EFstyle

Alright, so my buddy bought a rebuilt d16y8 off ebay for his 97 ex coupe. him an another friend put it in and got it all running. then i guess one of the coolant lines blew off and the motor overheated. how bad? im not sure thats all i know. now since then it has been making loud slaping noises. so I helped him pull off the head to find out that the pistons on cylinders 3 and 4 where hitting the head (4 much worse then 3)

what do you guys think? warped head? i didnt think a warped head could actually create piston/head contact. thanks for any input

EFstyle

up

98civdx

timing issue?

Rotten Egg

not tighten down right...possibly over torqued on the ones side...or like above..timing issue but i would think timing would be all 4

EFstyle

there was no valve contact, just the pistons hitting the head. so timing is out of the equation... is a warped head very easily seen? I tried taking a straight edge to both the head and the block and then seem pretty straight from what i could see.

98civdx

opps sorry read it wrong,
yea if the head is warped bad you can see it
lay it flat and look at at it from 1 end
forget that get a level lay it accros.
that will tell you.

EFstyle

Yeah I tried laying a staight edge on it from 4 angles, and disnt see anything out of the ordinary. It looked straight.

T3KNiQe

Can you do a compression test and post results?

Also have you looked at the headgasket?

EDIT: Maybe pistons 3 & 4 are different models kinda like aftermarket high compression pistons,,,is that even possible and the car still run???

REDesignIT

decked head and the wrong gasket thickness.

On the rebuild or previous rebuild the head was decked to make it true, during your rebuild you used the stock thickness gasket thus bang, smells like running rich, low fuel mileage and lots of carbon being dumped into the manifold and lots and lots of heat, boiling the cooling system due to excessive cylinder heat.

98civdx

he said noithing about it runing rich, low fuel mix!

take the head into a shop and have them look at it.
i might look straight but it might not be,
has the rotating assembly been change at all aftermarket?

REDesignIT

yupe I know he did not say anything, but they might not have had anytime really running it ? or did not look for the signs ? Home rebuild maybe did not measure the stroke height, rotated the pistons manually and measured the tdc to deck gap ?

Don't know how the rebuild was conducted so too hard to say, but if they pulled the head he could tell us by visual inspection of the ports what it looks like, lots of charring etc or relatively clean, also no word how long between when the rebuilt motor was dropped in to when it blew the head gasket, a week a month 3 months, 5,000 miles ? a day ?

Oh jeez I just read through the OP again, they purchased a "rebuilt" motor complete and just droppped it in the car. Drove on it, blew a cooling hose, drove the car until it overheated. (I assume fixed the hose and re-filled the coolant, did they burp it ? who knows) drove some more then heard slapping sound. Took head off, saw piston to head contact.

Damn man could be all kinds of things wrong with that motor depending on how long the motor was running while overheated.

Cylinder wall scaring, rod bearing spun, causing rod knock, running the motor overheated could have warped the head on the block thus causing the pistons to hit the head after they "corrected" the blown hose issue.

I would be amazed if that cylinder was even still firing and the "knocking" noise was really a dead cylinder.

yoffer

He just said that there was piston to head contact. That would basically eleminate the possibilty of almost everything you've stated. And in the entire paragraph that you have written, you've not given any helpful information. A spun bearing has completely different symptoms than what OP has stated. And cylinder wall scaring is caused by lack of oil and improper ring gap size or overheating. But cylinder wall scaring is not going to cause piston to wall contact. My guess is that the original builder used incorrect pistons.

REDesignIT

I think you are missing my point, "in addition to" the piston contact on the head, there could be more problems.

Not that they caused the piston to hit the head.

Ozcams Razor (spl?) the highest probability and most likely cause is usually the correct one.

Thus too close of tolerance in the deck height with incorrect gasket aided by an overheated and warped head more then likely caused the piston strike on the head. Resulting in the blown head gasket and............ any number of other issues in the bottom end due to driving on the overheated motor.

And regarding helpful information I think it is quite clear there is something "dimensionally" amiss with that motor. Since the head is off, like I suggested they can turn the motor and measure the gap at TDC for each cylinder and check the rebuild spec for the motor through a competent engine re-builder.

Either way that motor needs to be rebuilt from the bottom up if you ask me and checked, maybe the wrist pin to rod hole is elongated and allowing one piston to float at TDC thus striking the head before starting on the down stroke. Who knows, have to tear it completely down to find out.

Do all the piston tops look the same? maybe after they pull them out it will be apparent that one or two of them are the wrong piston. If they were all wrong I doubt the motor would have even turned over. The chance seriously that one out of 4 pistons is the wrong part is kind of low if you ask me.

The chance that someone slapped the motor back together and did not bother or even were concerned to mic the piston gap or just eyeballed it, I think is more likely.

Romo Pyro

Greatest post ever. IMO.

Romo Pyro

To the op, sorry to hear. best bet, buy a virgin motor. save up for a valvetrain, then cams. take it to a reputable shop, port and polish the head, and have them install everything while theyre at it for no extra charge, then some nice I/H/E, and a tune. keep it simple. take it slow. research EVERYthing you do beforehand, and I mean extensively. you should be able to teach a class on the mod before you add it to your car. and do everything yourself, or know whats been done EXACTLY. that way, this **** doesnt happen, and when it does (cause it will, no matter), you know why, and how to fix it. Goodluck.

REDesignIT

sound advice there Pyro and very true.

Romo Pyro

Thanx!

yoffer

Or save the money and buy a b16. Spending all that money for a d-series to make power is a waste imo.

Romo Pyro

true, but in all honesty, ive found a single cam to be quite more reliable, cheaper, and easier to work with than a DOHC. i mean in the long run, so if hes just looking for a lil bit of fun out of his daily. then this would be fine.

yoffer

He can get a complete y8 swap for way cheap. I just wouldnt spend any money into as far as making more power goes. Because if hes concerned about making power, then d-series is not the way to go. Unless you turbo it.

Romo Pyro

All motor Single Cam

http://www.youtube.com/watch?v=r52WRred23A


And thats what I could find in 30 seconds of searching. Dont doubt my friend.

i drive a honda

i have seen this only once.
rod strech, checkk for it, as name implies the rod is stretchered out of spec.

or maybe the guy whp rebuilt the motor, didnt check for that, milled the head, and block. or might have grabbed an off the shelf piston set and might have grabbed 2 different sized rods, weirder **** has happened

Swansen

Thats my guess to. it just seems like the stoke is too long, maybe he put in wrong crankshaft......

marcs1337

dang that sucks...id email the ebay guy....

yoffer

Well for one, that car is light as fuh. Second, with a good b16 swap, you can run high/mid 14's all day stock for way cheaper the price that it would be to build up a single cam. And obvisously this is a track built car.