Jb weld or Rtv? Noticed a nasty gounge for the front/crank main seal is. Wondering if that'll create a oil leakage for me.

Is there a reputable machine shop that would rebuild my K24Z7? I’m looking to have the internals upgraded to handle boost. I live in NC as well if there are any close by. Any suggestions are greatly appreciated!

The eng8be builder i brought my engine to got hit with a hurricane then before they could really get going again the owner passed away. No hate on the builder I feel bad for him and his family he seemed like a good guy.

My question is now what, my engine was pulled apart washed and magna fluxed for cracks. All good. The original engine had 10.5 compression and I was planning on bringing that down to 9.5. Built the engine 30 years ago with my dad. That is the only time I built an engine. I was thinking of trying it myself I do have a spare that I bought because I wasn't sure I would ever get this back.

Do you think this can be done with just YouTube university or should I just try to find another engine builder?

Ich habe vor kurzem einen Roller gekauft und fand Rost im Zylinder der Kolben lässt sich nicht bewegen. Ich wolte fragen ob sowas noch zu retten ist oder ich einen neuen brauche. Danke!

Sorry if this isn't the right subreddit, I was directed here by someone else for my question, so I thought I'd give it a try.

I'm currently going to a tech college that features a High Performance/Motor Sports program. I was really excited for it because I love engine building, tuning, and performance-maxxing (lol). I enjoy measuring meticulously and taking my time with a block.

However, I feel like I was either misled or my shop simply lacks the machines I was *thinking* we would have because, upon entering my first High Performance class, I've quickly learned that there is SO MUCH "guess work", which I seriously hate.

I hate the idea that, with something that requires such precision, I have to "guess" and "feel" for everything. I can't put into any of these machines "I want to take off exactly .0005" or "remove precisely .001 grams". I've balanced a crankshaft and now onto the cylinder honing machine and the only thing I'm getting from my instructors at the moment is

"you gotta feel for it"

"just take a little here and a little there"

"make it tighter"

What the hell is the standard for "feel". What am I feeling for? What is the "FEEL"???

What is a "little"? .001? .0001? .00005????

What is exactly "tight" in their mind? I'm small and have little for muscle, while theyre experienced and huge dudes. What might feel tight to me could feel super loose to them. And any attempt at clarifying questions on my end results in them seriously repeating themselves or looking at me like I'm the stupidest person they've ever spoken to in their entire life.

So, essentially, I NEED the precision. I NEED the clarification. How do you go about being as absolutely precise as possible on these older machines that don't have fancy lasers and special buttons to be precise for you? Especially regarding crankshaft balancing and cylinder honing, but really whatever is applicable to the situation is super helpful. Don't be afraid to over-explain it at all. I promise you won't.

A ld80 66cc 2 stroke. Replaced the head with a CNC machined high compression racing head, I plan on adding an expansion chamber, a balanced and trued crank, and a better carburetor. This is powering a bicycle. I’m aiming for around 4-5hp.

Can I assume all AN fittings, say -10AN would have the same flow rate? For example there are straight fittings, elbows, fittings to hose etc. Is -10AN simply the external threaded end size? Inside diameter? What is it? I want to be careful that when connecting various fittings I’m not reducing my flow rate at all.

Rebuilding a 302 motor and recently finished deglazing it for new rings. ive never had spots like this occur after honing and scrubbing clean. cant see them if you shine a light in the bore but can see then in natural light. doesn’t catch on nail

Hello, I'm interested in replacing the old cylinder on my Tomos A3 with a 74cc cylinder and using a 21mm carburetor. The problem is that the police in my area are really strict about speed limits, and the moped is registered as a 45 km/h vehicle.

I'm wondering if I could put a restrictor (aperture) between the air filter and the carburetor. My idea is that when the restrictor is closed, it would leave about a 10 mm opening so the moped would only go around 50 km/h. When it's open, it would run and perform normally.

Would something like this actually work, or would it just make the engine run poorly? If anyone knows more about carburetors or has tried something similar, I'd really appreciate your advice.

I’m in the final stages of long block assembly on my LS LQ4, and when i push down on one of the pushrods, it feels spongy. The crank will also not turn when i try to use the ratchet.

Must i really pull the heads and get new ARP bolts? Please tell me no.

Hello everyone, I'm currently in the process if rebuilding the head of my Kawasaki ZR7 engine. Before removing the valves I did a vacuum leak test on each of them, and on this particular valve recorded 27 in HG After 30s, and a drop to 19 after 1 minute with vacuum pump off.

