articfriends

Finally started on freshening my 540 blower motor,110 hours/2 seasons,je pistons w/total seal rings,ceramic coated tops/coated skirts by swain tech. Motor has been sitting around my shop since fall when I r/r'd it to sell ext box but haven't had 1 spare minute (working 96 hours a week plus doing a few trans missions/rearends for customers). Anyways charged up a cranking battery,rigged up a starter trigger and did a compression test. Had 155-159psi on all the cylinders,originally off the dyno motor cranked almost exactly 155psi on every cylinder (carbon probably raised it slightly). So far so good,did a leak down test,1,2,3,4,5,7 were all between 4 to 6 % (they were 4-5% after rings seated off the dyno 2 years ago),unbelievable,I was almost starting to think I might leave short block assembled and just freshen the top end as I started on the idd side and worked my way down the even side towards the back. Got to #6 (which cranked 156,ever so slightly less than the others)-14% leakdown ,stuck my ear over the valve cover breather tubes,you can definately hear it in the crankcase. Did #8,20%,placed my hand over exhaust port (motor is sitting on my bench) and you could feel the air coming out the port slightly. Pulled the valve cover and tapped the valve stem w/brass hammer a few times in case there was some carbon or rust holding it open,leakdown dropped to 14%,this was the cylinder that cranked 155 psi. So much for dreamy thoughts of just doing the top end!. The numbers are still pretty good BUT the other cylinders are sealing VERY well compared to #6 and #8,I will be tearing into it further in next few days. We will see if the blower lunching last year chewed up these cylinders slightly or if for some strange reason they ran a little leaner than the others,I will post pics for you guys interested too as always,Smitty

articfriends

Alot of my 540 parts (crank,rods and block) are 4 seasons old and have about 240 hours on them. I plan on sending my ati balancer in to be rebuilt,new lifters,valve springs,gaskets,rings,bearings,timing chain. Some parts I'm not sure what to do with like the rods and crank. During the last rebuild they still looked like brand new,a very lite polish cleaned up crank but it had 130 hours at 750 hp max then,now it has another 110 hours and has seen 6000 rpms at 950 hp. Should I just replace the rod bolts/have every thing checked for cracks and do another lite polish if stuff looks like new (motor has ran flawless with no oil pressure issues) or sell stuff dirt cheap and replace with brand new so it doesn't blow up in next 120 hours? These parts don't last forever but are they really exspendble at these power levels? I'm not a millionaire like some osoe'rs with a unlimited ceheck book but it would be false economy to save 2000$ on these parts just to lose the whole motor later. Any opinions? 4340 american made hrc crank permatoughed .080 deep and billet hrc rods rated to 1000 hp, Smitty

bobl

You have to evaluate how you run the boat(compared to a racing environment). The life of these parts is more related to cycles than time. So, an engine that averages 3500 RPM over it's life will certainly last much longer than one that has an average of 5000+ RPM. Even though you make 950HP, what percentage of total use do you utilize it? My guess is your rotating assembly will last for a long time. Freshen the rings & bearings and go for it.

Actually I'm doing the exact same thing to my engine. It had over 500 hours on it. One cyliinder was leaking bad. Turned out to be a score. I honed it .005 and had a custom set of pistons made. It's going back together with the same crank and rods.

Bob

cdscarab

Replace the rod bolts with the best you can afford. REAL CHEAP insurance!
When I had my 535 (750hp) redone, I asked if the bolts shouldn't be replaced. After checking, all were found to have been severely strechted and they were ARPs best.
Their the most stressed fastener in the motor, don't be cheap.

