Spark plugs?

[totorote27]

I was wondering if all 2tc/3tc use the same spark plugs. The reason I ask Is because I got two engines, one running and one not, and they have different spark plugs. The threads on one are about half the length of the threads on the other. The non running engine has the longer threads and the spark plug just barely enters into the combustion chamber. To me this seems correct. When I thread the shorter one in it does not enter the combustion chamber. It is about a 1/4" shy of entering in the combustion chamber. This is an issue of concern for me because I have the shorter ones in the running engine and I am having troubles tuning it. It wil run rich/stoich for a little while then it runs lean. Could the spark plugs cause this?

[VinceG2]

According to the various repair manuals I have from Toyota themselves, the 2T-C amd 3T-C engines came with:

W16EX - U,W16EP (ND [Nippon Denso]
BP5EA - L,BP5WA - L (NGK)

You can see a list of replacements for BP5EA see here:

http://www.sparkplug-crossreference.com ... BP5EA-L-11


Gap should be 28 to 31, usually 31 is given in the books.

[totorote27]

I order plugs from BRD racing and got autolite AR 13. (They seem to short). He told me to set the gap on those at 40. Does it make it difference if it's a race engine vs. stock engine

[baldo]

This is something you dont want to mess with unless you are tuning the engine and know what you are doing! There are many different plugs you can use. Short, long, colder and hotter. Do you think all those are the same? Brd has some great parts but you need to know exactly what you need. In my experience they will give you a spiel and sell you something you need. But its like they dont like to deal with people or take the time to have a great experience with them. So I suggest to go to the parts store and get spark plugs for your car. Something that has me , does it make a difference if its a race engine or stock engine? Do you really think you can swap racing engine parts with a stock engine and work fine?
I guess you have a stock engine with two different plugs. Have you tried to put the long ones on yet? I would start fresh and get new ones. Stock new ones. Then mess with the carb, sounds like the chokes when they open are messing up your tuning.

[VinceG2]

The autolite 13s are with a 0.460 in. reach, while the plugs for the stock engine are with the longer .750 in. reach. Use the longer plugs in your stock engine. The 13s are for a racing engine, and have no resistor, while stock spark plugs have the resistor on them. If you plan to stick with Autolite, use Autolite 64s, they have the correct reach for the stock engine.

I'm sure someone else can correct me, but I believe you use bigger gap for more powerful coils, so for stock, ~31 is the normal gap.

[totorote27]

here is a description of the engine just to give you guys an idea of what im working with:

i have built a 1972 te27 rally car with engine specs as follows:
44mm intake valves/39mm exhaust valves
double valve springs
norris 368 cam(490 lift/268 duration)
eagle connecting rods
race prepped 3tc crank
87mm wiseco pistons
distributor is locked(no mechanical or vacuum advance) with timing set at 28* BTDC
MSD 6al
44mm mikuni sidedrafts w/mikuni manifold

i am new to engine building/tuning so i will have questions that more experienced people can help out with and save me the frustration and headache of trial and error with simple things that i am still unclear about.

VinceG2: in your opinion it is ok for the spark plug to not protrude into the combustion chamber(autolite AR 13)? what will happen to stock plugs/and how will it effect engine performance in the above engine

[totorote27]

another question. does anybody know if there is any variation in the length of the treaded hole for sparkplugs in the 2tc/3tc heads?