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waynos 521 work truck


wayno

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3 hours ago, mainer311 said:

had to use two different height lash pads to get the wipe pattern centered for all valves. 

is this cause of the valve themselves are different lengths for intake to exhaust  or the seats on exhaust get hotter and wear faster. then the machinist grinds them both and the exhaust seat is still deeper????  Or maybe years agao soembody just replaced the exhaust seats. then it should actually be closer to the same. My u67 pretty much came out even when the guy did mien the lash was all the same lash pad size. He only replaced to the exhaust to keep the cost down. Or maybe he only di the valve huides I cant remember know. He put iron guides in for sure.

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The stems are different lengths, but the retainer grooves are the same distance from the tip, so what ends up happening is the spring retainer sits slightly higher on the longer stem. So basically in that case, a shorter lash pad gets used because the whole thing ends up closer to the cam. 

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I do not know what they did exactly, the piece of paper(receipt) says "V/Grind", "Surface", and "Weld", another thing to keep in mind is that all the things the guy mentioned when I left the head there had already been done, hardened seats were one of them, so they did not have to do all the stuff necessary to cope with the fuel they sell today, here is the receipt with their info on it in case anyone wants to talk to them. 

001.JPG.7767517e4c14d1c98b38acd6395f64a0.JPG

 

Fact is I have an extra W53 head(open chamber) that I have no need for right now and nobody would pay me what the head was worth if I had it rebuilt, I would never use the head as it is on an engine either, it has 42mm intakes and all my heads have 44mm intakes or larger, it also needs to be port matched to the dual SU intake manifold, I already have a W53 head done mounted on a Z20 block with flat top pistons that I used in my work truck very briefly on a L20b block which is in my 1966 Datsun 520 ute now that has a 219 head on it at this time, with the RV cam that W53 head had and the smaller intake valves on that L20b block it did not have the grunt/torque to move this work truck at any RPM, I was always floored and I am spoiled now since using an LZ23 for all these years, fact is if I were to build another engine for this truck it would likely be a KA or a VG30 as I already have one of them but I see no need to do that as I am semi retired now and I put 1/3rd the miles on this truck that I used to, this engine in it now will likely outlast me.

 

I believe I mentioned before that I put a straight edge on the tops of the 4 valves in the middle 2 cylinders of this engine head in the truck now after the rockers and lash pads were removed, it appears that this in this head all the valves are the same height, the  head I just had fixed the exhaust valves are slightly taller and I kept the rockers and lash pads together in order so they would go back in the same places, I will put the head together in a little while so things do not get mixed up.

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OK, I put this head back together and looked at the wipe pattern now and how it was, they are the same which is terrible if it is supposed to be in the middle, but it has been terrible for the last 9 years, it is opposite of the way it was in the engine in the truck now before I found better lash pads, now it is more or less in the middle, I got lucky, after thinking about it now I am surprised the cam did not get ruined, maybe it did and I just don't know it yet.

Anyway this head has the lobe basically pushing on the rocker arm at the edge of the pad at the post end, when I think about angles this way basically pushes the valve farther down/opens it farther, it has been this way a very long time/since I built the engine, when I thought about it I would need taller lash pads to make me turn the posts the rockers sit on down to move the wipe pattern closer to the valve end.

Here is the issue I have, I have never had an issue with the wipe pattern this head has, all my issues have been head gaskets blowing in the last couple years and detonation/knocking/pinging which likely caused the damage to the head that required welding now and a new head gasket a year or so ago.

Now I have more than one set of lash pads, but what is weird is the taller lash pads I have sit deeper into valve spring retaining cap, so it changes nothing, this is not my area of expertise, should I leave it alone since it has worked fine for 9 years or should I guess how much thicker a lash pad needed should be and order a set from somewhere or someone on here?

 

You can see it has a sliver of dark area on the left so the lobe is not travelling off the pad when the valve comes to rest again as the cam is rotating clockwise.

002.JPG.c32770b961f0993bbacac761e3988f65.JPG

 

Does anyone have an idea how many thousands thinker the lash pad would need to be to move the wipe pattern over a 1/16" to 3/32" of an inch?

 

Stoffregen Motorsports mentioned checking the wipe pattern, I only did one rocker/lobe as the head is on the bench with a 2X4 on each end to hold it up away from the bench surface, the one I checked appears to be the same as before, it is not running off the pad but it is close.

 

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002.JPG.c32770b961f0993bbacac761e3988f65.JPG

 

As the valve recedes into the head and you adjust the pivot lower to set the lash doesn't the wipe on the pad move towards the valve? If so, the wipe pattern on the rocker in the picture will move to the right and be more correct.

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MIke your right in what you said to move the adj ball end down but the lash would be more than .010 .012 and be noisey

 

 

 

 

heres the aussie site. you would want the RECEESED ones if still using the stock retainers

Mainer on here got soem so ask the size equiv you think you need. I was told stock lash pad is .120

http://www.precisionshims.com.au/products/slotted

Edited by banzai510(hainz)
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Machine shops are well equipped to set up rocker geometry because they usually have an assortment of lash pads. Another trick machine shops use is light pressure setup springs. The light springs are installed before final head assembly and allow you to turn the cam by hand. What I'm saying is that if you're having a head rebuilt, think ahead next time and have them set up the rocker geometry too.

