MotorMouth93's 1994 Berlina Black NSX Thread

[MotorMouth93]

So I have good news and bad news.


I'll start with the good: my block is done. I opted to just have the shop that did the machining go ahead and install the rotating assembly because it wasn't much more expensive and this way they can check all of the clearances and what not and I really don't want to fuck it up. They took a bunch of pictures so here you go.


It went in pretty dirty, I didn't really bother to clean it thoroughly since it was just going to get chopped up and cleaned again anyways.

The crankshaft is brown from 25 years of oil varnishing.

Block locked in for resizing.

Wiseco skirt coating removed since it makes it impossible to properly measure the pistons (you're supposed to take their word for it), pistons mic'd for final bore honing, and a new dry film lubricant skirt coating applied along with a ceramic top coat.

Crankshaft locked in for heavy metal install. The new pistons are about 7% heavier than the stock ones, not enough to be concerning but enough to require 50g to be added to the crankshaft for proper balancing.

Slug pressed in and machining a bit more off.

Torque plates bolted up for final hone.

Nice crosshatching.

Block decked and deburred, ready for assembly.

Crankshaft after being polished and sitting in the ultrasonic cleaner for a while.

Factory titanium connecting rod wrist pin holes honed to size, cleaned, and ready for assembly.

Pistons ready to go.

New OEM crankcase breather covers installed, these are discontinued in the USA and had to be ordered from Japan

Bearing shells installed and ready for the crankshaft.

Main caps on.

Pistons in.

Crank girdle/oil distribution rail bolted back up.

And thats it. Shortblock almost done. At this point I just have to bolt on the rear main seal carrier, oil pump, and a few other odds and ends to have the shortblock done with.

Now for the bad news. The guy rebuilding my heads fucked them up. This is a guy that's been around forever and I can't find a single negative thing about him, he's built a bunch of heads for a friend who builds racecars and has never had an issue. I don't get it. During the assembly process he somehow gouged up the deck surfaces and I didn't notice it until I got the heads home and was inspecting them closely. We'll see how this plays out, I'm hoping he's as much of a standup guy as his reputation suggests and that he's willing to fix his mistake. I really hope the damage is shallow enough that the heads can just be milled a few more thousandths and I can compensate with a slightly thicker head gasket, but that only works up to a point since the quench height can start to get too high.

 

[furinax]

Nice pics!

Sorry to hear about the heads. There are always issues with builds and you have to make decisions which balance all the priorities. We all wish we had inspected upon delivery so it doesn't belong a ping pong game. Hope you get it all sorted out.

 

[Mac Attack]

Now for the bad news. The guy rebuilding my heads fucked them up. This is a guy that's been around forever and I can't find a single negative thing about him, he's built a bunch of heads for a friend who builds racecars and has never had an issue. I don't get it. During the assembly process he somehow gouged up the deck surfaces and I didn't notice it until I got the heads home and was inspecting them closely. We'll see how this plays out, I'm hoping he's as much of a standup guy as his reputation suggests and that he's willing to fix his mistake. I really hope the damage is shallow enough that the heads can just be milled a few more thousandths and I can compensate with a slightly thicker head gasket, but that only works up to a point since the quench height can start to get too high.

Sorry. I know it wouldn't be "perfect," but are the gouges in critical areas? If you overlay your new Cometic HG, not 100% of the surface is sealed... Perhaps the gouges aren't too deep or are in locations where it might not matter. Because the concern, as you noted, is in milling the heads:

The service limit for head milling is 0.008" per the SM. If you're keeping the same valves and cams and HG thickness as OEM then Honda has done all the clearance math for you and you should be OK. Otherwise, the quench and relative quench between the intake and exhaust will be off from what Honda intended.

 

[MotorMouth93]

Gouges is a bit of an exageration, but there was some noticeable damage to the surface finish. When I picked up my block I had the machinist who did that look at it and he said it would likely just need to be milled a few more thousandths to clear it up.

To answer your questions about whether it's in a critical area, it's right around the edge of the high pressure oil feed into the head and the embossed ring on the head gasket makes contact with the damage.

Since the block was milled 0.007" my plan is to switch from 0.030 to 0.040 head gaskets to compensate. At TDC the pistons poke out of the block by 0.003" so that would put my quench height at 0.037 which is pretty much perfect.

