LZ Losing power and Overheating

[metalmonkey47]

So here goes nothing: 

 

LZ22

 

Z20 Block

Z20S Rods (long rods)

Forged 86mm Pistons

A87 Peanut head w/ Z valves, .475 Cam, 1 5/8 intake ports Compression Ratio comes out around 9.4:1

Header w/ 2.25 exhaust

ARP Head/Main studs and rod bolts

Matchbox dizzy

Running a port matched U67 intake with EGR ports welded up and a 32/36 with .140 main/secondary fuel jets

160 degree T-stat

 

 

Noticed over the last few days I've been losing a little power, in fact I don't feel like I'm doing much better then my 52HP L20B anymore. Plenty of torque, not much power anymore.

 

In addition I've noticed today that on long drives after driving the truck under load at highway speeds it starts to overheat. Pulled the t-stat hoping it was the problem, but no good. Radiator hose is in good shape, radiator is fresh and clean as is the block.

 

 

I'm thinking I may be running super lean, but I'm not getting any pinging. I retarded the timing down to about 5 degrees to see if advance might have been the issue, but it made little to no difference, but made a little bit better power.

 

Idling the engine seems to cool itself efficiently. I'm running a 14'' electric fan and an engine mounted fan. No coolant in the oil or vice versa, but I'm going to compression test it later anyways, since it's only got about 300 miles on it so far after the first break in oil change... it runs good, and consistent but is a HUGE loss in the power department. I know my carb/spacer aren't very good for the motor to begin with, but this thing is BUILT and isn't making enough power to compete with a stock L20B. 

 

 

Feedback?? 

[kelowg]

check your plugs, try moving advance back up above 5 degrees. jetting does sound a little lean, my lz21 has 150 pri/ 155-160 sec. but mine pings really bad at anything over 5 degrees. 

[Rollover_Red]

compression check will deff help.

 

but this happened as you were breaking it in? like when you first got it running, did it have power...?

[Rollover_Red]

also, did you drill the block and head gasket to fit the Z bottom end?

[metalmonkey47]

check your plugs, try moving advance back up above 5 degrees. jetting does sound a little lean, my lz21 has 150 pri/ 155-160 sec. but mine pings really bad at anything over 5 degrees.

 

 

 

Yeah, I'm gonna go drill a spare jet tonight and open my secondary a bit. I've had the timing up to about 14 degrees and.never pinged. Even under heavy load running lean which is weird to.me. I'm gonna check the plugs in a short bit.

 

 

compression check will deff help.

 

but this happened as you were breaking it in? like when you first got it running, did it have power...?

  

 

also, did you drill the block and head gasket to fit the Z bottom end?

 

It made decent power before, not as much as I feel like it should have but the weber is a huge turn down. I also have a tall spacer that probably isn't helping.

 

The Z20 matches L20 perfect gasket perfectly so no drilling is needed when using an L timing.cover

[Stupid_fast]

Didn't read any of the thread.

 

 

32/36 on 2.2 liter? running lean.  140 jets are about for a stock or cammed 2 liter!!

 

 

Have you tuned the idle circuit yet?  DGV tuning starts with the idle jets, main jets, then air jets.  Follow this or you will never get it tuned right. 

 

try  main jets at 160/150 or so.  Look up DGV tuning, main should be bigger than secondary. 

 

 

Rich is better than blowing something up running lean.

[metalmonkey47]

I've got the idle circuit done, Ive got a spare jet so I'm gonna try and find a bit to.match close to a.160 and see how that goes.

 

Thanks for the information. I've been trying to set something up with some SUs or a single DCOE but I.need this thing to go okay for now. I really don't need to blow up any expensive parts!

 

I have no idea what the air jets are. Any idea on a proper size to go with those jets??

[Stupid_fast]

Did you up the idle jet already ? should be at least a 65 or 70 on that 2.2...

 

drop a 160, it might sputter onto the secondary but just worry about the primary right now.  could even just 150/150 or 160/160 don't touch the air jets and call it good.  Stock airs should be 170/160.

Just make it more rich, if it doesn't run perfect that's fine as long as its not lean like it is now. 

[Xnke]

Stupid question...Have you done a valve adjustment?

 

On a new motor...valve adjustment every 100 miles till they quit closing up. They WILL be closing up! On a fresh head, the valve seats and valves will be wearing in much much much faster than the cam and rocker interface...valve wear is rapid and valve lash will close up during the initial mating period, about 1500 miles...then flattens off for the "maintenance period", then near end of life the valve lash will start to open up again.

 

Do a valve adjustment, then fiddle with the carb.

[Z-train]

Stupid question...Have you done a valve adjustment?

 

On a new motor...valve adjustment every 100 miles till they quit closing up. They WILL be closing up! On a fresh head, the valve seats and valves will be wearing in much much much faster than the cam and rocker interface...valve wear is rapid and valve lash will close up during the initial mating period, about 1500 miles...then flattens off for the "maintenance period", then near end of life the valve lash will start to open up again.

 

Do a valve adjustment, then fiddle with the carb.

I've been running solids in everything from Datsuns to Ram AIrIV Pontiacs to 427 Side-oilers to 426HEMIs for the past 40 years.And i've never done what you're recommmending.And more important-never even heard of it.

[620Turbo4X4]

What heat range plugs are you using?

 

With that compression I would be running a BP8ES, a 9, or the maybe even the non projected tip B8ES if you drive it hard. Having that huge glowing ground electrode with the projected "BP" type, and having too hot of plug could be acting like a "glow plug" in a diesel, and igniting the mixture before the plug fires. That might explain why your not seeing much difference by changing the timing?

