IAG Performance EJ25 User manual

IAG Performance | 1203 Baltimore Blvd. Westminster, MD 21157 | Ph: 410-840-3555 | www.iagperformance.com
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IAG Performance EJ25 Closed Deck Install Guide [v.13.1]
Please Note* This document is intended for IAG Short Blocks that shipped between 4-11-2018 to 4-19-2018. If your block shipped prior to these dates or after
these dates different torque specs are required and there are supporting documents available with those specs.
•Shipped Prior to 4-11-2018 use Closed Deck Document 30TUv.13U30T
•Shipped between 4-11-2018 to 4-19-2018 use Closed Deck Document 30TUv.13.1U30T
•Shipped after 4-19-2018 use Closed Deck Document 30TUv.14U30T
1.
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Case Bolts
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- The case bolt flange diameter should be
.745”. If the case bolt flange diameter is larger, the flange
will need to be ground down to spec. Be careful not to
damage the closed deck plug threads when
installing/torqueing the case bolts.
2.
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Plug Install
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– Each plug has a location identifier
machined into it that corresponds to the deck surface.
Please make sure to install the plug into the correct deck
hole. Example (L1 plug installs in L1 deck location). Each
plug is pre-lubed with a moly lubricant. This should be
adequate to reinstall unless the plug holes or plugs were
cleaned and lube has been removed. The plugs will start
and install by hand, requiring no effort until seating in the
block. *IF UANYURESISTANCE IS FELT - ** STOP **
If you experience resistance, back out the insert and
inspect the threads on both parts; clean the threads as
needed. Reapply the moly lube and try installing it again.
The Plug should sit nearly flush with the deck surface.
Using a torque wrench tighten the plugs until the indicator
line is collinear (lines up) to the line on the block deck
surface. This should require approximately 8-10 lb⋅ft of
torque (no greater than 11) and the plug should be even
with the decked surface.
Acceptable Lubricants:
-ARP Moly Lube
-Loctite LB8012 Moly Paste

IAG Performance | 1203 Baltimore Blvd. Westminster, MD 21157 | Ph: 410-840-3555 | www.iagperformance.com
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-Jet-Lube MP-50 Moly Paste
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If you have purchased the IAG ½” head stud option
proceed to Page 2.
UIf you have purchase the IAG 14mm head stud option
proceed to Page 4.
½” Head Studs Install
1.
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½” Head Studs
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- Using 30w engine oil, lubricate the
studs block end threads and let it sit to drain excess. Do
not drop the stud in the hole as it will damage the leading
thread in the block. The stud will easily start when
engaged in the correct starting thread. It may require
rotating the stud counter-clockwise to feel. The incorrect
starting thread may allow up to one turn of engagement
and get tight. *IF UANYURESISTANCE IS FELT - ** STOP **
If you experience resistance, back out the stud and
inspect the threads on both parts; clean the threads as
needed. Try threading it again.
Studs must be installed with hand tools due to the amount
of thread engagement, friction and lubrication. Do not
attempt to fully install and seat each stud in one sequence.
Move stud-to-stud until fully seated.
2. Verify stud height relative to each other stud. The
exposed stud to deck height should be 3.760”-3.800” (All
studs should be within +/- .008” of each other).

IAG Performance | 1203 Baltimore Blvd. Westminster, MD 21157 | Ph: 410-840-3555 | www.iagperformance.com
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3. Apply ARP lube to the studs top five or more head side
threads (completely around the circumference, not just a
dab one side) as well as both sides of the flat washer and
the flange of the nut. Install the cylinder head, washers
and nuts.
½” Head Stud Torque Specs
Center Two
Outer Four
Step 1
30 lb⋅ft
30 lb⋅ft
Step 2
70 lb⋅ft
70 lb⋅ft
Step 3
110 lb⋅ft
110 lb⋅ft
Step 4
125 lb⋅ft
125 lb⋅ft
Repeat Step 4

IAG Performance | 1203 Baltimore Blvd. Westminster, MD 21157 | Ph: 410-840-3555 | www.iagperformance.com
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Preparing cylinder heads for ½” head studs
The larger ½” head studs (threads measure .496”) require
drilling out the cylinder heads for clearance. Use a 33/64
or .515” bit to drill out the head stud locations on the
cylinder head. Make sure the heads are sorted and free of
debris before installing onto the short block.
14mm Head Studs Install
1.
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14mm Head Studs
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- Using 30w engine oil, lubricate the
studs block end threads and let it sit to drain excess. Do
not drop the stud in the hole as it will damage the leading
thread in the block.

