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Spark plug heat range?


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#26 I'm a Red Motor fiend

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Posted 19 March 2018 - 06:05 PM

Just pull the frocken thing apart man. You bought a second hand motor because it's had some work done. You want it to perform and go fast. How can u even begin to tune it and get the most out of it when u have no idea about its internals?
I don't get why people buy shit, know nothing about it, can't get it to work and then post here asking for the solution?
There is no answer until you know what's going on inside it.
Sounds like u might have a good setup there, but u need to get to know it.

#27 Donyboom

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Posted 20 March 2018 - 01:28 PM

Just pull the frocken thing apart man. You bought a second hand motor because it's had some work done. You want it to perform and go fast. How can u even begin to tune it and get the most out of it when u have no idea about its internals?
I don't get why people buy shit, know nothing about it, can't get it to work and then post here asking for the solution?
There is no answer until you know what's going on inside it.
Sounds like u might have a good setup there, but u need to get to know it.


Absolutely I agree. I come here for the knowledge. Otherwise I’m poking around the dark with my dick in my hand. Thanks for the tip!

I’m currently trying to ascertain if it is indeed engine internals or just a cooling issue. I don’t have bulk cash or a shed big enough to pull an engine out atm so will have to wait 6 months till I get a new place.

So I changed the thermostat to a 71c. Lowered the timing to above curve. Lowest the water temps got was 76. The head was a fair bit cooler. 90 degrees at cruise but if I went up a hill or put the foot down I could watch the needle rise to 100-105c. When cruising it would slowly fall to 90c. Water temps under load did climb to about 82c. No pinging it drove pretty good plenty of power.

I might leave it like this till I can pull the engine again and match the cam and head etc as suggested. I wouldn’t think that radiator issues would see head temp fluctuations like this? The fact that the head temps move around according to load yet water temps are stable indicates to me that the combustion is hot AF.


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#28 biga064

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Posted 20 March 2018 - 05:54 PM

Hi Whats the gap on your plugs ?? If that photo is to go by that spark plug gap is way to big !! You want 32 to 40 thou tops in a high comp motor !!! Cheers 

 



#29 LC-GTR-1969

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Posted 20 March 2018 - 06:04 PM

Nothing with engine internals will make this engine behave remarkably different to most other warm 202s. There is a problem, you just have to find it. 

 

You said you are running 24 total in the info you have, ie 24 at 6k rpm... Your timing curve is somewhat unusual tbh, so I would look there... You very likely just need more octane than what you are giving it. 

 

Your engine temps have nothing to do with it IMHO. I would look further at possible misreads as things are not aligning. 

 

Plug temp range is associated with cylinder pressure and excess combustion chamber temps. To need any more than 7 heat range in a naturally aspirated 202 is crazy and likely nothing but a band aid for another issue. Your plugs are more than likely damaged from pinking rather than heat range misalignment IMO. 

 

Fix the pinking, run good fuel and you will be fine. 

 

Is it an open chamber head by any chance? open chamber has less quench so 11:1 will struggle with a small cam on 98. With a typical 30/70 11:1 would be fine though. 



#30 lawn bowls

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Posted 20 March 2018 - 08:55 PM

going by the colour of the spark plug is lean need to richen it up a bit.on picture number 1 looks like there is some piston on the top of the electrode strap.



#31 Donyboom

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Posted 20 March 2018 - 10:04 PM

going by the colour of the spark plug is lean need to richen it up a bit.on picture number 1 looks like there is some piston on the top of the electrode strap.

 

Yeah I fattened it up today so will see. I'll give it a week or so and check them again. did you mean pitting?

 

I agree that curve is odd. I mean from what I've read any advance after 3500 is useless so really i am only getting 19degrees adv.

 

I am running bp ultimate. honestly its best pick of the pack here on the sunny coast and it aint fing cheap.

 

Its a blue L head if thats what you mean by open chamber.

 

I got the cooling system checked over today and pressure is fine. bottom hose is cool enough to hold so its not that. I am getting intake air temps of 50c 



#32 Donyboom

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Posted 20 March 2018 - 10:07 PM

Hi Whats the gap on your plugs ?? If that photo is to go by that spark plug gap is way to big !! You want 32 to 40 thou tops in a high comp motor !!! Cheers 

yeah 1.3mm. I just left them gaped as per efi black motor specs but have seen others here commenting that 35 thou is good. im running msd 6a box and blaster coil.


Edited by Donyboom, 20 March 2018 - 10:19 PM.


#33 I'm a Red Motor fiend

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Posted 21 March 2018 - 08:36 AM

Nothing with engine internals will make this engine behave remarkably different to most other warm 202s. There is a problem, you just have to find it.



Yep there is a problem - unknown cam specs, whether or not it's dialled in right and unverified static/dynamic compression. That's what I meant by internals.
Without knowing, it's like clutching at straws and going round in circles wasting time. It will never perform at it's full potential.

#34 lawn bowls

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Posted 21 March 2018 - 02:23 PM

im using united 98 which is mobil and finding it very good



#35 LC-GTR-1969

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Posted 21 March 2018 - 05:25 PM

yeah 1.3mm. I just left them gaped as per efi black motor specs but have seen others here commenting that 35 thou is good. im running msd 6a box and blaster coil.

 

I run about the same or slightly more compression than you, albeit with an open chamber head, and I run 40thou as a general rule. Car is fine running up to 60 thou though. If I go to track I run the lower figure like 30 thou. 






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