It's my own damn fault. Rather than fix the flat in my truck I hopped in my Mother's GS-R which was overdue for a timing belt. Snap. Now I'd love you guys' advice on possible next steps.

I've got just about everything ready for the timing belt replacement. I caught this break pretty much immedately after it happened. Which obviously has me wondering if there's a chance the valves are okay. So then, the questions...

1. I saw a lot of people suggest a compression test to see if the valves are pooched. Let's assume they're not. Wouldn't turning the motor over for a comp. check cause additional damage?

2. Would checking valve clearance possibly tell the story of bent valves? If so, what would the symptoms be?

3. Let's assume some valves got tweaked. How badly does a B18C run with some bent valves? If the answer is "it's a little down on power" then I'm inclined to leave it alone, as it's just a commuter car. If the answer is "it runs like complete chit," that's a different story.

Just trying to figure out if I can get away with just putting the belt on and driving it, and not do the significant work of pulling the head off. TIA...

 

slap the new belt on & run ur usual basic test: compression & leakdown OR pull the head off and check everything.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 3rdGteg &raquo;</TD></TR><TR><TD CLASS="quote">slap the new belt on & run ur usual basic test: compression & leakdown OR pull the head off and check everything.</TD></TR></TABLE>
best thing to do

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 3rdGteg» &raquo;</TD></TR><TR><TD CLASS="quote">
slap the new belt on & run ur usual basic test: compression & leakdown OR pull the head off and check everything.</TD></TR></TABLE>
if the car was in gear while running, i would pull the head, cuz there is big chance valves are bent, but if the car was idling or in neutral and it just turned off i guess you could do what he said, just put the timming belt and run compression and leakdown. good luck man, hope is just the timming belt.

 

I skipped time (not as bad as breaking the belt entirely I realize) once and didn't really hurt anything other than the car ran like shiat. A compression check is your friend. I was seeing 200 psi per cylinder before I skipped time and I'm seeing 240 across them now. Planning on replacing the belt and tensioner this week... Bottom line, it's the luck of the draw. Our engines are interference, so if you were driving it as was said earlier, there's a good chance that you got some of the valves..

 

pull the head and investigate.

 

mine broke going about 30mph in 4th gear (last time i believe the dealer when they say they've already changed something). checked compression, checked for bent valves, slapped a new belt on and she fired right up. runs as strong as ever. not something i'd gamble on again though...

 

Thanks to all. I'll put a new belt on it, button the rest of the thing up, and do a compression check. If the numbers look good I'll consider myself one of the lucky ones. If they don't...time to redo the whole job.

Note to anyone reading this: Honda is NOT KIDDING when they say replace that timing belt. Learn from my mistakes.

--Karl, who might be the owner of a bone stock Integra GS-R soon...

 

karl dont only do a compression test unless you know exactly what the #'s should be (or close enough). do a leak down test also to make sure you are good to go.

oh and the answer to some of your questions. if you put the belt on and try cranking the motor and it doesnt crank and you hear air going back into the intake, then you got bent valves. i just bent 8 intake valves last week. they were slightly bent and i had to look really close when the valves were in the head to even see how they were not flush with the seats.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by baonest &raquo;</TD></TR><TR><TD CLASS="quote">karl dont only do a compression test unless you know exactly what the #'s should be (or close enough). do a leak down test also to make sure you are good to go.</TD></TR></TABLE>

I was thinking if they're in the mid-200 range...like the motor in the race car...good enough.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by baonest &raquo;</TD></TR><TR><TD CLASS="quote">oh and the answer to some of your questions. if you put the belt on and try cranking the motor and it doesnt crank and you hear air going back into the intake, then you got bent valves. i just bent 8 intake valves last week. they were slightly bent and i had to look really close when the valves were in the head to even see how they were not flush with the seats. </TD></TR></TABLE>

So will a motor with bent valves not even run? Down on compression I'm okay with. Stumbling motor that will barely run I'm not okay with.

So I ask again...is there a way to test for bent valves on a motor that's got a bad timing belt, that will tell the owner "Yes, pull the head" or "No, you're probably okay
" ? Without doing additional damage to the motor?

Dang. Should've fixed that flat...with a 103 deg. F temperature I guess I wasn't thinking straight...

 

you have IM

 

I'm going through the same crap right now (see my threads in this forum). My timing belt snapped while I was trying to start my car, so it wasn't moving or in gear. Hopefully I'll be okay. I plan on putting a new t-belt on today...in the rain...so I'll let you know how it goes.

 

im not 100% sure if a motor with bent valves will run, but i really dont think it will because air would be escaping. now i dont know about exhause valves, but i had intake valves bent. it just was turning and turning and farting back through the intake.

but again, if you did have bent valves the compression most likely would be 0.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by krshultz &raquo;</TD></TR><TR><TD CLASS="quote">... So I ask again...is there a way to test for bent valves on a motor that's got a bad timing belt, that will tell the owner "Yes, pull the head" or "No, you're probably okay" ? Without doing additional damage to the motor?</TD></TR></TABLE>
The belt's broke, right? Here's what I'd do first, 'cause its real easy.

Position the crank to 90 degrees away from TDC. Whichever direction is closest, just don't move it through TDC or BDC. That way all 4 pistons are at mid-stroke, none are at the top. Now you can turn the cams all you want without fear of hitting the pistons.

Turning each camshaft by itself, measure the valve clearance just like you were adjusting valve lash. Any valves that are bent, the clearance will be way to big, since the valve isn't closing all the way.

If you lucked out, then position the cams properly (arrows up). Now all the valves are closed and you can rotate the crank to TDC & put on the new belt.

 

Karl the best thing to do is suck it up and replace the timng belt before you go pulling the head, there is a small chance, a very small one, that nothing is damaged. once the belt is back on, do a compression test and pray.

we should add this to the "karl is cursed and has cursed everything i own" thread in the RR/autox forum

if you need to unload a GSR motor with bent valves let me know hehe

 

it wouldnt make any power if the valves were bent, your pressure in the cylinder along w/ fuel ext would excape through the bend valves. Same happens when you burn an exhaust valve you lose pretty much all compression. It be like pulling the spark plug wire out and running your car, it would idle like crap!

 

Now this is a kickass piece of information - exactly what I needed. Many thanks!

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote">
The belt's broke, right? Here's what I'd do first, 'cause its real easy.

Position the crank to 90 degrees away from TDC. Whichever direction is closest, just don't move it through TDC or BDC. That way all 4 pistons are at mid-stroke, none are at the top. Now you can turn the cams all you want without fear of hitting the pistons.

Turning each camshaft by itself, measure the valve clearance just like you were adjusting valve lash. Any valves that are bent, the clearance will be way to big, since the valve isn't closing all the way.

If you lucked out, then position the cams properly (arrows up). Now all the valves are closed and you can rotate the crank to TDC & put on the new belt.
</TD></TR></TABLE>

Edit: spelling