Maca,

The 300 HP Magnum Crate was the stock truck cam and dual plane intake.
The 380 HP Magnum Crate was 230/234 ( i think) at .501 lift with a single plane intake M1. The lift was specific to the retainer to guide cushion. Both had the mopar HP spring. Stock long block was left alone.

The article you posted is 100 percent correct. Many have duplicated the combo. Since you are in Australila look at EQ heads since they are mad there and take your stock valves VT gear and flow better then Eddies. However, your heads are not the issue.

Stock Magnum truck motor / intake combo made 250 and when tuned properly that was a low estimate.

I have run both the airgap and the m1. Both are excellent. The M1 is the one in my avatar and currently on the rig. I would use the airgap for your combo.

The intake will make a big difference but something else is wrong.

What exactly are you using for PR length and rockers?

 

So what made the vibration go away?

 

Well sounds all good, and also what ever cam you had chosen is all done @ 5500rpm, for the "died very quickly".
Thought the reason for the engine removal was due to a vibration that has been incurable?? If it didnt vibrate on the dyno you answered your own question. the tq converter is wrong. (needing weights if i remember the original post correctly) Unless you didnt leave the flex plate on engine and they supplied the flex.

I would run the AirGap also for your combo as far as the intakes go...

 

Yeah, the thread kind of went astray, it happens but

 

Hey Pk1
For the PR length and rockers I am using the factory stock ones. I am running the cam mentioned in my other post. https://moparforums.com/forums/f62/3...539/#post81131
They did mention something about bad valve control. Do you think that 290HP is fair for my set up of the above cam with stock heads and stock bottom end with a 770cfm carby? Or does it seem a bit low?
Hey Bremereric
Your right, If the vibration was not on the dyno it must be somewhere else. They ran it with the weighted flexplate so the motor was balanced. Although it did not run for long as the dizzy seized. So i didn’t get a chance to go and see it myself. I have a feeling they were not fully concentrating on finding a vibration as they were trying to get the motor running nicely 1st. So I need to get a dizzy asap. Any suggestions on a good dizzy/coil etc as I need to improve my weak spark. They mentioned a msd al-2 as they want to program my timing curve?
Hey MrOldart2u
I might have to try the single plain as the duel plane manifold I have now is not very healthy. They said different cylinders are getting different amounts of air/fuel causing some to run hot and some to run cold. I am a bit stuck as I was told the single plain manifold are not great down low and work best from 3000rpm to 6000 rpm but on the other hand I don’t want to spend more money on buying a duel plane manifold when the one on the engine is not working properly. Although I was told apparently my manifold is a cheap copy of the edelbrock and known to have problems.http://www.pentastarparts.com.au/sun..._detail&p=3529
I am going down Monday morning to discuss what I want to do next. They want to change cams and ports heads etc etc but I am not sure I want to start with that expense. One thing for sure I need to get a dizzy and manifold.

 

Heck no. You are way low on power.

BINGO. Valve control!

The camshaft is cut on a small base circle to get the lift correct and still fit thru bearing openings. If you raise the nose of that cam to get more lift without making the base smaller it wont fit in the block. So the lobe is smaller that the factory one.

Meaning when you torque down the none adjustable rockers to the factory (21ft lbs, double check my memory on spec) you are not setting the .060 preload. So you are changing the duration of the cam since the valve is actuated later on the ramp when slack is taken up. This make heat and bad harmonics. Your cam is acting smaller...

What head gasket are you using? Specifically compressed thickness. Were the heads milled at all and if so how much? You need to measure for PR, get the right ones in there.

I disagree with their recommendation on porting and cam swap. You will still have issues. I disagree with the intake being bad unless they flowed it finding a defect. Just my ten cents.

You can swap to roller rockers using Holden gear which may be cheaper based on your location. A dizzy for sure and maybe the airgap. But PR length needs to be dialed in.

Stock PR is 6.904 - 6.912. With stock heads and gasket thickness most end up with 6.95 7.00 or 7.05 depending on the base circle.

PM me if you cant figure this out and I'll give you my phone number and walk you thru it. Your builder is probably leaning towards this too since he mentioned valve control.

 

Maca, If you are wanting to stay dual plane you may get by with a good porting job with the intake you have but you have doubts and want to change it to the single plane design the afformention intake would work fine... I am not for sure it wil help much on top end power tho due to what the camshaft selection actually is. It maybe the real culprit in that case, and but the dual plane intakes are getting close to being all in also in the 5500-6200 prm range with no massaging also. I dug around on the site you posted and the selections for some stuff is rather limited, and the camshaft selection require a call to Crower Cams AU (good cam company btw, or here in the states they are). BUT if you are going to go to the single plane intake the one listed in the other post would work well.


