My rapido longblock (pics)

[RCSConstruction]

Re: My rapido longblock (pics)

Those water passage inserts are not needed. They will rust out anyhow..
Did you use some RTV at the corners of the intake manifold? I never did like using those rubber seals, I always use RTV all the way across.
Have you pressure tested those exhaust manifolds? Are they known 100% sure to be in good shape? One crack in them and your motor will be toast in short order.
Not having the windage tray MAY cause aeration of the oil and your lifters may not pump up correctly causing the valves to "tick". Pans with built in windage tray and scrapers are great but expensive.
That front timing cover may not last very long if your in salt water.

Thats a good days work, great job!

 

[erikgreen]

Re: My rapido longblock (pics)

Yes, I used just a little RTV on that one water passage. The others looked ok to me..

I was kind of upset that the only timing cover the shop had was the chromed one. Cost me $10 more than a plain one, and I had to buy the timing tab separate. I'm a fresh water only guy, so I hope I'm ok with that.

Good to know on the water passages, I'll just go with what I've got on the motor right now then.

Just a bit more work on the motor and I'm ready to mount it in the boat... woo!

Erik

 

[RCSConstruction]

Re: My rapido longblock (pics)

Yes, I used just a little RTV on that one water passage. The others looked ok to me..



Erik

I was talking about the four corners where the rubber seal meets the intake gaskets.

 

[jayzad]

Re: My rapido longblock (pics)

Here is just two cents from a rookie when it comes to boat repair. Maybe this has already been mentioned in this long post, but you have to watch out sometimes when it comes to certain terms, like Rebuilt, Factory rebuilt, Remanufactured, Reconditioned, Overhauled, and so on. I think technically they all could mean different things to different people.

Of course good luck.

 

[ParallaxBill]

Re: My rapido longblock (pics)

After hot rodding my share of sb Chevys, the reason for the 1/4-1/2 turn from zero lash was in reference to pumped up lifters due to over revving. Pre-loading them 1/4-1/2 turn allowed a much quicker bleed down rate (return of normal plunger position in the valve body) if pump up did occur. It's a well known Chevy hot rodders trick which let the builder avoid expensive and mostly useless high bleed rate lifters.

1/4-1/2-3/4-1 whole turn works fine for most any SB chevy marine application too. There's a lot of wiggle room with chevy lifter adjustments for most applications. Plus you shouldn't be missing any gears in your boat that would let you over spin your motor. You might do it from cavitation but if you know what you are doing that shouldn't be a problem.

Just my .02 based on 35 years of chevy small block experience.

 

[ParallaxBill]

Re: My rapido longblock (pics)

Another good Chevy small block builders tip.

Most folks these days ditch the factory rubber (not that reliable) engine valley intake gaskets and run a 3/16" -1/4" bead of gas and oil resistant RTV in their place for a better seal. To do it right with the RTV just run a nice even bead, then let it "skin over" before carefully setting the intake in place. Make sure you get some up on the ends of the regular intake gasket tabs to prevent leaks in those corners.

 

[Gary H NC]

Re: My rapido longblock (pics)

I was talking about the four corners where the rubber seal meets the intake gaskets.

And they WILL leak without some sealant in those corners.I never use the rubber front and rear lip gasket.That Napa spray can of black sealant is perfect for those.I forget the name of it but its comes out of the can like that canned cheese for your crackers does..

 

[John_S]

Re: My rapido longblock (pics)

"Most folks these days ditch the factory rubber (not that reliable) engine valley intake gaskets and run a 3/16" -1/4" bead of gas and oil resistant RTV in their place for a better seal. "

And that is what Merc recommends as well. There was only gray rtv on my stock intake manifold, no rubber gaskets. And rtv is all I used on the new manifold.

 

[erikgreen]

Re: My rapido longblock (pics)

Well, live and learn. I actually used RTV in those areas to seal around the rubber gasket - the gasket looked like it was too poorly fit to work alone. If I'd known to not use them I would have. I think with the RTV it'll seal ok, but we'll see.

Day 2 of assembly today - no real new pics, just a bit of work to get the belts (new) to fit, some new plugs, a couple of bolts, and a problem with the temperature sender (corrosion). I also switched to a 1-wire alternator from the 3-wire automotive one I had.

Plus we spent time getting the boat's transom back together.

More pics when we do the install, probably next weekend but maybe during the week.

