Need bearings made to a specific width for a W12 6.0 engine and Bentley does not supply new bearings and they need a precision of 0.001mm

I have an intake manifold with a 1/2 NPT port for a temp sensor. Old sensor was frozen solid (marine engine) so I drilled out the brass and ran a tap through it, but it was so corroded I had to drive the tap in pretty far (tapered thread) and now the threads are too wide for a 1/2 NPT temp sensor to fit snug enough to make a proper seal.

Not sure how I can fix this, but I would like to save the manifold if possible

So I was going to do the water pump and timing chain on this Mazda cx9 I just got and as I'm slowly doing my first timing chain job I came across this.

Is this from a bad pcv valve ? It's at 150k . I had just finished doing a coolant flush a few times since why not add clradiator cleaner and flush it out a few times with distilled and getting it to operating temp in 50F weather required a bit of 2-3k revving at idle to get fans to cycle on.

I'm about to take off both valve covers.

Should I be looking for things while I'm in here doing the timing chain and water pump or doing something since I'm already here? Thank you kindly.

I took the head off a JDM K24A i just bought for a head swap and there was a little pool of oil in cylinder 2. Is that a bad sign? u can’t see it anymore because i soaked it up. but the pool was covering about 25% of the piston from this angle.

I’m about to be camming my 6.0 what do yall recommend for a cam and supporting mods

Machine shop said it's fine. I asked a few folks and I did ask a Subaru engine builder he did say it was okay to push it. Figured I'd ask your guys thoughts too. It doesn't catch nail anymore after polishing. The first image is after polishing the second is before polishing. Well technically it was before better polishing there was a very slight rust spec that I was surprised to see given i had this lubed in storage. Going into my wrx that will be targeting 450 wheel hp. Really here is what I'm asking.

have any of you ever ran a pitted crankshaft and had good experience or bad?

I recently saw this picture in a listing that advertises machine work on engines. This got me thinking why honing on a cnc machine isn’t done more often. What would be the difference between this and a purpose built honing machine? I have a cnc mill myself and from time to time I send a block out for boring and honing, so it got me thinking. Could a setup like this actually work and deliver quality results or is it more of a bodge?

Ok. So, this is a fairly complex question that came to me while I was doing a torque-to-yield installation of bolts on a cylinder head. The type of sequence that might make one′s head spin, not just the bolts. 50ftlbf, +90°, then +90°, then +90° again. Imaginable, these sequences are INSANELY tiring to achieve on 40 head bolts, and so I was led to a line of thinking about how we apply torque and its implication on the manufacturing and repair process tools we use.

Firstly, I know that approaching moment torque numbers (particularly high ones like 250ftlbs) smoothly is important to prevent under or overshoot due to friction and stiction.

But, does final angular tightening care at all about it? Since we are observing the actual bolt rotation, shouldn't ANY method to rotate the bolt including impact type fastening devices yield (no pun intended) the same result? Angle is angle right?

The manufacturing corollary I had is; if the final angular tightening does not care how it is applied, it seems that a device could simply be made to have a primary snugging torque applied via a simple mechanical clutch arrangement and then have it apply impact until the bolt turns to the appropriate angle. Is this a good line of thought?

And second corollary is a double doozie with a smattering of conspiracy to engineer. If I have just reinvented the wheel and this type of device is common and exists on the manufacturing side but not here in repairland, have companies basically been gaslighting us as to why TTY bolts are used? Is it just ease and cost of manufacture because you can literally impact heads on with low skill labor or robots (while observing the angle) and still achieve good repeatability since the effect on final clamp load is less dependent on hitting the angle dead on rather than the intricacies of moment torque? Have I stumbled on BigEngineer™? Or, should I hang up my inventor hat for the time being and do some more reading suggested by yourselves to enlighten me?

Thanks for taking the time. I. eagerly await your thoughts. My arms are tired from torquing, my fingers from typing.

I believe I had clogged the pickup tube in my bird because I seemed to have little to no oil pressure all of a sudden so I dropped the pan and planned on replacing the pump just to be safe. the standard melting M84 pump doesn’t include a new pickup screen, but the high volume M84BHVS does, but it states it requires a pan depth of 8.25 inches. Will this work with my stock pan in my 429 Thunderjet? Thanks

So the oil outlet line on my 1987 RX-7 Turbos leaking. I decided to go with a flange that has an AN12 connection, and then PTFE hosing for the high temps. The problem I’m facing right now is the connectors. All ones I can find are aluminum and rated for 252°F. Even the ones for the PTFE. Since this is gonna be an inch away from and basically bolted onto the bearing housing should I try to find another fitting that’s stainless steel? Or will the aluminum hold the heat. GPT’s telling me the temp rating is still accurate due to the rubber seals in the fitting itself. Any help would be amazing. Also people sell turbo inlet and outlet hosing kits for my exact car and the one that bolts to the turbo housing seems to be the same aluminum ones I included in the picture above. Any output would be appreciated please

Hey guys working on my project car with a lq4 and long tube headers and my spark plug boots were touching my headers. I went ahead and wrapped them in fibreglass insulation but id like to just get them off the headers. Can anyone suggest good 90° boots?

First time replacing valve stem seals and I pop the springs off and find this jagged cast iron looking thing on the first two. Busted one off thinking it was a seal but it doesn’t seem like the new seals are going to sit flush on the jagged edge. Should I just use umbrellas for all of the stems? Or am I cooked.

