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I would check to see if you have some irregularity in the valve stem/retainers/keepers on cylinder 4 to help confirm bent valve. Its possible you could still have a bent valve and not see any signs, but you may with as severe as this sounds. Leakdown, may not be needed if you can see visible signs to confirm. Otherwise do the leakdown.
Thank you all for giving such quick and informative replies.
Instead of buying a junk harbor freight leak-down tester, tried to use a cheaper alternative. I purchased a short piece of air hose, a couple of fittings, and a regulator valve. I set piston #4 to TDC and set my air compressor to ~40psi. I connected the hoses and listened for leaks.
Fairly confident my valve issue is on the intake side based on this short video i took.
(You can hear some other air leaking around the fittings that i have attached because i didn't bother to put any tape on the threads.This was just for a quick test to verify the bad valve). I replicated the test on cylinder 1 to ensure that my method wasn't inherently flawed, so i set piston 1 to TDC and did the same test with no audible air leakage from the intake, exhaust, head gasket, or crank.
Unless anyone sees anything drastically wrong with this method, I think i can safely assume i have at least 1 bad intake valve and will start removing the head this weekend.
UPDATE: Hillbert replaced the entire head with an OEM unit. I know this because he sold me this car 2 months later, and DIDN'T tell me about any of the above. I just found it. Thanks, Hillbert. Oh well, nothing I can do about it.
I've been dealing with an abnormally tight intake valve on cylinder 1 with this car. The closest intake valve to the radiator. This valve will tighten over the span of 4-5k miles to a clearance gap of 0. Cylinder 4, bizarrely, has never given me a single problem. I sincerely hope that he had the cylinders numbered correctly, but it appears as if he did. The head he popped on this F20, is an AP2 assembled head. At least, I pray to god that it is. Car was pumping out a healthy 210 psi per cylinder (or thereabouts) after a valve adjustment, but presently, cylinder 1 is slightly out of spec, as I expect. Any thoughts, or ideas on what could cause a valve to tighten over this sort of a time? Is there a head break-in period I should've adhered to? The car doesn't drive poorly, and the above cylinder 4 is just fine. I've probably put around 8k miles on this car since purchased.
I've got an insane theory that cylinder 1 has a leaky and poorly patterned injector that is continually cooling that valve... mind, I do have symptoms in line with a leaking injector. Anyway, what do y'all think could be the cause of this? I haven't money-shifted the car, but I'm betting that revving AP2 intake valves to 9k is not a good thing.
Damn Vash, what are the chances?! Talk about a small world... you managed to find its history right here. Would have been better for Hillbert to have told you about what happened but what's done is done I guess...and at least he went OEM for the replacement.
Anyway, what symptoms do you experience which convince you that you have a poorly patterned injector? I doubt that the AP2 valves will be damaged by revving to 9k as I don't think the valves themselves determine max safe RPM. I could be wrong though so maybe someone else will chime in on that.
Im sorry, I was incredibly angry after seeing this bull$^# thread on here yesterday. I misspoke... I am worried about the AP2 retainers. Specifically, the intake side. My plugs are under 4000 miles old and quite black. The injectors don’t seem properly seated into the intake manifold, but I can’t be certain. I’m fairly sure they leak at low RPMs due to simply age and a slightly crumby idle.
I took the valve cover off again last night and found 6 or 7 intake valves completely tight. While I know it’s difficult to burn an intake valve, I’m just pissed. It looks like this ass didn’t even lap the valves in and in fact just put this head together himself with AP2 retainers and his old AP1 parts. I have no idea what kind of valves are in this car. They just won’t stay adjusted.
Damn I’m pissed over this.
Here’s a pic I took of the engine right after I purchased. Note the battery and tie down, and various missing parts. It’s the same car.
I can imagine how you feel
Slightly crumby idle could very well be due to an injector/s leaking.
Looks like the guy did a crappy job at replacing such important parts. If they're not staying adjusted then I'd imagine the valve guides themselves might have a part to play in that or the adjusters are bad but that is doubtful considering how straightforward their design is.
i dont think ive ever seen valves leaving an impression +1 like someone else said its likely retainers, at least thats what the ap1 is known for with these things.
If you dont have ap2 retainers and it does turn out to be that, i wouldn't make ur buddy pay the whole sum cus you should have had ap2 retainers on an ap1.
