I was told that a 179 head will be ok on a 202 block. I was wondering if this is right or am I best of only using a 186/202 heads?
202
Started by
_uctorana_
, Nov 15 2005 09:07 AM
10 replies to this topic
#2
Heath
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Posted 15 November 2005 - 09:37 AM
I think you can stick a 179 head on a 202 block, but you'll need to use the 179 rods etc. Don't take my word for it though mate.
#3
_uctorana_
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Posted 15 November 2005 - 10:14 AM
Thanks Heath.... I have also rung a someone that only deals with toranas and they said the same thing that i can run a 179 on my 202.
I just wanted a head that will be suited to my torrie as I was sold a 186 yella terra from Dinkums but i had the casting number checked and it was a 161 head not a 186 now they are shitty with me as they think its all one big saga and they cant help me with anything. Not my fault they said it was a 186 in the first place. So I now have to go back a third time to get my money back for that head and get this 179 from a friend.
Hope all this works.... miss driving the torrie
I just wanted a head that will be suited to my torrie as I was sold a 186 yella terra from Dinkums but i had the casting number checked and it was a 161 head not a 186 now they are shitty with me as they think its all one big saga and they cant help me with anything. Not my fault they said it was a 186 in the first place. So I now have to go back a third time to get my money back for that head and get this 179 from a friend.
Hope all this works.... miss driving the torrie
#4
shanegtr
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Posted 15 November 2005 - 12:10 PM
I would have though all red heads were the same apart from some small changes to compression. Am I on the right track there?
#5
Dr Terry
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Posted 15 November 2005 - 05:09 PM
Hi Guys.
Yes, that's correct there are basically only 2 types of red 6 cyl head if you ignore the adjustable/non-adjustable rocker gear situation. The 2 types are small (or kidney shaped) combustion chamber & large (or open) chamber. 179 & 186 heads are near identical, & both these are the same as a 202 head except for the rocker gear.
The smaller chamber heads are seen on 130, 138, 149, 161 & 173 motors & the larger heads are found on 179, 186 & 202 motors. All of these motors in stock form have compression ratios in the region of 8.8 to 9.4.
The exceptions are the special-order low compression versions of the small motors (149, 161 & 173), these just make use of an open (larger) chamber head to drop the compression, usually to under 8:1. The other exceptions are the 2 XU1s where they used the smaller head on the larger 186/202 motors to raise the compression to over 10:1. Problem there, is today's low octane petrol, it was hard enough in the 70s to stop these from detonating (pinging).
The only ones I haven't mentioned are the low comp versions of the 186 & 202, to acheive these they used pistons with the required dish in the top of the piston, to drop the compression.
It's not that you can't fit 1 type of head to your motor, they will all bolt on, it's what you end up with that matters.
Dr Terry.
Yes, that's correct there are basically only 2 types of red 6 cyl head if you ignore the adjustable/non-adjustable rocker gear situation. The 2 types are small (or kidney shaped) combustion chamber & large (or open) chamber. 179 & 186 heads are near identical, & both these are the same as a 202 head except for the rocker gear.
The smaller chamber heads are seen on 130, 138, 149, 161 & 173 motors & the larger heads are found on 179, 186 & 202 motors. All of these motors in stock form have compression ratios in the region of 8.8 to 9.4.
The exceptions are the special-order low compression versions of the small motors (149, 161 & 173), these just make use of an open (larger) chamber head to drop the compression, usually to under 8:1. The other exceptions are the 2 XU1s where they used the smaller head on the larger 186/202 motors to raise the compression to over 10:1. Problem there, is today's low octane petrol, it was hard enough in the 70s to stop these from detonating (pinging).
The only ones I haven't mentioned are the low comp versions of the 186 & 202, to acheive these they used pistons with the required dish in the top of the piston, to drop the compression.
It's not that you can't fit 1 type of head to your motor, they will all bolt on, it's what you end up with that matters.
Dr Terry.
#6
_draglc_
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Posted 15 November 2005 - 05:39 PM
161 heads are good on 202s, they up the compression. i have one on one of my 202s and its awesome.
#7
_uctorana_
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Posted 16 November 2005 - 08:39 AM
is your 161 head stock? cause mine isnt.
#8
_lonemonaro_
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Posted 17 November 2005 - 03:41 PM
Hi Dr Terry,
What sort of compression could one achieve from a 202 Red motor coupled with a 186s head ?
How does a 202 head rocker gear differ from a 179/186 and what sort of rocker gear should a 186s head have on a 202 block.
Kind regards
George
What sort of compression could one achieve from a 202 Red motor coupled with a 186s head ?
How does a 202 head rocker gear differ from a 179/186 and what sort of rocker gear should a 186s head have on a 202 block.
Kind regards
George
Edited by lonemonaro, 17 November 2005 - 03:44 PM.
#9
Dr Terry
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Posted 17 November 2005 - 08:27 PM
Hi George.
If you fit a 179 or 186 head to a 202 your comp will stay the same because the combustion chambers are the same size for all 3 (we should do sticky on this).
The thing with the rocker gear is that both the 179 & 186 had adjustable tappets & the 202 were fixed. The ideal set-up for a 202 red is a nicely flowed 179 or 186 head (Yella Terra or similar) & the rocker arms & pushrods off the same engines to match.
This is what GM-H did with the XU1, except they went one step further & used a small chamber 149/161 head to raise the comp to 10.25, a bit high for today's fuels. But the point is 202 XU1 heads used 149/161/179/186 rocker gear & pushrods.
Dr Terry.
If you fit a 179 or 186 head to a 202 your comp will stay the same because the combustion chambers are the same size for all 3 (we should do sticky on this).
The thing with the rocker gear is that both the 179 & 186 had adjustable tappets & the 202 were fixed. The ideal set-up for a 202 red is a nicely flowed 179 or 186 head (Yella Terra or similar) & the rocker arms & pushrods off the same engines to match.
This is what GM-H did with the XU1, except they went one step further & used a small chamber 149/161 head to raise the comp to 10.25, a bit high for today's fuels. But the point is 202 XU1 heads used 149/161/179/186 rocker gear & pushrods.
Dr Terry.
#10
Stedz_lc
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Posted 17 November 2005 - 08:38 PM
Would usin a 138 head also raise comp to above the 10:1 mark?
#11
_73LJWhiteSL_
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Posted 21 November 2005 - 12:09 PM
Would usin a 138 head also raise comp to above the 10:1 mark?
The smaller chamber heads are seen on 130, 138, 149, 161 & 173 motors & the larger heads are found on 179, 186 & 202 motors. All of these motors in stock form have compression ratios in the region of 8.8 to 9.4.
This is what GM-H did with the XU1, except they went one step further & used a small chamber 149/161 head to raise the comp to 10.25, a bit high for today's fuels. But the point is 202 XU1 heads used 149/161/179/186 rocker gear & pushrods.
If you asking what the exact compression ratio will be i don't know but i think that 138 head on a 202 uping the compression has already been answered above.
Steve
Edited by 73LJWhiteSL, 21 November 2005 - 12:12 PM.
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