Hello everyone,

I am a very long time lurker, around 2 months ago I purchased my first EG.
Its a 92 CX with a D15B8, super slow lol but good on gas.

I noticed that it was nearly empty of oil last week, after about 2.5 months and no more than 1300 miles on that interval.
I also noticed during those couple of months driving that sometimes on 1st or second gear while accelerating I can see smoke from my rearview. The windows are really tinted and didn't notice unless I looked intently.

I took it to a friend of mine who fixes cars from his garage.
He had me put the car on neutral and accelerate, after a few seconds there was a lot of smoke out of the exhaust. He told me it needs a new engine block.

I trust him but I wanted to run it through you guys since google results kept bringing up similar threads. Should I do a leakdown test first?

What engine block do I look for? does it have to be from a 92 civic cx as well or is there other compatible parts/years?

Thank You guys for taking the time to read.

 

If the cylinders have good compression, then you may just need to replace the valve seals.

 

So you recommend a leakdown test first?
Also what if they don't have good compression?

I just want to fix the problem, my friend and I would be doing the work
using online tutorials/youtube. I like the car and don't want to be polluting more than I have to.

 

As RonJ mentioned, it is possible that you could have an issue with your valve stem seals, and/or valve guides, but more than likely you have an issue with blow-by via the piston rings. Common of high mileage engines. To confirm this, you can do a wet/dry compression test, or a leak-down test. As mentioned, if your compression numbers are on the high side and do not vary more than 10-15% from dry to wet compression, its likely your issue is with the valve stem seals or valve guides. In which case, a cylinder head rebuild will resolve your issues.

However, if your compression numbers are low, and you have significant increase in compression from dry to wet comp tests, you might consider a rebuild instead of trying to find another engine. Chances are, if you source out a used D15B8, you'll end up with something with equally as many miles and could have similar issues as yours does currently. You could also swap in a low-mileage JDM D15B non-VTEC longblock (reuse your intake/exhaust manifolds). The engine that came stock in the CX was the D15B8 - 1.5L SOHC 8V non-VTEC.

If you're interested in a rebuild, or a JDM low-mileage engine, PM me - we can definitely provide you with either.

 

It could also be stuck oil control control rings.

If you live in the states, walmart has Marvel Mystery Oil (MMO) as do many of the autoparts stores. It's been being used for over 50 years without issue.

The process to rule out oil control rings is to poor a little bit (1-2 oz) in each cylinder and let sit overnight (pull plugs, poor in, reinstall plugs, don't drive until the next day). Do this for 2 or 3 days and it can loosen the control rings. It's what I'm going to do this weekend to rule out that possibility.

If it seems to help then you may want to add 16 oz of MMO every oil change for awhile. It's a gentle solvent that will clean the engine out as you drive and will undo the build up of sludge that tends to happen with lots of short trips. It could be the previous owner never really did any long trips to fully warm up the engine, oil and burn off carbon.

Then there is another additive I know that can help reduce oil consumption, improve mpg and add a little extra time to a motor that is much cheaper than doing a rebuild, swap or even major seal replacement in most cases. It won't help with leaking seals though.

Before worrying about that additive, you need to get the engine clean so all the rings are working properly before doing any restorative tricks.

This is true for the USA. In Canada the CX came stock with the D15B7 16V non vtec motor.

 

Thank You guys for being so helpful.
What should compression numbers generally be at?
My mechanic friend told me it would be pricier to rebuild, than to source a used engine block although the used engine could be risky. He says we can reuse the head?

 

It will be more expensive, yes. But do you really want to gamble with your money on a used block having the same issues as you're already experiencing?? Or having this issue again shortly down the road?? Do it right the first time, otherwise you'll end up spending 2-3X the amount of money as you would doing it right the first time around...


Here is a great how-to on testing compression on Honda 1.5/1.6 engines...
How to Test Engine Compression
(Honda 1.5L, 1.6L)

 

Thanks bro, so why is loosening the control rings good?
Can this test be done without affecting anything else if it isnt the oil control rings?
There seems to be many possibilities, so i am leaning to getting the leakdown test first. If i do it, is a compression test also needed?
It has 160,5xx Miles on it right now, what is best bang for the buck... rebuild, swap engine or swap engine block?