This is why i dont touch other peoples shit or drive my homies corvette even though hes offered many times.
i dont think ive ever seen valves leaving an impression +1 like someone else said its likely retainers, at least thats what the ap1 is known for with these things.
If you dont have ap2 retainers and it does turn out to be that, i wouldn't make ur buddy pay the whole sum cus you should have had ap2 retainers on an ap1.
This is why i dont touch other peoples shit or drive my homies corvette even though hes offered many times.
The stock retainers are really only a concern if the car is mechanically over revved. Aka USER error. So it is not his fault his friend money shifted his car and is not his fault it caused an issue if it was due to not swapping to AP2 retainers since it would not have ever happened if driven properly.
So yeah, if he money shifted and damaged valves it is 100% his fault as he was operating the car.
Now, whether he wants to make his buddy pay for his mistake is totally up to him and his buddy and the whole friendship thing. If it were me, I would be paying to fix my friends car without him asking if I were the one that screwed up and caused the damage. But that is just me.
Oh no, it's worse than that... The thread is from 2 years ago. The original poster, just 2 months after posting this, sold me this car without informing me of ANY of this. I just found this thread during my search for into on how to diagnose the current problem. He told me nothing about the valves, the replacement head (though I had a good idea), the money shift, etc. He totally lied by omission. I bumped it because 1)I'm having some weird problems with a tightening valve or 8, and 2) because I was a little enraged. It looks like OP and his friend go the idea to just cheap out, throw a new bare head on there and dump it off on some sucker (me). He even threw cheap-ass dirty pink antifreeze into it, used the same oil filter, and didn't bother to give me the old head, heat shields, or plug cover. I've had to put this car back together myself. OP owned this car for a grand total of 11 months and managed to do his best to destroy it.
The car has a new head, and all of the remainder, save for retainers, is AP1 valvetrain he pulled off the money-shifted head. As an aside, I'm concerned that the valves aren't tightening, rather something is off with the timing, and I've been setting the valves based on timing marks, not the cam lobes. Going by the lobes, it appears as if I can get the car properly adjusted. The car was running somewhat rich, now that the valves are just slightly loose (as I want them), the car is running lean at idle.
What a mess.
Oh crap! I guess I missed that when reading through the post (even missed the dates on the original). Really hate hearing stories like that!
Oh no, it's worse than that... The thread is from 2 years ago. The original poster, just 2 months after posting this, sold me this car without informing me of ANY of this. I just found this thread during my search for into on how to diagnose the current problem. He told me nothing about the valves, the replacement head (though I had a good idea), the money shift, etc. He totally lied by omission. I bumped it because 1)I'm having some weird problems with a tightening valve or 8, and 2) because I was a little enraged. It looks like OP and his friend go the idea to just cheap out, throw a new bare head on there and dump it off on some sucker (me). He even threw cheap-ass dirty pink antifreeze into it, used the same oil filter, and didn't bother to give me the old head, heat shields, or plug cover. I've had to put this car back together myself. OP owned this car for a grand total of 11 months and managed to do his best to destroy it.
The car has a new head, and all of the remainder, save for retainers, is AP1 valvetrain he pulled off the money-shifted head. As an aside, I'm concerned that the valves aren't tightening, rather something is off with the timing, and I've been setting the valves based on timing marks, not the cam lobes. Going by the lobes, it appears as if I can get the car properly adjusted. The car was running somewhat rich, now that the valves are just slightly loose (as I want them), the car is running lean at idle.
What a mess.
What the OP did was way out of line and down right wrong! Now you're trying to pick up the pieces. This is a really sad story. Feels bro
i dont think ive ever seen valves leaving an impression +1 like someone else said its likely retainers, at least thats what the ap1 is known for with these things.
If you dont have ap2 retainers and it does turn out to be that, i wouldn't make ur buddy pay the whole sum cus you should have had ap2 retainers on an ap1.
This is why i dont touch other peoples shit or drive my homies corvette even though hes offered many times.
Nah it's not that "he should have had AP2 retainers on an AP1". As Engifineer said the retainers aren't a problem unless a driver makes a massive error by over revving the car due to a money shift.
04-20-2017, 09:37 AM
Oh well, nothing I can do about it.
