From what ive read/researched/been told, ideal cylinder taper for a honda motor should be 0000000 from top to bottom. this is a b18c1

I just had my short block bored and honed, doing a stock rebuild, stepping it up to 82mm pistons.

ive finally gotten around to checking things out before i go cray ordering, check my cylinder taper compared to the pistons (3.2275"). i had requested anywhere between .0011-.0013 for p2w.

Checking my bore, all the cylinders are consistant, BUT go from 3.2280-2.2320 from top to bottom. WTF, is this ok?

 

So you have 0.996" of taper? Lol

Might want to check your dial bore gauge

Assuming you meant 3.2320 not 2.2320, 0.004" is still way to much taper...

Was it bored and honed with a torque plate?

Double and triple check your measurements and measuring devices, then go back to the machine shop and complain.

 

yea i did a rough check with everything. but if it seems that way in all four cylinders, i smell trouble. im just asking whyyyy!!!! why me!!! its bad enough this build is taking me forever, n now when i get to it to see this?

yea, i meant 3.2320"

i called him earlier because i also just realized im missing some of my oil pan studs, hopefully he will find them.

ill have to ask about the torque plate, which i suppose i should have asked before in the first place. This guy has so much work though and has such a good name, to do work like this im baffled.

and where should i go from here? its not like something like this can be easily fixed. i feel like right now i would have been better off with my bellmouthing motor with way less taper.

 

amen, brother. I spun a bearing in my h22 and decided to put in f-series internals (which I already had) because a build would cost less than buying another h-series. I was wrong....baddddd wrong..

 

To be straight forward with you, if it really is that far off, your only semi-cost effective option in my eyes would be to get it squared up properly and run a forged piston at about a 0.004" p2w if the shop doesn't want to help you out. I would not be comfortable pushing stock sleeves beyond 82mm.

My advice would be to take it back to the shop and get them to measure it with you watching and see what they come up with. Make them prove it's straight and true. If it really is that far off then they need to make it right by you; which would mean them covering the cost of another block and the associated machining with said block. If it really is a good shop they will have no problem doing so.

Now, your only hope is that it was bored and honed with a torque plate. The simplest explanation I can come up with for a torque plate is that it is basically a mock cylinder head that is bolted to the block during the boring and honing process to simulate the stresses associated with having a cylinder head torqued to the block. When you torque a head down it tweaks the block slightly. The torque plate approach was devised so that when the head is bolted down the block is straight and true, but when the head is not installed the bores are actually off because they aren't stressed so to speak. I don't know off the top of my head how far it can put a block off by, but it may very well have something to do with your situation.

Also, what temperature was the block when you did all of your measuring? Rough estimate.

It's not the end of the world yet. I know how you feel, lots of time, money, effort, and inconvenience because your ride is down. Everything will work out. All the headaches will be worth it in the end when you can beat on it and get some satisfaction.

I don't mean to discount you, but it probably is just an oversight on your part so don't freak out to bad yet.

Btw, the 0.003" of taper it had before is really no better in the grand scheme of things.

 

brother, you dont have taper in that cylinder, you have ****** funnel. Id take that thing the **** back immediately.

 

To put it mildly. Lmfao

 

If that's the case then you have .004 taper in that cylinder, which is still beyond the .002 OEM service limit. However depending on your bore gauge you may only be able to measure within an accuracy of .0005 which is what my fowler bore gauge reads.

 

^New sig**

 

lol i must be well known around here for the most quotable quotes :x

 

Ok. So i guess we will just have to wait and see whats said tomorrow. Im fairly certain my measures are accurate as well as my tools, though i went on the lower end on purchases because im only your beginning back yard mechanic.

i have this dial bore gauge
to prove its accuracy to myself in the beginning, i played around with the different mic lengths and the dial bore gauge, to see if this digital nonsense is accurate (which it was a very good amount of the time, and if it was off it was by a ten or 2 tops). i prefer being old school and getting dials with arms and such, but the digital is convenient. ive gotten pretty good and consistent at using both if i can say so for myself.

fingers crossed for some type of good news. will keep you posted

 

Lol double quote.


How many people acrually measure.
I know mine wasnt done with the torque plate or measured for taper but i will once the block is out.

 

Same one I have except mine has the optional secondary smaller head so I can measure rod big ends which are about 1.8".

 

Hey man. Sucks to hear about your build hang ups. Just so you do have a reference with regards to taper and torque plates. My block was honed with a torque plate on and I measured taper to be about .0008". I think what 98GSR said is your best bet for a good outcome. Take your block down there and have them inspect it with you. Bring your bore gauge also. Bring the spec sheet with you also.

 

progress report: thanks for all the advice. Spoke on the phone with my guy, he has no problem with me taking the block down and walking me through it. Will bring a spec sheet and my tools as well.

His explanation was that he may have used some generic torque plate (wasnt really sure what he said exactly over the phone, but that the 4 banger torque plates were pretty pricey and he didnt have em) and that he also used a torque plate on the bottom to imitate the girdle. When he was boring it out, he said the honing machine was skipping and not making contact at the bottom and thats the way it came out. I dont believe it, considering my numerous measurements prior showed that it was bellmouthing, and that both ends tapered IN while the middle was wider by around .0015. He said that the taper at the bottom wouldnt even get to the rings, otherwise he would have suggested stepping up to even bigger pistons. Regardless he wants me to be happy with the work, though how happy he'll make me is debatable. Also found my missing oil pan studs still resting on the decking machine so thats good.

