safe compression ratio sbc

[Returntrip]

Good morning, I havent had time to be on the Forum lately,
Rick, I have been on the phone with 9 different machine shops in the last 2 weeks, 7 of them specializing in marine engines. Im trying to figure which way to go with this engine build (especially piston profile).
I have explained to them in detail the varied information I have gotten about piston profile vs. comb.chamber profile, location of peak cylinder pressure, cam dynamics & and quality and types of rotating assembly components.
7 out of 9 totally are for the LCQ style build (one of them automotive machine) 1 said either way would work O.K. (whats O.K.?) and 1 shop said he has used flat tops or relieved cut pistons because thats what he has seen when disassembling marine engines.
After much research and consideration I will be going with your suggestion with the piston design you have laid out in detail to hopefully build a durable, efficient engine with very good torque. I have also opted out of the Bowtie Vortec heads & went with the AFR 195 cylinder heads, whth added inconnel exhaust valves installed. These heads have a 77% flow rate which is much higher than most and will give me a better choice on setting up the correct cam profile i want. Here is a list of some of the parts I will be using if it helps anyone at all. (Noting 1st. of all, this is not a low budget build.

(1) Mahle phosphorus coated forged pistons. (9.1) comp. Explanation, hypereutectic pistons would have been strong enough, BUT... if one fails, a hypereutectic piston will shatter like glass and surely lead to catastrophic engine failure. Whereas a forged piston will most likely stay together.
(2) Scat pro comp forged 7/16 connecting rods. (already are designed with clearance in mind for stroker application.)
(3) Forged internally balanced cross drilled crankshaft. (Lighter weight for rotating mass)
(4) High volume oil pump ( not high pressure)
(5) Roller camshaft, & valvetrain (specs to be determined) cyl. head flow #s and lift specs. will dictate final camshaft selection.
(6) Closed cooling system (extremely important for longevity, especially with any aluminum components)
(7) Many hours of oil clearance and porting work to improve & re-direct oil flow, even on pump main cap and pump. Always check, even new pump rotors were slightly out of spec. like mine. Must do serious reading on pump mods to be done correctly.
(8) Time, patience & cleanliness.
(9) Listen to everyones suggestions, and research.
I truly appreciate everybodys input. I am fortunate I dont have a strict budget to stick with. I have been laying on my back and been on my knees (Dont take that the wrong way) in the engine room, bilge or deck of boats for decades (mostly diesel), Im in my late 50's and do not particularly care to do a job more than once. I know there is a multitude of things I didnt mention or list. I am also sure there may be people that dont agree with some or any of my decisions. Upon completion of this build I will provide a detailed list of components used, and this spring and throughout the summer will give updates on performance of this build.
Im sure i will have many more questions along the way, building the engine is only one component of safe, reliable, enjoyable boating. I not only enjoy boating but I use mine for transportation. Im sure we are all on this forum because at one time or another, we had an allure to the water, a passion for boating and working with our hands.
I want to thank everybody so far, especially Rick for all your input. I look forward to hearing from people with comments & suggestions. Thanks, Johnny V.

[RicardoMarine]

......

Good morning, I havent had time to be on the Forum lately,
Rick, I have been on the phone with 9 different machine shops in the last 2 weeks, 7 of them specializing in marine engines. Im trying to figure which way to go with this engine build (especially piston profile).
In my opinion, with the Vortec heads, your best bet will be the LCQ style profile that will better "mirror" the cylinder head's quench surface.

I have explained to them in detail the varied information I have gotten about piston profile vs. comb.chamber profile,
You'll have no choice but to consider the SBC's wedge shaped combustion chamber.
The important aspect will be the shape of the cylinder head's quench surface.

location of peak cylinder pressure, cam dynamics & and quality and types of rotating assembly components.
7 out of 9 totally are for the LCQ style build (one of them automotive machine)
Some would say that those 7 guys are the guys who can look into the headlights without being mesmerized.
I'm glad that you found them!

1 said either way would work O.K. (whats O.K.?)
Some would say that he's the guy with less experience, and who will be mesmerized by the headlights.

and 1 shop said he has used flat tops or relieved cut pistons because thats what he has seen when disassembling marine engines.
Some may say: "Follow the heard...... they will lead you to the slaughter house."

After much research and consideration I will be going with your suggestion with the piston design you have laid out in detail to hopefully build a durable, efficient engine with very good torque.
Just to be clear...... a 12* to 14* LPCP is what makes greater torque.
We can't get there with the GM Full Dished profile.