PatriYacht

Thanks for the info Smitty. I always learn something from your analysis. Ian

Old Navy

So, is there any update on this. Curious if that blower failure was the cause?

articfriends

Pulled even side cyl head saturday,#8 cylinder has a "rough" finish about 1/2 way down bore on the back 1/4 of surface,if you run your nail over it it catches,almost like it had gotten rusted at one time in past 2 years then burnished the rust off,cross hatch still there on the other 3/4's of the cylinder and the other 3 look perfect. Will know more next saturday when I have free time to rip motor down to parade rest. I can't believe the leakdown wasn't much worse,Smitty

articfriends

Got motor tore completely down last night,#7 cylinder which had perfect compression and leakdown numbers, had pushed the top layer of the head gasket out from the fire ring all the way into the valley. The only thing left sealing the cylinder was the fire ring around the cylinder so it was DEFINATELY time. The bottom sides of the pistons had very little of the burn't,varnished looking stains on the bottom that they have had in the past,I would attribute that to the ceramic coating on top of the pistons from swain tech. The coating on the skirts was wore about 1/3 of the way thru to the actual skirt. The rod and main bearings looked like brand new with virtually no wear (h-series clevite 77's),the crank looked perfect too,zero scratched anywhere. The heads must have been walking around a little,the dowel sleeves that hold them in alignment fell out of the block when I pulled them off,they usually have to be pried out. The hardin marine pan has some blistering towards the front inside where the paint is bubbling but hasn't actually peeled or came off,not sure what I'm going to do for that.All the cylinders have sorta a staining or spotting down low as if moisture fron the oil when the motor was shut down after running steamed up and rusted the cylinders slightly,#8 had this where you could see it while still assembled,the others you can see it now that I have the pistons out. I'm sending the rods and crank out to be checked for cracks. I'm going to put another set of arp 2000 rod bolts in the rods as they have worked perfect so far. I'll have the block honed to see if it can stay at 4.500 1 more time. My AFR heads have provisions for the extra bolts that clamp in the valley,I'm going to find a local shop that can install the bosses on the lifter valley part of my block (merlin 2) then have it decked again,I didn't zero deck it in the beginning just for this very reason,I measured the deck height as I tore it down and I have about 10-11 thous to work with and can still run std height pistons,I'd be screewed if I had went right to zero the first or second time (this is round 3 for this block). I'm having the heads slightly ported on the exhaust side,rm builder is tweaking my cam profile ever so slightly and I'm having a spare throttle body modified. I'm looking to bring the hp peak from the 950 ish it made at 5600-5700 closer to high 9's near 6000 without giving up what I already have or re-doing my whole engine program which is working quite well. Time to start ordering parts and getting some nmachine work done,Smitty

articfriends

I didn't see any evidence of any "grit" or metal that had went thru the motor from wiping out the procharger last summer,Smitty

articfriends

Motor is coming along,exhaust valves had tiny lines that look like cracks on the back sides (inconel ferrera's),have new ones ordered,not sure if motor was lean at one point or if it was reversion of some kind but it was all eight. Been trying to solve the head gasket almost being blown dilema,paper was pushed out on #7 cylinder ,fire ring was only thing left sealing the cylinder,it still had 4-5% leakdown and perfect compression. I bought a set of rehr-morrison head bolt stud bosses to add to the lifter valley on my merlin 2 block,had hard time finding someone to install them. Finally found a shop familar with doing it locally that could do it this century,machinist would only use the gellner stud boss kit,it actually looked like it would pull more evenly so I agreed to use his choice of brand. Today after 3 weeks he told me the amount of metal that would be required to install the extra stud bosses would make block junk,gellner told him kit couldn't be installed on a merlin 2. Tired of pizzing around and I don't want to chance lifting a head gasket in next 2 years so I ordrerd a new dart big m block that has the extra head bolt stud bosses built into the block,hate to start over because merlin block was still pefect and seasoned but I'm not getting anywhere with finishing this project this summer if I don't do something (anyone looking for a 4.500/9.800 merlin 2 w/studed mains?). Pistons are back from swain tech,re-coated ready to run,crank and rods are done too,they were still like new. Machine shop is going to cook new block in oven for 25 or 30 heat cylces for a week plus to season it before doing all the final re-machining (all the machine work from dart and merlin is done green and about worthless and usually waay off out of the box,I been thru this once before). Smitty