 

No more than 8-10 degrees advance @ 650 RPM, I would also add a additional lightweight spring to one of the mechanical weights in the distributer so it will advance later and at a higher RPM and reduce slop. Plus, you'll want to limit the travel and the amount of the vacuum advance approximately in half to stop the part throttle ping you'll have by using a vacuum advance that was designed to have a EGR system. All smog distributers will have too much vacuum advance when used without the EGR valve. I limited mine by loosing the screws and rotating the base plate to compress the diaphragm half way, then tightened screws back down and readjust timing. Easy fix. 

 

 

I noticed todays gas doesn't really ping like the gas of the older days. While recently trying to time my engine by the old "listen for the ping and back it off a bit method" did not work for me. My engine would simply run hot, loose power, and not till I reached 20 degrees did I hear pinging, then It actually began to cut out with that much advance. I also noticed that when I installed my high compression engine I had a full tank of regular in the truck. instead of draining it and all that I simply added a bottle of 108 to the tank. Oddly, immediately after using it all up and filling with so called Super, I noticed bit less power???

 

I'm running a 50 idle 150 primary 160 secondary in my weber. BP8ES Plugs run with a nice light tan color. My engine pretty similar to yours top end wise.

 

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l20b .30 over W/ l18 pistons (10.0:1), ported peanut head, Isky 270/.475 cam kit, 32/36, Custom Tri-Y header, 2 1/4" exhaust.

[Rollover_Red]

also, any smoke coming out of the exhaust? pull the plugs and post pics. maybe getting some blow by the valve guides/seats and causing some major fouling of the plugs...?

[datzenmike]

The symptoms are overheating and lack of power.

 

Possibly the carb has suddenly gone lean? If under load possibly the secondary? Blockage?

[banzai510(hainz)]

620Turbo4X4

clean set up you have.

 

 

recheack the timming. re ck the valave lash

Are you in center of the timming plate and not cranked to one side.

Oil spindal correct at TDC. Rotor at #1 at TDC exactly.

 

dizzy weightsprings didnt fall off or lots of wiggle in the distributor. My bushing was worn out but It didnt cause a Overheating proplem

 

new motors might(might) run HOT in th biggining if really tight. My first L16 did for a few days for sure.

[metalmonkey47]

Thanks for the information guys!! Huge help, I'm gonna be back with a full response in a short bit, but for now I found some B9ES plugs on the shelf at my AutoZone and I'm tossing those in once I get home in a bit...

 

I've also found a 1/64 drill bit equals 1.60mm so I've drilled a spare jet I had to match, and I'm going to put it in with the new plugs tonight...

 

 

Be back later for more discussion and to answer the questions. You guys really got.me thinking.

[Stupid_fast]

You can get a 10-piece drill bit set from 1.00-2.00 mm ... That's what I have.  Really usful for tuning.  Just start with small jets and work them up until rich, buy the set one step leaner.

[Sealik]

That is not good......too much heat when seating rings....lean or rich conditions relative to throttle position....etc

Should invest in a wideband.......no guessing A/F ratios when breaking/tuning in Franken motors.

Can always be swapped to another 'vehicle' down the road if need be...less the bung of course...lol

 

Best money I spent.....

[Stoffregen Motorsports]

How new is this engine?

 

Was there something that you did prior to it's poor running?

[Sealik]

Didn't Master of Turbonics help assemble the engine????

What are his thoughts?

[datzenmike]

Running retarded will dump lots of heat onto the exhaust ports. This will be absorbed by the water jackets around them. It will also kill performance.

 

Are the advance weights stuck/sticking?

[Xnke]

Z-train, I've seen you give bad advice by the five-gallon bucketload here, on ClassicZcar, and Z-driver. I generally tend to ignore your posts, but this one I can't let go.

 

OP, ignore valve adjustment at your own risk.

[Z-train]

Z-train, I've seen you give bad advice by the five-gallon bucketload here, on ClassicZcar, and Z-driver. I generally tend to ignore your posts, but this one I can't let go.

 

OP, ignore valve adjustment at your own risk.

I've never given bad advice in my life.But that point is moot as i haven't given any advice in this topic.But you're too ignorant to see that.I just posted FACT.You do have the right to dis-agree.Just as i have the right to tell you how wrong you are.Do yourself a favor and let it go as you only lose.30 years from now you MIGHT have accumulated as much info as i have.

[Farmer Joe]

id bet the 32/36 just isnt enough... i now there could be more jetting done, but with the big cam, the ported head and whatnot, it needs more to breathe through..

 

running lean does start to make more heat..

 

maybe try a 38/38? with wides KA, it came alive after the 38..

[hang_510]

i run @ ~9.5:1 w/a 190* thermostat and BPR7 plugs and don't have an issue (almost 20K, mostly hard, miles now) when running 91

 

sounds like something changed in the timing... besides what you did.

last valve adjustment was_____ ?

[Sealik]

i run @ ~9.5:1 w/a 190* thermostat and BPR7 plugs and don't have an issue (almost 20K, mostly hard, miles now) when running 91

 

sounds like something changed in the timing... besides what you did.

last valve adjustment was_____ ?

 

Temp thread jack.....

 

Was wondering what year of block etc this is????

Haven't seen a Z22 with cooling passages configured like this.

 

 

 

Looks like a Z24 block