4.6L Stroker, Help me build it please!

[jeepinwi]

If I were to build another stroker, I would go with a Comp Cam 68-231-4 or buck up for a Hesco RVOB6 cam.

 

[I dig AU]

I don't usally post on this forum because I have a ZJ, but since your talking about a 4.0 stroker, I'll add my .02. I'm currently building one too.

My machinist told me not to worry about my Crane cam. Everyone is having problems. He said he''s had 4 different Ford engines have cams go flat. He added "that's unheard of". It's an oil issue. That said, it would be foolish to not have the machine shop CHECK those seat and fully open pressures. Just for giggles, I had him check my Mopar springs out.

seat pressure (closed) 120 lbs
open at .500 lift (close enough to my .484 lift on the 905 cam) 260-270 lbs (right about what Crane recomends)

He added that almost all springs lose about 10% of their seat pressure in the first 15 minuites a motor is run, then settle in. That brings down that 120 lbs seat pressure to right where Crane recomends for the 901/905 cam, 107-108 lbs.

In addition, most performance cam companys now recommend you use a breakin additive for those first 20-30 min. Crane sells it, so does Comp Cams. I haven't checked anybody else. I've heard that the GM EOS additve is very good as well. And I believe they all recomend AGAINST synthetic oils in flat tappet motors, but if you must, wait until completely broken in. I have an opinion, and it's just an opinion. I think this is what happened to Dino's. I'm not looking for a fight. It's just my opinion. A flat tappet MUST spin or it'll eat the cam. I think synthetics are just to slick with performance springs. But they seem ok with stock motors.

your mileage may vary...

 

[XJoshua]

I think Im going to give CraneCams a call and see what their policy is, because they are infact the cheaper cam. If they will replace their cam if it goes flat, and the lifters that go bad, Id be willing to go with them. Im thinking about doing what Hesco does with their alunimum head which enlarges the oil gullies so you can retrieve a lifter without removing the head.

Any ideas on this, if I should, or should not.

 

[TRCM]

Can I get my valve tips filled down in order to make them flush with the retainer? See post #79 for picture.

Simply, I ask why ????

No engine I have built has had them flush like it seems you want, and I have been many engines, the latest made 1146 hp & 906 ft lbs on the dyno (single 4 bbl, no n20 or boost). The rocker roller or tip rides on the end of the valve stem anyway, not the retainer.

Now, If you need to do this to fit the rocker arm, then you should get different rockers instead. If you file the valve stem end down flush, then it will weaken the stem tip, and it could snap off.

 

[XJoshua]

But TRCM have you seen how much stem shows. I plan on running good ole P.O.S. stamped steel rockers until I can upgrade to some YellaTerra 1.6s. If I do use them without shaving the stem wouldnt I have to add alot of spacers to keep them from having a odd angle.

 

[I dig AU]

Can I get my valve tips filled down in order to make them flush with the retainer? See post #79 for picture.

Simply, I ask why ????

No engine I have built has had them flush like it seems you want, and I have been many engines, the latest made 1146 hp & 906 ft lbs on the dyno (single 4 bbl, no n20 or boost). The rocker roller or tip rides on the end of the valve stem anyway, not the retainer.

Now, If you need to do this to fit the rocker arm, then you should get different rockers instead. If you file the valve stem end down flush, then it will weaken the stem tip, and it could snap off.

.[/QUOTE]

I agree! What's important:

installed height, function of what the spring manufactuer recomends to get proper seat and open pressures. Can be changed by using shims or machining the seat pockets, also to a degree by how deep the valve job is cut. There are also valve locks out there that change the installed height by where the grove is cut in them. They come in + or - .050. Grinding down tips is ill advised. Most valve tips are hardend. Maybe stainless valves are different, but still best left to your machine shop.

difference in length between the valves you bought (Chevy) and the stock valves. This will affect the valve train geometry.

Why you chose Chevy valves and springs, I don't understand. There are Mopar parts out there that match right up! Maybe you got a deal. Did you research the valve lengths? How about if the Chevy springs fit the spring seats, or does the head need to be machined for them to fit. Maybe you'll be just fine, but these things should be checked before purchase.

Trying to open up the stock iron head so you can remove lifters... I bet you hit a water jacket. The aluminum head is a custom casting.

Good luck with your build!

 

[Dr. Dyno]

And I believe they all recomend AGAINST synthetic oils in flat tappet motors, but if you must, wait until completely broken in. I have an opinion, and it's just an opinion. I think this is what happened to Dino's.

I used Castrol dino oil for the first 3000 miles so what you've said doesn't apply to me. I did use synthetic thereafter but it still took another 30000 miles or so for just one cam lobe (no.6 intake) to wear flat. Even then, I don't think the oil was the issue 'cause the problem started first with a collapsed (but not worn) no.6 exhaust lifter.

 

[I dig AU]

I used Castrol dino oil for the first 3000 miles so what you've said doesn't apply to me. I did use synthetic thereafter but it still took another 30000 miles or so for just one cam lobe (no.6 intake) to wear flat. Even then, I don't think the oil was the issue 'cause the problem started first with a collapsed (but not worn) no.6 exhaust lifter.

Dino, I have TONS of RESPECT for you! But if one of those tappets stops spinning anytime in it's life, bye bye cam. Even a little piece of grit getting by the filter could cause it. As I said previously, I think (my opinion only) it's a bad idea to run a pure synthetic in any flat tappet motor with higher spring pressures.

I do agree with you on the collapsed lifter, a quality issue that could happen to anyone. Not good if they have a pattern of failures.

Bowing as I back away...

