Hello! Log in or Register   |  Help  |  Donate  |  Buy Shirts See all banner ads | Advertise on TheSamba.com  
TheSamba.com
 
Stroker engine deck height question
Forum Index -> Vintage Speed 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
Braukuche
Samba Member


Joined: September 03, 2004
Posts: 10968

Braukuche is offline 

PostPosted: Mon Jan 05, 2009 5:31 pm    Post subject: Stroker engine deck height question Reply with quote

I checked my deck height today on my 36 horse Okrassa clone stroker (69 mm) and the piston sticks about 1.94mm above the jug. In order to get factory compression what thickness of ring would I need? Would the copper ring affect this measurement by-the-way?
--Dan
Back to top
View user's profile Send private message Gallery Classifieds Feedback
mightymouse
Samba Member


Joined: May 26, 2004
Posts: 4220
Location: las vegas
mightymouse is offline 

PostPosted: Tue Jan 06, 2009 6:18 pm    Post subject: Reply with quote

Id suggest you dont shoot for factory compression. What cam will you be using?
That is the equation. Do the math for dynamic, and static compression, using your choice of cam, and that will tell you where to set your static CR.
Id say deck it at .050"
So youd need a 3.2mm spacer or .127"
Then you can plunge cut the heads a tad to get your compression where you want it.

Last 1600 i did, has a scat C25 cam in it. 9.4 to 1 static compression, and the dynamic compression with that cam is around 7.7 to 1
SO the motor is nice and snappy/responsive, but once its in driving rpm, the compression is perfect for a clean burn, and the heads stay cool.
Youll prob end up setting you static at 8.5 to 1 depending on cam and carbs you use. Smile
_________________
Nothing can stop the man with the right mental attitude from achieving his goal; nothing on earth can help the man with the wrong mental attitude.
Thomas Jefferson


Note to EVERYONE.
Know your ZDDP levels or you WILL lose a cam and lifters.
Back to top
View user's profile Send private message Send e-mail AIM Address Yahoo Messenger Gallery Classifieds Feedback
Braukuche
Samba Member


Joined: September 03, 2004
Posts: 10968

Braukuche is offline 

PostPosted: Tue Jan 06, 2009 7:56 pm    Post subject: Reply with quote

mightymouse wrote:
Id suggest you dont shoot for factory compression. What cam will you be using?
That is the equation. Do the math for dynamic, and static compression, using your choice of cam, and that will tell you where to set your static CR.
Id say deck it at .050"
So youd need a 3.2mm spacer or .127"
Then you can plunge cut the heads a tad to get your compression where you want it.

Last 1600 i did, has a scat C25 cam in it. 9.4 to 1 static compression, and the dynamic compression with that cam is around 7.7 to 1
SO the motor is nice and snappy/responsive, but once its in driving rpm, the compression is perfect for a clean burn, and the heads stay cool.
Youll prob end up setting you static at 8.5 to 1 depending on cam and carbs you use. Smile


Thanks for the info. If I run a 3.2mm spacer, how will that affect my pushrods? What can I do to compensate for the extra distance? I know Okrasa supplied spacers with their kits but did they also include longer pushrods??
--Dan
Back to top
View user's profile Send private message Gallery Classifieds Feedback
mightymouse
Samba Member


Joined: May 26, 2004
Posts: 4220
Location: las vegas
mightymouse is offline 

PostPosted: Tue Jan 06, 2009 10:17 pm    Post subject: Reply with quote

Braukuche wrote:
mightymouse wrote:
Id suggest you dont shoot for factory compression. What cam will you be using?
That is the equation. Do the math for dynamic, and static compression, using your choice of cam, and that will tell you where to set your static CR.
Id say deck it at .050"
So youd need a 3.2mm spacer or .127"
Then you can plunge cut the heads a tad to get your compression where you want it.

Last 1600 i did, has a scat C25 cam in it. 9.4 to 1 static compression, and the dynamic compression with that cam is around 7.7 to 1
SO the motor is nice and snappy/responsive, but once its in driving rpm, the compression is perfect for a clean burn, and the heads stay cool.
Youll prob end up setting you static at 8.5 to 1 depending on cam and carbs you use. Smile


Thanks for the info. If I run a 3.2mm spacer, how will that affect my pushrods? What can I do to compensate for the extra distance? I know Okrasa supplied spacers with their kits but did they also include longer pushrods??
--Dan


Damn, good queston. I need to do some more looking. There has to have been a few people who have had made, or found a way to lengthen the stockers. Since they are 1 piece, i see where you dilemma is.
IF that proves to be too big a challenge, you could always call wiseco, or CP, or any of the other 50 piston manufacturers, and then give them your dimensions and they will make you new pistons. Moving the pin higher would get you juuust right. Smile
You could stay with stock width then, so all your tin will fit correctly.
If you do that, may as well have them make you 3 or 4 sets. Then sell em.
Let us know which route you choose. talk soon. dave
_________________
Nothing can stop the man with the right mental attitude from achieving his goal; nothing on earth can help the man with the wrong mental attitude.
Thomas Jefferson