Erik

 

[cjames]

Re: My rapido longblock (pics)

In responce to the early posts regarding lifters--too loose and a little noisy is much better than too tight, and hanging open. Being a diesel guy, and building ALL my hot rod gas engines with solid lifters, I still dont 100% trust hydraulic lifters to 'take care of themselfs'. With any lifters, a good valve adjustment MUST be done (imho) before sea trial, AND after cam break in. Listen to the engine builder, do exactly as he says.

 

[MikDee]

Re: My rapido longblock (pics)

I worked at a GM engine lab testing engines for a few years, and they taught me to turn the push rod between my fingers with the valve closed and engine not running until the push rod stopped turning. Than one complete turn. This was done on all V8's. Also this was where they built the engines until they closed the plant down.

I've tried this method, and the lifting the pushrod up, & down method, ended up with valves out of adjustment, Maybe on a brand new engine, with all nice shiny new parts, and no wear, or built up gunk, but not on used, or rebuilt engines, from my experience. My final adjustment comes with the car warmed up, & running, and following the clicking.

 

[MikDee]

Re: My rapido longblock (pics)

The actual spec is 1 to 1.5 turns.
The reason takes a little time to explain, but there is a good reason for it. The internal plunger in the lifter has .120" total travel and the plunger is what allows the hydraulic lifter to adjust the valves and compensate for different operating conditions. The objective of setting the valve lash is to position this plunger in the center of its travel--appr. .060" down in its bore. The top threads on the rocker studs are 24 per inch, so 1 inch divided by 24= .041".
Therefore 1 turn of the adjusting nut move the plunger .041" down in its bore and 1.5 turns = .060" down. The reason so many people waste so much time fooling with hydraulic valve is nobody takes the time to understand what exactly is going on and adjust them properly. 1/4 to 1/2 turn will do the job of making the valve quiet, but the adjustment won't last as long as if it were done properly. And every manual you will read anywhere by anybody will tell you to adjust the valves statically(engine off) not dynamically(engine running). It a poor way of cutting corners and not taking the time to do the job right.
--
Stan
--
Stan

IMO, Baloney! You can't get a proper setting statically with a cold engine, that's not under load, or moving! I don't care what the book says, By the way, I think the static way is cutting corners! and on a good motor, I've never had a problem with a valve lifter getting loose, prematurely at 1/2 turn down on any small block chevy.

 

[MikDee]

Re: My rapido longblock (pics)

Well, I went out on the net to get re-educated on a hyd lifter works. I like it when a forum topic does that!

Also, went reading through similiar info on car forums. From that reading, it appears that what you gain by going less than 1 full turn, is some higher headroom before valve float. You may gain a couple hundred rpms before float. I found one reference to stock floating at 5700rpms. That basicly jives with my memory of hyd lifters being OK to around 6K.

Since our boat engines won't see above 5K, I am not seeing any benefit by deviating from the Merc spec.

I had a 62' Impala SS 327/300hp, and it would regularly rev to 7,000 rpm with no lifter float! But, even tho the mech. technology was great even back then, the points would float, and wires, & plugs, would give out causing it to start breaking up, usually above 5-6k rpm. (Thank God for HEI) If you read the small block Chevy book, their 327/350hp, & 350/350hp, factory cams were capable of developing power to 7k rpm, and the matching lifters were capable of sustaining it, but you also need the correct springs.

 

[MikDee]

Re: My rapido longblock (pics)

Those water passage inserts are not needed. They will rust out anyhow..
Did you use some RTV at the corners of the intake manifold? I never did like using those rubber seals, I always use RTV all the way across.
Have you pressure tested those exhaust manifolds? Are they known 100% sure to be in good shape? One crack in them and your motor will be toast in short order.
Not having the windage tray MAY cause aeration of the oil and your lifters may not pump up correctly causing the valves to "tick". Pans with built in windage tray and scrapers are great but expensive.
That front timing cover may not last very long if your in salt water.

Thats a good days work, great job!

From what I've read, a windage tray on the small block Chevy was to keep the oil in the pan at over 6,000 rpm! I have no idea what it's doing on a boat? Unless they had another reason for it?

By the way, noticed you've got the old "log style" exhaust manifolds, they don't look newish? A set of the later model center riser manifolds, and risers would be more efficient, and maybe worth the cost for a safety factor (no rust out) also, I saw them on ebay new with a total of $369. for everything.

