Brice

I've tuned a friend with 224/228/114, AFR 205 milled 61cc, Fast Intake ported by Tony Mamo, FAST Injectors, new ported all pump, and all the usual stuff.
The car runs fine, 425 rwhp on mustang dyno, 12.8 AFR, 24 degres timing, no knock retards.

The car run strong ... but after 6 month of daily driving and 15 minutes of road racing. (the car has been already 2 times on tracks without problems)

http://www.youtube.com/watch?v=elCuvBpzFbE

Here is the results :












My friend is very very sad ... And I'm very confused ...
French haters say that US V8 with H/C aren't designed to run @ 6500 and that they should not see a track ...



What do you think about the causes ???? I have no clue ... bad parts ? bad installation ? bad use ?

And now, what's next ? new lower end ? strocker ? forged ? crate engine ?

We want a reliable engine that can see a track 3-4 days a year that's why we have taken the best parts we could find for this setup !

davidws6

iTrader: (36)

Were the springs upgraded upon cam install?

I'd search for a decent price on a crate engine.

I have one of those cams I want to try in a stock cube eng, someday....

Brice

Of course spring were updated. I don't know which ones, they went with the heads, I will ask to my friend.

LS1-450

iTrader: (33)

Fix or replace the head, replace all springs, replace damaged piston, rod, rod bearing & check crank & crank bearing, confirm proper pushrod/rocker arm geometry.

Why listen to a Frenchman? It would be the same as taking advice from a Woman.

Valve dropped due to a broken or damaged spring. Who set up the valvetrain w/ the new cam? Could be that incorrect length pushrods were used. Was the wipe pattern on the valve stems confirmed to be centered & narrow? What was the pre-loas on the lifter set to? Did he over rev the engine or miss a shift badly a few times during the engines life, before this happened? Did you set the rev limiter & fuel cut off just above the valvetrain's safe operating RPM?

Brice

rev limitor and fuel cut off set to 6600 rpm. I will let my friend gilles answer to the question, because I haven't all the answers.
Here is his list of parts :

Culasse AFR LS1 205cc fully CNC ported, 66cc chambers, Small Bore,complete w/ parts
Milled to 61cc
Cometic 5.7L Multi-Layer Steel Cylinder Head Gaskets (.040")
Comp Cams Camshaft - 224/228 .581/.588 114 Tiges : Patriot Pushrods - 7.500
Comp Cams Pushrod Length Checker
GM LS7 Lifters
ASP Crank Pulley C5
NGK Spark Plugs -
SLP 160* Thermostat
SLP LS1 Oil Pump - High Volume
GM LS2 Timing Chain
Yella Terra Ultralight Rockers - Bolt on shaft type non adjustable 1.7:1
FAST 36# Injectors
Serpentine Belt for C5, using ASP Pulley
AC Belt for C5, using ASP Pulley
Pipe Fast 92 intake modified by Toni Mamo
Trottle body LS2 ported by TonyMamo
Textralia Z Grip Clutch
Long tube american American Headers 1-3/4.
Muffler Magnaflow
Plx Wideband
Vararam VR-B2


Here is the video of the damage time (0'30)
http://www.youtube.com/watch?v=K9HGqB2qZ94

LS1-450

iTrader: (33)

^^^

Info that you have listed all looks good. Broken spring is the most likely cause of the dropped valve. Could have been a bad spring (part) issue, high revving downshift or miss shifts sometime during its' life. I have almost that exact set up. Other thing to check is to make sure of the pushrod length (a second check).

matt1289

Wouldn't you commonly end up with a shorter push rod with milled heads? It really seems like the push rods are too long but I could be wrong.

LS1-450

iTrader: (33)

Not necessarily w/ an aftermarket cam due to the smaller cam base circle. Although, I do agree & have noted that another pushrod check is in order; with full attention to valve wipe pattern & the lifter pre-poad.

LS1-450

iTrader: (33)

Just spoke w/ AFR. The springs need to be 8019. The springs that come w/ the heads are rated to an .060" lift based on coil bind only, not necessarily cam lift, 8019's are usually needed while using cams w/lifts in the .580's-.590's. AFR asked about the duration @ .050" & I wasn't sure. Anyway, confirm that the springs are 8019's.

AFR stated that it is the acceleration of the valve that requires the greater resistance from the 8019 spring. If the standard lift .600" AFR head springs are used, it is likely that valve float will cause the valve to hit the piston @ higher RPM's.

themonkeyman89

iTrader: (2)

Out of curiosity, where did you find the head of the valve? Was it shoved back into the manifold?

fccs

iTrader: (26)

Weird question but whats up with you HUD? It's reading from 10mph to 190mph at all random times lol

LS1-NAVY

iTrader: (1)

^^i bet its in kph not mph and when it goes past 199 it resets back to 0 so when it said 10 it was 210 thats just my guess

Soul TKR

iTrader: (4)

there's something about carnage pics that I just feed off of.... as long as they aren't mine

sorry to hear about the mishap

Brice

Duration is .588/.588

btw, my friend didn't know about the springs on his AFR (they were installed).
Could you identify them on the pic ?

Don't know about the springs
That all I know :
"AFR LS1 205cc fully CNC ported, 66cc chambers, Small Bore,complete w/ parts"
And that the vendor is Hinsonsupercar.

Bracket Boy

iTrader: (2)

Milling the heads from 66 to 61 and using a .040 gasket sure looks like you might have some valve to piston clearance issues. Advancing the cam could also play a role.
Just an observation.
Jay

LS1-450

iTrader: (33)

My opinion, from the information noted, is that the heads may have had 8017 springs & not 8019 springs. The only way to tell the difference (that I know of) is to measure the installed seat pressure. 8017 seat pressure is 135# & 8019 seat pressure is 155#. Hinsonsupercar should be able to tell your friend which springs were used or someone can measure the seat pressure to confirm.

Brice

According to the AFR website, 8019 have red stripes ...
well on the spring pic, I don't see red stripes !!!!
I've told my friend to have a closer look.

Thank you LS1-450, that's an excellent information !