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Nippon Denso Honda Crx Oem Alternator Rebuild


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#1
greasemonkeyreborne 5x1g's

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    • Drives: 9 crx's: #1 228k 87si beater, #2 concours 25K, #3 108K 87si, #4 98K parts car, #5 213K 87si parts car, #6 84 straman, #7 86si 150k #8 67k parts #9 129K si for straman conversion
My experience w Denso OE alternators between the crxs, integras and lexis I have own/owned, appears these last 150-200k miles. Most common failure 1) brushes 4x, 2) bearings 2x, 3) rectifier/diode. my lifetime totals for OE factory installed alts between all the family cars.

Had my Beaters alt go out around 160k?? bearings would seize, squeal belt on start ups if i let the car sit too long (Michigan/Long Island salt). I installed a used OE ND w 100Kish mile. That one took me from 160 to 252k (160k total miles for this particular alt). Failed at 252k due to worn brushes. I didnt' like the slip ring groove, so replaced w the 129K crx's alt.   then i blew the rectifier running the head lights, front/rear wipers, rear defrost, heater fan on hi w my radio turned up idling at a light w brake lights on. Pushed the 34 year old alt to its limits.  then I installed the 67K alt w NOS brush assy.  Had been using that one since.

IMO, Hondas reliability hey-day were the 80s. I want original NDs to maintain that reliability.

My first car out of high school was a Lee Iococa era early 80s car. did the free alt replacement plan. after replacing 3 alts on that plan, i sold that POS and bought the beater in 1993. Reading recent posts on recent rebuilds, things haven't changed. Remanufactured alts are a last resort for me. My most confident plan moving forward has always been to find original Honda parts and use/rebuild myself.

My base alternators are 5 red labeled OEM CHA18 NDs for the SIs 1) 67k installed to beater last year, 2) 104k, 3) 129k from crx#9 - for the Straman conversion, 4) 252k beater (98k from crx#4 donor installed to beater around 160k, about at 160k now) and 5) 150k ish from random junkyard. Theres more on my spare engines and cars in storage to sort out

51851614087_eb7995ce42_c.jpg
 
 
I stumbled across 2 Honda blue labelled remanufactured in japan NDs for 88-91 crx at junkies over the years. one was actually installed in an 86crxsi w 150k. the alt was brand new. other was on a 91 crxsi, that one turned out to be almost new. i grabbed another off a1988 integra. Point here.... the rectifier, armature, bearings and brushes are a match for the 1G crxsi. These are either spare parts, or if i can get rpr guidance, maybe w the right pulley, I can used the for more amps in the future?

REBUILDING 4 CHA18 35 yr old Nippon Denso OE alternators.......

Ran the alt tests on my 87 haynes manual pages 25-40 to 25-43 tested rectifier, rotor and coil case. Since its in the manual, I wont cover it here. Assuming we all have that manual
 
51851619422_a952f7c90b_c.jpg
Tapped the top of the triangle back and forth to loosen the halves.  Then wacked it to one side enough to get a screw driver and hammer to separate a gap.  Then worked screwdrivers along perimeter until it came apart.
 
 
51853242010_936b5d6c5b_c.jpg
Since I was reusing the bearings, I pressed them out.
 
 
SLIP RINGS
Was concerned about grooves worn into the slip ring by the brushes. Whats the service limit of the copper?? I measured the rings off my 2 NOS Honda rebuild alts. Slip ring OD is .567. Measuring the unworn portion of my used NDs, they all measure .567. I sawed 2 rings down into the copper through to the ID. (in a non destructive location on the edge). This tells me Honda OE slip rings are .050 thick. I can monitor remaining thickness after i file them down. Reusing ground slip rings means brushes wont last as long as they have to extend further. Thinner copper and heat generation at contact point, I have no idea if I'm creating a problem here, speak up if anyone has experience here

They make a slip ring rebuild sleeve. you chisel away the old slip ring and press/solder the new one on. The 88 teg alt was a reman where they did this. those rings are .050 think as well, w varying OD. Keeping these on hand for use in 20 years

51852583591_0ff1725c55_c.jpg
 
I rotated the rotor and filed the tops off the grooves.  Each ring wears differently.  Not sure if its spring tension?  Or electrical loading?  The 4 alternators ranged from .550 - .565".  Measurements across all 8 total rings.  If '050" thick, (.550-.567)/2 leaves about .009" of .050" worn, or 20%.   I have not idea whats safe min thickness....    Interestingly, the alts from salted/dirty climates wore the most.  Clean alterators had the least amount of wear.   2 other family cars had brake fluid/oil leak into those alts.  Oil made brush carbon stick and exelerated the wear.
 