Just want to do things right the first time

 

How about we worry about diagnosing the actual problem before we worry about what needs to be replaced, OK?

OP, do a compression test, post the numbers. They should be above 160, and within 5 PSI of each other. Once you've done a dry test, do a wet compression test. It's the same as a normal compression test, but you put a teaspoon of oil in each cylinder before doing the test.

Post the compression numbers for both tests, and we can work from there. If your "buddy" immediately said you need a new block, he is either lazy and doesn't want to do the work, or he has no clue what he's talking about and should go back to the oil pit.

 

I agree I just want to do it right, I've been reading non-stop trying to learn as much as I can. Is there a way to test the block before buying I was using car-part to search parts from local wreckers/junkyards

 

Diagnose the problem before you buy anything. Don't just haphazardly throw parts at the car. Don't even start thinking or worrying about where to get replacement parts, or how to make sure they're usable. Diagnose.

 

LOL thanks man, I will definitely post up results here.
I was told leakdown test is better than compression?
Do you recommend both? Thanks for clarifying the wet/dry procedure

 

A leakdown test is better, but it requires tools that the average person doesn't have access to, specifically a pressure gauge set and air compressor. Using a leakdown test diagnostically also requires a bit of knowledge that the average DIY'er doesn't have. Dry and wet compression tests, when done together, can be nearly as diagnostically useful, especially when it comes to oil issues, and the only tools required can be easily borrowed or rented from your local major parts store, or bought for cheap. It's extremely easy to interpret, as well, because as long as you do the test correctly, you have solid numbers to give us.

 

Not really - unless its a complete engine where you can do a leak-down test, there isn't much you can do to test a shortblock. And as I mentioned before, everything you're going to find will be 20+ years old, and in the junkyard... If you're trying to do this a cheap as possible, without gambling your money away, go with a low-mileage JDM D15B non-VTEC engine. Don't worry about trying to reuse your head, just install the complete longblock w/ your intake/exhaust manifolds w/ new timing belt & water pump (recommend also replacing the front/rear main seals, valve cover gasket, and oil pan gasket since its easy and accessible when doing the replacement).

 

Uh, you do realize the whole "35k-45k mile JDM motor" thing is bullshit, right? Well, if you didn't, now you do.

 

Not sure where you get your information bud, but you are absolutely incorrect. Our engines/swaps are hand picked, inspected, and tested. All of which are verified to be under 60k miles before even beginning the testing/inspection procedures. At which time, if they pass our tests - they are loaded into a shipping container and imported state-side.

I cannot speak for other distributors of JDM engines, but ours are DEFINITELY under 60k miles, and we guarantee them as such.

 

Oh really? And you have proof of this how, exactly? Do I need to tell you every way in which that is an industry lie, perpetuated by the people who ignorantly buy them with no clue about where they actually came from? Testing them and verifying them is one thing, claiming exact mileage is completely different, and it's easy enough to "guarantee" something that can't be proven false. I guarantee you there's a God - if you prove me wrong beyond a doubt, I'll gladly refund your eternal soul. The whole concept that motors have to be replaced in Japan after so many thousands of miles is a complete and total lie. Considering you're in the industry, you need to educate yourself. The law that people (incorrectly) quote for the 62,000 mile myth is called Shaken. Go ahead, do some reading.

 

If the compression test reveals low compression in one or more cylinders, then do a leak down test to determine where compression is lost.

 

As i mentioned, we have a representative from our company that is overseas selecting which engines/swaps we purchase. Most often, the engines/swaps are still installed in the vehicles at the wrecking yards prior to dismantling/importing. This is how we verify mileage; there is no bullshit about it. Again, I cannot speak for other distributors, but this is how we do it, and this is how we can guarantee mileage - without a doub.

My apologies to the OP for his thread getting sent off-track here.... let's get it back on topic. Thanks.

 

Not really a test, just a cheap treatment.

Sludge and carbon buildup on the control rings can prevent them from moving freely and scraping oil off the cylinder walls which then gets burned during combustion. It can be a contributing factor to high oil consumption but usually isn't the only factor.

Personally I start with cheap things first (MMO 32oz is like 5 bucks) and then work my way up.

