| Author | Topic |
|---|
Location:
Rocklea qld
Registered:
February 2003
|
|
18rg conrod bearing caps..tension???
|
Fri, 11 February 2005 10:19
|
 |
|
what tension are the rod caps done up to...yes ive searched and only found head, cams, and crank settings
|
|
|
Location:
Brisbane CBD
Registered:
September 2004
|
|
Re: 18rg conrod bearing caps..tension???
|
Fri, 11 February 2005 12:38
|
|
|
hey i have the 18r-c specs as follows 39 to 48 Ft/lbs
|
|
|
Location:
Adelaide
Registered:
June 2003
|
|
Re: 18rg conrod bearing caps..tension???
|
Fri, 11 February 2005 12:54
|
|
Sorry Ra28Freak but that's not correct. They have different tightening torques.
I just checked up the book for you and the figures for 18R-G are as follows:
46.3 - 50.6 ft.lb
6.4 - 7.0 kg.m
(1977 edition)
I hope you got this before you did the job.
|
|
|
Location:
Rocklea qld
Registered:
February 2003
|
|
Re: 18rg conrod bearing caps..tension???
|
Sat, 12 February 2005 09:49
|
|
|
thanks guys...ill do them to about 48 so its in between it all...
|
|
|
Location:
Brisbane CBD
Registered:
September 2004
|
|
Re: 18rg conrod bearing caps..tension???
|
Sat, 12 February 2005 14:13
|
|
|
lol its for my engine so i hope he did too thats why i said i only had the rc specs
|
|
|
Location:
Rocklea qld
Registered:
February 2003
|
|
Re: 18rg conrod bearing caps..tension???
|
Sat, 12 February 2005 21:20
|
|
well theres been an accident with the engine actually...ive put the bottum end together..gone to turn it over buy hand and it doesnt turn. ive already put sump and timing case on also. it turns out that i may have used a 18rc crank instead of 18rg and the bearing journals on the conrods are slightly different so when i tension up the rods the rods get stuck and jam up  so now i gotta strip it agian and put a rg crank in
|
|
|
Location:
Adelaide
Registered:
June 2003
|
|
Re: 18rg conrod bearing caps..tension???
|
Sun, 13 February 2005 00:14
|
|
Yeah, that should be fine, I reckon that's what we used and we haven't had any issues that we know of. Haven't had any spun bearings or horrible noises.
Sorry if I sounded a little abrupt before Ra28Freak, I only skimmed your post and than made a quick trip to the book and posted. I read your post afterwards and realised that you weren't implying that those figures could be used on the RG.
Just for interest, does anyone know why they use different figures?
The tightening torques are different for the Crankshaft bearing caps too.
I've read somewhere that 2TG and 3TG cranks are forged and am wondering if the same is true of the 18RG cranks.
Is there a way to distinguish between 18RG and 18RC cranks?
Later,
Steve M
|
|
|
Location:
Adelaide
Registered:
September 2003
|
|
Re: 18rg conrod bearing caps..tension???
|
Sun, 13 February 2005 00:57
|
|
I have heard that the 18rg crank is forged and the 18rc crank isn't but again only heard.
does it make sense to be tighter because there is more of an explosion happening in the top end that tightening it that little bit more is just reccommended?
people 100: when i chucked my rg together the original crank had a crack in it (bad apparently  ) so i stole the crank out of an rc and used that instead. the bearings are the same fro an rc and an rg so it should be alright.
when we oiled it all up and tightened to the specified torque we also found that we couldn't turn the bottem end either and were pretty worried, but once we used the starter moter to turn the car over it turned fine.
I think that because it is freshly built and the tolerances are pretty tight, that would explain why it is hard to turn.
|
|
|
Location:
townsville NQLD
Registered:
February 2004
|
|
Re: 18rg conrod bearing caps..tension???
|
Sun, 13 February 2005 03:39
|
|
i would expect the 18rc and 18rg cranks are identical.
ben,
the reason the it is hard to turn the engine over is likely to be that the 18rc (revved out less often ) crank will be less abused and hence less worn and tighter clearances.
what u are best off doing is put the first cylinder bearing cap on (plenty of oil) and turn the motor over by hand 5 times...... then repeat this process for the rest of the cylinders.
if you bolt everything together at once, means u will struggle to get it to move from the bolt together position, but once its moved it should continue to loosen up as u wind it over.
also, are they standard bearings??? are they over sized??
have u plastiguaged the bearings??? what are the clearances??
my bearings were all like 2 thou and the recomended is between 2 and 4 thou(i think). mine was pretty tight to turn over in the begining but loosened up
|
|
|
Location:
Adelaide
Registered:
June 2003
|
|
Re: 18rg conrod bearing caps..tension???
|
Sun, 13 February 2005 03:42
|
|
We used 18RC bearings and used the 18RG torque figures and it was hard to turn.
