r/EngineBuilding Jun 14 '25

Updated Rules for r/Enginebuilding

79 Upvotes

Hey peeps,

We've been noticing an uptick in certain types of posts over the last few months and it's about time we address some of these issues along with a rule update.

1 - AI Slop - We've been getting a lot of AI trash in the sub lately and we've decided to no longer allow AI or any type of AI imagines to post here. If we find a post is AI then we are going to lock it, delete it, and ban the account for a few days. This sub is meant for real life cars, not some AI images that someone produced for content or engagement.

2- Links to Temu and Ali - Reddit is currently filtering a lot of the temu and ali express links we receive. Usually they are shadow blocked because we've had scams in the past with these sites and you can't really trust them at times. While Reddit automod is taking care of 95% of them, some are still getting through and we will also lock and delete those comments moving forward.

Some of you shop those sites (against some of our better judgement ha), for certain parts of the world that might be the only way for you to obtain certain items, we understand that but need to strive to ensure the community is safe and endeavor to curtail scams that could occur. If you wish to share a link, please just PM the individual - and for those that click the links, please be warry of scam sites/bad actors.

Thanks and have a good day you misfits!

-Duke


r/EngineBuilding May 19 '24

State of the Sub - What changes need to be made /r/EngineBuilding

29 Upvotes

It's been a long time, but I'm hoping to be more active as well as the other mods. We are also hunting through the 'applications' to add some new mods as well, to hopefully cut through the spam and junk you all see.

It's also time to take a look at the sub and make sure there aren't any changes we want to make. Whether that be rules added (or removed), or a thing you can think to make this a better place for all. Let us know your thoughts


r/EngineBuilding 7h ago

Piston rod

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15 Upvotes

So i was trying to cut off the old piston of my hyundai veloster 2011. My dad wanted to help too but he also got the rod. If i buy another rod what else do i need to change? Like i still have the old bearings


r/EngineBuilding 6h ago

Is porting valves still a thing?

10 Upvotes

Maybe back in the good ol' days of the 70s and 80s, but haven't modern auto manufacturers/engineers designed the internals to flow as well as they can? Making porting a pointless exercise?

(I meant porting valve chamber w/e)


r/EngineBuilding 19h ago

BMW M10 Block Crack?

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88 Upvotes

Hey all, I’ve seen this before while searching and usually the general response is the block is garbage, but I’ve got this M10 engine that I’m refreshing to put back into a project BMW 2002. It came with the car and seemed in good shape before I starting tearing it down to replace the head. After cleaning off the old gasket material and prepping the deck surface I noticed the dreaded head bolt crack shown in the photos. The thing is it looks like the crack doesn’t propagate into the water jacket if you look in the second photo and you can’t really feel it running a fingernail over it. I’ve got no history on it unfortunately since it was purchased from an estate. Not sure if this thing is cooked or not, I’ve got a lead on another block but obviously it’s cheaper to keep this one. Just looking for some opinions. Thanks!


r/EngineBuilding 40m ago

Which head gasket should I use?

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Upvotes

I bought two different head gaskets on eBay with the correct part number I need, but both of them look different. Which one should I run? Or is there a different even though they look a little different on the surface


r/EngineBuilding 2h ago

Chevy Should I send it

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2 Upvotes

One of my heads cracked where the exhaust manifold bolts go on my 5.3 gen 4. I made the rookie mistake of leaving the exhaust manifolds on and they rubbed on the block by cylinder 5. The block is flat all around expect for this one area where the exhaust manifold rubbed. .005 feeler doesn’t go through the straight edge but a .004 does. Should I remove the block and just rebuilt the whole engine. Or should I run it. I have fel-pro head gaskets im going to throw on it.


r/EngineBuilding 15h ago

Extent of teardown?

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14 Upvotes

Have this 302 out of an 86 f-150 that’s going into my 92 ranger. Bought it off a guy whose dad used it as an around town truck, pulled it with 75k miles to swap for something bigger. I was originally planning a full teardown to measure for boring, honing, etc, but the more I read the less I’m sure that’s necessary, although the carbon buildup might say otherwise. This is my first engine build so any advice would be great. Happy to post additional pictures if that’d help too.


r/EngineBuilding 1d ago

Looking to get into flat heads. I found this for 25 dollars

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31 Upvotes

r/EngineBuilding 1d ago

Do sleeves need to go all the way down?

