Weird clacking sound

[datzenmike]

You can replace or swap a rocker any time but if a used one best to use very fine wet sand paper and a sheet of glass to 'recondition it. Just wet and pull the arm across the paper in a rocking motion to knock down any high points on it and produce a dull finish.

 

 

 

 

Go to the compression stroke. Take plug out and insert about 3 feet of a 4 foot length of 3/8" nylon rope into the hole. Turn engine up towards TDC till the rope is compressed tightly against the closed valves. Take the rocker off and compress the spring and remove the spring retainer. It's possible this was damaged 10 years ago and has developed this problem recently. Replace the retainer and lash pad with used ones. You might consider swapping the rocker also.

 

Won't hurt to try and is a cheap easy fix if it works.

[banzai510(hainz)]

this is me here

Put the lash cap back in and adjust to .006 intake and .008 COLD

see what that does.

 

be honest I was leary of this fix/ as I think it is a valve seat come loose .

 

If your going to take the head off wehy not take the intake off and look and see how much carbon build up there is.

 

and if there is a sticky valve why don't you dist the coil wire and hit it with the starter and look at that section of the valve and see maybe if it jams up or rocker don't look right as it working

[athoose]

I cycled the motor and didn't see anything. Hosed the valve with silicon spray fired it up and it's working right now but I think I'll replace rocker, lash cap, and retainer when I track one down with Mike's rope trick. Probably not drive it until then. I really don't want to pull the head if possible.

 

I put an oil pressure gauge in : 8 @ 400, 15 @ 750, 23 @ 1000, 50 @2000, 60 above 2500. This is warmed up. It's 60 when I start it up but my cold start rpm is way too high, not sure how to fix this. I currently have the idle when warm set at 750, it runs better at that speed. I think I need to get a weber the hitachi is just ugh... Should I be looking at replacing the oil pump with a high volume unit. From what I've read on z forums 10psi at idle is typical. Currently, im running 10w-30 but thinking I'll swap to 15w40 rotella t4, just wondering if I should replace oil pump at the same time.

 

Thanks all!

[banzai510(hainz)]

just do the .006 and oo8 COLD  and try it.   JUST DO IT  

 

if this is stock cam and lashpad set up the lash pad will fit flush in the retainer

 

 

 

I had lash pads fall out also.. So I thighten t up abit plus my Schneider Cam specs said use these numbers. shit do .005 and .007.

 

your oil pump is fine

[athoose]

2 hours ago, banzai510(hainz) said:

just do the .006 and oo8 COLD  and try it.   JUST DO IT  

 

if this is stock cam and lashpad set up the lash pad will fit flush in the retainer

 

 

 

I had lash pads fall out also.. So I thighten t up abit plus my Schneider Cam specs said use these numbers. shit do .005 and .007.

 

your oil pump is fine

put the intake at a tight .006 and it runs fine, took it for a 45 minute drive, no issue. We'll see how long it lasts! LOl

 

The raised portion on the retainer that surrounds the lash cap is about half the size of stock, from being banged up. But I guess .002 on an inch is helping just enough to keep it in place for now. I would think the lash cap pushes on the valve tip but it looks close to hitting the keepers on the retainer. one of the retainers looks slightly higher than the other. The valve springs seems really weak too, maybe valve float is contributing.

 

[banzai510(hainz)]

If you lived close by I would give you some lash pads . Stock lash should be flush as the back is counter sunk.

 

[datzenmike]

5 hours ago, athoose said:

 

I put an oil pressure gauge in : 8 @ 400, 15 @ 750, 23 @ 1000, 50 @2000, 60 above 2500. This is warmed up. It's 60 when I start it up but my cold start rpm is way too high, not sure how to fix this. I currently have the idle when warm set at 750, it runs better at that speed. I think I need to get a weber the hitachi is just ugh... Should I be looking at replacing the oil pump with a high volume unit. From what I've read on z forums 10psi at idle is typical. Currently, im running 10w-30 but thinking I'll swap to 15w40 rotella t4, just wondering if I should replace oil pump at the same time.

 

Thanks all!

 

Oil pressure is fine. Replace later it's not that critical right now.

 

Cold fast idle is normal and should be between 1,800-2,200 RPMs. Once warm 5-10 min it should come down to 750-ish.

 

[athoose]

Got out to the jy and found a u67 head and w58 head, grabbed a good rocker and lash pad but will have to go back for retainer with rope. Thought about grabbing the U67 head for back up but the cam and rockers are rusted, bad. Could I swap the w58 cam into the U67 head without issue ( I just read you aren't really supposed to pull cam towers)? Same cam specs?

