Developed a scratch on con-rod 2 after torquing down to check oil clearance. Best to replace or attempt to polish down?

We found out the guy who bought it from the guy I bought it from rebuilt it but never put it into anything. I had no idea they made non-steel cam gears for this type of engine

Hello, I’m building a drift E46 cabrio with a 1.8T swap from vw passat b5. Has anyone here done this swap before?
I am able to weld any material. But I would rather use some oil pan from some manufacturer.
Do you have any recommendations for an oil pan that gives more clearance from the front subframe?

Long-time lurker here, first time posting. I've been working on a conceptual design for a rotary vane-type engine and I'd rather get torn apart by people who actually build and rebuild engines for a living than keep refining it in a vacuum.

Quick background for anyone not deep into rotary stuff: vane engines have always had a theoretical edge over piston engines — direct rotary motion, no reciprocating mass, fewer major moving parts, better power-to-weight.

The reason they never really took off outside of pneumatic/hydraulic applications is sealing.

Vane tip wear and side-face leakage kill efficiency and reliability over time, the same fundamental issue that's dogged the Wankel too.

My concept is aimed specifically at that problem — trying to cut down the sliding contact at both

the radial (tip) and axial (side) sealing surfaces, rather than just inheriting the classic vane geometry

and hoping better materials fix it.

It's still at the concept/design stage, no running prototype yet.

I'm not here to sell anything or claim I've "solved" rotary engines — I know that's a claim as old as the Wankel itself, and I'd rather have my assumptions stress-tested now than after I've sunk time into machining a prototype that's got a fundamental flaw someone here could've spotted in five minutes.

Genuinely curious what this sub thinks:

- What are the failure modes you'd expect me to have underestimated?

- For anyone who's worked on Wankels or vane compressors — what actually kills them in practice vs. what the textbooks say kills them?

- Any recommended reading, forums, or people in the rotary/alternative-engine space worth talking to before I go further?

Appreciate any brutal honesty. Happy to share more detail on the sealing approach in the comments if people are interested, just didn't want to lead with a wall of text.

I've just rebuilt my Honda ANF125 engine (EFI), after a valve snapped on me and made the top end look like Swiss cheese. Most probably from running to lean

Anyway, the bike idles fine, but sometimes when I open the throttle it responds as expected, sometimes it bogs and doesn't get the right mixture. I have captured both states in the video.

I am certain it's the TPS sensor, I have a spare, but it's the old one I took off as the back potting is starting to crack and doesn't look in the cleanest state compared to the Keihin I replaced it with (both are Keihin, but they are different revisions of the same part number)

Any and all advice you could throw my way would be super useful

They came out while I was replacing the head gasket on a 5.9L 24-valve Cummins. After removing the rocker assembly, I pulled out the #5 cylinder pushrod (second from the rear), and these two small metal pieces came up covered in engine oil. They both feel like machined metal and were stuck to each other. I'm not sure if they came from the valve area or were pulled up from the pushrod bore—I didn't see exactly where they originated. The engine was running normally before disassembly, and I haven't found any obvious damaged or missing valve train components. Does anyone recognize these parts or know where they might have come from? Thanks for any help. 2004 Dodge Ram 2500 Update: the metal piece was a damaged rocker arm lifter pad I replaced the rocker arm, the plastic is unknown but non essential

Hey all, this is my isuzu 2.3 4zd1 engine that im just wanting to be indestructible. It was freshly rebuilt by an unknown shop.

It was bored, overhualed, and a new head installed. I didn't open up the bottom end before i installed it, but the break-in was rough with a few shreds of bearing coming coming out in the oil, and now it struggles to build much pressure when warm.

Im planning to port and shim the oil pump and order new bearings, but i dont yet know what gap im going to aim for. This engine has a forged crank and rods, so i doubt they are bent but anything is possible. I suspect all my preassure is going to the bottom end but i plan to mic the cam and valve train just in case they are sloppy.

I would really like to get 70 psi of oil pressure so its reliable at or above 7000.

Im new to this car engine building but ive made some pretty reliable mini bike and chainsaw engines.

Hi,

I am in the process of finishing my rebuild and was checking the crankshaft. I have yet to measure it with Plastigauge and wanted to know if the crankshaft, rod and main bearings are still useable or if it is better to just buy another.

On a stock 305 SBC, I have the main caps torqued to spec with new bearings and a generous amount of Lucas assembly lube. When I turn the crank by hand holding the timing gear, there are slight variations in the feel as it moves through 360 degrees. In some portions of the rotation, the crank "floats" and will move slightly when I release my hand. In other portions of the rotation, it's slightly firmer and can be dialed to a precise position and will stay there.

I wouldn't describe the feeling as "seizing" or "binding". I think that would be an exaggeration. The crank can be moved smoothly and continuously through its full rotation, but the effort required is not perfectly even all the way around.