Also you stated that they ran it with the weighted flex plate, was that YOUR flex or theirs? Stating its the weighted one suggests that its the "normal" Magnum styled flex plate, with aftermarket ones looking like they have a large piece "missing". So you may want to compare YOURS with THEIRS, and if they are different have YOURS matched to the same balance as theirs..

The M1 intake part no. IS a little illusive, I to am having a problem finding it, but I am d/l the Mopar Performance catalog as i type this... (havent had luck findint the correct 'part' of catalog to d/l so I am just doing the whole cat.) The Air Gap intake for Mag motors is part no. 7577 from Edelbrock site.

D/L complete, Mopar Performance Part no for the illusive intake has been found, and it is P5007380AB . Listed as "Intake Manifold, Aluminum, Single Plane, Four Barrel, Carburetor, 5.2L/5.9L Truck Magnum,Jeep Engines,Magnum Crate Engines" It looks to be dual drilled for either style of carb. Hope this helps....

 

MrOldart2u Thanks for finding those part numbers. I will research them to see if I can find the manifolds in Australia
Hey PK1
Thanks for the help too.
I think i am getting what you are saying. So with a performance cam, the lobe opens the valve higher and longer. They achieve this by not making the high point on the cam lobe higher as it will not fit through the cam bearings but they achieve this buy grinding the low part of the cam lower.
Would this then make my push rods looser and or too short? Meaning the valves are not opening enough.
When i was there they got the number 1 cylinder and loosened the rocker. They then softly tightened it until they couldn’t twist the push rod with their fingers anymore. They then torqued the rocker down and it took 1 and 1/4 full turns. They said it should only have taken about 1/4 of a turn to torque down. This must be the preload problem.
So i am guessing the adjustable roller rockers will fix this or will i need to get different push rods too.
Or am i way off

 

Not to disregard my previous post but PK1 is right, I was in the middle of my "hunting and searching" as ya'll were posting...lol

 

Maca you got it!!! And those are NOT adjustable rockers!!! They are adjusting them WRONG cause they aren't adjustable.

The PR are too small and not opening the valve fully or at the correct timing.

You can get a longer PR thru measuring or switch to adjustable VT. Adjustable will still need new PR to set geometry right. They will make more power.

Depends on your budget.

When I get home I will send you VT tightening specs for the magnum. Sorry, dont have them handy.

 

Thanks, Will the tightening specs help me work out the pushrod length or will the shop have to measure that for me? Also if there is a set of holden or any adjustable vt you can recomend i would appreciate it.
cheers Greg

 

Spec for tightening is 22 ft lbs NOT 21.. Sorry, Im getting old

Option 1

They will have to measure but its not hard and will be very economical. They use an adjustable push rod and mock up the vt. Since it is a pedestal type mount the rocker has a fixed distance from the head. They are a really strong set up.

Option 2
If you want to make it adjustable you need the individual components from comp cams 1425 kit.

This has
5/16 studs to 3/8 24 count rocker studs
holden 1.6 single roller rockers
guide plates
6.8 pushrods
and lash nuts

My recommendation is NOT to buy it like this as a kit. Call them and get the part numbers cause you don't need the push rods. Youll need to measure for PR. The kit is set up for stock cam. Get the parts your self.

You can use any gen 1 5.7L 350CI holden rocker, the arp 5/16 to 3/8 stud conversion and guide plates. Buy the lash nut that goes with your rocker. Get an adjustable pushrod. Measure for length and run it.

Optiton 3

Harland Sharp: Rocker conversion. They are expensive but geometry wise they are dead nuts accurate pieces. They make a lot of products for other companies. These rollers are for our motors and heads. I currently run these on a 400 HP + small block with a 400 lb rate valve spring. At 10,000 miles they had zero signs of wear. Its a family business and pretty sure one of the sons works the tech line. Service was excellent.

My opinion since its on the dyno is use the current rockers, use any manufacturers oil thru PR 5/16 that fits and get your pull and tuning data. Save the money for an airgap manifold or new rear tires

Do NOT discount retorqing the rockers to spec and trying what you have sizewise. If they were all lose it will run like crap too. Im hoping this is your issue.

Good Luck Mate!

 

hey PK1
So with adjustable push rods, are they just used to find the correct push rod length so i know what length to install or can i run the motor with the adjustable ones in it.
I have a set or roller rockers that came with my car. They are to suit a Ford Windsor 1976 on. The cam installers said the hole centeres were slightly out and i couldnt use them. Bugger
cheers

 

Simply a tool to allow you to dial in height for your correct application. You can tape the adjustable one and send it or carry it to your manufacturer. Or measure it yourself and order off the shelf parts. You dont run them in the motor.