 

Wayno, trial and error is the only way to know for sure. Also, checking to see if the cam is bad is easy. You look for any wear that's not smooth and shiny.

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As Hainz said, stock thickness is .120”

I had to use .150 and .180 on mine because I have a reground Nissan cam with a smaller base circle. That got my wipe pattern nice and centered.

 

The guy at that Precision Shims site is a nice guy, but shipping takes a little while because he’s in Oz. His pads have the stock recess in the bottom to keep more of the thickness below the top of the retainer. Less risk of them falling out.

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  • 2 weeks later...

I have a question about Z22 blocks, I have made/built 2 different LZ23 engines(I built them several years ago), the first one I made out of a Z22E block, that one was in my truck likely 8+ years and recently had the head issue, the second one in the truck now was made with a Z22S block, are these blocks different?

 

I ask because this one in the truck now does not have the torque or power the old block has, it feels more like an L20b than an LZ23, it is gutless starting out on any kind of incline, I have to ride the clutch to get it moving. 

 

I have been advancing the timing a little bit, I do not remember what it is at now but I can go another couple degrees again as I have not heard any knocking/pinging.

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There were early and late rods and pistons. Early were the same as the truck. Later rods were longer and the piston pin height reduced to match the same overall length. Later engines would be long rod though the stroke remained the same. You put Z24 pistons on Z22 rods? Well the longer later rods would have pushed the Z22 pistons out of the block so not that.

 

Open chamber head 8.4 and closed 8.8

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I expect I should have mentioned another thing, this engine using the same starter turns over way faster now, I do not expect I noticed it before as it started so easy/fast before, the moment I turned the key it would at least try if not start, now it turns over a little longer and then starts, but it turns over really fast, no L block I have ever owned turned over this fast.

 

I am using the same starter as before, it was used for the other engine also, this was a Z22S block, it has Z24 pistons and Z22S rods as I recall, the head is slightly different, the intake valves are larger on this one than the damaged head, I am using the same intake, the only difference other than that is I am burning non ethanol premium gas right now, fact is I did not notice the power loss before I switched over to the premium, oh and It is not knocking now, when I was burning the regular pump gas it was knocking/pinging.

 

The torque reminds me of that RV cam I used on that engine other head I built after my last L20b  before I built my first LZ23, no torque and no HP at freeway speeds, I am having to drop into 4 gear on the freeway sometimes again just to keep it at 60mph, I thought I was past this, I have 4.6 gears in the rearend.

 

I have an estimate to do, I will advance it a couple degrees before I leave, but the torque issue is a major issue for me, sometimes when I let out the clutch I think it is going to die/quit moving instead of accellerating, I have to push it the clutch and get it revving again and ride the clutch to get it moving at a much higher RPM.

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Do a compression test. Lower compression will be easier to spin with the starter.

 

Any chance you had regular direct drive and gear reduction starters?

Advancing the ignition might slow the starter turning.

 

Cam timing:

If sprockets worn/chain stretched or if head was milled or set on the #1 hole by mistake the crank will be ahead of where the cam events should be occurring. I guess you could say that the cam timing is later or retarded? This benefits high RPM power/torque but at the sacrifice or low and mid range power. 

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Im guessing

I would check the timing on the cam, swap out the dist if you used a different one. You swap oil pump ?off a tooth?

Is the same carbs?  you dont have like a 38/38 or a 32/36 with the 2nd barrell spring loose?  I thought you have SUs on this?

 

like your loosing vacuum on the carb(s) or going out of time.

 

what does your timing gun say at idle?

 

fuel filter

 

when I had a 38/38 on my 521 I rally had to feather the carb/clutch when going up a steep hill from the bottom of a stop sign. I hated it and went back to the 32/36  but the 38 38 was faster beside just that one issue

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OK, this is the closest I can get the groove to the notch on number 1 dowel hole.

001.JPG.da3bea3abd1ad34cd5b7fcfdf18c3577.JPG

 

Number 2 and 3 dowel holes have it far to the right barely touching the groove, this was the closest I could get it to Mikes photo he posted, I ran the other engine for years with the groove way right of the notch, I only started having issues after I timed the cam properly.

 

I did a compression check, 1 thru 4 as follows, 165, 175, 160, 160, I did not like the results as my other engine with a blown head gasket and head damage had higher numbers, so I checked my head bolts and the ones between 1 and 2 cylinders were really loose, same with the ones between 3 and 4, they were kinda loose, the rest were a lot better(middle and both ends), I torqued these last around 2013 when I put it together, anyway I do not know if these numbers above are good or bad or somewhere in between, before I started this engine after sitting all them years in my spare room in the house I squirted oil in all the cylinders and it sat for a while then I turned it over without spark plugs in the holes until I had oil pressure on the gauge and the top end was soaked when I looked thru the valve cover filler hole.

