Here We Go: My 383 Stroker Winter Project

[Scott Danforth]

Re: Here We Go: My 383 Stroker Winter Project

the 1-piece/2 piece transition was '86 model year. boats may have lagged a few months depending on inventory. rollers were '88 model year for automotive, however again, boats lagged. my '88 block is a flat tappet. heck, with the implosion of the boating economy in '08, some companies are just running out of 8.1 liter engines due to inventory.

 

[John_S]

Re: Here We Go: My 383 Stroker Winter Project

the 1-piece/2 piece transition was '86 model year. boats may have lagged a few months depending on inventory. rollers were '88 model year for automotive, however again, boats lagged. my '88 block is a flat tappet. heck, with the implosion of the boating economy in '08, some companies are just running out of 8.1 liter engines due to inventory.

Thanks, I knew there was a small window between the changes. Even though the blocks were roller ready, merc didn't start installing roller cams until latter. They started with the 350 mag (1990?), and didn't get it in the 5.7L 2brl until 1997.

 

[joewithaboat]

Re: Here We Go: My 383 Stroker Winter Project

the 1-piece/2 piece transition was '86 model year. boats may have lagged a few months depending on inventory. rollers were '88 model year for automotive, however again, boats lagged. my '88 block is a flat tappet. heck, with the implosion of the boating economy in '08, some companies are just running out of 8.1 liter engines due to inventory.

I think GM stopped producing the 8.1 blocks in late 2009. I overheard two big block owners at a boat shop discussing Mercruiser using dart blocks to build there own engines. Not sure if that's true or not.

I lost track of all of the transitions... one pc to two pc main seal, roller ready, fuel pump rods, ect.
I think they even continued to make the 305 blocks two piece long after they switched to one pc on the 350. I have a 350 block with the bosses for the roller hold down but the holes are not drilled and the tops of the lifter bore are not cut.

All of this talk about changes... There was also a change in timing tab location. Your engine is running well so its probably not an issue but out of curiosity... did you ever double check yours. TDC went from like 2 o'clock to almost 12.

 

[Flysfloatsor]

Re: Here We Go: My 383 Stroker Winter Project

What I heard is that Mercury Racing kicked around using Dart blocks for some of the big boys 575-1350hp. The 525 is still based on a gm 502. Maybe Mercury Racing did use dart block for the new 1100 and 1350? Once you get into the factory blue paint, they arent messing around anymore, with quality or price...
This might be all rumor mill stuff - except for the quality and price comment, both are very high from Mercury Racing.

 

[Scott Danforth]

Re: Here We Go: My 383 Stroker Winter Project

yes, 2009 was the last year GM produced the 8.1. V-P had massive inventory and only ran out in 2011. Mercruiser switched to a derated 525 for their new 425. its a 502 (8.2 liter) from GM performance division. yes, the larger go-fast stuff is Dart based.

BTW, I designed the heat exchangers on the 1300/1350 when I was at Champ. the packaging was done by a good friend of mine at Mercury Racing. talk about stuffing 50# in a 2# box.

 

[greg82255]

Re: Here We Go: My 383 Stroker Winter Project

Yea you might be on to something with the valve cover gaskets id replace them for sure. The GM gaskets always seem to to be the best fit on those covers. The others are hit/miss.

Ive never had a one piece rear main seal leak. That was a huge improvement for gm, i wouldn't worry about that just yet. Take a good look at the front seal and at the timing cover to make sure the thrust bearing didn't wear a hole in it or something. Get a mirror and look at the rear of the manifold.

It leaked out four quarts???

Might be a pressurized leak somewhere. Did you use sealer on the threaded plugs at the rear of the block around the cam bore, and tighten them real good! Let me look at a block at the shop tomorrow and get all of the pressure port locations from a late model block. Ill get back to yea.

Warranty.... That's a good one, maybe the guy that assembled it will fix it for you! LOL

It looked like a lot of oil but it may not be 4 quarts. I'll do my best to measure it when I clean out the bilge tomorrow morning. I'll definitely replace the valve cover gaskets too. I really hope that is the problem. The threaded plugs at the rear of the block were installed by the machine shop and I'm pretty sure they did use a sealer.

I'm pulling the boat this afternoon and I'll be on it all day tomorrow. Going to be 98 degrees here - Kind of a shame I'll be out working on the boat all day and not in the water. Hopefully I can get it fixed early and salvage whats left of the day when I'm finished.

 

[greg82255]

Re: Here We Go: My 383 Stroker Winter Project

Between the fill and full line, is usually 1 qt. One qt in the bilge will look like allot. From the descriptions, I'd go with the valve cover leak. If not, and can't find it from any oil trail, Joe's method sounds like it will nail it.

