pre-com. chambers

Spore · 12-27-06, 03:03 PM

Hi all-

I recently removed the head frorm a 3b. The pre-combustion chanbers all seemed very loose; you can move them back and forth in the head with your fingers. When the head is set face down on a table, the chambers all fall out (not just one). I am more familiar with newer diesels where they snuggly fit in the head and tools are needed for removal. Anyway, this doesn't seem right - how tight should they be seated in the head?

Help?

brownbear · 12-27-06, 05:46 PM

that sounds odd, I thought they would be a pressed fit..... But I have never had the head off mine.... I look tonight at the FSM to see how they remove them in the manual.

cruiser_guy · 12-27-06, 06:14 PM

They can be quite loose. Chances are the pre-cups and the head are both cracked anyways. Have you magnafluxed the head yet or examined the pre-cups closely?

Spore · 12-28-06, 03:33 PM

Yes, the head and pre-cups have been checked. Everything checks out fine except for this "looseness" thing. The manual I have simply calls for a screwdriver to remove them and soft hammer to tap them back in, but that suggests to me that they shouldn't be as loose as they are.

Deny · 12-28-06, 03:49 PM

When I was changing the head gasket on my 3B, the cups were all cracked, but still had to give them a few wacks to get them out. The new ones had to be smacked quite a few times. I don't think they should be loose at all.
Cheers,
Deny

brownbear · 12-28-06, 05:02 PM

Call OZ where they sell the replacement heads and ask the question.

Hopefully an expert head guy will know. Then post it here, so we can all be experts

cruiser_guy · 12-28-06, 10:40 PM

When I had a damaged head repaired the guy used a center punch around the edge of the pre-cup to keep it in so te looseness thing is likely not a big concern. They are sandwiched between the block and the head when it is all together and they have an indexing lobe as well to keep them from rotating.

UpsideDown · 12-29-06, 08:58 AM

The pre cups should be a slight interference fit. I would recommend installing new cups if you have had the old ones out for any reason.

Rob Lassman may have some available. (Radd Cruisers)

crushers · 12-29-06, 09:04 AM

the precups can not fall into the combustion chamber since a good portion sits pinched between the block and the head outside the chamber.
if the cups are in good shape then red locktight them into place and set the head back on, you will be fine.
if they have ANY cracking then replace them with new.

cheers

12-27-06, 03:03 PM	#1
Spore IH8MUD Rookie Join Date: Apr 2006 Posts: 62	pre-com. chambers Hi all- I recently removed the head frorm a 3b. The pre-combustion chanbers all seemed very loose; you can move them back and forth in the head with your fingers. When the head is set face down on a table, the chambers all fall out (not just one). I am more familiar with newer diesels where they snuggly fit in the head and tools are needed for removal. Anyway, this doesn't seem right - how tight should they be seated in the head? Help?

12-27-06, 05:46 PM	#2
brownbear Mod in Hibernation Join Date: Sep 2004 Location: Where diesels purr and turbos whine TLCA# 15584 Posts: 6,183	that sounds odd, I thought they would be a pressed fit..... But I have never had the head off mine.... I look tonight at the FSM to see how they remove them in the manual. __________________ -84 BJ60, Finally on the FN road! -91 FJ80, wife's ride Iron Butt award winner of the Cruise Moab 08 !

12-27-06, 06:14 PM	#3
cruiser_guy IH8MUD Lifer Join Date: Jan 2003 Location: Mixco, Guatemala/Cranbrook & Vancouver, B.C., Canada TLCA# 16387 Posts: 7,362	They can be quite loose. Chances are the pre-cups and the head are both cracked anyways. Have you magnafluxed the head yet or examined the pre-cups closely? __________________ '82 BJ60 H55 tranny, AXT turbo 3B diesel, high nickel alloy head, A/C, BDS lift, factory PTO, Aussie rear locker, OEM LSD front, 4:11's, 32's, PERFECT frame! '76 FJ55, 3B turbo, alloy head, H41 tranny, 3 sp. transfer, 33's, A/C, PTO winch, long range tank! '67 FJ45LV shop project c/w 3B turbo diesel transplant & H41 4 speed, 3 speed transfer, PTO! www.wirrell.com

