Found this while replacing head gasket

[banzai510(hainz)]

When you really think about it there really isnt that much to these heads.

 

You have a good set up there

 

hopefully you put this on a L20.block!!!!!!!!!!!!!!!

 

I have a pumped L18 and I wish I I started out ealier with L20s if the blocks are good. Alot have center cracks in the water passage between the bolt holes.I

had a pumped l20 in the 90s and it would scoot!!!!!!!!! sold car later destroyed by kid.

[Silky_Johnson]

When you really think about it there really isnt that much to these heads.

 

You have a good set up there

 

Yeah, I've actually found it fairly easy and understandable to work on. I've got a good setup in the head, but the engine has been running like :poop: for a long time. Hopefully, after doing some block work, it'll tune in real nice. I'm getting tired of the rumbly idle and lack of power. I was losing speed big time up any hills unless I was up above 2800 - 3200 RPMS.

___________________________________________________________

 

I made another discovery today. I measured the head and came up with 4.218''. Isn't the stock thickness supposed to be 4.248? Looks like I've also got a shaved head, so I'm definitely not putting flattops in.

[banzai510(hainz)]

Hopefully, after doing some block work, it'll tune in real nice. I'm getting tired of the rumbly idle and lack of power. I was losing speed big time up any hills unless I was up above 2800 - 3200 RPMS.

 

 

waht carb set you running? If down draft maybe it wasnt jettied for a cam like this. if duel was sync wrong, dizzy bad. off atooth?

 

To me those pistons with those valve marks are bad news. To me made by the valves as How can a mchine match them up that good? Put soem play doh in there and bolt that down and see what it does. I would get a L20 and get the coorcet clutch set up to run on a 6 bolt crank.

 

your head is minmal shaved I would bother overly thinking about it.

 

if that cam is 480 or so its not that huge. Maybe was timmed wrong to hit pistons?

[Silky_Johnson]

Hopefully, after doing some block work, it'll tune in real nice. I'm getting tired of the rumbly idle and lack of power. I was losing speed big time up any hills unless I was up above 2800 - 3200 RPMS.

 

 

waht carb set you running? If down draft maybe it wasnt jettied for a cam like this. if duel was sync wrong, dizzy bad. off atooth?

 

To me those pistons with those valve marks are bad news. To me made by the valves as How can a mchine match them up that good? Put soem play doh in there and bolt that down and see what it does. I would get a L20 and get the coorcet clutch set up to run on a 6 bolt crank.

 

your head is minmal shaved I would bother overly thinking about it.

 

if that cam is 480 or so its not that huge. Maybe was timmed wrong to hit pistons?

 

I am running dual Mikuni PHH40s. The fuel mixture is pretty good now. I'm running 65 pilots and the idle screws are 1.5 out. I think I need to boost the pump nozzles to get better throttle response. I synced the carbs as best as I could, but the number one runner was off. With my syncrometer, the runners measured as follows:

 

1. 2.5 - 3ish

 

2. 5

 

3. 5

 

4. 5

 

I also began to notice that right when the carbs were switching from the pilots to the mains, there was at least one cylinder that wouldn't switch over unless I continued to accelerate. Cruising at around 2600 RPMs, unless I pushed it a little harder, the exhaust note would make a weird vibration sound right where they switched to the mains.

 

I replaced the dizzy with a rebuilt part and confirmed that it was timed correctly. Ignition is good. I watched your video a bunch of times about a year ago and confirmed that everything was as it should be. I did notice that the cam gear was set in the #1 position? I'll set it back at #2 and maybe that will help?

 

I'll try to find out if the pistons were hitting. I don't have any playdoh on hand, but I suppose I can go to the store and get some. I think I'll get purple; that'd be real cute. So, I need to put the head gasket in to get the right spacing for the test, but I'm assuming I don't need to torque it down? Should I just do a couple of pounds on each bolt and call it good so that I can reuse the gasket?

 

I would love to swap in an L20B, but it just looks like there aren't that many available??? And I really want to get one that, A. isn't cracked like you mentioned, and B. a non smoking, even compression runner. Tristan was willing to give up dibs on Jrock's L20B, so that I could get my L18 rebuilt, but the problem is that I would probably just want to keep the L20B and not sell it back to Tristan after the rebuild. I've gotta get my car running, so I can't really wait around for an L20B to pop up.

[banzai510(hainz)]

You can alwaYS buy a cheap FELPRO GASKET.

 

i ALWAYS ck my jet bloclks to make sure they together and clean. Mine always back out on me.

[Silky_Johnson]

L20B it is. Going to pick up the engine this weekend.

