Crane 168731 reversion?
 

Has anyone used a Crane 168731 with Gil Magnum Choice exhaust? Did you have any problems with water reversion?

I have installed this cam in more motors than I can remember and never had a reversion issue. It is a great cam for a decent bump, but to get a good benifit from it, you need to be able to turn the motor up to at least 6000 rpm. Twisting the motor to 5000 is only going to net you something like 75% of the cam. Also, if you decide to go to the 741 cam, it will bejust like the 731 and be trouble free regardless of what exhaust you run. You're good.

The 731 cam in a 454 wont need 6000RPM to perform. The 741 cam, maybe close.

The 731 is 226/236 on a 112LSA. The 731 is a nice fit for a mildly built 454.

Keep in mind these cams are gen VI stepped nose cams. I thought I remember you said you had a dart block, I believe your block would take a mark iv/gen v style cam.

Mine is a Dart block. I'm trying to keep the cost down as well so I'm trying to decide if I should do a roller setup or stay flat tappet. Engine specs are as follows. Dart big M .020 over, weiland dual plane intake, 9.2:1 compression ratio and dart iron eagle 308 heads.

Your compression is down alittle to be running the 731 cam but maybe not enough to be an issue. Expense wise, if you cant seet the spring height for the roller cam, then you are probably going to be looking at something in the $1500.00 range to go with a roller setup. You will need the cam, lifters and springs. If this blows a hole in your budget, then I suggest that you look at a Comp Cams flat tappet setup. This one, http://www.summitracing.com/parts/cca-k11-232-3 will fit your budget and it is also in your compression range. If you want to bump it up alittle, then this one would work great for you... http://www.summitracing.com/parts/cca-k11-240-4 . The 240-4 cam is just above your compression but not enough to matter. In a 454, either cam will give it some attitude around the docks and at an idle, but not enough attitude to become a pain in the butt. Good luck.

cmon, that first cam you recommend is comparable to a stock 454 MAG 365HP cam!!! 218/224* of duration....The stock mercruiser 420HP 454 used a 228/236 530/551 lift 114 lsa flat tappet, with 8.8:1 compression. You are suggesting a much milder flat tappet for his 454, when he's seeking 500hp.

The 731 cam will work just FINE with 9.2:1 compression in his 454. Mercury used a similar cam in their 500EFI, with under 9:1 compression, and a even more aggressive profile in the 525EFI, again, with under 9:1 compression.

218/224*.......its not going in his RV, its going in his boat. No point in sticking a cam that will run out of breath at 4800- 5000 in it.

Word!:poopoo:

He doesnt have a 420 HP 454 and the cam I suggested is ALOT bigger then the stocker cam in it from Mercruiser. Besides that you might want to look at the price of the cam you are talking about...if you can find one. You are not going to get 500 HP from a cam swap alone in a 454. He said he had a budget and his motor doesnt have a roller in it now so to go to the 731 it is going to be expensive. he has to get "retro-fit" roller lifters since he cant get a spider plate and the retro roller lifters are going to cost him around $600.00. How many motors have you put together? You really need to look at and understand the cam spec sheet rather than go off what you read on Summit...There is a lot of differences. I build them almost daily and I gave him the information that has worked for many of my customers that were also on a budget. He can do whatever he wants but if he does it wrong he gets to do it all over again.

The 731 works perfectly fine in a 454. I used it in my 525SC. Idles at about 800rpms.
The 9.2 Comp ratio is fine. Spin it to about 5400rpms and you're good to go.
The 731 is just very slightly larger than a 500efi cam.

Ya Mild Thunder, I bet you don't even have a "magic room"!
Lmao! Where do you do all your machine work shooter?? :lolhit:

[YOUTUBE]http://www.youtube.com/watch?v=BMOKvhPis_U&list=PLm2Lymo6NjpCLpJZuoMcGDSF 7nyhyr0hK&index=8[/YOUTUBE]

Thank you for all the input guys. Do you know if all the cams suggested will work with my Dart block? Someone earlier in the thread mentioned I might need a cam that will work with a mark IV block. Can anyone confirm that?

Alex,
I would have expected a little better facility from you with all your knowledge...just kidding I know whose mega shop that is. We all had to start somewhere, when I was 15 I would have been proud enough of that set up to post a video (on 8mm) for the world to see. I do believe that room is better known as the 540 kissy/huggy room.

