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186 performance build Lj Torana


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#1 natcamp10

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Posted 23 April 2018 - 09:34 PM

Hey guys
I would like to start with Great forum this is and thanks to all who actively help here
I’m building a virgin 186 by block number for my torry ( thinking to go 15” tho over for the first bore)
I’m after some combos that have worked
It will be a street car but would like to get it reving up to 7000 rpm makin 240hp plus
I’ve knocked the core plugs out and had look inside and it seems good to start with ..
I’m thinking of using a blue motor 202 crank in ,get it balanced with some comp rods and light weight pistons but have not committed to anything yet ( I’m running the w50 box behind it ) so do I need to worry about a lighter flywheel as what I’ve read here is that a light weight flywheel helps with shifting on the Aussie boxes , is this the same with the celiac boxes ??
For the head I’m torn between a h comp 161 yt head ( I have a virgin head maybe if I can get hold of tk to do the head work which I’ve been looking at on this forum or the new alloy 12 port heads from yt .. ( running 45mm triples )I have a red 202 with a 161 yt combo with a mild cam that goes well pretty good in the lj but like all of us I want it going a bit harder
Any learnings from you guys would help , Ive been following old Jonnos post on the wed how to build a hot six and some awesome Advise is in the documents (just couldn’t find me a 173 blue motor to start with )you guys have used em all lol
So shoot me some reconditions plz
Old Jonno if ya out there would love it if you got involved in this
Cheers fellas 🍺

#2 rodomo

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Posted 23 April 2018 - 10:04 PM

Gidday.

#3 natcamp10

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Posted 23 April 2018 - 10:45 PM


Gidday.

Hey mate

#4 jd lj

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Posted 24 April 2018 - 07:23 AM

Hi mate,
Welcome to the forum.
Depending on your budget you could consider a jzed head too.

#5 I'm a Red Motor fiend

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Posted 24 April 2018 - 07:25 AM

You gotta start with the heart of the combo (cam) and build it around that. If u want to go fast you have the wrong gearbox (ratios)

#6 natcamp10

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Posted 24 April 2018 - 09:01 AM


You gotta start with the heart of the combo (cam) and build it around that. If u want to go fast you have the wrong gearbox (ratios)

so would you recommend staying with the Aussie 4

#7 Ice

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Posted 24 April 2018 - 09:07 AM

so would you recommend staying with the Aussie 4


Aussie 4 speed and 7000 rpm wont happen for very long

#8 I'm a Red Motor fiend

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Posted 24 April 2018 - 11:02 AM

For a strong streeter and if your not going to side step the clutch much, a rebuilt aussie 4 with M21 ratios not M20 (to keep the cam on the boil when shifting) will suffice.....

#9 natcamp10

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Posted 24 April 2018 - 11:29 AM

What about the w50 5 speed box what’s the common opinion on those , are they all rev but no go just reading into the above quote from I’m a red motor , could I change the diff ratio ? Or change the ratio in the box , sort of had my heart on a 5 speed but if it just causes hassles I will keep it a4 spend
I do have a spare m21 sitting in the shed , would I be able to put that box straight behind it ? M21 was the v8 box correct ?

#10 I'm a Red Motor fiend

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Posted 24 April 2018 - 12:42 PM

That's the trade off unfortunately. For a strong streeter with a large cam short gears like 3.55 or even better 3.9's are what you want but with the 4 speed on the highway it's horrendous.
The 5 speed will make short gears ok on the highway but because of its ratios the cam will drop out of the power band when you shift.
This is the decision only you can make with how you intend to use the car.....

#11 I'm a Red Motor fiend

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Posted 24 April 2018 - 12:48 PM

And yeah, M21 is the V8 box but real easy to convert a 6cyl M20 to M21 ratio.
M21 ratio box with 3.9 gears works real nice keeping the cam where it likes to be when you shift. It's basic, it's not overly strong but for a weekend warrior it's cheap and effective.

