I have about 17k on my build. All brand new engine dart block afr head 414. I pulled my rockers due to noise and found a couple of valves like this. Has anyone had problems with AFR supplied valves?

 

Whats your pushrod length and diameter? How high rpm has motor seen? Any over revs?

What lifters and oil weight?


Looks like geometry issue leading to float

 

Looks definitely like float; I don't really see a geometry issue in the pic, but we all know how that is.

What springs are on it? What cam? What RPMs has it run?

 

Sorry to read the bad news with your top notch build. All i can do is list possible causes. Vlv float - excessive rpm/weak spring, coil bind/retainer hitting vlv seal - spring height to short, wrong preload, rocker arms adj nut slipping/loose.

Hope this helps.

 

In addition to above, does AFR recommend the use of hardened lash caps on those heads?

 

Yrs ago, AFR did have a valve tip hardness issue that cost them a chunk of change. This looks kind of like that.

 

FWIW my AFRs are pre-eliminator and my valve tips look fine. They are the competition type though so they may have different valves.

 

Its either faulty valve or some kind of float issue hammering the tips. Valve shows several witness marks so it looks as if it was moving around from float.

Now if those are 8019 springs and that cam, i wouldnt expect float. So makes me think maybe pushrod length/geometry issue

 

Possible that the roller surface isn't parallel with the valve's contact surface and that's why the damaged surface looks triangular? Maybe from a bent stud or bad rocker. which cylinder number valves are they and do they all look the same?

Mine is probably the least likely, I'm just adding an option.

 

Thanks for the input. Ok here the info.

AFR installed 8019 springs with Comp Cam 236/242 @ .600/608. Comp promag 1.6 RR 5/16PR. Comp cam Short travel "race" retro hydraulic rollers with ~1/4 turn (0.012") preload. This is an intake valve which makes the rocker kick out some. 10/40 conventional oil. Yes, may have been over revved a time or two but nothing too severe. I generally shift @ 56-5800 and have missed a shift or two. The contact pattern looks good and centered on the other tips and is ~.060-080" wide. A few have turned 90' at some point cause the pattern is butterfly shaped. Cam is reduced BC and the engine build sheet says .860. It looks very small through the lifter valley screens and the retro link bars only have about ~.100" clearance at the Dart lifter bosses.

Heads were Mfd in mid 2014 which was during the "back order" of castings which lasted a couple of month. I mention that because I know how production goes when a component holds up production then comes in. A lot of orders get rushed out the door. I looked into adding the lash caps as a Band-Aid and bought a set of 8mm caps. Interesting thing is most are tight but a few are loose. I wonder if it's possible some of the valves are 5/16" and some are 8mm??? May explain why I have a lot of build up on the back of some of the intake valves. The motor only has 17K on it and looks like 100K.

What brought all this up was a valve train noise that ended up being a push rod/rocker wear problem that in turn also revealed a broken lifter cup, all on the same valve but not the one in the picture.

 

Actually, I think that is the MOST likely. The rocker loaded and failed one edge of the valve tip, and it progressed from there. Bent stud, bad (off-axis or oversized) valve guide, wrong diameter valve stem,..?

 

That base circle is tiny!! Thats gonna make things hard on the lifters and springs as it is. I didnt realize that cam had to have such a tiny circle

 

Yeah, that's a tiny base circle for a cam. I'm going to try and confirm it with Comp. It's "supposed" to be .900" and I am not convinced it was necessary. The shop who built this engine does mostly race motors where longevity isn't a priority. I think they just used the small BC for convenience. I have what should be a bullet proof bottom end but I have always had problems with hyd roller setups. This one and the previous motor. Same type issues.

So here's what I have. A 414CI motor with 17k miles and the valve tips are worn, 1 busted hyd roller pushrod cup, galled pushrod and rocker. I'm concerned the valves may be mix-matched and probably worn guides. Otherwise it runs great!

My first option is replace the lifter (pair) push rod and rocker. Leave the valves and add lash caps. I'll probably need longer pushrods but that will leave me at about $250 to get back up and running until I pull it down at a later date.

