside the tuner's responsibility...

You need to look at the top of #3 piston to decide how much damage it is. Every engine with a few klm on it will be pretty dirty so clean it up with a scotch brite pad and see what the damage looks like.

Assuming it looks OK, next question is, how many klm on the engine, when you say the compression is "really good", what do you mean, and does it smoke or use oil. If all of those point to the bottom end being in good condition, leave it as is and just replace the timing belt etc, head back on and cross your fingers.

If there is any sign the bottom end is tired, now is definitely the time to deal with it, pull it out, disassemble, measure and put at least new rings and bearings in

jlabsurf Contributor

jlabsurf

Posted
  • Author
Posted (edited)
27 minutes ago, Duncan said:

Putting aside the tuner's responsibility...

You need to look at the top of #3 piston to decide how much damage it is. Every engine with a few klm on it will be pretty dirty so clean it up with a scotch brite pad and see what the damage looks like.

Assuming it looks OK, next question is, how many klm on the engine, when you say the compression is "really good", what do you mean, and does it smoke or use oil. If all of those point to the bottom end being in good condition, leave it as is and just replace the timing belt etc, head back on and cross your fingers.

If there is any sign the bottom end is tired, now is definitely the time to deal with it, pull it out, disassemble, measure and put at least new rings and bearings in

My car just broke 200,000kms. I have no idea how many km on the engine.. That being said the engine was maintained by Omori Nismo Factory in Yokohama until about 2017 by a single Japanese owner. Never asked him if the engine was replaced or rebuilt or anything like that. Then owned by myself since 2017. The bottom end made no noise what so ever and when I compression tested prior to taking it to the tuner I was getting 166-168psi on all 6. After the mishap with the tuner I was getting around 152-154 on 1-2 & 4-6 besides #3 while the engine was cold. I didn't want to let the engine run long enough to get it warm. The engine would not use any oil and no smoke what so ever. When I took it apart before there was still a perfect cross hatch and no damage on the piston heads(stock) at all. I cleaned the top of the pistons already when I changed my HG so there shouldn't be much to clean.

If I were to rebuild the bottom end at home for my first time, what kind of job am I looking at and how much if I do it the right way? I've many years of experience working on cars and a decent amount on rb26s just never rebuilt a bottom end.

 

 

Edited by jlabsurf
KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

The right way is to do what is required. Don't pull it apart just for the sake of it. If you do decide to open it up then observations and measurements will determine whether you just need rings and bearings or a full recondition.Get a copy of the workshop manual and that will tell you what the tolerances are.

Duncan Grand Master

Duncan

Posted
Posted
11 hours ago, jlabsurf said:

hen I took it apart before there was still a perfect cross hatch and no damage on the piston heads(stock) at all. I cleaned the top of the pistons already when I changed my HG so there shouldn't be much to clean.

Sorry I might have missed this, but you had this apart the valves were bent?  Either way, if you can see cross hatches in the bore then it was probably rebuilt reasonably recently.

Assembling a bottom end is not rocket science, particularly with the manual available (although i've learned through experience to always double check the measurements).  All the machining (and preferably cleaning) needs to go to a machine shop. You'll need new rings, big end and main bearings, spiggot bush, rear main and crank seals and all gaskets. Consider putting in a new oil pump too.

However, since it had good compression, didn't burn oil and bores looked clean, I would not be doing anything with the bottom end.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • MBS206
      Rear subframe stay bracket bolt removal issues

      By MBS206 · Posted

      Great work! Give it a clean up with some Emery paper, and I'd run a thread die over the threads too to clean them up. It will make reinstall much easier, and also life easier for the next time it needs to come out.
    • MBS206
      NC MX5

      By MBS206 · Posted

      I'm not a fan of high humidity, it's one reason I don't mind being further inland out Ipswich, except the last 3 odd years, the drought broke, and it won't stop raining, which is making the humidity nearly unbearable when the rains are in during summer! For me, my body hates the cold, once the cold sets into my body, I'm totally screwed. I end up with severe muscle spasm in my back/shoulder muscles, and it feels like someone is trying to tear the muscles out. I have no issues with it getting stupid hot, so long as the humidity goes away. So the last 3 years as above, have been woeful! Ha ha. However, June 1st, and I'm only just converting from shorts and a tee, to long pants and a t shirt. And that's mainly as it's a bit wet and miserable and I wanted to work on a car.
    • The Bogan
      NC MX5