 

 A 7/77 510 had a manual, is it a dogleg 5spd? 

 

Thanks

[bilzbobaggins]

22 minutes ago, athoose said:

Got out to the jy and found a u67 head and w58 head, grabbed a good rocker and lash pad but will have to go back for retainer with rope. Thought about grabbing the U67 head for back up but the cam and rockers are rusted, bad. Could I swap the w58 cam into the U67 head without issue ( I just read you aren't really supposed to pull cam towers)? Same cam specs?

 

 A 7/77 510 had a manual, is it a dogleg 5spd? 

 

Thanks

 

Where in great lards name did you find two Datsuns in one yard in the South?

[datzenmike]

Don't remove cam towers unless desperate. They don't need to be removed to remove the cam.

 

You can swap all L series cams if you want. All interchange.

 

Grab the head anyway the rockers from a good head can be swapped into it. If available and cheap grab everything for spares.

 

The 78-'80 A10 (later HL510) had 3 speed automatics or manual 4 speeds but there was an optional dogleg 5 speed offered. Only the 2dr. hatchback had the option in '78 but all models (2,4 dr. wagon) had it in '80. If this is an '81 the  engine is a Z20 and won't fit.

[athoose]

Update,

 

Continued to drive it clacking here and there until it lost all power backing out of driveway a couple days ago. You can see on #3 cylinder where the piston and valve seat made contact. 

So, I am just looking to get this back on the road as cheap as possible while being done correctly. What all should I have done at the machine shop? Thanks!

 

 

[datzenmike]

Seats fall out when they are badly over heated. Might be cheaper to find another 521, 510 or the early 620 head from another L16. It might be fixable if welded up and then machined for a new seat. 

[athoose]

58 minutes ago, datzenmike said:

Seats fall out when they are badly over heated. Might be cheaper to find another 521, 510 or the early 620 head from another L16. It might be fixable if welded up and then machined for a new seat. 

I can easily get a u67 from a 74 l20 truck or a eighties 510 L20 head, would either of these work? The U67 cam looks rusty from sitting in a jy. 

[datzenmike]

 It will fit, but the larger combustion chamber will drop the compression ratio to a very sad 7.72. You could do this if a/ it's cheap enough and b/ you are looking for a proper 210 head to replace it later.

[athoose]

1 hour ago, datzenmike said:

 It will fit, but the larger combustion chamber will drop the compression ratio to a very sad 7.72. You could do this if a/ it's cheap enough and b/ you are looking for a proper 210 head to replace it later.

I currently have an a87 open chamber head on the L16. From what I'm reading that cc is very similar to the L20. So it looks like I all ready had a sorry cr. Am I understanding this correctly? 

[datzenmike]

 

210.... 38cc... L16 only

A87.... 45.2 and sometimes 41cc closed chamber used on  L18 only and the earliest L20B 74 610

U67.... 45.2cc  used on '75-'77 L20B

W58... 45.2cc used on '78-'80 L20B

 

So yes, the same combustion chamber size. You will need to drill two 3/8" holes for coolant flow into the intake manifold Just like the 210 and A87 heads. The U67 didn't have these.

 

[banzai510(hainz)]

The Later 80s L head might be a round exhaust port.

 

If this is a daily driver I don't worry about compressions ratios and just bolt it on if its good

[athoose]

Update, got the jy u67 head rebuilt and bolted everything back together today. Tried to fire it up but starter won't crank, no click, nothing. At first the charge light would come on, now it won't come on at all. Interior lights are working now that the charge light doesn't. I was checking out the wires near the inhibitor switch (it was originally an automatic) - just to make sure it was hooked up, and noticed a three pronged connector near it felt warm. Any thoughts on trouble shooting this? 

[datzenmike]

The start signal from the ignition switch goes through the transmission interlock switch that only allows starting in PARK and NEUTRAL. The two wires are Black/Yellow stripe. Join these two together by crimping with a connector or solder them. Twisting them together and taping them just won't do.

[bilzbobaggins]

you put the ground back on the head?

[athoose]

55 minutes ago, datzenmike said:

The start signal from the ignition switch goes through the transmission interlock switch that only allows starting in PARK and NEUTRAL. The two wires are Black/Yellow stripe. Join these two together by crimping with a connector or solder them. Twisting them together and taping them just won't do.

Meant to do that eventually, looks like it'll happen tomorrow.

[athoose]

45 minutes ago, bilzbobaggins said:

you put the ground back on the head?

Yeah, and I checked with voltmeter, just to make sure. 

[athoose]

 

Turned out grounding the Bw bcdd wire to the dizzy is not good.