#12 LC-GTR-1969

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Posted 24 April 2018 - 05:17 PM

You gotta start with the heart of the combo (cam) and build it around that. If u want to go fast you have the wrong gearbox (ratios)

 

I tend to disagree a little here... I believe you should build the engine (including cam selection), around the head and the flow characteristics. The head is the heart IMHO not the cam- the cam just dictates when the heart will beat (so to speak). I would pick the best head you can afford and build the bottom end around that. Ie if you have a high flowing inlet but moderate exhaust, you might run more duration on exhaust than inlet, or vise versa. The valve area can also help ascertain the ideal valve closing events and LSA. 

 

But you are right, in reality the HEAD AND CAM is the key to any engine. They both need to be right and work together. 



#13 I'm a Red Motor fiend

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Posted 24 April 2018 - 05:42 PM

Comes down to budget I guess. You have a good point on a max effort combo. But if you were to run a cam with say no more than 230 degrees duration so it's more street able I don't see the point spending $3000+ on a head that flows say 300+ HP

#14 natcamp10

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Posted 24 April 2018 - 10:49 PM

And yeah, M21 is the V8 box but real easy to convert a 6cyl M20 to M21 ratio.
M21 ratio box with 3.9 gears works real nice keeping the cam where it likes to be when you shift. It's basic, it's not overly strong but for a weekend warrior it's cheap and effective.



I like it , what’s a good streetable cam range , this is not a drag car so I’m seeing what you guys are saying

#15 natcamp10

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Posted 24 April 2018 - 11:16 PM

This what I’ve got in the car already
202 with a 161 h comp yt stage 3 head running what I think is a standard cam or a very mild grind , I didn’t build this motor I got it from over east with the triples and the 5 speed
It’s got flat tops in it not sure about bore sizes etc cause I’ve never pulled it down , so I’m starting to think to build a bottom end and use this head if it checks out when I pull off this motor .. I’ve checked the numbers and it traces back to a early 161 yt head
I will get it flow tested ,fit the bigger valves if required and some shrouding , the manifold is already port matched to the head
So after the flow test is when I should choose the cam to suit the head ??
The 186 bottom end I’m planning to put under it
So IM thinkin to run a blue motor 202 crank balanced to 50/50 with some comp rods and light wieght pistons , a good balancer out the front with a light wieght flywheel on the back
Cam range to kick in around 3/4000 and rev to 6/6500 but I’m not sure here cause it’s got to be street able as well , no point having this fully cam up motor if yoi Cannot use it
Was thinking msd ignition with a 2.5 inch exhaust

Am I on the right track

#16 rexy

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Posted 25 April 2018 - 12:34 AM

For a street car you want lots of torque through the biggest rpm range you can.
More cubic inches, more torque. Speak to your preferred cam grinder and be honest wth them.

The Toyota 5 speed boxes are very good. Much nicer shift feel than the Aussie boxes and should be plenty strong enough behind a NA Holden six.
Will let you run a numerically higher diff ratio to hide your missing bottom end torque if you go for a biggish cam.

#17 jd lj

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Posted 25 April 2018 - 07:10 AM

Nathan,
You mentioned that you have triple carbs on your existing engine, what type are they and what manifold are they on? Are these the ones that you plan to use on the new motor?

A 2.5" exhaust will be suitable.

#18 I'm a Red Motor fiend

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Posted 25 April 2018 - 08:15 AM

Is there any reason you are set on the 186 block? Maybe pull down the 202 and inspect the bore and bore size. You never know it may only need a hone and new rings? It's probably already got blue motor rods and even if it needs and can take a rebore good hypers only cost around $300.
You will spend more money turning the 186 into a 202 when you already have a 202?
Sounds like the head you have is a really good starting point, get it freshened get it flowed. Get it cc'd so you can settle on a compression ratio to suit your cam. I think you have done some homework and are on the right track. Yes to the balancer and flywheel you mentioned. MSD ignition if you want, decent extractors and the 2.5 inch exhaust.
A cam with 250 degrees duration with a lightened flywheel, short diff gears and the right gearbox ratios is perfectly street able (maybe not as a daily) I reckon and will make good power with what you are proposing.