Also I've decided to pull apart the block and redo the bearing clearances. The guy that built it just used the bearings I gave him which were the same colors as stock which resulted in "fine" but far from ideal clearances. Since I want my bottom end to last I'd rather get everything almost perfect, so I ordered more bearings based on the measurements he gave me and I should have enough to mix and match to get 0.0015±0.0002 for the mains and 0.0020±0.0002 for the rods. I have access to quality measuring tools (Mitutoyo micrometers and dial bore gages accurate to 0.0001") already so it should be a matter of just figuring out what bearing combinations give me ideal results.

My mains are at 0.0017, 0.0016, 0.0017, and 0.0010 with factory sizes and while technically within spec the wide variation isn't ideal, and the rods are at 0.0023, 0.0024, 0.0024, 0.0023, 0.0025, and 0.0024 which are all right at or over the service limit. Overly anal? probably, but after seeing that guys post on the Facebook owners group about developing a rod knock within 150 miles of rebuilding I'd rather spend the rather negligible amount of money on more bearings now than deal with starting all over.

 

[whiteNSXs]

Nice job. I missed my 1994.
Steve

 

[MotorMouth93]

I got the heads back and they look perfect this time. The total material removed was 0.008" so right at the service limit. Does anyone know what the factory quench height of this engine is? I had 0.007" taken off the block and 0.008" shaved off the heads, and the pistons poke out by 0.003". From what I've read, the ideal quench height for steel rods seems to be about 0.035-0.043" and titanium expands less than steel. A 0.040" head gasket would put me at 0.037" and a 0.045" HG would put me right at 0.042". I'm kind of leaning towards 0.040 but I'd like to hear other opinions.

Also the block is torn down again and I have a nice pile of bearings to use to adjust my clearances, but before I can do that I'm going to have ARP rod bolts installed, rods resized, and respin the crank to make sure it's still balanced with the new bolts. I should have done it before, I honestly don't know why I didn't, but better now than after a rod bolt breaks.

 

[Mac Attack]

Because of machinist screw-ups from a guy in SC, I also ran into issues during re-assembly that made me re-evaluate my entire engine build, model it in a dynamics engine simulator (accounting for crank runout/deflection, bearing tolerances, rod big-end dimensional change, rod stretch, piston pin deflection, thermal expansion of the different materials, etc), and then do a lot of custom modifications I've never seen documented for a NSX engine build. So, here's my $0.02 on the squish:

One of the things I wish I had done in hindsight was measuring the OEM piston top relative to the deck. If your pistons are Wiseco and made to their standard C30 specs, and you've only removed 0.007" off the block, then I'd be very surprised if your pistons poke out by 0.003". That must be a heck of a ceramic coating! If you have the assembled bottom-end handy, try the following process I did to measure the true piston-deck measurement. It's kind of an art:

The very slight offset on the piston pin preferentially pushes the inlet valve side higher during the upstroke. I have a relatively tight piston-wall clearance of 0.003" cold and 2618 hypoeutectic pistons. It shouldn't rock much, but more than your pistons if you're using 4032 and the recommended P2W clearance from Wiseco. Anyways, what I did was insert some thick paper stock all the way around between the piston and the sleeve. The paper sat below the deck.

Then, I used my dial indicator to measure the maximum displacement at the piston edge when rocked orthogonal to the wrist pin axis. It was ~0.007".

Then, with the piston at TDC, I used a precision straight-edge across the top of the piston edge, where I had the dial indicator. When the opposite side of the piston was pushed down, I slid feeler gages under the straight-edge along the piston sleeve to check the max clearance. It was ~0.0035". So, when my piston is centered and level in the bore, it is exactly at 0.0" relative to the deck. So, the piston poke of 0.003" that you're reporting from the machinist is probably the worst-case, cold, tilted rock. Or, maybe it's not. I don't know how they measured it, but there's an art and it varies if you're accounting for the piston rock or not. Attached is a pic during one of my various rebuild stages (yes, I had to do this multiple times like you and eventually wound up with different pistons). It'll be worth it in the end. Mine has seen 9k RPM at an estimated 625 crank HP, so I guess I did something right after all.

View attachment 163093

Back to your original question on squish clearance... I don't know what OEM is because I didn't measure the clearance of the stock system as mentioned above. However, I can tell you that with my piston clearance relative to the deck as described above, I used a 0.051" thick Cometic HG. I personally know one other professional NSX engine builder that again had the same piston-deck measurement as me use a 0.045" thick Cometic HG without any problems. I went with the thicker one because the dynamic simulator told me to with the higher engine speed than him. So, there's those two data points for you. That's a stock crank with runout within specs, OEM rods, and let's say nominal bearing clearances of 0.0015” on the mains and 0.0020” on the rods.