I have also opted out of the Bowtie Vortec heads & went with the AFR 195 cylinder heads, whth added inconnel exhaust valves installed. These heads have a 77% flow rate which is much higher than most and will give me a better choice on setting up the correct cam profile i want. Here is a list of some of the parts I will be using if it helps anyone at all. Noting 1st. of all, this is not a low budget build.
I think that your more relaxed budget is important to understand for those who are posting to your thread.

(1) Mahle phosphorus coated forged pistons. (9.1) comp. FYI...... you can go up a point or two from that with a good quench dimension!
Explanation, hypereutectic pistons would have been strong enough, BUT... if one fails, a hypereutectic piston will shatter like glass and surely lead to catastrophic engine failure. Whereas a forged piston will most likely stay together.
(2) Scat pro comp forged 7/16 connecting rods. (already are designed with clearance in mind for stroker application.)
(3) Forged internally balanced cross drilled crankshaft. (Lighter weight for rotating mass)
(4) High volume oil pump ( not high pressure)
(5) Roller camshaft, & valvetrain (specs to be determined) cyl. head flow #s and lift specs. will dictate final camshaft selection.
Yep.... let your camshaft company Tech/Representative help you with this.

(6) Closed cooling system (extremely important for longevity, especially with any aluminum components)
Yes!
(7) Many hours of oil clearance and porting work to improve & re-direct oil flow, even on pump main cap and pump. Always check, even new pump rotors were slightly out of spec. like mine. Must do serious reading on pump mods to be done correctly.
SBC enthusiast Bill Jenkins pioneered this idea in the 60s.
Good call!

(8) Time, patience & cleanliness.
Absolutely!

(9) Listen to everyones suggestions, and research.
I may disagree with you on the first part of that one!
As for research..... I agree.

I truly appreciate everybodys input. I am fortunate I dont have a strict budget to stick with. I have been laying on my back and been on my knees (Dont take that the wrong way) in the engine room, bilge or deck of boats for decades (mostly diesel), Im in my late 50's and do not particularly care to do a job more than once.
Old saying: "if you're not willing to do it right in the first place..... when will you find the time to do it again?"

I know there is a multitude of things I didn't mention or list. I am also sure there may be people that dont agree with some or any of my decisions.
IMO, you are making some good decisions.

Upon completion of this build I will provide a detailed list of components used, and this spring and throughout the summer will give updates on performance of this build.
Im sure i will have many more questions along the way, building the engine is only one component of safe, reliable, enjoyable boating. I not only enjoy boating but I use mine for transportation. Im sure we are all on this forum because at one time or another, we had an allure to the water, a passion for boating and working with our hands.
I want to thank everybody so far, especially Rick for all your input.
You are very welcome.

I look forward to hearing from people with comments & suggestions.
Thanks, Johnny V.

[timguy]

Rick (9).....Listen is okay, but following may be another story.....

[Docksidemarineservices]

Rick (9).....Listen is okay, but following may be another story.....

Rick has been banned.

[Returntrip]

Hello Timguy, I just sent you a private message, your messages are full

[timguy]

Okay I'll clean some out....thanks. What are the grounds for getting banned? What does it mean?

[kghost]

What are the grounds for getting banned? What does it mean?

Stick to the original post/question.
Do not continue to HIJACK every post you chime in on.
Stop thinking your opinion or supposed "expertise" is the end all be all.
Stop inserting the same opinion over and over and over and over and over and over again in any post that has the letters SBC.

Heed the actions that occurred and keep the post, questions and answers on target.

No one really cares about your 50 years of engine building 50 years ago. ""SBC enthusiast Bill Jenkins pioneered this idea in the 60s.""

Many here have equal experience but this is NOT and engine building forum. It is Exclusively Mercruiser and is for the REPAIR of Mercruiser problems, Again Not how to build a small block chevy.
Hey its great to do so but to ask anyone here who's expertise is in repair NOT engine design/building is OFF TOPIC for any topic.

There is a separate forum page for just engine related subjects/questions

Keep your responses Marine safe and do not suggest back yard repairs on many topics that could endanger the Original Post/person. Most dont know a lot and that has to be taken into consideration.

And lastly, DO NOT USE ACRONYMS..........spell out your words and DON'T BE A RICARDO

[Returntrip]

You would think the usual behavior that would get anybody banned, I guess....When banned I guess you cant post or reply. Ive never been a forum guy. I didnt witness anything that would justify that. Let me know when your message box is purged.

[Returntrip]

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.

[Returntrip]

Im guilty of posting about so much engine building. 1st. time ever on a forum & relly bad with computers. I just clicked on one day & never bothered to even see I was posting on a sterndrive forum.

[timguy]

So here's a guy with 12.4 thousand posts? Banned? I'm gonna start to cry. His time devoted to this forum has burned up almost a full half year of his life? So what if he doesn't like dished pistons.....?

