Injector hold down bolts stretch?

thunder550

Active member
Apr 2, 2013
1,176
16
38
Phoenix, AZ
When I get into higher boost levels I start to get ticking coming from one of the cylinders. I'm 99.9% sure it's air getting past the copper injector seats. I tightened them a bit and now it takes more pressure to make the sound, but still does it. Do the factory bolts stretch? What can I do to get more seat pressure on the injectors to help them seal better?
 

03_DMAX

New member
Aug 15, 2010
124
0
0
Studs/Billet hold downs are not needed at your power level. Get new oem factory bolts and torque to spec. Problem solved....
 

bml2200

Member
Oct 16, 2008
256
0
16
IL
Make sure there isn't a copper washer stuck in the bore as well. I've snapped a hold down bolt while torquing before, it sucks.
 

Hot COCOAL

May the farce be with you
Jun 9, 2012
4,433
0
0
I re-torqued then 2x and was fine and like others cleaned the threads and lubed them upon installation

The 3rd time was the "stretch point" for me, I wound up torquing them way past the factory spec to get them to seal under boosted cylinder pressure...

New ones will serve you well, no need for the SoCal hold downs...
But they are cool
:thumb:
 

thunder550

Active member
Apr 2, 2013
1,176
16
38
Phoenix, AZ
Everything was really clean, heads had just come back from the machine shop and looked brand new. I cleaned the crap out of the valve covers too before reassembling. I think the new bolts will help :)
 

RPM Motorsports

smokinum
May 13, 2008
3,271
10
38
Central Valley Ca.
Make sure the injector hold down pad is in the valve cover, I've seen that a few times. We used stock bolts at 85psi boost all last season without issue. This season we lifted an injector and killed a head (more boost), luckily stock heads are cheap and easy to find:spit:.
 

DMAX497

New member
Sep 27, 2012
398
0
0
Utah
Blew one of mine out this year... Tick way loud and fuel spitting out. The bolt stretched... So hell with it and have billett hold downs now.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,065
4,736
113
Phoenix Az
make sure its not a boost leak or drive pressure leak first. it could be your drive pressure gauge your hearing (if its leaking)