The cams I listed for you will work in your Dart block. The 168731 cam will not. If you want this cam for your Dart block then try to find a 139731 (if you can find one) or139011, which is the same thing with a new number.

[QUOTE=pslonaker;3913944]He doesnt have a 420 HP 454 and the cam I suggested is ALOT bigger then the stocker cam in it from Mercruiser. Besides that you might want to look at the price of the cam you are talking about...if you can find one. You are not going to get 500 HP from a cam swap alone in a 454. [QUOTE]

Well, definitely not gonna see 500HP with your cam recommendation!! Probably not even 400HP with that sweet entry level 218/224 .500 lift flat tappet. Nice little upgrade for a merc 330HP 454. Not the cam that belongs in a 454 with Dart heads, 9.2:1 compression, forged rotator, and good intake, carb and exhaust. 500HP is very doable, he has the parts, just needs the proper cam setup, intake and carbs. Slapping that cam you suggested in there combined with those dart 308 heads, is like putting a 4cyl in a corvette. Those Dart's 308's are plenty capable for 500+hp.

You say you used that cam in many customers boats with great results. Well, lets see the dyno sheet? How much power you making with that rv cam?

Pslonakler's cam recommendation. Not sure what cam he's reffering this one is MUCH bigger than.

http://www.compcams.com/Company/CC/c...?csid=403&sb=2

Stock 454 400HP, 420HP cam.

http://www.cranecams.com/product/car...detail&p=24005

zx6rr33, oso used to be a great place to get good cam info. Nowdays, you might as well post your questions on the Martha stewart cooking forum, and probably get better recommendations than what you'll get from guys like pslonaker.

Obviously your not getting the answers here. Do yourself a favor and give bob madera from Marine Kinetics a call. Bob will set you up with everything you need, with real world expectations and results.

now thats some funny chit right there,pole smoker telling mild thunder[mr research]about cams,mild has forgotten more about engine building than smoker will ever know.polesmoker,you are a legend in your own mind.better answer the phone smoker,it,s chubby calling.

Magic Room!! LMAO

X2! If you want a cam that is right for your specific application, and makes the most useable power possible with your setup, instead of a generic (works pretty good) cam, then call Bob. No worries about reversion then either. Also, a lot of the Dart blocks can use a cam retainer plate on the front so you can use a step nose cam.

Heres a couple quotes from pslonaker from a 454 cam thread last year. This thread hes suggesting a very mild stock type cam, but last year he was suggesting a wild duration flat tappet cam for a 454. His cam recommendations are so far apart from each other, its ridiculous. Does he or doesn't he use comp cams marine sticks? This thread he says no way on the 731 cam, last year he says use it. Is this the guy you wanna take cam suggestions from?


What are the lobe centers on this cam. This is where your reversion will come from, but on another note, I have never seen a Comp Cam marine version not start to lay down at about 4600 rpm. I will not use them. You would be better off to use the Crane 731 cam...it doesnt lay down.

If you are running flat tappet cams, I would suggest that you run these Comp Cams... http://www.summitracing.com/parts/CCA-K11-244-4/ or http://www.summitracing.com/parts/CCA-11-244-4/ .

X3.......I should have mentioned my friend Bob Madara for your cam but I has caught up in a good laugh from the video.

"Magic room"

Definition of "magic"

1. the art of producing illusions as entertainment by the use of sleight of hand, deceptive devices, etc.; legerdemain; conjuring: to pull a rabbit out of a hat by magic.
2. the art of producing a desired effect or result through the use of incantation or various other techniques that presumably assure human control of supernatural agencies or the forces of nature.

Now it makes sense to me. It really is a magical shop full of illusions and entertainment

You should be able use either Gen cam with the right parts to install it.

The Crane #139011 is basically the same as the 168731 and made for MK IV and Gen 5's.

Can i ask why when a guy ask a simple question it turns out to be a three ring circus, call bob mandera at marine kinetics he will shoot you straight. Trust me dont be afraid to call some of the big rep engine builders as eddie young he is a hell of a guy, if you spend money or not hes not afraid to lead you in the right direction. And i know mild thunder does some awesome work look at his engines, just take it from me do your research or you will be disappointed.

