safe compression ratio sbc

Returntrip said:

Mr. Kghost, any idea if a Bravo & Alpha drive run the same input shaft spline & size on the upper gear case? What do you think about having the balance checked on engine couplers? Thanks with any input.

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Sure I have a very good idea.
Who are you and where are you from....Seems to be some are uncomfortable with you and you may be someone else.

So if you would like me to answer either message me or maybe give the members an idea who you are.

Dieter said:

Take this for what its worth as I haven't done a SBC stroker. Most of my engine rebuild epxerince is on 65 GTO's ...and I would just stay with of the shelf full dish pistons to keep it simple...

From my understanding you want .035-.040 ish quench for a 383. this depends on the compressed head gasket thickness https://help.summitracing.com/app/answers/detail/a_id/4941/~/engine-quench

I would work with your machinist to keep it within those specs depedning on compressed head gasket thickness of the actual gasket you use, but yes typically (with compressed gaskets being .030-.040) I'd think you'd be at zero deck or damn close. If you have to do a future rebuild I woul dsuspect you can either get custom or made to order pistons or machine what ever you may need (within reason) off the top of the piston.

Hey if you do this rebuild right, that will be 10+ years down the road, Rick will be reinstated on the forum and tell you everything I just said is wrong.... hey no reason we cant still have fun here...

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When posting anything about "how to build a SBC" everyone has their opinions and experience. As many could, I could also post my opinions and experience on SBC engine builds.

I know a lot about the quench, piston profile, zero decking decisions, general engine building................It is not simple and there are so many factors to take into account before making any final decision.

But in the end, If you want it done right discuss all questions with and experienced engine builder who is operating or has operated a successful engine building business with easy to acquire references. One who dyno's his product himself!

Anything else is merely opinion..........with NO references!

Ricardo is one of those with Opinion only. Lots of them!
He thinks because he plagiarized others writings and posted somewhere on the internet (what he thinks are his WHITE PAPERS) and all over this forum, he is some kind of expert in all things SBC....................Well he is not.
He probably hasn't ever actually built one himself and if he did it most likely was over 40 years ago if not more based on much of the info he copies and pastes here.

One thing to take note on, Who else dictates opinion on that subject other than him?...............Wait for it..................


I have read virtually ever book on SBC going back to the '60's...........Does that make me an expert? No not at all. All it says is I read a lot of books.

Opinions on Materials, components, design of a build are like A $ $ holes..............everyone has one but unless they are a professional at that subject with years of real life experience their opinions are only that.

nine to one would be my vote. be sure to do an accurate cc measurement

Ok! Alriiight already! Can we just move on here? o2batsea and kghost... Returntrip is not Ricardo. Do you really think one person started a conversation as Returntrip just to give himself advice as Ricardo Marine?

Stick to engine talk. Drop all the personal bickering and off topic ranting.

Now back to our regularly scheduled program...

kghost, If I was computer savvy enough I'd send you a picture of my knuckles bleeding on this CAT 3208 engine build Im doing outside in the N.E. I dont have time for this crap. Sorry if my post sent this forum in the wrong direction, I was just trying to get help on gasoline driven marine components. Believe me ... I can figure this out all myself, but i thought it would make life a little easier to talk to people that have experience rather than spending countless hours of time researching everything. If you have a basic brain, basic math skills & some common sense this is easy, only takes time. Which is the most valuable thing to me. You can believe what you want about who i am, but my time is to valuable for this.

By the way.... James, whoever you are (Lol) Thank you.

Maybe someone can help me with this... Do they put engine oil coolers in-line on the raw water pick up for gas engines? I remember seeing P.S. coolers & fuel coolers before, but do to my lack of experience with gas engines I dont remember seeing engine oil coolers. Also, can somebody recommend a good oil pump make? Possibly what size or type on engine oil cooler.

Never had a small gas engine with oil cooler except in racing. This is a good pump if you desire high volume and higher pressure. Use in racing too. Pump drive will work with 400 crankshaft. I build 400's. Why? There's no "replacement" for "displacement".
Since 400 is a 4.125 bore, the cylinders are siamesed. Nickel content is high and core shift is closely monitored. I recommend only boring to 4.165, although some say it's safe to .060 over. The shorter connecting rods help reduce rotating weight a bit as well. Heads need to be drilled for cooling water transfer between cylinders at the top, of course, therefore 350 or 327 heads can be used. The 400 head gaskets already have the holes, you can use them as your guide, angling the drill towards the center of the head.

