asdfqwer426

Hey, so a few weeks ago my timing belt broke. car ran fantastic before, no issues at all. after digging into it, i found that one of the two bolts holding the motor mount on under the timing cover had snapped off and wedged against the belt until it wore through and broke.

I replaced the belt in hopes that i got lucky and didn't bend valves, but after reassembly it didn't want to fire. it ALMOST did, but i could tell there was a serious lack of compression, it sounded like it was spinning too easily.

today i removed the head of my engine to assess the damage.

now, i have some questions, hopefully for someone who has had a timing belt break on them before. I've dealt with bent valves before on a dirt bike, and it was very obvious they were bent. looking at mine though, it's hard to tell.

I'm wondering if these valves when bent by this happening are very subtly bent, and hard to see by just eyeballing it?

the pistons looked good, i didnt even see any really obvious marks from hitting the valves, which confused me.

I read when searching the forum that some even had cracked valve guides, is this common enough i should be worried? i'm planning to do all the work myself and would like to not spend the money paying someone to inspect it.

another question, does anyone know if only the large valves get bent? (I forget for sure, those are intake right?) since the smaller valves have more clearance and might not hit the piston?

long term, my plan is to buy a top end gasket kit and probably a complete valve kit and just replace them all.

to any one else who has had this happen or knows a bit more about it, is there anything else i should look for or keep in mind?

thanks. sorry for such a long post with lots of different info and questions all in one blob. hope it makes sense.

B_Swapped93

When this happened with my y7 the valves were burnt(timing belt didn't sanp it just needed to be replaced) i went and replaced all 16 valves just for good measure. yes "big ones" are the intake valves. my advice just replace them it's like 80.00 for all 16 on ebay.

Marvin1985

iTrader: (5)

Maybe you would find it a good time to do a mini me head swap?

DanCan'tSwim

the belt on my d16z6 snapped on me about 8 months ago.

if you want to check if the motor is good without replacing anything, check timing!
with the belt on, make sure the cam is at TDC and the crank pulley mark is lined up with the belt cover mark. if she sounds like she's going to start but sounds too weak. recheck timing. the belt might be on too loose.

you said it happened a few weeks ago..could your battery be weak aswell? may need a recharge.

asdfqwer426

b_swapped - thanks for the help again, I too was thinking if anything i would just replace them all since, like you said, about $80 and you can buy a full set.

Marvin - I'm not too familiar with modern honda autos, my main expertise is 70's honda motorcycles, what is a mini me swap? a quick google search makes me think its some sort of vtec swap?

dancantswim - my heads already off, but I was pretty careful to check and double check the belt timing when i tried just replacing it. it was spot on and nice and tight. Also, the battery was pretty weak, but I was actually using a heavy duty battery charger on a 60amp setting, i'm fairly certain it had plenty of charge as it was cranking very easily. also, i very recently had my alternator rebuilt, so i'm confident that if it was going to fire, it would have. But, thanks for the battery idea.

As i'm familiar, but new, to these engines I wanted to just run what i was doing by some people who were more familiar to see if i was doing the right thing and it sounds like i am.

apexi_rsx

should have did a compression test with the head on .... toooooo late now. d16's are interference motors 9 times outta ten u bent valves

asdfqwer426

well, got a closer look at the head today, pulled the cam/rockers and got the valves out. all of my exhaust valves are bent, some more than others. all of my intake look good, but i'll be replacing them anyway.

hopefully next week when i get the parts in I can get it back together and call it done.

thanks everyone for their help.

eghatch9295

iTrader: (1)

he is talking about swapping a vtec head on your non vtec block. from the sounds of it, it is a daily for you.. i would just rebuild your current head and call it a day

xile6

Pix?
And sucks about the bent valves.
My old del sol with a d15b7 had the cam tooth break. When i replaced the cam gear she was all fine.
But i know these d16 have a higher comp.
Good luck with the rebuild.

crazyhouse2011

How did it just damage the exhaust valves and not any of the intake valves? Seems quite fishy. Is it a single cam or a DOHC?

asdfqwer426

pix of the valves? i could get those.

I think its the construction of the head that made it only bend the exhaust valves. the intake are closer to the center of the piston, which is lower than the edge. the exhaust however are much closer to the rim of the piston, so even though they're smaller, they have less clearance to the piston than the intake. Is what I think.

crazyhouse2011

Whatever you just said made no sense at all.

eghatch9295

iTrader: (1)

makes perfect sense.

xile6

Intake valves do have valve relief on the piston while the exhaust doesn't so it is possible.

asdfqwer426

Another thought on the exhaust being bent and not the intake is that given a rotation of the cam, the exhaust would open first. the belt would have to break in a small spot to bend an intake before an exhaust.

anyway, I have some questions and some pictures.

first, in my gasket kit i have all these little rubber pieces and rings and i dont know where they go. I know the top pieces are exhaust gaskets and valve cover things, its all the rubber o ring parts.


second, I know on my 90 accord there was a filling/bleeding procedure to the coolant system, is there one like that on this engine?

third, just is there anything i should know about restarting my car after having taken the head off?

and here are some pictures.
all my old valves laid out. half the springs are already re-installed.


a close look at the exhaust valves shows where the carbon broke off when the metal bent.


and it can be seen all the way down the line.


heres one of the more bent valves between 2 of the still straight intake valves.


half of my valves lapped and in place.


and finally, what the heck is up with the location of the PCV. what a pain. had to take the little box off to fish out half of the old one.

sleepyaccord96

he clearly stated in the title of the thread it is a d16y7, if you don't know what that is why would you chime in and even reply in this thread.

OP you may want send the head away to the machine shop and have it checked just to be sure everything is ok...as in warpage or anything of that sort. I know you didn't say it blew the head gasket but it is still not a bad idea to have it inspected before re install

Also, the idea of doing the vtec head is a good idea to go ahead and do now while the ol y7 head is off.

asdfqwer426

I like the idea of the vtec swap, but this is my daily driver and my job is delivering pizza, so getting it running ASAP is my priority. perhaps this summer though, I can put a d16y8 head on.

anyway, busy day today. got everything back together. i was a bit nervous cranking it over because it didn't want to start right away, but i knew it would take a bit for fuel and coolant to work its way in. it eventually started up and its running just as strong as before. already put 100 miles on it today.

there is only one issue. at first when i started to drive it, when giving it plenty of gas it would sometimes shudder a bit. I was hoping it was either the ECU relearning what it's doing or just a bit of air left in the fuel lines. after the first 15 miles or so it stopped doing it. anyone have any idea what it might have been?

B_Swapped93

mine did some sputtering/choking at first it's just normal if you spilt some oil/coolant in the cyl(from my experience). or could have been some air in the coolant sys. nothing to worry about

jdmpeteek9

Yea bro my wife hade a d17 out of a em2 and the timing belt riped on the freeway at about 80mph. She bent 14 out of 16 valves. We bought all new oem valves and i took the head to the shop to get it cleaned and resurfaced. Its not a big deal but you should also replace your water pump while your at it. And once u put everything back together make sure u do a valve adjustment and check timing.

crazyhouse2011