I rebuilt this exact engine in my patrol 15 years ago in the driveway.. I wish this video was around then, actually RU-vid would’ve been great too.. loved the vid mate
Well done Jeff, love the fact that you're not one of those panel beaters who's done it for the last 30 years and make it look so easy but with you- seeing you learn as you go along and solving problems each step of the way is truly inspiring!
Hey Jeff, cooling your weld with air and water actually causes a lot of your distortion issues. Also when you make your patches, try and have a nice rounded corner, instead of 90 degree corners. The sharp corners concentrate a lot of heat, which causes bad distortion in those corners. A radiused corner will give you even distortion all the way round. And at the end of the day, you can't stop distortion, only minimise it, you'll still need to hammer and dolly 👍
Great channel Jeff, just started watching your 240Z series and will have to go back and watch some of your older videos. Like many others have said have you tried using a good heat sink behind the area you are welding. I use a copper plate to back my welds as it dissipates the heat very quickly and will not weld to the sheet steel. This way you can avoid cooling with air or water as they can cause the warping. I made my backing plate using a large copper pipe I found in a scrap pile, I hammered it flat to make a large copper plate.
Awesome tip on the plastic organizers. Sooo important to keep things lined up like that. In 2 weeks, or 2 months, I'll have no idea what when where anymore. This makes it a cinch.
I've read in some pages that people use flattened copper pipes as a heatsink in order to reduce heat in areas when welding. as a double i've used it as a brace in order to fill in holes since copper doesn't stick to welds
Hey man! just discovered your channel now through the 240z, just wanted to say love the idea of the sketch clothing, very original and keep up the good work! definitely entertaining stuff
When you weld in your patches use a hammer on dolly technique directly on the weld don't go crazy the metal will let you know if its enough this stretches the metal back because as you weld it shrinks, the metal gets drawn into the weld so you need to reverse this.
Next time when youre doing patch panels, dont cool the welds with air or water. Just let it cool naturally and take your time. With air and water, the metal might cool too quickly and it warps it.
Theres a guy here at youtube named Aaron Cake who is doing a restoration to his mazda cosmo. When he was doing bodywork and welding, he had issues with warping. He also used compressed air to cool the welds and he discovered that the air was actually the reason for the warping.
You have probably heard all the alternatives, but my personal favorite is to pre-heat the metal so there isn't such a sudden change in temperature and let it cool down slowly.
As above, don't cool anything and you can also preheat/post-heat. You want it to cool as slowly as possible. Also be very careful when grinding back welds or using a flap disk, both will create enough heat to warp panels.
8:06 just a tip but when cleaning the metal for welding, don't use a strip disc or grinding disc, it will remove metal and thin it out, which makes welding harder without blowing it out later. Instead clean with a crumpet wheel or wire wheel which won't remove material.
Great build, keep it coming! Are there still honing marks in the cylinders? If so then you might get away with just replacing the rings. Get a copy of "How to Modify Your Nissan & Datsun OHC Engine" by Frank Horowitz if you don't already. There are lots of good tips and tricks in there. Regarding the cowl panel rust, the car came stock with vibration damping material bonded to the back of each side of the panel - exactly where you had rust. These get wet and hold moisture against the metal causing it to rust.
Ahh, that explains the rust. As for the engine. I am actually using that book at the moment. The bores look good from what I can tell. No visible scoring, and nothing that I can catch a nail on. You can still see some light cross hatching as well. I am still working out how far I go with the rebuild. I plan on putting a mild cam in it. I am contemplating shaving the head to increase compression, but I still need to find out if I can find some shims the correct size to raise the cam, and keep the chain tension the same.
So just have it re-honed and go with it...although boring it out and installing larger pistons will give you more displacement and possibly more power. Which block number do you have? 280z N42 blocks have quite a bit of meat left around the cylinders. Later 280zx blocks have thinner walls. I'm running an N42 that's been bored .030 over.
I have an N54 block with a P90A head. I am not really interested in boring it out. I am trying to keep it simple and affordable for others to replicate and do at home.
Lightly hammer and dolly your tacks while they're still warm to allow the metal to relax and go back to shape. An old hot rodder trick that has worked for me.
Hi Jeff, If you actually look into safety using grinders they state not to wear gloves as if you get the glove caught the grinder will pull it in plus you fingers/hand. Always leave the guard on the grinder, use the recommended safety glasses and most importantly use both hands which means clamping what ever you are grinding. They are dangerous tools.
A good day... new Jeff video including a shout out to Binky and... a new Binky video - yay! Only problem now is do I watch Binky right away, or do I wait and savor the moment? BTW - could used your input on the plastic bags a while back...
I know! Then it's withdrawal time until the next episode. Still, I've got your videos to look forward to on a Friday - just up the road from where your engine is being built so, happy to help if there's anything I can do. Now if only I'd get my own project moving...
If you have a flat piece of sheet metal to weld maybe clamp it to a heavy aluminium plate (10mm) which helps spread the heat and prevent warping. The labelled box is an excellent idea..I thought I was watching Tom's Turbo garage for a second there....That L28 engine is a much simpler engine than the Porsche that is fo sure, should go together smoothly
Wish I'd done the labeled plastic boxes instead of bags, like you found on the 911, I now have a big box full of random nuts, bolts, washers and broken, oily bags.
Yep. I had the same issue with the body bolts on the Porsche, and it was a nightmare finding the right ones again. The boxes are such a simple idea, that just makes sense.
Very hard not to warp a panel like that using Mig welding, I'd use oxy welder myself which allows you to reshape the metal afterwards, but probably takes more time.
What gauge is the sheet metal being used for the patches ?/ Are yo using a MIG or a Flue Core welder ? I have a 69 Fairlady withthe typical rust sppots that I need to fix C
The running joke was these things were made out of recycled beer cans but most folks figured out quickly the sheetmetal was thin when it started rusting. Am curious how the car in general compares to the Porsche and body panel thickness would be another observation point. Glad to hear you're going to rebuild the motor yourself, will rewatch those episodes over and over, have you thought about trying to get a diesel crank and do a stroker?
I have thought about the Diesel crank, and making it a 3.1, but I am not sure if it is worth the stuffing around. As I want to do it all myself, except for a little bit of machining, I want to keep it a bit simpler. I was looking at shaving the head to raise compression though.
Dont feel bad, I run the edge of my grinder across my thumb between the 1st and 2nd joint, went down about 1/8 inch, lucky I didnt take off my thumb, happened 25 years ago, still wear the scar today.
Funny thing is I didnt feel it when it went into my thumb, I looked down and seen this perfect grind slot, and it didnt even start bleeding for about 30 sec. But I believe I was in the end, lucky not to lose my thumb. It made all the way to the bone and stopped, but not due to the bone,and not due to myself, it was only luck.
the same reason people installed small block chevys in jaguars. well, aside from the gain in output. your straight six looks like it was due; can mrs. jeff do a bit history on that engine platform?
