[Valve Lash Clearance Oddities]

Ah I see, it appears it has been reground. I took some crude measurements with an analog caliper yesterday and I measured the following:

The intake base circle and overall lobe were 30mm and 38mm respectively and the exhaust were 30.5mm and 39mm.

 

My measurements are probably a half mm off but with that the lobe lift would be about 8mm on intake and 8.5mm on exhaust.

 

With that, I think I'll set the lashes to about stock as you said and adjust if I notice anything odd.

 

[Valve Lash Clearance Oddities]

You guys are right about the units, I had them mixed up. My measurements were actually inches, not mm. The unit labeling on the gauges are a bit confusing but I see where I misread it. 

 

I added a few photos of the cam and lashes. All the contact patches on the lash pads are pretty even and seem to be a healthy distance from the edge. You can see a few of them if you look closely at the picture with the 'E30' side of the cam.

[Valve Lash Clearance Oddities]

3 hours ago, NewZed said:

One "trick" to increase cam lift is to run tighter lash.  But it's dangerous, if a valve doesn't close completely it can burn/warp.

 

Another possibility is "sunken" valves.  Early gasoline had lead in it which lubricated the valve seats.  When the lead was removed valve seat wear increased dramatically.  It's not uncommon to find sunk valves on 240Z's, as I understand things.

 

So, could be intentional, could be valve seat wear.  

 

 

 

Now is there any relation to the ratio of exhaust/intake clearance? Say the PO wanted a tight intake lash but left exhaust near stock sizes. Does having a clearance difference for intake/exhaust of greater than .002mm have any side effects?

[Valve Lash Clearance Oddities]

I finally got the chance to take off the valve cover and check the valve lash clearances and I noticed a strange consistency with my measurements. I have measured every exhaust valve clearance to be exactly .009mm and every intake valve clearance was between .004-.006mm except for one. The one valve was too tight for the smallest feeler gauge which was .004. 

 

To measure, I used a feeler gauge to feel for the highest gauge where it could slide between the cam and the lash pad while the lobes were facing straight up. This was also done with a cold engine.

 

Now, I know the stock clearances are .008mm and .010mm when cold, but my engine has been modified. I am unaware of the exact specs, but my camshaft (E30 Japan) says "Americam 060 1" on the end of it and the PO stated it had been bored/ported at some point. Regardless of the modifications, the clearances should be much higher than .004mm-.006mm on the intake valves, correct? The only reason my awareness has been raised is the consistency of my measurements. Could there be a reason the PO or a previous tuner to have set the intake clearances that low? Or were they likely properly set at one point, but over time have all evenly deteriorated to their current state?

 

Edit: Car is a 1973 240z with an L24 and E88 head

[Frame rails too far gone to repair?]

12 minutes ago, primaz said:

 

My car did not have rust or issues with the stock rails.  I used Dando's Automotive that specializes on Z cars; they have two ways of doing their custom frame rails.  My Red 240Z used their "U" shaped steel rails where they are boxed by welding them both under and inside the car.  Now most of the cars they do they use an already boxed rail and just weld that on the bottom of the car which cuts the amount of labor a lot.

 

As others have said it appears your car can be repaired but it does sound scary to me that you said, "window gets pinched to the door frame"?  On Z cars until you bead blast the undercarriage and the rest of the body you will never know where all the rust may reside.  I would really recommend you check the more common areas of rust to see if you can tell the conditions of those areas to decide if the cost is good.  The areas I typically see is the rear rockers before the rear wheels, the rear hatch (when you open the hatch look carefully at the channels and seams), bottom of the front fenders where often the drain plugs get junk preventing water from escaping.  Z cars are uni-body so no frame but they can be repaired it is just how extensive the bodywork is required.  If you feel the car is a good buy, fix the stock rails first and ideally if you are ready to do the entire bodywork then bead blast the entire car and see what areas might have had hidden rust.  Then fix those areas and if you can afford it put the rails I did as that is great for performance and safety.   

 

Yeah... the door may be a bit worrisome. It needs a decent shove to get it to shut completely. The chrome on the door window gets pretty snug with the chrome on the side window. By pinched to the door frame, I mean it will sometimes not sit flush at the top unless closed a certain way, if that makes sense. As if the door is mounted just slightly too high. The current owner claims the PO removed the door to repaint it and didn't assemble it correctly.

