Spark plugs - Platinum

Just taking a survey as to what porsche owners think about Platinum plugs for our engines. I have a turbo Conquest also and have heard horror stories about platinum plugs "blowing out" under high boost to failing center electrodes... I have a 993, with high compression ratio ( 11 - 1 ), would using the Bosch +4 Platinum plugs be ok or would it be too much for platinum plugs. Other reason for looking towards Platinum is because changing plugs are nearly impossible on the 993's, 2 plugs per cylinder.

George

I have tried the bosch +4 in my 85 and was not impressed at all. Lost power everywere and got bad gas millage. I would use the recommended plugs for your application.
Bosch also will give you your money back if you are not satisfied.
DRD 85 Carrera

Just use the plugs that P. recommends for application (Mainly for the heat range purposes).
FWIW I heard once that there has not been a "truely" significant change to spark plug technology in the past 30-40 years and I have to agree with it.
It takes one good spark to ignite the fuel and once it is lit all multiple electrodes, V-grooves, platinum this or that, and all the other ridiculous/stupid things that they want to sell you (Marketing) for $5.00+ per plug don't really do much.
Electricty will still go the shortest path (and the one of least resistance). It will not blast across 4 electrodes fill "V" gaps or grooves (it will go to the closest one and always will).
One last thing on this, If there was one type of plug that gave magic milage increases or hp/tq. numbers that were significantly better than the others, EVERY brand new car that every manufacturer sold would come from the factory with that Magical set of plugs.

IMHO a quality set of plugs need not cost a dinner out with your wife/girlfriend.

s

Well, would you believe 55+ years on the multiple ground electrode plugs? They were in use in piston-engine aircraft during World War II, for certain in Allied aircraft, and most likely the 'other' side too, considering the lack of secrecy!!! And as far as 'advances' in ignition systems go, I suspect the latest processor-controlled engines operate a bit longer, and over a wider range of operating conditions, but do not really improve the specific output available from a pound of gasoline on a multi-valve magneto-equipped engine from the late 1930's through the '50's!!! Me thinks the desmodromic valve gear and cam timing of the '55 Mercedes 300SLR would work pretty well on any Motronic-controlled engine for which you care to adapt it! REAL 'advances' in engine technology has been very scarce over the past half-century!

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Warren Hall
1973 911S Targa

Warren, I agree that aviation gave us allot of good stuff or the car market stole from them (nitrous, roller cams, magnitos ..etc.)Hell, Roller cams were used in round engines.

The electronic ignitions have been up graded for reliability/precision and coils have hire outputs for more current/voltage at the plug now.

I may have misunderstood your post ,sorry, but I take it that you agree that just plugs will not make your car significantly better.?

s

No, I don't really think any of the 'gimmicks' the hypesters keep bragging about make any significant improvement in power, economy, or emmisions ... and I've used the same arguement that any 'magic' plug would be instantly adopted by major mfrs, if even 1 mpg improvement could be documented! The one thing platinum electrodes or multiple ground electrodes MAY do is possibly extend the lifetime, or reduce the tendency to foul over a 'conventional' plug, but those are hardly worth doubling or tripling the pricetag!!!

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Warren Hall
1973 911S Targa

Again, I total agree with ya. That's what I thought you meant.

s

I was told (by whom? I don't remember - how is that for a reliable source!) that for many new cars the labour cost associated with a spark plug change makes 60k mile platinum tipped spark plugs a cost effective option.

Specifically, I think I was told this in relation to a Subaru 2.0 litre turbo motor, and it required removal of a whole lot of ancilliaries to get at them.

Generally, if they do last 60k miles without maintenance, then they would be cost effective assuming you weren't going to take out the plugs for any other reason.

It doesn't apply to me though, and I expect it doesn't apply to the majority of Porsche owners.

Cam

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Cameron Baudinet
1975 911S

That sounds like a 'bean counter' (an accountant) that knows NOTHING about engines, or service practices, or how line mechanics actually work in the shops ... worked out that justification on paper!!! I would wager a large amount that not a single documented case can be found of a 911 going 60K miles on the original set of plugs! Not that 911's are particularly hard on sparkplugs, either, there are many cars worse! Not a gambler, here, so nobody needs to take it seriously, but you get my point, I think!