 

No matter what you use Stock or adjustable rockers You need the correct length push rods.... PK1 shows an adjustable one

 

Maca, adjustable rockers you can run in the engine, the adj pushrod is for finding the length of pushrod you need to order/or have made, and NOT to use in a running engine.. Hope this clears the murky waters... The adj you have that are for the windsor ford i doubt will work... try and swap them out to your builder for either a set for the mopar, or a lil and the right length pushrods for your motor...

 

Actually...............there are adjustable pushrods that are/ were designed for use in a running engine.

But you don't have to BUY anything. IF you know for sure that the ones you have are wrong, just sacrifice one for length testing. Cut it somewhere in the middle, cut a piece out of it, and insert a length of threaded rod with 4 nuts so you can lock them. Alternatively, cut off a bolt, and braze/ weld it into one half, and just use two nuts on the threads.

I would check an exhaust and intake at all "4 corners" of the engine, and unless the heads/ deck is REALLY off badly, you should get an average reading. Just measure the thing and send to your choice of manufacturer.

I believe the Mopar Performance cat. lists a "cut to length" kit of pushrods, you can make your own.

 

Is this correct=The information I will need to supply the dyno shop to install the correct push rods is-
My spring Installed Height/Pressure for the Hughes hug1110 spring : 1.660"--120#
Torque setting for rocker bolts is 22 ft lbs
Will I need to give them a pre/load number? How do i work out the load of the new springs
Or any other info
cheers

 

Maca,

The info on adjustable PR above is spot on. All good info.

440Roadruneer stated that they make a cut to fit PR and they can be used on motors. He is correct. He is dating himself but I remember those too And the 4 corner method is a excellent way to do a build. A good builders live in the details. Unless I did the deck and heads I do it the exact same way.

I don't want to confuse you but you can NOT use an adjustable PR on motor for anything other than mock up. The magnum motor oils the head and valve train thru the pushrod center via the lifter assembly. Different from the LA style. So there is no escaping new pushrods. You can cut and paste a PR to get new height needed in mock up.

For those following this post couple things to keep in mind. The Magnum Motor was not a production item or was very limited production run in Australia. So MACA and his dyno guys are cutting their teeth on this one. Bit of a learning curve but they'll get it dialed in.

You do not need SPRING info for any part of this process. I can do the math for you if you want it for your records? What was final lift on both intake and exhaust? I have the spring data here.

All they need to do is set up a non adjustable valve train just like any hydraulic non roller system. Same as a basic Chevy set up but with magnum preload of .060

Couple things they will need to know if this is new to them:

-The Magnum PR have a length of 6.9. I posted exact specs above and those are the acceptable tolerances.

-Yes, torque spec for rocker bolt is 22 ft lbs.

-The pre load for a magnum lifter is .060. NOT .020!

So even if they were doing adjustable rockers and using they 1/4 turn method ( which is wrong for this application ). 1/4 turn on a standard 3/8 24 thread bolt nets as follows:
1/4 turn .010
1/2 turn .020
3/4 turn .030
1 turn .040
1 1/4 turn .050
1.5 turn .060

They were using a light pre load for a Chevy when they cranked that 1/4 turn. Most chevys need a pre load of .20 However some builder have their preferences on what works best. They are in the big leagues now since the have a MOPAR in there. It would have taken 1.5 turns not 1/4 turn.

Dodge specs pre load on the Magnum lifter at .060. I have found NO issues with .040 to .060. No noise or oiling issues. No wear.

Why did I tell you this? You will need to know it if you go to a roller rocker conversion.

The info above is NOT applicable to the stock valve train. Just keep it for future.

If they cant set it up or need help, PM me when you try this and if I'm free I'll talk you guys thru it..

OR

I have a cam core from your same short block here and will measure base circle. If you pull your cam slightly and measure base circle on two lobes and get me your part number for your head gasket, I will do the math for you and spec you a pushrod.

 

Thanks for the info PK1
How come counting the turns to check pre-load only works with roller rockers and not my rockers.
cheers Maca

 

The current Magnum Rocker is mounted to a pedestal. Fulcrum point is fixed distance from head. The article below is relative the magnum system as the pedestal system is the same. However the magnum rockers are VERY strong. They still sell new for over 100 bucks in the states.



http://www.mustang50magazine.com/tec...rms/index.html

 

Thanks PK1
I went down to the dyno shop today and asked them to measure for correct push rods length. So that is my next step.
They are happy to do that but they are determined to port the heads as they have recommended it several times(intake only). They reckon it will make a huge difference and said if i want to upgrade the cam for more power later it will be able to handle the extra power. I am happy to port them while it is in there shop if this is a reasonable request and worth doing.
Is it possible as the magnum is a low compression motor to install a thinner head gasket to increase compression and sneak out a bit more power? The LA gaskets look like they might fit.
cheers Maca

 

Magnum isn't low compression motor.

