How do you initially time a BB before startup?
 

Hey OSO,
Sorry if there is a thread about this question already but I am new to the boating world (2 yrs) just bought a newly rebuild 540ci BB which I'm about to have put on the dyno, but before I do, I need to know how to set timing before I install the distributor. I need to know where distributor needs to be pointing and where TDC is etc. Thanks in advance.

fixx
 

dont know how everyone else does it but i will set the timing on the harmonic ballancer to 8* btdc then line up the rotor with #1 cylinder...you will have to mark the side of the dis with a paint stick or marker where the #1 is on the cap..

Yes I think I remember that part. I just forget which marking is 8*. each notch is 2? If I'm not mistaken? Clockwise correct?

you should not simply assume your balancer marks and pointer are correct. use a positive stop method to identify top dead center on the balancer and pointer as they exist. then measure the circumfrence of the balancer using a narrow tape, divide that number by 360 and thats the radial distance per degree...multiply that number by the number of degrees you want marks for and mark ( or confirm) your balancer appropriately. they sell timing tapes for this at your local speed shop but knowing your tdc mark and pointer are correct is critical at this point.

That's exactly what I needed. Thanks so much for your input.

You might want to pump some oil through the motor prior to dropping the distributor in. And make sure the motor is on number 1 not 6.

fixx
 

If you really want to get that technical!!....if you really want to get into it then you need to remove the cylinder head and put a dial indication the top of the piston,,first install a degree wheel,next try and find top dead center by eye,next put your breaker bar and the rite size socket and move the crankshaft clockwise and counter clockwise or until you find TDC next put the timing pointer at zero on your degree wheel,now compare the timing pointer on the harmonic ballancer,if its off any * your going to have to adjust it to zero..next if you have advanced timing marks on your ballancer then great,now compare the timing marks on the ballancer with the degree wheel,if their off then your going to have to mark the ballancer and put your own * on it..if you have no marks what so ever thenyou can cut your own in with a dremil and the tiny cutoff wheel blade but go lite..i mark them @ 26* to 36*...2* increments.

I don't want to take the head off. I will however make marks like you stated. I think it's a good idea. Thanks.

and there is no need. the positive stop method is the best way even with the head off. it eliminates any question of piston dwell at tdc. you simply " stop" the piston some small amount before TDC with the stop, mark the pulley and wind the motor backwards to the stop and mark the pulley. the center point between the two marks is TDC +/- 0

Motor is going on the dyno in 2 weeks. I will do exactly as you stated before startup and throw a light on it after we get it fired up. You think 8* initial is good for BB?

I'm going to be running either a volt max or msd box. What would timing be at wot or peak hp? If I'm saying this wrong by all means please correct me.

no, start it a little retarded. 4 deg or so. rev motor. chech how much advance you actually have. then time it up to where you want it.

if he wasent confused before,im sure he is now,he just wants to set initial timing before initial startup.as he stated,the engine is going for dyno tuning.:party-smiley-004:

if you are unsure how to set initial timing,let the dyno operator do it,he will no dobt check it anyway before he starts it.

simplest method is if it cough or pops or doesnt start, you arent even close. loosen it up, turn the dist. a little, try and start again. after a couple tries the motor will fire right up, get your timing light out and set it. 5 minutes..... :lolhit:

This is going to be determined by where it runs best on the dyno. Probably somewhere between 32* and 38*. Setting at 8* for intiatially starting it will be fine. The total timing at wot or actually above 3000rpm's is whats going to be important. That's where they will be determining it at. Where it ends up being during idleing isn't that critical. If it is too far off at idle then they will make a correction in the distributor advance curve.

Piston stop and timing tape is what I used when mine went back together. It's really the only way to know for sure that you are shooting the right number. And plus the timing tape shows up a lot better when shooting total.

not as confused as he would be if it has a mismatched front cover pointer and balancer and the marks are wrong by 20 degrees...

i know its a new concept for you to do the basics correctly first rather than fix the failures later but ponder on it and it some and will come to you, i'm sure.

All your information is very helpful and now I completely understand exactly what to do. I really appreciate all your help and I will post dyno numbers and try to get a picture of the sheet up. Should be within 2 weeks. Thanks again everyone!

one thing i am sure of is that u r a rude azz hole and that will never change,just the fact that the op was looking for advice on initial timing sais he does not fully understand the concept,and u have no idea of my capabilities,or what i know,but as usual,u try to insult me,your jelousy shows brightly,but your comment shows that u r not to bright,carry on with your ignorance,it is what we have come to expect from you,:whistle:

fixx
 

hey mike look where he is from,lol,that should tell you his education level..look at the bright side,,we have access to all the cool s h i t and he has to go diving for it..

ya,i think he may have toasted his brain:bong:or maybe sucked in some salt water:lolhit:

I'm not certain I would be telling the guy that 100% accurately explained how to locate perfect TDC with cylinder heads on, which is realistically one of the most crucial steps in putting it together that he has a toaster for a brain. It's not rocket science, it's the proper way to do it. I've been using it for years degreeing cams on DOHC cars instead of just relying on the factory marks, and guess what, alot of times they're off a degree or at least enough room for error that interpretation could go either way.