 

[XJoshua]

I dig AU-
Dino told me about the chevy valves, and valve springs. His word is golden to me as Im sure it is to everyone else on this forum. I have yet to measure the valve height differences between the 350 and the 4.0. The chevy springs are 1/64" longer, but this might be because the chevy springs have not been broken in, and the 4.0 springs have been.

I do plan on machining the head, because the valve stems need to be reemed inorder to properly fit. I did get a deal on all my parts for the head, so it wasnt something I was going to pass up.

 

[I dig AU]

I dig AU-
Dino told me about the chevy valves, and valve springs. His word is golden to me as Im sure it is to everyone else on this forum.

And it's true. If he says they'll fit, then I'm sure they will. He does know his parts! Where would we all be without his web site!

But, that said, it's always a good idea to have the shop check for clearences. Tell them how much lift your cam will run. Then you know it fits because the shop checked it out on YOUR head. Enjoy, your motor ought to scream!

 

[ChevelleSSLS6]

get the valves backcut for more flow could be added.

 

[XJoshua]

Backcutting valves is the doing of what? Is it really going to be worth it after larger valves, good springs, port n polish, 01 intake, pacesetters, and 3 angle valve grind? Using a simple HP 1/4mile calculator if I make 290HP at the crank Ill run a 12.5 on a 1/4Mile. Im sure this is way off and not really my goal, but if backcutting shaves some seconds off thatll always be welcomed.

EDIT: Nevermind kinda found out. Seems like its just changing the valve angles to 25-30*. Here's a linky I found. http://www.chicagolandmopar.com/techtips/backcutvalves.asp

 

[tealcherokee]

my simple hp-1/4 calculator that factors in weight, wind resisntance, and everything says my expected 390 BHP will bairly run me 12.8, so dont get your hopes up

 

[XJoshua]

I have no hopes, and no plans to be a track monkey, because track monkeyism leads to being a ricer

My only hope is that the engine cranks over within five days after being installed.

 

[Flash]

Back cuting the valve takes the sharp edge off from the 45* suffice of the valve.(kind like a (2) angle valve job with a (3) angle job on the head!

If your trying to get every HP out of it,.....its worth your time. if your going to put a cam in that is close to stock you won't find any HP by doing this.

With you running 2.02/160 valve in the head, you had better put a big cam in or it will probably port stall!

Hi rpm is were these mod show there power.


Flash.

 

[Dr. Dyno]

Dino, I have TONS of RESPECT for you! But if one of those tappets stops spinning anytime in it's life, bye bye cam. Even a little piece of grit getting by the filter could cause it. As I said previously, I think (my opinion only) it's a bad idea to run a pure synthetic in any flat tappet motor with higher spring pressures.

I do agree with you on the collapsed lifter, a quality issue that could happen to anyone. Not good if they have a pattern of failures.

Bowing as I back away...

Hehe, it could have been the spring from the collapsed no.6 exhaust lifter that got lodged in the neighboring lifter bore and stopped the no.6 intake lifter from spinning, taking out the no.6 intake cam lobe in the process.
I still had 11 perfectly good cam lobes left so I still have a hard time believing using Mobil 1 could have caused the cam/lifter failure.

 

[I dig AU]

Hehe, it could have been the spring from the collapsed no.6 exhaust lifter that got lodged in the neighboring lifter bore and stopped the no.6 intake lifter from spinning, taking out the no.6 intake cam lobe in the process.
I still had 11 perfectly good cam lobes left so I still have a hard time believing using Mobil 1 could have caused the cam/lifter failure.

And there ya go. Just maybe. Obviously I don't work for Crane, but after a long talk with my machinist, I just don't believe it's ALL CRANE'S FAULT. There are exceptions. Mr. Shoeboy really got the shaft with the wrong parts first time around. But if the shop had check clearences for him (knowing his cam lift), it should have been caught right there. That's just a plain shame. Then cam gear / oil pressure issues (which are documented now on the web... search) and he's got to rebuild his bottom end, sad. The bottom line from my point of view, I don't think it's safe to take anybodies word for it. Things need to be checked (read measured) to be sure of fit. Then you know it's right on YOUR head. I'm going to use my Crane cam (and lifters), and everything will be checked. I'm building mine with a standard oil pump. We'll see if I can get away with it. Now, I just need more money to finish it. Sucks

Wishing the best on everyones stroker build!

 

[XJoshua]

Well will the 2.02/1.60 valve with Z28 Springs rated to work with something slightly more then a 260/272 cam show improvement with backcut valves?

Im going for budget and so far I should be able to end up with a grand total of building costs at $1800. I feel that is pretty budget for springing for the larger valves. Should I go for a larger cam and get a aftermarket vacumm canister? Remember this is a daily driver, and weekend pre-runner/crawler.

 

[Flash]

I'm not claiming that i am the "Know" of all this. Just trying to get all the info i can before i dive into one of these stroker and sharing what i have learned a long the way.
when i would plug in the numbers(Dyno Simulator) with a bigger valve then stock(1.91/1.50) the torq at low rpm(1500 rpm) would be down a fue Foot Pound of torq.
----------------------------------------------------------------------
K let me change my mind!

just went and ran a "stroker" Dyno Sim with my favorite cam...so fare(68-231-4) with the bigger valve installed and every this the same as before(head pocket ported) the 1500 RPM, HP and Torq DID NOT change but the max HP was up by 10 and the max torq was only a couple more but was at 500 more rpm!!!!!

I'm going to have to do a lot more playing with this now but larger valve will not hurt..........
larger ports will destroy torq........I have dun this in real life.

K finest rambling, you can wake up! :laugh:

 

[Frank Z]

Which program are you using? I can't seem to find a shareware dyno simulator that allows me to plug in all the variables.