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RB26 Rebuild Costs?

jlabsurf

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

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jlabsurf Contributor

jlabsurf

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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.

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jlabsurf Contributor

jlabsurf

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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

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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

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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

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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.

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