IAG Performance | 1203 Baltimore Blvd. Westminster, MD 21157 | Ph: 410-840-3555 | www.iagperformance.com
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2. In order to tighten the studs to the block it will require
using hand tools and two head stud nuts. Thread the two
nuts to the cylinder head side as shown in the picture. (Nut
flanges against one another)
3. Slide a 18mm 12pt open end wrench down the stud and
then hand thread the stud into the block.
*Note: the wrench is used to tighten the two nuts against
one another and to break the nuts free once the stud is
torqued in place.
*IF UANYURESISTANCE IS FELT - ** STOP **
If you experience resistance, back out the stud and
inspect the threads on both parts; clean the threads as
needed. Try threading it again.
Studs must be installed with hand tools due to the amount
of thread engagement, friction and lubrication.
4. Torque the stud to 10lb/ft. Once torqued, loosen the
nuts and proceed to the next stud location repeating this
step.
Do not attempt to fully install and seat each stud in one
sequence. Move stud-to-stud until fully seated.

IAG Performance | 1203 Baltimore Blvd. Westminster, MD 21157 | Ph: 410-840-3555 | www.iagperformance.com
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5. Verify stud height relative to each other stud. The
exposed stud to head gasket surface height should be
4.035”-4.055” (All studs should be within +/- .008” of each
other).
6. Apply ARP lube to the studs top five or more head side
threads (completely around the circumference, not just a
dab one side) as well as both sides of the flat washer and
the flange of the nut. Install the cylinder head, washers
and nuts.
14mm Head Stud Torque Specs for IAG Short Blocks that shipped between 4-11-2018 to 4-19-2018.
*If your block shipped prior to these dates or after these dates different torque specs are required and there are supporting documents available with those specs.
http://www.iagperformance.com/support-a/265.htm
Center Two
Outer Four
Step 1
40 lb⋅ft
30 lb⋅ft
Step 2
87 lb⋅ft
70 lb⋅ft
Step 3
115 lb⋅ft
110 lb⋅ft
Step 4
130 lb⋅ft
120 lb⋅ft
Step 5
130 lb⋅ft
130 lb⋅ft
Repeat Step 5
Preparing cylinder heads for 14mm head studs
The larger 14mm head studs (threads measure .563”)
require drilling out the cylinder heads for clearance. Use a
37/64 or .578” bit to drill out the head stud locations on

IAG Performance | 1203 Baltimore Blvd. Westminster, MD 21157 | Ph: 410-840-3555 | www.iagperformance.com
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the cylinder head. Make sure the heads are sorted and
free of debris before installing onto the short block.
Preparing head gaskets for 14mm head studs
1. The center two head stud locations on the head gaskets
require drilling out to clear the larger 14mm hardware. The
best way to accomplish this is to utilize a piece of
aluminum or nice flat piece of wood. Create a pilot hole in
the substrate using a drill and step bit maxing out the hole
to 9/16”.
2. Place the head gasket on the clean flat substrate lining
up each of the (x2) center head stud holes to the pilot hole
you created. *Make sure not to dent or bend the head
gasket to avoid damage and improper sealing. Using the
step bit, drill out the (x2) center head stud locations on the
gasket to 9/16”. *We have found the best way to drill the
gasket is to start drilling one side, then flip the gasket
over and drill the other side and continue alternating to
avoid burrs and snags.
3. Once completed make sure to clean the gasket so it is
free of debris.