home register FAQ memberlist calendar

Go Back   Turbobricks Forums > Mechanical > performance & modifications

Reply
 
Thread Tools Display Modes
Old 11-12-2011, 09:37 PM   #1
forman621
Board Member
 
forman621's Avatar
 
Join Date: Nov 2010
Location: Selah, WA
Default Bottom end? Can it hold?

So I have rebuilt the bottom end on my b21ft with just new bearings and rings and block cleaned and what not. so pretty much a good condition stock bottom end.

My top end is or will be and have parts for.

Volvo 531 penta head
porting
.005 shave on intake
.020 shave on exhaust
Heavy duty valve springs rated to around 7500rpm
New everything else
seal, retainers, guides

I am putting in SS valves
46mm Intake
38mm Exhaust

My question is
Should i have done more to the bottom end to run this head setup?
forman621 is offline   Reply With Quote
Old 11-12-2011, 09:43 PM   #2
DNAsEqUeNcE
†John3:16
 
DNAsEqUeNcE's Avatar
 
Join Date: Jan 2009
Location: HTX
Default

nope!

boost it!!

But really a much lighter rotating assembly from respectable dealers on this board would be a good option, the b21ft rotating assembly is heaaaaaaaaaaaaaaavayyyyy.

they are bullet proof though.
__________________
DNAsEqUeNcE is offline   Reply With Quote
Old 11-12-2011, 09:59 PM   #3
viking20
Board Member
 
Join Date: Mar 2009
Default

I dont think its ideal to have the 531 head on the smaller bore , and esp not the larger valves ?
viking20 is offline   Reply With Quote
Old 11-12-2011, 10:02 PM   #4
forman621
Board Member
 
forman621's Avatar
 
Join Date: Nov 2010
Location: Selah, WA
Default

I am thinking about those rsi H beam rods.
But i am not sure what pistons i should use.
And if i get lighter pistons and rods would the crank need balanced?

And i am going to be running an IPD turbo cam
forman621 is offline   Reply With Quote
Old 11-12-2011, 10:10 PM   #5
PRVersion
regretting name change
 
PRVersion's Avatar
 
Join Date: Feb 2005
Location: Portland
Default

Quote:
Originally Posted by viking20 View Post
I dont think its ideal to have the 531 head on the smaller bore , and esp not the larger valves ?
i've done effectively the same thing with non-volvo engines, the only difference is that you lose a little low RPM potential. maybe.
__________________
Quote:
Originally Posted by XxJenoxX View Post
PRVersion wins.
Quote:
Originally Posted by golgothan View Post
accelerate til the last possible moment, then accelerate more...
PRVersion is offline   Reply With Quote
Old 11-12-2011, 10:18 PM   #6
FlyingTog
B6304 douche
 
FlyingTog's Avatar
 
Join Date: Aug 2007
Location: Cape May County, New Jersey
Default

How psi a stock can support?
__________________
Quote:
Originally Posted by Crazychopstick View Post
Just a 960 bumper returning to its original form.
97 965R M90 My car! It's Purple! 263K+! 15.66@89.14
83 Group A 242. 7k+ original miles. Long term project.
98 V90 Parts car. Silver 225k+
98 V90 Mom's car. Dark Green. 195K+
59 Austin Healey Bugeye Sprite. Project car.
94 Miata. Weekend car with 55K+ original miles!
94 Miata. LeMons project.

960 build thread: http://forums.turbobricks.com/showthread.php?t=231763
FlyingTog is offline   Reply With Quote
Old 11-12-2011, 10:22 PM   #7
forman621
Board Member
 
forman621's Avatar
 
Join Date: Nov 2010
Location: Selah, WA
Default

I dont know what they should be able to hold. i have heard around 15 psi right?
forman621 is offline   Reply With Quote
Old 11-13-2011, 01:33 AM   #8
GT_Paul
Elephant in the room
 
GT_Paul's Avatar
 
Join Date: Jan 2005
Location: Tasmania, Australia
Default

I have has a 531 on a 21 and the gasket was very close to the chamber.
Have read here that they tend to blow under stress. mine didn't but maybe use a 2.3 gasket..
I run 25 psi, no problems....
__________________
79 242 GT+T
GT_Paul is offline   Reply With Quote
Old 11-13-2011, 02:51 AM   #9
fast242
I had a Jewish wedding
 
fast242's Avatar
 
Join Date: Feb 2003
Location: Cerritos CA
Default

B21FT head gasket, and go for 30 psi if the rest of your set up can handle it. B21FT's are friggen stout, but as Brett said, heavy internally. The smaller bore and low compression help immensely if you run high boost.

