Sorry, another 383 cam choice question

[rt green]

i too live in Sioux Falls. small world huh?

[Q5XX29]

i too live in Sioux Falls. small world huh?

Yes, small world, indeed! So you have a green Charger R/T? Have we met before? I thought I knew most of the mopar folks in the area. Do you ever go down to the Hardee's cruise-in on Saturday nights?

[rt green]

no, i swapped it off for a 70 cuda. for better or worse. it was the third charger i had owned.      i knew everybody met down there but have never gone. also i've never met anyone from this site in person.  bruce

[Q5XX29]

no, i swapped it off for a 70 cuda. for better or worse. it was the third charger i had owned.      i knew everybody met down there but have never gone. also i've never met anyone from this site in person.  bruce

You should stop in sometime. If the weather is anywhere near decent, there will be a gathering. We need more mopars there! Would be nice to meet you.

Clint

[rt green]

will do. soon as i can get this bucket-o-bolts road ready.   now, back to the camshaft---------

[Q5XX29]

So, my Mopar mechanic (who gets all of the dirty jobs I don't want to tackle) installed the cam/lifters/springs/intake manifold, and broke in the Lunati VooDoo cam, but darned if one of those Johnson lifters wasn't defective. bad ticking, one lifter clearly won't stay pumped up, no matter when engine speed/oil pressure level. We have a new lifter coming in, but my concern is the cam- do you think that the cam lobe would have been adversely affected during the break-in? I know that Lunati  won't honor any warranty since I didn't use "their" lifters, but everybody on this forum speaks so highly of the Johnson/Topline lifters, I took the gamble.  Thank you for your thoughts.

[firefighter3931]

The cam will be fine....don't worry. Just break-in the replacement lifter with a 2000rpm for 25 minute cycle and let her rip ! 

That's the first time I've heard of a failure from Johnson. 


Ron

[Q5XX29]

The cam will be fine....don't worry. Just break-in the replacement lifter with a 2000rpm for 25 minute cycle and let her rip ! 

That's the first time I've heard of a failure from Johnson. 


Ron

Good to hear, thanks Ron. Yes, I figured that was pretty rare, but it definitely sounds like that is the problem.

[Q5XX29]

Update:

This has been very frustrating. Got the replacement lifter from Johnson/Topline- that took care of the ticking. I thought, "I must have bad luck. Everybody raves about the Johnson lifters, and here I get a batch with a bad one". But then things got worse. Took the car for a test drive, and thought hmmm, feels a bit stronger on the low end and midrange, maybe. Then hammered on it, and the thing started running horribly between 4,000 and 5,000 rpm, and then the engine just flatlined at about 5,000. Thought it felt/sounded like valve float, but kept trying to rule out other issues, since I thought it was unlikely that I have valvetrain issues, since I had all brand-new, matching components as recommended by Lunati (other than not using their Lunati lifters). Took the local Mopar guru friend of mine (who did the engine work) for a ride, and he also thought- wtf, seems like valve float. He looked further into it... did find that the Johnson lifters were longer for some reason than the lifters that came out, so we thought we had our smoking gun. He slapped on some adjustable rockers that he had laying around, set up everything correctly, and engine ran the same. Changed out orange MP spark box, tried two different distributors, and even pulled off the timing cover again to verify cam timing- all with no change. Doublechecked installed height of springs, and all was good. Started to wonder about a freaky cam ground incorrectly. THEN, found our smoking gun- the valve springs (the ones Lunati recommended for this application) are just too damn weak. We started researching the Lunati valvesprings (73815K6), and found that others have also found that they do not perform well, and cause early valve float.

So, I finally just said to heck with it, and ordered up some of the Edelbrock Performer RPM aluminum heads, all complete/assembled, with the 75 cc chambers, so that will get my compression up over a full point (hopefully to between 9.5 and 10:1, with the right head gasket), along with a set of PRW stainless steel 1.6 ratio roller rockers, and that should set all things right, and then some! Hopefully. Jeez, now I would have gone with a more aggressive cam. Oh well. The 1.6 RRs might help a little.

So, how do I approach this problem with Lunati? I hate to think of all of the expense I have incurred, tracking down this issue, when it turns out that it is their wimpy, recommended valvesprings. At the very least, they better reimburse me the cost of the parts I bought. Or maybe not. Customer service is usually disappointing, these days.

