Spark plugs.

[arcturus]

Hi, which are the best spark plugs to use on B20b? also is 95 the best to use or should I use 98 ?

[amaz'in]

Brand or type?

I would say...and speak from experience (I have an Amazon with B20b) NGK plugs.

Standard plug is a BP6HS or, for fast/motorway driving etc,..use a BP7HS.

There is a resistor version of this plug if the standard plug causes noise on your Radio, the plug number then has an R in it for Resistor eg, BPR6HS etc

However....when Igot my car..it had been fitted with BP8HS plugs...a very cold plug to stop the engine running on etc...

But I had real problems starting the car..in fact...on one occasion I simply couldn't start it..period..even if i heated the Plugs over our Gas cooker!! with the engine heater plugged in ALL night too.. and the engine has done less than 5,000 miles since a full re-build.

I local Rally shop said 8's were crazy...they do not even fit them in 500 bhp Subaru cars...so sold me some 6's..I fitted them and the car started instantly!

Only slight problem is..it now runs on every now and again...just for a split second..so I just purchased some 7's to try...see if it hit's the spot perfectly.

I always run my B20b engines on Shell V max (UK 99ron octane)...these engines would have originally been run on 100 octane...on my last Amazon I experimented with fuel...and V-Max was the best...even BP Ultimate wasn't that great.

On top of this I add Tetraboost..the only genuine lead additive..even though my head has been modified for unleaded.

I also run my 940 Turbo on V-Max too..


James

[B20F]

I always run my B20b engines on Shell V max (UK 99ron octane)...these engines would have originally been run on 100 octane...on my last Amazon I experimented with fuel...and V-Max was the best...even BP Ultimate wasn't that great.

Be aware that you can't compare the old ron ratings with the modern ones. Somewhere in the early seventies they changed the way ron is measured. So the ron 100 from the sixties manuals is about ron 97-98 today.
The USA use a different rating system, MON instead of RON. The usa's mon91 is euro's ron95, it's rated about 4-5 points lower than the euro.

[scapa]

You cannot beat NGK, superb plugs

[amaz'in]

Very true B20F...

I also figure many B/E heads may have had a skim by now..especially such as mine..which went in for Unleadeed work..so raising the compression a smidge more...

So I just run a high Octane fuel...and adding Tetraboost is way over the top...but since the engine was totally re-built less than 5000 miles ago..I want to look after it...adding lead should make it run a bit smoother..and I figure help cool Valves etc....

I currently have some Splitfire plugs in..which work really nicely...but will compare back to NGKBP6HS then to a 7HS in the next few weeks....I get a very slight run on with Splitfires..so will try 6's first..then up to the 7's..

J

[B20F]

I currently have some Splitfire plugs in..which work really nicely...but will compare back to NGKBP6HS then to a 7HS in the next few weeks....I get a very slight run on with Splitfires..so will try 6's first..then up to the 7's..

The 6 is recommended for the low comp. B20F and the 7 for the high compr.
B20E, but you are probably aware of that! I always stick to NGK, and have used them in all of my cars.

[amaz'in]

Fitted the 7's this afternoon...runs just as sweetly as before...with Zero run on. (so far) so look's like the perfect plug for my engine....

With the 6 it ran on maybe 25% of the time...and as I found out when I purchased the car...the 8's weere way too cold......

It's 7's from now on for me...just as well I bought a small box of em'...lucky gamble..

It would seem they are not a common use plug, none of my local motor factors had them (all were order in) yet they all had the 6's.

J

[deathrider311271]

this might seem like a daft question, but here goes, u said u had your engine rebuilt so why didnt u get harder seats put in at the same time? is this not possible with this engine? only asking out of curiosity as this is what i did to my original capri engine and that ran fine on regular 95 Ron unleaded without any aditives needed, in fact i sold that engine to my mate 5 years ago and it has just clocked 100k on the engine no problem at all.

[amaz'in]

Hi Deathrider,

You will see in post #2 I did indeed mention it had an Unleaded head when it was re-built.

Sure it will run fine becuase of this on the unleaded fuel....but it will run nicer...and cleaner with some lead..better valve cooling etc too....

Also..if it was a single carb...95 would be fine..anything would..but in a higher compression B20b twin carb..higher octane is better.

Just a bit sick that the previous owners who spent over £3k on the re-build didn't opt for an additional £400 for a Gas flowed head whilst they were at it?? yet they opted for a fast road cam..and even an Engine block heater etc?

J

[deathrider311271]

ah ok its always handy to know these things lol, the guy who had the engine built certainly made some strange choices in what he had done and didnt, i personally cant see the point of a sports cam with no head work done it kind of defeats the object of what u r trying to do. just so u know i tried both options lol and found out the hard way.

Anyway thanks for your reply

simon