I reckon that the new bearings are just firmer than the old ones (hence the need to run in a rebuilt engine)
The other reason that it was hard to hand crank was that the bores had just been oversized for the new pistons and new rings.
A rebuilt engine should always be harder to hand crank. This is also due to less lubrication.
We had to use two batteries to start the engine (out of the car with fairly average connections) because we couldn't get it to go over compression.
The torque figures should be fine. I've had a look at some of the other figures comparitively between the two 18R series engines and it seems that where the design of the parts is the same, it is only the parts relating to the crank and the camshaft drive gear (aux shaft) the use different figures.
It seems though, that the RG uses finer tolerences for tightening torques. A few of the figures for parts of the engine are within the range set for the 18RC but the RG has a smaller range. ie. 18RC range = 68.7-83.2ft.lb, 18RG range = 72.3-79ft.lb
I thought this was interesting, along witht he fact that 18GR's came with a 3-angle valve grind from the factory.
You guys might not find interest in these things but then again, I lead a pretty dull life.
|
|
|
Location:
Rocklea qld
Registered:
February 2003
|
|
Re: 18rg conrod bearing caps..tension???
|
Sun, 13 February 2005 08:44
|
|
|
ok i even had a starter in it and it wouldnt turn..turned out that instead of someone marking the rod and cap on the same side they marked them opposite sides. so when i put the pistons in i put the marks together and in fact they were suppose to be opposite. hence the reason it was tight and jammed up...its all good now. ive done onem up to check it and turns fine now...also know for a fact rc and rg cranks are interchangable now but the rg is alot strong because its forged.
|
|
|
Location:
Brisbane CBD
Registered:
September 2004
|
|
Re: 18rg conrod bearing caps..tension???
|
Sun, 13 February 2005 09:30
|
|
yay its not dead 
|
|
|
Location:
Adelaide
Registered:
June 2003
|
|
Re: 18rg conrod bearing caps..tension???
|
Sun, 13 February 2005 10:05
|
|
Well, that is good news.
I'm glad it is now going together well.
|
|
|
Location:
Tamworth
Registered:
August 2004
|
|
|
Location:
townsville NQLD
Registered:
February 2004
|
|
Re: 18rg conrod bearing caps..tension???
|
Mon, 14 February 2005 10:55
|
|
| jeffro RA28 wrote on Mon, 14 February 2005 18:50 |
Hey, as far as i know the parts numbers for the rg's and rc's are the same, except for cam parts.(yer i know its a bit l8)
---jeff---
|
so that means if i order a 18rc tappet cover gasket, it will be the same as an 18rg one???
|
|
|
Location:
Rocklea qld
Registered:
February 2003
|
|
Re: 18rg conrod bearing caps..tension???
|
Mon, 14 February 2005 11:16
|
|
it could be if you stretch it 
|
|
|
Location:
Adelaide
Registered:
June 2003
|
|
|
Location:
Tamworth
Registered:
August 2004
|
|
|
Location:
Adelaide
Registered:
June 2003
|
|
|
Location:
Rocklea qld
Registered:
February 2003
|
|
Re: 18rg conrod bearing caps..tension???
|
Fri, 18 February 2005 07:52
|
|
|
one thing i wanna know is can you put 18rc pistons onto 18rg rods?
|
|
|
Location:
townsville NQLD
Registered:
February 2004
|
|
Re: 18rg conrod bearing caps..tension???
|
Fri, 18 February 2005 10:00
|
|
havent u tried that already???
i would assume they fit
|
|
|
Location:
Rocklea qld
Registered:
February 2003
|
|
Re: 18rg conrod bearing caps..tension???
|
Fri, 18 February 2005 10:24
|
|
|
i just used complete rc rods and pistons but im thinking of changing to rc pistons with rg rods
|
|
|
Location:
Adelaide
Registered:
June 2003
|
|
Re: 18rg conrod bearing caps..tension???
|
Sat, 19 February 2005 00:18
|
|
I can't see why not, all the critical measurements should be the same, just that your compression ratio will go to 7:1 
|
|
|