If Budget allows, try to lighten the internals and longer rods and better pistons, but keep the bore size the same and have fun. RSI would be the likely outlet for those goodies.

PJ
__________________
84 242Ti 16V build up
83 245Ti daily driver lots of common mods
1992 745Ti stock
16V Block mounted LH2.2 distributors for 16V conversions on 240's, now for sale, just click this link
Pics Of the 242 and other stuff
http://www.pbase.com/fast242
fast242 is offline   Reply With Quote
Old 11-13-2011, 03:31 AM   #10
forman621
Board Member
 
forman621's Avatar
 
Join Date: Nov 2010
Location: Selah, WA
Default

Stock rods are 145 mm and they reccomend the 154 with new pistons
forman621 is offline   Reply With Quote
Old 11-13-2011, 04:19 AM   #11
forman621
Board Member
 
forman621's Avatar
 
Join Date: Nov 2010
Location: Selah, WA
Default

So rsi has a set of pistons that use stock length rods at - 145mm
and they also offer piston set that uses - 156mm rods.
Piston spec is 92.5mm
I have C and D cylinders which range from C 92.6992 - 92.08008 and D 92.08008 - 92.09024
so it will have to be bored is what i am thinking.
I am using a cometic head gasket at 0.036" with a bore size of 94 mm. I bought this from Knox

what would be the difference between running stock length rods VS the slightly longer 156mm rods?
forman621 is offline   Reply With Quote
Old 11-13-2011, 04:52 AM   #12
RESURRECTED
back from the dead.
 
RESURRECTED's Avatar
 
Join Date: Oct 2009
Location: boggs-- norcal hills
Default

running the longer rods will lighten the piston end of the rotating assembly (very good thing)
one of the biggest issues when taking a engine to higher RPMs and bringing those RPMs back down in a controlled manner is figuring what,where and how to lighten things up, so they rev faster, and remain intact.
if your going for RSI pistons and rods, go for long rods. though at that point I wouldn't want to run such low compression as factory... I prefer throttle response with my power, unless your takin it to the 1/4 mile.
__________________
my brick hauls ass on its jack stands
RESURRECTED is offline   Reply With Quote
Old 11-13-2011, 04:54 AM   #13
RESURRECTED
back from the dead.
 
RESURRECTED's Avatar
 
Join Date: Oct 2009
Location: boggs-- norcal hills
Default

really though, you should give RSI a phone call.
RESURRECTED is offline   Reply With Quote
Old 11-13-2011, 12:00 PM   #14
forman621
Board Member
 
forman621's Avatar
 
Join Date: Nov 2010
Location: Selah, WA
Default

Yeah I probably will tomorrow. Thanks you guys for the advice.
I was hoping to bring the compression up a little. So it doesn't have to rely in boost all the time.
forman621 is offline   Reply With Quote
Old 11-13-2011, 01:47 PM   #15
olov
doing something stupid
 
olov's Avatar
 
Join Date: Aug 2003
Location: warrenton, nc 27589
Default

ok, i've got a 130k b21ft with a ported 530 head w/upgraded springs. so i am in the same ballpark as you. the bottom end is fine, i just don't feel ok throwing those big heavy pistons around over 7500-8000. i wouldn't be surprised if some sweeds have done it, but really, i don't need to go that high most of the time. i just wanted the spring upgrade for peace of mind.

the head is basically the same as my 530, it works fine, just use a b21ft head gasket.

to upgrade the rods/pistons.......i wouldn't bother, use what you got and see how you like it. if i were gonna buy rods/pistons i'd build a b230 bottom end, much easier to find in good shape, have piston squirters, much more common parts - so easier to find stuff on the shelf/used, and there were people who found really bad casting flaws in the older blocks - so i'd have it sonic tested/etc

good luck, you'll be fine with what you got. and you can reuse the head later if you change to a b230. mine's easily got 300whp, i made 265whp straight off the wastegate at 20psi on a ebay t3/t4, with megasquirt
__________________
Quote:
opinions are like ***holes, i have one, and they're censored on tb
olov is offline   Reply With Quote
Old 11-13-2011, 02:25 PM   #16
MrBill
fige=500Dollar Mistake
 
MrBill's Avatar
 
Join Date: Jan 2006
Location: Southern Maryland
Default

yeah where's my replacement WG actuator?