12-28-06, 03:49 PM	#5
Deny IH8MUD Lifer Join Date: Jan 2005 Location: Fort St John, BC TLCA# 11568 Posts: 1,369	When I was changing the head gasket on my 3B, the cups were all cracked, but still had to give them a few wacks to get them out. The new ones had to be smacked quite a few times. I don't think they should be loose at all. Cheers, Deny __________________ Diesels Rule 81 BJ42 Check out my endless fix up progress at http://forum.ih8mud.com/ca-bc-peace-canyon-toyota-swamp-donkeys/152995-bj42-winter-fix-up.html

12-28-06, 05:02 PM	#6
brownbear Mod in Hibernation Join Date: Sep 2004 Location: Where diesels purr and turbos whine TLCA# 15584 Posts: 6,183	Call OZ where they sell the replacement heads and ask the question. Hopefully an expert head guy will know. Then post it here, so we can all be experts __________________ -84 BJ60, Finally on the FN road! -91 FJ80, wife's ride Iron Butt award winner of the Cruise Moab 08 !

12-28-06, 03:33 PM	#4
Spore IH8MUD Rookie Join Date: Apr 2006 Posts: 62	Yes, the head and pre-cups have been checked. Everything checks out fine except for this "looseness" thing. The manual I have simply calls for a screwdriver to remove them and soft hammer to tap them back in, but that suggests to me that they shouldn't be as loose as they are.

12-28-06, 10:40 PM	#7
cruiser_guy IH8MUD Lifer Join Date: Jan 2003 Location: Mixco, Guatemala/Cranbrook & Vancouver, B.C., Canada TLCA# 16387 Posts: 7,362	When I had a damaged head repaired the guy used a center punch around the edge of the pre-cup to keep it in so te looseness thing is likely not a big concern. They are sandwiched between the block and the head when it is all together and they have an indexing lobe as well to keep them from rotating. __________________ '82 BJ60 H55 tranny, AXT turbo 3B diesel, high nickel alloy head, A/C, BDS lift, factory PTO, Aussie rear locker, OEM LSD front, 4:11's, 32's, PERFECT frame! '76 FJ55, 3B turbo, alloy head, H41 tranny, 3 sp. transfer, 33's, A/C, PTO winch, long range tank! '67 FJ45LV shop project c/w 3B turbo diesel transplant & H41 4 speed, 3 speed transfer, PTO! www.wirrell.com

12-29-06, 08:58 AM	#8
UpsideDown IH8MUD Addict Join Date: Sep 2006 Location: Koksilah, Vancouver Island, BC Posts: 575	The pre cups should be a slight interference fit. I would recommend installing new cups if you have had the old ones out for any reason. Rob Lassman may have some available. (Radd Cruisers) __________________ 1978 FJ40 - parts vehicle - PM me 1987 HJ61 VX 5spd - loaded - daily driver 1981 BJ42 - ARBs, Warns, oba, ps, h55f, hws, soa

12-29-06, 09:04 AM	#9
crushers IH8MUD Lifer Join Date: Feb 2004 Posts: 9,793	the precups can not fall into the combustion chamber since a good portion sits pinched between the block and the head outside the chamber. if the cups are in good shape then red locktight them into place and set the head back on, you will be fine. if they have ANY cracking then replace them with new. cheers __________________ pulling this info out of my ass so take it with a pound of salt "People are poor because they don't spend money wisely, tough sh!t !!! " John Galt 09/22/08 "educate yourself. Sorry if that seems too blunt." John Galt 11-01-08 Wayne in Ontario http://www.ivoac.ca join today

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