Preparing for SuperChargers
 

I started tearing down my 600HP 454's. I have 4 seasons on these engines and I run them up to 6300RPM quite regularly. I have always referred to them as my high strung 454's but all in all they have been great, mild mannered engines. They idle at 600RPM with 35* locked out timing.

This winter I am going to pull my solid roller cams and put in some blower friendly cams. As of now they are 9.6:1, with SRP small dome pistons that are 0.014" in the hole, Valako Pro1 heads, Isky Solid lifters, Crane HI-6M ignitions and Barry Grant (Holley) 750's. I have a pair of B&M 250's that I plan on putting on the top of these mills.

I plan on dynoing N/A with the new cams and then with the blower on. I will probably first run them in the boat without the blowers and then add them later in the season.

I popped off Main cap #2 to take a look at the bearing and crank. I have a shiny witness spot running through the middle of the bearing. Nothing that I can feel with my nail at all. It also appears that there is a matching witness on the crank, also nothing that is noticeable by the touch.

I plan on pulling a couple of rod caps to check also.

It always seems that harmonic balancers do not want to come off. So I marked it, tightened up the puller bolt and come back in 5 mins to see if it had move. Hallelujah it moved!! I did not run a cam retaining plate but used a cam button. Apparently the cam has been walking forward into the timing chain cover. This was also wearing the button down and probably why I would lose timing over the years. *Note* get retaining plates. The cam looked great and no wear on the cam bearing.

All looked surprisingly good except the cam button.

If anyone has any suggestions or comments as always they are more than welcome.

Weld a hardened washer to your timing cover for the cam button to run into and use a good cam button.

Cam walk
 

I don't know if this is bought piece or not but the 540s I got have a nifty adjustable brace for the cam. Randy

i like the edelbrock aluminum tc covers,and i use a thrust bumper from small block chevy,requires very little shimming to get correct cam end play.

ahhh yes,your standard post,very informative,as usual.:lolhit::lolhit:

+1 When I first realized that the cam was deflecting the timing chain cover I machined aluminum plates to sandwich between the cover and my Stainless Marine crossover.

I run cast alum timing covers and cam buttons with needle bearings. With about .005 clearance between the button and cover I get zero wear on the alum cover. There are some polish marks but thats it. You must not have had the clearance set up right on the button (too tight).

I'm looking forward to seeing what you can get out of your panther with the blowers. What kind of top end are you getting now?

78.7 on the river was the fastest I have seen. What I want to see is if I get my power band down, and get TQ & HP closer together even with less HP if I will actually go faster. My engines made peak TQ @ 5200RPM and peak HP at 6500RPM. This might have been a better combination with a smaller lightweight efficient hull boat and not the TRS slug I have.

Jason, are you keeping those pistons? If so I'd keep the boost around 3.5-4.5 lb and good fuel. Even with a measly 3-4lbs of boost, I wouldn't be surprised to see easy 100-125hp gain over what you have . You can do more with some meth injection or race fuel. I think your cam selection will play a big factor in what you can do on the pump.

Nice choice! I wish I had the money for 2x B&M's are you going single or dual carb setup?

I plan on using my existing pistons. I called JE and talked to one of their engineers. He said the small dome pistons I have I could cut the domes off to the desired cc I wanted because they were solid dome pistons. He also told me 2.68g/cc if I cut the domes off. If they were hollow dome pistons he gave me his recommended minimum dome thicknesses dimensions N/A vs boosted.

Did you ask that because they are not flat tops or because of the compression ratio? I am going get the CR down. I don't want to run more than 5psi.

I actually have 6 carbs right now. 4 4150 Barry Grant Holley's and 2 1050 dominators. I have the setups for both and would like to dyno both setups.

Hard to tell in the pictures, but you appear to have a couple of exhaust valves running a little leaner than the rest of them. Probably OK if they are tan instead of white, and your fuel mixture distribution will be totally different with the supercharger.

I flycut my pistons to get the static cr to 9.25 and run 6# boost. I shoot for a dynamic cr of 8.0-8.1 with my crane 731 cam straight up.

Did anyone ever make a -2 trs lower? That would help you immensley on the top end.

