• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Crankshaft machining question

goldgp

goldgp

Grocery Getter x2
I have my GTP's bottom end in the machine shop, and my rod journals will have to be turned 20 thousandths due to my number 1 and 2 cylinders spinning rod bearings.I have heard the cranks have an issue being turned down,any truth to that?

Basically, should i buy a new crank,or will my original be fine to get turned.
Mods will be new federal mogul speed pro pistons (factory compression) ,L32 rods,ARP main and rod bolts (both mains and rods will be machined for those bolts),balanced rotating assembly, XP cam,3.2-3.0 pully gen 3 and supporting stuff.

Any advice would be greatly appreciated,thnx.
 


beware "new" cranks...many are welded and reground cranks that will break, seen it twice right at the journal shoulder....

you will want a good used crank with minimal scoring...

also have em check the oil pump recess in the front timing cover...since it ate itself id bet the aluminum cover is ****ed and even a new pump scroll and cover wont bring clearance into spec...so you need a good cover too...

basically you need to buy a good motor before ever rebuilding a 3800 lol

Moradparts.com is one of your best bets...i only have two minty used cranks and im saving em lol
 
Thanks for the info on the oilpump.Heres another question,Im going to get an oil pressure sender so i can actually tell whats going on pressure wise, what would a normal L67 run pressure wise?
 
just beware that not many people have great luck with rebuilds...only a handfull of us seem to be able to pull it off.

btw stay away from trimetal bearings, use and size everything for the OEM aluminum babbit bearings
 
Ok, at least i will know the range i should have.On the crank tho, yey or neh on turning it?Would it have strength or smoothness issues from being turned?
 


our crank is already weak because of the split journals...by removing 20 thou from both journals you are weakening it even further... I would not suggest it but for a bone stocker it might be fine....but stay away from welded and re ground crankshafts.
its real s***** to destroy a bunch of parts and time from skimping on one component
 
A few things should be known about building engines to be a success, it's not about luck, it's not hit-or miss either, it is about paying attention to detail and the basic knowledge of engine theory that will be the deciding factor between "YAY", or "NAY". Knowledge is power, and that knowledge can directly relate to power put down to the pavement. Know what your clearances should be, and check them, if they are not correct, make them correct. Make sure the everything is straight, true, and square, if it is not, make it straight, true, and square. Know what you are working with, if you don't know, learn. If you don't want to learn, don't do it. Make it 100%, or don't make it at all or you will look foolish with parts bouncing off the pavement surface. Oil bearing clearances, machine finish surfacing, side clearances, piston ring clearance, torque spec and sequence. Become friends with your local machinist if you have one in your town.
 
there's those but aside from making sure the oil passages are cleaned up in the bad spots and deleting the filter bypass most of my mods are to better control oil return and windage....moar pah
 
You must log in or register to reply here.
Back
Top