Note to EVERYONE.
Know your ZDDP levels or you WILL lose a cam and lifters.
Back to top
View user's profile Send private message Send e-mail AIM Address Yahoo Messenger Gallery Classifieds Feedback
Braukuche
Samba Member


Joined: September 03, 2004
Posts: 10968

Braukuche is offline 

PostPosted: Wed Jan 07, 2009 7:01 am    Post subject: Reply with quote

mightymouse wrote:
Braukuche wrote:
mightymouse wrote:
Id suggest you dont shoot for factory compression. What cam will you be using?
That is the equation. Do the math for dynamic, and static compression, using your choice of cam, and that will tell you where to set your static CR.
Id say deck it at .050"
So youd need a 3.2mm spacer or .127"
Then you can plunge cut the heads a tad to get your compression where you want it.

Last 1600 i did, has a scat C25 cam in it. 9.4 to 1 static compression, and the dynamic compression with that cam is around 7.7 to 1
SO the motor is nice and snappy/responsive, but once its in driving rpm, the compression is perfect for a clean burn, and the heads stay cool.
Youll prob end up setting you static at 8.5 to 1 depending on cam and carbs you use. Smile


Thanks for the info. If I run a 3.2mm spacer, how will that affect my pushrods? What can I do to compensate for the extra distance? I know Okrasa supplied spacers with their kits but did they also include longer pushrods??
--Dan


Damn, good queston. I need to do some more looking. There has to have been a few people who have had made, or found a way to lengthen the stockers. Since they are 1 piece, i see where you dilemma is.
IF that proves to be too big a challenge, you could always call wiseco, or CP, or any of the other 50 piston manufacturers, and then give them your dimensions and they will make you new pistons. Moving the pin higher would get you juuust right. Smile
You could stay with stock width then, so all your tin will fit correctly.
If you do that, may as well have them make you 3 or 4 sets. Then sell em.
Let us know which route you choose. talk soon. dave


Geez, I didn't even think of the tin. You would also end up with a gap there as well. I guess that's why the PO ground the pistons down to make up the difference in the old engine. Maybe that's the route to go, but with a domed piston I wonder if I would get high compression?
--Dan
Back to top
View user's profile Send private message Gallery Classifieds Feedback
hugheseum
Samba Member


Joined: February 11, 2004
Posts: 2690
Location: oregon
hugheseum is offline 

PostPosted: Wed Jan 07, 2009 8:59 am    Post subject: Reply with quote

harley davidson pistons
_________________
Have a great day!
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
oval56
Samba Member


Joined: July 21, 2003
Posts: 1309
Location: oktoberfest maintown
oval56 is offline 

PostPosted: Wed Jan 07, 2009 10:40 am    Post subject: Reply with quote

for the pushrods, you have to machine some shims on the lathe in 3mm wich you can mount between the pushrod bottom and the tube as distance to length it... like okrasa has written it in the manual

or you machine longer ones (i have to machine it 6mm longer!)

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.

_________________
www.oval56.com

1956 Oval, 2364ccm typ4
1957 Oval Ragtop 1584ccm singel port modified
1950 Hebmüller, 1584ccm okrasa modified

DBK Germany!!!!!!!!!!
www.dbkvw.com
Back to top
View user's profile Send private message Send e-mail Visit poster's website Gallery Classifieds Feedback
Braukuche
Samba Member


Joined: September 03, 2004
Posts: 10968

Braukuche is offline 

PostPosted: Wed Jan 07, 2009 7:35 pm    Post subject: Reply with quote

I found a little more info searching around and apparently Okrassa inlcuded 3mm spacers for the pushrods. Those should be no problem to make as a I have tons of spare pushrods, but the spacers for the barrel...not so easy. I know WolfsburgWest makes them, but the largest is .060", so I would have to use a combination. Is using multiple barrel spacers a bad idea? If so, any idea where I can find them?
--Dan
Back to top
View user's profile Send private message Gallery Classifieds Feedback
mightymouse
Samba Member


Joined: May 26, 2004
Posts: 4220
Location: las vegas
mightymouse is offline 

PostPosted: Wed Jan 07, 2009 10:53 pm    Post subject: Reply with quote

Id bet money, the piston you need already exists. Call a few piston companies, tell em the diameter, the current pin height, and the pin height you need, and they will check their database. prob have the piston in stock. You can prob get em for 60 or so a piston. Make sure they know its an aircooled application, not water cooled.
That would be WAY easier than all this other drama. and same width engine. fits in car better, exhausts fit better, tin fits, sheesh. Like adam said, harley pistons. prob work perf. Smile
_________________
Nothing can stop the man with the right mental attitude from achieving his goal; nothing on earth can help the man with the wrong mental attitude.
Thomas Jefferson