      By The Bogan · Posted

      I much prefer colder weather to hot weather, and especially prefer cold to hot and humid, Goulburn does gets pretty warm in the hotter months, but, I've found the humidity there is not as painful as even Sydney, the humidity up north is to oppressing for this old rooster  In saying this, it does get rather "nippy" in Goulburn for early morning, late in the evening walks, but nothing that a layer or two, some thermal gloves, and a beanie doesn't fix to make it an enjoyable experience, which is much more bearable to me than the oppression of heat and humidity,  especially at night when your trying to sleep If I recall correctly, a "wise man" once said that the "Southern Tablelands" was gods country, and I will not argue that point with him for the fear of a "permaban" LOL In car part related news: My intake is currently in Botany getting processed for the last leg of its shipping journey to my door   
    • DatsunBanana
      Rear subframe stay bracket bolt removal issues

      By DatsunBanana · Posted

      Had a go at the stuck crush tube this afternoon. Tried things like grips and a chain wrench first but wouldn't just twist straight off. So got to work with a drill. Started small and kept a depth stop on to make sure I didn't drill into the bolt. Made a line of drill holes all the way up and enlarged them. Then a combination of chisel and Dremel to split it all the way up. Levered the split to get oil in there and eventually it gave a bit while levering. Worked it back and forth with loads more oil till it was spinning freely, then with grips I could work it downwards and off. And no significant damage to the bolt (not by me anyway - just the 27 years of rust)
    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      Well, I'm tired. I'm tired because about 4PM yesterday, before today's appointment someone immediately bought my bumper. They couldn't get it any other day as they're on the way back to NSW. So I had to do that big GTR conversion I had been planning. Unfortunately, the information on SAU about what you need and how this is done is incomplete. So what should be a simple bolt on affair, yeah, it's not. Did you know if you use all GTR items the bonnet won't close? This little manuever sent me into about 1am the night before trying to dodge a way to get it closed. I will have to revisit this in the next few days  - or maybe not, I may let a body shop figure it out. It all needs to come up and my motivation to pull the bumper off is low. It also seems to hit things in the bay where the GTT bonnet didn't. Yes I used 100% new OEM GTR items. Today, I had the joy of driving to the dyno looking like this: Given I had roughed in the fuel and given sensible but pretty conservative timing, I didn't really bet on having the car drive out any real difference than when it drove in. Sadly due to a miscommunication and laptop fun and games (and almost bricking the dongle, prayers and firmware updates indeed), I ended up using HP Tuner credits to licence the car that was already licenced. So in the end my laptop was used. It turns out my butt dyno is still well calibrated after all this time. The 325kw was on 74% Ethanol, the 313kw line was on 98. The other line is the 'before' line which was 281kw. While the numbers are pretty low, they're pretty in line with what you'd expect. Even if US dynos bump the whole result up about 50KW, gaining 10-15% is similar gains.  The curve of the cam is pretty much spot on with what was discussed as well. All this said, it still feels bad to not see the number you secretly want to see. Even if the car drove great beforehand, and I knew pretty confidently the car would drive out much the same way it drove in due to the nature of a wellish dialled in LS1 not gaining much if anything at all from being tuned from where it was. As expected, the car isn't particularly sensitive to running it at anywhere between 12.0 and 13.0 - And the initial timing at 20deg and 12.0 made 308KW. So 3 degrees of timing, and leaning it out to 12.7 for 5kw, anything above stopped giving any benefit until E85 (which has an additional 2 deg as before). Car itself behaved entirely fine. I found out that 100C = 1.15V! IAT at about 7pm was 19C. I might mess with the bonnet mounting.. but given the REO NEEDS TO BE CHOPPED TO FIT A GTR BAR this is possibly something I may leave gathering (more) dust until it returns to paint jail.
×
×
  • Create New...