Now, to a general discussion on the squish clearance:
There's two squish clearances for the intake and exhaust. Both OEM squishes are conservatively large IMO. I understand why Honda did this due to it being the first production engine with Ti rods and they were conservative for the stretch. Which brings me to a correction from your post - Ti rods stretch more than the steel rods primarily because of the difference in their modulus of elasticity. I'll hit that again later. Look at the combustion patterns when OEM engines are cracked open. There's heavy carbon deposits on the intake and exhaust squish pads. Also, note that the limiting squish clearance is on the intake side where the pad is larger and flush with the bottom of the head. The exhaust squish pad is smaller and recessed about, what, a good 0.05"? When you mill the head, that is the differential squish clearance you are changing - the exhaust squish is being reduced relative to the intake squish, and less mixture will be forced to the hotter exhaust valves, thereby resulting in a less complete burn (loss of power and increased emissions). That's another reason why you don't want to mill the heads much at all.

"Typical" high-performance engine builds use squish clearances of 0.025 to 0.030" cold. That's with 4340-type performance steel rods. Simply ratioing the modulus of elasticity between 4340 and Ti 6Al-4V (I don't know what Ti alloy Honda used so this is an educated guess), would change the minimum common 0.030" squish clearance with 4340 rods to 0.050" minimum with the Ti rods. That's because the Ti rods will stretch more and you therefore need more clearance.

That way I knew I had about 0.050" squish clearance at cold conditions when it was all said and done on my engine.

 

[MotorMouth93]

Thank you @Mac Attack this is extremely helpful. I'm thinking I'll use the 0.045" head gaskets to be on the safe side, as the saying goes, "Clearances too loose and only you know it, too tight and everyone knows it."

Wiseco recommended 0.003" for their 4032 pistons as well.

 

[Honcho]

Thank you @Mac Attack this is extremely helpful. I'm thinking I'll use the 0.045" head gaskets to be on the safe side, as the saying goes, "Clearances too loose and only you know it, too tight and everyone knows it."

Wiseco recommended 0.003" for their 4032 pistons as well.

+1

Amazing explanation and why I am NOT going to touch my short block other than to clean the deck surface and heat bolt threads! John, how did you get those cardboard inserts out of the cylinders without spilling all of the debris into them? I really like your idea, but want to get a sense of how you did it.

 

[MotorMouth93]

I used a shop vac to suck up any loose debris then used the suction from the shop vac to pull the pieces of cardboard straight up and out of the cylinders, then wiped off the remaining grease with a clean paper towel.

But yeah I've about reached the conclusion that I should have just left my short block alone, slapped on some new graphite gaskets, and run it until it wouldn't go anymore. The bottom end is a nasty can of worms to deal with.

 

[Mac Attack]

+1

Amazing explanation and why I am NOT going to touch my short block other than to clean the deck surface and heat bolt threads! John, how did you get those cardboard inserts out of the cylinders without spilling all of the debris into them? I really like your idea, but want to get a sense of how you did it.

When you do pop the heads off, please measure where the squish pads on the pistons are in relation to the deck using the method I described above! We know that the standard OEM compressed HG thickness is 0.030", so I have to believe that the OEM pistons sit down below the deck about 0.020" in order to maintain a squish clearance of around 0.050". While the SM allows you to resurface the heads up to a max of 0.008" and reduce the exhaust squish clearance, it doesn't allow you to surface the block and reduce both intake and exhaust squish clearance.

John - I would not run less than the 0.045" thick HG. In fact, until you confirm where exactly, a perfectly centered piston sits relative to the block deck using the method I described above, I would probably recommend the 0.051" thick gasket. The reason is because if your centered piston is indeed poking out 0.003" and you use a 0.045", the intake squish will be 0.042" as you noted. That's a bit less than the minimum 0.045" clearance I know from a truly professionally-built engine C-series engine with Ti rods. If the 0.003" poke was worst-case with the piston rocked over, then, yes, I'd say the 0.045" thick HG is fine.

Also like you said, I'd rather have a bit more clearance than not enough. That applies to bearing clearances, ring gaps, etc....

 

[MotorMouth93]

I agree with the theory, but SoS has built quite a few motors using their Wiseco pistons which have a compression height of 1.192" as far as I know and using the 0.030" head gaskets and I've never heard of anyone having issues with the pistons smacking into the heads. So assuming the 0.003" number the shop gave me is the piston rocked over worst case scenario, that would put the flat piston about 0.010 below an unshaved deck for a quench height of about 0.040".

