Quote:
Originally Posted by twoTSis
Most of those tips are obvious, but how about when I go to the machine shop here in the next week. What all should I ask to have done?
|
I guess the answer to that question depends on how paranoid you are about engine durability and crankwalk. I have not heard of many 2.4 7bolts (4G64 blocks) that have crankwalked and I'm sure CW is even more rare for 6bolt 2.4 (G4CS blocks), but if your already investing a large chunk of money rebuilding an engine you might as well make it as bulletproof as possible. One of the best theories for the source of crankwalk in DSM's was that the iron content in Mitsu engine blocks found in 1995+ models was less than in previous years and could cause the mains to shift, allowing excessive crank play which eventually leads to crank walk. This is one reason some people opt for a 6bolt 4g63 or a G4CS. When I upgraded to my 2.4 I already had a good 4g64 block and crank so In order to ensure my engine would not crankwalk I had the machine shop dowel pin the main girdle and align hone the mains. My machinist also assembled the block with a custom torque plate which simulates the presence of the head on the block and ensures that everything is aligned perfectly. All of this is probably overkill, but like I stated before, better to do it right the first time than to spend more money fixing problems later. The oil squirters were also considered to be a possible crankwalk culprit, but the 4G64 does not have oil squirters so you won't need to bother having them removed if your using a 7bolt. You might as well go ahead and eliminate the balance shafts while the engine is apart and have the machinist balance and blueprint everything. You may also want to go ahead and have the cylinder walls bored .20 or .40 over if you haven't purchased pistons yet. In my humble opinion, you should get the largest bore possible and at least 9:1 compression. Your blog said something about BC custom pistons and econorods.. I'm not sure how comfortable I would feel building a motor with connecting rods nicknamed "econorods" but then again, I'm sure BC knows what he's doing. I personally use a crower/wiseco 9:1 combo and it's been very durable so far. The use of Clevite 77 bearings as well as ARP rod bolts, main studs, and head studs is also highly recommended. If it's a used block you probably want to have it hot tanked and shave the deck so that your head gasket seals perfectly as well. If you have the extra cash to spare and if the machine shop is already going to be doing any work on the head, you might also want to go ahead and invest in a 3 or 5 angle valve job as well as some port work.