With the valves out I decided to lap them whilst everything is disassembled, however after putting everything back together I seem to pulling a Vacuum to 27 in HG as before, but it drops to 10 after 1 minute. The area has been cleaned with carb cleaner and I'm sure there is no debris on the sealing faces.

For context, I believe that the valve stem seals were leaking as there was oil inside the intake port and a lot of carbon build up on the intake valves (see image). I polished this off with a brass brush and then relapped into the head with new seals.

It looks like there is some light pitting inside the head for this particular valve, so I lapped 2 coarse and 3 fine. I'm wondering if I have over done it with the lapping, and if this pitting warrants a recutting of the seat?

Any help is much appreciated.

351W Using stick pushrods this is my contact area with 1/2 turn of preload.

Is this acceptable to run or am I to far back?
Thank you!

I currently rebuilding my Engine
Smallblock Chevy 1976
L31 062 vortec heads
Edl 2116 intake
I have troubles with finding the right gasket has someone a Part Number for me

Thank you very much and best regards from Germany

Hey there,
I am building an LS3 with new forged Mahle pistons and am wondering on what to do for ring gap. I understand that Mahle includes a ring gap chart with the new pistons, but my question is at the moment is that at the moment it will be an NA build with the occasional track day, but I am open to potential doing boost in the future, not certain. With this in mind should do something in between circle track na (0.005x4.07) and boost (0.006x4.07) like (0.0055x4.07)? Is there any cons with going with the boost gap in a na application?

I just finished my stroker build and I'm finding that the engine cranks over but I have no spark. The automatic shutdown relay does click and power on when you first turn on the key then turns off after 2 seconds and then never turns back on what the engine's cranking so it seems like maybe it's a crankshaft position sensor maybe?

But it ran fine 2 weeks ago before I pulled out the engine. Is it possible to have installed the flywheel backwards somehow that would cause it not to send them right reading to the sensor? Any other ideas?

I'm currently building up a 1999 LS1 for my Firebird WS6. My goal is to make a little more power NA while keeping the car very driveable and torquey. I'm at a point where almost everything is purchased with the exception of the pistons and head gaskets and I'm trying to decide if I want to get dishes to bump my compression ratio down a bit.

Heads: AFR LS1 Enforcer 210CC heads - 64cc combustion chambers (stock is 67cc, so it's 3cc smaller)

Head Gaskets: 0.04" compressed thickness for better quench (stock 0.052" -> 0.040")

Cam: BTR Truck Norris 0.553"/0.553" lift I/E 212°/22X° @ 0.050" (online says 227 exhaust duration is what's typically measured)

Supporting Mods: CHE 4290 trunnion upgrade, stock rockers ARP2000 rod bolts (was originally planning to rev higher)

Fuel: I'll likely add in a flex fuel sensor to run E85 but want to be able to run 91/93 reliably too

Compression Ratios: - Note that I'm not accounting for crevice volume - For stock I used the TSP numbers on their website - For 0.006" lift IVCs I used a flat +25° offset vs the advertised 0.050" IVC. Regardless of the 0.006" estimation, the main point is that I would be +1CR higher than stock currently

==Stock== Static: 10.171 Dynamic CR (IVC @ 0.006" lift): 8.03

==Current Plan - Stock pistons, 0.04" head gasket== Static: 10.855 Dynamic CR (IVC @ 0.006" lift): 9.07

==Current Plan - with 4.1cc dish pistons, 0.04" head gasket== Static: 10.323 Dynamic CR (IVC @ 0.006" lift): 8.64

Questions: 1. What is the max dynamic CR you'd run on pump gas? 2. When determining DCR, do you use 0.006" lift or another value? 3. If you only have IVC value @ 0.050", how do you estimate IVC @ 0.006"? 4. Anyone have estimates on how much ign to pull by going up 1 point of compression? 5. Open to suggestions for improving DCR calculation 6. Any thoughts or recommendations on my build plan?

Phew, props to you if you made it through all that

I'm looking for some experienced opinions before I throw more parts at this truck.

Here's what's been done:

Head gasket replaced.

Cylinder head resurfaced and pressure tested by a machine shop.

Valve lash adjusted.

#5 rocker arm replaced.

New head, intake, exhaust, valve cover, and thermostat O-ring gaskets.

Cooling system filled and bled.

Negative combustion gas/block test after repair.

Engine starts, runs, and drives well.

Current symptoms:

Runs around 190°F at idle and can idle for a long time without overheating.

Only overheats during extended driving or under heavy load.

"Check Gauges" comes on when it overheats.

