1980 4WD 720 engine problem

[spottedog]

I have a question about a “Frankenstein” engine I put together last year.

It is a stock rebuilt Z24 block with a W58 L20B open chamber cylinder head.

Before assembly using the glycerin and a syringe method, I calculated the compression ratio to be about 10 – 1, using a Felpro Cylinder Head Spacer Shim (21178SP) and a standard Felpro head gasket.

Holes were added to the gaskets to accommodate the extra water passages in the L20B head. Since the Z24 block is taller than the L20B the timing chain had to be lengthened by four links using two BMW timing chain master links. The cam timing is spot on so I don’t think that is the problem. The timing case cover bolted up except for about a

Edited December 2, 2008 by spottedog

[banzai510(hainz)]

go to the 510realm and post this ques

 

Yellowcar in there had a LZ24 set up He used a mecedes chain I believe. You maybe able to ask him on there(PM him)

or maybe someone else will know.

[Cuts metal like mad]

I believe it was the merc masterlinks and not the whole chain. Sounds like timng is still off...

[HRH]

You didn't get the distributor drive gear off a tooth, did you? You're also going to need to richen up the 32/36 a bunch to avoid detonation. Probably want to be running around 145-150 main jets and 165-180 air correctors. I'd say a 55 idle.

 

The other thing is a W58 head is the crap steel-lined smog head, not too great for flow. A U67 or U60 would be much better for that combo. And of course the timing chain still seems suspect. I know you have to make a custom chain, but I'm not sure how many links needed adding.

 

Is the cam in time? What setting do you have it on? 1, 2, or 3? And is it a stock cam?

[datzenmike]

With 10 to 1 you are going to get ping so your timing falls where ever it falls to keep it quiet. Set the crank at TDC using the timing notch on the rear of the pulley and the ZERO on the timing plate and check the cam sprocket VEE in relation to the etched line on the cam thrust plate. The line has to be at the Vee or just to the left for proper cam timing events. You may have to remove the sprocket and try another setting.

 

W-58 heads are more or less the same as a U-67 except for port shape and those liners. The liners can be removed with a bit of bother... I've done this.

 

Are you running stock L20B exhaust manifold?

[datsunaholic]

He said he has a 32/34, not a 32/36. A 32/34 is a fairly small "smog legal" carb that isn't made anymore, and it's too small for a 2.4L.

[jesusno2]

I would guess that that motor is running super lean! I would invest in a 38 dgas if you plan on keeping the downdraft type carb I just ran into a 22r toyota this past weekend with the same exact issues. Pulled the plugs out of it and they were bright white! The cause of it was not so much the carb but the vaccumm leaks around the throttle shafts and base plates. So might wanna check for vaccumm leaks also.

[72240z]

He said he has a 32/34, not a 32/36. A 32/34 is a fairly small "smog legal" carb that isn't made anymore, and it's too small for a 2.4L.

 

Good catch, I completely missed that. Thats the problem in my opinion as well.

 

 

I think it's a shame to go through all that trouble and end up using that head and carb. I'm guessing its because you had them already?

 

I would correct the carb, gut the emission sleeves, loose the shim and groove the head. Just my .02.

[spottedog]

go to the 510realm and post this ques

 

Yellowcar in there had a LZ24 set up He used a mecedes chain I believe. You maybe able to ask him on there(PM him)

or maybe someone else will know.

I have been reading over there on the site, GREAT stuff! Thanks!

[spottedog]

You didn't get the distributor drive gear off a tooth, did you? You're also going to need to richen up the 32/36 a bunch to avoid detonation. Probably want to be running around 145-150 main jets and 165-180 air correctors. I'd say a 55 idle.

 

The other thing is a W58 head is the crap steel-lined smog head, not too great for flow. A U67 or U60 would be much better for that combo. And of course the timing chain still seems suspect. I know you have to make a custom chain, but I'm not sure how many links needed adding.

 

Is the cam in time? What setting do you have it on? 1, 2, or 3? And is it a stock cam?

My plug color is just on the dark side, and I can start it up cold without using the choke, so I assume it is jetted on the rich side. Oh and the tailpipe is blackened.

 

Four links added (at least a even number)

 

Stock cam is in time, 2nd hole, index just a bit to the left.

 

You got me thinking about the dizzy drive gear ......gotta check that one. Thanks!

Edited December 4, 2008 by spottedog

[spottedog]

With 10 to 1 you are going to get ping so your timing falls where ever it falls to keep it quiet. Set the crank at TDC using the timing notch on the rear of the pulley and the ZERO on the timing plate and check the cam sprocket VEE in relation to the etched line on the cam thrust plate. The line has to be at the Vee or just to the left for proper cam timing events. You may have to remove the sprocket and try another setting.