 
51851620407_e793d27821_c.jpg
If you look closely at the slip ring, you can see my saw cuts.  The brushes do not contact that spot.

BEARINGS
I have several sets of Honda bearing. I used dental picks to carefully remove the seals, exposing the bearings. I opened 8 bearings and damaged 2 of the 16 seals removed.  I inspected them w a jewelers glass to be sure.  seals Pix below is an NOS bearing from my storage of 20 yrs. Compared to the 252k bearings. Grease still reasonable on the old NOS. 252k was dry and crumbly.   I slid both bearings back on the shaft and wiggled them, spun them. 252k had slight wobble. Could barely hear bearing rattle w lack of grease. I regreased the 252k bearing as the race was very clean. They actually felt pretty good. Feeling these old bearing in good shape, and the seals were very pliable,  I regreased and reused all of my original Honda bearings (except the one w damaged seals), cleaned and regreased. Theres no way these bearings will cause the rotor to interfere w the coil. I see little risk. Will reinstall the rebuilt 252k alt to the beater as my proof of concept and put back in service this weekend
 
51853242895_e62bf55dd1_c.jpg
GREASE
Im taking path of regreasing my bearings as old grease has dried out. Also to refresh grease from aged NOS bearings. Need a sticky grease. hi/low temperature range for high speed rpm. Chevron SRI and Mobil polyrex EM greases appear to be the choices- designed for electric motors. I bought the Mobil 2 years ago from granger for $11/tube. -20 to +350f service range. Key is not to over grease. It will sling grease out of bearing, onto alt. Im using the NOS bearings as my quide here


CONTACT CLEANING
i used a dremmel w a mini wire brush to lightly clean all electrical contact points. this the undersides of all the screw heads.  I used hot/soapy water to scrub the rest of the components to get the dirt/grease off to keep it cool while running.  Decided not to use chemicals/power wash to not damage the coiling and epoxy holding the wiring together.

PULLEY
Interesting here. The NOS's measure 2.250 OD off the ribs. Some of the original NDs measured 2.235, 2.230, 2.250. Apparently, Honda varied diameter for some reason. One of the 2g crx measured 2.150. Smaller pulleys spins faster, generating more current. Will be a later project to play w pulleys and the 2g crxs alts to pump my amps. These cars were made when speed limit was 55mph. Driving 80mph sustained might be a long term problem?

VOLTAGE REGULATOR
Cant reallly test til on the car

TESTING
Went to Oriellys w my alts during the last rebuild. They had a hard time getting the correct connector. The CHI18 designation helped him locate the correct connector. Will repeat to have them test my rebuilds

RISKS
Reusing original 35yr old Honda OE voltage regulator and diodes.  I have no idea how long these will last. 
 
Reusing rotor and stator as is.  I really dont see a rish here.
 
Bearings, I inspected the balls/races and seals w jewelers glass.  Seals were stretchy/pliable.  I really think these will be fine.

Bearing seals: in some, i nicked one of the double seals. its the inner seal (small diameter) it wont allow grease to fling out, but might allow moisture in. felt low risk
 
I pack an extra alt on out of state trips. Im not concerned. I'd rather take the chance on 80's honda electronics vs Chinese POS replacement parts until I"m proven wrong.  The 252k rebuilt alternator will prove if my theory is sound. New NOS brushes.

OBSERVATIONS
 
The 88 teg alt was rebuilt aftermarket.  It was tight, but the bearings were chinese.  The seals were a stiff plastic crap.  I don't see how they would last long.
 
The 88 teg was also missing the dust washers on the large bearing leading to potential remature failure.
 
The ND out/small bearing grease was much darker.  I believe the carbon entered the sealed unit. As the large bearing was clean.
 
****** This teaches me I must replace any sealed bearing in my car thats original.  All the 35 yr old ND's grease was dry.   Now I know what a dry bearing "hum" sounds like to identify before I get a hard failure in the future *******
 
Reassembled w NOS burshes and reused a Honda rectifier off the 2G CRX alts to maintain original. Very few parts required to rebuild.
 
Is it worth it to open the bearings to regrease,...  NO.   The bearings seem fine and Ill do it again if I have the time.
 
Reinstalling the 252k rebuilt to the beater.  Removing the 67K working alt to regrease the bearings and keep as a spare.
 
