Hello! Log in or Register   |  Help  |  Donate  |  Buy Shirts  See all banner ads | Advertise on TheSamba.com  
TheSamba.com
 
Clearancing: 92mm AA Pistons, 76mm Stroker, & 5.325"
Page: 1, 2, 3  Next
Forum Index -> Performance/Engines/Transmissions Share: Facebook Twitter
Reply to topic
Print View
Quick sort: Show newest posts on top | Show oldest posts on top View previous topic :: View next topic  
Author Message
palmettofx
Samba Member


Joined: December 01, 2013
Posts: 48

palmettofx is offline 

PostPosted: Sat Dec 14, 2013 5:04 pm    Post subject: Clearancing: 92mm AA Pistons, 76mm Stroker, & 5.325" Reply with quote

I have a set of 92x69 thickwall (94 top, 90.5/92 bottom) AA Performance P/C's that I bought for my bug before finding that the case that came with the car is junk.

I figured since I had to get a new case that I would go a little larger and get a low/middle stroker crank, 74/76mm, to go with my 92mm pistons.

ACN says I can use both a 74/76 crank with their 5.325 rods without too much clearancing fuss in their budget stroker article. When I go to look at the 5.325 rods to buy them they have the note stating piston skirt clearance will most likely be an issue with 76 cranks.

My question is, would anyone who's used AA 92mm pistons with a 74/76mm crank, & 5.325" rods have any insight on this specific combination of parts? I'd like to get a 76 but my feelings wouldn't be hurt with a 74mm crank.

To be as specific as I can, here's what I'm considering
Crank
Rods
Pistons

I understand this might be a shot in the dark but I figured I would see if anyone has this combo. I searched and didn't see any AA brand clearancing posts.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
modok
Samba Member


Joined: October 30, 2009
Posts: 22774
Location: Colorado Springs
modok is offline 

PostPosted: Sat Dec 14, 2013 5:11 pm    Post subject: Reply with quote

AA's "a" pistons are are dimensionally a copy of mahle
I have used 92 "A" mahle pistons with 74 and 76 AND 78 strokes several times before, and never had to clearance the skirts.

The .070 shorter rod is like having 3mm more stroke, so.....with 74 I would not even check.
With 76-78 stroke it probably will clear, but I would take a look before balancing the pistons.

Verses a stock piston, the 92 are shorter skirt, and bigger diameter, thus less tendency to hit the crank!
_________________
-defund facebook-
Back to top
View user's profile Send private message Gallery Classifieds Feedback
itHaKa
Samba Member


Joined: February 20, 2008
Posts: 253
Location: Argentina
itHaKa is offline 

PostPosted: Sat Dec 14, 2013 5:18 pm    Post subject: Reply with quote

this is what my brother had to do to the skirts of his AA pistons in 88 mm
76 crank and 5.4 rods, ( 1849cc) so i assume if you use 5.3 rods and a 76 crank you will have to do it even more

Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.


complete build in my signature .
_________________
76x88 , 1849cc engine build :
http://mundoescarabajo.com.ar/me/viewtopic.php?t=635
Back to top
View user's profile Send private message Visit poster's website Gallery Classifieds Feedback
bugguy076
Samba Member


Joined: December 11, 2007
Posts: 1068
Location: Dover, PA.
bugguy076 is offline 

PostPosted: Sat Dec 14, 2013 5:28 pm    Post subject: Reply with quote

I run a 76 strokeX92A pistons with stock length H beam rods. I think the spacers are .060. The shift point is at 7200. I have run the combo for 4 years in a drag car with no problems. No clearance troubles with stock length rods.
Back to top
View user's profile Send private message Classifieds Feedback
palmettofx
Samba Member


Joined: December 01, 2013
Posts: 48

palmettofx is offline 

PostPosted: Sat Dec 14, 2013 6:37 pm    Post subject: Reply with quote

Thank you all for your advice!
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Danwvw
Samba Member


Joined: July 31, 2012
Posts: 8498
Location: Oregon Coast
Danwvw is offline 

PostPosted: Sat Dec 14, 2013 7:03 pm    Post subject: Reply with quote

The Short rods are going to be the problem. They will likely need something like this:
Image may have been reduced in size. Click image to view fullscreen.

