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Re: Why do only Mopars experience "cap walk"??? [Re: CRE2004] #13699
12/14/04 02:18 AM 12/14/04 02:18 AM

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i don't mean to demean girdles. i'd enjoy hearing more about the broken cranks and what type and brand they were. as it's been said a million times, the factory blocks were just never engineered to withstand that type of HP. don't take this the wrong way because 900+ HP is nothing to sneer at if it continues to work, but do you feel it would work as well in a heavy car situation as well as it does in a light chassis like a dragster.
i think there are pro's and con's to both steel and aluminum caps. we've seen a number of guys break the stock caps with what i would consider fairly mild motors at 650 or so HP. has that motor your referring to been torn down yet to see the effectiveness at reducing walk and or bounce of the caps?
people seem to forget that better higher tensile strength studs are available to help with the obvious issues. there is also enough material to go to a larger stud which does help. i'm sure harmonics plays a huge roll in a lot of block failures. unfortunately many machine shops just don't have the ability to dowel the mains either. it truely is a worthwhile investment if your engine will be on the edge of failure without it.
i'll be doing a mild RB 511 combo for my own car this year if you want to donate a girdle for testing , LOL. it likely won't be much over 700HP though. thats about all i'd want in a street pumpgas combo.
on another note, i applaud everyone thats trying to make improvements for the parts most have available to use.
and lastly, one of the problems that people just refuse to belive for the most part is that soft chinese forgings actually aggravate the cap bounce issue due to all the flexing that goes on. it causes a multitude of other problems as well. of course if your building a mild combo i guess it shouldn't be much of an issue.

Re: Why do only Mopars experience "cap walk"??? [Re: Ramcharger] #13700
12/14/04 02:39 AM 12/14/04 02:39 AM
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North Sweden
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Quote:

RT, what kind of dowels did you use and where are they available?





I didnīt do the installation and I didnīt even own the block at the time, but it was Jari Konola here in Sweden who made both the new crossbolts and installed the dowels. Sorry for not answering you quicker but itīs 6 hours time diff. to the eastcoast for me, so I have been sleeping.

Re: Why do only Mopars experience "cap walk"??? #13701
12/14/04 02:45 AM 12/14/04 02:45 AM
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Illinois
CRE2004 Offline
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Quote:

don't take this the wrong way because 900+ HP is nothing to sneer at if it continues to work, but do you feel it would work as well in a heavy car situation as well as it does in a light chassis like a dragster.


Not at all, there's a major difference in stresses implied by a heavier car, and I think that's in part why he's been able to get away with using stock caps at that HP level.
Edit: one thing that is yet to be determined; is the stud girdle easily handling the 935hp stock cap combo in a light dragster or is it at the ragged edge of its limits. I guess we'll determine that once I find a 935hp stock main cap engine in a 3800# drag car to test with.
Quote:


has that motor your referring to been torn down yet to see the effectiveness at reducing walk and or bounce of the caps?


Not yet that I'm aware of , but I'll inquire and post back with pics if I can get 'em.
Quote:


i'll be doing a mild RB 511 combo for my own car this year if you want to donate a girdle for testing , LOL. it likely won't be much over 700HP though. thats about all i'd want in a street pumpgas combo.


I think you'd be a very impartial test subject maybe I'll take you up on that
Quote:

people just refuse to belive for the most part is that soft chinese forgings actually aggravate the cap bounce issue due to all the flexing that goes on. it causes a multitude of other problems as well.


They were Exxxx cranks that broke..
Mike

Last edited by CRE2004; 12/14/04 08:39 AM.
Re: Why do only Mopars experience "cap walk"??? [Re: CRE2004] #13702
12/14/04 05:29 AM 12/14/04 05:29 AM

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Quote:

Dan's system (pictured below) is a four bolt main cap conversion requiring some fairly involved machining. ..... He lists his setup as withstanding 1500hp and I'm not in a position to doubt him.



Dan has one customer with a Blown Alcohol Tractor pulling rig that is exceeding 2500HP on one of his 4-Bolt conversions. Would not have believed it if I hadn't seen it with my own eyes.

Re: Why do only Mopars experience "cap walk"??? #13703
12/14/04 07:41 AM 12/14/04 07:41 AM
Joined: Jun 2003
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Lot's of great reading here...even if it does make my hair stand up...my 496 is a lo deck with Muscle Motors Aluminum caps, ARP stud kit, eagle crank and rods, Ross pistons, ATI Super Damper and a partial fill on the block...sees 6800 on the shift chip...based on the ET/WT ratio figure the car is making close to 800 hp...only made about 100 passes last year ...so...I can only hope I'm "controlling" my cap bounce...what do you think?