I honestly think he stated the steps pretty straight forward and easy to follow.

To offset praising him now I will indicate that the left side of his family tree looks more like a bush.... I'd rather have everybody hate me instead of just a few

fixx
 

me personally would rather have the heads off instead of a piece of metal slamming into the top of a piston,,have you ever seen one ofe the sparkplug hole tdc locator in action?? well they flex out of shape when it come in contact with the piston and will throw off the 360* to 359*.and put a mark in the top of the piston,no thankyou.i understand what he is saying but if you read the whole post from the beginning you will see why im all over this..the main ? was asked washe drew first blood....

a piston stop on a bbc is shakey at best,as mrfixx said,they easily bend and even break off,the engine builder should have done that with a posative stop with head off during the build,thats how i have done it for years.the op did not want a lesson on piston stops,he just wanted to know how to initial time a bbc.nothing against the op,but if he was unsure how to initial time it,do you think he should be putting a piston stop in a spark plug hole.as usual steve attempts to insult me,HE DREW FIRST BLOOD.if u look back at some of his previous posts,u will see a pattern of rudeness and attempts of insults,i have his number,no worry what he sais,i have been doing this for almost 40 years.:party-smiley-048:

Yes, I've used them many times on various engine builds. I've never had it not be right and use that technique for degreeing cams on every build I've done. I also never tried to turn the motor over with a 3' breaker bar into it. All it needs is first contact, a 3/8" ratchet with all the plugs out is more then adequate at that point.

I will give the caveat though that I am not a marine engine builder lol, I always built high performance over head cam turbo motors, which requires the cylinder head to be on there considering the cam or cams are up there.

Degree'ing an assembled motor isn't rocket science, quite easy imho. I'm also a big fan of do it right the first time, and while marking TDC while the heads are off by utilizing a dial indicator is another way to do it, when the OP says he has an assembled motor I think it's moving backwards even mentioning pulling the heads to do it.

:bunnydance: I only added that because it's one of the coolest emoticons ever imho

KYAIN
let me start by saying welcome aboard,lots of knowledgeable people on oso,i dont know anything about stevexm,s family tree,and i have no intension of insulting his family,but i think he is the most rude individual i have ever dealt with on oso,and just to clarify,i didn,t say he has a toaster for a brain,i did say i think he has toasted his brain,buy the way,do you know steve,or did you just feel like this should be your first post?

I'm just bored lol... never met the guy and only halfway paying attention to anything other then Manning completing near 50% of his passes to Atlanta

I've actually been around here for awhile, just lingered and finally registered. But it did seem quite odd to see a straightforward, easy to do approach getting blasted when I still feel he did give the best advice given the circumstances the OP posted.

You're right on the toaster thing.. I misread it... eitherway I'll still stick with it to offend all equally. I don't want anybody to feel left out. We've struggled too hard for equality in this country for me to only be a dick part of the time

the op stated that he has a newly rebuilt 540,i must assume that the builder had the heads off,unless he rebuilt it with a can of spray paint,do u get my drift,when i rebuild,i instaii the #1 piston,then install the cam,then find tdc,then i install a flexplate on the crank,and mark it with a pointer,now i can find tdc at any time during and after the build,but what do i know.bye the way,this is one of my favorites.:7160:

easy and straight foreward for someone who has done it a few times,but intiminating for someone who has no knoledge of engine building.also,i would pull the head any day before sticking a piston stop in a newly built [and tight]bbc,that is the proper way imo.and in closing,no future in being a dick,imo.

http://i497.photobucket.com/albums/r...ps461c7f66.png
http://i497.photobucket.com/albums/r...psfa9a3370.png

Just a quick pic of the motor and my boat its going in. scheduled for dyno in 2 weeks. I will let you guys know how it goes.

tommy,boat and engine look good,im sure it will be nice when it is done.

Thanks Mike.. Im dropping it off wednesday to be setup on the dyno and come back friday to make some pulls. I'll post dyno sheet and numbers when I get back. Hope to make between 650 & 700. Keeping fingers crossed.

Hey Fellas, here is a couple videos of the dyno. Motor made 625hp and 676 tq.
http://i497.photobucket.com/albums/r...h_IMG_0764.jpg
http://i497.photobucket.com/albums/r...h_IMG_0762.jpg

tommy,what heads are on your engine?

The heads are iron, world (grumpy jennings)