Unfortunately, first free day i got to get down there is tuesday afternoon (hopefully). Just gotta not take no for an answer here, its clear to me the s*** is not satisfactory, but im still willing to speculate.

 

.0040" taper is not ok. .0020" is the f20c max limit for taper and thats for a stock rebuild and what a tech can call "ok" for warranty.

Im glad he is willing to work with you but if he knew of the issues, he should have confronted you prior to proceeding further. IF your measurements are right, id be concerned with doing business with him again as feeling the need to check your machinist work isnt exactly the greatest feeling in the world.

 

this thread makes me wonder how honest are the machine shops when they assemble your engines lol.

would they say anything if you drop it off and they assemble the block and be like here you go bro enjoy.

month later you have a smoking block and they say well sorry mang its not our problem anymore.

at least you measured.

 

You should not have to double check the work of a professional machinist, ever. I use "have" because all work done should always be spot on.

This guy is starting to sound like a hack to me to be honest with you. If the block was bored correctly, there should have been ZERO taper before it even went to the honing machine to be sized to the final piston to wall clearance.

0.0012" of taper is the absolute most one of these little honda engines can handle and still get an ok ring seal regardless of what the service limit is. It'll run with 0.0020" of taper, but it won't run well.

 

Funny you mention that, because it is exactly what happened to me. Paid a supposedly reputable machine shop to do a some work to a short block, and assemble it. Guess what, first race weekend out with that engine, it spun a rod bearing; $1500 well spent They said oh well **** you. That's when I said the hell with it and starting doing things on my own for the most part. I've since befriended what I would call a "class act" machinist who does great work and puts up with all of my silly little requests. Anything I can't do, I send to him.

 

its also great that shops dont give any warranty at all.
they say. we dont warranty race engines.
well any engine can be put under a race engine category. even a stock rebuilt b16z6 can be called a race engine by some.

but on the other side is the people that constantly beat on their engine thinking that its made of unobtainium like volverines claws... if customers were honest then shops would be too.

 

How can a machinist warranty an engine when there is literally a seemingly infinite number of ways the installer can slip up and cause an engine failure? Especially a "weekend warrior" type that doesn't build cars for a living and has very limited experience and understanding of how things work. I've seen improper installation of a clutch/trans destroy an engine and bend the crank, the wrong o-ring spin all the rod and main bearings, and one guy forgetting to open a valve completely destroy a $60k engine, but as far as the owner knew, it was the engine builders' fault. Then countless of man hours are wasted determining the real cause and culprit, only to be asked to "help out" and get the engine running again for an upcoming race. Warranties for race engines are financial suicide for a machine shop, HOWEVER, most shops that have been in business for awhile and have earned a good reputation have learned that if there is a mistake on their part, standing behind their work and fixing it will be better than telling the customer to get lost.

As for the bores, if this shop really can't get an engine out with less than .004" taper, they shouldn't be in business. If I ever have more than .0004" taper in a cylinder I honed, I would be embarrassed (except for maybe a Darton sleeve block). Now, that taper may decrease significantly once the torque plate and girdle are bolted up, most aluminum blocks will move ALOT. You may get it over to the machine shop and find that everything is fine, that the machine shop with all this experience actually knew what they were doing, and that you did not. This leads me back to my opening rant; wasted time and money.

 

progress report: so i actually went to the shop tuesday afternoon. vented my frustrations. he didnt question a single thing i said, as if he knew i may be coming back. i brought the page from a service manual about taper, and p2w and my notes. also with the girdle torqued town, the taper was still pretty much the same (differing from top to bottom +.0040ish

His explanation was that he does work with a lot of domestic high output motors, and a lot of these guys dont mind the extra room at the bottom. He tried to assure me ring travel wouldnt go that far down, but i argued that well its still exceeding anything recommended even using your guesstimate of my crank stroke and where my rings would be. after some nudging he finally gave in "your not happy, so im not happy, how can i make it right"

he explained to me his issue he saw with the honing skipping at the bottom, but didnt think it would be a big deal.

ill call tomorrow or monday, he said he may find me another short block, or replace the sleeves.

 

Now THAT is how you approach a business with concerns and want results without a fight.

Good job.

 

That sounds like an extremely reasonable proposal provided he follows through. I still think he's a hack for sending off a block that he knew damn well was not up to scratch, but at least he is willing to make it right by you. Can't ask for much more than that when you're in a situation like this.

In his defense, if he doesn't specialize in import engines, that kind of work would probably pass no problem. Our engines need much tighter tolerances to work properly. Back when Honda was pumping them out in the 90's they were the only company getting production engines tolerances down to the tenth. That is what made them so reliable and got the attention of companies like AEM. As far as cylinder walls are concerned, our engines use much thinner ring packs than american v8's and the rings are much more fragile. They need a minumum of a 400 grit hone and (in my opinion) a maximum of 0.0012" to 0.0013" of taper to seat properly. Where as with a v8, you can be all over the map and its still going to run half way decent.