1968 Plymouth GTX
1974 Dodge P/U Long Bed Stepside 318
2019 Ram 2500 6.4, auto, 4WD
Re: Why do only Mopars experience "cap walk"??? [Re: CRE2004] #13704
12/14/04 08:10 AM 12/14/04 08:10 AM

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Quote:

i'll be doing a mild RB 511 combo for my own car this year if you want to donate a girdle for testing , LOL. it likely won't be much over 700HP though. thats about all i'd want in a street pumpgas combo.


Quote:

I think you'd be a very impartial test subject maybe I'll take you up on that



oh well, i guess with all the hammers and laughing guys that means no. i set myself up that for that one real well.
Re: Why do only Mopars experience "cap walk"??? #13705
12/14/04 08:36 AM 12/14/04 08:36 AM
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Illinois
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Quote:

Quote:

i'll be doing a mild RB 511 combo for my own car this year if you want to donate a girdle for testing , LOL. it likely won't be much over 700HP though. thats about all i'd want in a street pumpgas combo.


Quote:

I think you'd be a very impartial test subject maybe I'll take you up on that



oh well, i guess with all the hammers and laughing guys that means no. i set myself up that for that one real well.



Once you get that 511 underway, have your people contact my people and we'll work something out .......'looking for the shady mobster emoticon but not finding it'...

Re: Why do only Mopars experience "cap walk"??? [Re: Ramcharger] #13706
12/14/04 08:40 PM 12/14/04 08:40 PM
Joined: Aug 2004
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SE MI
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IMO a contributing factor is the poor machining done by Crysler's production equipment. The blocks I've inspected and machined show the mounting surface for the main cap to be out of flat by .0015". This is one each cap surface, not the total condition. This would cause the main cap to contact the block only on the 'crests' of the surface reducing the compression strength by limited contact. It would also allow more motion in the cap than if there were full contact. Motion of the cap will be transferred to the main bulkhead through the cap bolts resulting in vibration that will eventually cause cracking and failure of the main bulkheads. My solution would be to machine the mounting surface and caps flat and use a girdle to eliminate or at least reduce cap motion.

Re: Why do only Mopars experience "cap walk"??? [Re: Duster499] #13707
12/14/04 11:57 PM 12/14/04 11:57 PM
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Carstairs, Alberta, Canada
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I have yet to see this "cap walk" first hand.
I'm not doubting it, or anything like that...

I'm curious...
At what horse power level does it start to become evident?

Re: Why do only Mopars experience "cap walk"??? [Re: dave571] #13708
12/15/04 07:26 AM 12/15/04 07:26 AM
Joined: Jun 2003
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Weatherford, Texas
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I didn't realize what I was looking at the first time I saw it and that was during the rebuild of a .030 over, stock crank, stock rod engine that was probably making between 500 and 600 hp...it wasn't until I had the engine back in the car that a buddy at the track ask if my main caps were walking...???? ...oh well they were still bouncing when I took it apart about 500 passes later... ...after that I started making more horsepower, added studs...then aluminum caps and studs...still bouncing/walking caps... I guess it's just something to live with until I install a girdle, cross bolt it of buy an after market block...

1968 Plymouth GTX
1974 Dodge P/U Long Bed Stepside 318
2019 Ram 2500 6.4, auto, 4WD
Re: Why do only Mopars experience "cap walk"??? [Re: RapidusMaximus] #13709
12/19/04 11:35 PM 12/19/04 11:35 PM

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At what Hp level does this start? Is it RPM related too or does torque play a part too?

Re: Why do only Mopars experience "cap walk"??? #13710
12/21/04 02:44 PM 12/21/04 02:44 PM
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my experiance with this is i was at the crank dyno 648 hp/595 torque with 300 shot nos in a 3400 lbs 69 tubbed cuda with a stock crank and caps. it ran great and held together for about 200 runs but it finally gave last summer. and no im had no idea about cap walk or anything like that i was told i was on the edge everytime i hit the nos but go or blow is my moto. this time im getting alluminum caps and i have the cre stud girdle. so this summer i will make more hp and tell your what i find out. if it works great if it didnt i will let you know.

Re: Why do only Mopars experience "cap walk"??? [Re: CRE2004] #13711
12/23/04 01:17 PM 12/23/04 01:17 PM
Joined: Nov 2003
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Illinois
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We just heard from our customer who's running our main stud girdle with the 935hp low deck with stock caps in a dragster. He pulled the lower end apart and stated that the bearings look as if they only had one run on them and zero signs of cap walk present. Some of Jerry's comments were that the vibration level was extremely low and the dragster was much 'smoother' to run. They turned this engine all season on one set of bearings at 8100rpm. I'm glad we were able to help them out and it looks as though we'll be machining them a new block for next season...