I take it, your engine was between sbc transitions. A non-roller ready block, is usually a 2 pc rear main seal.

Alright, this is a little embarassing... but here goes.

I pulled the boat today, and unscrewed the drain plug to let all of the oil drain out of the bilge.. and mostly water came out. I'd guess half a quart of oil, maybe a bit more. I also found a fair amount of oil next to the stringer that holds my motor mounts, right below where the power steering hoses connect to the steering piston or whtaever that thing is called. I pulled the cap off of the power steering pump and it was empty. I had overfilled the pump a few weeks ago, and had a leak in the power steering system last year that I never found.. until now. I'm betting it's almost all power steering fluid in the bilge, and is leaking out of a hose connection. There could be a small amount of oil leaking through the valve cover gasket as well, but there's not any major oil leak.

I quoted John above because if between the fill and full line is equal to about 1 quart, then I was probably about 1 quart low according to the dipstick when I checked initially, and I thought it was way more. I figure this could be due to both the small drops that could have leaked out the valve cover, and the engine burning some oil while the rings were seating. The ring gaps were slightly larger in this engine so I expect it to burn some oil.

Time to drain all the oil out, pump in some Mobil 1 because Amsoil takes a week to ship, put on some new valve cover gaskets, check everything over thoroughly again, and do some boating. I still didn't get to play with my new Stilletto prop. I'm looking forward to that.

 

[Scott Danforth]

Re: Here We Go: My 383 Stroker Winter Project

Amsoil has dealers in your area.

http://www.amsoil.com/locator/index.aspx

congrats on finding the leak.

 

[joewithaboat]

Re: Here We Go: My 383 Stroker Winter Project

I bet that was a relief!

 

[Maddoxsdaddy]

Re: Here We Go: My 383 Stroker Winter Project

Good deal. You play with your stilleto and i'll play with my new Apollo 4 blade. Time to stop working and get out there and enjoy it!

 

[Scott Danforth]

Re: Here We Go: My 383 Stroker Winter Project

how did the new prop work out?

 

[greg82255]

Re: Here We Go: My 383 Stroker Winter Project

how did the new prop work out?

I have been so busy the last few weeks I didn't get a chance to get out to the boat until this afternoon. I was doing 59 on GPS today with 3 somewhat heavy people in the boat and nearly a full tank of gas (probably 30 gallons), and hadn't messed with the timing yet. After the problems with the oil and my low WOT RPM I set the timing back to specs from the manual. We burned through almost all the gas tubing and skiing today, so I'm going to go out by myself tomorrow afternoon and play with the timing and see how what the boat can do.

After I reset the timing last week, I managed to get the wires from the light caught in one of the belts and broke the whole thing. Now I need a new timing light, so I'll be getting one with advance. Do I need to be under a load when setting the total timing or can I do that out of gear at the dock?

I pulled the plugs last week just to take a look. The plugs next to each other in the picture are all from the same bank but the cylinders may not be in order - I don't remember exactly. They were gapped at .025" - I must have forgotten to set the gaps... Anyways, all new plugs gapped at .045" according to spec.

Seems like I might be running a little rich - What do you guys think?

Oh, in addition, I found some very fine metal shavings when I changed the oil. Nothing in chunks, just very fine shavings collected on the magnet on the pan screw. I've been doing some research and found that this is normal for the first oil change. I assume that's ok as long as they don't keep coming back?

 

[Scott Danforth]

Re: Here We Go: My 383 Stroker Winter Project

your just a bit rich on five of the plugs, three look good

your advance is RPM dependent, not load dependent. you can set the RPM and check total advance sitting at the dock.

btdt with the timing light leads a few times. :facepalm: depending on the brand, you can buy new leads.

 

[joewithaboat]

Re: Here We Go: My 383 Stroker Winter Project

Fine metal is not uncommon for the first oil change

Like Scott said, three of those plugs look good. At least from that picture. By the way if you are looking at something on paper on how to read plugs for fine tuning be careful. They are referring to engines run on race gas. It is very difficult to fine tune running the junk pump gas we have these days. General observations are still ok and helpful.

I have also done that with the timing light as well as burning them on the headers. I have a few remnants of wires, clips, leads in the bottom drawer of my tool box. LOL The last time i fixed mine with a 5 dollar pawn shop light. I couldn't find the tool truck fast enough....

How is the RPM doing with that prop at WOT?