The compression tests that were mentioned are also a great provider of information. If numbers are low in any cylinder then you follow those tests with the leak down test to see where you are losing compression.

I've been told the stock PSI for the B7/B8 block when new is around 185 PSI, so 160 and above is pretty decent on high mileage engines.

You can also look at sourcing a rebuilt engine for probably close to what it would cost to rebuild your current motor. I know on craigslist there is a retired mechanic in my area that has my motor rebuilt for sale for $650. I know it will cost me at least that in parts to rebuild mine so it's a cost effective alternative. It's 160 bucks before tax just for the bearings alone, let alone rings, seals/gaskets and machine shop work.

 

I'm not sure who was blowing this smoke up your way but the way I have always heard it is that after X mileage insurance rates skyrocket. No law stating the motor has to be swapped. Just people don't want to pay extortion rate insurance for higher mileage cars so they typically swap them out every 3 years or so (the car, not the motor).

I've heard it's already exorbitantly expensive to own a car in Japan without having the raping insurance of higher mileage cars added in.

I personally like that his business goes out of their way to verify mileage before they import. That's quality that isn't found as often. Way to stand behind and support the hype everyone else rides the coattails on.

 

TomCat, it's not insurance laws, it's the Shaken law. Feel free to look it up and learn about it, and why claiming mileage is a lie.

Really, so you actually have someone on payroll that speaks fluent Japanese, and lives in Japan JUST to pick motors for you? No, you don't - that would eat away at any company's profits, and would be a shitty business decision. You have some random connections at junk yards that send you motors, and you take their word on the mileage on them. There is no hard proof, just a chain of "Reputable guy X said so". Don't get me wrong, it's great that the motors are tested before they're pulled, but does your company actually test them? What tests are done?

It's one thing to test all motors and guarantee them working, and that's great. It is, however, a bold-faced lie to guarantee mileage on an imported motor, as it is absolutely impossible to dispositively prove mileage. Like I said, I guarantee God exists. Prove me wrong. It's the same argument. Neither side can prove it one way or the other. so guaranteeing it is disingenuous at best, and a flat out lie at worst.

That being said, you can find bottom end rebuild kits for under $200, and gasket kits for about that as well. After honing, you could rebuild a D15 for $500 if you're comfortable with basic tools. Personally, if I was presented with a D15 that needed a full rebuild, I would rather put that money into rebuilding a better motor that would drop right in (a D16Z6 comes to mind), but that's just me. However, none of this matters until the motor is fully diagnosed!

 

Correct compression for D15B8 is 9.3:1... Compression per cylinder should be 184PSI if they are healthy. Minimum compression is 135PSI. The absolute highest variation between cylinders can be 28PSI.

 

For someone that acts like they know so much - you really don't know very much at all - you sure make some heavy claims/accusations. If you must know - one of our owners childhood friends moved back to Japan several years ago; of course he is not a full-time employee of our company - he works a full-time job just like anyone else. He is hired part-time as a consultant to do nothing more than source, inspect/test, and handle the shipping/exporting of our engines/swaps. As far as testing - in addition to visual inspections, the engines are leak-down tested and oil pressure tested prior to exporting, as well as once they are received here in the US. Not to mention, we warranty them anywhere from 3-6 months, depending on the engine. THAT'S how we can make the guarantee we do, and stand by it 100%. If you would like to discuss this further, you can PM me - I am done arguing with you about something that has absolutely NOTHING to do with the original posters thread...

And lets be honest here - your ideas of rebuilding are completely half-assed. Proper machine work and blueprinting should be done on ANY rebuild, which requires more than "basic tools", as you state. (polishing/mic'ing crankshaft, decking the block surface, honing cylinders, reconditioning the rod journals, etc.). Not to mention, if this engine has severe blow-by via the rings, the pistons are HIGHLY likely to be toast and not in re-useable condition - so to you, is a rod heater a "basic tool"?! Lol. Because these wrist pins are a press-fit, which will require a rod heater to remove old pistons, and hang new pistons on the rods... SMH...

 

Also, high carbon build up will cause the motor to have to high of compression normally. In which case it may just be better to remove the head and have it decarbonized...