FWIW, I run 5300-5400rpm 1:5ratio drives w 32p bravos to get my best speeds. You might be right about lowering your power band to gain top end. I think the longer strakes will help as well since your CG is so far back with the trs setup.

My AFR's are 11.8-12. I have bungs in all 4 tails. I was thinking that the discoloration was actually due to the little bit of reversion I have. I have over a 1 mile idle back to the dock. I had a little bit of water in the manifolds. It's hard to believe that you can pull water 3' back through dry to the tip TRS tail pipes. This should also be corrected with the new cams. Note cams on a 108* may cause reversion. lol

Not that I know of. But they do make a +1" and +2" in case you need to do some dredging at your local launch.

rookie,what is the distance from the top of the piston,not the dome,to the top of the first ringland?

I'd need to measure that. Part #212137
Looks like there is quite a bit of stock.
http://www.jepistons.com/Catalogs/SR...dome_open.aspx

Open up the chamber on your heads some to drop the CR more.

+1
Yup, having JimV do a chamber port was in the plans. I still haven't deducted the volume for my bore notch, pistons -0.014" in the hole, head gaskets and stuff. I don't think I will have much trouble getting to 9.0 or below. The last resort was to cut the pistons, but I really don't want to take the engines down any further.

Anyone have any opinions on the polished witness on the bearing? There was some Right Stuff in the bottom of the oil pan and in the screen of the oil pump.

Roller cam buttons?
http://www.jegs.com/i/Comp+Cams/249/...Fe5FMgodGjAAlw

rookie,it looks like a small amount of dirt went through the bearing,those are the cam button,s i like to use.i think i would have the piston,s flycut before i changed the cc on heads.be careful with your tune,keep it fat,im not sure how much heat that piston will tolerate with a blower .what length rods do you have? im guessing 6.135.

Intercoolers????

Yes 6.135" Just going to have some material removed around the ex valves. Then get a total head volume.
No, I don't plan on spinning them that hard. And I see innercoolers as a catch 22. Put on a restriction to cool a charge then have to spin them harder to make up for the restriction that was just added and then add more heat to the charge you just tried to cool.
I have a dual probe handheld pyrometer and I will measure charge temp delta above and below blower.

Please post the results of the pyro temps when you get it set up, interested to set the differencial, I ran a similar roots blower back in 1989 at 5lbs boost, really started heating up at 5200 rpms for a 3 min blast, added water/alcohol injection to help. I know they have made many advancements in blower technology since then, but I hate the thought of backing off the timing due to a heated air charge. but as most modifications go it becomes a trade off. Keep us posted, sounds like a sweet project!

No, I don't plan on spinning them that hard. And I see innercoolers as a catch 22. Put on a restriction to cool a charge then have to spin them harder to make up for the restriction that was just added and then add more heat to the charge you just tried to cool.
I have a dual probe handheld pyrometer and I will measure charge temp delta above and below blower.[/QUOTE]

I think if you do your home work you will fined that intercoolers are anything but a catch 22. It's the easiest HP gain you can make. :whistle:

.[/QUOTE]

I think if you do your home work you will fined that intercoolers are anything but a catch 22. It's the easiest HP gain you can make. :whistle:[/QUOTE]

I would like to see the results of his test, only thing better would be to bolt a intercooler on and then do a pull, making note of hp and temp changes.

I think a intercooler might be worth some power on a small blower overdriven a lot. But with a big blower under driven , there just isn't much heat made at marine roots boost levels 5-7lbs. I'd rather not make the heat nor have the restriction, vs make the heat, add a cooler, turn blower faster, etc.

Many guys used to bolt chillers on the baby blower merc motors. Nothing gained until pulleys changed to spin blower harder, then maybe 2-3mph, with an extra 2lbs of boost.

I swapped from a single carb non intercooled 250 blower to a dual carb non intercooled 420 blower. Boat gained 4-5mph running 1lb less boost than I was with the 250. You can see where 7% under will run cooler than 80% overdriven.

I think if you do your home work you will fined that intercoolers are anything but a catch 22. It's the easiest HP gain you can make. :whistle:[/QUOTE]

I would like to see the results of his test, only thing better would be to bolt a intercooler on and then do a pull, making note of hp and temp changes.

