having issues with this spark plug

[Killacortes]

So a little background on the car. Its a 885 head on a 2.7l bottom end. The head i used was from a boosted m20 with BPR8ES NGK plugs in them. The car would start right up but felt like it was missing.

Now knowing that these plugs are not for an NA m20 I went out and bought autolite copper core 64 plugs. With these plugs the car would not start at all. I would constantly get fuel soaked plugs.

Switching back to the BPR8ES NGK plugs car would start right up again.

Not sure whats going on here? Are the autolite's also the wrong plug?

[Hooffenstein HD]

You want BP5ES, maybe BP6ES.

[Killacortes]

okay ill give that a shot

[Hooffenstein HD]

okay ill give that a shot

I believe BP5ES, or ZGR5A is standard for an NA M20. Probably best for your application since you're running an #885 head.

It's once you start raising the compression that you may need the slightly colder BP6ES. I've heard they have sorted out a slight misfire with #731 strokers.

[digger]

BPR5ES/ZGR5A for low com NA and BPR6ES for a higher comp NA

[Killacortes]

It is a lower comp. Thanks for the advice guys

[Hooffenstein HD]

It is a lower comp. Thanks for the advice guys

Sorry, digger is right. I've quoted the correct heat range but forgot about the R for resistor. Non resistor plugs like the BP5ES are for L-Jet M20's without electronic ignition.

[Killacortes]

Not sure what's going in here but I went out and tried the BPR5ES plugs and they will not start the car. Seems like only the BPR8ES plugs will work which is a colder plug.

More background on the engine
885 head
Dual pattern cam from bummer heads
Oversized eccentrics
HD rocker arms
Vac dual valve springs
Adjustable cam gear from bummer heads
Vac valve keepers

[Killacortes]

Could a bad cps cause this problem?

[digger]

i doubt the CPS would only begin to be problematic with a certain plug heat range

[Killacortes]

That's what I'm thinking too. I did a spark test and both plugs came in very weak. Both the cold plug and the oem.
Cap and rotor are brand new bosch replacements
Plug wires are in good shape from bremi

[digger]

coil?

[Killacortes]

I swapped the coil out of my running eta. And same problems persisted.

[Killacortes]

Well realized what was going on here. The plugs I bought did not come pre gapped. They were around .04 and the colder plugs were the right gap. So I re called all of them and boom starts right up. What a stupid mistake lol