Simple, when a pole smoker gets involved wether it be the original in this case or a want to be, misinformation comes spewing out like ralph on a heavy drinking night with the boys.

I do think the OP has been put in the right direction several times after the smoke from the magic room cleared.

It is very simple. There seems to be several on any web site that feel as if they should patrol each and every thread thinking that they are some sort of patrol officer for the site when in reality they are nothing but trouble makers as some in the Admin officeof OSO have stated. If you will notice, I do not go looking for them to cause an issue, but they always look for me. They know nothing about me, they have never done any business with me but yet they think they know everything about me or whatever it is that I do. I find it amusing and most of them cant say anything without stretching the truth all the way into next week as so many have pointed out to me. I could be standing next to any of them and they wouldnt have a clue. They remind me of nothing more than a bunch of little boys jealous as Hell over someone else, so they run their mouth and confirm the saying that it is better to be thought of a fool than open your mouth and confirm it. They dont know how to disagree normally without going out of their way to try to cause an issue. If you dont agree with them or if you say anything different from what they might say, then they jump all over you trying their best to belittle you or take away any credibility. Maybe I should publish some of the emails that I get from others concerning these clowns as to what they think of them but I wont say who they came from. It is funny tho because some of these people are friends with them and me. If only they knew. In short, these guys mind everyones business but their own.

The simple fact is, you post up nonsense, and to someone who truly doesn't know engines, might just take you up on that nonsense, because they simply do not know better.

Some of the guys here, who do know engines, will call you out on your nonsense. I am not a expert by any means, but I will NOT sit here and let you recommend a 218/224* flat tappet grind for a guy who has a potentially 500HP 454 with pretty decent parts, without saying anything. Im not being a "patrol officer" as you say, Im simply looking out for the person you are steering in the wrong direction. The cam you posted, even clearly states on comp cams website, as a skiboat cam, with a max rpm of 5000RPM. But you fired back when I questioned the use of that cam in this application, saying its MUCH larger than the stock cam...umm, stock in what?? Maybe the 330HP 454 with peanut port heads.

Contrary to what you may think Paul Slonaker, nobody on oso has it out for you. You bring it on yourself with your advice you give to others.

To get back on topic, the original poster has

454 Dart Block
Dart 308 Heads
Forged internals
9:2:1 compression.

This engine with the right camshaft, preferably a hydraulic roller, can make some nice power. In my opinion, 9:2:1 is right about where i'd wanna be for a pump gas iron headed pleasure boat marine setup.

well said patrol,i mean mild,i guess shooter puts me in that catagory also.

HURA! Why let another guy screw up because of bad advice.

I have been correcting SHOOTER, pslonaker aka as polesmoker since 2008 or so when he was posting his builds/disasters on teambajamarine. Does that make me a stalker?


Paul are you really building these engines on a daily basis as you stated in an earlier post? If so whose buying them? Why are they not here defending you? Have you updated your "magic Room"? If so lets see another video.

Hi Guys,
So it sounds like the 168731 is the cam if I'm going roller. Is there a good cam that you would recommend if I stay with flat tappet?

I will not suggest a cam thats what the experts (Bob Madara) do but even he will not talk to you about a flat tappet. Roller is the only option in my shop and all Bob will spec out for to many good reasons.

X2 on going roller. Not only do you get much better durability with a roller, you also get the performance benefit of getting that valve off the seat quickly.

yes go roller by all means, spend the money now or regret it later.

I went with a flat tappet because I was on my second rebuild in two years on BOTH motors. I wanted to go roller just didn't have the coin at the time. I have c Comp Cam XM-272-H it is a little small but builds power all the way up to 5400. I have the exact same setup as you BUT alittle more compression.

454 HP @ 5400

514 TQ @3800

I KNOW with a cam change and alittle work to my 308's I could make 500 EASY but my combo has been good to me so far!

This is the cam for anything normal and heavy. This cam just works. I've used it in 1/8 mile full bodied camaro (3600lb) drag cars. I've used it in a 23ft bow runner jet boat. I've used it in street cars. The secret: Large oval port heads with 2.19in and 1.88ex, 9 to 9 1/2 compression, install the cam straight-up on the cam gear as the cam has 4 degrees ground in. You do all of this and this cam will run circles around anything below 6000.