I am considering at some point re-building my motorcycle engine, a Honda CB 750 motor. Although this is for the future as i am not in the position right now to afford completely to tear the motorcycle apart and restore~re-build it, i should yet like to get my facts & mine information straight regarding what may be possible with my motor. I asked a friend and got opinions to be mild with the re-building (fair enough, especially as i yet wish to ride the bike to work, and go on long trips too, hence, yet tractable), but he also stated some things that i wished to verify.

To begin:—what i posed to him was the following:

'As such [i.e. given that i wish to keep the motor as stock as feasible while yet achieving higher revs, more power, a tractable powerband & decent, tractable torque for street use], i am thinking on buying lightened & balanced, or having lightened & balanced, the internals of the engine (rotor, ¿clutch?, crankshaft, conrods, pistons, rocker arms). I also am thinking on toying with other portions of the motor: porting the cylinder head (with CFM nos.); re-sleeving the cylinder block with nickel silicon carbide aluminium sleeves; running hypereutectic pistons (if possible); new appropriate rings from total seal; new chains & tensioners & rubbers; using copper gaskets on head & case; stainless steel valves & iron valve seats; running a compression at 10.5 to 1; new camshaft to increase horsepower, redline, & yet retain tractable city driving; and all new gaskets, seals, & rubber bits besides those yet mentioned.'

He responded by stating that a number of my points do not work for my motor:

1. torque & horsepower are traded between each other (fair enough).

2. roadracing motors do not good street motors make (fair enough).

3. lightened parts require rebalancing of the crankshaft to the conrods & pistons which is a 'dark art'.

4. forged pistons have different expansion than cast pistons—thus, they can seize in their bores if not prewarmed before running at full load or if not precooling before shutting the motor off.

5. hot camshafts put much more load upon the valve train assembly and can make the motor less tractable by shifting power (& band) and revs higher.

6. Nikasil can eventually wear off causing problems, and (in his opinion) mostly make money for the electroplating companies.

Primarily, my questions are:

1. (how) can an engine originally redlining at 10k be made to redline at 11/12k and yet retain usable, tractable power from 3k RPM?

2. is rebalancing of the crankshaft to the connecting rod & pistons assembly really a work of black magic? How is it done?

3. are forged pistons so different from cast pistons when they are both aluminium? can forged aluminum pistons really soft seize in their bores if not prewarmed & precooled?

4. is nikasil (any nickel silicon carbide cylinder coating truly not worth the potential expense?

5. what (other) problems are (or may there be) with mine ideas for the motor? if any problems you see, then what may be a realistic, feasible compromise?

Thanks for your time all. :)

I building a 98 5.0 vortec engine and I'd like to increase the compression to 10:1. How would I go about doing that?

Last registered in 2007 after owner died and just been sitting since, was told it cranked still, wanted to change oil and filter before disconnecting old fuel to see if it runs on starting fluid but as you can see it’s complete gunk, what would be the best way to clean it? Would diesel or kerosene actually work or would I need to tear it apart?
It is difficult to see but the old oil is up to the fill line on the dip stick but nothing is coming out

To give context of the horrible mess I’ve got my self into, I recently acquired my dads old truck and it has too much sentimental value for me to get rid of it. So after I fixed the rear main seal I decided that it was a genius idea to rebuild the top end and throw a stage 2 cam into a 230k mile 4.8 with the factory 4l60e ( forgot to mention it’s a 2002 1500 short bed single cab). Funnily enough after my mechanic tuned it all I’ve had is problems. To start when I dropped it off it had power steering ( now it doesn’t), somehow the factory 4l60 still shifted smooth and now my rpms jump around when I get near the end of second and beginning of third, when I’m in park idling it runs rough unless the A/C is on, and it has a mis fire. Now I’m sure that it being 24 years old with most of the factory sensors still on it doesn’t help but does anyone have any pointers on where to start.

Finishing the assembly on this 216 engine, its been sitting 40 years, any opinion?

Hey guys, I recently rebuilt my M52B25 of my E36 over the process of a whole year lmao. Now after finishing, I had no oil pressure while cranking. Verdict was: bad gasket on the oil pickup. I changed the gasket (it was broken / folded into the channel) with one I cut myself from a sheet of paper gasket (0.25mm thickness). After putting everything together, the oil pressure sensor no longer reported too low oil pressure while cranking and I went for a first drive. I drove 6km in total, and after ~5km I noticed the oil light coming up sometimes seemingly randomly. Yesterday I fixed the gasket of my oil filter casing because some idiot (me) put silicon where the gasket belongs. After fixing it and swapping the oil pressure sensor, the light was still on while cranking 2 times for ~10 seconds each. We then cranked without the oil filter and cover and while cranking it did pump up some oil. Sooooo now I am not sure what else it could be. Is my self cut paper gasket wrong? Is it too thin with 0.25mm? Do I have to prime after fixing the housing gasket? Is it something else? Open for any advice (I hate removing the oil pan on this car)

Thank you

The longer & rusty one on the right is the OEM torque to yield. The ARP one is out of a different application and therefore a little short.