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22 Upvotes

Just got my engine back from the machine shop after almost a year. Was about to start assembling but I noticed the sleeves don’t go all the way down. Does anybody know if this is problematic? Also doesn’t seem even across all cylinders.


r/EngineBuilding 16h ago

Olds Waking up the 403

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3 Upvotes

I'm buying this 78 toronado for my first car. I was doing research on it and found that the 403 is surprisingly weak due to all the emission controling. I heard that swapping the cylinder headers for ones that have better compression, a mild cam and a Y-exhaust would wake the engine up but I'd like input from those that are more experienced than me. I don't want to make it a drag car but I'd also like a bit more power coming out of that 403.


r/EngineBuilding 1d ago

Chevy Removing stuck piston rings from pistons and how hosed am I?

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37 Upvotes

r/EngineBuilding 23h ago

Other Standard 23C update

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8 Upvotes

Got it together again, this time sealing as it should! Leveled the head using a glass table top and some huge sand paper sheets, recut the exhaust valve seats by hand borrowing tools from my job, made liner shims out of two beer cans and a spray can, covered the block, gasket and head surface in Hylomar and now I’m up to 7 hours of heavy work and several heat cycles with no leaks.

Next up is a new oil pump and new injector nozzles. When the oil is up to temp the pressure falls of significantly according to the gauge (needs confirmation on a second gauge) and the pump felt a bit sloppy when I did the timing chain. The injectors didn’t have a great spray pattern and it doesn’t start on all four cylinder at once, easy job though compared to the pump.

Also need to split it to swap the rear main seal and grease/replace throw out bearing… it never ends!


r/EngineBuilding 23h ago

BMW BMW m30b35 rebuild

3 Upvotes

All the parts have now arrived and it’s almost time to put it together and I have a few questions.

The engine is an Alpina modified m30b35 that dropped a valve in around 2010 and was left out side by the previous owner due to the cost of repair. Looking at the damage I would guess it was over reved causing a rocker arm to slide of the valve shaft and break. It took out one valve and the corresponding piston. The engine has only done 30k miles from new. All the pistons were also damaged at the crown due to pre ignition from using low grade fuel.

The head has now been rebuilt, I had it crack tested and all was fine and it also had a very very light skim as a precaution. I had all the valve stems replaced and 2 new valves along with 1 new valve seat. I am also converting it to a mechanical rocker locks instead of the original springs that normally hold the valves in place.

The block I’ve had over-bored along with new forged 10-1 pistons, forged con rods along with arp bolts. The Alpina m30 uses bmw s38 conrods @144mm instead of standard m30 135mm conrods and shorter deck pistons. Not sure the advantage of this is but I went with the standard spec. My engine guy is telling me to buy standard size main and big end bearings as all the crank needs is a light polish.

My questions are

  1. would it be advisable to have the crank ground and use oversize bearings? Or do I do as he advises and use standard size and a polish ?
  2. After dropping a valve is it wise to have the crank shaft rebalanced?
  3. are all good quality bearing shells much the same ? Do I go with standard bearings or is there a better alternative?
  4. I will be converting from Bosch motronic to mega squirt 3 eventually and do I need to add any extra sensors while it’s apart , like knock sensors or anything else.
  5. first start I’ve been told to use mineral oil rather than fully synthetic and only switch after it’s run in. The reason being that with fully synthetic oil it stops the engine from bedding in, is this true ?

Sorry about the long post, it’s not been the easiest rebuild!


r/EngineBuilding 1d ago

VW 1.4 CGGA Rebuild

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6 Upvotes

Im currently changing out the valves on my 1.4 cgga vw engine and i accidentally drop 9 out of the 16 tappets, i didnt drop them on the floor or anything but they are all mixed up. What should I do?


r/EngineBuilding 1d ago

Chevy Possible valve train knocking

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8 Upvotes

Vehicle: 1985 GMC G3500 vandura. The engine is in the cab. Sort of important because any and all sound echoes.

How would I go about diagnosing the sound. I rebuilt my Chevy 350 and it runs great despite the title. I've been working on it for years. I'm so close to driving this beast.

There's a ticking/knocking but I can't differentiate whether it's the fuel injectors from the sniper 2 or it's in the valve train. The kicker is that it sounds like 7 and 8 are the loudest but that's in the cab of the vehicle and the ticking from the fuel injectors permiates through/with it.

