Blown BBC intake bolts loose

I have a few intake bolts that keep coming loose every pass. Blowing oil everywhere

Blown Alky BBC, 540", flat tops, 30 degrees, 25lbs of boost, power grid ignition, 16v system, Flatout Racing intake gasket.

What could it be? Detonation? blower out of balance? drive shaft?

We dyno'd the motor with a 7al-3 box, I believe. So, i wouldnt think i am running out of spark, but maybe I am.

Greatly Appreciate any help.

 

Most probable is detonation-

 

Was this assembly balanced-this can cause things to come loose

 

Nord locks or less timing.

 

Every time that has happened to us it was a timing issue. And usually when you start looking around it will be something loose, bad wire.

 

I had that problem when we first started running the blower engine. I bought a tune up and it was REALLY fat!!!. Fuel coming out the pipes during the run Fat. My kept loosening the timing cover bolts. I was running a Mallory III.
Once I got the tune up leaned out it all went away.
So it obviously was a misfire issue.

 

I went through this for years. One set of heads, only way to keep the bolts tight was to fatten up and back timing down and run 6.60. I could go 6.40 but all the intake bolts would be backed out every run. Red loctite, green loctite, threads clean, torqued, retorqued, didn’t matter. Nordlocks fixed it to where I would have to tighten a bolt every few passes. Egts were super high running 6.60s but they would come down as I added timing and pulled fuel away. Bearings were ok. Could run them forever at 6.60 and a dozen or more passes at 6.40. At 6.60 the puke tank would be dry. At 6.40 it would be full.

Eventually got my other set of heads fixed. Almost identical except smaller chamber (113 vs 119). I could go 6.20s and not loosen a bolt. Egts were a little lower. Bearings about the same. Puke tank empty most of the time.


I know it was detonating with the slow heads but I sure couldn’t figure out why so I put them on a bracket car.

 

I was wondering if my msd grid ignition was too weak. I just sent my blower off to have it checked. The timing marks on the plugs look good

 

This motor is making use of the puke tank, about setup in size. I have a quart size tank on it now.

 

https://www.racingjunk.com/Other/184056820/Funny-Car-Altered-Puke-Tank.html

 

Mike will email pics, NGK - 9s with .018 gap.

 

Also these are brand new brodix BB3 380s Hip treated. I bought them new last year. Motor was balanced and assembled (last year) and this year.

 

.018 is bigger than I ever ran with my 7al2. .012 -.015 max

In my experience if it’s putting anything besides water and alky in the puke tank, it’s not completely happy with something.

For awhile before I changed heads I could tell what the plugs were going to look like within about 5 seconds of exiting the car after a pass. If the puke tank breathers were wet and I could see the intake bolts backed out, I would start hoping I still had 8 straps and would start thinking about pulling the pan. At the very least, I knew I needed to fatten it back up for the next pass. Usually a three thread tuneup but it was the only way I could get those old heads to run a decent number.

Is this combo putting up good numbers?

 

I am happy with the power, made 1660 on the dyno and was climbing, I run it though at about 7500. EGTs all about 1050s. My logger says they are in the 1250s 1300s. None of the plugs are melted. I thinks its the location of my egts, bottom of the zoomies. I had the blower checked out at Littlefield and they said nothing was out of balance and all was good. I am going to get my driveshaft re-balanced this week just to make sure. I am just baffled. My next tune up will be with 5* less timing and I will add a little to the main jet. We will be in San Angelo, TX with crummy air.

 

I was always unsure of chicken vs. egg. Did the bolts come loose and that let boost into the crankcase, causing it to push oil and detonate, or did it detonate first, start pushing oil, and that loosened the bolts.

When I put the nordlocks on, I determined it was probably a little of both but either way those little things are awesome.

Also at some point I put steel threadserts in the heads and felt like that helped too.

 

14mm belt? How are the bearings in the idler and drive?

 

8mm, Idler bearing feels good to me, snout was inspected at Littlefield and was good, they did put new seals etc in the snout.