Looks like the heads may be coming back off :-(

[old truck guy]

Ok my links for the bin files and data logs don't seem to be working. What is the best way to upload these?

[Dr_Grip]

Ok my links for the bin files and data logs don't seem to be working. What is the best way to upload these?

Click "go advanced" in the reply window, scroll down, use the "attach" function. :)

[old truck guy]

[dave w]

I'm trying to understand what happened? Did you have a mechanical failure?

Remote tuning can require several data log / .bin files, because the changes to the .bin are smaller in nature when I'm not actually with the vehicle.

To date, the best performance I've achieved, that was actually dyno'ed, with an engine similar to yours was 330 RWHP. I might have achieved better performance, but most tunes I've done don't go to the dyno. Most tunes I've done are usually budget builds that can limit performance options.

dave w

[Roadknee]

I'm almost certain 17-18 psi with the stock spring has the spring coil bound. If it is the fuel pressure will not be constant as the fuel demand through the injectors changes and the engine will run erratically. IIRC, BLG355 from this forum installed a 1995 K1500 brake cylinder spring inside the stock spring and was able to get over 20 psi. I think you'll need at least 18 with the cop car injectors (68 pph?) to supply your engine. I recommend you fix your mechanical issue, get fuel pressure squared away and give it another whirl. Unless that air leak is really bad, you might try swapping that rocker stud, reassemble and check compression before tearing it completely down.

[brian617]

I'm almost certain 17-18 psi with the stock spring has the spring coil bound. If it is the fuel pressure will not be constant as the fuel demand through the injectors changes and the engine will run erratically.

I second that, I even had and TBI Chips "18psi" spring that coil bound at 17.5psi caused all kinds of problems because the fuel pressure wasn't consistent.

[old truck guy]

I'm almost certain 17-18 psi with the stock spring has the spring coil bound. If it is the fuel pressure will not be constant as the fuel demand through the injectors changes and the engine will run erratically. IIRC, BLG355 from this forum installed a 1995 K1500 brake cylinder spring inside the stock spring and was able to get over 20 psi. I think you'll need at least 18 with the cop car injectors (68 pph?) to supply your engine. I recommend you fix your mechanical issue, get fuel pressure squared away and give it another whirl. Unless that air leak is really bad, you might try swapping that rocker stud, reassemble and check compression before tearing it completely down.

Eaglemark has a thread stating EP377 pump with gold spring good for 16-26 psi. Where do I get it?

[old truck guy]

I'm trying to understand what happened? Did you have a mechanical failure?

dave w

Yes obviously a mechanical failure, and fouled plugs I'm assuming from too much fuel at low rpm's. Will get back with you once back up and running and fuel pressure straightened out.

Thx, Mike

[V8Astro]

I have a comment for the mechanical part only because I've been there done that. I had the exact same thing happen to me once. I can tell by how far down the set screws are in your poly-locks that your rocker studs are too short. I'm willing to bet the little bit of broken rocker stud that was left is only 3-4 threads long. I had one pop just like that 50 miles from home once. It happened at a stop light in my case nothing but the stud and a pushrod were damaged. I ordered a set of +.200" studs. Fixed it right up

[Roadknee]

I have a comment for the mechanical part only because I've been there done that. I had the exact same thing happen to me once. I can tell by how far down the set screws are in your poly-locks that your rocker studs are too short. I'm willing to bet the little bit of broken rocker stud that was left is only 3-4 threads long. I had one pop just like that 50 miles from home once. It happened at a stop light in my case nothing but the stud and a pushrod were damaged. I ordered a set of +.200" studs. Fixed it right up

Good catch! I suppose if the rocker ball is riding on the threads instead of the shank of the stud the stresses during operation can form a crack in the threads and ultimately shear the stud.

[Kitch]

From the photo it looks like you're running standard non self alining roller rockers.
I could be wrong on this but I thought if you had standard tip roller rockers and round pushrod holes in the head then you needed to use guide plates.

[old truck guy]

From the photo it looks like you're running standard non self alining roller rockers.
I could be wrong on this but I thought if you had standard tip roller rockers and round pushrod holes in the head then you needed to use guide plates.

They are the Comp 1417. They are self aligning but it's hard to tell from the photo. Thx though.

[old truck guy]

Good catch! I suppose if the rocker ball is riding on the threads instead of the shank of the stud the stresses during operation can form a crack in the threads and ultimately shear the stud.

Those Mr Gasket studs are only 1.48" installed height. Definitely looks like I'm at least partially on the threads.

[old truck guy]

I have a comment for the mechanical part only because I've been there done that. I had the exact same thing happen to me once. I can tell by how far down the set screws are in your poly-locks that your rocker studs are too short. I'm willing to bet the little bit of broken rocker stud that was left is only 3-4 threads long. I had one pop just like that 50 miles from home once. It happened at a stop light in my case nothing but the stud and a pushrod were damaged. I ordered a set of +.200" studs. Fixed it right up

Agreed! Went with the Mr Gasket 1076 because they didn't require machining of the bosses and I already had the heads back from the machine shop when I decided to go to screw in studs. Got cheap for a moment. Just ordered the ARP 1.75 installed height studs. Gonna pull the heads anyway and do it right.

Good catch and thanks!