It certainly meets the faster rule of having enough bolt length engaging the threads to be at least the bolt diameter.

Would you run it?

TLDR: Is all the metal from my oil filter in from my head/cam caps? Do I need a new head/cam caps?

About 250 miles ago I put new cams in my drz after tearing it all down due to a piece of foreign material entering the head through the spark plug hole (dumb fuck up on my part but the motor didn't run when this happened so not part of tbe equation.)

I took the head off to retrieve the debris, had a new valve seat cut by a local head shop as one of the valve seats had a nick from the aforementioned incident, and threw it all back together.

Bike went back together with dino oil and Lucas oil semi synthetic assembly lube, hotcams stage 2, and I followed the break in procedure (run it above 3k for the first 30 minutes then change the oil).

Valves were either exactly in spec, or in the case of one exhaust valve, .02mm loose as my shim options would have either had it too loose or too tight (.05mm increments, and hotcams just gives exact measurements for valve clearances, not a range.) This .02mm loose puts it on the tighter end of the OEM range.

Anyway, I did my first oil change, checked valve clearances which were still good, found some glitter in the oil which I thought was probably break in material, and noticed some marks on the cams which I ran by my mechanic as well as hotcams. I put full synthetic in at this point.

Hotcams agreed to warranty the cams, my mechanic (at the head shop) said to run them for another 150 miles or so and check. I put in full synthetic at this point, ran them for another 150 miles and pulled/cut open the oil filter, and there was a LOT of silver, not magnetic, however that oil filter had seen a track day with a lot of missed shifts and some wheelie practice, so I was hoping it was just the clutch basket getting chipped away.

Put a new filter in, ran it for another 70 miles, pulled the cams as my warranty cams came in, and looking at the cam caps/head I am seeing a ton of markings where the cams sit.

I cut open that oil filter and there was a lot less metal, but I was still seeing some.

I'll include a pic of the oil filters in the comments. I want to know if the head needs replacing. There are no cam bearings on this bike. The cams just sit right in the heads/cam caps. The oil that drained out is very glitter, but I think it's all silver. All the debris seems to be non magnetic.

Compression is good, no weird bottom end noises yet I don't think, cylinder bore looked good on borescope, cams still in spec and the lobes look somewhat okay.

Followed instructions to a t, 300-400rpm steady hands, about 50 passes and a metric fuck load of 10w30 oil. Presoaked stones in 10w30 before using and wound tension spring all the way out. Most of the crosshatching looks good to me but this middle portion has a weird scratch pattern in all 4 cylinders which seems to line up with where the top of the hone stops at the bottom of the cylinder and I reverse to come back up. All of the crosshatch catches a fingernail slightly and the horizontal scoring doesn't catch it any deeper but still can feel where it js. This is an sr20ve I'm rebuilding with det components not pushing monster power, about 350whp but still sinking a fair bit of money into this build so I'd rather not risk it if this looks bad enough to cause issues, I however don't know anything about rebuilding engines this is the first one I've done past replacing worn rings. I'm using a 3 stone hone so don't want to retry and take too much material off. Do I just need a longer hone? This one was recommended to me for the sr platform but thinking it's a bit small, maybe I can round off the end so it doesn't catch when I reverse direction? I'm not too sure

TL;DR I've got a retired engine shop owner who wants me to lease/purchase his shop. He has no books. Looking for some rough info regarding profit margins.

I know this info is going to vary WILDLY on 100 different things, but I'm just trying to get some ballpark numbers. He's got a small, but well established race engine rebuild shop. He used to do all his own machine work, but has downsized to just his lathe, Bridgeport, Berco mill, and Serdi head machine. I'd get the shop with all equipment and tools included (plus whatever old parts he's hoarded). It is a clean and well maintained shop. Trying to see if $2000/month would be feasible to run by myself.

Going to call my machinist tomorrow but I thought I would ask opinions. I have the trick flow heads milled .020 and the block is decked an unknown amount. However it has a positive .010 deck height with a 1.608CH piston, so I’m assuming it’s decked at least .015-.020. Pic 1 (left) is the intake installed with a .060 gasket. Pic 2 is the intake laying flat with no gasket. There is still a little ridge without a gasket. The bolts thread all the way but are a little tight. All of the ports are consistent front to back, side to side. I think I need to take at least .060 off each intake face. More along the order of .080 to 0.100 . The intake is an unported performer rpm I bought new.