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Warren Hall
1973 911S Targa

I'm not a gambler either, and if I were I'd gamble with someone else. but I would not be surprized at such a story. I've heard (probably that same unimpeachable source cited by CamB) that a spark plug can last a LONG time if the engine is tuned and the plug is cleaned periodically. some folks (perhaps not Porshce owners) do this and change a plut only if it fouls, which they maintain is rare in motors not burning oil.

That being said, I change mine, to factory specs, probably once a year.

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'83 SC

I haven't had my car a year yet but soon after the purchase had a need to change wires because one was broken. I decided to change plugs at the same time because of questionable maintenance. I went through two different american made plug manufacturers with constant fouling. I finally decided to spend the extra money and buy Beru from the dealer. I have had no problems with them after. They burn a little hotter but when I have brain fade and flood the engine due to not getting the cold throttle quite right they clean themselves off very well. I have been very happy with them.

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John Birkett
72'T Targa

John, I hope you kept those old, OEM wires ... because they CAN be refurbished, broken connectors can be replaced!

The black neoprene, copper-core wire can be replaced by bulk, premium silicone 7 mm wire with stainless steel core (virtually indestructible) for many more years of useful life! Both 'ends' of each wire unscrew from the wire, counter-clockwise ... clean the ends with isopropyl alcohol, soak, the rub & brush off all of the engine grime with an old toothbrush ... magic! Like-new connector in your hands!!! Replace the wire and you have a like-new set of spark plug wires in hand! Or, a valuable set of 'spares' if you happened to buy a replacement set of OEM wires. If you bought aftermarket wire set, you have my sympathy ... they won't last more than a year or two!!!

One other thing ... those 'air seals' on the BERU angled connector are none other than OEM VW Type 1 parts ... you can't get them from VW any more ... but, aftermarket foreign car parts stores carry the original design, Brazilian-made 111.905.449 part. When you find the Brazilian, original designed part, buy 20 or so, and keep them in your car with the tool kit! Check them frequently in hot weather ... just as often as you check your tires!!! If the seal is shriveled-up and not sealing properly ... REPLACE IT!!!

The VW ...449A part WILL NOT WORK on 911 spark plug connectors!!!

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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 05-20-2000).]

[This message has been edited by Early_S_Man (edited 05-20-2000).]

Back to the original post, I put Bosch +4 plugs in my car shortly after purchasing. The PO has some corrosion problems on the spark plug tips and the connectors were not making a positive connection. After installing the new plugs, the power and idleing seemed improved. Granted, this was comparing them to possibly inferior previous plugs. Bosch has a good reputation for making quality products. I do know that the replacement interval is extended with these plugs, so for the extra few bucks I would say go ahead.

Warren,
Why is the seal so important around the plug insert?

That seal around the spark plug connector is important because the air channels in the head are interupted by the plug, and any air leakage out into the engine compartment means two things: 1. the air did NOT flow down past the center of the head and down and out the bottom of the cooling fins on the cylinder head! 2. The air escaping at the valve cover is 'preheated' and going back into the engine compartment to be ingested by either air cleaner intake, or alternator mounted cooling fan ... and preheated intake air is the last thing a 911 engine needs in the summer!!!

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Warren Hall
1973 911S Targa

I wasn't very clear on the wire replacement. I replaced them with OEM and replaced the plugs with Beru.
Regards,

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John Birkett
72'T Targa

[ohecht]

Is there any disadvantage, other than price, in using a platinum plug of the same make and heat range?

In other words, is a WR5DP the same as a WR5D in an SC, other than the materials in the plug, the price, and the expected wear characteristics?

My engine plate calls for the WR5D, so I want to make sure there is no harm in using WR5DPs. I'm not sure if platinum plugs were prevalent in '82.

Olivier

[Superman]

As I mentioned in the other thread, some trusted VW mechanics I've known have expressed a preference for the copper. But no, the platinum version won't hurt your engine.

[feelyx]

I ignited some gas today with my arc welder... so I guess the multi spark theory does work

Tim in Sac

[howie944]

Tim,

So that's what all those sirens were I heard today in SAC!