[banzai510(hainz)]

Rememeber if you get a l20 200mm flywheel youll use the same T/O bearing and collar and clutch.

510 and Roadster are the same diapphrame height.

 

If you get a truck fylwheel youll use a different set up

 

a 200sx is different diaphrame height even dough its a 200mm.

[Silky_Johnson]

The block doesn't come with a flywheel. I'm going to have to track one down, so it depends on what's available.

 

I've already been doing some research on flywheels and what I can use. It sounds like anything with a six bolt configuration will work fine with matching clutch setup? Does anybody have anything against the 280 2+2 kits on eBay that include the flywheel? For instance: http://www.ebay.com/itm/EXEDY-CLUTCH-PRO-KIT-F1-HD-FLYWHEEL-1975-1983-NISSAN-280Z-280ZX-2-2-2-8L-V6-SOHC-/400316742313?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3A280Z&hash=item5d34bcbaa9&vxp=mtr

 

If these are a bad idea, point me in the right direction. And if anyone has a six-bolt flywheel laying around, by all means let me know what you got.

[banzai510(hainz)]

Thats almost too good of a price !!!that flywheel has to be made in China. Need to find out if ballanced

However it might be more than enough for a 510. 240 mm flywheels are heavy. as the cars they came from were heavy,more mass to get it rolling.

But to me what I read is the 280 zx 2+2 is a 240mm clutch set up and its really heavey pedal(800KG)

 

youll need the T/O collar

[Silky_Johnson]

I've got a lead on a flywheel. I'll figure out clutch stuff later.

 

In the meantime, I did the wipe pattern on all rockers. My photography isn't real good, and I may have gotten confused on which valves I was taking a picture of, but they're pretty much all the same. My numbering is from 1 - 8, #1 being the valve closest to the front of the engine/radiator.

 

 

 

Spark plug side, 1 & 2:

 

 

 

 

 

Spark plug side, 3 & 4:

 

 

 

 

Spark plug side, 4, 5, & 6:

 

 

 

 

Spark plug side, 7 & 8:

 

 

 

 

Manifold side, 1 & 2:

 

 

 

 

Manifold side, 3 & 4:

 

 

 

 

 

Manifold side, 5 & 6:

 

 

 

 

Manifold side, 7 & 8:

 

Terrible picture, and I'm not even sure these are 7 & 8

 

 

 

 

Anyway, you get the idea. It looks like I've got at least an 1/8'' on the spark plug side, if not more, and only around a 1/16'' on the manifold side on most rockers. All lash pads measure out at .220. Should I do anything to even out the wipe pattern? It seems like I would need smaller lash pads; .210 or .200?

 

Another item of note is that when I adjusted valve lash, I adjusted per spec at .008/.010 cold with the cam lobes pointing directly up (12:00). I inadvertently stuck a feeler under one intake lobe when it was pointed at 2:30 or so (after being adjusted to .008), and I could get up to a .011 feeler under there. Is this supposed to happen? Should I be adjusting valve lash with the lobes pointing at 10:00 and 2:00?

 

I've got more good news on the head. I measured the valves, and it looks like I've also got the larger 1.38'' exhaust valves. I keep finding all kinds of nice surprises.

[banzai510(hainz)]

some of those are looking pretty close esp the manifold side and yeah I think you need smaller.

 

10 2 or 12 is all good I believe.

 

as for adjusting to .008 and you get a .011 under there its kinda hard to set the pivot ball and when locking the jam nut the other soemtimes follows and you loose a gain whatever way it locks down at.

[Silky_Johnson]

Looks like lash pads are cheap on nissanparts.cc. Should I go with .210? .200?

[Silky_Johnson]

I guess my question is if there is a way to know what lash pads I should get without the trial and error process? I'm not sure how sensitive the adjustments are in relation to the wipe pattern. Would .200 lash pads put me on the other side of the rocker?

[Silky_Johnson]

I just thought of something else. My head is probably shaved .030, but my head doesn't have any cam tower shims. Is this something I should address, or is it not enough to cause slack in the timing chain?

[Sealik]

I guess my question is if there is a way to know what lash pads I should get without the trial and error process? I'm not sure how sensitive the adjustments are in relation to the wipe pattern. Would .220 lash pads put me on the other side of the rocker?

When I set my cam up....150 lash pads just caught the edge of the rocker.

It took 180s and 190s to move the pattern away from the edge....soooo....it was about .030 -.040 to center the wipe pattern

 

Thicker pads move the pattern to the valve side. Thinner pads will move it to the pivot side.

 

Maybe try some 200s

 

Also....I only had 150 pads at the time

Sooooo...I cut up a sacrificial .010 feeler gauge into small 'round' pieces.

