I will post more about this project once i have time, full track build 260z with a 350 SBC swap.
Below video is my result after installing a rebuilt engine with all new parts, checked timing about 5 times now so I am sure that is not it anymore.
One suspect part is the carb which came with the motor, new Holley 600 CFM on the way though.
I am new to SBCs so if you guys have any clues or tips it will be much appreciated.
https://drive.google.com/open?id=1dTFxvjNRoSn0ZDsXSj1kZKE-sqN3tm3z
You need fuel, spark at the right time and compression. Sounded like it might go but the uneven cranking would lead me to compression. How did you adjust the valves? solid or hydraulic lifters. On a new build it is very easy to over tighten the valves and leave them hanging open, since no compression.
If they are hydraulic lifters simple step would be to turn each cylinder so the lifters are on the base circle of the cam and back the adjusters out until the rockers are a bit loose. This will create a noisy valve train but the valves will seal. Then adjust the valves with the engine running.
Sounds retarded.
HAHAHAHAA.
No, seriously. I don't think you have it timed properly. Try advancing the distributor a bit. I'm assuming HEI? You set the timing at about 10° and have the reluctor bits pointing at each other? Did you check to see if the harmonic balance is actually correct (the outer ring hasn't slipped/moved)?
Have you tried squirting gas down the carb? My first instinct on hearing it start to catch would be floor the gas pedal.
180 out on the distributor?
I'm with dusterbd. Sounds like you set the distributor when the #1 piston was at TDC on the exhaust stroke not the compression stroke.
In reply to NOT A TA :
agree.. check timing and distributor.
Dusterbd13 said:180 out on the distributor?
That was my guess/hope. Wouldn’t hurt to check!
First thing i would do is spray some starting fluid at it and see if it fires up that way. If it doesn't, then i'd dig into the timing some more. Compression and cranking speed sound good to me, so if it's not a lack of fuel then it basically has to be timing.
And for Grips sake remember it is "SOME" starting fluid not "THE SUM OF ALL" starting fluid. You aren't filling the crankcase with the stuff, only a little for the cylinders to make a poppy poppy boom boom reaction.
pull no.1 plug pull that Valve cover, spend 20 min. to be sure, also is the balancer from that engine, there are 3 diff. timing marks through the years, and as said they can slip but not often. just check it you can be done before finishing this thread, or before I can type it.
Fueled by Caffeine said:In reply to NOT A TA :
agree.. check timing and distributor.
Also if the distributor isant properly bolted in etc it can move on its own and advance etc the timing on its own. A guy this past season at Castrol raceway had this problem one night with his dirt late model.
HI all,
Thanks a lot for the helpful advice.
Just to clear up some questions:
I verified timing mark by lining up the crank gear and came gear at 12'.
At that point I insured that both valves were closed and the piston was all the way up.
I tried swapping the distributor 180 and immediately got a backfire out of the carb.
Distributor is a new HEI unit with clear cap and rotor and Pertronix coil
Lifters were set to no lash +1/4 turn using the EO/IC
pulled #4 and #3 plugs both had soot on them, pulled #1 plug and no soot but It is getting spark.
I did try a little starting fluid but I am guy shy with it.
New Holley came in today so tomorrow I will be putting that on and trying some more advance at the distributor.
My last resort is the pull the headers and do a leak down on each cylinder.
You’re getting spark but is it a really good spark or just enough to ignite here and there?
Ive seen quite a few engines get misdiagnosed as having spark because it DID, just not strong enough.
In reply to Twisted46 :
A quarter turn past zero lash might not let the valves close tightly. On SBCs I tightened the nut with my left hand while I pinched and spun the pushrod between my right thumb and index finger. I set them so I could still spin the pushrod.
Twisted46 said:HI all,
Thanks a lot for the helpful advice.
Just to clear up some questions:
I verified timing mark by lining up the crank gear and came gear at 12'.
At that point I insured that both valves were closed and the piston was all the way up.
I tried swapping the distributor 180 and immediately got a backfire out of the carb.
