I did my first motor rebuild two years ago and I've always wanted to go back to recheck the clearances to see how tight it was put together and why it had a tendency to burn oil under high load and rpm. I didn't have a lot of the tools that I do now, so I couldn't check a lot of the stuff that I now consider fundamental to building a motor.


I got the chance to do it when I chewed up the #1 rod bearing at an auto-x. I think I understand what caused that failure, so I'll go over the reasons for why I think it happened.


A couple of other things I'll also show'n'tell are: the wear characteristics of the OEM moly Type-R piston skirt coating, main & rod bearing wear, odd cam lobe wear, and a couple of tools I now use to mic the clearances.

-------------------------------------------------------------------
The first time around, I used the Spoon P73-00 [std bore] pistons. This time around, I'll be using P73-00 [.25mm OS] pistons. I haven't checked the masses on the old Spoon P73-00 pistons yet to see how closely they balance them, but for the new set:
320g, 320g, 320g, 319g

From my old P72-A0 [std bore] pistons: 302g, 302g, 302g, 303g

All of the wrist pins I've ever sampled are 88g. All of the .25OS ring packs I've ever measured are 18g. I've sampled 16 wrist pins and 8 sets of ring packs.

I haven't gotten a new gram scale that reads out to .1g yet (Proform-66473), so I'm still relying on my old one to read out to the closest 1 gram (Proform-66466).

Pictures of the moly coating found on the piston skirts of Type-R pistons after 25k miles:




Piston-to-Cylinder Wall Clearances were:
cyl 1.) .0025"
cyl 2.) .0022"
cyl 3.) .0025"
cyl 4.) .0028"
Spec clearances are: .0004" to .0016" (service limit = .0020")
-I was more than twice my target clearance, and almost twice the max clearance for new.

I originally thought the cause of the oil burning and loose ring end gaps was b/c they honed the bores too much with the ball hone, enlarging the bores too much and causing a severe bore taper condition. It's almost impossible to do that much damage with a ball hone, so that wasn't a very credible explanation.

Bore taper and out-of-roundness were both no more than .0010". Spec limit is .002". Nothing wrong here.

I traced the cause to the smaller skirt diameter of the JDM ITR pistons. The JDM ITR pistons were roughly .0005" to .0010" smaller than my original GS-R pistons. I always figured that they would be larger b/c of the extra thickness of the coating.

There must also be something about the new rings that were used for the end gaps to be so loose.

Ring end gaps were (in general):
cyl 1.) Top - .026", 2nd - .024"
cyl 2.) Top - .026", 2nd - .023"
cyl 3.) Top - .023", 2nd - .024"
cyl 4.) Top - .025", 2nd - .024"

Top Ring Spec = .008" - .014" (service limit = .024")
2nd Ring Spec = .016" - .022" (service limit = .028")


I measured one of my oil scraper rings and that was around .050". Specified clearances are: .008" - .020" (.028" limit). Wow!

-------------------------------------------------------------------

Most of the material ended up in the oil pan and pick-up.








Damage to the #1 rod journal: It wasn't real bad, just a little scoring. A micropolish should be able to take it out. I'm debating whether to reuse this crank or the spare ITR crank I have.


Heat stressing on the rod big-end. I'll be using ITR rods and throwing this one away.


Comparison basis for heat discoloration. This is the #4 rod.


Possible cause of oil starvation, maybe?


Flange of oil pick-up that shows oil blow-by. If anybody has a picture that shows that this is definitely not the norm, please post it. I'd appreciate knowing that this is something I really do need to worry about.


#1 Rod big-end heat discoloration. You can also kind of see the moly coating wear as well in the background.




The other possible culprit is running too much ignition timing on the HI cam map. I had recently switched from using a JDM P30-scaled startmap to a JDM P72-scaled startmap, and the P72 map runs a lot more ignition timing on the HI cam map (as much as from 3 to 10 more degrees of advance in some parts). I shouldn't have hurried to do the race and spent some time on the Mustang Dyno. I'll post the screenshots of the Hondata maps when I can get them off of the laptop.

-------------------------------------------------------------------

Main bearing clearances were all .0014". Not what I would have set them to if I had known what I know now.


Main bearings (all):


Main bearings 5 and 4:


Main bearings 3 and 2:


Main bearing 1:


Rod bearing clearances were (as measured with Plastigage):
cyl 1.) ----not measured [ACL - I left one in as an experiment]
cyl 2.) .0013" to .0014" [Honda brn]
cyl 3.) .0013" to .0014" [Honda blk]
cyl 4.) .0019" to .0020" [Honda grn] - I had set the clearances to ~.0015", I believe, over the winter when I swapped the #2 to #4 rod bearings from ACL to Honda rod bearings.

-------------------------------------------------------------------

Here are some shots of the Mitutoyo bore gauge, Digimatic indicator, and 3"-4" mic that I use:







I used to use a regular dial indicator, but I've found the digital ones a lot easier to use. Now I just need a 2" long travel digital indicator for degreeing the cams...that should only set me back around $500.



I use this tool from Snap-on to check the crank thrust clearance:


The car was for sale, but it'll be off the market until I get it back together. I'm seriously considering selling all of my engine building tools as well, but we'll see how it all goes after I get a bike and a beater Civic.

 

Nice post, and nice looking tools.

 

aye, that brings back memories of my rebuild. Haha, my first set of bearings for both the mains and con-rods were too wide and thick, so the clearances in the middle of the bearings were perfect, but they were binding at the edges. Anyways, the engine didn't turn at all when all was said and done Loosened it all up and it spun a little bit, then I stopped, took all the caps off, and everything looked like your #1 bearing A little micropolishing and honda bearings later, everything was fine. Good luck with everything man What kind of bike are you planning on getting?