Keep ya posted as I clock the miles on these.  Not saying these are better than Autozone, but I feel more confidant based on the horror stories I hear w free, worthless replacement warranty....
Keepin' it OEM

#2
CSPCRX

Amazing project and details.


Victor
86 K24 Powered CRX SI (SMF Solo2, HPDE-4 NASA & TA-A Time Attack

85 CRX DX totally original
07 Harley FXST Softail

2021 Tacoma Tow/Daily


#3
greasemonkeyreborne 5x1g's

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    • Drives: 9 crx's: #1 228k 87si beater, #2 concours 25K, #3 108K 87si, #4 98K parts car, #5 213K 87si parts car, #6 84 straman, #7 86si 150k #8 67k parts #9 129K si for straman conversion

We'll see how these last down the road and if its worth the risk not replacing the rectifiers and voltage regulators...  Keeping my fingers crossed.   Big lesson for me having these other cars sitting around 20 years...  I need to replace/regrease all the bearings!   Glad I got into this before I burned out bearings.

 

Just uploaded the pix as I'm completed the 4 rebuilds a few hours ago..    

 

I used a stethescope to listen to the bearings on the car.  If you hear a reasonable "hum", get to those bearings


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#4
greasemonkeyreborne 5x1g's

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    • Drives: 9 crx's: #1 228k 87si beater, #2 concours 25K, #3 108K 87si, #4 98K parts car, #5 213K 87si parts car, #6 84 straman, #7 86si 150k #8 67k parts #9 129K si for straman conversion
removed the 67k alt from the beater last night. refurbished it. had nos brushes in that from last year. just cleaned and regreased the bearings.. put it back together. Looks like ive added driven 20 k miles to this one. now an 87k alt.

reinstalled 252k refurbished alt w 160k ish miles. this is my highest mileage alt. beater has 271,800 miles. keep ya posted on how long this lasts. Reliability clock starts here. basically, itll be a VC or diode failure since those parts are original, oldest.

please share ur alt longevities. im assuming im on a better path than buying an aftermarket rebuild???

Ive refined my bearing seal removal. ive been placing the pick on the inner race. drop it backwards 1/8, then angle down and push really hard toward the center, trying to touch the ball carriage. key has been to do this in one movement and one location to minize seal nicks. pry gently until i can get a second pick. then pull up. w a jewelers glass, i can see a tiny knock every now and then. i do deform the metal seal backing slightly on some. i reflaten as necessary. these bearings retailer at honda for $35/ea. i had bought a bag of 10 small 398Ts a few years ago for $6/ea. appears now $12+.. PITA, but i had the time and curiosity.

ive added grease to lubricate the dental pick - it pulls/stretches the rubber.. and i sharpie mark that location where i insert the pick - faster to inspect.
Keepin' it OEM

#5
CSPCRX

74,800 miles on the 85 original.

 

I remember, back when I had the EW in my 86, I kept having to replace them.  Thankfully I was getting the lifetime warranty units from Checker Auto.  But I got really good at swapping them out in the dark even, knew just how to rotate it to get it past the rack and axle.

 

had a similar issue with the distributor.  Original let go, only place I could get a replacement from was BAP.  Had two have bearing failure, one even sent parts to the side of the housing.  Finally got one to last then the B16 went in.  Funny I just had to replace the distributor on the B16.  Was getting some odd starting and running issues.  Pain with the JDM B16a OBD0 is there was never one here in the states.

 

Kind of looking forward to K24 swap in the 86 for the fact there is no distributor and all t

he accessories have a US equivalent 


Victor
86 K24 Powered CRX SI (SMF Solo2, HPDE-4 NASA & TA-A Time Attack

85 CRX DX totally original
07 Harley FXST Softail

2021 Tacoma Tow/Daily


#6
greasemonkeyreborne 5x1g's

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    • Drives: 9 crx's: #1 228k 87si beater, #2 concours 25K, #3 108K 87si, #4 98K parts car, #5 213K 87si parts car, #6 84 straman, #7 86si 150k #8 67k parts #9 129K si for straman conversion
i heard these cars eat dizzys. i’m still on my original ( 272k) minus the ignitor i replaced pre emptively.

k24 sounds like a much better deal
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#7
greasemonkeyreborne 5x1g's

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    • Drives: 9 crx's: #1 228k 87si beater, #2 concours 25K, #3 108K 87si, #4 98K parts car, #5 213K 87si parts car, #6 84 straman, #7 86si 150k #8 67k parts #9 129K si for straman conversion

Opened up the 6th red labelled NP 35yr old alternator.  This one came off CRX#3 (Mad Max).   I put like 500 miles on the car when I bought it in 2000.  Had been in storage.  The belt would squeal at start up.  I started it like 1-2x a year and assumed it was moisture in the bearings locking it up. 

