Pics of my cracked AP1 valve retainers
02-18-2011, 07:18 PM
#1
Registered User
Thread Starter
Pics of my cracked AP1 valve retainers
In case anyone wasn't following the BlackTrax thread and might not be on top of the issue of cracked valve retainers in AP1's, I wanted to start a new thread to share my experience with you. If you have an AP1 and you've never had your valves adjusted since you've owned it, I am a good excuse to get one done while getting your retainers inspected in the process.
I have driven my car hard, but not abused it. It has not been mechanically over-revved since I've owned it. There were no signs of any problems, no weird noises or anything. It ran strong, etc. My car has low miles (34,000 now, 27,000 when I bought it), and was purchased from a trusted seller who babied it. I got a pre-purchase inspection from a trusted local S2k mechanic, and the car had good compression. But still, there was a silent killer lurking under my valve cover. LOL.
When the engine is over-revved AP1 retainers can crack, but from what I understand, it should take a while for the cracks to get as bad as mine are, so it could have been over-revved long ago in the car's history. I am the 3rd owner. It could have been over-revved by the first owner, or even some random person at the dealership when it had 5 miles on the clock.
It can take thousands of miles for the retainers to finally give out after an over-rev but once Aki at BlackTrax discovered it, I didn't want to find out how much longer they could last. All I know is I had a ticking timebomb under my hood, even though my car had no symptoms that it would have ultimately gone kaboom if this problem hadn't been caught. Anyway, check out the retainers:
In the pics, the lower row of 8 are from the intake side, and the top row of 8 are from the exhaust side. The 4 on the right are from cylinder #4 (exhaust on top, intake on the bottom). The rest of the retainers I just arranged in order of how badly they are damaged. Worse to better goes from right to left. Note that these retainers are all upside down relative to how they sit in the engine. So we are looking at the underside, which you cannot see without taking them off. The top side doesn't show any damage. All 8 intake retainers are cracked to some degree, the least of which you can hardly see. At least 4 exhaust are cracked, although some are very faint.
I was actually really lucky that Aki caught my cracked exhaust valve retainers because from just a visual inspection, the exhaust valves did not appear sunken. But after taking measurements, he discovered the exhaust side had the same problem as the intake side, just not as bad.
The 16 AP1 retainers above have now been replaced with 8 AP2 retainers on the intake side, and 8 AP1 retainers on the exhaust side. (See links below for why I didn't upgrade the exhaust side to AP2's.) Fortunately for me, there was no other damage to the engine. Valves were straight, no scoring on the cams or the roller rockers, good leakdown numbers (all under 3%).
I just want to say, thank you very much to Aki and Jei at BlackTrax! I really appreciate both the Valve Adjustment Day, and the fact that you squeezed me into your schedule and let me leave my car there when the issue was discovered. It was very reassuring to know my car was in good hands with you guys.
I also owe a dept of gratitude to Billman250, as well as the others who have shed light on this issue on S2ki. When I learned that I had cracked retainers, I read a lot of old posts on S2ki about the issue. Billman250 I believe was the first to discover this issue, and has written a lot about it, sharing what he's learned from inspecting 100's of S2k's for this problem. Although he has found dozens I believe with cracked intake retainers, he has only found cracked exhaust retainers on one. So I kind of freaked out when I found out I had cracked exhaust retainers. LOL. Anyway, he took the time out to answer some of my questions on very short notice, and I sincerely appreciate that.
Anyway, S2ki, once again, rocks. If it wasn't on the people on this forum, my engine would surely have been toast way too early on in its life.
So, if you have an AP1, I would highly recommend getting a valve adjustment and retainer inspection if you never have done so since you owned it.
I'll post some links to other threads in a bit in case you want to do more reading.
I have driven my car hard, but not abused it. It has not been mechanically over-revved since I've owned it. There were no signs of any problems, no weird noises or anything. It ran strong, etc. My car has low miles (34,000 now, 27,000 when I bought it), and was purchased from a trusted seller who babied it. I got a pre-purchase inspection from a trusted local S2k mechanic, and the car had good compression. But still, there was a silent killer lurking under my valve cover. LOL.
When the engine is over-revved AP1 retainers can crack, but from what I understand, it should take a while for the cracks to get as bad as mine are, so it could have been over-revved long ago in the car's history. I am the 3rd owner. It could have been over-revved by the first owner, or even some random person at the dealership when it had 5 miles on the clock.
It can take thousands of miles for the retainers to finally give out after an over-rev but once Aki at BlackTrax discovered it, I didn't want to find out how much longer they could last. All I know is I had a ticking timebomb under my hood, even though my car had no symptoms that it would have ultimately gone kaboom if this problem hadn't been caught. Anyway, check out the retainers:
In the pics, the lower row of 8 are from the intake side, and the top row of 8 are from the exhaust side. The 4 on the right are from cylinder #4 (exhaust on top, intake on the bottom). The rest of the retainers I just arranged in order of how badly they are damaged. Worse to better goes from right to left. Note that these retainers are all upside down relative to how they sit in the engine. So we are looking at the underside, which you cannot see without taking them off. The top side doesn't show any damage. All 8 intake retainers are cracked to some degree, the least of which you can hardly see. At least 4 exhaust are cracked, although some are very faint.