Thanks for the input timguy. From what I read last night higher oil volume would work but I'm not sure on the pressure end. Ive done a lot of oil passage porting work on the lifter valley returns, camshaft oil passages & main bearing supplys' on #2,3, & 4 main cap saddles, due to having 2 rod bearings on each of those areas. Its obvious now I have to increase volume but not sure about pressure. I believe the oil bypass spring in a stock oil pump is rated for just under 60 p.s.i.
I'll check out that oil pump info you sent & keep looking into the higher pressure, thank you.

Big Blocks have an oil cooler very much the same as the power steering cooler

Look here for an example

http://www.marineengine.com/parts/m...0f800700-thru-0k999999/oil-filter-and-adaptor

Small blocks do not typically have an oil cooler but if you add or have a remote oil filter mount (with all the appropriate hoses with threaded ends) you can adapt one as seen in the image in the link.



TIMGUY

Is this statement based on non marine engines? ""Never had a small gas engine with oil cooler except in racing. This is a good pump if you desire high volume and higher pressure. Use in racing too. Pump drive will work with 400 crankshaft.""

If it is you missed the entire issue with Ricardo.............Non marine -->street or race has no place here.........It may be good for you but not whats needed here.

The best oil pump to you on a NON high performance marine engine is the OEM. Over 50 years of use and as far as my experience, not one failure.

2X on the 'stock' oil pump... really no need for high volume or pressure.....unless there's been extensive machine work....and in that case, one already knows the answer...

OK, thanks for the info guys, I probably dont even need higher oil volume. The more I read it seems the oiling system on these are quite adequate. I do have a crank driven big block raw water pump "V" belt drive and 2 sets of all pulleys and accessories (Alt & P.S.) & brackets short based water pump. I was going to draw my raw water through a 11/4" seacock & strainer. Im getting rid of the Alpha drive and installing Bravo 1. I was thinking about putting a "T" or "Y" on the raw water intake to also draw water through the drive to give the upper drive case a very slight bit of cooling and put a drive shower on it if you guys agree. I was already going to put a seacock in regardless for other things, do you think i should just stick with drawing all cooling water through the drive? There is a freshly rebuilt Alpha already on the boat & I have another rebuilt Alpha in my garage. I hate to not get any use out of them but I'm afraid they will come apart with all the added torque & power from this engine. I have everything for a Bravo 1 also, except the drive itself. If i burnt out the two Alpha drives, would i have to pull the engine again to change it over to the Bravo? I repowered a boat once that had a Yamaha (believe it or not, 2 years produced) sterndrive package to Bravo 1 but there was no engine in it at that time. I would assume you guys would recomend, out with the Alpha... and yes on having to remove engine to install Bravo Intermediate housing? I was worried about using the Bravo water intake system due to things I read about the intake getting constricted. Let me know what you think. Thank you guys.

kghost thanks on the BB oil system diagram, thats exactly what i was thinking about doing. I also saw somewhere that there is a 2 quart or x-large spin on filter for that type of set up, do you think it worth digging for? How about the factory oil pan? One of the small block pans I have (Vortec engine) has a windage tray, looks well designed enough to me???

Yes, guess I stepped out of bounds slightly. Talking small blocks, yes. This pump I mentioned is good. Have experience with it. Perhaps it's overkill for marine application, but Mike has done some oil return work which, for me, is a good idea for boats used in rough seas.

