00 GSR 60k mi. 2nd instead of fourth gear bent all 8 exhaust valves.
So I decided instead of replacing with OEM why not go with something better.
Fully PnP head, 3-way valve job etc.. I get a discount on skunk2 parts so I went with S2: stage2 cams, High comp. valves, racing valve springs, titanium retainers,
cam gears, IM. AEM: CAI, fuel rail, FPR, FP gauge, Greddy timing belt.
I already had unorthadox racing pulleys, test pipe, skunk2 catback, o2 sim chip, AEM big brake kit, DC sports4-1 header, short shifter.

I had a machine shop do all the head work and assemble the valve train $900, took it to the dealership to have the valves adjusted ($80 had no idea how easy it was to adjust them myself) Anyways I assembled the engine started it and it ran like a VW bug, pretty much just like it did before I fixed any of it. Oil started leaking from the head gasket (Fel-Pro gasket) At this point I was pretty pissed being that I was anticipating driving my car and really need my car. I dissasembled the engine to find that 4 of the exhaust valves are bent??? I thought mabye valves were not adjusted right or maybe the timing jumped???

I have not modified the bottom end at all did not even remove it from the car but the pistons and cylinders look fine there were just some minor scrape marks on the piston heads from the exhaust valves hitting just cleaned them off.

I order 4 new valves next day shipping almost cost more than the valves $118 total. Took it to the machine shop to have the valve replaced $40 buy a honda head gasket $78 re-asseble the engine thinking that if I adjust the valves and triple check the timing it will be running in a couple of hours. 4.5 hours later start it up to have it run like a tractor all over again. Turn it off check the timing its perfect? No head gasket leak this time. I advanced the exhaust timing by 2 deg. it idles a little smoother give it a little gas and let off it knocks hard and dies. Sounds like bent exhaust valves all over again????????? Start it up mess with the dist. timing helps a little, still sounds horrible. Took the valve cover off and turned the crank by hand and it sounds like compression leaks on all four cylinders???
Don't have a leak down kit or compression test. But I am pretty familiar with the sound of bent exhaust valves and am almost certain that is what it is. The car will not drive at all in fact it barely stays running when idling. It is not throwing any CE codes either.

How do you check valve clearance?
I have been told to clay the motor anyone know where to get the clay?

Has anyone had this problem or know why my pistons keep slamming into my valves?
Keep in mind the timing is perfect and valves are adjusted properly.
I did not ask the machine shop how much they milled off my head because I did not ask them to mill my head but have been told they always mill the head after they do work

I have put a couple of grand in this now and alot of time just to end up with the same problem I started with. Any advice would be much appreciated.

 

How sure are you that you are kissing your pistons? Unless your cam timing is way off I don't think thats your problem.

 

I am going through the same process right now, except I have another head on its way now. I just figured it was faulty work byt the machine shop, but I am not sure what will happen this time.

Also, I wondered if I could re-use my headgasket which was only used for about 30 minutes max before the head was taken off again.

 

I would not reuse the head gasket it would probably work but its not worth the time to have do pull the head all over again just to replace the head gasket you would kick yourself in the *** for that one. What kind of mods do you have?
What brand of gasket are you using?

 

Its an oem head gasket.

Car is stock except for AEM intake.

Headwork was all redone with stock gsr parts

 

When you say you are going through the same thing you mean you bent exhaust valve with no explanation? Explain please

 

I did the 3rd to second 2nd shift accedentally, and bent all 8 exhaust valves. I had stock valves, valve seals, valve guides, put in and seated by a certified honda tech. I put the head on the car after I got it back and have no compression in cylinder 2 and the car runs rough because of this. I have no clue what the problem is so I just purchased another head off of ebay with skunk2 valves and valve springs in it. I am planning on putting this head on my car and having the other one checked out and eventually sold after it is fixed.

 

Did you get the old valves back from the machine shop? If not, how do you know if your valves were actually changed?

Which timing mark did you use for TDC, white or red? White is right.

 

Have you ever seen valves out of a head with 60k on it vs. brand new valves??
Pretty easy to tell that the valves have been changed
Not to mention I replaced the OEM valves with skunk2 high compression valves that have a big S2 stamped right on the bottom of each valve
If you had read my original post you would have seen that I used S2 not OEM

As far as the timing mark is concerned when replacing the belt on a 00GSR
with the timing belt cover off and crank pulley off there is no white or red mark
There is an arrow stamped on the block and a line on the timing belt drive pulley

 

Man something is so wrong.

First, I wouldn't be pulling heads just by the sound. You have to do a leakdown test first.

Second, you problem sounds like it could be bad valve lash. Theoretically, a bent valve shouldn't sound like anything unique. The only thing you should be able to tell is that the cylinder isn't firing. Unless, you are hearing piston to valve contact, which will destroy the motor within a few seconds.

Third, when you assembled the motor, did you turn it by hand a couple of times to see that there was no contact.

 

I just found out that the machine shop milled 4 1000ths off of my head.
A stock p72 head has 8 1000ths clearance.
The S2 stage2 cams are far more agressive than the OEM with only 4 1000ths of clearance I believe this is my problem.
I have yet to pull the head (for the fourth time) to inspect the valves and have not done a leakdown test.
Valve lash: I adjusted the valves and double checked them all they are gooood.

Yes I turned it 3 or 4 times to seat the belt and re-checked the timing afterwards.

 

Your head being surfaced/milled down .004 will not cause your valves to bend. You have some other issue I can guarantee that.