 

I also checked my valve clearances, they were all where I set the gap a few weeks ago.

 

This stuff kinda annoys me, it is the same engine/block, same pistons, and it is also almost the same head(larger intake valves), I just do not understand how that wasted head that had coolant get into the cylinders could have higher compression numbers.

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4 hours ago, banzai510(hainz) said:

Im guessing

I would check the timing on the cam, swap out the dist if you used a different one. You swap oil pump ?off a tooth?

Is the same carbs?  you dont have like a 38/38 or a 32/36 with the 2nd barrell spring loose?  I thought you have SUs on this?

 

like your loosing vacuum on the carb(s) or going out of time.

 

what does your timing gun say at idle?

 

fuel filter

 

when I had a 38/38 on my 521 I rally had to feather the carb/clutch when going up a steep hill from the bottom of a stop sign. I hated it and went back to the 32/36  but the 38 38 was faster beside just that one issue

 

I did use a different distributor as the one that was in it was wasted, so I used a 1980 Z block distributor(4 plug type) and I made my own plate to get it in the right spot, it starts great, but this LZ23 engine does not have the power my old LZ23 engine has after 8 years of beating the shit out of it.

I have dual SUs on this engine, I have had SUs on it for over 20 years.

It really does not matter about the oil pump as I made a plate for the distributor to Orient it to fit in the room I had as the vacuum advance was on the other side and my power steering hoses were in the way, today I timed it at 10 degrees BTDC at an idle but I have not drove it yet, it was timed at 5 or 6 degrees BTDC at an idle.

 

I was watching the fuel filter bubbling away, it has an electric fuel pump now.

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5 hours ago, datzenmike said:

Do a compression test. Lower compression will be easier to spin with the starter.

 

Any chance you had regular direct drive and gear reduction starters?

Advancing the ignition might slow the starter turning.

 

Cam timing:

If sprockets worn/chain stretched or if head was milled or set on the #1 hole by mistake the crank will be ahead of where the cam events should be occurring. I guess you could say that the cam timing is later or retarded? This benefits high RPM power/torque but at the sacrifice or low and mid range power. 

 

As I remember when I built both my LZ23 engines I used new timing chain kits(gears/chain/tensioner/guides), this is not a used chain.

It is not a gear reduction starter, it is a used starter I picked up at the Brooks meet(Canby replacement) 2 years ago, it was on the other engine for a while and that engine turned over a lot slower than this one does, I do not know how fast it turns over now since doing the timing as it starts right up the moment I hit the starter when it is warmed up.

 

As I said I cannot get the groove/notch to look like the photo you posted, I tried it in 6 different positions and number 1 dowel hole was the closest I could get it.

Edited by wayno
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OK If the groove is to the left of the line above it, the cam events will be later. This means the intake will close later. This means the piston is farther up the cylinder. Do you follow? This means the compression will be lower as there is less volume above the piston to compress after the intake closes. This is way there is a power loss at low speeds when the chain/sprockets are worn.

 

The width of line etched into the cam thrust plate is 4 degrees of cam timing. The holes 1, 2 and 3 are supposed to be 4 degrees of adjustment each

 

What I would do is try number three hole and get the groove as far to the right as you can..... and then move the sprocket ONE tooth counter clockwise. Each tooth (there are 40 of them) is 9 degrees. So advance it and then remove 9 degrees by moving one tooth back.

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That will work but going from 1 to 3 is, (or should be) 8 degrees. By coming back one tooth 9 degrees you should be moving back 1 degree. perhaps it will split the difference. It's worth trying to move the V slightly to the left under the line more.

 

Yes, moving the cam events sooner, as in the intake closes sooner before the piston has traveled up the cylinder as much will increase the compression and it may ping with the advance you have dialed in now.

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Like I said before, I tried it in 6 different positions and that photo had the groove mostly in the notch, all the rest of the positions had it left or right farther out of the notch but the cam might not have been in the proper place as I cannot count links.

 

I will play with it tomorrow, I never had so many issues in the past, I just set it at 10am/2pm and put the gear on the cam and it ran fine even though the cam was timed wrong, only when I fixed it did these issues I have had appear, although the wipe pattern on the cam was wrong, that has nothing to do with cam timing and knocking/pinging, it was just set up wrong by the machinist.

 

 

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Again, I will state that learning how to degree a cam and using that method (whichever method is chosen, using a degree wheel or by the split overlap method) can save time. It is just part of the engine building process.

 

When building an engine for money, there is a certain amount of precision that needs to be accounted for so the end user can just plug and play their new powerplant. The first step is verifying TDC, the second step is setting the cam timing. From there, any distributor can be used, or any carburetor, without worry.

 

As I said earlier, there are so many variables...but you need to start with a baseline.

 

Have you checked TDC, or the cam timing? Are the two engines even using the same cam?

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