riotwarrior
Full Access Member
Hmm..guess my price is ok and especially for a set I should have asked for more, but that wouldn't help everyone! A good deal is when it is good for both parties!
Pre-Cup Needed
- Thread starter 19887.3IDI
- Start date
icanfixall
Official GMM hand model
Read the ebay add closely. The pic is of a precup but the description states its a exhaust valve seat. Sure hope if someone buys this its a cup and not a seat. Or engines do have exhaust valve seats and they are replaceable too. An added note no matter where you buy cups you will need to measure the recession or protrusion from the head. They are allowed to be above or below the head surface only a max of 2 1/2 thousands. No more and no less. If yours measures 3 thousands above or below the head surface it will cause a head gasket leak...
JosieGallows
Full Access Member
I asked the seller, It's a cup. But for $35 a piece is too high.
I found new ones for $7 each. They had 16 in stock and I bought 8.
And how do I measure recession or protrusion? Sled gauge or feeler gauge?
19887.3IDI
Registered User
Where did you find them for $7 each?
riotwarrior
Full Access Member
mag base and dial indicator zeroed out will tell you if it's above deck or set it to 0.000 then add in 0.005 below deck and measure and if it's 0.020 yer ok but if not..yer screwed gotta get them machined ..
This is not something most people can do at home..
Feeler gauge would work so long as you have clean head and true flat bar to measure from/under
JM2CW
Good luck hope it turns out in your favor!
JosieGallows
Full Access Member
mohavewolfpup
Diesel Wolf Puppy
Are precups in the cylinder heads? never had one apart before. How hard are they to get out?
JosieGallows
Full Access Member
Hard enough to break most of my screw drivers and bent brass rods.
You need a 1/4 inch hard steel drill bit jammed into a piece of wood. Hammer on the wood.
mohavewolfpup
Diesel Wolf Puppy
then I suppose you hammer away at the center of it? or along the edges? Don't have one in front of me currently. Just knowledge storing
JosieGallows
Full Access Member
Hammer the center of the wood block where the drill bit is. I had my drill bit sticking out and I hit the part sticking out. Hit it hard as can or else the cup won't come out.
icanfixall
Official GMM hand model
There actually is a Rotunda tool made for removing these precups.Its a "J" hook on the end of a slide hammer. I used a piece of brass rod big enough to fit thru the injector nozzle hole in the head. then hammer on the soft brass till it pops out.
riotwarrior
Full Access Member
Got a pic of that bad boy? I'll build one and use it ROFL...
Just called local machine shop, guy seems know his *****, maybe more n me
anyways $125 hole to sleeve + sleeve cost can send precups to be welded and fixed, damn...we had a good talk, I feel quite confident in that shops capability to machine my stuff.This may mean the turbo core gets ahem....warmed over this summer if my shop pans out ok.
Hmm...
Turbo block all modded out sleeved, decked, blue printed every piston same protrusion..oh ya...complete balance hell ya...Oh ya..pics of tool Gary...????
icanfixall
Official GMM hand model
Al, I will search out a pic of the tool but brass weld rod or just brass round stock works fine. About the welding of the precups. Please ask the guy what rod they use. Someone here mentioned that the precups were not inconel but plain steel and magnetic...
JosieGallows
Full Access Member
Al, I will search out a pic of the tool but brass weld rod or just brass round stock works fine. About the welding of the precups. Please ask the guy what rod they use. Someone here mentioned that the precups were not inconel but plain steel and magnetic...
Depends... Offshore cups are magnetic steel (Dieselcastwelding) and the USA ones are Inconel (Ford Genuine or International)
The steel ones supposedly never crack.
icanfixall
Official GMM hand model
Josiegallows... I tig welded inconel on major steam turbine rotors and stationary diaphragms for 3 years. It does not crack now does it wear of like steel thats magnetic. Steam will cut it but it takes many more years to do that. Steam will cut stellite too but it takes a long time to do that too. I ported some Dieselcast Welding precups and they sure are inconel. That was 9 years ago now. You may be correct with what they are selling now but not what they sold back then. I still have one of those heads but its cracked from reaching over 300 degrees when a freeze plug poped out pulling the Grapevine grade. That engine had 5200 miles on it after a full rebuild with lots of machine work done like line boring and block decking plus sleeving all 8 cylinders.
