Johnny Haywire

BP5ES or BP6ES - which is better for my set-up?

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Hey guys,

I know it's been a little while since I've posted. The car is here but still in winter storage out in the burbs, so I only get over there every couple of weeks for a little while since the garage isn't heated and it's 40 miles away (better than 2,200, right?). I'll be bringing it up to my place once the salt has been washed off the roads and the temps come up a little.

So, the plan is to work on a few small things on Saturday and I wanted to throw new spark plugs in while I was there and take it for a spin. I know BP5ES and BP6ES are the general recommendations for 2002 2.0 liter engines and I always use NGK, but I'm not sure which heat range I should go with. Here's what I know about the engine:

 

1968 2.0 liter with stock exhaust manifold, converted to 12v w/ alternator

1974 E12 head (I'm assuming stock)

Top end redone about 95K ago (chassis has 155k on it, not really sure about the bottom end)

Weber 32/36 carb with stock BMW intake manifold (late '72 and on according to the paperwork from Seven Flags who sold the PO the carb/manifold kit) with stock BMW snorkel air intake.

Ignition seems stock Bosch but with an MSD-5 box.

Records indicate jets being done in the '80s on the carb. Car was from the Bay Area and is now in Chicago, so not a ton of altitude difference there.

 

Would you choose BP5ES or BP6ES for this application?

 

- Paul

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Sounds like your engine is pretty stock; so long as it hasn't developed a thirst for oil, BP6ES plugs will be fine.  They're the closest in heat range to the OEM Bosch plugs the factory fitted when new.

 

mike

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Stock compression ratio?  Are you burning Premium (91) or Regular (87) gas?

I ran BP6ES plugs with Premium gas in my stock '76 (w/ E12 head) and always had sooty/oily plugs.

Switched to hotter BP5ES and Regular gas ......and now it runs better than ever and the plugs are picture perfect after 1,000 miles.

Improved fuel economy too.... now getting 26-28 mpg.

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Buy both, run both. To a certain extent every engine is different here so you need to try them. The right heat range is the one that allows the plug to heat up enough to burn off deposits and stay clean but not so hot that you get pre-ignition. 

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The plug you use will depend on the engine condition. If your car burns oil, maybe rings not sealing then you may want a hotter plug which burns the oil off the plugs more. But that will heat the head up more and may cause other issues down the road like a hole in a piston or burned valves.  If the engine is running well go with the BP6ES. 

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I don't know if she burns oil yet, only drove for 3 miles in the dark the night I got it. I believe the compression ratio is stock. I have the option to run 87, 89 or 93 octane here, though I prefer to run 87 whenever possible for cost reasons. I'll get both sets and try them out with different grades to see what it likes best.

 

Thinking I'll do a half tank of regular (87) and swap from hotter to cooler at 1/4 tank. Once that runs out, I'll do a half tank of premium and swap back up to the hotter at a 1/4.

 

Results to come!

 

Thanks again for all the input, guys. I really do appreciate it. Cannot wait for this salt to wash away so I can start driving this thing.

 

 

 

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Question...what’s in it now?  I’d replace with that and then change it if needs to be changed. Don’t change it unless it needs t be changed is my motto. 

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Johnny Haywire,

 

I didn't mean to say that a simple plug heat range change or using 87 vs 91 gas is the cure-all.

I started my quest for a smooth idle, peppy acceleration, clean oil, clean plugs and decent gas mileage last year.

I had to get rid of the slop in the distributor, replace the throttle shaft bearings (vacuum leak), power valve, accelerator pump diaphragm , and plastic float (replaced with brass) on my Weber 32/36.

Once this was done, then I spent time fiddling with the timing and vacuum advance and the electric choke setting.

 I went to a BP5ES plug (slightly hotter than the BP6) and switched to 87 octane gas as another step toward reaching my goals.

This last step reduced the soot on the plugs and in the tail pipe, and made the engine run much smoother.

Our cars are 42+ years old, and were designed to run on leaded gas. This was very different chemistry from the stuff we get at the pump today.

 

John

 

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Thanks for the info, John. I know it's not the cure-all, but it's great info to have in my back pocket as I go through the car. I really do appreciate it, and it will really help me with getting this one running at its best. It will get a full tune-up and going over once it is in my garage. I'm not even sure what's in it now in terms of plugs. Despite owning it since late November and taking delivery in late January, I've only spent about 2 or 3 hours with the car (I have a safe (but not local) place to store it until winter lets up, so I went with it). Once I have it on hand (late March), I'm going whole hog on this thing.