 

[greg82255]

Re: Here We Go: My 383 Stroker Winter Project

Fine metal is not uncommon for the first oil change

Like Scott said, three of those plugs look good. At least from that picture. By the way if you are looking at something on paper on how to read plugs for fine tuning be careful. They are referring to engines run on race gas. It is very difficult to fine tune running the junk pump gas we have these days. General observations are still ok and helpful.

I have also done that with the timing light as well as burning them on the headers. I have a few remnants of wires, clips, leads in the bottom drawer of my tool box. LOL The last time i fixed mine with a 5 dollar pawn shop light. I couldn't find the tool truck fast enough....

How is the RPM doing with that prop at WOT?

So if 3 plugs are good and 5 are rich, should I just leave it alone? I don't want to create a lean condition in any of the cylinders. I've run only 93 octane pump gas in this engine.

I don't remember exactly but I think I am running around 4600 rpm. I'm going to go out to the boat tomorrow and play with the timing and see how much more I can get. I am guessing that 4600 is a little low. I am also debating buying one of those holley proform carbs that Joe suggested.

 

[John_S]

Re: Here We Go: My 383 Stroker Winter Project

So if 3 plugs are good and 5 are rich, should I just leave it alone? I don't want to create a lean condition in any of the cylinders. I've run only 93 octane pump gas in this engine.

I don't remember exactly but I think I am running around 4600 rpm. I'm going to go out to the boat tomorrow and play with the timing and see how much more I can get. I am guessing that 4600 is a little low. I am also debating buying one of those holley proform carbs that Joe suggested.

Using a slip calculator, indicates about 10% slip which is reasonable for your style boat. (assuming 23" pitch prop)

4600 is low, and would seem that your engine should be able to spin that prop better. But, if timing checks out, might want to drop back to 21" pitch. Your top speed won't change much, but your accel in any rpm range will be much better.

You are not using all of that 750cfm carb currently. Can't see that a proform is going make much noticeable improvement.

 

[joewithaboat]

Re: Here We Go: My 383 Stroker Winter Project

I dont pretend to have a ton of experience with tuning high performance engines on the water, as i have said in the past most all of my experience has come from race cars. I have wrenched a lot on in/out boats, but mostly stock/near stock.

A couple of observations...
Make sure you keep running the 93, especially if you are tweaking the timing.

That engine should be turning more RPM, so either the prop is too big or something is up with the tune up. For now, I suspect it is the prop.

I would be more comfortable with a prop that would reach the peak rpm of the cam.
An engine that can over rev is working less than an engine struggling to reach max RPM.
That cam is going to make peak HP on the other side of 5,000 RPM

John is correct about the fancy carb not making much of an overall improvement as far as seeing big gains in MPH or anything. Its not going to change the condition you have now of the engine not operating at peak HP range.

However if you are accustomed to the fully adjustable features of a prepped Holley it would make you throw stones at everything else.

If you did buy one i would get it from a custom carb shop, like Pro Systems, so it will come tuned close when you get it. Folks that dont have one always talk about them being too expensive... The same ones who bought more than one $450.00 (+) props before they found the one they liked....

 

[Scott Danforth]

Re: Here We Go: My 383 Stroker Winter Project

I would say your right on the bubble with your Air/Fuel ratio. I would tweek it just a bit up, and watch performance, then back down just a bit.

4600 RPM is low and that could be a couple of things - timing is off, A/F is a bit off, spark scatter from the distributor, cruddy fuel, you have hit the hp limit of the engine/hull, your tach is off, you left the anchor line out and are plowing a new trench

you will find the problem. with 93 octane, you can run a bit more ignition timing. Where is your base timing now?

 

[joewithaboat]

Re: Here We Go: My 383 Stroker Winter Project

I wouldn't get too caught up reading plugs. They are a good indicator of overall running condition or health of the engine but... If you were trying to judge the main jet size by reading the plugs you would need to run at WOT and shut the engine down as quickly as possible not letting it idle too much. You could for example have a perfect or slightly lean WOT condition, if you had a pig rich or poorly tuned idle circuit you could throw off the plug reading while idling back to the dock. Then mistakenly go down a jet size because the plugs look rich. Or vise verse....

Be patient, follow the instructions that came with the carb for tuning. If you haven't done so already take someone to manage the helm with you and check to see that at WOT on the boat, the carb is actually running at WOT.

 

[John_S]

Re: Here We Go: My 383 Stroker Winter Project

After timing, I'd be checking to see how far the carb air valve is openning under wot. It can be a bit "fun" but a 2nd person can slightly open the air valve from its wot position (engine and flame arrestor off). If you gain more speed you have found an issue. You have to be careful though, it can cause a severe bog if it is opened too far or too fast. At 60mph, that might send your head toward the windshield frame.

PS: Agree with Joe on the plugs.