[Returntrip]

I dont get it

[Docksidemarineservices]

Stick to the original post/question.
Do not continue to HIJACK every post you chime in on.
Stop thinking your opinion or supposed "expertise" is the end all be all.
Stop inserting the same opinion over and over and over and over and over and over again in any post that has the letters SBC.

Heed the actions that occurred and keep the post, questions and answers on target.

No one really cares about your 50 years of engine building 50 years ago. ""SBC enthusiast Bill Jenkins pioneered this idea in the 60s.""

Many here have equal experience but this is NOT and engine building forum. It is Exclusively Mercruiser and is for the REPAIR of Mercruiser problems, Again Not how to build a small block chevy.
Hey its great to do so but to ask anyone here who's expertise is in repair NOT engine design/building is OFF TOPIC for any topic.

There is a separate forum page for just engine related subjects/questions

Keep your responses Marine safe and do not suggest back yard repairs on many topics that could endanger the Original Post/person. Most dont know a lot and that has to be taken into consideration.

And lastly, DO NOT USE ACRONYMS..........spell out your words and DON'T BE A RICARDO

This should help you get it.

[Returntrip]

Relax

[mcomm]

Don't do it

[Dieter]

I dont get it

If you look at other similar posts Rick had a habit of arguing with everyone , especially this long tirade on piston profile we have all seen a hundred times...Jim who runs this site and marine engine had previously crowned Rick as not only the poster who had been complained about the most but also the one who had complained about the most other posters...

bottom line ...back to your original question as I saw your post on I boats forum regarding con rod length. You got a couple of legit posters to respond there and you have a couple of good ones here - what else do you need advice on?

[Docksidemarineservices]

Don't do it

Ha ha.....

[timguy]

So here is where we move to discuss, in detail, engine rebuilding. Eh? Returntrip, you should have posted here. Trouble is......this gets very few views. For instance right now there is 1 person on it versus 25 for the Mercruiser Sterndrive.

[o2batsea]

Returntrip and Rick are the same person.

[kghost]

So here is where we move to discuss, in detail, engine rebuilding. Eh? Returntrip, you should have posted here. Trouble is......this gets very few views. For instance right now there is 1 person on it versus 25 for the Mercruiser Sterndrive.

You hit the nail on the head. It was all about the views/Post counts. Virtually ever thread the same info was injected unrelated to the original post question/issue simply to increase post count

[timguy]

o2, I don't think so. Return trip is a heavy marine diesel mechanic. He has messaged me.

[Returntrip]

Wow, this is getting crazy. I just wanted to learn....

[o2batsea]

I'm sure Rick will answer your email.

[timguy]

He cannot communicate through messaging here, I have no contact with him, maybe Returntrip does. Guess I'll have to be careful.....or the axe will drop on me too!

[o2batsea]

wasn't talking to you post count tim

[Returntrip]

Thanks Dieter , I had no idea about what went on in the past on this forum. Im starting to look at old posts and see it now. I do have a question, Do you recommend zero decking the block or should i leave the pistons down in the jug slightly and use a thinner head gasket? What if i neede to deck block in the future if its zero decked already? and what type composition head gasket material is good for gas marine engines?

[Returntrip]

Who cares about post count!!!! Is there a pot of golden pistons at the end of the forum rainbow???? I have no idea about a person or people posting the same info over & over again. Im new to this forum thing, Im probably not even replying to posts correctly. I just go under the last posted thread & hit post quick reply instead of a general post. I am too busy doing a CAT engine right now an dont have a much time for the forum

o2batsea... I am WILLIAM WALLACE..... not Rick Ricardo

[timguy]

Returntrip. Regarding post number 43 here is what you can do. We often did this at the machine Shop to increase the compression slightly on the pure stocks which used a 305 Chevy. We would offset while grinding the crankshaft to gain stroke. This would be a way to continue to use a block that has been decked except of course you would reduce stroke and the rod journals can be turned up to 20 safely. The 305 cranks are slightly different than the 350s and we found out that often the counterweights have larger and deeper bores in them.
But most certainly any 350 crank can be used in a 305 as long as it is balanced.
Old expression: There are only two kind of racers....... there are "cheaters" and there are "losers".

[o2batsea]

o2batsea... I am WILLIAM WALLACE..... not Rick Ricardo

Your pic is all over the web

[Dieter]

Thanks Dieter , I had no idea about what went on in the past on this forum. Im starting to look at old posts and see it now. I do have a question, Do you recommend zero decking the block or should i leave the pistons down in the jug slightly and use a thinner head gasket? What if i neede to deck block in the future if its zero decked already? and what type composition head gasket material is good for gas marine engines?

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/an.../engine-quench

I would work with your machinst 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...