So, that is where I am currently at. Hope that the heads and roller rockers arrive mid-week, so might be able to take for a test drive next weekend.


Anyway, my heartfelt thanks again to Ron/Firefighter3931 for all of the help.

[BSB67]

How did you confirm that it was valve springs?

[Q5XX29]

How did you confirm that it was valve springs?

Spring pressure gauge. Barely 100 lbs closed, not tested open.

[Q5XX29]

Just remembered that this 383 just has the 516 heads (closed chambered), so I suppose my compression ratio won't change too much. I will go with the thinner steel head gaskets to help some. Or shouldn't those be used with the aluminum heads?

[BSB67]

How did you confirm that it was valve springs?

Spring pressure gauge. Barely 100 lbs closed, not tested open.

That will do it.

[c00nhunterjoe]

The 516s will be less of a difference then if they were 906s. Im personally not a big fan of steel shim on aluminium. Before you order any head gasket, i would pull a head off and measure your pistons, then do the math and select a head gasket to match the compression ratio needed based on the cam you are using.

[fizz]

I WOULD NOT USE THE PRW ROCKERS. I am sure the spring pressure on your build will be less than mine, but with the combination of a couple hrs run time and an hour of road testing, I pulled engine apart to replace the failing comp lifters, and found the rocker shafts were severly scoring on the bottom side of the rocker shafts. Harland sharps are like $200 something more.

[Q5XX29]

I WOULD NOT USE THE PRW ROCKERS. I am sure the spring pressure on your build will be less than mine, but with the combination of a couple hrs run time and an hour of road testing, I pulled engine apart to replace the failing comp lifters, and found the rocker shafts were severly scoring on the bottom side of the rocker shafts. Harland sharps are like $200 something more.

Well that is sure a bummer to hear- they have already shipped. I bought them because somebody else recommended them. Has anybody else had any trouble with the PRWs? They sure look like a decent-quality set. I bought them over these ones:  http://www.ebay.com/itm/Mopar-Chrysler-BB-383-440-1-6-Ratio-Aluminum-Roller-Rocker-Arms-Shafts-/171997436214

because I figured the quality of those eBay ones was probably low. Does anybody have any experience with either of these brands?

I was trying to save a few bucks where I could, since I just shelled out over $2200 for the edelbrock rpm heads! All for this lowly 383.

[fizz]

I don't know about those rockers. I have enough trouble even when I buy the good stuff.

[c00nhunterjoe]

I have never used the prws, my choice of a good midgrade rocker is these. http://m.summitracing.com/parts/cca-1621-16?seid=srese1&gclid=Cj0KEQjwrte4BRD-oYi3y5_AhZ4BEiQAzIFxnw1UVBVYP2inE9EnWF1vKa9s90aq9GoB5E7BgLagGP8aAvxb8P8HAQ

[XH29N0G]

Q5XX29, I have been following this thread because I have been interested in seeing things work out.  I think you will like the edelbrock heads.  I am using the Comp rockers at 1.5, but before that I used stamped steel rockers (with a hydraulic cam having lift in the neighborhood of 510/520 on a stroked 383) because those were what the engine was built with.  I know you sound set with others, but my understanding is that the stamped ones work quite well.  Orginally, I used the same lunati cam you have and edelbrock heads on the 383 and really liked it. 

[Q5XX29]

I have never used the prws, my choice of a good midgrade rocker is these. http://m.summitracing.com/parts/cca-1621-16?seid=srese1&gclid=Cj0KEQjwrte4BRD-oYi3y5_AhZ4BEiQAzIFxnw1UVBVYP2inE9EnWF1vKa9s90aq9GoB5E7BgLagGP8aAvxb8P8HAQ

Good to know, thank you. I was on the hunt for something available with a 1.6 ratio though.

[Q5XX29]

Q5XX29, I have been following this thread because I have been interested in seeing things work out.  I think you will like the edelbrock heads.  I am using the Comp rockers at 1.5, but before that I used stamped steel rockers (with a hydraulic cam having lift in the neighborhood of 510/520 on a stroked 383) because those were what the engine was built with.  I know you sound set with others, but my understanding is that the stamped ones work quite well.  Orginally, I used the same lunati cam you have and edelbrock heads on the 383 and really liked it. 

