Big Block vs Small Block maintenance

[keezling]

Try a California '67 Mustang with thermactor tubes. Undo motor mounts, jack one side of engine up at a time.

[olddog]

Keith Craft once explained that the FE engines were designed for rope seal on the back of the crankshaft. As such, there was no need for precision machining back in the day, but today's seals require the gland to be more centered than what the factor did. Hence the FE reputation for marking its territory. So yes a factory block FE is more likely to drip some oil out the rear main seal. And let's skip talking about the nails in the seal between the rear main cap and the block.

If I recall correctly Keith said he had tried and gave much thought to the problem and even he could not achieve 100% leak free FE engines. I have heard others state if anyone tells you they can, stay away from them cause they are either an idiot or a lyre.

Now if you us a modern new block, I would expect the rear seal issue have improve dramatically, but I have no personal experience.

The FE is a very complicated design compared to a SB. When assemble by a knowledgeable experienced FE builder, it is a great engine. When assembled by other builders with little FE experience, your asking for trouble. That can be said to be true for any engine, but the less complicated the design the better chances are any builder can do it.

So the answer, in my opinion, depends on who is building what.

[wkooiman]

I had a 428 in a 67 Mustang. It didn't leak, and it wasn't difficult to change plugs. You just have to use the proper extensions and universal joints.

It did not have thermactor, and it didn't have the shock tower reinforcements either. It was originally a 289 car.

I currently have a 428 in a Contemporary Classics Cobra. Spark plug changes are simple, but this one does leak a bit. It is an older build, completed in the early 90's. I am piecing together a 427/482. When it is finished, it will not leak.

Your kit might be harder to change plugs.

FEs cost quite a bit more, and it's harder to get parts too, but in my opinion it's worth it.

The #1 question I get with my car is, "Is it real?", followed by, "Does it have a side oiler?" When I open the hood, they go, "Wow!". You don't get that with a 351W.

Power wise, it depends on how they're built. You can built a 351W in the 427" range pretty easily, and it will make more than enough power.

But it will never look like a 427 FE with 2x4s and S&H air cleaners.

[redmt]

Originally Posted by olddog

If I recall correctly Keith said he had tried and gave much thought to the problem and even he could not achieve 100% leak free FE engines. I have heard others state if anyone tells you they can, stay away from them cause they are either an idiot or a lyre.

Idiot or a liar? Really? I guess only a fool would believe that. Either that or it's just somebody looking for an argument.

[patrickt]

Originally Posted by redmt

Idiot or a liar? Really? I guess only a fool would believe that. Either that or it's just somebody looking for an argument.

No, you just redefine "No Leaks" to mean something different. Ford actually did that in the 1960's when it instructed its dealerships to treat small drips from the FE as "commercially acceptable." Personally, I define "bone dry" as three dime-sized drops or less, dropped within a 24 hour period, after a hard run.

[redmt]

Originally Posted by patrickt

No, you just redefine "No Leaks" to mean something different. Ford actually did that in the 1960's when it instructed its dealerships to treat small drips from the FE as "commercially acceptable." Personally, I define "bone dry" as three dime-sized drops or less, dropped within a 24 hour period, after a hard run.

Yep you could look at it that way. I have a couple 8-71 Detroits and in them I define no leaks as anything that doesn't actually drip. They emit oil seemingly through solid castings at times. In this case on FE engines I have had a couple leak. Lets call a leak anything that is visible and not necessarily a drip. Back to OD's original statement of %100 leak free. If you qualify the %100 to be of all FE engine ever built, he would be correct. If you say that any FE cannot be made leak free then that is a false statement. Any FE engine that is properly machined and assembled does not leak.