 

Wow, thats a lot of wear and tear after 25k. I just tore mine apart and looks way different from yours. The heat stressing my guess would be caused from low or no oil going around the bearing area.

Its good to see you use quality measuring equipment. Most people think that using some cheep crap will be just fine, when in fact there is huge difference between quality equipment such as Mitutoyo, starrett, brown & sharpe, and that of "quality import" equipment.

 

I did the best I could the first time around, not knowing much. The clearances have loosened up quite a bit from what I remembered measuring the first time around (of what I could measure). The ring end gaps, for one, loosened up around .006" to .007".

Hopefully this build will go a lot smoother and make better power than the previous motor did.

I want a '01 Gixxer 6. It's the earliest fuel-injected Gixxer 6 and they haven't changed all that much since then. I can justify getting a bike now since I'm in the 25 and over insurance category and with the climbing gas prices.

 

do you know why the clearances, mainly ring end gap, loosened up?

 

I really don't know. The only thing that could wear down and cause the end gaps to loosen up is the cylinder bore diameter. I don't see that as the cause b/c the cylinder bore diameters were all within new spec.

 

oh man, I just saw your video in another thread, and you had some crazy oil burning issues Anyways, about the oil pickup, was that a new gasket? Also, would it be possible for you to check the straightness of the surfaces? When I had mine apart, I didn't have those two oil spewing marks that you do.

 

The oil was never really apparent driving easy, but as soon as I would get on it, it would shoot a puff of smoke. I knew it wasn't a dead ring b/c it would have smoked a lot more than that.

The gasket was replaced on the first rebuild b/c I remember the first one tearing. I can get a straight-edge on the flange of the new & old oil pump & pick-up, and check it with feelers to see if it's straight.

 

hey B, goodluck on the project. those are some nice tools you got there... wanna buy an LS motor for your beater?

 

Very informative post... Goodluck with getting it running better...

 

Hey Big Rand. Maybe I should buy that LS motor and sell the car as is, then sell the motor separately.

Altho, a B18B Civic sounds like a good idea too.
-Skinny Ben on Fat John's SN.

 

im'd u (invtec)

 

Bore straightness problems still seem to be plaguing me:

Here's one of the four pistons I have measured against all four bores. I did that to help me decide which bore I want to stick each piston in to get the closest to the clearances I want. I'm striving for closer to .0018" and no more than .0020" for each piston.

Piston (arbitrarily designated as "1") vs.
Cyl 1.) [top of bore] .0021" , .0022" , .0025", .0022" [bottom of bore], max delta = .0004"
Cyl 2.) [top of bore] .0018" , .0019" , .0023" , .0020" [bottom of bore], max delta = .0005"
Cyl 3.) [top of bore] .0017" , .0018" , .0027" , .0023" [bottom of bore], max delta = .0010"
Cyl 4.) [top of bore] .0021" , .0023" , .0026" , .0022" [bottom of bore], max delta = .0005"

The story is that the first machine shop (D&B Machine) that I sent the block, head, and stuff to the first time were too dumb to measure correctly. All of the pistons were too tight in the bores, and when I say too tight, I mean that they wouldn't even get all the way into the bores. That's just the block work too. The valve job was hand done so that some of the seats were crooked (checked by lapping with 1000grit) and you could see intruding light from the port with the valve installed, the valve guides were hammered in instead of pushed in....I could go on for days about all the stuff they did wrong.

I had to send it to another shop and while the work was better, I'm not sure if I should be completely satisfied or not. Maybe I'm just asking too much and what I have now is good enough. I need to figure out how much an excellent block machinist can get the tolerances before making any further criticisms.

I hope people in my area read this and just say, "**** ever building engines". This **** is getting old.

 

I just did my first rebuild (similar to yours) and I also had problems with machine
shops. When I took my head to get it worked on, the guys removed the valve seals by chopping them in half with a screwdriver. It looked like that damaged
one of the valve guides because I could barely get the valve to slide smoothly
in there. I guess they thought they were working on a small-block Chevy engine. I didn't even take my block to them to get it worked on. The factory hone marks were still visible, so I just slid the pistons in there with the best ring compressors I could find and torqued everything up. Knowing what I know now, it might've been a lot less hassle to just drop a h22a motor in there and call it a day. I'm pretty nervous now because it looks like most rookie engine rebuilds don't do so well.

 

Is the oil pickup gasket hard to get to on a GSR, i am very new to engine overhauls so any info would be great? My car is burning oil pretty bad and this may be the culprit.

 

A lot of good tech info on this thread

 

Excellent post. I dont think I will ever drop my b18c1 off somewhere and have it worked on unless I'm standing over them watching every move! But, nice post I like your style very descriptive!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b18c1acura &raquo;</TD></TR><TR><TD CLASS="quote">Is the oil pickup gasket hard to get to on a GSR, i am very new to engine overhauls so any info would be great? My car is burning oil pretty bad and this may be the culprit.</TD></TR></TABLE>
Not at all as long as you don't get hung up on rusty header or collector bolts. It's just a step further from dropping the oil pan.

I don't see how burning oil and the oil pump pick-up are related. It's not pretty far removed from the combustion chamber.

The frustration makes me want to go to the School of Automotive Machinists and then go into debt for the rest of my family's lives to buy all of the equipment and do everything myself.