Yes, LA gaskets will work. Water passages are the same. When you look at compressed thickness make sure you are comparing VOLUME so you are going in the right direction.

My ten cents on porting?

Set PR length, tune the carb, get your numbers. If you missed your mark and you think that magic number is in the head flow then sure. I would never port a non running motor. And you have a vibration which still may be present when installed. If they stand by their head work they will want you to have a good pull and then compare it to the ported heads.

Yes, the intake side needs the work to keep a decent ration but consider this and a knowledgeable Mopar guy ( hopefully your builder) will tell you this.

Upping the magnum casting on the intake will yield a max 230cfm at .500. You CAN gain velocity past .55 and hold that 230 cfm up to .60. BUT to use a cam in that range you need to drop the spring seat, machine the step, drop the guide. Since the heads are weak in the castings this is not a wise investment. This work is expensive. They will crack.

Especially when Australian made EQ heads flow 220 plus at .0500 out of the box and use all stock valve hardware. These heads have a very heavy casting and with a 2.02 valve will get to 250cfm with mild cleaning.

Also, and dont take this the wrong way please, but are these the guys that did 1/4 turn on a non adjustable valve train? Or you guys just rent the cell and tune by the hour?

 

Hey PK1
Thanks for that info. This has been a great learning curve for me.

Yes these are the same guys as before. I have stayed with them as they did the engine balancing and once we get the motor running again if the vibration turns out to be a balance problem then they can fix it.
I think your right about they dont know mopar engines as they are well respected in the race scene in Australia but they admitted today that this was the 1st magnum they have worked on. I think they are chevy engine lovers.
I just need to get a dizzy now and we can run it again. The problem in Australia is engine parts are very expensive. A USA $315 manifold is $550 here and a msd is $635
http://www.pentastarparts.com.au/sun..._detail&p=2369
We have a couple of cheaper brands but i have run them and they didnt last. I can order from the USA as long as i am not in a hurry for parts. With my set up and a good ignition what HP do you thing i should be reaching. 330?
I will let you know how i go. cheers maca

 

Hi all
Just an update on my motor. It is being put back together with the correct push rod length at the moment. I have ordered some roller lifters and gaskets from the US so they will take about 5 days to get here. When its back together i will post an update.
cheers Maca

 

Hi all
Well I went to the dyno shop today, my motor was all back together ready to go but they were just waiting for the push rods to arrive. Unfortunately at 5am tomorrow morning I go overseas for a 3 week holiday so I will have to run it when I get back. I will update my post when I get back.
One thing I have noticed that may help me to find the vibration is today I took the converter in to the shop to measure the nose of the converter and the back of the crank to see if they fit nicely. On the throat of the converter there are already wear marks. The marks look like the seal or something has been rubbing. The marks are not even around the shaft. They run slightly up and down the shaft as you rotate the converter. The dyno shop said that if the block had been heavily line board then the crank and trans shaft may not be aligning up. I will have to check this when I get back. I guess I will have to bolt up the trans without the converter and run a straight edge down the trans shaft to check if they line up. I will post a pic when i get back. Cant wait go go on holiday
Cheers maca

 

im using the edelbrock air gap on my 318 and my throttle response and general performance is awsome and my CHAMPION sparks are so mmt deposit even its uncanny w 650 avs carb the manifold has a divided plenum got mine at summit im sure they have one for your magnum

 

jst for a quick note i had purchased brand new tork converter and the center hub was welded on slightly off the absolute 90 degrees which caused sever vibration and it made scares in the bell housing from contact also on the hub the seal scraped

 

You cannot do this. If you even suspect bellhousing misalignment (center of crank to center of transmission) you MUST check it with an empty transmission case, preferably the one you intend to run.

However, there might be a way to cheat. If you pull the front pump, and can round someone up with delicate hands, you might be able to "rig" a dial indicator on either the flex plate or crank flange with no converter installed.

You'll have to indicate two ways, but the most important is radial. If you could rig the indicator mount to the crank, rig a mirror so you can get up in there an observe, and indicate on the machined recess for the front pump, that should give you a VERY good idea of alignment.

 

Thanks guys. I will look deaper into it when i get back. My main concern is to get my motor back from the dyno shop and then I will post a couple of pics of the marks on the converter.
This was me trying to cross the road today in Vietnam. I felt like a duck taking its family across a highway.