Yellow Bullet Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
1,570 Posts
Discussion Starter #1
I have a BAE 5 screw blown alcohol hemi with t&d rocker gear. I had a camshaft ground specifically to be easy on parts.
This thing kills valve springs compared to other guys that run a lot harder.
I bought solid tool steel pushrods and the springs have gone from 400 to 530 lbs seat and 1300 open.
The increase in pressure showed no major improvement. I normally shift at 9300 but have been to 10200 on the limiter and everything in the engine looks happy except the valve spring pressure and the valve job.
Most people run steel rocker gear and I'm wondering if the aluminum t&d is flexing under load and getting unstable.
The higher spring pressure almost seems like it made things worse.

Thanks for any ideas
 

·
Registered
Joined
·
1,219 Posts
On a TAD engine we saw much better traces on the spintron with a steel scrubber rocker than even a steel roller rocker. We could only attribute that to rocker arm flex. I would venture to say, yes the aluminum rockers are hurting you.
 

·
Registered
Joined
·
1,570 Posts
Discussion Starter #3
On a TAD engine we saw much better traces on the spintron with a steel scrubber rocker than even a steel roller rocker. We could only attribute that to rocker arm flex. I would venture to say, yes the aluminum rockers are hurting you.
If you were in my shoes would you back down on pressure a little?
We keep trying more pressure thinking it will stabilize but maybe its the wrong direction.
The previous owner of the engine ran used prostock springs and just changed them all the time.
Maybe he was smart?
 

·
Registered
Joined
·
1,219 Posts
I would look at the rockers first.
 

·
Registered
Joined
·
1,570 Posts
Discussion Starter #5
I would look at the rockers first.
I understand. The rocker system holds us back on several fronts but we need to make two more races and then we'll regroup over the winter.
My current springs can produce 450lbs right at the min. installed height.
Our next race is a soft track so hopefully they wont see huge rpm.


We see losses on both intake and exhaust equally even with 60 psi and a 30g heavier intake valve.
That tells me seat pressure is not really the key to this problem.

I have tons of money in spares and tools to support my current rockers. If I can find any way to make them livable I will give up some performance.
 

·
Registered
Joined
·
1,219 Posts
What spring, what installed height and exactly how much lift. If this is private stuff send me a PM or call 866-799-9417 x5
 

·
Registered
Joined
·
1,570 Posts
Discussion Starter #7
Left you a voicemail Matt

.500 lobe lift with 1.7 rocker .024 lash
Spring is Pac TVS 2078
[email protected]
CB 1.14
902 rate
batch 44597

I install at 2.1 and then shim as they fall off.

Thanks
Mike Bruns 3162593883
 
1 - 7 of 7 Posts
Top