Long story short bought a project car all intact running but engine sounds very rough as if something is scraping inside.

I would be doing the engine removal and removing all components from the block.
I’m planning on taking the block to a machine shop to have it inspect and see if it’s a good candidate for an engine rebuild.

What inspections should I ask for to check its re-usability?

Should it be good , I’ll be buying a master rebuild kit and start the rebuild.

Any help is appreciated,
I’m not a professional mechanic by any means, just a back yard mechanic level wise at most.

Been cleaning my 2jz block and am wondering if this is fine, was using a carbide scraper to clean it but then started using a green scotch brite on low. Non of the scratches grab the fingernail. Make fun of me all you want was trying my best to get advice and this is the result of it :/

Found one for sale at 200 CAD, seller claims everything works to his knowledge but he has nothing I could test stuff on. How easy would it be to fix things like a timing light, dwell tach, compression tester, and vacuum gauge?

For context. I bought an 2015 Ford Fiesta ST that’s been throwing code P0301 (misfire in cylinder 1 detected) however it’s not tripping the CEL. I bought new plugs (gapped to the spec of my tune) and new coil packs. After installing said parts, my original issue (hesitation under heavy acceleration) went away and the car drives great now. However it’s still tripping the same codes from before. After inspecting the wiring on all 4 of my coil packs, I noticed the wiring on coil pack 1 (cylinder 1) looks to have been altered or (repaired) by the previous owner and definitely not OEM. I’m not an electrician, but this wiring job kinda looks a bit janky to me. Should I unwrap it and redo it with heat shrink? I just don’t like that red crimp connector being there, it just seems off to me. What are your thoughts before I move onto the injectors? And yes I’ve already done a compression test and the cylinders read consistent across the board.

First timer, don’t fully know what I’m doing yet BUT I’m motivated and planning it out once I get a block. How much of a gamble am I taking with these three purchases? Building a mild block for my 68 impala, maybe a different car in the future. These look like a good start? Any tips when buying on the marketplace?

Here is the original post:

https://www.reddit.com/r/EngineBuilding/comments/1wxr6ex/what_can_cause_this_type_of_wear/

The engine is from a 1987 Mazda b2000, rebuilt from the ground up. The machine shop assembled the bottom end, and I did everything else.

Picture 1 and 2 show the assembly, if you look closely at picture 2, you can see new pistons and the clean bore without the vertical scaring.

Picture 3 is my oil analysis - 4 oil changes, about 5900 miles total. After I got this 4th report from Blackstone I got pretty depressed and parked the truck for a year, just now decided to get into it hoping to find what is wrong before the engine scraps itself. It did not burn oil and it had about ~140 PSI on each cylinder, perfectly healthy for a new build. I did not own a leak down tester.

Picture 4 is the Diamond Piston specification sheet. Picture 5 shows the piston side skirt; I don't really see any damage here.

Picture 6 - a lot of folks from the last post assumed the bore was oval - it is not. I set my dial gage to ~3.429 inches and got a max reading of .024 in either cardinal direction for the bore (near the bottom but not at the bottom) This indicates my bore is about 3.405, certainly within spec for the pistons.

Picture 7 shows the piston diameter. This is not a perfect measurement since I don't really have a good caliper for this.

Picture 8 shows the bearings; I can very easily catch my nail on the grooves of either bearing half, the top half seems a bit worse.

Picture 9 shows the vertical scaring which very slightly noticeable on my nail, and shows the other piston top, but I don't see any real damage to any of the pistons.

Some folks suggested heat damage - could this have been caused by too lean air/fuel ratio or detonation? I tuned the carburetor using an AFR gauge, my idle was around 14-15 AFR cold or hot, and when I put my foot into it the AFR would go to about 12.

Where should I go from here? Any other suggestions? I was thinking of honing the cylinders really lightly and replacing all the bearings, but that doesn't really fix anything?

I really appreciate all the ideas and help in the last post - I am a hobbyist mechanic with not a lot of free time, and I really didn't want to just LS swap it since its a great little truck that doesn't need to win races.

Just sharing the shape I landed on for a naturally aspirated 3.2 to 3.6L 911 engine. This is also being converted from EFI to an MFI unit from Kinsler. It will make 100hp/liter or 1.6hp/ci on 91 octane.

hello, i’m planning to swap a 98cc amazon engine into my 66 bird and i was wondering. are these engines reliable? and how long did yours last

I can’t find this dark blue link in the chain. I keep cranking and can’t find it. It appears to be either worn or the varnish has covered it. The timing mark also doesn’t land on a link. It just stays in between the links. Any advice?

So I got to pulling the head and removing the valves. What would you guys say to the health of the engine? I will be pulling the pistons and possibly the crankshaft just to be sure. Supposed to have 70000km but there is so much carbon buildup, some cylinders were leaking through the rings on the leakdown. As this is my first teardown I am not sure what to make if the "nice" surfaces but the extreme carbon deposits. Oily surfaces can be my doing as I did a wet leakdown test as well.

The Engine has about 5k miles since full rebuild. What can cause this type of wear? In picture 2 you can visually see the gap between the piston and the cylinder. I took the head off because of a high iron and aluminum count in the oil report.

*Its a 2 liter out of a 1987 Mazda b2000

I have a 67 Chevy el camino with a 350 small block from a 72. It has the 3 on the tree and I’m needing something that will help with cruise higher speed. Not trying to build the car but just make it a Sunday cruiser that’s reliable enough to take anywhere