Note to EVERYONE.
Know your ZDDP levels or you WILL lose a cam and lifters.
Back to top
View user's profile Send private message Send e-mail AIM Address Yahoo Messenger Gallery Classifieds Feedback
SGM
Samba Member


Joined: December 18, 2007
Posts: 8
Location: Glenn Dale, Maryland
SGM is offline 

PostPosted: Thu Jan 08, 2009 1:40 am    Post subject: Reply with quote

RIMCO should be able to machine the spacers you need.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Braukuche
Samba Member


Joined: September 03, 2004
Posts: 10968

Braukuche is offline 

PostPosted: Thu Jan 08, 2009 7:14 am    Post subject: Reply with quote

mightymouse wrote:
Id bet money, the piston you need already exists. Call a few piston companies, tell em the diameter, the current pin height, and the pin height you need, and they will check their database. prob have the piston in stock. You can prob get em for 60 or so a piston. Make sure they know its an aircooled application, not water cooled.
That would be WAY easier than all this other drama. and same width engine. fits in car better, exhausts fit better, tin fits, sheesh. Like adam said, harley pistons. prob work perf. Smile



At the risk of sounding stupid, if I go this route then won't I negate the extra distance I get with the stroke. In other words, the piston will no longer be traveling the same distance as if I used spacers, right?
--Dan
Back to top
View user's profile Send private message Gallery Classifieds Feedback
mightymouse
Samba Member


Joined: May 26, 2004
Posts: 4220
Location: las vegas
mightymouse is offline 

PostPosted: Thu Jan 08, 2009 11:51 am    Post subject: Reply with quote

Braukuche wrote:
mightymouse wrote:
Id bet money, the piston you need already exists. Call a few piston companies, tell em the diameter, the current pin height, and the pin height you need, and they will check their database. prob have the piston in stock. You can prob get em for 60 or so a piston. Make sure they know its an aircooled application, not water cooled.
That would be WAY easier than all this other drama. and same width engine. fits in car better, exhausts fit better, tin fits, sheesh. Like adam said, harley pistons. prob work perf. Smile



At the risk of sounding stupid, if I go this route then won't I negate the extra distance I get with the stroke. In other words, the piston will no longer be traveling the same distance as if I used spacers, right?
--Dan


You never sound stupid, you simply learn.

No... crankshaft determines stroke.

The piston will travel the same distance up and down no matter what piston or rod you use.
What i suggested will simply move the piston pin closer to the ring lands, thus moving the head of the piston down, and getting your piston top below then end of the barrel.
See the difference between A and B pistos for an example. mahle makes an A for all regular air cooled motors, and B pistons for strokers, to keep the engine at a manageable width.
A 2007cc motor with flycut heads, and B pistons, is more narrow than a 1600, its actually the same width as a 36 hp. Smile

Now you know more. Smile any other Q's ask away. we all love to help.
_________________
Nothing can stop the man with the right mental attitude from achieving his goal; nothing on earth can help the man with the wrong mental attitude.
Thomas Jefferson


Note to EVERYONE.
Know your ZDDP levels or you WILL lose a cam and lifters.
Back to top
View user's profile Send private message Send e-mail AIM Address Yahoo Messenger Gallery Classifieds Feedback
Braukuche
Samba Member


Joined: September 03, 2004
Posts: 10968

Braukuche is offline 

PostPosted: Mon Jan 12, 2009 12:35 pm    Post subject: Reply with quote

Just a follow up for the archives...
I ended up going with spacers to shim out my cylinders to get the appropriate deck height. I bought pistons from two different suppliers: one set from Wolfsburgwest and the other from Matthew who sells 36 engine parts. The set from Matthew had wide skirts and would not clear the crank, They could of course be ground down, but I found the WW set had much narrower skirts and easily cleared the crank, so no grinding needed.
I have the longblock assembled and the engine spins nice. I still need to put the rockers on and deal with the pushrod issue. Thanks to a fellow Sambanista I know that I need to use 3mm spacers for the pushrods. I assume the spacers go between the rod and the lifter. Since these are one piece, I wonder how it is best to separate and then reassemble the rod? I have plenty of extras to experiment on but if anyone has any experience with this I would appreciate any ideas.
--Dan
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Display posts from previous:   
Reply to topic    Forum Index -> Vintage Speed All times are Mountain Standard Time/Pacific Daylight Savings Time
Page 1 of 1

 
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 © 1996-2023, Everett Barnes. All Rights Reserved.
Not affiliated with or sponsored by Volkswagen of America | Forum powered by phpBB
Links to eBay or other vendor sites may be affiliate links where the site receives compensation.