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Registered:
May 2005
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Location:
Nor Calif USA
Registered:
June 2002
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Re: 18rg pistons, what kind?
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Tue, 05 July 2005 18:07
 
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No that a stock RG piston. those are small domes.
for the back firing.
check your Dizzy and the carbs
most likely it your dizzy if it the old points dizzy.
if there no grease on the lobes or old and warn out
it will do that.
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Location:
Brisbane
Registered:
October 2002
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Re: 18rg pistons, what kind?
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Wed, 06 July 2005 06:32
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as above
just check the valve seating, this may be causeing backfiring
pistons are usually 20 thou {0.5mm} smaller at the ringlands, so u will be able to see the rings slightly
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Registered:
May 2005
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Re: 18rg pistons, what kind?
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Wed, 06 July 2005 07:12
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so these are 18RG low comp pistons? being 8.5 comp ration. would this be why i only get 100psi on a comp test.
if this is the case i might be putting in some new pistons as i want a higher ration, what pistons should i look at getting?
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Location:
Brisbane
Registered:
October 2002
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Re: 18rg pistons, what kind?
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Wed, 06 July 2005 08:25
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your compression is too low, whats the valve lash set at
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Registered:
June 2004
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Location:
adelaide
Registered:
May 2002
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Registered:
June 2004
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Re: 18rg pistons, what kind?
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Wed, 06 July 2005 09:54
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not from what i've heard. 88253 is the lowest at 8.4:1, and the rest are all higher than that.
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Registered:
May 2005
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Re: 18rg pistons, what kind?
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Wed, 06 July 2005 10:16
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i have an 88230 head with 88210 timing cover. ive got a 250 head which ive been quoted $540 for a reco.
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Registered:
June 2004
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Re: 18rg pistons, what kind?
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Wed, 06 July 2005 10:27
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i feel sorry for you, coz i could do it for practically nothing.
what parts are included in that qouted rebuild?
the 88230 head would be best, where's the rest of the 88210?
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Registered:
May 2005
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Re: 18rg pistons, what kind?
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Wed, 06 July 2005 10:31
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the 250 head is pretty corroded, needs alot of weldin, has few bents valves.
I bought the car as is, so what was done in the "engine rebuild" or what parts were used is beyond me.
i can get 250 covers and pistons.
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Location:
Tamworth
Registered:
August 2004
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Re: 18rg pistons, what kind?
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Wed, 06 July 2005 10:41
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The 210 model of 18rg was the one with 9.7-1 comp. Hence why it was the most powerfull stock of all 18rgs even tho the port casting qaulity is crap. In an effort to regain horsepower because of the lower comp in the later models, they made the valves bigger. Still didnt match the 210.
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Location:
adelaide
Registered:
May 2002
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Re: 18rg pistons, what kind?
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Wed, 06 July 2005 10:46
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| THE WITZL wrote on Thu, 13 February 2003 23:31 |
well.. i have a bit of info on the head numbers on 18R-G's that has helped answer some of my questions....
| Quote: |
> Here's some head numbers off Al's 18RGs:
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> 88250:
> - 49657 single spring early rgu single dump ex ok head small studs on ex
> - 52978 same as above
> 88253:
> - 73086 double spring late rgu good head to start with large studs on ex
duel dump man
> - 62744 single late rgu still good head may be small stud ex should be
single dump
> - 81784 double spring late also
> - 87278 double spring late also
> 88270: these are ale efi heads all double springs alll good heads these
are the ones you use
> - 35140 biggest ports biggest valves no smog ports best casting
> - 08037
> - 49383 very late head newest ive seen
> ?:
> - 81225 same as above double late rgu if the head is a 11111-88253 not a
11111-88270
> 88253 88270s would be the heads of choice since these need very little
work from the factory these willl make lots of power with little porting
they will make a lot more power with a lot of porting the castings are a lot
thicker around the ports so there is a lot of room
the 88250s can be made good but the ex studs should be changed up to 10mm
ones for best sealing
all of these engines should have 8.5s to 1 but the efi 88270 heads they
should have 8.3 to 1
just be glad you dont have any of those 11111-88230 or 88210 heads they are
good paper weights
hope this helps your info of what you got there sounds like my garage
i think i have 15-18 heads right now
cary
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: 18rg pistons, what kind?
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Wed, 06 July 2005 11:24
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information on the internet varies WILDLY. i dont even believe what i wrote there anymore.....
My current beliefs:
88210 $ 88230 = 9.7:1
8825* = 8.7:1
88270 = 8.3:1
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Registered:
May 2005
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Location:
Nor Calif USA
Registered:
June 2002
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Re: 18rg pistons, what kind?
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Thu, 07 July 2005 07:50
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| THE WITZL wrote on Wed, 06 July 2005 21:24 |
information on the internet varies WILDLY. i dont even believe what i wrote there anymore.....
My current beliefs:
88210 $ 88230 = 9.7:1
8825* = 8.7:1
88270 = 8.3:1
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just get some 20R dome pistons and they will
give you a compression ratio of 9.to1
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