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Author Topic: prechamber replacement  (Read 340 times)

October 12, 2018, 11:31:22 am

fatmobile

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prechamber replacement
« on: October 12, 2018, 11:31:22 am »
 I'm putting together an engine using the good parts from an engine with a cracked block.
 The prechambers are cracked.
 I drove some out of old heads awhile back and glad I have a stash of them.

They seem to go in pretty easy, but they didn't seat down far enough.
So I had to drive them out and scrape some carbon off.
 When I drove them back out it seemed pretty easy too.
 They are in there firmly and flush now so I know they are the right size but do they usually drive out easily when newly installed?
 marked with 24 on the side CuH?
Topline head.


Tornado red, '91 Golf 4 door,
with a re-ringed, '84 quantum, turbo diesel, MD block

Reply #1October 13, 2018, 11:33:57 am

libbydiesel

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Re: prechamber replacement
« Reply #1 on: October 13, 2018, 11:33:57 am »
They should be a bit of a press fit.  Not easy movement.  You could peen the bore of the insert to displace metal a bit and make it a tighter fit. 
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Reply #2December 15, 2018, 09:47:50 am

smutts

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Re: prechamber replacement
« Reply #2 on: December 15, 2018, 09:47:50 am »
The prechambers overlap the block somewhat, does that help them stay in place?

Reply #3December 15, 2018, 12:09:47 pm

libbydiesel

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Re: prechamber replacement
« Reply #3 on: December 15, 2018, 12:09:47 pm »
They overlap the block, but there is some flexibility to the head gasket.  If they are at all loose, they can wear into the head gasket and wear it away to to cause extreme damage in a surprisingly short amount of time. 
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #4December 15, 2018, 04:51:25 pm

smutts

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Re: prechamber replacement
« Reply #4 on: December 15, 2018, 04:51:25 pm »
Is there any sort of noise typical of a precup burrowing it's way to freedom?

A long passed 1.6 GTD of mine, developed almost overnight a horrendous "clackclackclack,etc" from one cylinder, which wasn't due to fuel, or valves, didn't vary with load, not heavy enough for a big end.  I always assumed it was a failing piston, or little end, but compressions with turning the engine by hand were reasonably even. Well no big hole in the piston at least.

It carried on like that, not getting worse, for some 10,000 odd miles before it ate it's oil and the Missus drove it, ignoring  the idiot proof flashing red light and alarm.
She asks me, "Is it supposed to do that?"
I ask "How long has it been doing that?
She says "Oh, about 30 miles"
Sigh. ::)

The car has been manhole cover lids for about eight years now, but I still wonder what that noise was?

 

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