_________________
1971 VW Bus Sundial Camper, 1960 VW Beetle Building a 74 mm Stroke by 88 mm bore with stock heads? And 1960 Beetle And Porsche Carbs!
Back to top
View user's profile Send private message Send e-mail Facebook Twitter Gallery Classifieds Feedback
palmettofx
Samba Member


Joined: December 01, 2013
Posts: 48

palmettofx is offline 

PostPosted: Sat Dec 14, 2013 7:24 pm    Post subject: Reply with quote

So if I got some Hbeam 5.4" aftermarket rods this would keep them up?

The reason I was brought on to the 5.3's was I was taking with someone about it at work Friday and he mentioned they were available. I didn't really think about it but I'm not sure I really want to get a stroker crank just to negate the stroke with a shorter rod. Seems counterproductive.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Dan Ruddock
Samba Member


Joined: October 25, 2012
Posts: 2683
Location: Sarasota, FL.
Dan Ruddock is offline 

PostPosted: Sat Dec 14, 2013 7:24 pm    Post subject: Reply with quote

Hell, I am building an 84mm motor with 912 rods (5.354) with mahle 90.5 b's if there is a will there is a way. I would use a 78 crank if I were you. Better yet get some b pistons 5.400 rods and build a 82mm motor. Don't let having to do some clearancing scare you it is not that big a deal. Dan
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Dan Ruddock
Samba Member


Joined: October 25, 2012
Posts: 2683
Location: Sarasota, FL.
Dan Ruddock is offline 

PostPosted: Sat Dec 14, 2013 7:32 pm    Post subject: Reply with quote

palmettofx wrote:
So if I got some Hbeam 5.4" aftermarket rods this would keep them up?

The reason I was brought on to the 5.3's was I was taking with someone about it at work Friday and he mentioned they were available. I didn't really think about it but I'm not sure I really want to get a stroker crank just to negate the stroke with a shorter rod. Seems counterproductive.

Nothing counterproductive about it, the vw engine had a longer than necessary rod to begin with and adding stroke without adding rod length hurts nothing. Dan
Back to top
View user's profile Send private message Gallery Classifieds Feedback
palmettofx
Samba Member


Joined: December 01, 2013
Posts: 48

palmettofx is offline 

PostPosted: Sat Dec 14, 2013 7:39 pm    Post subject: Reply with quote

It's not necessarily the clearancing that scares me, I have a machine shop that's been pretty cool thus far just a few miles from work.

It's just that I've already bought the 92x69 AA pistons and I don't really want to go through the hassle of returning them. I sent them an email asking about an RMA since they're still in the box, untouched, so I guess I'm not against going to a larger stroker.

Dan Ruddock wrote:
Nothing counterproductive about it, the vw engine had a longer than necessary rod to begin with and adding stroke without adding rod length hurts nothing. Dan


Counterproductive in my case, I meant.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
modok
Samba Member


Joined: October 30, 2009
Posts: 22774
Location: Colorado Springs
modok is offline 

PostPosted: Sat Dec 14, 2013 7:47 pm    Post subject: Reply with quote

I really don't see any problems, and to clearance the skirts is very easy anyway, just takes time, which I'll assume you have a little to spare.
I have 5.3 rods and mahle 92 a and 78 DMS racewight crank, maybe I mock this up real quick. Wink
_________________
-defund facebook-


Last edited by modok on Sat Dec 14, 2013 7:48 pm; edited 1 time in total
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Dan Ruddock
Samba Member


Joined: October 25, 2012
Posts: 2683
Location: Sarasota, FL.
Dan Ruddock is offline 

PostPosted: Sat Dec 14, 2013 7:47 pm    Post subject: Reply with quote

82mm crank costs about the same as a 76 so why not? The bigger the crank the nicer it drives but one thing to keep in mind is the longer the stroke the weaker the crank will be and the more necessary it is for a quality piece. Dan
Back to top
View user's profile Send private message Gallery Classifieds Feedback
palmettofx
Samba Member


Joined: December 01, 2013
Posts: 48

palmettofx is offline 

PostPosted: Sat Dec 14, 2013 7:57 pm    Post subject: Reply with quote

Dan Ruddock wrote:
82mm crank costs about the same as a 76 so why not? The bigger the crank the nicer it drives but one thing to keep in mind is the longer the stroke the weaker the crank will be and the more necessary it is for a quality piece. Dan


I was pricing cranks from CBPerformance, where the 74/76 cranks are about 100$ cheaper than the 78+ cranks. As well as having A pistons that I'd have to return and get replacements.

