My engine rebuild is killing me....UGG

So my machinist just told me the OEM lash pads i ordered were too thick...they are .120"

He said he needs about .080"

Can anyone help here? Not sure if these are even available. Only thing i saw was 

https://zcardepot.com/products/isky-valve-cap-lash-pad-custom-racing-cam-l24-l28?_pos=2&_sid=d43713ea7&_ss=r

They say .080" for something but i am not sure if they will work with everything else being OEM (not a performance cam) and such

thanks

If the lashes aren't "100%" (whatever that means) what could happen? my machinist can't seem to explain the possibility to me

I wrote some stuff then did a Google and realized that there's something odd about your problem.  0.120" doesn't even seem to be OEM.

https://www.thezstore.com/page/TZS/PROD/10-2041A

That really doesn't make sense. 120 is close to stock. What did he do to the head? 

  

2mm are small lashpads. do you have new valves? springs? 

my guess is there is something wrong with the wipe pattern on the rockers? if the head was machined i may need shims under the cam towers. You should ask if it was machined, was it machined both top and bottom and how much was taken off. Was it machined to make flat (warped) if so its my understanding the top would need to be machined as well. I it was machined to just clean up the surface (not warped) then the top would not need machining would still have to be shimmed. The how to rebuld your L28 book covers all this.

49 minutes ago, Wally said:

If the lashes aren't "100%" (whatever that means) what could happen? my machinist can't seem to explain the possibility to me

Human sacrifice, dogs and cats living together... mass hysteria!

Seriously, the wrong lash pads will mess up your camshaft. As you see from the group feedback, the smaller lash pad isn't making much sense.

Most stock lash pads are 0.160-0.170 inches thick, NOT counting the indent in the bottom, that actually rests on the tip of the valve. Aftermarket shims are available with or without these recessed bottoms.

0.12 or 0.080 inches does not make sense for any reground cam, they would have to be thicker than stock. Assuming stock valve heights of course. If you had really tall valve tips now, maybe thin lash pads make sense? 

These guys are my fav. AUD $ is way under both USD and CAD. 

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

I’d ask a few more questions of your machinist about installed valve height and what rocker pad to cam clearance he is measuring at. You know the .008 hot and 010 cold lash setting.

thanks. This is all over my head a bit. I am not sure whats going on. he did machine the head i know that much. i will drive up there monday and measure the lash pads. He keeps saying there are .120" but i am not sure they are.

i thought they were .160". Anyway i here is the place and link i bought them

https://zcardepot.com/products/lash-pad-cap-valve-rocker-arm-guide-oem?_pos=1&_sid=0f0a8f018&_ss=r

unfortunately it doesnt say what size they are just OEM...

Not everyone understands the geometry of the valve train so don't feel bad if it seems over your head. What we are wondering is what exactly was done to the head. If it was warped bad enough that the machinist had to take material off the top and bottom of the head -it will change the geometry of the valve train. If so, the camshaft is now closer to the valves and one would need smaller lashpads . There is also the possibility that the valves were sunk too deep into the seats during the valve job which would raise the height of the stem and put it closer to the camshaft.  That would not be good.  Just ask for an explanation of what was done and let us know 

Could it be that the valves are wrong? I could always be wrong, but wouldn't a taller valve require a thinner lash pad?

Maybe it's got L28D valves?

https://www.rockauto.com/en/catalog/nissan,1983,maxima,2.8l+l6+diesel,1211230,engine,exhaust+valve,5328

From what I've read the p79 head after a cut uses the 75 through 78 valves. I've not done this but here's a write up on that head mod. I'm no mechanic just a curious reads everything guy.

https://datsunzgarage.us/p79/

 

 

Edited July 23, 20213 yr by siteunseen