Thread: L67 engine block

I don't know how fast a l67 is with my setup... But this thing pulls hard and will screech the tires at 40 around 3/4 throttle (only boosting about 6lbs). Is that fairly normal or does that sound like the engine is putting out a little more power than normal (as the higher compression L36 will do with less boost).

It's real... If I take the s/c belt off I can beat on it with zero KR. And as long as I don't let the boost get over 5-6lbs the KR is at or close to zero. I'm seriously considering buying a 4.0 pulley for it... lol

Are you using an mps system or press on?

I have ZZP's MPS

No catalytic converter. I have headers with 3" dp.
I'll try checking the compression on it sometime. I'm also thinking about closing the gap on my plugs a little... maybe .045 or so. They are gaped at .053 right now. Maybe that will help...

Originally Posted by rolyat

Now has new fuel pump assembly and a known good ICM... same problem.

Is there an actual compression difference between a L36 with the L67 top end components? I know compression ratios are different, but what about the actual compression? Will it be higher? I really want to know if my car has an L36 lower end... I saw that a bolt was missing out of the transmission bell housing, which leads me to believe either the engine or trans was pulled at some time...

CC's are both 64 cc.

The only difference in the bottom end are the rods, pistons, pins, balancer, flexplate, and cam gear.

Originally Posted by Rico

A couple things to check IMO:

Catalytic convertor clogged?
DP 3"?
Compression ratio

I think you are on to something with the compression ratio. The L36 should be about 160psi and the L67/L32 should be much lower. Like the other guys said, have someone with tuning experience take a look at it if it appears to have the lower compression pistons.

You cannot check compression ratio short of boroscoping both types of blocks or CC'ing the pistons.

The cam gear in a N/A block is 1* advanced. Not exactly detectable.

Compression test values are quite a useless figure considering ring wear and valve/seat wear would negate any differences.

Originally Posted by rolyat

I have ZZP's MPS

No catalytic converter. I have headers with 3" dp.
I'll try checking the compression on it sometime. I'm also thinking about closing the gap on my plugs a little... maybe .045 or so. They are gaped at .053 right now. Maybe that will help...

Closing the gap isn't the best way to solve this.

Have a known good ICM you can swap in?

When I first top swapped my car wouldnt run KR free past 2 psi until I swapped out the ICM for another unit.

My compression tester wasn't holding the pressure, but it looked like the needle was bumping up to 145psi and maybe a little higher.

I just swapped the ICM and it made no difference.

I took off my ZZP plug wires and put in my brothers ZZP wires. It got rid of all the misfiring and gave me a noticeable power gain... due to the fact that I can finally put the pedal on the floor! There is still some knock (around 5*) at full throttle and higher rpm's. I'm thinking the ZZP plug wires are crap in general and I'll get some OEM replacements. I guess I just went from one bad set of wires to another and another lol. Maybe that will get rid of all the KR.

I guess I missed the memo... lol

Does anyone have any recommended quality plug wires that aren't overpriced and will get the job done? Accel, Walker, ACdelco?

Advance, buy a lifetime set of autolites... Done

Were talking about the sc motors not the na

Android Fire

I went to oreillys and bought the lifetime Borg Warner's. Ready to get these sh**ty ZZP wires off my car and soak them in some gasoline... then watch them burn!!! I'll buy my brother a new set too. Lol

The new wires helped. I can go full throttle without any misfiring and the KR stays between 0-4* so it was definitely an improvement! I'd love for it to stay at zero, but this is the best it has been since I've owned the car so I can't complain too much.