There is no rush for this build, I have all winter - I'm just not a huge fan of returning things and paying the fancy shipping for the heavy jugs would not be fun.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
modok
Samba Member


Joined: October 30, 2009
Posts: 22774
Location: Colorado Springs
modok is offline 

PostPosted: Sat Dec 14, 2013 8:00 pm    Post subject: Reply with quote

it clears by over .100"
_________________
-defund facebook-
Back to top
View user's profile Send private message Gallery Classifieds Feedback
palmettofx
Samba Member


Joined: December 01, 2013
Posts: 48

palmettofx is offline 

PostPosted: Sat Dec 14, 2013 8:13 pm    Post subject: Reply with quote

You are a gentleman and a saint.

What is the reasoning to using the 5.3" rods in your application with a 78 stroker? You're essentially ending up with a 76mm crank after the shorter rots coupled with the 78mm crank, right? Why not run factory length and 76? I'm asking in curiosity, not doubt.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
modok
Samba Member


Joined: October 30, 2009
Posts: 22774
Location: Colorado Springs
modok is offline 

PostPosted: Sat Dec 14, 2013 8:19 pm    Post subject: Reply with quote

I made the 5.3 rods for the next time I build a 74 or 76 stroke, the old 92 mahle A pistons are spares.

The crank is for something else, it will have 5.5 eagle rods and B pistons Wink

so really, I the parts are unrelated, but do fit together Laughing
_________________
-defund facebook-
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Dan Ruddock
Samba Member


Joined: October 25, 2012
Posts: 2683
Location: Sarasota, FL.
Dan Ruddock is offline 

PostPosted: Sat Dec 14, 2013 8:24 pm    Post subject: Reply with quote

A 78mm crank is 78mm no matter what rods you use. The CB 82mm cranks are more because they are 4340 vs. 4140 (better steel). A dpr welded crank is about the same price 78 to 82. Dan
Back to top
View user's profile Send private message Gallery Classifieds Feedback
palmettofx
Samba Member


Joined: December 01, 2013
Posts: 48

palmettofx is offline 

PostPosted: Sat Dec 14, 2013 9:08 pm    Post subject: Reply with quote

I didn't mean the crank was shorter with different rods, but the effective stroke would be - or am I completely off on this?
Back to top
View user's profile Send private message Gallery Classifieds Feedback
modok
Samba Member


Joined: October 30, 2009
Posts: 22774
Location: Colorado Springs
modok is offline 

PostPosted: Sat Dec 14, 2013 9:17 pm    Post subject: Reply with quote

yeah, I figure you mean "Deck height"
"Deck height" in the main engine building world means the distance from the crank center to where the head bolts on, and we like to keep this near the stock 212.5mm

In the vw world deck height can also means quench clearance, which, IMO just creates confusion.
_________________
-defund facebook-
Back to top
View user's profile Send private message Gallery Classifieds Feedback
esde
Samba Member


Joined: October 20, 2007
Posts: 4379
Location: central rust belt
esde is offline 

PostPosted: Sat Dec 14, 2013 9:21 pm    Post subject: Reply with quote

I am not sure what you mean by "effective stroke", my suggestion is that you read up on "rod ratio". Different length rods change the leverage that the rod has on the crankshaft.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Display posts from previous:   
Reply to topic    Forum Index -> Performance/Engines/Transmissions All times are Mountain Standard Time/Pacific Daylight Savings Time
Page: 1, 2, 3  Next
Page 1 of 3

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

About | Help! | Advertise | Donate | Premium Membership | Privacy/Terms of Use | Contact Us | Site Map
Copyright © 1996-2020, Everett Barnes. All Rights Reserved.
Not affiliated with or sponsored by Volkswagen of America | Forum powered by phpBB