Build Thread Want To Blow 5 Years And $50k On A Foxbody? Step By Step Instructions Inside!

  • Sponsors (?)


The leak down tests are in, and they're not very good. I got the engine up to temp, pulled the plugs, got the cylinder I was testing up to TDC, and then hooked up my OTC leak down tester. Pressurized each cylinder to 80 psi and got the below leak percentages.

Cyl 1 - 19%
Cyl 2 - 19%
Cyl 3 - 25%
Cyl 4 - 25%
Cyl 5 - 15%
Cyl 6 - 13%
Cyl 7 - 29%
Cyl 8 - 30%

All the numbers are pretty bad for a new engine. Maybe cylinders 5 and 6 could pass as okay, but the rest are just not good. A new engine is apparently supposed to be below 10%. All the leaking was from the crankcase. Intake and exhaust were quiet, and the coolant was stagnant. I'm actually glad the results are bad. Confirms the source of the smoke on decel. Time to get that 331 out and off to the doctor.
 
I need to hire @84Ttop so I can have the engine out of the car in 20 minutes ;)
Saw the front end off?

Kidding of course. A ball hone and a new set of rings should take care of the problem, the disassembling the entire engine to hone and wash the block correctly is the part that sucks. You attempting this yourself Scott or having your machine shop do the tear down?
 
I'm probably going to wind up just delivering the shortblock to Gil Davis and having the shop take care of everything. Shortblock engine work is one thing I believe is best left to those that work on engines for a living. If I drop that crank or mess something up, I'll be so pissed at myself.
 
  • Like
Reactions: 1 users
All ready to come out. I need to haul my engine hoist up from the basement, so that can wait until tomorrow.

737e03aec5cae31fd4d3b3358adfb75a.jpg


While the engine is out, I'm going to use that opportunity to wrap the rest of the hotside. I'm also going to eliminate some of the polished parts in the engine bay. I have grown very fond of wrinkle black engine parts, so I may spray those polished parts with that paint. We shall see.
 
  • Like
Reactions: 1 user
And she's out.
DSC_3129_zps330d6dd9.jpg

One thing I was curious about what how well the headers were sealed to the heads. The Earl's graphite gaskets I have are awesome. Not a single leak at the heads. I definitely recommend these things.
DSC_3130_zpsa7219f6c.jpg

DSC_3131_zps468e4f45.jpg

Got the heads off soon after.
DSC_3135_zpsff990631.jpg

I cleaned up one of the cylinders to inspect the walls. No crosshatch to be seen anywhere. I'm no engine expert, but it's my understanding that the crosshatch should be visible throughout the usable life of the engine. There is also light vertical scoring in the bores.
DSC_3142_zps825c0bf1.jpg

DSC_3145_zps3fbf75d7.jpg
 
Last edited:
No visible cross hatch is definitely lending itself to your wash down and ring seal issues. Gil and Eric (at Davis race engines) are two of the best guys in the business as far as I'm concerned and you will be in very good hands there!
I really like those header gaskets too by the way. You have a part number for them? I would like to use something like that on my brothers 363 that Gil just finished up a few months ago
 
Ouch man. Definitely on the crosshatch. For the sake of comparison, I picked up a 150k-ish miles 351 this weekend from @Boosted92LX and the cross hatch is still visible on the walls.

I know when I yanked out my 110k stock block, there were still crosshatch marks on the walls also. The vertical scoring is also concerning to me. Definitely tells me that oil isn't staying on the cylinder walls. Also, my oil pan plugs have magnets on the ends. When I drained the oil, there was a decent amount of metal "paste" stuck to them. I'm sure it came from the cylinder walls. I have a filter magnet on my oil filter, so I'm going to cut it open and see what that looks like.
 
  • Like
Reactions: 1 users