Spacing Ign Coil off of head.
#1
Safety Car
Thread Starter
Member Since: Dec 2007
Location: Sandhills of North Carolina
Posts: 3,616
Likes: 0
Received 5 Likes
on
4 Posts
Spacing Ign Coil off of head.
For a LT1
I've read about doing this but never have tried it. Any of you?
The reason I want to do it is that the threads for the bolts that hold the ICM on the heat sink are striped out. If I can space the coil off of the head with some washers I can get bolts with nuts of them and fix this mess. I guess what I need to know is will it hurt anything to do this?
Thoughts, opinions.......
I've read about doing this but never have tried it. Any of you?
The reason I want to do it is that the threads for the bolts that hold the ICM on the heat sink are striped out. If I can space the coil off of the head with some washers I can get bolts with nuts of them and fix this mess. I guess what I need to know is will it hurt anything to do this?
Thoughts, opinions.......
#3
Le Mans Master
Been away from the computer for a few days.
Find several washers that fit on the stud that holds the power steering resevoir.
I used 6 total
Un bolt the power steering resevoir bracket
un bolt the ICM/Coil assembly
reinstall the ICM/Coil assembly using 3 washers between the assembly and the head on both bolts. It will give you about 1/4 inch air gap.
Find several washers that fit on the stud that holds the power steering resevoir.
I used 6 total
Un bolt the power steering resevoir bracket
un bolt the ICM/Coil assembly
reinstall the ICM/Coil assembly using 3 washers between the assembly and the head on both bolts. It will give you about 1/4 inch air gap.
#4
Safety Car
Thread Starter
Member Since: Dec 2007
Location: Sandhills of North Carolina
Posts: 3,616
Likes: 0
Received 5 Likes
on
4 Posts
Been away from the computer for a few days.
Find several washers that fit on the stud that holds the power steering reservoir.
I used 6 total
Un bolt the power steering reservoir bracket
un bolt the ICM/Coil assembly
reinstall the ICM/Coil assembly using 3 washers between the assembly and the head on both bolts. It will give you about 1/4 inch air gap.
Find several washers that fit on the stud that holds the power steering reservoir.
I used 6 total
Un bolt the power steering reservoir bracket
un bolt the ICM/Coil assembly
reinstall the ICM/Coil assembly using 3 washers between the assembly and the head on both bolts. It will give you about 1/4 inch air gap.
On another note I was able to drive the car just a little before it threw a PO1351 code because of the loose screws on the ICM. All I can say is WOW! The AFR's really woke this thing up, BIG TIME! Can't wait to get it to the dyno and track this weekend!
#5
Like jaa1992 said, all it takes is a few washers. I did it when I had an issue with the motor skipping once hot. The ICM was getting heat soaked and failing. It worked and solved the skipping, though temporary. Eventually the ICM bit the bullet and I replaced. I don't see any downside to spacing it off the cylinderhead.
#6
Safety Car
Thread Starter
Member Since: Dec 2007
Location: Sandhills of North Carolina
Posts: 3,616
Likes: 0
Received 5 Likes
on
4 Posts
Like jaa1992 said, all it takes is a few washers. I did it when I had an issue with the motor skipping once hot. The ICM was getting heat soaked and failing. It worked and solved the skipping, though temporary. Eventually the ICM bit the bullet and I replaced. I don't see any downside to spacing it off the cylinderhead.
Got everything I need and this afternoon I'll put it back together. I went to Radio Shack and got some Heat Sink compound. If you go to the auto parts stores they'll give you dielectric grease which is not the correct thing to use. I read a lot about ICM's failing. Using the incorrect lube behind the ICM might be one reason why.
#7
Le Mans Master
Got everything I need and this afternoon I'll put it back together. I went to Radio Shack and got some Heat Sink compound. If you go to the auto parts stores they'll give you dielectric grease which is not the correct thing to use. I read a lot about ICM's failing. Using the incorrect lube behind the ICM might be one reason why.
I did not know that heat sink compound was different than dielectric grease. My car was missing at cruise in once hot, so I just regreased it over the weekend, it looks like I will be doing it again this weekend, good thing it is an easy job. The FSM only called it silicone grease.
#8
Melting Slicks
Got everything I need and this afternoon I'll put it back together. I went to Radio Shack and got some Heat Sink compound. If you go to the auto parts stores they'll give you dielectric grease which is not the correct thing to use. I read a lot about ICM's failing. Using the incorrect lube behind the ICM might be one reason why.
Dielectric grease is a non-conductive, silicone grease designed to seal out moisture and, therefore, prevent corrosion on electrical connectors. Being non-conductive, it does not enhance the flow of electrical current. This property makes it an ideal lubricant and sealant for the rubber portions of electrical connectors.
]
Thermal grease (also called thermal gel, thermal compound, thermal paste, heat paste, heat sink paste, heat transfer compound, or heat sink compound) is a fluid substance, originally with properties akin to grease, which increases the thermal conductivity of a thermal interface by compensating for the irregular surfaces of the components. In electronics, it is often used to aid a component's thermal dissipation via a heat sink.
Eddie
Last edited by MK 82; 06-09-2010 at 03:16 PM.
#9
Race Director
I spaced my ICM with a few washers that last time I had the heads off, didn't notice a difference. Still running the original ICM, never used the heat sink grease, and it is still running strong (knock on wood).
#11
Safety Car
Thread Starter
Member Since: Dec 2007
Location: Sandhills of North Carolina
Posts: 3,616
Likes: 0
Received 5 Likes
on
4 Posts
Here's what you need to get. It's about 12.00 an oz. but this little tube only cost 3.00 and change. It's size is .23 oz. Probably enough to do 4-5 ICM's.
The finished results
The finished results
Last edited by Weav's Vet; 06-09-2010 at 07:20 PM.
#12
Instructor
Nice work. I often wondered why GM did not use offset washers for the ICM heatsink, and decided to mount it directly to a HOT cylindar head....dumb...dumb...dumb. I did this "mod" on my '95. I need to get around and do it on my '94 .
#14
Tech Contributor
Member Since: Jun 2004
Location: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Posts: 18,480
Received 783 Likes
on
560 Posts
Spacing the ICM away from the head looks good, but in worst case driving conditions the lengthened thermal transfer path isn't desirable.
#15
Tech Contributor
Member Since: Jun 2004
Location: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Posts: 18,480
Received 783 Likes
on
560 Posts
For the same reason that GM/Delco didn't put rubber washers under the HEI modules in their old distributors. These ignition modules' internal electronics aren't fragile printed circuit board construction, so they don't need the rubber washer bandaids.