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Location:
Brisbane
Registered:
November 2002
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18R woes - what do these do?
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Sat, 18 September 2004 14:21
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Hi guys
I decided to reco the cylinder head on my 18RC as I don't want any problems with it. So, as I didn't have the chance to pull off the head I bought a spare on for a few bucks and reconditioned it as well. Now that I'm out of pocket for the reconditioning, I've noticed that the heads are vastly different!
On the head the engine currently has, you can see that there are two extra bolts at the front on the driver's side. The new head doesn't have either of these holes and is just dlended down smoothly. The second head I have is off an 18R (not 18RC), and I knew they had a minor difference as they didn't run the EGR setup, but unfortunately didn't notice these major differences until I'd shelled out my hard earned, removed the old one and sat them side by side.
So am I screwed or can I use this other head I've just reco'd? The lower bolt hole has a spring which sticks into the head, I think it's something to do with the timing chain guide.
The other one has a bolt with a thing sticking out of it, which appears to be something to do with oil temp/oil pressure but doens't actually have a sender coming off it. I thought it may act like a thermostat and extend-retract with temperature/pressure changes.
Does anyone know if, or can anyone hypothesise that, I would be able to run this head with no issues?
I'd hate to have done all this work and spent all this money for naught.
[Updated on: Sat, 18 September 2004 14:22]
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Location:
Rocky Mountains, Canada
Registered:
May 2002
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Re: 18R woes - what do these do?
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Sat, 18 September 2004 16:42
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Strange, i thought only the 18R had those, and the 18RC didnt.
Oh well.
They are chain tensioner bolts.
The top one is for oil regulation to the guide.
The bottom one has the spring behind it to apply pressure.
The new head without these will be fine.
It just does the upper timing chain tension in a different way.
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Location:
Brisbane
Registered:
November 2002
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Location:
Rocky Mountains, Canada
Registered:
May 2002
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Re: 18R woes - what do these do?
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Sun, 19 September 2004 05:20
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The other type of head does still have an upper tensioner, its just not visible from outside like the older one.
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Location:
Brisbane
Registered:
November 2002
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Re: 18R woes - what do these do?
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Sun, 19 September 2004 09:15
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Cool I'l have to have a look-see...
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Location:
Brisbane
Registered:
February 2003
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Re: 18R woes - what do these do?
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Sun, 19 September 2004 09:39
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i remember these ... older engine has fixed tension on the upper chain - newer (if i can use that word here) used oil-pressure regulation on the tension spring.
as long as spring is healthy, it should not be issue.
i think the pressure regulation made sure at high revs there was no slack in the chain.... but it's been so long since i spoke to the engineer/mechanic about this...
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Location:
ipswich queensland
Registered:
April 2004
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Re: 18R woes - what do these do?
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Sun, 19 September 2004 10:26
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ive worked out wat happend.
i took the head off a 74 model engine and u needed a 75 model one to be the same bolt holes and stuff
i just hope it still works for u as uve just got it reconditioned
sorry bout the stuff up
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Location:
Brisbane
Registered:
November 2002
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Location:
Canberra
Registered:
December 2002
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Re: 18R woes - what do these do?
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Mon, 20 September 2004 02:53
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just get the old style chain tensioner off the origional block and it will be fine, i have been told that these are better for rattle than the oil (newer) style but im not sure how true it is.
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Location:
Rocky Mountains, Canada
Registered:
May 2002
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Re: 18R woes - what do these do?
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Mon, 20 September 2004 06:29
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| Jason wrote on Mon, 20 September 2004 12:23 |
just get the old style chain tensioner off the origional block and it will be fine, i have been told that these are better for rattle than the oil (newer) style but im not sure how true it is.
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The tensioner he is talking about is on the head, and it cant be changed between the two different styles of heads.
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Location:
Canberra
Registered:
December 2002
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Re: 18R woes - what do these do?
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Mon, 20 September 2004 06:34
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There you go i personally have never seen them 
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