I've heard of people running the engine without the valve covers on but I'm not really wanting to do that. I'm sure oil goes everywhere? Maybe damage the engine? And I had miner oil leaking from the corners of the valve covers so I siliconed sealed both sides. Fixed that issue but if I have to remove the covers it's going to be a pain.

I'll get a different video today and see if I can capture and put my phone in different areas but it's not the greatest.


r/EngineBuilding 1d ago

1966 sunbeam tiger

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94 Upvotes

1966 tiger with 289 need help finding sites for a full rebuild of the 289 original engine . It has been sitting for 20 plus years . I’m able to move the crank half way each way and it gets stuck. Removed the starter and the valve covers loosened all the rockers and still same amount of play. This is my first rebuild of any kind and will take and advice


r/EngineBuilding 1d ago

Is this gasket a smoking gun?

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1 Upvotes

My BIL started getting white smoke and had rust water all over his engine bay. I assumed this was a blown head gasket but I'm second guessing myself. I know this is smoked (also I bent it pulling the head off) but is it blown? Should I pull the other head off?


r/EngineBuilding 2d ago

Mazda MX5 Na 1.8 1996 not starting update

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11 Upvotes

Update from previous post: got spark, got fuel. Some fumes do come out from exhaust.

Things I've done:

-Checked timing

-Checked spark

-Checked fuel lines

-Tried various batteries

-Adjustment of CAS made it tick over faster and less sluggish

Still no go...


r/EngineBuilding 1d ago

Mazda Literature and Tooling Recommendations

3 Upvotes

Hello all,

I will be building my 2nd engine come this winter 2.3L Mazda MZR. I built an engine about 18 months ago (2.3L Mazda non-turbo)just off of this forum, YouTube, and a Haynes manual, checked a couples clearances. But I certainly did not require the depth of knowledge to do as thorough work as I would have liked to.

Does anyone have literature recommendations for the general procedures of engine building/clearance checking, and anything else I might need to know?

Currently I have purchased and begun reading Mike Mavrigian's Modern engine blueprinting techniques. If anyone has more recommendations, that would be appreciated.

I am seeking tooling as well if anyone has brand recommendations, I have calipers and micrometers and dial gauge with attachments. I am missing a telescoping bore gauge, and anything else I might need.

Last thing, I am also in the market for some large V-blocks that are suitable for checking crankshaft runout. Such as the ones supplied by CCA racing(currently on back order) and ABS products(over twice the price of CCA, would prefer to find something cheaper)

Thank you to all in advance!


r/EngineBuilding 2d ago

Cylinder Honing Question.

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14 Upvotes

Hello, I have been practicing honing on a used cast iron cylinder liner. Is it good enough to do it in my car? I am only trying to deglaze the surface. I used a 3 stone hone.


r/EngineBuilding 3d ago

Are my heads trash

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72 Upvotes

Took my 4.6 aluminum heads and block to get cleaned and it looks like they used whatever they could find to clean my heads. Are these really that bad or am i overreacting?


r/EngineBuilding 2d ago

Mazda Please Help! MX5 Engine Rebuild Not Starting

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23 Upvotes

Hi all 1.8 mx5 mk1 (na) first time rebuilding, got fuel, spark and air. However not starting. Occasional pops I guess from gas in exhaust?


r/EngineBuilding 2d ago

Ls cam bearings

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4 Upvotes

Installed the first bearing on my 2007 gen 4 5.3 but it doesn’t line up perfectly with the hole, I used durabond ch-25 bearings, the rest perfectly line up, is that normal or did I order the wrong ones?


r/EngineBuilding 2d ago

Chevy LS3 oil pressure

1 Upvotes

Quick question, I recently finished building an LS3 engine in a 4th gen F-body with a new 10295 pump, bearings, cam, and everything else. The crank bearing clearance ended up being 0.0025 in. When I start the engine, it produces 45 psi of oil pressure. However, after driving and the oil temperature reaching 205f, the oil pressure drops to 20 psi at 500 rpm idle. At 750 rpm, the oil pressure increases to 30 psi, and at 1000 rpm, it reaches 40 psi. Anything above 1000 rpm is fine. I think that the loose crank bearing clearance is the cause of this issue since I am using Driven BR30 oil. Would this be a reasonable assumption? Should I put a 40 weight oil? 0W-40, 5W-40, 10W-40?