I think a intercooler might be worth some power on a small blower overdriven a lot. But with a big blower under driven , there just isn't much heat made at marine roots boost levels 5-7lbs. I'd rather not make the heat nor have the restriction, vs make the heat, add a cooler, turn blower faster, etc.

Many guys used to bolt chillers on the baby blower merc motors. Nothing gained until pulleys changed to spin blower harder, then maybe 2-3mph, with an extra 2lbs of boost.

I swapped from a single carb non intercooled 250 blower to a dual carb non intercooled 420 blower. Boat gained 4-5mph running 1lb less boost than I was with the 250. You can see where 7% under will run cooler than 80% overdriven.[/QUOTE]

Good points and perspective. I also would like to see some hard data for the results. I am still a little leary of bolting a intercooler on top of the engine with the potential for cooler leakage via wear or damage. At some point though you have to factor the inefficiency (rotor leakage) of a large blower at low boost to make the HP you are looking for.

I think the rotor leakage can be a issue in say a street application, where low speed torque is really needed.

For example, a 250 blower might outperform a 420 until say 5000rpm from a torque standpoint. But in marine, the larger blower at sustained high engine rpm works better. You'll get more leakage at say 3500 rpm, but it's minimal compared to the gains you get say at wot from the cooler air charge from the larger blower turning slower.

As witnessed by many on the old 525sc with the 177's, upping the boost from 5 to 7 lbs, gained very little. It just adds more heat and shorter blower life.

Thats the buttons I use. You can take them apart at the snap ring and surface grind/turn the fat end to get the clearance/cam play right where you like it. The bearing wear is from debris of some sort, probably not the right stuff but a dirty cooler or a small amount of metal in the galleys. You might cut apart the oil filter to get a better look but all in all no worries too big there in my estimation.

With that theroy, not saying your wrong, in fact I agree to an extent, but you have ask youself how much am I going to run wot and for how long at wot as well I guess. If you do the majority of your boating at "cruise" rpms then the above issue could still be a possibility I would think?

I see what you're getting at. I think most guys when doing upgrades, look for one result out of their mods, top speed gains. The ability to turn a higher pitch prop at wot, just means better cruise speed. For example, lets say a large blower setup can turn a 30p prop to 5500. and The small blower set can turn a 28p prop to 5500. The larger blower setup will also cruise faster at say 3500 with the taller prop. We normally prop out boats for wot rpm range, and the midrange kinda is what it is

let's not forget the OP is not going with the 420s he is installig te 250s, and i'll bet the perfomance will be addictive! so the throttle will begin to be pushed to WOT more and more, for longer and longer, isn't that what we do? I think it is a great project, and just wanted to see OPs thought concerning the intercoolers. Either way he will love the power gain.

I agree. Plus we were getting off track a bit. I'd love to bring one of my 420 blowers up for the dyno session though. Since It would bolt on to his intake, and just require some pulley swapping, which I have extras. That would be pretty cool, just wish I lived a little closer to rookie. Kind of a supercharger shoot out , maybe even bolt chillers on and off. Really give his engine a workout!!!

Not getting off track at all. That's why I posted this in the tech section and not on my restoration/upgrade thread. This is what the forum is all about.

Exactly! We all want the big hp and top end numbers or at least think we do, but is it REALLY what we are looking for? Just my perspective. Is midrange where its at?

Where do you dyno and how much $$$ to dyno? I have a truck and time, just not a ton of $$$.

I hear that! Place I dynoed mine is in Joliet, IL. They have a DTS dyno. I want to say I paid 500 bucks.

It really wouldn't be much for me to pop a blower off, and I also have complete drive setups, basically its the setup that merc used on the 600sc. We would need to remove your tensioner and crank pulley, and bolt my crank pulley on. My tensioner mounts to the blower snout. In reality probably faster than changing jets. With my setup, its a 10rib belt deal, and pulleys made 6.5psi on my 468's. But, if we can get our hands on a couple 16 rib pulleys for the megablower, we can bolt them on the blower and still run the 10 rib setup, it works. Just to try different ratios.

When you gonna have it built and ready?