Is 540 too much for a Gen VI ?
 

Got my plan, parts, & builder to go 540 on a HP500. Pulled the engine, popped the heads and and noticed the sleeves were missing!
Oh wait, let me get a magnifying glass, there are sleeves in this GenVI. Is it really safe to bore these .0030 over to 4.5"? They're paper thin stock. Anyone tried chrome or nickacil for reliability? Should I find a Gen IV block or am I just paranoid parting with my 10K? :readinghelp:

I have known lots of guys that have turned Gen VI 502's into 540's.




Darrell.

Paranoid. No problem going .030 over.

.30 over is fine in a Gen VI block theyre a pretty strong block

Umm, They don't have sleeves from the factory. Someone put them in because they one must have hurt the engine in the past. Gen VI blocks can go .60 over easy. I have a buddy running .100 over making about 700 hp right now and now problems for several years.

If there were no sleeves they would have to be nickasil, not gonna make 700 hp with rings running on castiron (not for very long anyway).

Anyone heard of a Gen VI 540 making it to 400 hours?:readinghelp: My plan is mild, just 9.3 to 1 comp & 5200 rpm, If I only get 580hp I'm still happy. Longevity is the main concern.

Nobody's iron block comes with sleeves.... Not GM, Dart, World... Nobody.

Used the wrong term "cylinder wall" thickness is my concern :drink:

The std. bore on a 502 is 4.466". Boring it to 4.500" removes .034" on the diameter, which reduces the cylinder wall thickness by .017"... a little more than the thickness of a couple sheets of notebook paper... a negligible amount. The cylinder walls are not hardened by any means to start with, so you're not removing any hardened surface either.

Most of the CI increase comes from the 4.25 stroker crank. Only a few (7 or 8) CI are gotten from borring .030 over. A lot of guys bore .060 over. I would not go more than that.

Many, many Marc 500 Bulldogs (actually 540 CI) motors have gone well past that time frame. The 540 is a great combo and isn't too extreme ( bore/stroke) at all.


Darrell.

I guess you know better.:rolleyes: I don't know what the hell you
think everyone here is running their rings on, but it is cast iron. Merc, Eikert, hell even Brigs & Stratton. Most sleeves are cast iron too.
If your only wanting 580hp you don't need a stroker either. 509ci can do it easily and reliably.

I had Lab engine (LEE) Build me a 540 tall deck.
I was talked out of a 472-488 etc.
The more you stroke the more side loading the piston does, it wants to cock in the cylinder. This is especially true because we have to move the wrist pin up and have short skirts to clear the counterweights. Piston speed is also increased.
I ended up using a Tall deck block. I would recommend that this be the way to go. Even with a 10.2" deck height anything bigger than 555 Cubes is not going to have longevity. They can be made to last longer by changing oil extremely often. 540 cubes on a 9.8" block ? If it was any good GM would have done it. Sell the 502 blocks to a teenager...
Big Block Billy

I'll let you guys know how long they last. I just got my 540's running and they make 721hp n/a. 4.250 stroke is not going to have any longevity issues.

And like what was said... if you only want 580hp... stick with the cheaper 509ci.

OK ! I have seen the uneven wear pattern in the cylinder wall. It looks like an eyebrow. This was a pair of 572's that Dean Nickerson himself jetted the carbs on. Whatever you do make sure the carb jetting is perfect. You dont want to dilute the oil this will exacerbate the problem. I can't see throwing that much money in parts into the 9.8 deck block. I feel it's like trying to make chicken salad from chicken $#!+
The 502 Blocks have alot of value. I also agree with the 509 recommendation. I think building a 540 from a 502 is like trying to sew a shirt around a button. In this case you don't even have the button ( The Block )
There's all kinds of people on here telling everyone else what they heard from someone else, most are well intended
I like most of us really can't afford it so I'm piecing my boat together and I'm in no rush to use it until I have everything even if that means next year or the year after that. Just to do it right ! BBB

"540 Bulldogs" used a Tall deck Bowtie block. Thats how I built mine..Merlin tall decks

Thanks to all:drink:
I was looking specifically for Gen VI opinions after being told that the Gen 4 block is the only way to go because GenIV way stronger than GenVI. Anyone know about the differences?
:readinghelp:

I hear your opinion on this BBB, I wish I had the extra bucks for an aftermarket tall deck.

Mercury Racing has no strength issues using them on the 525EFI, 600SCi and the 700SCi.
Innovation Marine used them for several years on the DPX600 which was a 4.250 stroke 540.
I personally built a Gen VI 548 with a 4.250 Crower crank with an M3 Procharger, R-Tech Supercooler with 7 lbs of boost, closed loop efi that ran 400+ hours and it was questioned as to why I tore it down when we looked inside. Looked perfect.

The Gen VI blocks are of better quality casting process of the old Mk-IVs (non Bowties) and fully cnc finished.

Stud the mains and heads and go make some power. (your horsepower target would not require that however)

Dave

Thanks Nordic ! Your perspective really helps, makes sense. I think the guys telling me not to stroke a Gen VI were talking about a 7.4 Gen VI not the 8.2 Thanks to all for the healthy dose of knowledge to help the paranoia:drink:

HOW DID YOU GO CLOSED LOOP?? Everyone has told me not to even try. Are you running O2s or EGTs?

I used a FAST EFI w/WBO2 system on that setup. The setup had a substantial amount of drop in the CMI tails and it seems with the ProCharger the reversion is held at bay by the constant intake pressure.
The same WBO2 sensor has been in there for 5 years and the map is setup to go 5% rich if it ever does fail. Very efficient setup!

Good luck on your build!
Dave

Yah,
540 in 9.8 block won't work, right.


2006 540 short deck still kickin a$$.



And, the only "Quality" parts used was the dart block, everything else as cheap as could be found new!

What I paid in Machine work to clearance for stroke, bore from 4.250 to 4.5 and Drill mains etc, the New Bowtie block I bought on Ebay was not such a deal and I could have had A Dart for the same money !
Nothing is better than the Dart for the money ! Blind Head bolt holes Thicker Deck surfaces, More metal all around, Better oiling, the list goes on and on. In salt water especially, it's all on borrowed time and is turning into crap.
I'd like to slow down the process, instead of speeding it up by pushing the limits of a motor and trying to do what it's not DESIGNED for. BBB

The Dart is a great piece; no doubt!
Franks goal is very mild and his 502 Gen VI block is already clearanced for 4.25 stroke, has blind holes, modern casting technolog/machining and would require little boring for what he is after. Oiling has never been a problem on a big block.
Just my thoughts for what it's worth :)
Dave