Thank you for the info. Good to hear. I would have no objection to the stamped stockers, but I wanted the adjustable capability because there was some initial concern with the problems I was having being due to the fact that the Johnson lifters we used being 1/10" taller than the lifters that came out. That turned out not to be the problem, but I still liked the idea of having more adjustability to compensate for these variances. Secondly, I really wanted to find a 1.6 ratio rocker option, because if I knew that I was going to end up getting better heads and bumping up the compression a bit, I would have gone with a bit bigger cam, and I thought this might be a small compromise (make the cam act slightly bigger).

Do you know what compression ratio you had on your 383 with the edelbrock heads and lunati cam, and what intake were you using? Do you recall what was your "redline" with that setup? My son and I are very anxious to see how different his 383 feels than it did before. Hoping it feels similar to my '70 Charger 383, which has mildly ported 906 heads, Comp Cams XE274 and 1.6 RRs, Performer RPM intake, headers, etc, but with 9.5:1 compression. We are very pleased with the way that little 383 runs (but no vacuum for the power brakes).

I am hoping that the parts are delivered by Wed/Thurs, and my friend can get things together by this weekend.   

Thanks again.

[XH29N0G]

Q5XX29, I have been following this thread because I have been interested in seeing things work out.  I think you will like the edelbrock heads.  I am using the Comp rockers at 1.5, but before that I used stamped steel rockers (with a hydraulic cam having lift in the neighborhood of 510/520 on a stroked 383) because those were what the engine was built with.  I know you sound set with others, but my understanding is that the stamped ones work quite well.  Orginally, I used the same lunati cam you have and edelbrock heads on the 383 and really liked it. 

Thank you for the info. Good to hear. I would have no objection to the stamped stockers, but I wanted the adjustable capability because there was some initial concern with the problems I was having being due to the fact that the Johnson lifters we used being 1/10" taller than the lifters that came out. That turned out not to be the problem, but I still liked the idea of having more adjustability to compensate for these variances. Secondly, I really wanted to find a 1.6 ratio rocker option, because if I knew that I was going to end up getting better heads and bumping up the compression a bit, I would have gone with a bit bigger cam, and I thought this might be a small compromise (make the cam act slightly bigger).

Do you know what compression ratio you had on your 383 with the edelbrock heads and lunati cam, and what intake were you using? Do you recall what was your "redline" with that setup? My son and I are very anxious to see how different his 383 feels than it did before. Hoping it feels similar to my '70 Charger 383, which has mildly ported 906 heads, Comp Cams XE274 and 1.6 RRs, Performer RPM intake, headers, etc, but with 9.5:1 compression. We are very pleased with the way that little 383 runs (but no vacuum for the power brakes).

I am hoping that the parts are delivered by Wed/Thurs, and my friend can get things together by this weekend.   

Thanks again.

I forgot about the lifter height issue and 1.6 ratio you were looking for until you mentioned it again. 

I don't know what the compression or redline were, but they could be worked out.  Originally, it was specified to have 9.5:1 compression and had 906 heads.  The gasket was thicker and the heads were the 84cc heads.  I also don't know what the redline was and did not have it on a dyno or at a track to check.  Sorry I don't have the information to pass along.

A little over a year after making the change, I decided to have the car restored and while that was being done made the decision to have the engine rebuilt. 

[Q5XX29]

My engine guy just informed me that the pistons in my 383 are 0.040 down in the hole, and surprisingly to me- are 0.030 overbore. I guess I have a 389! So, is this enough information to determine which head gasket to use (I assume I want the thinnest ones I can get, that are compatible with the aluminum heads)? And also what compression ratio would that give me, with my 75 cc chambered heads?

Thanks for the help, fellas!

[XH29N0G]

Try this.  http://www.wallaceracing.com/cr_test2.php

you should get 9.46 with the settings in the pic below.
You can adjust the gasket thickness etc... to find what you need.

I also made sure I was putting in the correct settings by calculating separately in excel.

[Q5XX29]

Try this.  http://www.wallaceracing.com/cr_test2.php

you should get 9.46 with the settings in the pic below.
You can adjust the gasket thickness etc... to find what you need.

I also made sure I was putting in the correct settings by calculating separately in excel.

Sweet- thanks!