I've seen the number 0.050" thrown around quite a bit for use with aluminum rods which have quite a bit more stretch and thermal expansion than titanium, and steel rods can go down to about 0.030 as we discussed earlier, so it doesn't seem too far fetched that titanium would be in the middle somewhere, and then a bit higher for more extreme power/rpm builds like yours.
@ScienceofSpeed do you have any information about the factory quench height so we don't have to sit here and guess?

But anyways...

I've opted to have ARP rod bolts installed in my rods, and since I don't trust anyone local to me I just drove everything back to the shop near DFW that did the block work to have them pressed in and resized. I don't know what I was thinking not having it done in the first place, but it's cheaper to deal with the hassle now than it is to deal with a rod bolt letting go at 8k rpm later. I'm hoping those will be done this week so I can spend my Thanksgiving break in engine assembly heaven, but until then I'm back to not having much to do.

So to fill my time I decided to try to convert some scrap 3/16" titanium I have into a pedal cover set. I've only done the dead pedal so far but I'm really happy with how it came out and will do the others as well. It's a perfect match for the TI Zanardi shift knob and my handbrake handle. I bought a set of autovation aluminum pedals second hand a while back but ended up not using them since I don't have any aluminum accents in the car, so I'm just using them as a pattern to base mine off of.

Pardon my messy car, it's been sitting for 5 months at this point. The only thing I'm not happy with is the autovation hardware, so I'm going to swap that out for black allen screws.

My fabrication facilities are limited to say the least. I cut the part out with a jigsaw, took care of the finer details with a grinder, then used a file to smooth it out. After that I drilled pilot holes with a very small bit on a drill press, then jumped up to final size. Once the holes were drilled, I blasted the part with steel shot to get the surface finish, then used a countersink bit to cut the chamfers around each hole. My previous experiences trying to drill titanium were pretty bad but I think that was mostly due to trying to do it with a hand drill. Once you find the sweet spot for drill speed and pressure it cuts like butter.

 

[Mac Attack]

I agree with the theory, but SoS has built quite a few motors using their Wiseco pistons which have a compression height of 1.192" as far as I know and using the 0.030" head gaskets and I've never heard of anyone having issues with the pistons smacking into the heads. So assuming the 0.003" number the shop gave me is the piston rocked over worst case scenario, that would put the flat piston about 0.010 below an unshaved deck for a quench height of about 0.040".

I've seen the number 0.050" thrown around quite a bit for use with aluminum rods which have quite a bit more stretch and thermal expansion than titanium, and steel rods can go down to about 0.030 as we discussed earlier, so it doesn't seem too far fetched that titanium would be in the middle somewhere, and then a bit higher for more extreme power/rpm builds like yours.
@ScienceofSpeed do you have any information about the factory quench height so we don't have to sit here and guess?

But anyways...

The difference between our pistons and the standard Wiseco is the ceramic dome coating thickness. Like I said above, you must have a pretty thick coating.

Before you buy and install your HG's, I would make sure of the nominal thickness your ceramic coater applied to the pistons and make sure to re-measure them again using the method I outlined.

When I posted earlier I had 0.050" squish clearance, that was actually measured. Because of the original machinist f^%$ up, I *think* about 0.02" total was removed from my block deck to correct gouging and the non-even surface. So, with a coated piston, the same 1.192" compression height as you and the other standard Wiseco piston users, I would say my effective HG thickness was 0.030" or even less.

BTW, the Wiseco piston specs that SOS carries comes courtesy of FXMD. They originally worked with Wiseco to develop what we're using now. :wink:

 

[MotorMouth93]

When my block is back together I'm going to measure it all out, but in the meantime, and at the risk of beating a dead horse, here is a purely theoretical discussion point:

I believe the factory deck height is 8.720", the stroke is 3.071", the rods are 5.986", and the combustion height is 1.192".

8.720 - 5.986 - (3.071/2) - 1.192 = 0.006", then add on the 0.030" for the head gasket and that brings us to 0.036" theoretical clearance using the typical Wiseco pistons.

If we modify that to account for my deck being shaved 0.008" we get a deck height of 8.712, so that becomes 8.712 - 5.986 - (3.071/2) - 1.192 = -0.002", which means the piston is poking out 0.002", which is very dang close to the 0.003" the machinist measured and pretty much bang on if you add another 1 or 2 thousandths for a typical ceramic coating thickness.

According to the machinist the ceramic coating is nominally around 0.001".

