D15B7 decisions

D15, D16, D17 and Mini-Me swaps
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D15B7 decisions

By ManiacMagoo
- Sun Jun 21, 2015 8:13 pm #354291 My D15B7 has roughly 40k miles on it since rebuild by previous owner. (others words no damn clue what condition it is in) I'm consuming oil and have a smoke trail part time when taking off or climbing hills with the car loaded. Given the compression is all around 200psi I'm leaning toward oil control rings except for the puddle of oil in the intake manifold. It has a new pcv valve from Orielly's but hell it could just suck. When it does smoke there is a where fluttery noise from the upper end of the motor almost like the pcv valve is getting fluttered like mad. The motor still holds 40-50 mpg on every tank which tells me it can't be to unhappy.

So now I'm trying to decide if I want to rebuild the D15B7 or get a D16Z6 to rebuild and swap in. This car is a commuter and a 95 coupe dx. We haul our family of 5 in it often because the gas mileage is awesome lol. I really would like to keep it above 40mpg if possible but don't know enough about the D16Z6 to know if it can. The extra power would be nice when we go camping up the passes but I really want to keep the mpg and durability. If I wanted to get nothing but power my K24 would be in it already. So any input would be awesome.
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By teal_dx
- Mon Jun 22, 2015 1:42 pm #354297 The d16z6 would give you the slight extra power you need @ high RPM (like for passing), and still give you decent mileage, almost as good as the d15b7. I doubt you'll see above 40 with the z6 swap. The d16z6 civic ex coupe got mid-high 30's. However, you'll have the longer-geared d15b7 transmission instead of the short-geared d16z6 transmission, so that will help your highway mpg :thumb:
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By iLLson
- Mon Jun 22, 2015 3:15 pm #354306 i would start cheap and replace the pcv valve.

oil in the manifold indicates that the pcv valve is working incorrectly.


a easy way to check will be to remove the vacuum line from the intake/valve cover and see if its seeing vacuum.

if its blowing out of the valve cover port, then the pcv is dead.

if the pcv valve is bad, then the oil is shooting in your intake and going to the manifold. it will then burn the oil.

a $15 oem pcv valve is way cheaper than a swap or a rebuild so start with that then let us know if it fixes your problem





ps: any d motor with 5 people in the car is going to suck mpg wise.
get the car running right, proper air in the tires, and a little bit of aero upgrades will help you.

good luck on 40+ mpg with the car filled.
look into ecomoding

By mid_egf22
- Wed Aug 05, 2015 5:52 am #355188 have you removed the spark plugs just to see if there is major oil build up or signs of oil inside the combustion chamber?

also to do a pcv function test make sure engine is at operating temperatures. fan kicks or run car on idle for about eh 10 mins should do the job to take it into close loop. To do the test pinch the pcv hose that goes to the manifold, NOT intake tube, with locking pliers. rpms should drop maybe -+50. You can tell if rpm drops simply by pinching and releasing pliers a few times just for assurance. if rpm drops it means pcv is operating efficiently. while your at it you minus well test your whole engine for any pcv leaks. do so by removing pliers of course. pinch vapor hose going to intake tube. take a vacuum gauge or boost gauge with vac readings and plug the vac hose into the dip stick. Of course you need to make an adapter for it somehow to fit a bigger hose to fit the dipstick tube. you should see vacuum. if NO vacuum u have a leak. most likely common honda oil pan leaks or dist o ring leaks. kind of a bit of work to it but hey i like painting a whole picture then go from there.
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