Rebuilding the bottom end of a big block
 

I haven't built engines in at least 15 years. I built big and small blocks. Everyday drivers as well as hot rods. SDBA drag boats and a few 1/4 mile drag cars. I know the new boats have all the new electronics and you have to know your way around the computer but what about the bottom end???

Every engine up to date I have seen laying around so far apart still seem to have the same internals they did years ago. I'm sure they might have switched to full floating instead of pressed rods or some other small idio syncracies.

I got out of rebulding my stuff when I started making what I think is good money, but now I have the itch to take a shot at rebuilding the bottom end of my 502mpi gen6 motor. Is it more involved than it was years ago or do I leave it to the pro's?? I have a shop at my house, just need to buy a few specialty tools, torque wrench, ring compressor, plasti gauge for checking clearances. Maybe check some end gap clearances also.

Lets say the engine just needs to be freshened up, no major block work etc,,,,

How bout some input from you everyday joe's as well as some engine builders. Just want an open objective opinion with a little honesty thrown in. :D :D


Thanks,
Shawn

Re: Rebuilding the bottom end of a big block
 

From what I have seen, there are better bolts/studs gaskets and rings. Tolerances can be closer. But otherwise nothing much has changed over the past 20 years.

I am sure you have seen the oil bypass releif valve issue on gen 5/6 marine motors which seems to be the main issue.

Re: Rebuilding the bottom end of a big block
 

Wanna enlighten me a lil' on the bypass relief. Like I said it has been a while. Didn't know thier was issues on them.

Thanks

Re: Rebuilding the bottom end of a big block
 

Here is one thread of many.
http://www.offshoreonly.com/forums/s...29#post1367029

Main thing is that cooking block will ruin valve which should be out and replaced anyway, must be 30psi marine one. Some plug one hole and run 1 30psi valve, some plug both holes. I can't say which is the right way to go.

Gen 4 blocks had external releif so it wasn't an issue. It was in the filter pad adapter. On my gen 4 I plugged the external releif valve and let the mobil-1 filter do the work.

Re: Rebuilding the bottom end of a big block
 

Thanks bro... I was wondering about that one. All this info is sure making my mind up quick :eek: :D

Re: Rebuilding the bottom end of a big block
 

Just noticed "Houston, TX" . You a Clear Lake Boater? I run the San Jacinto on down to Galveston mostly.

Re: Rebuilding the bottom end of a big block
 

Yeah, I live in Pearland but,I usually put in at Kemah bridge and run to the river and hang out all day or Galveston for lunch. If nothing else chill in Taylor Lake. :D

Re: Rebuilding the bottom end of a big block
 

Keep an eye out for me. I'd like to check out that whipple install.

Re: Rebuilding the bottom end of a big block
 

29Scarab,

One thing you mentioned that's changed is that plasti-guage isn't used by anyone doing anything more the most-econo rebuild, if that.

If I saw a shop using it, I'd definitely be going elsewhere, it's just not accurate enough. You can get an inner and outer micrometer set inexpensively enough to justify the cost if your using new parts and want to check it yourself. If you're having a machine shop blueprint/recondition your used parts, they'll polish your crank, resize rods, and align hone the blcok if necessary and they should be setting all the clearances as they should be (although it is nice to double check their work).