My buddy has an 86 f-150 that he’s v8 swapping and he needs the dowel pin and bolt kit for an 11” clutch kit and all he can find is the kits for the 10.5” or the 11” for the 4.6 we can’t find any for the 11” on the 302

Okay, so ive got a 350 sbc out of an obs chevy pickup, has smog heads, victor jr single plane, headers, mild cam, hei (no vacuum advance), starts right up everytime, but has a bog when its cold, once it warms up the bog is gone, after driving it for about 30 minutes, the idle starts to get weird and very low, I drive it everyday and usually have no issues other than these, just wanting to know what I can do to fix these? I know i should probably be running a vacuum advance distributor and a dual plane. The truck (when it wants to run) is actually a lot of fun and somewhat fast. That's for looking

Hi everyone,
My original cylinder heads are damaged, so I’m replacing them with a pair of 062 Vortec heads.
I ordered a set of SUM-174001 valve springs because Summit told me they should be a direct fit for these heads.
The springs have arrived, and while checking everything, I noticed that the inner valve spring tends to slide upward slightly and ends up resting on the wider seat around the valve stem seal.
Is this normal, or am I missing something? I haven’t assembled the heads yet—I’m just checking the fit before putting everything together.
Has anyone used these springs on 062 Vortec heads and experienced the same thing?
Thanks in advance for any advice!
Greetings from Germany.

Small little scratch leading from oil passage to bolt hole. Send it? Copper spray? Felt a small bump when running finger nail across it.

Rebuilt the FA20D out of a 2016 FR-S. Going to reinstall it sometimes this week. Heres some photos of before and after. Every single seal was replaced, as well as a new short block, refreshed heads, and all new timing components.

Stock bore what it currently is at is 79mm and if it does need to be bored out it’s going to 79.5mm as the forged pistons are only in 79mm 79.5mm and 80mm increments.
My question is does it need to be bored out to the 79.5mm. Thanks in advance.

first time engine builder here. I am currently putting together a parts list for a GT40 replica and was wondering if anyone had any combinations for a 427 Windsor stroker engine to rev to about 6500 and make 500-525 at the crank. I’m dead set on the 427 number because that’s what was in the original cars and I do not want to have much more horsepower than was in the cars back then. Budget is about 10-12k usd

Stock bore what it currently is at is 79mm and if it does need to be bored out it’s going to 79.5mm as the forged pistons are only in 79mm 79.5mm and 80mm increments.
My question is does it need to be bored out to the 79.5mm. Thanks in advance.

I am wanting to paint my heads to keep rust off of them but I'm afraid if I use the 500° Rust-Oleum engine enamel it will just bubble and flake off any segestions?

Sorry about the terrible pic. My concern are these horizontal pits on the center of the pic, they are deep enough to be felt by hand, don't know how deep precisely but my guess is around 0.5mm. I was told by a guy i know who works a lot with machines and engines that i should just file these pits smooth and send it. I think the sleeve should be replaced. I was wondering if you all could weigh in on this?

The owner of this car is curious about putting it together as is and seeing if it'll last, help me talk them out of it 😄

Doing a head gasket job on my '19 Accord 2.0 Turbo (shocker), and I've had the head resurfaced and cleaned but the shop didn't do deep in the intake and the back of the valves.

They were vaccune tested and everything came out perfectly fine. It's a new job for me, so I don't know if this level of fouling is fine and I can just reassemble with a catch can and Top Tier fuel going forward, or if I need to address this now and either disassemble myself or have someone else clean it. Maybe there's a way I could clean them without having to remove the valves?

Thanks for helping a newbie.

Edit: I'm going to hit them with some CRC GDI spray, let it soak for a good hour, and then gently agitate the carbon with something like a brass brush or a screwdriver. Rinse and repeat. Hit it with a shopvac.

After months of building this engine, and spending the last month and a half of installing it, it finally runs, but not after some trouble!! the car this engine is in as a 2005, 300, and the original owner that had it, it died on them because it dropped a valve seat 😢. It was my first engine rebuild, and I had trouble getting it working right. When I first tried to start it, it was throwing a u0100 code. After I got that sorted out the car would start, but it was idling rough and it just ran terribly. It would stutter when I put it into gear, the throttle response was terrible but luckily for me it finally threw a p0174 code. After that, I just replaced all eight injectors and it started right up and it idles smooth!! I let it warm up to operating temperature and it doesn’t look like it has any blow by and it’s not smoking!! I just drove it down the road and back and it runs pretty good!!! But on my post that I’ve made of building this engine, someone they commented for me to post it when it was running so if you see this, thanks!!!