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Engine Specific Info and Questions => IDI Engine => Topic started by: Kudagra on March 31, 2010, 11:14:05 am

Title: PreCup question
Post by: Kudagra on March 31, 2010, 11:14:05 am
On my recently resurfaced head...my precups dont fit snug..actually they fall out if I turn the head over.

Is there a way to fix this or do I have a pretty aluminum paperweight?
Title: Re: PreCup question
Post by: Rabbit on Roids on March 31, 2010, 01:12:10 pm
ive seen people peen the cups in there. dont know if i would personally do it for the fact that it adds a small amount of surface area to the head. or maybe im just over thinking that whole surface area thing. anyway, seen them peen'd in before.
Title: Re: PreCup question
Post by: Kudagra on March 31, 2010, 01:33:18 pm
ive seen people peen the cups in there. dont know if i would personally do it for the fact that it adds a small amount of surface area to the head. or maybe im just over thinking that whole surface area thing. anyway, seen them peen'd in before.

I might be coming through with a 1.9 head so this might all be moot. Im going to try shuffling precups between a few heads I have and see if I can get them to fit any better.

Can the precups actually Fall out into the cylinder?? I thought the edge of the cylinder would hold them in. Doesnt the fire-ring of the head gasket lay right across the center of the cup?
Title: Re: PreCup question
Post by: clarkrep on March 31, 2010, 02:09:36 pm
Yes, the headgasket supports part of it. I've never had one fall out but have heard about it. I just can't see how they could fall out since they're so tall.
I'm sure there are carnage pics here somewhere.
I might have some extras you can try. I live like 10 miles from Baldwin City. IM me.
Title: Re: PreCup question
Post by: Kudagra on March 31, 2010, 03:22:31 pm
Yes, the headgasket supports part of it. I've never had one fall out but have heard about it. I just can't see how they could fall out since they're so tall.
I'm sure there are carnage pics here somewhere.
I might have some extras you can try. I live like 10 miles from Baldwin City. IM me.

Did I chase you down on I70 between Lawrence and Topeka? Stopped at the service center? I was in my service van.
Title: Re: PreCup question
Post by: clarkrep on March 31, 2010, 03:37:04 pm
Maybe, I could have been driving a silver 79 four door na diesel or black 83 GTI with a TD.
How long ago? 
Aaron
Title: Re: PreCup question
Post by: Kudagra on April 01, 2010, 09:46:36 am
Maybe, I could have been driving a silver 79 four door na diesel or black 83 GTI with a TD.
How long ago? 
Aaron

Few weeks maybe. It was black rabbit.
Title: Re: PreCup question
Post by: burn_your_money on April 01, 2010, 09:55:00 am
If they are that loose I personally wouldn't trust just peening.

I'm not sure if knurl is the right word for what I'm thinking of but if it is then that's what I would do.

Clear as mud?
Title: Re: PreCup question
Post by: Rabbit on Roids on April 01, 2010, 11:11:05 am
like what they do to ratchet handles for traction?
Title: Re: PreCup question
Post by: wolf_walker on April 01, 2010, 04:21:56 pm
like what they do to ratchet handles for traction?

As in knurling valve guides.
Title: Re: PreCup question
Post by: truckinwagen on April 01, 2010, 04:23:33 pm
while knurling is a good way to increase outside diameter, I would like to see the knurling machine that would happily do it to the inconel of our precups...
Title: Re: PreCup question
Post by: NintendoKD on April 02, 2010, 03:16:55 am
superalloy=knurling NO, Cracking/shattering YES
Title: Re: PreCup question
Post by: wolf_walker on April 02, 2010, 05:28:48 pm
Softer pre-cups would make some things a lot easier if they'd hold up.  I know some exist on cheapy "new" heads,
do they last?
Title: Re: PreCup question
Post by: NintendoKD on April 02, 2010, 07:46:35 pm
for the average joe maybe, but for the boost limit seeking enthusiast, like me, that is a resounding no.