 

W-58 heads are more or less the same as a U-67 except for port shape and those liners. The liners can be removed with a bit of bother... I've done this.

 

Are you running stock L20B exhaust manifold?

Cam timing is spec, stock exhaust other than high flow muffler.

Next time things are apart I will try to those steel liners. Thanks!

[spottedog]

I would guess that that motor is running super lean! I would invest in a 38 dgas if you plan on keeping the downdraft type carb I just ran into a 22r toyota this past weekend with the same exact issues. Pulled the plugs out of it and they were bright white! The cause of it was not so much the carb but the vaccumm leaks around the throttle shafts and base plates. So might wanna check for vaccumm leaks also.

 

Actually it burns a bit rich, plug color a little dark.

I am pretty sure no vacuum leaks but the #2 intake valve seat is receding into the head, lash adjuster on that valve is bottomed out, all I could do to get 0.012 lash. Gotta pull the head and get hard seats pressed in.

$$$$$$$$ :(

[spottedog]

Good catch, I completely missed that. Thats the problem in my opinion as well.

 

 

I think it's a shame to go through all that trouble and end up using that head and carb. I'm guessing its because you had them already?

 

I would correct the carb, gut the emission sleeves, loose the shim and groove the head. Just my .02.

Leave the shim out? Wouldn't that raise the compression even more?

[banzai510(hainz)]

if the oil spindal/dzzy tooth was off you probaply couldnt even get it timmed to 4 deg and 12 deg as 1 tooth would take it too far to one side when you look at it with a timming light.

But its good to ck. Sometime people put on the wrong timming plate if it came from another vehicle. Its enought to start but then goes out of time(something like that)

 

Time to TDC and see where the rotor points and hopefully its ON #1 plg wire and there is more than enough movement in the timming plate. No clocked to one side. under most L series dizzys there is a 8mm to move the timming plate more if needed.

[72240z]

Leave the shim out? Wouldn't that raise the compression even more?

 

Ya, thats why I added grooving the head. Free and effective.

[spottedog]

Ya, thats why I added grooving the head. Free and effective.

 

Grooving the head? I am not familiar with this.

Explain please?

[datzenmike]

This is a W-58 head and is an open chamber, so grooves are out.

 

Google it. There's several sites about carving grooves in the quench ares pointing toward the spark plug. The claims are a bit much, but in theory it could promote extra swirl directed at the plug. I don't see any harm in it.

[spottedog]

Checked the distributor drive and rotor position today, and sure as hell looks like I did fubared it. :) Drove it 5000+ miles this way.

This thing is a combination of L20B and Z24 parts so I don't even know if I used the correct pedestal. The dizzy is off a L20B.

Check these 'pics please.

 

http://im1.shutterfly.com/media/47b8cc25b3127ccec59da17812a600000040O00AZs2LJy1cOWIPbz4M/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/

 

http://im1.shutterfly.com/media/47b8cc25b3127ccec59d0b6912e200000040O00AZs2LJy1cOWIPbz4M/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/

 

Looks like I will be under this heap tomorrow dropping the oil pump. :o

 

I have to compliment level of expertise on this board, thank you gentlemen.

Edited December 5, 2008 by spottedog

[datzenmike]

In theory the distributor drive can face any direction as long as the rotor is under any cap plug wire (just call it #1) and as long as there is enough room for proper adjustment of the advance.

 

To make it easier to relate to everyone else here on earth, you know, so we are all on the same page, I would drop the spindle and turn about 180 degrees around.

 

In the first picture you can see that the slot is a little off center and needs to have the larger half to the right and the slot in the 11:28 position. Where ever the rotor points, the plug wire above it becomes #1 and move all the other wires around 1,3,4,2 in a counter clockwise direction.

 

I don't think you can use the Z24 pedestal, it will only work with the L one. Also 4,100 lbs sounds high for a 720. Maybe that's the GVW? Without a full load it should be less I think. A lot less.

Edited December 5, 2008 by datzenmike

[spottedog]

In theory the distributor drive can face any direction as long as the rotor is under any cap plug wire (just call it #1) and as long as there is enough room for proper adjustment of the advance.

 

To make it easier to relate to everyone else here on earth, you know, so we are all on the same page, I would drop the spindle and turn about 180 degrees around.

 

In the first picture you can see that the slot is a little off center and needs to have the larger half to the right and the slot in the 11:28 position. Where ever the rotor points, the plug wire above it becomes #1 and move all the other wires around 1,3,4,2 in a counter clockwise direction.

