My 1990 300zx Twin Turbo build by megaDan

7 minute(s) of a 731 minute read

Thanks for the tips. After a ton of searching I found 'Duplicolor Wheel Coating' in a matte finish good up to 250F. I did a test spray and the results definitely looked good. I'm crossing my fingers that 250F is sufficient for the timing covers. The only other clear high temp paint I could find was by Eastwood, but it's not readily available and would only provide another 20 or so degrees of safety.

I also picked up a can of the electric motor cleaner you suggested and it did wonders for the alternator. I still need to give it a little more scrubbing, but it made the hard part easy.

My plan for the weekend was to finally get the engine bay degreased and get some rust converter in the battery tray area. Saturday was pretty productive; I got all the gasket surfaces clean and the scored cam journal polished. I think this head is ready for install. I was also startled by how clean the top of the head was. It looks like it's never been installed...and aside from removing RTV, that's exactly how it was when pulled out of the car. I placed the head on a clean sheet of cardboard, wrapped it in a trash bag and tucked it in a corner on the workbench.

This was before I removed the exhaust valve cover RTV. So clean!

Also not bad.  

I spent a ton of very fretful time working on the headgasket surfaces. As much as I want to go back to a more tolerant composite OEM headgasket, I think MLS will be the most cost effective, easiest, and durable assuming the mating surfaces are adequate. I've been nervous about going MLS again, especially with reused heads but I checked 32 vs 60 vs 125 ra on a comparison gage and my heads feel like they're in the 30-40 range so I really should be OK. I need to stop worrying and order some damn gaskets so I can finish this project.

Saturday afternoon I sprayed the engine bay with GUNK Foamy and tackled the really bad surfaces with the detailers equivalent of a toothbrush. I was hoping the GUNK would be a spray down and rinse off type of product as advertised, but even non-greasy/oily surfaces still needed some help to really get 'clean' after a good rinse. It certainly did make gross buildups easy to dislodge with some gentle brushing. Following a rinse and a wipe with a rag and another rinse, once grimy, heavily coated surfaces are now clean and bone dry. Yay. Unfortunately its difficult to tell in the pictures I took. And I still haven't done a good 'after' photo as the engine bay is still masked. 24 hours after the degreasing I hit the rusty spots with a rust converter as a last ditch effort before hacking up the battery tray. My plan is to hit the bad areas with more of the black engine enamel and find a replacement cowl to prevent further water entry.

Grease free, but mask heavy. It really is starting to look nice.

I had a little more time Sunday afternoon so I began work on the much worse passenger side head. I figured it didn't make sense to spend time on anything else if the polishing didn't go well, so i started there. I used 800 grit 2000 grit, and finished with a 2500 grit sandpaper. The process was very tedius but somewhat enjoyable. My whole plan was to find a rotary accessory, but I struck out with each idea I tried. I ended up cutting 1"x1" squares of sandpaper and very gently applied them to the journal surface. I'd polish for 5 seconds or so, then clean the journal and clean the sandpaper and repeat. I knew the score marks wouldn't completely disappear without removing FAR too much material, but I had hoped they would clean up a bit more than they did. I am very pleased with how mirror-like the non scored surfaces turned out. They're smoother than the remaining journals. I'm a bit nervous, but I'll monitor them closely after an initial break-in. The remaining grooves just leave more room for oil.....right?

Before polish.

After polish.

After polishing, I installed the good cam from the drivers side head to try and get an idea of how much material I removed. A caliper on a diameter when trying to discern a .001" change is not an appropriate measurement instrument. So I installed 3 of the 5 cam caps, and left two off, one being a pristine journal, the other being the one I polished. a .0015" feeler passed easily on both journals. A .002" started on the good journal and entered pretty far on the polished journal. I got a .003" feeler into the polished one, so it's approximately .001"-.0015" larger than the other journals. I can't be certain that the wear wasn't present before I started polishing, but that's most likely mostly the result of my work. Given how little load I would expect the last cam cap to see, I don't expect this to be an issue. Is it ideal? No. Is it worrysome? Also no.

Checking cleanance

I need to order parts ASAP, finish the passenger side head, and get the block mating surfaces cleaned up. I think I've just about eliminated all of the questions that had been preventing me from purchasing parts. Time to get down to business....although this month gets busy, so my optimistic timeline is looking like end of October.

And because I can't sit still, I made my first all-grain homebrew on Monday. I got a Goose Island Bourbon County kit for Christmas but apparently didn't specify the extract version; so I got a box with 25lbs of grain. After spending weeks researching and finding some equipment on Craigslist I finally got enough courage to give it a try. I think an 8 hour brew day was more exhausting than 8 hours under the car. Jeez. Everything went spectacularly and I'm on track to hit ~13% abv! It was really cool learning all about the process, but I very much prefer the 2-3 hour extract brewing process versus the 8 hour DAY all-grain takes.

While the wort was boiling I moved the Peanut Butter Chocolate Milk Stout I had fermenting into a keg. I know it's not for everyone, but I'm a huge fan of everything PB, especially beer. I was nervous as to whether or not this was going to work; but to my surprise the initial tasting left me with exactly what I'd expect, chocolate, some sweetness, and a good amount of peanut butter. It's going to be a good winter!