Doing some routine maintenance and poking around under my valve covers yesterday, and saw something alarming. Pulled one rocker off to get a better look and the picture below is what I found on all of my valve tips. Configuration is a 383 stroker with 1.6 rockers, a 234 / 241 Hydraulic roller, all with about 5k miles on the clock. Seems to me the engine builder didn't properly align the rocker tips with the valve stems and they were rolling off the front edge of the valve. Found some small chips of the valves sitting on the springs and around in the drainback wells, etc. Am I needing to replace all of my valves now?? Should I be running a 1.5 rocker? Any other root cause of this?

 

You might want to take a spring off and check the guide slop and the condition of the valve spring shim. Could be some loss of valve control going on too.

Definitely correct the geometry to keep the roller from rolling off the edge. I would maybe clean up any ragged loose edges, but probably not replace the valves if they look similar to the one pictured.

 

Possible push rod length incorrect also.

 

Looks like some good sized springs there, What kind of rockers you using?
I agree that the pushrod length is wrong as suggested by RODNOK

If thats the worst one your showing us, you'd probably be OK reusing them, but I definitely try dressing the sharp edges and the larger worn area in the pic....

Look closely at the rockers as well for damage.

Thats what I'd do.....

 

Your engine builder should go back to his day job. Setting valve train geometry is easy to do and I don't think he even looked at it.

 

Thanks for the feedback guys, and sorry for the delayed reply, been super busy at work and all else has taken a back seat. I've decided to take this opportunity to address my engine combo and am considering switching up my ProComp 210cc heads with a set of AFR 195 Eliminator's. Looking for a bit more bottom end response and overall performance. I'm not looking for all out horsepower as much as low to mid-range torque. It's a street car, not a dragger, although I have considered auto-crossing it here and there.

I should probably start a new thread for this, but..... I currently have the 1.6 rockers and am wondering if I might actually make more power with a 1.5 rocker given the cam i'm running. It's a 234 / 241 at .050 with a 110LSA. Compression is 10.9:1. Could I be robbing myself from power due to my valves being open too long because of the 1.6 rocker and **** poor valve train geometry as set-up by the builder?

Also, I have an Edelbrock Performer RPM (7401) intake which I was thinking of replacing with an Edelbrock Air Gap Dual Plane (2601). I have an L88 hood so clearance isn't an issue. Wondering if this might be a good combo with the new heads, or if what I have is sufficient.

Appreciate any advice or feedback on personal experience you might have with the AFR 195's.

Thanks guys.

 

195 is a nice head thats not a great low end cam you have
assuming 350ci?
Dont waste $ on the air gap

 

Resdoggie just had good results with a Team G single plane intake.

https://www.corvetteforum.com/forums...post1593329332

That's plenty of cam and head. The AFR 195's would pick up your intake velocity plenty. That would improve your bottom end quite a bit. The cam may still work. Is it a FT or HR cam?

 

A set of lash caps would save the valves. You MUST check the geometry and pushrod length. I too am not sure you need or want 1.6 rockers with that cam, better check the numbers.

 

On the intake question - of those two intakes you listed the 7401 is the better choice - I have run it with 195's. The port size is nearly as large as the 7501 RPM air gap (7501 is next step up from the 2601 you mentioned).

If you want to stick with a dual plan the sake of bottom end torque ,then the 7501 is my first choice (assuming you don't have a spreadbore carb), and the 7401 is my second (can run either a square or spreadbore carb) - I have used both in the past. I am not sure you will feel the difference between those two while just driving around town. Port size is slightly larger in the 7501, but not by much. I definitely would not go smaller than a 7401 with AFR 195 heads.

 

WOW! I would tear down the heads completely and go through it with a fine tooth comb. It would be better to do that at a cost of only a few dollars to put it all back together vs. ignoring it and costing you an entire motor rebuild cost.

Based only on what you presented, it would appear that the valve train geometry is way off which again only based on face value what was presented I would guess that your push rods are the incorrect length or something else is terribly wrong. Hope you get the issue resolved fast better the motor gets hurt.