 

Last night, we opened it and the PO must have manhandled the alternator to change the belt.  One one the cooling inlet fins off the stator housing cracked.  A small piece jammed the rotor (been this way since 2005 ish??)  I just cut the belt off back then as I wasn't driving it off the farm.

 

51928759929_3221141185_c.jpg​

 

This one was just like the rest.  Slip rings worn to .550 and .565 (outer/inner).   This was better than I'd thought.  I'd expected the northern salt exposure to cause more abraision and wear on the brushes.  The pulley OD was 2.230".  Its so odd Honda varied pulley diameters for the 86/87 models.  I don't think I have 85si alternators.  Maybe Honda changed diameters as the speed limits began to increase, maybe too high of RPM??

 

Bearings were dry.  I didn't remove the seals to inspect.  Saving that for another time as a have plenty of spares at the moment.  Additional evidence to grease/change any sealed bearing on our 35 year old cars.

 

This project gave my son experience using the Helms manual w my volt meter to test the components.  Everything else checks out fine.  So I"ll use this one as spare parts to rebuild others as I'm happy to have a set of original Denso Diode/volt regulator.

 

This one was a good example for Max.  Since it came from a salt environment, we broke off 3 screw studs.  Since the stator housing was cracked, It was ok.  Good to teach my son how bad salt corrodes aluminum and guals the threads.  I only broke on screw head on the other five rebuilds the other month.  Was lucky

 

Using one of the other 5 alternators rebuilt to instal into his car, MadMax.

 

 

Update on my quality of rebuilds.....  Well, not enough time yet to tell.  I reinstalled the alternator I had in my beater.  I've labelled that one 252K.  So it had 252K, regreased bearings, new honda brushes and filled down copper slip rings. Have about 500 miles on it since reinstallation last month.  So far so good.

 

Anyone use 2G CRX Alternators???   If anyone has experience upgrading their alternators w a 2g CRX, please share.  I have 2 Honda factory rebuilt used alternators I pulled from junkyards.  One came off an 86CRX si.  The other came off an 88 2g CRX.  Both have same part numbers, but don't cross reference w 1g CRX.  When I pull the peice parts diagram, appears the voltage regulator and stator assemblies are different, but most other parts identical.  those alternators were practically new as the brushes were worn less than 20%.  Since one was on the 86 CRX SI, I'm thinking they are compatible.  But pulley size might be different making RPM changes as 2G engines differ from 1G.  Anyway, speak up if anyone knows if these will work?  I'm guessing stator wiring is a little different as well???   I'll have to get to the pulleys again and compare differences and run an RPM delta calculation


Keepin' it OEM

#8
CSPCRX

Never heard of using one off a second gen CRX.  The D series engine wasn’t all that different from the EW but I don’t recall ever hearing of cross compatibility.

Great write up and props for saving these parts.


Victor
86 K24 Powered CRX SI (SMF Solo2, HPDE-4 NASA & TA-A Time Attack

85 CRX DX totally original
07 Harley FXST Softail

2021 Tacoma Tow/Daily


#9
Dear_Boss

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great post about the original alternator. Awesome to see the rebuild process.

 

Since i retrofitted mine with an aftermarket internally regulated version i believe i have 2 original alternators sitting around. Not sure of their condition but maybe they have some parts that you could use in the future.

 

If i find them you can have them if you want them, DM me.



#10
greasemonkeyreborne 5x1g's

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DB,  I'll PM ya.  Yes  I'd like to buy them off ya...
 
I was idling in my driveway last month, and the battery light came on....   Crap!   So I swapped it w another rebuild.  Took this one apart and it was the rotor that failed!!!  I purposely used the press to gently take everything apart.  Can't believe I damaged anything.  But some of the rotors had the epoxy  coming up where the slip ring wires are connected to the face of the rotor.   I'll root cause it and report back.
 
Bums me out.   I was hoping to have more reliability out of these than aftermarket rebuilds.
 
More to come
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#11
greasemonkeyreborne 5x1g's

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I pulled apart the 252k alternator that failed last month on CRX#1.   I ran through all the Helms tests.  All components good except the rotor.  The VR will need to be tested in the car when I put it all back together.
 
