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Location:
Geelong, Vic
Registered:
November 2004
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 18RG piston clearance
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Sat, 04 December 2004 22:43
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ive been reading forums for weeks but i havent come across anything that covers cam lift/duration max before pistons need to be re-cut.... does anyone know?
i have 2 18rg's one 88253 with 88251 cams the 2nd is 88230 with 88231  (3 bolt) cams + 0.050 o/s pistons
plus a set of wade #137 cams
Help 
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Location:
Rocklea qld
Registered:
February 2003
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Re: 18RG piston clearance
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Sat, 04 December 2004 23:30
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if your going over size piston insted of the higher conpression standard size ones then using the 88231 cams will be alright...but use them on the 88250 head or if possible get a 88270 head to use with the 88231 cams...that wa7y if you want some porting later on you can get more out of it.
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Location:
nth ringwood, Victoria
Registered:
August 2002
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Re: 18RG piston clearance
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Sun, 05 December 2004 00:24
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the 137 wade grind has heaps more duration but should be fine for 1mm over size 9.7to 1 pistons but the solexes will be hard to tune my mate has the trd rally profiles which would be better 304 and 288 they are at clive cams in nunawading and would make a good 18rg go heaps better than the 137 grind
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Location:
Geelong, Vic
Registered:
November 2004
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Re: 18RG piston clearance
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Sun, 05 December 2004 00:27
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what i want to do is use the wade cams in the 88253 head on the std block but im unsure if the valves will hit the pistons (without putting them in the head putting it together and turning it over by hand)
Has anyone used this cam grind before WADE #137 im intrested in how they went
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Location:
nth ringwood, Victoria
Registered:
August 2002
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Re: 18RG piston clearance
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Sun, 05 December 2004 00:44
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what pistons have you got 8.8 or 9.7 to 1 also the 137 that i used in my stroker 2tg hit the std pistons from memory so it will be the same on yours but you can use the trd rally 1s which are better in my opinion the 137 has to much duration which keeps the valve open to long hence they hit, the high lift with less duration is the go for these ,ask andrew vibert he has used about every cam spec in his stroker 2tg and he went back to the trd rally spec 1s for the best torque and power and less valve train hassle
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Location:
Geelong, Vic
Registered:
November 2004
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Re: 18RG piston clearance
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Sun, 05 December 2004 06:42
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from what i can tell they are just the std 8.7:1 (0.050 o/s)comp they only have a 4mm dome and small flycuts for the valves. do you know what the 308/308 or 308/288 cams are worth $$ roughly ball park
What are your thoughts, im trying to build an offroad motor that will work for me all day?
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Location:
nth ringwood, Victoria
Registered:
August 2002
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Re: 18RG piston clearance
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Sun, 05 December 2004 07:02
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its pointless having hot cams if the comp is low you need hi comp at least 10 to 1 and with the 137 you will loseheaps of cylinder fill if your cams are already welded up it will just be a regrind to these specs
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Location:
Geelong, Vic
Registered:
November 2004
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Re: 18RG piston clearance
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Mon, 06 December 2004 00:01
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For Race configuration- Treat the head to a competition port and polish with the most aggressive cams usable. You may need a custom intake manifold because stock manifolds will be the limiting factor to the port job. The big valves and dual valve springs are mandatory (they are bigger than the largest stock valves). The crankshaft and rods must be prepped- stress reliefed, heat treated, line-bored. Optionally rods may be upgraded to Carillos. Piston clearance is critical since these are high revving engines, follow the piston manufacturers tolerances. Piston valve pockets must also match the camshaft and valves used. The oil pumps in the 2TG and 18RG are different from the single cam models, try to use the original Twin Cam pumps, specially when converting to the 3T block. If available the TRD oil pumps must be used for the 2000cc 2TG. The oil pan has to baffled, specially for race and rally use. For the Full Race set-up use 320 intake and 304 cams. For the Rally set-up use 304 /288 or 304/272 cams. For the Street racer, the 304/304 set-up is very streetable and have a nice mild lobe at idle. It is very discrete! These cams cannot be used with stock pistons!! (The 288/272 cam set-up maybe used with stock pistons, as long as the head has not been cut.) Naturally adjustable gears are needed for the cams.
So it appears that in order to avoid having the piston pockets recut not to go over 288/272 cams
taken from
http://www.toysport.com/Technical%20Information/2t g_18rg_3tg_tech_notes.htm
Does anyone know the specs for any of the TRD cams
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