 

[SuperNova]

Re: My rapido longblock (pics)

I appreciate your OPINION there, mikdee, but unfortunately that is all it is, there is no practical experience or real thought behind it. Book smart is easy, I can read about things as well as you can, but I also have been building small block chevy's for appr 22 yrs now and I can tell you what works short term (your ideas) and what works long term in the real world (the actual facts). Unless you've built a motor and watched it live out to 100,000 miles trouble free or 1500 hours trouble free, you don't REALLY know what you are talking about. Just MY opinion.
--
Stan

 

[SuperNova]

Re: My rapido longblock (pics)

I had a 62' Impala SS 327/300hp, and it would regularly rev to 7,000 rpm with no lifter float! But, even tho the mech. technology was great even back then, the points would float, and wires, & plugs, would give out causing it to start breaking up, usually above 5-6k rpm. (Thank God for HEI) If you read the small block Chevy book, their 327/350hp, & 350/350hp, factory cams were capable of developing power to 7k rpm, and the matching lifters were capable of sustaining it, but you also need the correct springs.

Most of those older cars ran solid lifters, and I would LOVE to watch you adjust one of those dynamically!!!! And is that "the small block chevy book" or is it "THE smallblock chevy book" , as I didn't realize there was only one book on the small block chevy. Maybe in your library.

 

[John_S]

Re: My rapido longblock (pics)

OK, as far as this particular discussion goes, the poster should adjust the lifter to the rebuilders instruction. Otherwise, might be subject to warrentee contention.

As far as the 1/4 vs 1 turn, I haven't heard of any performance improvement, that benefits either. Don't think there is one, given the rpm range we are talking. Also keep in mind, since ThunderboltV you can't rev your stock merc much past 5K anyway (rev limiter). Volvo probably has something similiar.

The difference seems to be in how much component wear the lifter can adjust for. Now, you could go figure out how much normal wear and heat expansion will change the length of the valve train components, and figure out which has a more benefit, to position down within lifter. Even with that data, there could still be factors that "we" are not taking into consideration. Such as oil pressure and temp over time. Anyone that thinks they know more than GM, Merc, or Volvo engineers, on standard production engines, is very dilusional.

Static vs Dynamic adjustment, to each their own. You can rest assured that if you follow the mfg procedure for either, all will be well.

 

[John_S]

Re: My rapido longblock (pics)

"I had a 62' Impala SS 327/300hp, and it would regularly rev to 7,000 rpm with no lifter float! But, even tho the mech. technology was great even back then, the points would float, and wires, & plugs, would give out causing it to start breaking up, usually above 5-6k rpm. (Thank God for HEI) If you read the small block Chevy book, their 327/350hp, & 350/350hp, factory cams were capable of developing power to 7k rpm, and the matching lifters were capable of sustaining it, but you also need the correct springs."

Well, you not the only one on the board that had early SBC experience. For myself, it was a '70 Nova SS w/350. Now it was strong upto 6K. Between 6-7K it would start to break-down. Now, after all this time, I couldn't tell you if it was ignition break-down, valve float or other reason. FWIW, this was a 300HP 350 that had a number of the LT1 parts on it. It did have the hyd lifters. The 6K limit was a "general" rule of thumb, that I remembered from that timeframe. Now, when I looked around the net, there are speciality hyd lifters that may be good to 7K, but most racers seem to be anchored with solid lifters.

Now, can you tell me that valve float, or ignition break-down is a concern with our production marine engines running 5K and under? Do you have a better explaination on where the 1/4 - 1/2 adjustment came from and why it is important on a marine engine?

 

[KaGee]

Re: My rapido longblock (pics)

For the record... the procedure as noted by Imported John and brought up by me earlier in this thread is exactly how they describe it in my OMC FACTORY manual.

Now... back to the topic.

 

[Buttanic]

Re: My rapido longblock (pics)

From what I've read, a windage tray on the small block Chevy was to keep the oil in the pan at over 6,000 rpm! I have no idea what it's doing on a boat? Unless they had another reason for it?

By the way, noticed you've got the old "log style" exhaust manifolds, they don't look newish? A set of the later model center riser manifolds, and risers would be more efficient, and maybe worth the cost for a safety factor (no rust out) also, I saw them on ebay new with a total of $369. for everything.

You don't think a boat bouncing off of waves is splashing oil all over the pan and up into the crank.