I was actually really lucky that Aki caught my cracked exhaust valve retainers because from just a visual inspection, the exhaust valves did not appear sunken. But after taking measurements, he discovered the exhaust side had the same problem as the intake side, just not as bad.
The 16 AP1 retainers above have now been replaced with 8 AP2 retainers on the intake side, and 8 AP1 retainers on the exhaust side. (See links below for why I didn't upgrade the exhaust side to AP2's.) Fortunately for me, there was no other damage to the engine. Valves were straight, no scoring on the cams or the roller rockers, good leakdown numbers (all under 3%).
I just want to say, thank you very much to Aki and Jei at BlackTrax! I really appreciate both the Valve Adjustment Day, and the fact that you squeezed me into your schedule and let me leave my car there when the issue was discovered. It was very reassuring to know my car was in good hands with you guys.
I also owe a dept of gratitude to Billman250, as well as the others who have shed light on this issue on S2ki. When I learned that I had cracked retainers, I read a lot of old posts on S2ki about the issue. Billman250 I believe was the first to discover this issue, and has written a lot about it, sharing what he's learned from inspecting 100's of S2k's for this problem. Although he has found dozens I believe with cracked intake retainers, he has only found cracked exhaust retainers on one. So I kind of freaked out when I found out I had cracked exhaust retainers. LOL. Anyway, he took the time out to answer some of my questions on very short notice, and I sincerely appreciate that.
Anyway, S2ki, once again, rocks. If it wasn't on the people on this forum, my engine would surely have been toast way too early on in its life.
So, if you have an AP1, I would highly recommend getting a valve adjustment and retainer inspection if you never have done so since you owned it.
I'll post some links to other threads in a bit in case you want to do more reading.
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pezee (02-12-2017)
02-18-2011, 07:25 PM
#2
Registered User
Thread Starter
Here are some links I found informative while studying up on the AP1 cracked retainer issue:
Why upgrade an F20C with cracked retainers to AP2 retainers:
https://www.s2ki.com/forums/index.php?showt...0&#entry9042063
Theory as to why it may be better to keep AP1 retainers on the exhaust side of an F20C:
https://www.s2ki.com/forums/index.php?showt...&#entry19331315
https://www.s2ki.com/forums/index.php?showt...&#entry18658304
DIY engine / valve retainer inspection and test:
https://www.s2ki.com/home/2010/08/03/over-r...ction-and-test/
DIY retainer replacement thread, with background of the issue:
https://www.s2ki.com/forums/index.ph...ic=569714&st=0
Why upgrade an F20C with cracked retainers to AP2 retainers:
https://www.s2ki.com/forums/index.php?showt...0&#entry9042063
Theory as to why it may be better to keep AP1 retainers on the exhaust side of an F20C:
https://www.s2ki.com/forums/index.php?showt...&#entry19331315
https://www.s2ki.com/forums/index.php?showt...&#entry18658304
DIY engine / valve retainer inspection and test:
https://www.s2ki.com/home/2010/08/03/over-r...ction-and-test/
DIY retainer replacement thread, with background of the issue:
https://www.s2ki.com/forums/index.ph...ic=569714&st=0
02-18-2011, 07:38 PM
#5
Former Moderator
^ you're welcome
By a qualified shop that knows what to look for 
BT
Originally Posted by obsess2k'ed,Feb 18 2011, 08:18 PM
So, if you have an AP1, I would highly recommend getting a valve adjustment and retainer inspection if you never have done so since you owned it.
BT
Trending Topics
02-18-2011, 07:56 PM
#8
Former Moderator
Originally Posted by hellaSleepy,Feb 18 2011, 08:45 PM
Curious, what kinda damage would one be looking at if say it fails
Here's a link of a motor that had a bad over rev
https://www.s2ki.com/forums/index.php?showt...post&p=11188882
02-18-2011, 09:20 PM
#9
Registered User
Thread Starter
Originally Posted by hom11866,Feb 18 2011, 08:44 PM
How much would that be for the brand new AP2 Retainers?
But I'd definitely recommend starting with a valve adjustment and retainer inspection, and then go from there.
02-18-2011, 09:31 PM
#10
Registered User
Thread Starter
Also, if you are thinking about upgrading retainers, I'd definitely encourage you to check over those links I posted. I don't think anyone is recommending upgrading unless your existing retainers are already cracked. So the most important thing is just to get a valve adjustment & retainer inspection to make sure your existing ones are not failing.
The other thing is if you do need to swap out retainers, you may want to consider doing as I did: AP2 retainers on the intake side, and AP1 retainers on the exhaust side. The reasoning for this is also explained in the links I posted above. Not that I mind explaining it, but I just don't want to get myself in trouble by explaining it wrong.
Opinions may vary though and some have gone with AP2 retainers on both sides. However, the theory I have read as to why AP1 retainers are better on the exhaust side on an F20C makes sense to me, so I went with that.
The other thing is if you do need to swap out retainers, you may want to consider doing as I did: AP2 retainers on the intake side, and AP1 retainers on the exhaust side. The reasoning for this is also explained in the links I posted above. Not that I mind explaining it, but I just don't want to get myself in trouble by explaining it wrong.
Opinions may vary though and some have gone with AP2 retainers on both sides. However, the theory I have read as to why AP1 retainers are better on the exhaust side on an F20C makes sense to me, so I went with that.