 

[Mac Attack]

I don't think it's beating a dead horse if this level of detail has only been discussed on Prime in one other thread. That thread was from Stevon where he gave the deck height range of 8.720" and the same 0.008" shave as allowed for the heads.

I didn't have that info at the time of my rebuild, and since I hadn't measured it when taking it all apart (it was carboned up pretty well anyways), I could only go by my dynamic sim calculation, final measurement, and a quick sanity check as described previously by ratioing the rod elastic deformation from what's commonly used.

Finally, I reached out to the one other person that truly knows these engines and he used a 0.045" thick compressed HG with Ti rods and the measured piston flush with the deck. For a similar build, I wouldn't go less than that, but that's just my opinion.

Anyways, yes, it certainly would be nice for our theoretical discussion to confirm the deck height range and OEM piston combustion height. Because, we do know the stroke is 78mm and the nominal rod length is 152mm. Throw in another 0.001" to 0.002" for clearances, another 0.001" for coatings, etc.

But, I do know that OEM isn't optimal after lookng at combustion paterns. That's the reason why I asked you in the beginning of your engine build for a picture of the heads when they were removed - So I could see the combustion chamber and read the patterns to see how they compared to others I've collected and analyzed over the years. :smile:

 

[MotorMouth93]

Another interesting data point is that pretty much all of the CP Carrillo NSX pistons have a combustion height of 1.184", so a full 0.008" less than Wiseco.

We should see about getting an engine block specs and rebuilding page set up on the Wiki, I can help when I get all this done with, right now the only way to get the info is to scour through long, old threads looking for crumbs.

Based on what you've seen from burn patterns on heads, do you think the OEM configuration isn't tight enough or trends towards too tight?

 

[Honcho]

FWIW, I will try to measure my stock block and pistons once I have it apart and report back. I don't have very fancy precision tools for this, but I'll try!

 

[MotorMouth93]

I ended up selling my Spoon mirrors instead of having them painted. After looking at more photos I decided it's just not an aesthetic I like very much, I didn't lose any money on them though so that was nice.

I went through my main caps again and made sure all of them were clean and had the corners rounded off nicely, I'd done it once before but realized I could do a better job. When they fail they tend to crack through the oil hole in the middle so I made sure to get that area nice and smooth along with the outer edges along the arc and the flat top part. The scratches you see are very fine scratches from the machinists bore gauge.

I also picked up a set of JDM NSX-R pedals on Facebook so I got to work installing them. The clutch and brake went on easy, just pop off the rubber covers, pop the R cover on, drill 3 holes, and install using the provided rivets. I didn't need any of the drill bit 90 degree adapters or anything since both my clutch and brake systems are more or less completely depressurized so I was just able to push the pedals down while I drilled them.

The gas pedal proved far more challenging. The standard NSX gas pedal is a metal cup welded to a stick with a plastic cover. The R pedal is a similar (but different to account for RHD vs LHD) stick, similar but different cup, a metal plate welded to that, then the aluminum pedal cover riveted to that metal plate. You can't just swap the entire R pedal over because it would move the gas pedal over too far to the right. Just riveting the aluminum cover to the cup sort of works but then you have rivets poking through the back of the pedal and getting in the way of the stopper and it's just a lazy way to do it. Swapping the "cup" part over would be ideal but would require cutting and welding on the existing pedal which would require it to be removed from the car. However, swapping just the metal mounting plate to the USDM pedal is relatively straightforward.

The "cup" with the plastic cover removed.

The R pedal assembly with the aluminum cover rivets removed. (and one extra rivet I did as practice)

The R pedal is slightly different shaped, so to account for this I cut the corner off the existing pedal cup with a dremel then filed the edges smooth with a grindstone bit. The plastic cover can still be put back on with no visible changes, not that I'd want to put it back on.

Then I cut the welds holding the metal mounting plate to the R pedal and found that with careful placement of rivets, they would not interfere with the flush mounting of the aluminum cover. You can see here by the extra set of rivet holes that I got a bit cocky and did not follow time tested "measure twice cut once" rule here, and got to drill the plate twice, the part also got pretty scratched up during the weld cutting process. Doesn't matter since it isn't visible though so I'm not going to lose any sleep over it.

Everything together and vacuumed, and IMO turned out great. I'm really glad I got rid of the rather ugly autovation pedals I was thinking about using instead.

I was also finally able to source a JDM mainshaft 4th gear - possibly the last one available until the current backorder ends - so I won't be pulling my transmission again later to swap the gears and rebuild it, and instead I'll knock that out in the next few weeks. Thanks to @Bense for pointing me in the direction of someone who had one.