BTW: the AFR 195 Eliminators are a great head with a slightly larger 2.05 intake valve than most heads in that size which are usually 2.02. I run DartPro1 heads and like them, but I'm also changing to AFR after about eight years with Dart. My plan with the AFR heads is a complete tear down before they go on the motor to ensure they are correct in spec since a lot of "production" heads from major manufacturer's have issue from right out of the box installations. Several items that is going to get checked for sure are the guides and the valve seat run out among other things. If you're going to spend good cash on aftermarket heads, it's worth the time to have this checked. I'll also be milling the heads down to 62cc vs. the 65cc the heads come with to keep everything in-line with my current Dart head configuration. So the tear down really isn't an issue since they will be torn down anyway. Good luck with your motor.

 

Upon reading this over again. I would suggest doing what you are thinking w the 1.5 rockers(full roller) . Dress up the valves a little, set the 1.5's on and you might just be good to go. The 1.5's should give you a better pattern on the valve tip and build your torque @ lower rpm. If any of those chips made it to the bottom end they will be stuck in the oil filter. How is the oil pressure ?

 

Hey Reelav8r, the Cam is Hydraulic Roller.

cooper9811, sounds like I will stick with the 7104 based on the opinions i'm getting here, can always do something with that later. Thx

I may pick up a set of 1.5 rockers and correct pushrods just to see what kind of difference they make with my existing combo. I will then have a better apples-to-apples comparison for what the AFR 195s' bring to the table. Oil pressure is good, right around 45psi at idle and 70psi at cruise. Thanks Pop Chevy.

The AFR's are upgradeable to 7/16" rocker studs and I see no reason not to with only a $45 premium, but setting up valve-train is all new to me, is there a downside to the larger stud? Any reason to upgrade to titanium retainers if I'm keeping RPM to 6K and under? Stud girdle necessary or beneficial at these RPM's and open seat pressure of ~350 pounds?

Thanks guys!

 

You may have bigger problems than just the valves. Valve tips are made of Stellite. It is the hardest metal in your entire engine. It looks like there are a lot of pieces some probably have made it to the oil pan. It is very likely they have been thrown around getting to places like pistons and cylinders where the extremely the hard pieces could cause a lot of damage. Your oil pump also picks up unfiltered oil before sending it to the oil filter. You could have damage there too. If they got by the bypass in the oil filter, you have damage to the crank and bearings. I've seen metal filings do a lot of damage in engines many times and Stellite can really tear things up!

Mike

 

I'm using AFR 180's shimmed .015 on the springs for a 155 seat 355 open iirc. Also using 7/16" studs. No problems with spring control with that combo and 6000 RPM on my 350.
Sorry, I see that your initial post stated HR cam.
That duration on a roller cam is somewhat aggressive if your looking for bottom torque.
However I think with the right velocity in the head and the intake it would do real well on a 383. What are the lift and LSA for that cam? Should deliver good midrange and good top as well at least just based on duration. Little hard to say without the rest of the cam specs.
I'd probably want a higher stall that stock torque converter if we're talking an automatic.

 

v2racing, I was leery of doing any grinding or cleanup on the valve stems because of the metal type. AFR's own installation instructions for their heads state say "DO NOT GRIND VALVES", and they go on to explain that it will cause them to mushroom over and cause severe engine damage. I'll be pulling the pan to get a thorough look at everything as every valve tip looks like the one in the picture above, and you can actually see a metal flake on the keeper. probably not good......

REELAV8R, I also thought that the duration is a bit high for good bottom end, so I called Howard's Cam's (that's what I have in the motor now) to discuss my combo and see what they might suggest I do differently to improve on it. I talked with Eric (awesome guy, gave me a lot of his time and volunteered tons of great info. Highly recommended!), and he actually thought my combo should be a 'beast' down low with the 233/241 duration @.050, .530 / .545 lift with 1.5 rockers (I have 1.6 installed), and a 110LSA at 10.9:1 compression, converter is 2800ish stall. He suggested I do a compression test on a few cylinders to verify that I was in the 170-180psi range, and if more like 150psi, the builder may not have degreed the cam correctly which would have a dramatic effect on overall performance. Can I do that with the motor in the car?? Don't really want to pull it?

Eric also said that he would be concerned about using a smaller cam because with my high compression, keeping the valves closed longer will build even more cylinder pressure, and therefore leave me vulnerable to detonation issues. Interesting conundrum, I guess.

I'm going to do the compression test with my valves as-is, then I'm going to get the right size push-rods for my existing 1.6 rockers and do the compression testing again. finally, I thought I would install some 1.5 rockers with the correct push-rods on a couple of cylinders and test again to see what kind of difference there might be. More curiosity than anything, and maybe something useful for someone else here.