The other option is to fix it all. If I pull the heads I may as well pull the motor so I can get to the pan and see what I required in regard to cam/rod clearance. The reason here would be to optimize the cam size and either build it to street friendly trim or go with a solid cam, flat or roller. I just haven't had much success with the hot street-near race hydraulic rollers. I'm sure people have done it with success but there has to be a better combination for me. Thoughts?

 

I agree you ideally want the largest base circle and lifter you can fit. It leads to longevity as stresses are lower on the larger stuff. Less angle of rise to the lifter, etc

But breaking lifter and pushrod damage seems very strange. Might want to double check the alignment and geometry of everything, make sure pushrods arent binding, and studs arent flexing around, etc.

 

Sorry to read your problems are growing but i think u need more info before spending more $$ or effort. 0.600" lift is quite a lot for a street cam. If it were mine i would check all the vlv train clearances - springs, rockers, guide plates, preload. And then pull the springs and test them - mostly the ones with the failures. Im thinking your springs were good as installed but 17K mi has done them in. Also u start to have a lot more vlv train flex w/0.600" lift and springs. Consider a smaller cam?? Or how bout just 1.5 rocker arms??

Good luck and please post what u find.

 

What do you think about my "repair" option of adding lash caps to a valve that already has damage? I really don't want to pull it down right now.

If/when I do go back through it I am seriously considering a cam change. Heck, if I'm floating valves at 55-6000 I may as well build a torque motor. If I can make good mid-power it'll probably be a better driver. On the other hand if I choose to keep the duration/lift up there I may go solid. I have heard of problems with solid rollers on the street so I may just use a solid flat tappet. ???

I built a large CI motor with the goal of making good power in a streetable, reliable package and so far I haven't fully met those goals. 17k and I'm back into it so there goes reliability. It did make good power (no dyno #'s) and I am satisfied with the performance. Streetability was pretty fair and mileage was decent at 15 combined and closer to 20 on the highway. After a year and a half of tuning I can't get rid of some quirks at ~1800 light throttle but overall it's fun to drive. I'm thinking I could still make good power at lower rpm and make it more reliable.

 

You know I never really thought about the miles affect on the springs. Good point. Any yes, I have/am considering a more reasonable cam. If you read my prior post I am willing to trade some HP/RPM potential for a more reliable and streetable combination. You are absolutely right about rechecking everything. Do you think the 1.5's would relieve a significant amount of stress?

 

What cam lobes did you use?

 

Comp Cams QXI series

CS13571N Int 291Adv 236 @050 155 @200 .375 lobe .600 w/1.6
CS13574N Exh 297Adv 242 @050 161 @200 .380 lobe .608 w/1.6

Ground on 112 LSA 108

I'm trying to verify the exact base sircle size, it's supposed to be .900" but build sheet states .860". These are high lift lobes but not quite as aggressive as the XFI lobes. They are supposed to be med intensity.

 

That cardoO guy is right about the springs. With that cam, I'd have thrown them out at about the 10k mile mark.
For now, I'd do as you're thinking: remove the springs, check for valve/guide play, check all components for straightness/clearances/geometry/damage, go back together with new springs, 1.5 rockers and lash caps. I don't see that valve tip damage harming anything under lashcaps.

 

Still looks like valve float to me, NOT a geometry problem, just based off of what I see.

I'm seeing a SPRING problem: the valves are floating. Bouncing off the seat when they should be closing. I know AFR was using K-Motion springs at one time, if that's what those are, then they are TRASH.

I don't have the published specs for the springs you now have right in front of me ATM; but, I can tell you about what I think you need:

Installed height 1.800 - 1.850", coil bind 1.150" MAX, 125 - 140 lbs on the seat, 375 - 425 @ .600. If it was mine I'd be looking for a way to get 1.55" OD springs on there, or some of the beehives for big LSx setups. Call Comp and ask, then DON'T go with their "minimum" recommendation, get them to up it a notch. You know, like how you look in their catalog and it shows like "standard" and "premium" or some such; go with the "premium".