 
Here's the failure.  Apparently, the rotor windings shorted and burned a wire on an outer winding.
 
 
52065302931_479e07b7b6_z.jpg
 
You can see the black carbon burns on the windings on the side closest to the bottom of screen.  The top side is still painted electric orange.  Theres a wire that snapped when it shorted and is handing at the screw driver tip.
 
It had to have been an instantaneous vaporization.  There was evidence of carbon flash on the stator side.  It left an outline of the magnet pattern.  Interesting.   Stator tested fine, but this could weaken the insulation on those windings.
 
I don't deal w electric motor rebuilds.  Googled rotor failure common causes....  they say break down of winding insulation.  overheating.  rotor shorting to stator housing.
 
I didn't feel any dragging of the rotor when spinning.  So I'm ruling out reuse of old bearings causing tolerance problems as the moment
 
I'm guessing when this alternator blew the diodes previously, it overheated some and degraded/accelerated the rotor windings causing the failure.....
 
Or, the winding insulation just aged enough to cause the short and it failed.
 
This is making me think  rebuilds fail so much from autozone and the like.  Maybe the rest of the parts are close to failing????  rebuilds just slap together new brushes, grease the bearings and go.
 
Theory for now.
 
 
 
Next phase:   I examined MadMax 108K red labelled alternator.  I have no idea how this happened, but both sides of the housings were cracked.  The crack misshaped the stator housing, causing the belt to squeal from rotor locking up.  I really thought it was a seized bearing issue.  This proves it wasn't
 
52065538274_039a94fb02_z.jpg
 
Theres corrosion inside the crack, so its been this way for a while.  
 
All the internal components tested great.  Since housings cracked, I'm using the internal parts to rebuilt the others as needed.  I scavenged the rotor from MadMax and rebuilt the 252k alt again.  I did notice a little bearing noise on the bearing closest to the slip rings.  I could feel a rough spot.   I replaced that bearing w a new japanese NOS bearing from stock.  I didn't have time to open the bearing to see whats up.  I had opened and cleaned the bearing during the original rebuilt.  I'm suspecting the bearing took the surge and may have arc'd through it causing the rough spot(welded)???  I'll pull apart later and see what happened.
 
Going to put the (second rebuilt version) of 252k alternator to CRX#1 and see what happens.  
 
At this point, I need to understand if I can really reuse these older alternators.  I suspect if an alternator has an overheating/shorting problem, the windings may no longer be reliable.  I've documented the rebuilds.  I can track the failures and see patterns.
 
52065539174_5afd216a18_c.jpg
 
252kon left.  MadMax #3 on right
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#12
greasemonkeyreborne 5x1g's

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    • Drives: 9 crx's: #1 228k 87si beater, #2 concours 25K, #3 108K 87si, #4 98K parts car, #5 213K 87si parts car, #6 84 straman, #7 86si 150k #8 67k parts #9 129K si for straman conversion
I reinstalled the 252k alt over the weekend. fired up the engine and it worked. The VR was fine. In play at 274,541 miles. Let the science project continue. 50 miles clocked and counting

The more I sleep on this, im thinking the insulation on the windings has a life span (not infinite as I had hoped coming from Honda) No idea what it is. clear epoxy?? And theyre just going to fail. I see nothing I did that caused a short to vaporize the windings.... but im not an electric motor expert


Other thing, my beater sometimes idles low.. 400-500rpm. thinking a vacuum leak or something in emissions control box?? wondered if low rpm added more stress to alt?

We havent the been using the extra fog lights. No high powered radio
Keepin' it OEM

#13
CSPCRX

Usually a vacuum leak would cause a high idle.  Hard to say with the way all the valves work in that box.  I ditched mine years ago on my EW3 and never had any emissions issues.


Victor
86 K24 Powered CRX SI (SMF Solo2, HPDE-4 NASA & TA-A Time Attack

85 CRX DX totally original
07 Harley FXST Softail

2021 Tacoma Tow/Daily


#14
greasemonkeyreborne 5x1g's

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    • Drives: 9 crx's: #1 228k 87si beater, #2 concours 25K, #3 108K 87si, #4 98K parts car, #5 213K 87si parts car, #6 84 straman, #7 86si 150k #8 67k parts #9 129K si for straman conversion

52719044290_8e40423972_c.jpg

 

Cleaning/sorting out some parts.  Came across my original alternator to the Beater.  Looking forward to taking this apart again and reinstalling to the beater


Keepin' it OEM