Cam intensity question
05-31-2015, 07:16 PM
#41
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05-31-2015, 07:37 PM
#42
Platinum Member
i am thinking about building a 15-1 compression ratio,huge cam,big chief headed n/a engine for a 24 foot baja that is for sale on ebay,it should make 1000 hp and need valve train maintenance every 25 hrs but who cares about little things like that.i am going to use neo oil in the alfa drive so it should hold up well.i am going to run it on e85 so fuel won,t be to expensive.the ebay add said the transom is soft but i think some super glue will bring it back to snuff.my question is will the 23 pitch aluminum prop that comes with the boat work or will i need one of those high priced stainless steel 4 blade props.one more question,will my s10 pickup pull my new boat ok?i only live about 40 miles from the canal i plan on running it in.
05-31-2015, 07:55 PM
#43
i am thinking about building a 15-1 compression ratio,huge cam,big chief headed n/a engine for a 24 foot baja that is for sale on ebay,it should make 1000 hp and need valve train maintenance every 25 hrs but who cares about little things like that.i am going to use neo oil in the alfa drive so it should hold up well.i am going to run it on e85 so fuel won,t be to expensive.the ebay add said the transom is soft but i think some super glue will bring it back to snuff.my question is will the 23 pitch aluminum prop that comes with the boat work or will i need one of those high priced stainless steel 4 blade props.one more question,will my s10 pickup pull my new boat ok?i only live about 40 miles from the canal i plan on running it in.
Also going to use the new reverse radius peanut shaped cam lobes to go along with my peanut butter ports in my cast iron heads. That should work well with that 15:1 CR.
Mike, I think that soft transom will work to your advantage - it will give the needed flex to keep you from braking your Alfalfa drive.
05-31-2015, 08:10 PM
#45
I have never used them yet I am rounding parts up to finish the project. We will see how they hold up its a little scary. Camshaft has .500 lobe on intake with 1.7 rocker. Titanium intake this time around it would never work with a stainless intake valve way to heavy for big rpm. I did see in my last build with the head hunters brodix heads the intake ramp on camshaft was not holding up to good it had 2.400 valve about 5 seasons on camshaft and it was junk. I think if it had titanium intake valves would of bin no problem or 55mm and .937 lifters.
05-31-2015, 08:14 PM
#46
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iTrader: (1)
What about Prolong or that Super Oil Concentrate stuff ? Or...just pour in a gallon of chlorinebleach ? They all excell in 30 sec wear tests. 
05-31-2015, 08:23 PM
#47
I have never used them yet I am rounding parts up to finish the project. We will see how they hold up its a little scary. Camshaft has .500 lobe on intake with 1.7 rocker. Titanium intake this time around it would never work with a stainless intake valve way to heavy for big rpm. I did see in my last build with the head hunters brodix heads the intake ramp on camshaft was not holding up to good it had 2.400 valve about 5 seasons on camshaft and it was junk. I think if it had titanium intake valves would of bin no problem or 55mm and .937 lifters.
I do bet that thing sounded good around the dock with those in the apache!
05-31-2015, 08:41 PM
#48
The last time I ran the boat it had .440 lobes with 1.75 rockers and made good power sounded good around the dock but having 45* ignition advance calms it down a lot at idle without the extra advance it would piss people off bad. Spring pressure on old cams was 210. new cams about 240 maybe could use less but did not do spintron. So that's where I stand.
06-01-2015, 08:23 AM
#50
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Dan Jesel: Jesel has built rockers with ratios upwards of the 2.4:1, primarily for flat-tappet systems and in some cases because of cam lift rules, but it depends on the total motor package including the limitations imposed by the engine block and the sanctioning body rules. Jesel prefers to use larger diameter cams and larger cam lobes with lower rocker ratios. Higher rocker ratios increase the valve opening rates, but by using larger cams and lobes you can end up with similar opening rates while lowering the loads and stresses on the valve train. Cam diameters are limited by the amount of material surrounding the cam tunnel. Some cam tunnels can only be bored out to 68mm, however many NHRA Pro Stock blocks can be bored out to 82mm. Then you have the rules — some sanctioning bodies limit the cam size so in order to get more lift or loft they must use a higher ratio rocker to achieve that. There is a noticeable difference when turning over a motor with the two different packages — small cam with high ratio rocker vs. big cam lobe with lower ratio rockers. It takes more rotational force to move the high rocker ratio package, and this required force (or drag) increases with rpm. It is our experience that the large lobe/low rocker ratio package provides a smoother, more stable valve train capable of more rpm and providing better durabilit