Lash caps should be OK on top of what's there; looks like there's enough of the flat surface of the valve left for one to seat on it correctly. (if the tip was rounded, it'd be garbage)

Small base circle may not be "ideal" or "necessary" for the rest of the setup, but isn't the cause of THIS problem. If you have lobe & roller failure, then yeah, maybe.

Those aren't just excruciatingly intense lobes like on the outer edge of what's possible or anything, with proper springs 6500 rpm should be no problem. Frankly I'd leave it in there if you like the way it runs.

 

Fyi Comp shows my base circle is 0.844" even the Comp rep said "yeah that's pretty small". He said it's likely that size because of the lobe we had selected and the core they used forced them to go that far down to get the lobe profile to fit. Heck if I had known all that I would have gone with less lift. Anyway, I'm gonna just check everything out and get it going for now and plan a re-do soon. At that time I'll pull the motor so I can actually measure rod clearance and go from there. Freshen up the heads and put in a less aggressive lobe cam.

Funny how now all the same people I spoke with when I was specking out this combo now say I need less cam for longer life. I guess the idea of a daily driver means different things to different people. Unless it's raining or snowing or I have to haul something I'm driving this IROC. 12k/yr is a daily driver to me and I guess .600" lift is too much unless you want to go back through things every year or two.

 

I just read your post Sofa, thanks for the input. I appreciate the detail. I am going to "redo" what I have for now and yes, I do like the way it runs. Interesting you mention the beehives because it seems most of the catalog cams similar to mine recommend them.

And I appreciate everyone's input. Sounds like I may have experience some float and that possibly caused all my problems. The Comp rep did mention something interesting I believe he called it "free rev" floating. When you blip the throttle or take off in first gear and the rpms climb rapidly that it can cause dynamic situations which can float or bounce the valves even though you aren't near max rpm for steady state conditions. What do you think about that scenario?

 

Its not the lift thats a problem. You can get that to live but i'm not so sure you can do it with .844 base circle and those lobes

I would lean towards whatever the fattest base circle you can fit and maybe something like a magnum high lift lobe

 

The 8019 afr springs are a PAC dual spring and very nice spring. 8017's also should be a PAC spring just lower seat pressures. The 8019 is the good spring for a hyd roller deal but a .844 base circle aggressive lobe like qxi is not gonna be easy to control.

 

Take a look at the AFR lash cap installed. There are a couple of questions. First, how tight should the cap fit onto the valve stem? There are a few I actually have to press on with my finger and others just fall on. Second, is the gap between the bottom of the cap and the retainer ok? It is about .050". I have seen some keepers which have a relief for the cap to slip into covering the entire stem. Is the type I have a different style or is this wrong. Bottom line is can/should I run it like this?

 

Mine slip on fairly easily and not all that much pressure required.

The offset locks used to set spring install heights need the recess for the lash caps because the stem sits almost even with the retainer surface. Rocker arm would hit retainer. So cap is used to keep rocker off the retainer

On yours it should be ok. Make sure you cant wiggle the valve assembly in the guide. Dont want to run that setup if guides are worn

 

Yes, these are AFR installed 8019 springs. I have no reason to believe otherwise yet. Do you think I could have actually worn these out in 17k miles? Otherwise I have over revved it more than I imagined. I don't actually trust the factory tach so I double check it with the EBL logs. Is it possible I am shifting higher than EBL can log? For example in first I've hit 6500 quicker than the log can catch it. I normally shift at 5800 ish. Usually a little less sometimes a little more. I don't think I have ever logged over 6200. I either have really bad dynamic condition or have zipped it a time or three when I wasn't logging. These springs should have handled this RPM range if everything else is correct.

 

How "tight" do they fit? can you move them any side to side?

 

They arent snug requiring a press fit by any means but they are not sloppy loose either. Tiny bit of movement


As far as spring life goes, on that small base circle and some over revs i would pop a spring or two off, one exhaust one intake and measure the pressures. Thats the only way to tell.

It wasnt uncommon for guys with aggressive cams to change springs every 12-15k miles on hot street strip stuff, some longer life in milder lobes 20-25k