Re: Why do only Mopars experience "cap walk"??? [Re: Ramcharger] #13712
12/24/04 12:27 AM 12/24/04 12:27 AM
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chico,california
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i think if you want to prove to everybody on this board that your girdle works you need to donate one to a guy like performance only who everbody knows from the board but he would need to put it on a real motor say 1000hp or so just my two cents

Re: Why do only Mopars experience "cap walk"??? [Re: CRE2004] #13713
12/24/04 10:14 AM 12/24/04 10:14 AM

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I'm glad we were able to help them out and it looks as though we'll be machining them a new block for next season...


Just curious, why the new block if everything looked OK on the tear down?

Re: Why do only Mopars experience "cap walk"??? [Re: CRE2004] #13714
12/24/04 11:37 AM 12/24/04 11:37 AM
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we ran a 448 in our Duster.. we had main bearing failure which led to a snapped rod..when I tore down the engine,cap walk was very evident.This engine was an easy rever to 7800 but was never shifted higher than 6800...our new engine is a 499 which is now making in excess of 800+hp..we have as you know your stud girdle and I have found it very smooth..of course my wife races the car so trying to pull data out of her is...you know...we only made 3 runs since the season ended clocking an amazing 9.23 shutting down at 1000' and soft launch...Becky's remarks were"It's so smooth and POWERFUL"(a woman's insight to just about everything)..she has all the confidence in the world with this new engine...on the dyno it was smooth past 7500...when we teardown next season..we will see how well a 2 bolt main and stud girdle will do on bearings.....
Re: Why do only Mopars experience "cap walk"??? [Re: smokinwoody] #13715
12/24/04 02:06 PM 12/24/04 02:06 PM
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East Lansing, Michigan
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A few years back, before buying my Mega Block, I inquired about any strength issues that the stock Ductile Iron Cross Bolted main caps might have. Muscle Motors replied that they had not had any issues at 1300+ Horsepower, but I am thinking that may have been Dyno blasts, not on track testing. So, would using either stud girdle in conjuction with the Ductile Iron mains and Cross Bolting be practicle at, say, 700 HP or so? Overkill? Tossing good money after bad? This in a 3400+ Lb. "B" body. I am a firm believer in building killer bottom ends, it tends to save $$$$ in the long run.

The Old Hippie Hisself
Re: Why do only Mopars experience "cap walk"??? [Re: OldHippie] #13716
12/24/04 03:30 PM 12/24/04 03:30 PM

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Being new to the "Mopar world" a few years ago.. I built my first hard core r/b engine. I had heard of the block problems, As I had done a few mild builds in the past. This engine I`m speaking of was gonna make some big #`s. W/ that in mind, I set off to think of what I should do to help deal w/ this problem... I had been working on imports for some time and seen how they would tie the mains together, Also seeing the systems that were already out there for the S/B Chevys and Fords, Even though its a different design block. Not knowing anything about "old" hard core mopar guys, In the past making anything like a main girdle plate(How true this is, I dont know).. The next logical thought I had was, I GOTTA make something to tie this week block together and get the main caps and block from poping!!
So, without any "outside" help, I designed the plate system.. You know, Thats the one that EVERYONE talks about now!!! From what I gather, nobody was really thinking about it much, until I started selling them on ebay a few years ago.. At that time I didnt pay ANY attention to the Mopar web site, I just got outside info from people who did, And they said your main girdle system is being talked about on the forums.. Next thing I know is, Everybody and there mother said, "Look at this great idea I had.. This is the ticket!! YOU NEED A MAIN GIRDLE PLATE!!
Its great that an "old" Chevy guy, Could be such a help to u guys!!
Really, I work on them ALL! I do not like putting blinders on and only working on one brand of engine.. I think by being SO closed minded, To think that there is nothing else out there but MOPAR,just hurts your ability as an engine builder.. I`m not degrading the abilitys of Mopars to run.. I have been VERY impressed w/ the ones I have built!!! Look at my little pump gasser! Out of the box, With nothing more than a stock cranked 446, W/ no tune and a 1.48 60ft... 9.75 @ 140mph!
Let the bashing begin!!

Re: Why do only Mopars experience "cap walk"??? #13717
12/24/04 05:21 PM 12/24/04 05:21 PM
Joined: Nov 2003
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Illinois
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Quote:


Just curious, why the new block if everything looked OK on the tear down?


They're putting together a new B1 engine and keeping this years as a backup. The new one should turn 9000rpm.

Re: Why do only Mopars experience "cap walk"??? [Re: smokinwoody] #13718
12/24/04 05:24 PM 12/24/04 05:24 PM
Joined: Nov 2003
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Illinois
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Illinois
Quote:

...on the dyno it was smooth past 7500...when we teardown next season..we will see how well a 2 bolt main and stud girdle will do on bearings....


Thanks Jeff, I'm looking forward to seeing the bearings too...should look good!

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