 

[MotorMouth93]

Just a quick update, I got the crank and pistons back from the shop since changing the rod bolts did not affect the rotating assembly balance, so I spent a few hours yesterday finalizing my main clearances. The #4 clearance was at 0.0010 with the factory bearings (black/black) so changing those out with brown bearings widened that out to 0.0015. My final clearances on the mains are 0.0015, 0.0017, 0.0017, and 0.0015 which is pretty much perfect. Now I’m just waiting on the rods to be resized and I can get this engine buttoned up for good. I think the car should be back on the road for break in by the end of the year.

I had my injectors professionally cleaned and rebuilt and they found that 2 of them had poor spray patterns and were flowing at about 80% capacity but they’re all pretty much perfect now.

 

[Honcho]

Those clearances are great! Nice work!

 

[Mac Attack]

[MENTION=33247]MotorMouth93[/MENTION]

Cool - Does that mean you're building the bottom end yourself?! You can do it!

Just like radiusing the edges of the main caps to reduce stress risers, I also recommend doing the crank edges too. As I'm sure you've found out, some of them are sharp enough to cut you. There have been more than a few crank failures in the C-series to not go ahead and do it while it's apart. Just tape the journals with some good tape so you don't accidentally scratch them. Don't worry about the lost weight, and therefore, balance.

Another thing I just thought of - Did the machine shop thoroughly clean the crank afterwards? If they didn't TIG the internal oil journal passageway balls out and then clean/insert new balls, I'd have them do it for peace of mind since they cut into your steel crank. One of the main causes of engine failure after a rebuild is residual contaminants that weren't properly cleaned out.

Even when the machine shops returned my parts "clean" I always cleaned them again a few times with Dawn through a pressure washer, then liberal WD40 and air compressor....

 

[MotorMouth93]

Yeah I'm assembling it myself, which is why I haven't sent your piston ring compressor back yet. While the clearances with the factory color bearings were "okay" one of the mains was at 0.0010 which is too tight for my liking and I also decided I wanted ARP rod bolts. I'm still waiting for the rods, the shop has been pretty busy lately.

I cleaned everything myself since taking it apart after the shop assembled it and they did a great job cleaning it.

 

[NSXF1]

Excellent Build!

This is the reason I bought another NSX after a 10 year absence. OCD like minded people who make huge contributions like this.

Outstanding work MotorMouth93. Found this and read it all in one sitting.

Got a little queasy when you described the oil pan dent and connected all the dots. Definitely felt your pain there.

Still, your car is very lucky to have you as an owner.

Excellent work. Keep it going.

 

[MotorMouth93]

Another delay, I got the rods back today, started measuring them, and the oil clearances were coming out to be 0.0050ish, which is more than double the maximum allowed clearance in the service manual. The rod housing bores all measured out at 2.0905ish. I did a bit of digging and found that my 1993 factory service manual lists the bore size as, I quote, "53mm (2.09 in)".

The problem is, 53mm is 2.0866 inches, not 2.0900 inches. For some reason the service manual rounded that value rather than giving the exact inch measurement like they do pretty much everywhere else, the shop had the manual and resized the rods using the inches number. So they'll have to be resized again. I'm not sure if that's even possible though since they bored them out a solid 0.0025" too big so this might be a fairly substantial roadblock. I hope I don't have to get aftermarket rods, but if my rods are toast I don't think I'll have another choice.

There go my plans of getting the engine back together before the end of the year, oh well.

 

[Honcho]

Another delay, I got the rods back today, started measuring them, and the oil clearances were coming out to be 0.0050ish, which is more than double the maximum allowed clearance in the service manual. The rod housing bores all measured out at 2.0905ish. I did a bit of digging and found that my 1993 factory service manual lists the bore size as, I quote, "53mm (2.09 in)".

The problem is, 53mm is 2.0866 inches, not 2.0900 inches. For some reason the service manual rounded that value rather than giving the exact inch measurement like they do pretty much everywhere else, the shop had the manual and resized the rods using the inches number. So they'll have to be resized again. I'm not sure if that's even possible though since they bored them out a solid 0.0025" too big so this might be a fairly substantial roadblock. I hope I don't have to get aftermarket rods, but if my rods are toast I don't think I'll have another choice.

There go my plans of getting the engine back together before the end of the year, oh well.

That sucks! Any chance you can run them with thicker bearings to take up the slack? You might want to talk to Kaz or Shad.