SBF Firewall Clearance
 

Hi Guys,

Newbie to the forum, here. I'm in the middle of a 302 swap using Martin's kit and I have a question about firewall clearance on the driver's side.

I massaged the firewall 1/4" as recommended in the manual but it still doesn't look like enough room to fit the bellhousing in there. The engine is slid forward all of the way which gives me 3/4" between it and the firewall. (I'm not using an air tube) Still, the boss on the bellhousing is 1 1/4" thick. Do I need to pull the engine and beat that corner where the firewall and tunnel meet? Should I cut down the tab on the bellhousing? Your suggestions are appreciated.

Thanks!

There are a few tight spots around the bellhousing that are not covered in the manual. The first is that one bellhousing bolt. I think it's the second highest on the driver's side. Mark where it almost contacts and smack the tunnel there with a hammer a few times (if the engine is in you can get at the spot with the bell and flywheel off). The second is the other side where the top of the starter "blister" is positioned. You may have to add some room there as well. Again, it can be accessed with the bell off.

Room behind Driver's side head:

If you are using the AIR injection tube this spot is tight. You must use Martin's counter sunk bolt and use a drill to create clearance in the tube boss so that it can be counter sunk. I've also taken a grinder to the top of the boss and ground it down about 1/8 inch to gain more clearance. That portion of the firewall should also be hammered back about 1/4 inch from stock. With the AIR tube there should be a good 1/2 inch of space (about enough to squeeze your finger in) between it and the firewall. If the tube is being left off you automatically gain a full inch of clearance. This allows you to position the engine back another inch (makes changing the belts and servicing the crank pulley much easier) if you make the same modifications to the firewall.

Another point of possible contact is the bottom of the oil pan to the rack. I make sure that there is about enough clearance to easily slide two credit cards stacked between the rack and the pan.

Check all these points WHEN THE TRANS IS BOLTED TO THE TRANS BRACE, not when the engine is only sitting on its mounts.

If any of these possible points of contact are not given enough clearance the driveline may contact during acceleration, deceleration or both and cause a very annoying NVH issue. I know from experience.

Good Luck, let me know if I can help with anything (see my site).
-Jason McCully

NeeD! More PictuRes!

This page links to my Cardomain site with lots of pictures:
http://www.mccullyracingmotors.com/i...les/builds.htm

Enjoy!

-Jason

Sbf Gremlin is back
 

Jason, This weekend my no spark glemlin left me stranded for a short while. I am still loosing spark. 98% of the time it seems to happen when hot. As you know I have change the distributor and also tfi and added the heat sink relocation kit. When I had it in the driveway it lost spark and I quickly put another tfi in and still no spark. If I wait 15 minutes it comes back. My next step is to throw a coil into it. I have checked the coil and all is within the specs listed for it. I am pulling my hair out and by my pictures I dont have much left... anyother suggestions on where to go from here if the coil does not help? Or if anyone else has any ideas...Hey we wanted topics to talk about ... Only have 200 miles of pure enjoyment before my gremlin returned.

You say the coil is within spec. Have you tested the coil itself for spark during one of your no-spark moments? When doing this test, I remove the coil's wire from the distributor, insert a #2 Phillips into the end, set the screwdriver such that its shaft is very near a sharp-edged ground, then crank the engine momentarily and look for spark to jump from the screwdriver shaft to the ground.

I mention this because my first Omni GLH Turbo had a problem similar to yours. The car would cold start just fine, and I could drive it for maybe 10 minutes until it would conk out. At that point, there would be no spark until the car sat for a while to cool off... then the scenario would repeat. In my case, it turned out the coil had a hairline crack in it. Everything worked fine when first started, but as the coil gradually warmed from use its body would begin to warm as well. Eventually, the heat allowed the coil body to expand and the crack would open ever so slightly, allowing internal fluid to weep out. Once the fluid reached the coil bracket, the coil would ground out against the chassis and--presto!--no more spark.

Maybe you're experiencing something similar?

I may be making too much out of my perceived clearance problem. After reading Danny's post about having to dimple the firewall, I have to admit that my 302 isn't as close as what Danny described.

I guess what I was after was just making sure that other 302 installations were a bit tight in that area, and that I wasn't way off the mark with my installation

Did you replace the stator (pick-up coil) in the distributor?

Yes, I have replaced the complete distributor and coil and added the tfi relocation kit. The tfi does not appear to be overheating as i have change the tfi within seconds of loosing spark and the new one does not make any difference. Still loosing spark. What about the ecu causing this?

I have already replaced the coil but can see how it can cause a problem..

found cause
 

Okay, I have located my problem with intermitant spark loss. To refresh my ford 5.0 was dropping spark when it got hot. After doing all the logical or dumb things and throwing parts at the problem the spark still was intermitantly dropping out usually when it got hot. What I found was the harness that goes to the tfi was making and breaking. I was not able to find the exact wire or cause but when it was twisted and pushed on spark would drop out. Talking with Jason we decided to change it out. Got one from a my 5.0 grave yard and spliced it in. Not really tricky but dealing with the foil wrapping and case ground to ensure a good splice was important. So far it started and ran for one hour without droping spark in the driveway. Didnt want to take it out last night and get stranded in the dark. Will drive it a bunch this weekend and see if my gremlin has been terminated.

Very awesome (knock on wood with fingers crossed). I hope you finally managed to iron it out. I would still look at upgrading your mass air tube at some point to a diameter larger than the throttle you have. I’m sure that’s going to cause the computer some confusion at some point.

BTW Gerry, I sent the owner's/source vehicle interchange manual from my last build out to you last night via email. Let me know if you get it. It's pretty big.

-Jason

Jason, was able to download and print...Thank you as it appears to be very helpful. I am going to upgrade my mass air tube.... I got your info about the Thunderbird type from a 1996...Planned upgrade in the near future...