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Posted by: Eddie914 Mar 15 2004, 05:29 PM

What spark plugs should we use in a 2.7 with 40 IDA Webers, stock ignition, and Bursch headers and exhaust?

Thanks in advance

Eddie

'71 914/6 2.7

Posted by: J P Stein Mar 15 2004, 07:44 PM

What compression/pistons ya gots?
Cam?

Posted by: weird_looking_cactus Mar 15 2004, 09:03 PM

I would try the borsch platinum 4+ spark plugs suppose to be the best you can buy! But Im not sure how your suppose to gap them. Cause they have 4 little things you have to gap instead of one.

Posted by: 914to6 Mar 15 2004, 10:18 PM

What do you (we) have in there now, and how do they look?

That would tell you (us) a lot about the replacement plug's requirements.

Walt Suman
ps, I meant to peek last week.

Posted by: ArtechnikA Mar 15 2004, 10:26 PM

the Bosch '+4' is 100% snake oil although they do give you a good advertising spiel, as all the very best snake oil does.

i really like my Denso Iridium, but they're pricey.

a nice NGK 6 or 7 or Bosch SilverTip - say a WR7DS - would be fine.

when you say 'stock' ignition, what does that mean, exactly. 'stock' came with the car? 'stock' came with the engine ? which ?

Posted by: Eddie914 Mar 15 2004, 10:32 PM

JP ...

Question: What compression/pistons ya gots?

Answer: Some/six



Question: Cam?

Answer: two


The previous owner performed the conversion years ago with a 1977 2.7 motor he purchased complete with the Webers from a salvage yard. He was note sure of the specs.

I have yet to do a compression test or pull the valve covers to look for part numbers on the cams. I suspect that if it still has it's stock pistons (8.5:1 IIRC) compression should be about 170psi. I have run everything from regular unleaded to premium unleaded and have never noticed any predetonation (as if I could over the Weber induction music).

It revs freely and and seems to have a very even powerband right up to the rev limiter at 6500rpm. The engine seems to load up a bit under 3,000 rpm under light throttle application. The smooth idle does not seem to indicate aggressive cams. Above 3,000 it runs beautifully. I'm guessing the carbs need a rebuild and the plugs are fouled. I've cleaned the idle jets three or four times since we got the car in January to cure the backfiring. We have run all of the old gas out of the tank now and the idle has cleared up but it's not very happy under 3,000 rpm.

A borescope would be a handy tool to check out the piston crowns ... unfortunately I don't happen to have one.

Thanks again.

Eddie

Posted by: Eddie914 Mar 16 2004, 12:14 AM

Only had time to pull one plug.

Bosch W5DC

Gapped @ 0.030"

Very little wear.

Not fouled

Posted by: J P Stein Mar 16 2004, 02:04 AM

I like NGK. For a stockish motor, BP5ES or BP6ES.....the latter is colder. I run 7s but 8s would be better(safer) for the track.

There is a fix for the under 3000 rpm Weber blues

The car looks gud, enjoy......but watch the oil temps.

Posted by: ChrisReale Mar 16 2004, 02:40 AM

Firts name fuel, last name injection?

Posted by: J P Stein Mar 16 2004, 04:46 AM

Dude, I'm a carb guy.

Posted by: joea9146 Mar 16 2004, 05:01 AM

Like JP said go with the plain old NGK plugs, I use the BP6ES.

What are the plugs fouled with ... is it Gas or Oil.

I also run an MSD 6AL Ignition

Posted by: ArtechnikA Mar 16 2004, 06:32 AM

a Bosch 5 is pretty cold, you could probably get away with an NGK 8 (i run 7's in my street 2,2E but i have a set of 8's for track use... donno what kind of compression ratio you're running (-NOT- the same as compression test psi numbers...) but stock 2,7's run less than the old little motors used to...

but if you like Bosch and that heat range is working for you, and you're looking for a small upgrade, you might consider going to the SilverTip ('DS' instead of 'DC' suffix).

0,030" is basically the stock gap, maybe a little on the wide side; sounds good to me. (i run 0,044" with my Crane HI-6 (Multiple-Spark))

the short answer on plugs - especially heat ranges, is 'ask your engine, it'll tell you what it needs' and it sounds like yours is pretty happy with what it's got.

i fibbed a bit in the first paragraph. i don't actually run NGK's right now, although i do have a set of their 'Double Platinum' (which means Pt on the ground and + electrode, NOT dual-grounds...) 8's for track use. right now i'm using the finewire Denso Iridium plugs and i think they're working for me. getting MFI to run clean is a challenge and i like what i'm seeing. in many ways, carbed track cars are easier to tune for ...