 

It's killing me to not have the car nearby. It would be at least half prepped by now if I did.

 

I think I can safely say that it may have plugs in it from 1999, which is probably good because they are what the long-term owner always ran in it (1970-2000), and the car has only had 4,000 miles put on it since 2004.

 

In 2000, it was sold to a guy who did nothing to it but store it in the sun and kill the seats and paint. My friend bought it 2004 and she is not mechanically inclined, so all service was done by random shops, so it was kept running, but maybe not the way that we would have preferred. In fact, I know it was not the way we'd have preferred based on some receipts in the records. After the year 2000, no one even knew it had a 2.0 liter until after I purchased it and looked through the records and saw this fact (it's a '67 1600-2 with an updated engine).

 

So, kind of flying blind here for the time being. But coming full circle, you raise an excellent point and I will put in whatever plugs are currently in there and see how she behaves. When I first drove it, it ran well and pulled pretty hard. But when I started it up a few weeks later, it didn't want to start and ran like $hit until it warmed up. But that could be due to a number of reasons (31 degrees F, electric choke setting as you mentioned, and I probably flooded it when trying to start it, etc.).

 

I'll post pics of what I find on Saturday. Should be interesting.

 

 

 

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2 hours ago, John76 said:

Johnny Haywire,

 

I didn't mean to say that a simple plug heat range change or using 87 vs 91 gas is the cure-all.

I started my quest for a smooth idle, peppy acceleration, clean oil, clean plugs and decent gas mileage last year.

I had to get rid of the slop in the distributor, replace the throttle shaft bearings (vacuum leak), power valve, accelerator pump diaphragm , and plastic float (replaced with brass) on my Weber 32/36.

Once this was done, then I spent time fiddling with the timing and vacuum advance and the electric choke setting.

 I went to a BP5ES plug (slightly hotter than the BP6) and switched to 87 octane gas as another step toward reaching my goals.

This last step reduced the soot on the plugs and in the tail pipe, and made the engine run much smoother.

Our cars are 42+ years old, and were designed to run on leaded gas. This was very different chemistry from the stuff we get at the pump today.

 

John

 

 

Thats good info, your first post kinda implied he should just switch gas and get a hotter plug when that COULD actually damage his engine if the plug is too hot for it and it pre detonates.  I ran a hotter plug in mine for a while to test it just to see and mine was burning a lot of oil.  Eventually after a rebuild, I'm back to the "normal" plug.

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9 hours ago, Johnny Haywire said:

It's killing me to not have the car nearby. It would be at least half prepped by now if I did.

 

I feel your pain... I sold my house (with garage) a couple years back and bought a town home with no garage... other factors caused that decision. But for the last two years my car has been in a friend's garage across town, in an expensive storage unit when that friend moved, then in Charlotte for a year at my brothers when we were rebuilding the motor. Now it is back in Raleigh at another friends garage and I get to her usually every other weekend.

 

But I won't complain after 9 years of being off the road and "under construction", she finally is drivable :)

 

Randy 

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8 hours ago, worzella said:

 

I feel your pain... I sold my house (with garage) a couple years back and bought a town home with no garage... other factors caused that decision. But for the last two years my car has been in a friend's garage across town, in an expensive storage unit when that friend moved, then in Charlotte for a year at my brothers when we were rebuilding the motor. Now it is back in Raleigh at another friends garage and I get to her usually every other weekend.

 

But I won't complain after 9 years of being off the road and "under construction", she finally is drivable :)

 

Randy 

Thanks, Randy. Counting the days until I get it up here!

 

Can you post a pic of your car? I tried a search but didn't come up with anything.

 

- Paul

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On 2/27/2018 at 8:54 PM, Johnny Haywire said:

But coming full circle, you raise an excellent point and I will put in whatever plugs are currently in there and see how she behaves.

 

Suggest posting a photo of your existing plugs as they came out ... a look at the threads can offer some information about whether you’ve got an appropriate plug. -KB

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Recent.. needs a bath and still working out a few last gremlins.. A million more pix on my tag line Shutterfly account.

 

IMG_6032.JPG.08e8e5c600d417c037f047cdc86a7ffd.JPG

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15 hours ago, kbmb02 said:

 

Suggest posting a photo of your existing plugs as they came out ... a look at the threads can offer some information about whether you’ve got an appropriate plug. -KB

 

I'll make sure to post some pics of what comes out of there. Heading over on Saturday and it's supposed to be clear, chilly, but clear : )

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