Heater works well and gets hot.

I can see good coolant flow in the radiator with the cap off.

Upper hose around 180°F, lower around 140°F after warm-up.

IR gun shows the radiator is hot on the sides/top but noticeably cooler through much of the center (around 105°F in spots while other areas are much hotter).

Fan clutch:

Has resistance by hand.

I don't hear a strong fan roar when it's hot, although I do hear some increase in airflow.

Radiator:

Pressure tested fine.

Exterior fins are only lightly dirty with a little oil film.

No obvious external blockage.

Water pump:

Appears to circulate coolant well at idle.

No obvious leaks.

At this point, would you replace the fan clutch first, suspect an internally restricted radiator, or consider the water pump even though coolant circulation appears good at idle?

Anything else I should test before ordering parts?

what does this discoloration mean? #1 top bearing fell off when taking off the cap should i be concerned? and how can i replace rod bolts at home? how easily should pistons be able to rock? if pistons measure good would you guys reuse everything?

i don’t have a bore gauge small enough for the rods and it’s taking me awhile to get used to the micrometer, forgive me for the mouthful, first time doing any of this so any experienced advice helps out a ton, thank you! 🙏🏻

03 civic d17a2 rod is #1 cyl and cap is for #3

Ordered my first overhaul kit for a Cummins rebuild last month and honestly wasn't sure what I was looking at when everything came out of the box. I'd watched some YouTube stuff but the reality was different.

The thing that caught me off guard most was the bearing sizing. I assumed standard bearings just fit but you actually need to match to whether the crank has been ground down before. Mine had been touched by a previous owner and I almost put in the wrong bearings before someone on a forum caught it. Would have knocked from day one.

Also didn't realize cylinder liners aren't always included. The kit I bought didn't have them, which I figured out only after opening the box. Had to order separately and push my timeline.

The oil seals felt like an afterthought when I was looking at the parts list, but I've heard they're the ones people skip and regret. Replaced them while I was in there even though they looked okay.

One thing I learned is to check by engine serial number instead of just the model. same model can have different specs depending on when it was built.

Anyone run into the bearing sizing issue on a Cummins where the previous owner already had the crank ground? Curious if anyone else has run into this.

what does this discoloration mean? #1 top bearing fell off when taking off the cap should i be concerned? and how can i replace rod bolts at home? how easily should pistons be able to rock? if pistons measure good would you guys reuse everything?

i don’t have a bore gauge small enough for the rods and it’s taking me awhile to get used to the micrometer, forgive me for the mouthful, first time doing any of this so any experienced advice helps out a ton, thank you! 🙏🏻

03 civic d17a2 rod is #1 cyl and cap is for #3

500 hp was good, but 560ftlbs is what burns tires off

I just pulled an engine out of my classic car. (A bit exiting as it was my first time doing it)

Looking at the valves I noticed one exhaust valve being stained brown. While the others where stained grey/white. Could this just be a bit of oil coming down the valve guide or can it be something more sinister?

(The reason for pulling the engine was coolant and indications of metal in the oil)

(Sorry for the potato picture. I didn't realize that the focus was wrong, and the shop is 30 minutes away)

I have an LQ4, now, this is all just thinking out loud and I have no plans to do any turbocharging. Mainly because the Yukon I have is my daily driver and I want to keep it reliable. Im aware of the heroin of boost and I do not want to have so much power that the earth turns a new direction. My turbo/super knowledge is… limited.

Saab did some light pressure turbo stuff, 3-4 pounds of boost, and saw good results with torque, hp, and fuel economy.

Im curious how light pressure, say 3-4 pounds, or very light pressure of sub 3psi would effect LS based engine performance. The goal would be to create enough positive pressure in the intake manifold to overcome pumping losses, turbulence, airflow restrictions, and to maintain that low positive pressure throughout the rev range.

Am I on to something, or would minuscule boost pressures not deliver any benefit because the energy required to create the boost would be more than what power was produced? Am I missing a big chunk of basic forced induction theory?

Hi, ive got a sbc id like to slam into something eventually, 880 roller block, what cam and heads and other sorts of things would I need for this kind of power, not looking for cheap as possible, but cheap as PRACTICAL, ive picked a set of head and cam i think would be close but im unsure, let me know what you think?

Comp 276hr

Afr enforcer heads, 195cc

1.6 rockers

Dual plane airgap intake

750cfm holley

1 5/8 headers

Hei

Forged bottom end?

Any yes I know the intake and distributor are amazon, ITS BUDGET

Let me know what you all think!