 

I usually check the typical areas for rust. The rear rockers had some bubbled up areas but no holes. Hatch channels looked great and nothing under the battery tray. The only active rust I spotted was between the passenger foot well and firewall area where I could pick off flakes of rust. What worries me is what else may be underlying that I couldn't catch. I was hesitant about the car already but it seems clear I would be better off finding a better one unless I could significantly drive the price down. I appreciate the info.

[Frame rails too far gone to repair?]

2 hours ago, primaz said:

It should not be that expensive to have a good body shop install those Z car depo type Sheetmetal but another option while more expensive it better if you build the car for more high performance.  I frame railed my 240z which provides a visual that looks like the stock look but provide incredible strength and even more than many roll bars.  A good body shop or repair shop that can weld could do this somewhere between $1500 to $2500?  FYI, besides the stiffness this saved my life and prevented my 240z from being totaled; I got rear ended by a car while stopped in traffic and the unibody was undamaged even with a hit from the rear from a Prius going 50 mph!  Without those rails the car would have been totaled for sure.

Thanks for the pics and message. Did you use the Z Car Depo style sheetmetal or did you have a shop custom fab the metal? I may do just what you did and look into having a shop upgrade it for higher performance.

 

The only thing I'm concerned about is the drivers side frame rail is rusted as in my pics and the drivers side door just barely not aligning. It can be tough to close and the top of the window gets pinched to the door frame, presumably from the frame causing the body to bend in a bit.

[Frame rails too far gone to repair?]

5 minutes ago, jhm said:

You can purchase ready-made frame rails and floor pans from vendors like Zedd Findings and Bad Dog Parts.  If you don't mind fabricating your own pieces, and you have access to the right equipment, you can make those pieces for the cost of the raw material.  

 

Too costly?  Only you can make that decision for yourself.  The only thing I can say with 99% certainty is that you will discover many more "issues" the deeper you dig into these 40 year old cars.  FOL.  If you're unfamiliar with the S30, I'd suggest doing a lot more research on them before dropping a bunch of cash to buy one.  However, I can say that $8500 will get you a pretty nice 280, especially if you expand your search to include the west coast, the southwest, or any other 'dry' climate areas....that's usually where you find the best buys for rust-free cars.

 

Not trying to be a big downer, but far too many people buy a Z for all the wrong reasons, and without a full understanding of what kind of project they're getting themselves into.

 

I totally understand. I've been doing a bit of research on and off for the past 4 years or so. I'm ready to do some work but nothing as serious as having to cut and weld new frame rails as well as god knows what else goes bad. I'm out in CA so I've been keeping my eyes out for low rust examples but most at least have some.  I expect to drop 8-10k on one and spend at least another 10k over time getting it into the condition I'm satisfied with

[Frame rails too far gone to repair?]

Cross-post from Fabrication/Welding. 

I'm looking at buying this '75 280z. The biggest downside is one of the frame rails has abut an 18" stretch of chewed out metal. Here's what it looks like https://imgur.com/a/TkbKOEo.

Are the rails too banged up and rusted to be repaired? And would repairing them bee too costly? Currently the owner is asking 8500 for the car. The only other rust is a little bit in the upper part of the passenger footwell/firewall

[Frame rails too far gone to repair?]

I'm looking at buying this '75 280z. The biggest downside is one of the frame rails has abut an 18" stretch of chewed out metal. Here's what it looks like https://imgur.com/a/TkbKOEo.

Are the rails too banged up and rusted to be repaired? And would repairing them bee too costly? Currently the owner is asking 8500 for the car. The only other rust is a little bit in the upper part of the passenger footwell/firewall

 

[Passenger fender replacement for '74 260z S30]

I'm highly interested in buying this 260z I found on craigslist. There is nearly no rust aside from some surface stuff on the hatches. It's a pretty clean car but there is a big dent on the passenger side fender. The current owner says it was (likely) a parking lot mishap from the previous owner. My question is how much would a replacement passenger side fender cost for a 260z? How much would it cost to replace it? Thanks!