These pieces were then placed under the 150 pad....one at a time, until I centered the pattern

Better to know what I needed before I placed an order............. :D

[Sealik]

I just thought of something else. My head is probably shaved .030, but my head doesn't have any cam tower shims. Is this something I should address, or is it not enough to cause slack in the timing chain?

 

Well...in 'theory' if you shim the towers to compensate for the .030 shave, you've now raised the cam .030 over the rocker

 

Which in turn change the wipe pattern after one adjusts the lash.

Might be for the better.........................maybe

[I'm BLUE]

Well...in 'theory' if you shim the towers to compensate for the .030 shave, you've now raised the cam .030 over the rocker

 

Which in turn change the wipe pattern after one adjusts the lash.

Might be for the better.........................maybe

 

x2 big time !

[banzai510(hainz)]

Nissan might have the pads.

Nissanmotorports is out of Tenn now and I havent bought from them.

Got to ck if in stock.

 

you can go to nissanparts.cc

enter M - the part number and should pop up.

[Silky_Johnson]

Thanks for all of the help guys. I'm going to start with shimming the cam towers, and then I'll find out what happened to the rocker geometry/wipe pattern as a result. If I still need different sized lash pads, I'll take care of that after the shims, but I think the shims are gonna put me pretty close on the wipe pattern. I can't wait to bolt this back down onto a block. I am desperately hoping that I'll have less noise in the valve train after getting everything setup correctly.

 

While I'm on the subject, does anyone know the size of the head saver shims on silver-seal.com? http://www.silver-seal.com/c=1seaM29PTj1HvsiouT0eQsnky/product/HSDT1000/Head-Saver-Shim-Kit-For-Datsun-4-Cyl.html It would appear that they are .015'', but I just want to be sure. The head saver shims on eBay claim to be .020'', and I'm guessing they're probably made by the same people.

 

I'm picking up an L20B on Saturday, so the swap will start pretty soon. I'll post pictures of what I'm doing to keep everyone updated (unless I mess up and am too embarrassed to post pictures). It's probably going to take a little while, as I want to do things right and clean. I'm hoping to prep and paint the block and oil pan before it gets plugged into its home. Any suggestions on block paint brands/colors? I like the gold engines that I have seen. I would probably be lynched if I said Chevy orange? My guess is someone is bound to chime in and suggest the original blue... The engine bay is going to get a bath too. There's no need to paint it; it just needs cleaned up.

[Silky_Johnson]

While I'm on the subject, does anyone know the size of the head saver shims on silver-seal.com? http://www.silver-se...-4-Cyl.html��It would appear that they are .015'', but I just want to be sure. The head saver shims on eBay claim to be .020'', and I'm guessing they're probably made by the same people.

 

I just got a reply back from Sliver Seal, and the cam shims are .015. Just what I need.

[Silky_Johnson]

So I have started el twunnybee swap, and things have been going okay with the exception of one broken bolt. No biggy.

 

I was cleaning up the block on the engine going into the car, and I decided to try wiggling the pistons. None of them move except for the piston at cylinder #1, which has some play. I can wiggle it back and forth about .015 or so. I'm assuming that this is a fatal error on the block, right? It's not possible that compression is okay right? Is it possible that the rings expand when they get hot and seal up?

 

So what should I do? Bolt it up, run it, do a compression test and see what happens? Should I just re-ring all of the pistons while I've got the block out? Would it be a stupid idea to just re-ring piston #1? I would rather not have to work on the block again once I get it all in and running. Suggestions?

 

By the way, I bolted down the head, timed everything, and installed spark plugs, and when you crank it over, you can hear air escaping out the bottom. I still have the oil pan off.

[datzenmike]

The piston to block clearance is between 0.001" and 0.002"... not enough to feel I think.

 

No the rings won't seal 0.015"

 

Rings are not likely the problem here. You should measure the bore that the pistons fit into. Across the top of the bore about 1/2" down... then at 90 degrees. Then 2" and at 90 and then 3" and at 90 for 6 measurements. These measurements will show taper, (wider at the top where all the wear is) and out of round. (oval or egg shape)

 

If the bore is worn past the possibility of fitting new rings and getting the proper clearance, then it must be re-bored and oversize pistons/rings installed. Basically you will have a new motor.

[datzenmike]

By the way, I bolted down the head, timed everything, and installed spark plugs, and when you crank it over, you can hear air escaping out the bottom. I still have the oil pan off.

 

Normal. At 3,000 rpms there is probably less than 1/100th of a second for this to leak out. Not much will get by. Besides the rings are crushed tightly against the cylinder wall by the exploding gasses for an even tighter seal.