HICKL Posted December 11, 2006 Share Posted December 11, 2006 This may be a basic wuestion but I don't know the answer and failed to find it by searching. I have built a basically stock 350 (1969 motor) for a nother application and during break in noticed the harmonic balancer is all wobbly. It is a 6.75 dia, I have an 8" one laying around, not sure where I got it, can I use it on this 350? Will it effect anything? Thanks Jeff Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted December 11, 2006 Share Posted December 11, 2006 If it has JTR engine mounts, the 8" balancer will hit either the rack, or crossmember. I can't remember which. Quote Link to comment Share on other sites More sharing options...
HICKL Posted December 11, 2006 Author Share Posted December 11, 2006 This is not for my Z, just a generec SBC 350 question. If the motor had a 6.75 dia balancer, can I use this 8" OEM balancer instead? Does it effect anything functionally. Quote Link to comment Share on other sites More sharing options...
jnjdragracing Posted December 11, 2006 Share Posted December 11, 2006 Remember sbc 350 are internal balanced. Yes the 8" balancer will work as long as it is for a 350. Remember they also made 8" balancers for sbc 400 which are externally balanced. My rule of thumb is 6.75 are 350 internal and 8" factory balancers are external for 400. Need to be damn sure it is not a 400 balancer before installing it. If you turn the balancer over, look for a counter weight, if it has one then it is for a 400 sbc. John Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted December 11, 2006 Share Posted December 11, 2006 The 400 balancers are scalloped instead of counterweighted, I'm pretty sure, but anyway look for that, the timing marker on the timing cover will hit unless you use the matching timing cover. Quote Link to comment Share on other sites More sharing options...
HICKL Posted December 11, 2006 Author Share Posted December 11, 2006 Thanks guys, I will take a look at it tonight and see if I can tell. Is there particular 350 applications that would use the larger balancer? Is there any advantages or drawbacks to the larger size? Quote Link to comment Share on other sites More sharing options...
Paz8 Posted December 11, 2006 Share Posted December 11, 2006 My 350 SBC has an 8 in. damper pulley, but the damper itself is about 7 in., I took all the pulleys off an 83' Caprice. It's in a ZX so the steering racks not an issue. Quote Link to comment Share on other sites More sharing options...
HICKL Posted December 12, 2006 Author Share Posted December 12, 2006 Ok, here it is, no counter weights but has 3 holes drilled in it. What do you think? http://album.hybridz.org/showphoto.php?photo=12183&cat=704 http://album.hybridz.org/showphoto.php?photo=12184&cat=704 Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted December 12, 2006 Share Posted December 12, 2006 personally ID take it down to the local machine shop and ask THIER opinion and have it bead blasted and mag checked for cracks and painted if it passes, but that APPEARS to be a internal ballanced damper. the timing tab you have probably won,t clear and Id check that the TDC on the damper corrosponds with the true TDC placement , youll need a piston stop and degree wheel to check ( this should print and glue in place for a quick check) http://www.tavia.com/free_degree_wheel.html Quote Link to comment Share on other sites More sharing options...
DavyZ Posted December 12, 2006 Share Posted December 12, 2006 Ok, here it is, no counter weights but has 3 holes drilled in it. What do you think? It looks identical to the one that came on the stock '74 Camaro 350 SBC I bought for my Z. However, if Grumpy says to get it checked, you probably should. Sandblasting it would be a good idea too. Davy Quote Link to comment Share on other sites More sharing options...
HICKL Posted December 12, 2006 Author Share Posted December 12, 2006 If you don't know Grumpy, then I don't trust my local machine shop. I don't think they have 1/4 of your knowledge. Maybe it's best I just scrap it and go find another. Jeff Quote Link to comment Share on other sites More sharing options...
jnjdragracing Posted December 12, 2006 Share Posted December 12, 2006 The balancer in the photo is for a 350 sbc. I called my machine shop and verified it as well. John Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted December 12, 2006 Share Posted December 12, 2006 theres a good chance its fine! but NEVER install ANYTHING thats goint to be spinning thousands of RPMs without being reasonably sure its not going to come flying apart under sudden load changes like shifting at 6000 rpm produce, its not likely to cut your feet off like a flywheel explosion with no scatter shield , but its mighty inconvienent to have the steering develope a mind of its own at 130mph, because shrapnel cut thru your steering linkage SO HAVE it CHECKED/TESTED....at a minimum!! your alternative is expensive but tested to 18,000 rpm and certified http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM%2DB64265&N=700+115&autoview=sku Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted December 12, 2006 Share Posted December 12, 2006 JNJ is correct, that is definately a 350 balancer. Quote Link to comment Share on other sites More sharing options...
HICKL Posted December 12, 2006 Author Share Posted December 12, 2006 Excellent guys, thanks for the help. Hey Grumpy, I work in manufacturing and have a level II in L.P. and Mag particle NDE. Will make sure she's good. Thanks for the advice. I was searching my memory to figure out where I got it from. As it turns out, the timing cover I used on this motor has the tab in the right location for this balancer so they must have gone together. I have parts from a 77 vette 350 laying around as well as and a mid 80's chevy truck 350. Any guess as to which one would have used this large balancer? Quote Link to comment Share on other sites More sharing options...
jnjdragracing Posted December 12, 2006 Share Posted December 12, 2006 I would say the later model truck. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.