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Old 09-03-2015, 12:04 PM   #1
jmillsUT28
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Distributor cap hitting firewall on 72 Blazer "Fixes"?

Hey guys I am new here. Just bought a restored 72 Blazer. Trying to work out a few small bugs. One is the distributor. It's hitting the firewall pushing it forward a little to the point it starts ticking. Have to get out push it back towards the firewall about 1/4" then it stops ticking.

This only happens when I put it in reverse and back up a incline. Motor mounts seem to be fine as the engine does not move hardly at all when I put it in drive and reverse when the brake on.

It has the HEI distributor on it right now.

What are my options to fix this? I installed a 3/16" spacer on the trans mounts but still seems to be doing the same thing.

Thanks for the help!
Jon
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Old 09-03-2015, 12:10 PM   #2
cleszkie
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

An HEI distributor will be a tight fit. I had to very slightly modify my firewall to make enough room for movement. Another thought - what shape are your trasfer case mounts in? If they are 40 year old rubber units, they are probably getting flattened out. New rubber or poly mounts will raise the transfer case a little, but more importantly, it will tilt the entire driveline such that the distributor will move away from the firewall.
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Old 09-03-2015, 12:14 PM   #3
jmillsUT28
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

The transfer mounts are old. Look worn out. Think I will try that first as it is cheaper than the $350 option for the distributor.
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Old 09-03-2015, 02:28 PM   #4
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

not sure if its worth all the work but you could put a mid plate between the engine and trans and then spacers between the torque converter and flexplate. pry would allow you to space the motor forward 1/4".

fyi my HEI is very tight too, although i dont have any problems with it.
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Old 09-03-2015, 02:45 PM   #5
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

I would try taking some weight off the engine cradle with an engine crane loosen the bolts to the engine cradle, motor mounts, tranny crossmember, and try and push everything forward may give you a 1/4 inch or enough.
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Old 09-03-2015, 03:09 PM   #6
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

Body lift? Looks like you could use the clearance in the wheel wells anyway.

Pretty blazer.
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Old 09-03-2015, 09:30 PM   #7
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

A big hammer
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Old 09-03-2015, 09:31 PM   #8
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

maybe change your ignition system to a pertronix? It has the stock look with the performance of a HEI system.
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Old 09-04-2015, 12:43 PM   #9
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

Thanks guys, I bought some new mounts online so will try that first. Needed to replace them anyways. If that does not work then will look into the pertronix.
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Old 09-04-2015, 04:12 PM   #10
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

I used an MSD ready to run small cap distributor in my Jimmy. I knew the HEI was going to be an issue and the MSD has been the perfect solution.
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Old 09-04-2015, 05:45 PM   #11
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

5.3 !! no distributor ! LOL
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Old 09-07-2015, 07:02 PM   #12
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

I have an msd e-curve in mine. Has plenty of room.
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Old 09-07-2015, 07:21 PM   #13
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

Could it be worn out body mounts?
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Old 09-10-2015, 08:33 AM   #14
jmillsUT28
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

Well I installed new transfer and trans mounts but did not fix the problem. Thinking I will just give in and install a MSD.
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Old 09-10-2015, 01:03 PM   #15
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

My 72 was giving me a fit with the old points distributor. It came with a 307 and motor mounts are in the rear frame holes. I slid old points setup out and slid the large cap HEI setup right in with no issues. I still have room to get my hand between cap and firewall with no mods.

I wonder if the body has been undone on the Blazer and may be shifted forward on the mounts a touch or the mounts are loose enough to cause enough flex to push on the cap.

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Old 09-10-2015, 04:47 PM   #16
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

I think ya'all are makin this tough. Move the motor mounts to the front set of holes in the frame rail.
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Old 09-10-2015, 10:03 PM   #17
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

Before reading anything anyone else typed I was going to suggest body mounts, looks like you are already working on that.

Quote:
Originally Posted by 4oldcars View Post
I think ya'all are makin this tough. Move the motor mounts to the front set of holes in the frame rail.
He has a 4wd; that would require modification to the front drive shaft for sure, probably the rear drive shaft, 4x4 shifter needs to move in the cab, and the engine oil pan may hit the differential during suspension travel. The oil pan vs front differential is the reason 4x4's use the back mounting holes.
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Old 09-16-2015, 04:57 PM   #18
jmillsUT28
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

Hey guys I tried the mounts but they did not fix the problem so I just replaced the distributor and now have a 1/4" space and it does not hit the firewall. Nice not having to worry about it hitting anymore. Thanks for all of the help!
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Old 09-16-2015, 06:32 PM   #19
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

1/4" is about right. That's what I had on mine. It's definitely a close fit.
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Old 09-19-2015, 06:24 PM   #20
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

Wouldn't moving the engine forward require different driveline lengths? I've seen people move the engine forward to put in a 700r4 and it leaves the transfer case in the same spot.
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Old 09-19-2015, 09:22 PM   #21
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

Use the small cap HEI from the Camaro/Caprice/truck. Normal size cap, external coil.

Just google "small cap HEI"
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Old 09-22-2015, 01:29 PM   #22
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

Accel Point Eliminator Kit #2010, Summitt Racing, $$60.97 15 minute installation. new coil, $#40000011 $33.97
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Old 09-22-2015, 01:43 PM   #23
michael bustamante
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

what about the hei with an external coil? that cap is alot smaller. on the 88-98 engines i think?
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Old 09-22-2015, 04:29 PM   #24
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Re: Distributor cap hitting firewall on 72 Blazer "Fixes"?

Exactly what I said...
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