MIGHTYMOUSE

iTrader: (59)

i used to run tr6's and dont recall having a problem.

i now have the all pro heads and they require a gasketed spark plug, so i run autolite ar 3911's.

well after not so many miles (to me) the gaps are opening up and may be contributing to my misfire problem.

any spark plug geeks out there that can find me a ngk tr-6 equivalent that is gasketed?

repeat, i want the gasketed version of the tr-6 from ngk.

if it is not available i would entertain a full tip version of the ar 3911

thanks

white2001s10

iTrader: (4)

Ever looked at an Autolite AR472?
Take a look and see if they fit your need.
I can post a pic later on tonight.
They will handle about anything in the way of abuse and heat.

MIGHTYMOUSE

iTrader: (59)

id prefer not any of the AR plugs as they wear too fast for my daily driver.

these are my findings.

first of all an ar 3911 is 2 heat ranges colder than a tr6.. hmm

second, the ngk equivalent of the ar 3911 is pn 7173 (i ordered these)

third, the ngk gasketed equivalent of their own tr6 is a pn 6962

fourthly, the gasketed ngk plug in between those two heat ranges is the 6097

stevieturbo

By a gasketed plug, is that just a regular plug with a sealing washer below ??

Nearly all plugs in the UK have a compressable washer. Getting normal LS1 style plugs that have no washer etc here is a bit of a mission !!

Have you asked around Jap circles ? Subarus normally use PFR6B, 6 heat range, double platinum. Good for over 300bhp on a 2.0l. Above that, PFR7B has worked fine for many making over 500bhp.
I also used the PFR7B's on my old twin turbo Rover V8. Generally a good plug. I'll take a pic of one later. Should have some lying about.

Regular steel tips could be something like

CHRISPY

MM is making about 1000 horsepower.

MM does the TR6 protude too far or is there some other issue with that plug?

Thanks,

stevieturbo

7's dont appear to have any cold fouling issues on any engines Ive ever run.



Bad pic, Ignore the oil, they came from an engine that melted a piston.

stevieturbo

500bhp, from a 2000cc engine ( or in some cases 2300cc-2500cc ), is around 250bhp per litre. MightyMouse is making a huge amount of power, but still not at that level, so I think my comparisons are still valid.

Pro Stock John

iTrader: (34)

I've run TR8's and AR3911's with my stock heads. Only thing that creeped me out with the gasketed plugs was not knowing when they were tight... Never used those before.

I'm going to AllPro's in a couple of weeks so I'll have to check this out.

stevieturbo

I assume the gasketed plugs you refer to are indeed the type I pictured ??

Virtually every car in the UK uses them, whether they be local cars or foreign ( Vauxhall, Ford, Rover, German, Jap etc etc. )

Not sure what the torque specs are for tightening, but they really dont need to be tight at all. Not as if they are going anywhere. Worst thing you can do is tighten them too much, and strip the threads off the head.

Once they have been compressed once, that initial soft feeling is gone, and tightening just feels normal...well to me anyway.

MIGHTYMOUSE

iTrader: (59)

chris the tr6 has a cone seat like a stock lug nut, the all pros are not machined for this cone and need a washered plug like that picture

stevie, those may be nice plugs but im no expert on plugs and im doing good to just get this far.. i would have no idea how that plug there would work/fit in an aftermarket ls1 cylinder head... and dont feel like just trying it out for the beneifit of mankind.

KAOS

iTrader: (5)

i thought that all the ngks have the washers on them. im pretty sure i installed mine with the washers. if so should i take them off?????

stevieturbo

Normal LS1 heads use TR6's that seal on a taper. They do not have a washer.



And I thought I posted this answer the other day?? seems to have dissappeared

2001WS6Vert

How is the gap opening up? I know you've got a lot of power but the only way I have seen gaps widen is from either long term wear or detonation. Is the metal just burning away? I would think there may be a problem that is the real cause and not the plugs.

stevieturbo

I appreciate you dont want to experiment too much, or take advice from an unknown source. But....

To an extent, plugs are just plugs. TR6's are a very basic plug, nothing fancy about them at all. But they are tried and tested. I was quite reluctant to use such a plug, firstly as I'd have to purchase from the US, and secondly, its been a long time since Ive used a steel tipped plug in any engine. I couldnt easily fnd a cross reference to a similar plug here in the UK, so ended up buying form the US.

In a similar fashion, the gasketed plugs I mentioned are also fully tried and tested, albeit on different engines. PFR6B are actually OE plugs fitted to many Jap spec cars, and listed for a few UK/Euro cars. 6 being the heat range as per any NGK.

I was in the garage today, and had a look at my old 853 castings. Thought this might be useful.
Stock LS1 plug recess is basically flat, with a very slight taper.


Here is a TR6 plug, tightened into that plug hole, as viewed from combustion chamber.


And I was quite surprised when I tried the PFR7B "gasketed" plug into that same hole. I didnt actually think it would have fitted, otherwise I would have just used these plugs in my own engine ( well new ones )


There's actually very little difference in depth. The gasketed plug doesnt protrude just quite as far, but very little in it TBH.
I couldnt say if thats a good thing or a bad thing.

Obviously I dont know how this would compare to your All Pro heads.

But from the above info and pics, is there any reason why you cant just use a tapered seat plug as per TR6 in your All Pro heads ? Even if it meant you machining a slight taper into your plug recess ?

MIGHTYMOUSE

iTrader: (59)

you may be right, but its an autolite racing plug, the tip design is different and only the edge sparks.. and this edge would wear away much faster than the flatsurface of a normal tip.. kurt up at wheel said i have flat out too many miles on them anyways.

stevie, your pictures are good.

the all pros are machined flat, no tapered seat. you can imagine that with a tapered plug 1. the plug would sit shallower in the chamber and 2. the taper would f-up the first threads on the plug holes when you torque it in there.

i agree you can definitely use a gasketed plug on a tapered head.

what i am saying about 'not trying' is that i have never heard of those part numbers you called out, and have no idea how close they are to an ar 3911 dimensions and heatrange... so i am sticking with what ngk says is their cross to the 3911, being ngk 7173

MIGHTYMOUSE

iTrader: (59)

i went and took a pic of the ar 3911

stevieturbo

It does seem strange, that NGK supplying all over the world, use plugs that wont cross reference between continents.

Not sure what plug numbers they use in Ozzie land, but I did hear BPR6EF mentioned as a cross to a TR6. ( or IT20 Denso Iridium )

BPR6EF would be the style of part number I am more familiar with, although havent actually tried to get them here, as I bought 5 sets of TR6's when I first got my LS1 running.
The PFR6B number is an OE number, but basically just a 6 heat range, double platinum tipped plug. 7 Likewise. They dont make an 8 in that style though.
Or same as a Denso IK22 ( Iridium )


Any pics of your Autolites ??

LTLHOMER

iTrader: (10)

Look above your post he posted a picture...I run an autolite racing plug as per w2w's request when they tuned the car. I'll get the p/n from it when I out in the garage later to work on the ride.

stevieturbo

Weird....that post wasnt there when I asked the question !

Whats the idea behind the short electrode ?

MIGHTYMOUSE

iTrader: (59)

stevie, i havent been looking up any platinum type plugs, maybe your number is correct for that.

the pn is AR 3911 like i allready said lots of times above.

i guess the spark is better exposed that way.