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Location:
Hobart
Registered:
June 2002
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replaced head gasket... found cams were swapped!! (18rg)
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Mon, 23 August 2004 23:53
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the other week i noticed by head gasket was gone. This was confirmed by oil in water, water in oil. losing coolant, low compression on two cylinders.
anyway, took the cam cover off with the motor set on number one tdc compression stroke, but the markers on the cams were not at the top!. From the valves i could tell she was on no. 1 tdc compression.
so i sat there for a while sratching my head, turning the motor over watching the cams go through the cycle. Then i realised the inlet and exhaust cams look similiar to the eye, and that if they were swapped the notches in the cams would come back where they should be.
so i proceeded to swap the head gasket.
Things started to fall into place, i bought this car off a 'mechanic' and it never went aswell as my old 18rg, and the mechanic has supposedly rebuilt it. Also, it always was pretty tappety/noisy in the valve gear.
so i swapped the cams over, inlet to exhust and vise-vesa. Checked the valve clearances and they are all within spec. lined up the cams, with the nothces at the top. Everything went back together fine.
She started, runs heaps better. Quieter, more power. just generally better. Slightly rougher idle. I'm running programmble efi, and it needed richening up all over the mid range.
running sweet now! 160 psi +/- 5 psi on all cylinders (9.7:1 pistons)
sorry for long post...
cheers
Chris
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Location:
Adelaide
Registered:
September 2003
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Re: replaced head gasket... found cams were swapped!! (18rg)
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Tue, 24 August 2004 00:01
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curiously do you measure the psi when cold or hot
mine gives 120 when cold and 140 when hot (+/- 5), and it is a real bastard to start on a cold morning.
oh and i ain't loosing coolant and what i can tell i ain't loosing oil.
i believe the coppper head gasket (and o-ringed block) is lowering my compression somewhat
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Location:
Hobart
Registered:
June 2002
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Re: replaced head gasket... found cams were swapped!! (18rg)
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Tue, 24 August 2004 01:49
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it was measured staright after head gasket was replaced, be fore i started it. so yeah, cold.
do you take all spark plugs out, and open the throttle wide open.
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Location:
Canberra
Registered:
December 2002
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Re: replaced head gasket... found cams were swapped!! (18rg)
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Tue, 24 August 2004 02:21
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I managed to squeeze 195psi out of the last rg that i rebuilt, not sure how accurate the guage was tho.
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Location:
Adelaide
Registered:
September 2003
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Re: replaced head gasket... found cams were swapped!! (18rg)
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Tue, 24 August 2004 02:54
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yeah wide open with all sparks removed... 
anyone wanna swap a block good for forced induction for a standard rg block? o-rings already done for you 
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Location:
Tasmania
Registered:
May 2002
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Re: replaced head gasket... found cams were swapped!! (18rg)
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Tue, 24 August 2004 08:39
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I doubt there would be any difference in swapping the inlet cam to the exhaust, as they are both ment to be the same. And there is no point if your valve clearances are already ok. The cam timing must have been out originaly, and now you have set it right. The notch at the top is only for timing as you know, and the engine will run fine if they are swaped around, provided the cam timing is right.
160psi is good. I have a 1812cc 2T-G with 305 cams, and I got 150psi. (Always lower dynamic compression with big cams).
If you are keen, the next thing is to make a degree wheel, get a dial gauge and find the duration of the cams, and the exact timing.
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Location:
Hobart
Registered:
June 2002
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Re: replaced head gasket... found cams were swapped!! (18rg)
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Tue, 24 August 2004 09:24
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meant to be the same ay, well if thats the case i guess the difference in power could have just been timing. I also could have been down on compression longer than i thought i suppose.
the clearances must have been set for the cams as they are now though, because they are heaps better (not that i measured them before, just going by the fact it doesn't rattle so much now)
cheers
Chris
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Location:
Adelaide
Registered:
September 2003
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Re: replaced head gasket... found cams were swapped!! (18rg)
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Tue, 24 August 2004 11:08
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| RA40Celica wrote on Tue, 24 August 2004 09:53 |
i bought this car off a 'mechanic' and it never went aswell as my old 18rg, and the mechanic has supposedly rebuilt it.
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Good to hear it is running better.
Make a mental note NEVER to go to this "mechanic" again !!!
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Location:
Tasmania
Registered:
May 2002
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Re: replaced head gasket... found cams were swapped!! (18rg)
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Tue, 24 August 2004 11:16
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Chris, I just realized that was you. The exhaust and inlet cams will often have a slightly different part number. They are the same casting, and same grind, the only differences being the timing notch and the part number. The difference in part number will be a crooked number stamped in the middle of the base number, hard to explain in short.
I assume you checked all the valve clearances.
You will need to get that machine out on Baskerville soon. I maybe doing private practice in a few weeks time, not sure. Maybe you could go as quick as that Corona wagon!
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Location:
Hobart
Registered:
June 2002
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Re: replaced head gasket... found cams were swapped!! (18rg)
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Tue, 24 August 2004 23:13
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yeh ive seen the crooked number. is the crooked '1' for intake or exhaust?
i could be interested in the private practice sessions. I would have to get my cams license, and get bonnet pins, etc, wouldn't i? It was inspiring watching on sunday.
Changed my diff the other week, i discovered that it had a 3.9:1 diff in it. I put a standard 4.1:1 back in. I can notice the difference mainly in 5th gear at highway speeds, hangs on up the hills better.
Btw, i have my old twin side draught carbies sitting in the cupboard. Would you or asher be interested in buying them? they are the early 18rg ones. They are in fairly good condition i think.
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Location:
Brisbane
Registered:
October 2002
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Re: replaced head gasket... found cams were swapped!! (18rg)
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Tue, 24 August 2004 23:54
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i have the same problem, my cams are back to front, all u would've had to do was set the cams up on TDC on cyl 4, thats what i did,
the cams ARE identical except the notch is 180 degs out from int to exh
i just got mine tuned last night, very nice now, i now have 150psi all round
look at my sig and see the previous compression 
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Location:
Newcastle
Registered:
April 2003
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Re: replaced head gasket... found cams were swapped!! (18rg)
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Wed, 25 August 2004 06:33
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So what sort of power you making now?
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Location:
Brisbane
Registered:
October 2002
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Re: replaced head gasket... found cams were swapped!! (18rg)
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Wed, 25 August 2004 08:12
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not sure, more tho
when the cams are dialled in i'll get it dyno'd
there is a shop near my new work that does a 30 min dyno run for $30
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