Distributor is a new HEI unit with clear cap and rotor and Pertronix coil
Lifters were set to no lash +1/4 turn using the EO/IC
pulled #4 and #3 plugs both had soot on them, pulled #1 plug and no soot but It is getting spark.
I did try a little starting fluid but I am guy shy with it.
New Holley came in today so tomorrow I will be putting that on and trying some more advance at the distributor.
My last resort is the pull the headers and do a leak down on each cylinder.
Have you done an old fashioned compression test? That would save a lot of work pulling headers.. If you aren't getting much compression that would point to over adjusted valves.
I think you should get comfortable with fire! Not comfortable watching the car burn down but comfortable enough to know that a small fire in a piece of metal is not a large fire in a pile of tinder. Starter fluid is not going to damage your car or burn your garage down unless you freak out and run off if it does somehow cause a fire. I've caught entire fuel tanks full of gasoline on fire and just dealt with it. Not freaking out is the big thing.
Anyway, on an SBC if both the cam and crank timing gear marks are at 12 oc clock, it IS 180 out. They need to be pointing at each other, so crank at 12 and cam at 6 when the distributor is pointing at #1. If you set the distributor with both marks at 12, then the distributor is 180 out.
In reply to Twisted46 :
Okay guys new Holley installed, distributor timing checked again, dedicated ignition wire ran to the distributor and starter fluid used. Still getting the same thing and i have 100 to 110 psi in cylinders 3,4,5,6. I really don't know what else to do.
Spark is pale blue
Put a timing light on #1 and crank it. See where the spark is timing wise. Also make sure you're not 180 out on the dizzy, if that is possible with that motor. I'm not a SBC guy.
Yeah, i'd do the timing light as well. That's the final word on whether the spark timing is right (at least to #1). 100psi compression is poor but it's not enough to not start even with starter fluid.
What are compression numbers in 1,2,7,8?
Also, pull the valve covers and have someone crank it over while you watch the valves and timing light on number 1. Make sure valves are closed at spark event.
Vigo said:Anyway, on an SBC if both the cam and crank timing gear marks are at 12 oc clock, it IS 180 out. They need to be pointing at each other, so crank at 12 and cam at 6 when the distributor is pointing at #1. If you set the distributor with both marks at 12, then the distributor is 180 out.
That would just be tdc of exhaust instead of compression. Give the crank one revolution, and the marks will line up (1 turn of the crank is half a turn at the cam). But once they line up, rotor should be pointing AT #1.
I, too, am also curious about the other cylinder's compression.
And check the firing order. 1 8 4 3 6 5 7 2
Cylinders are numbered:
-- 2 4 6 8
<<<<<
1 3 5 7 --
And I'll third (or am I fourth now?) to put a timing light on it while you crank.
Dusterbd13 said:What are compression numbers in 1,2,7,8?
Also, pull the valve covers and have someone crank it over while you watch the valves and timing light on number 1. Make sure valves are closed at spark event.
That was gonna be my next suggestion after confirming spark at #1 sometime around 10 degrees BTDC.
Well I found something interesting that may be the issue.
While trying the timing light out I couldn't get it to work reliably while cranking.
I have my ignition on a switch right now and the TL would light when the spark would fire without cranking (I hope that makes sense).
That is also how I previously tested spark color.
While cranking the TL would not light regularly and sometime not for 5-7 revolutions, tried on several wires.
I then pulled the #1 wire again and grounded a plug while I cranked and only saw one pathetic little spark.
watching inside my clear cap while cranking i also couldn't see any any spark most of the time.
Again if i am not cranking and short the ignition wire i get nice hot spark to that plug and TL works as it should
Wire to the distributor is a 12G fused switch right now.
I get battery voltage of 12.7 at rest and about 11 while cranking.
All distributor parts are brand new.
I am now wondering if it is a battery (which i have charged 3-4 times during this process) issue.
You have an ignition problem. We're making progress. How about you tell us what ignition system this thing has.
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