I don't wanna be a jerk or anything, but I'd rather a JY b230ft freshened up over a stock b21ft bottom end.

And if I were buying rods and pistons, I'd definitely use a b230 bottom end.
__________________
Quote:
Originally Posted by grnmachine02 View Post
Someone say crazy rays?
1978 244dl - Down for paint/16vt
93 245 - Kaplhenke Shortened coilovers with adjustable Koni Reds, adjustable rear spring perches with revalved bilstein S-10 shocks. Turbo 2.5 motor in the works.
10 v50 - Unobtainium T5 R-Design AWD M66
MrBill is offline   Reply With Quote
Old 11-13-2011, 05:45 PM   #17
forman621
Board Member
 
forman621's Avatar
 
Join Date: Nov 2010
Location: Selah, WA
Default

Ok that makes sence I can see how I like it with stock pistons and rods and maybe find b230 to build under it. So I put the stock pistons in and the ring gap I measured was .014" for both top ring and second ring which is the bottom of the range. Which is .014-.022" I think. Is this not a good idea or should I file the rings to get around .016-.018" just to be safe but I don't wasn't it to loose either. I bought the deves rings fron ipd.
forman621 is offline   Reply With Quote
Old 11-13-2011, 06:20 PM   #18
Texas240
Prius Owner
 
Texas240's Avatar
 
Join Date: Jul 2008
Location: Dallas, TX
Default

Quote:
Originally Posted by MrBill View Post
yeah where's my replacement WG actuator?

I don't wanna be a jerk or anything, but I'd rather a JY b230ft freshened up over a stock b21ft bottom end.

And if I were buying rods and pistons, I'd definitely use a b230 bottom end.
When you're at it bore up the pistons, thats what I did on my B230f project
__________________
93 245 LS Engine Swap Project
Texas240 is offline   Reply With Quote
Old 11-13-2011, 06:31 PM   #19
2fast242gt
Do you have a cobalt?
 
Join Date: Nov 2005
Location: appleton WI
Default

Bore the pistons? Really?
__________________
1983 242dl
*6.0 lq4 swaped* Build thread
http://forums.turbobricks.com/showthread.php?t=282323
2fast242gt is offline   Reply With Quote
Old 11-13-2011, 06:41 PM   #20
Texas240
Prius Owner
 
Texas240's Avatar
 
Join Date: Jul 2008
Location: Dallas, TX
Default

Quote:
Originally Posted by 2fast242gt View Post
Bore the pistons? Really?
If he wants beefy and stout bottom, might as well go bigger, bigger will achieve power easier with a little less strain on the internals but im sure you already knew that
Texas240 is offline   Reply With Quote
Old 11-13-2011, 06:45 PM   #21
adrianpike
🔥
 
adrianpike's Avatar
 
Join Date: Dec 2002
Location: Seattle, WA
Default

Quote:
Originally Posted by 2fast242gt View Post
Bore the pistons? Really?
I'm envisioning some sort of ghetto dremeled rollerwave-shaped piston tops
__________________

I'm looking to buy, PM me if you've got any of it: LS bits, 93 850 bumper, ford 8.8", T5 WC, T56, Mustang IRS

Adrian is omniscient, you will never escape his wrath. - 500dollar744ti

doug was here
adrianpike is offline   Reply With Quote
Old 11-13-2011, 07:28 PM   #22
Texas240
Prius Owner
 
Texas240's Avatar
 
Join Date: Jul 2008
Location: Dallas, TX
Default

Quote:
Originally Posted by adrianpike View Post
I'm envisioning some sort of ghetto dremeled rollerwave-shaped piston tops
give me one second and i'll whittle you something with my dremel
Texas240 is offline   Reply With Quote
Old 11-13-2011, 07:35 PM   #23
forman621
Board Member
 
forman621's Avatar
 
Join Date: Nov 2010
Location: Selah, WA
Default

I think my plan is to keep my bullet proof bottom end and not over due it on rpm. I got .036 hg so that brings up the cr. Block was shaved .005-.010" ish I think. Piston is out oo the top of Top bore. About .004"
forman621 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -4. The time now is 08:59 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2018, vBulletin Solutions Inc.