History repeats itself. The turbo car is broken again and will be for a while..

Interresting... That's exactly the wild thoery I had way back at start of this thread...

Here is a picture of the cam card. I honestly don't know that much about cams, but it was ground by Crower specifically for this application..

You may have to save it and blow it up to read it..

The cam was installed on a stock timing set.

 

Don't really know what kind of events you would be describing. As stated, the car runs perfectly.

 

As far as valve train geometry goes, Maybe I'm missing something.. The roller tip is on top of the valve and is slightly off center toward the rocker arm.. As it opens it rolls across center to slightly on the other side of the valve tip and then back as it closes?? Is there more to it than that??

 

No, you're good.

Devon

 

ICL is on 110 which is good. Most cams of that size are on 108, so no problem there. The LSA is 114 which is wide, but really common for a turbo cam. As long as the cam degrees to specs, I just don't see a problem with the grind. Some specs I can't see is the duration at .050". The picture is too blurry.

 

224 intake 230 exhaust.. It's little

 

That is strange because the advertised duration says:
Intake 284
Exhaust 276

It is unusual the exhaust would have so much more aggressive ramp profile than the intake.

 

Apparently too blurry for me too.. 226 intake 210 exhaust holding the card in my hand. at .050..

My SWAG is that the exhaust pressure is high and the vavle tries to open accompanied by the fact that that rocker hangs off the end of the shaft and has a twisting force as well as a lever effect and is just to great for the fastener. I ran this app. for several months NA and never had a problem. Soon as I started to get a good tune with the boost the rear passenger side broke..

Don't know.. Long story short. Find a better way to attach it and it will work like a champ. Not sure why it works for others though. I will say I have not that many miles, but I've been through 6 gallons of metahnol (-40 washer fluid) since I installed that kit. Thats a 10 GPH nozzle so I've been in the boost for 30+ minutes. That's a good bit of time with your foot on the floor hanging on..

 

On another note from the Fastenal website..

Flat head screws are limited by configuration in their tensile strength capability.

 

Perhaps you could fabricate a longer plate and attach it to the end of the heads vertical surface. That should do it.

 

Please tell me you're not using flat head screws to hold those plates down??

Flat head screws are pretty much NEVER higher than grade 5 and often grade 3 fasteners. If that's what you're using, go to a countersunk socket head capscrew and you'll probably have no more troubles. I think they are rated grade 9 or 10.

JB

 

This is what I was using this time.. What came with the setup I believe was stainless. I can't find any fasteners like this rated at grade 8 or above.

http://www.fastenal.com/web/search/...ket-cap-screws/_/N-gj4wbuZjuevz3Zjue0jq&Nty=0

 

Oh well. Out with the engine. No way is this coming apart in the car. With the engine out I may be able to fix it without pulling the heads??

 

The set up might be a good idea and saves a lot of money but with 2 failures now and you have to pull the motor out I think you would have been better off spending the extra money and just getting a set of TA shaft mount rollers. Now you are spending a lot of time and money to keep the alternate system fixed. Plus now you have to use this system and you can't go back to the old way which would cost even more money.

 

What if you had the heads machined for studs and bolted them down? As I understand it, there's different types of stress that are loaded on a fastener when it's a stud/nut as opposed to a bolt. ARP has a page discussing the basics.

 

Won't fit..

 

Thank you Dr. Hindsight..

 

Well. It's on the stand. Now the question is, what am I gonna do with it???

 

James has broken I think 6 rockers, as well as snapped the rocker shafts in half. He's running the factory setup. I'm guessing the TA setup has a stronger shaft that would have saved him all this hassle? Funny how everyone is SO sure it is the rocker conversion, not something else that would be stressing any valvetrain.

 

So, how can I find the answer????? I guess James and I are the only ones really beating up a turbo Buick setup. And I can guarantee I'm beating on it harder than he is. The engine is on the stand, but I really don't know what to do about it. I'm truely at a loss. Why does James keep breaking ther valvetrain?? How do the chevy guys make so much power without breaking stuff?????? I do have a dual pattern tranny..

I don't know.. I don't know what to do either..