 

Buy a compression tester for about $50. That is far cheaper than pulling the head again, especially if you don't need to. Don't worry about the untimate compression too much, as that can vary depending on the gauge. Just make sure that the compression is consistent in all four cylinders.

Are you positive that you timing belt isn't off a tooth? What about the cam gear settings?

 

check your valve stem seals...center dowel pin of the head..
plus, honda/acura dealerships don't know jack. take your motor somewhere else to get valve adjustments. it takes time to do a good job on valves.

 

Bought a compression test kit all within 10% of each other
#1 205psi #2 211 #3 210 #4 210
Compression is good but that doesn't mean that my valves are not bent
I need to find a leakdown tester to check my valves.


Modified by vman at 4:16 PM 7/14/2004


Modified by vman at 11:46 PM 7/15/2004

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vman &raquo;</TD></TR><TR><TD CLASS="quote">Bought a compression test kit all within 10% of each other
#1 205psi #2 211 #3 210 #4 210
Compression is good but that doesn't mean that my valves are not bent
I need to find a leakdown tester to check my valves.
Correct me if I am wrong

Modified by vman at 4:16 PM 7/14/2004</TD></TR></TABLE>


you can't have bent valves and still have compression. There is no such thing. Soulnds like you are haveing other problems

 

You can still have compression with bent valves the only real way to find out if you have bent valves is to do a leakdown test.

 

well, my problem was that cylinder number #2's exhaust valves were not seated right by the machine shop.

I bought another head with skunk components (valves, valve springs) and will be installing this sometime this week.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Stewie &raquo;</TD></TR><TR><TD CLASS="quote">
you can't have bent valves and still have compression. There is no such thing. Soulnds like you are haveing other problems</TD></TR></TABLE>

I agree.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vman &raquo;</TD></TR><TR><TD CLASS="quote">You can still have compression with bent valves the only real way to find out if you have bent valves is to do a leakdown test.</TD></TR></TABLE>

Not with the numbers that you show. A leakdown test is more for piston rings. If you still have doubt, put a small amount of oil in each cylinder and repeat the compression results.

I still think your timing belt is off by a tooth. Find TDC with the lower timing cover installed. You can also place a Phillips screwdriver in cylinder #1 to confirm this.

 

A compression test is to primarily test for cylinder compression.

A leakdown test can check for many different problems: valve seats, cracked valve guides, bent valves, a bad spot in the cylinder wall, bad rings, and improper valve lash.

If you do a search and read a little more on both you will find that you are incorrect.

My timing is perfect, bent valves is the culprit due to the machine shop milling to much off of my head they said they took .004 off I have yet to measure the head to find out.

I think at this point I will get a thicker head gasket after I determine what they milled off my head, and replace the bent valves.

And will most definitely clay the motor before completing the rebuild.

Does anyone know what the thickness of a stock P72 head is ?

How much piston to valve clearance is there on a P72 head? I have heard .008
Just wondering if anyone could confirm this.

Thanks for all the info it has been a lot of help.
Any other suggestion would be appreciated

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vman &raquo;</TD></TR><TR><TD CLASS="quote">A leakdown test can check for many different problems: valve seats, cracked valve guides, bent valves, a bad spot in the cylinder wall, bad rings, and improper valve lash.

If you do a search and read a little more on both you will find that you are incorrect.</TD></TR></TABLE>

Leak down and compression are inherently linked.

When I had bent exhaust valves on my 1997 GS-R, it still ran, but had no low end power. The idle was rough, but certainly not like a tractor. Heck I drove it 60 miles because I had to be somewhere. It also threw engine codes 71 and 72 (cylinder #1 and #2 misfiring). Your 2000 GS-R is also OBD-II.

My compression test had numbers spanning 130-180 PSIG, all of which are lower than the typically 200psig that I see on that gauge. The car ran like it accidentially had 89 octane in it.

If your valves are bent to the point of making your car run like a tractor, you will not see the consistency and magnitude of compression numbers likeyou did. If you are still not convinced, get the leak down test done; it is cheaper than pulling the head. Does anyone have leakdown specs for the GS-R? Its not in my factory service manual.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vman &raquo;</TD></TR><TR><TD CLASS="quote">Took the valve cover off and turned the crank by hand and it sounds like compression leaks on all four cylinders???
</TD></TR></TABLE>

They all sound like they have compression leaks when turned by hand, as the rings leak. You wouldn't be able to turn the crank by hand if they didn't.

I have read the thread and I am still not clear on this point: who installed your head? You ellude to that fact that you did, but then you had someone else adjust your valves.

IMHO, if you do have bent valves, they are only slightly bent with an extraordinary uniformity between the cylinders. Adding a small amount of oil (few drops) to the cylinder when repeating the compression test will seal any small leaks and boost the compression numbers, if the leaks do exist. You can target the exhaust valves by removing the header and placing a few drops of oil on top of the valves. Your call.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vman &raquo;</TD></TR><TR><TD CLASS="quote">My timing is perfect.</TD></TR></TABLE>
I'm talking about cam timing, not ignition. If your cam is off a tooth, you can compensate to obtain correct ignition timing with the distributor, however, the car will run like a tractor. Are your distributor hold bolts in the same place as before?

 

I installed my head both times. The first time I took it to the dealership to adjust the valves because I didn't realize how easy it was. The second time I did the adjustments.

I agree it runs like it is a tooth off but everything lines up perfect. Although when I advanced the exhaust timing by 2 deg. it did seem to run a little better.

I am going to buy a leakdown tester and check it out before I pull the head just to be certain.