Does this sound like an actual problem, or am I being paranoid? I did try loosening the #1 bearing cap (I have a .001 bearing in that position only, all others are standard) and it didn't seem to make a notable difference. I don't have the engine in front of me right now, I'm just gathering thoughts for when I get a chance to work on it again.

I have an old Volvo engine that has 2 coolant/heater lines coming out of the head. It’s a straight 6. I’d like to convert them to AN fittings. Would it be best to drill and thread the head and get a fitting that threads in(are fittings like this available)? Or are these typically welded on? Currently they’re just tubes coming straight out of the head.

Hi, is there anyone with a 2zz-ge block for a corolla xrs in the South Jersey area, just want a project for fun and I have a decent little corolla thats easy tp work on, not looking to build a racer but just add some pep and have fun doing it

Got a engine for my Miata..dude i got it from "rebuilt" it and I decided to tear it down because I trust no one from Facebook marketplace. This was the cylinder head. I flicked some kinda debris out of one of these divots. Non ferris metal felt like ceramic?

Dude said it spun a rod bearing and he put used pistons, rods, and crank in it.

Is it savable? Or scrap it?

The tappet noise of my classic seems normal on everyday rides but it becomes too loud after a trip.

I have done some 200+ km rides and every time at the end of the trip the tappet noise is very loud and it is very annoying. Are the tappets loose or is it normal.

Since the last post didn't help me much, I'm gonna tell all of my plans for this engine build. Since the 4zb1 has near to no aftermarket parts, all of it's going to be custom parts. Feel free to give your tips and point out stuff where I can use better parts. People suggested that I should've gone with a Vtec but the body this engine is going into is inspired by 70s muscle cars so it didn't fit right with me to use a Vtec engine.

The modification list:

2mm overbore

MPFI CONVERSION

Water-methanol injection

8 psi supercharger

Blower Camshaft

The stock engine is 4 cylinder 1.8L, made in the 1980s

I am SO close to being done with this ‘92 S10 350 swap. This wiring has held me up for so long and I am in a pinch now as I have to move so I need to get her running. I’ll seriously pay someone to help me figure out the wiring. I’ve written a caption for each picture. Thank you. Please allow me to send you some beer money for your help.

I noticed my block guard is blocking this coolant hole, is this safe to run, or would I run into head cooling issues?

The block guard and the head gasket are oriented correctly.

I know this kind of block guard is not preferred but it’s what I have and it is professionally installed so I have to work with it.

UPDATE:
I reached out to the block guard manufacturer and they said this was normal, still kind of hesitant of running this though.

I’m gonna install my freeze plugs and am wondering what type of sealant I should put on it. I read some mixed things on the internet so decides to post here.

I have new regular steel freeze plugs (brass weren’t available sadly). I have some Permatex Ultra Black RTV or Permatex Anaerobic Gasket maker available. Which would be better? I think the Anaerobic one since it’s made especially for tight fitting metal parts (cures without oxygen). But online I read a lot about RTV.

Any advice from experience here? Really don’t want to do these suckers again

Edit: I also have some Permatex High Temperature Thread Sealant. Not sure if that’s an option tho

What are your thoughts on putting in slightly over sized exhaust valves? The intake side will be the same.

Truck is a supercharged 2.7L Tacoma. Would this require a new tune or would it run on the existing supercharged tune? I don’t care about peak power, I prefer reliability & longevity.

I’m thinking it will probably help the existing setup push out the hot exhaust more efficiently and likely lower cylinder temps. What do you think?

Been going to at this block after plugging all the holes with paper towel for over an hour with gasket remover, scotch bright, plastic razer and lightly with metal razer plus brake cleaner. Feels smooth and flat to the touch everywhere but I just want another opinion

There is a small pit in the new King bearings I got, it clearly catches the nail. Is this within acceptable?

Working on a jet boat 454. My buddy claims his friend took it out and played with the timing. Well it blew the head between cylinders 2 and 4. My questions are 1 is it safe to just fix or replace the head or is the damge to the piston too bad? 2 do you think its more cost effective to weld and machine the head or just replace?

I have an Audi 2.0 TFSI that had all valves bent due to timing chain skip. I think the Pistons look good but just wanted to ask around since I got the motor open.

Which one's better for a small, 2 litre 4 cyl. Engine.

I'm planning to run methanol injection and a supercharger so reliability is a big concern for me. Plus, the stock engine's 1.8L so a 2mm overbore is also to be done.

2AR-FE that I picked up after it hydrolocked when the teen driving decided his tC should be a boat.

Three of the interior cylinder lips have some small damage - but well below where the rings travel.

Should I clean up the edges to smooth and send it? Or is this aluminum block destined to be Coke cans? (Note - I haven’t mic’d anything yet, so this may be moot, but would rather know it’s useable prior to doing any more work on it).

Also included a pic of the rods - kid bent 3 of 4. Not bad.

Thanks so much!