 

I don't think you can use the Z24 pedestal, it will only work with the L one. Also 4,100 lbs sounds high for a 720. Maybe that's the GVW? Without a full load it should be less I think. A lot less.

 

I will change the shaft position tomorrow (unless it rains)

 

As to the weight, about a month ago I went to our County landfill to dump household garbage (this is a little sub rural mountain town) they make you drive onto a scale to make sure what you tell them is in the bed really is what is in the bed. :) (people try to sneak in engine blocks and stuff, this is a composting landfill)

At the time I had two 32 gallon plastic trash cans, maybe 30 pounds each, nothing else. For the hell of it I asked the attendant "hey what does this thing weigh?" 4100 the man says. BS I says.

"This scale is recertified every 90 days because the DMV and Highway Patrol use it" he tells me.

A friend sold a 1955 Chevy pickup to some guy in England, I mentioned the above to him, he said he had to have his truck weighed prior to shipping and the full size Chevy was about 600 pounds lighter!

I dunno. My truck is 4WD and does have a really burly frame but I still find it hard to believe. 'Have not been able to verify the weight on the web so far.

[datzenmike]

I have a 620 on an '82 2wd frame. I welded in a 720 T case and a Toyota solid front axle, extra leaf springs and it weighs 3,400 lb with the L20B engine. I have a Z24 in it now, don't know the weight.

[72240z]

This is a W-58 head and is an open chamber, so grooves are out.

 

Google it. There's several sites about carving grooves in the quench ares pointing toward the spark plug. The claims are a bit much, but in theory it could promote extra swirl directed at the plug. I don't see any harm in it.

 

I could be wrong the I 4 L series isn't my strongest area but aren't the chambers on the u67 and w58 about the same? I ask because I am more familiar with the u67 which is open chamber and it has plenty of meat to be grooved. The chamber would have to be completely domed for grooves not to be viable and even then you can grove the piston with identical results. Obviously not ideal though structurally.

 

Either way though I stand by that advice, I really hate shims and that bump in comp nets him 10-15hp/tq where he needs it plus better mpg and cleaner emissions.

 

I'm going to drop it because I don't want to be a thread jacker but I want to say I have 1st hand experience with groves on a l series (and others) and the claims are not exaggerated one bit. 11.2 comp on 87 octane during summer with only a 2 degree advance no knock at all, better mpg, WAY better power esp down low. Thats on a non cross flow 2 valve head that imo is a very poor design. Made not just a believer out of me but a preacher as well :-).

[72240z]

I have a 620 on an '82 2wd frame. I welded in a 720 T case and a Toyota solid front axle, extra leaf springs and it weighs 3,400 lb with the L20B engine. I have a Z24 in it now, don't know the weight.

 

My 89 d21 kc 4x4 v6 is 4800 or so the scrap man says. Assuming that is true I think 4k for a 620 is way high. That the only reason I don't own one is I cant tow shit with it due to its weight. The d21 is already too light.

[datzenmike]

U-67 are open chamber and are basically identical to the open chamber W-58 except for the exhaust port size. The W-58 does come with a closed chamber head.

 

As I understood it, the grooves are cut in the flat quench area and direct the pinched gasses at the spark plug. This can't happen on an open chamber head as there is no quench or pinch area between the piston top and the head surface.

 

Here's the first one I came to:

 

http://somender-singh.com/content/view/7/49

 

Here is one of their grove heads:

 

 

Here is an open chamber U-67 head:

 

http://i138.photobucket.com/albums/q251/datzenmike/motorU-67openhead.jpg[/img]"]

 

For the full effect you need a quench area. The U-67 doesn't really have one. Grooving it 'might' have some effect, I don't know. A closed chamber head like this one would work:

 

http://i138.photobucket.com/albums/q251/datzenmike/headL245hp1.jpg[/img]"]

Edited December 5, 2008 by datzenmike

[72240z]

Mannnnnn I was trying not to thread jack lol. A flush area grooved will have greater effect but it is not necessary, or so that was my take off his site. I believe the reason being because in high comp even with an open chamber the piston must be coming passed the deck or you wouldn't have the comp anyway(most cases). All and all though lets say your right and you have to have a close chambered head. He went through all that trouble to weld a 1/4 gap in the timing cover AND machined it, he could have just as easily done that do the head. Just like the last example of a close chambered head you showed, those chambers are welded.

 

I want to say I'm just discussing this not arguing. Grooving has more then proven itself to me but there are still gray areas for sure.