Returntrip said:

OK, thanks for the info guys, I probably dont even need higher oil volume. The more I read it seems the oiling system on these are quite adequate. I do have a crank driven big block raw water pump "V" belt drive and 2 sets of all pulleys and accessories (Alt & P.S.) & brackets short based water pump. I was going to draw my raw water through a 11/4" seacock & strainer. Im getting rid of the Alpha drive and installing Bravo 1. I was thinking about putting a "T" or "Y" on the raw water intake to also draw water through the drive to give the upper drive case a very slight bit of cooling and put a drive shower on it if you guys agree. I was already going to put a seacock in regardless for other things, do you think i should just stick with drawing all cooling water through the drive? There is a freshly rebuilt Alpha already on the boat & I have another rebuilt Alpha in my garage. I hate to not get any use out of them but I'm afraid they will come apart with all the added torque & power from this engine. I have everything for a Bravo 1 also, except the drive itself. If i burnt out the two Alpha drives, would i have to pull the engine again to change it over to the Bravo? I repowered a boat once that had a Yamaha (believe it or not, 2 years produced) sterndrive package to Bravo 1 but there was no engine in it at that time. I would assume you guys would recomend, out with the Alpha... and yes on having to remove engine to install Bravo Intermediate housing? I was worried about using the Bravo water intake system due to things I read about the intake getting constricted. Let me know what you think. Thank you guys.

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How big is your boat? There are plenty of guys running 383 s in front of alphas. As long as you dont hammer it too bad and get the prop out of the water i think you will be fine. If you didnt have a drive already id say get a bravo set up, but since you have two alphas i would use them and see how it goes. Personally Im a big fan of alphas - they are light, relatively inexpensive, and basically just work.

to swap out for a bravo you need to pull the engine and swap transom assemblies as they are different between alpha and bravo.

on your other question on the oil filter chevys have two oil filters as short and a long one . The long or high performance is the one you want i think the napa part number is 1794 or wix 51794. Any autoparts store will have one...

Yes, guess I stepped out of bounds slightly. Talking small blocks, yes. This pump I mentioned is good. Have experience with it. Perhaps it's overkill for marine application, but Willie has done some oil return work which, for me, is a good idea for boats used in rough seas.

Funny, I edited my post, sorry Willie, but the old post came through. You see the time Dieter posted.....the same minute, so something strange happened, I had to change your name, don't know why I was thinking Mike??? Dah! Anyway, a key problem with higher volume pumps is that they can exhaust the sump, eh? By creating a faster drain from topside, we alleviate the problem. A larger filter adds almost 1/2 qt oil too. Not sure what pan you have but should be a 5 or 6 qt. Cars and trucks typically use a 4 qt pan. Since there is no "crossmember" or "drag link" to contend with, you can go where you want with oil reservoir.

Thanks on the Alpha info, I hate to remove it. The Alpha on the boat only has 11 hours on it & I would love to use it. I will be in the ocean and I am worried about the prop coming out of the water but will have to be careful. Any idea with your experience, when they do come apart is it usually complete failure or would you possibly be able to limp home? I know thats a tough question but 95% of my experience is with straight inboards. Im thinking running an Alpha out there, I better have marine towing insurance. Im glad I dont drink anymore, otherwise the throttle would be getting hammered a lot more, sometimes I do like to scare myself!!!

Returntrip said:

Thanks on the Alpha info, I hate to remove it. The Alpha on the boat only has 11 hours on it & I would love to use it. I will be in the ocean and I am worried about the prop coming out of the water but will have to be careful. Any idea with your experience, when they do come apart is it usually complete failure or would you possibly be able to limp home? I know thats a tough question but 95% of my experience is with straight inboards. Im thinking running an Alpha out there, I better have marine towing insurance. Im glad I dont drink anymore, otherwise the throttle would be getting hammered a lot more, sometimes I do like to scare myself!!!

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<br><br>how big the boat is and how hard you hammer it will determine how long it lives. If you want to catch air on waves it wont live long, as far how it will break and will it still work impossible to say. I never had one fail.  I think most of the failures are upper gear set or vertical driveshaft, but i think the professional mechanics here could better answer that. I just have seen that as long as  you keep up with any required seal maintenace and change the lube you should be ok. A drive shower wont hurt either. <br><br>if you search this and the Iboats forum you see enough guys running warmed over 383s in front of alphas that they are not a grenade. <br><br>you will likely have to go up in pitch with more hp. Im assuming the drive is a 1.47:1 ? <br>
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Thanks for the vote of confidence on the Alpha drive, I will have my wits about me & know how not to abuse a machine. I havent checked the gear ratio yet, I will probably also go up in pitch, also not to have such a hard bite if prop does happen to come out of the water. Todays going to be like a day off, I get to sit in a big front end loader with heat, and go push some snow around. We are expecting well over a foot of snow.

Going Bravo