#19 natcamp10

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Posted 25 April 2018 - 08:33 AM

Nathan,
You mentioned that you have triple carbs on your existing engine, what type are they and what manifold are they on? Are these the ones that you plan to use on the new motor?

A 2.5" exhaust will be suitable.



Hey jd
45mm dcoe side draft Weber’s on lynx manifold and yup these puppies are going on

#20 jd lj

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Posted 25 April 2018 - 08:54 AM

Ok, what model of 45dcoe's are they? Eg 9's, 13's,152's etc? Unfortunately the old lynx manifolds aren't great from what I've been told. You'll notice that the runners for numbers 1 and 6 (IIRC) curve around whereas the others are a lot straighter, this makes the runner lengths and volumes differ.

#21 natcamp10

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Posted 25 April 2018 - 09:06 AM

Is there any reason you are set on the 186 block? Maybe pull down the 202 and inspect the bore and bore size. You never know it may only need a hone and new rings? It's probably already got blue motor rods and even if it needs and can take a rebore good hypers only cost around $300.
You will spend more money turning the 186 into a 202 when you already have a 202?
Sounds like the head you have is a really good starting point, get it freshened get it flowed. Get it cc'd so you can settle on a compression ratio to suit your cam. I think you have done some homework and are on the right track. Yes to the balancer and flywheel you mentioned. MSD ignition if you want, decent extractors and the 2.5 inch exhaust.
A cam with 250 degrees duration with a lightened flywheel, short diff gears and the right gearbox ratios is perfectly street able (maybe not as a daily) I reckon and will make good power with what you are proposing.


I think your right , the 202 I’ve got in it probably already got the blue crank in it as well lol , I suppose the 186 block was cause it just sort of came my way , I did want to keep the car on the road while I mess with a motor but the more I look into it I’m better off pulling down the old engine and seeing what’s in it , also my young fella just started his apprenticeship in mechanics so it’s a father son build of a engine

#22 natcamp10

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Posted 25 April 2018 - 09:19 AM

Ok, what model of 45dcoe's are they? Eg 9's, 13's,152's etc? Unfortunately the old lynx manifolds aren't great from what I've been told. You'll notice that the runners for numbers 1 and 6 (IIRC) curve around whereas the others are a lot straighter, this makes the runner lengths and volumes differ.


152 mate and yeah it’s a odd ball manifold , it runs a bush setup for the connecting shaft , I’ve spent a fair bit of time jetting and choking the carbs right , they go really well now , dropped my choke sizes from 40 to 36 and dropped my main jet size and put richer idle jets in , no flat spot in transition to sencondaries , pulls hard through the rev rang


152 mate and yeah it’s a odd ball manifold , it runs a bush setup for the connecting shaft , I’ve spent a fair bit of time jetting and choking the carbs right , they go really well now , dropped my choke sizes from 40 to 36 and dropped my main jet size and put richer idle jets in , no flat spot in transition to sencondaries , pulls hard through the rev rang


I’m now chasing the rose joint setup manifold

#23 Ice

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Posted 25 April 2018 - 10:33 AM

You want the cam to kick in before 3000 rpm in my opinion dont go to big on a cam other wise it will be a pig to drive on the street

#24 gtrboyy

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Posted 25 April 2018 - 12:28 PM

For a streeter build it to make torque & not something that has to 7k rpm.

 

Start with blue/black 202 bottom end then work out budget & where car will spend majority of it's time street cruising or highway? How drags or circuit work?



#25 natcamp10

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Posted 25 April 2018 - 12:36 PM

You want the cam to kick in before 3000 rpm in my opinion dont go to big on a cam other wise it will be a pig to drive on the street

I got a cm205d stage 2 cam that’s in the parts I got with car as well , looking at the specs it’s a stage 2 cam fur.050” 214/214vlift
, it’s looks like it’s the biggest stage 2 in the dynote before it goes stage 3 , it looks near on new , could be a good street cam , what do you think




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