So I'm looking to buy a "new" motor for my car. I found a D16Z6 with ~100k miles on it. I went to check it out today and it's real clean with everything intact and no leaks. The seller has a trans he's selling with it and he said he could crank it over to prove it's not seized and we also did a compression test on it. We cranked the motor over with a battery jumper that was almost fully charged and the motor was obviously cold when we did this so I'm assuming the numbers won't be completely accurate.

Here is what we got:

Cylinder 1: 155psi
Cylinder 2: 155psi
Cylinder 3: 145psi
Cylinder 4: 155psi

Standard is 184psi with a minimum of 135psi and a maximum variation of 28psi between cylinders. So, clearly even under cold a cold crank and a slightly weak battery, it produced some decent numbers and with no serious variations.

What I'm wondering is, do you guys think the numbers would be higher and more accurate if/when the motor is warm and with a strong battery? What can you guys make from these readings, espcially the lower number cylinder 3 produced?

The guy is selling this complete motor, trans, wire harness, axles, ECU, etc... for $500 so I'd love to pick it up. I just want to make sure it's a healthy motor so I can do a direct swap and be worry free.

I'm going to do a warm and cold compression test on my current motor which has 211k miles on it and see what it produces. I'll also do one on my '99 Civic EX that has 135k miles on it just for further comparison.

Any input is greatly appreciated.

Thanks!

 

I just did a compression test on my car with a warm engine. I did it twice to be sure.

Cylinder 1: 195 & 190
Cylinder 2: 180 & 185
Cylinder 3: 195 & 200
Cylinder 4: 195 & 195

Seems to be a bit high which from what I understand, can be caused by carbon deposits. Which with a 211k mile motor, I'm not at all surprised.

I'll do a cold test later with this motor and do the same tests on my other Civic.

 

Based on your numbers, I'd keep the current engine. What's wrong with it?

My guess is that the engine you are considering buying is also fine, though a warm engine compression test would be nice to confirm. Does it come with any guarantee or warranty?

 

My current motor has 211k miles and the car it's in is my race car, so it gets beat on. I'm losing confidence in it lasting especially now that it's leaking a good amount of oil from what appears to be the head onto the trans(I know it's not the dizzy or vtec solenoid or anything like that). Plus I had the car on a dyno a month ago and it's not producing the power it should. To be competitive I'd like to get back the lost power with a newer motor.

I'm buying from an individual seller so no warranty or anything.. But I do know it cranks over and compression seems to be fine. I might try to go back and do a leak down test on it before I buy it.

 

If you're worried about compression, throw a can of Restore in with your next oil change, let it go for a couple hundred miles, then check compression again.

 

Went out and bought a leak down tester and got the ok from the seller to go up tomorrow to do the test. Wish me luck! If it does well with the leak down, I'll buy it..

 

Anyone know if the compression numbers are that same for a D16Y8 as to aD16Z6(184psi standard, 135psi min)? Doing a compression and leak down test on my daily driver for comparison and curiosity.

 

Alright so I've finally gotten everything taken care of after 3 trips up to York, PA to check out and test the motor and whatnot...

So here's the run down of what I've done this week regarding tests...

My '95 Civic EX race car with 211k all original miles:
Compression(hot engine average):
Cylinder 1: 193
Cylinder 2: 183
Cylinder 3: 198
Cylinder 4: 195

Compression(cold engine average):
Cylinder 1: 183
Cylinder 2: 190
Cylinder 3: 195
Cylinder 4: 188

Leak down test(hot engine):
Cylinder 1: 7%
Cylinder 2: 35%
Cylinder 3: 23%
Cylinder 4: 20%

Leak down test with a cold engine had very similar results, only a 1-2% difference on average compared to the warm engine test.

My '99 Civic EX daily driver with 135k all original miles:
Compression(hot engine):
Cylinder 1: 195
Cylinder 2: 200
Cylinder 3: 205
Cylinder 4: 205

Compression(cold engine):
Cylinder 1: 200
Cylinder 2: 200
Cylinder 3: 210
Cylinder 4: 210

Haven't done a leak down test on it yet..

The motor I'm looking to purchase:
Compression(cold engine since it's not in a car):
Cylinder 1: 155
Cylinder 2: 145
Cylinder 3: 155
Cylinder 4: 155

(he mentioned he has seen 165 across the board before)

Leak down test(again, cold motor):
All cylinders read right around 7-9% on average.


So what do you guys think? Based on the leak down test, seems like my current motor in my '95 has had it, mainly with cylinder 2 reading 35%. I'm not at all surprised though. For the miles and beating its been though, I'm happy with it. More importantly though, what can you make of this other motor I'm looking to buy? The compression numbers seem to be ok, very consistant. I am interested to see what readings I'd get with a warm engine. The leak down test seems quite good aswell, all cylinders were under 10% with no noticable issues. Good motor? I'm pretty set on getting it at this point. Once I have it, I'll replace the timing belt, water pump, and oil pump while the engines out..

 

Why are the cold compression numbers on the D16Z6 so much lower than those of your 95 race car engine? Are you unable to get a comparable crank speed from the uninstalled d16Z6?

 

I would imagine it'd have to be for a couple reasons. When we tested his motor, we used a battery jumper to crank which the jumper was almost fully charged, not quite fully charged. We also didn't crank as much, maybe like 5-6 cranks. Also his motor has around 100k miles. When I did my motor, I had a fully charged battery, cranked 7 times and my motor has 211k miles which I'm sure has carbon built up and from what I understand, the numbers could be higher because of that carbon. Crank speed from my motor seemed to be faster but I believe that's due to my battery being fully charged and ableto supply the needed power.