Thread: Chevy Small block cam timing

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I put a summit racing camshaft part # SUM-1103 in a 400sb with 3 way adjustable timing gears set at 0. When starting it, it is difficult and seems like the timing is off. Vacuum is at 15 inHm, but my timing mark is at the top of the balancer and it will stall if try adjust it to the gauge. Checked the distributer timing 4 or 5 times and if moved 1 tooth either way it runs worse. I have 2 options left in adjustment on the gears, I can set it on "A" which advances the cam 2 degrees or "R" which retards it 2 degrees. Question is, without using a degree wheel, which way should I go?

Looks like I'll just have to guess...

Well, not sure on everything because this was some one elses project that I took over but here's what I know.

1978 K5 Blazer, stock rear end (not sure what gear), 32" tires, HT350 trans freshly rebuilt but dont know what converter was used (probably stock stall), 4772 Holley double pumper, vacuum dist, and yes it is plugged to the carbs vac advance port. No vacuum leaks.

I also think my oil is a little too thin, lol. I drained it and used some from the shops pump but I did know they changed it to 0w30. It ran good till it got good and hot and lost power and I noticed that the oil pressure at idle dropped to 5 psi. All the main clearances were right on specs. What do you think of running 20w50, or 40 or 50 weight racing oil? When I had 10w30 in it psi was good but still got down to about 20psi after warm up

I run either Valvoline 10-40 or Mobil 1 Synthetic (for fresh engines) in most everything. Switching to heavy weight or straight weight 40 or 50 racing oil is usually little more then a temporary fix for something wrong internally......

Agreed...If 10W-40 doesn't provide adequate oil pressure, you have other problems...

Should have specified on the synthetic.... I do the initial run in on 10-40 Valvoiline, 30 minutes or so depending on what the cam is, etc. then change the oil and filter. Then run a few hundred miles with 10W-40 to get the rings seated and make sure everything is leak free and working right, then I switch to synthetic.

I will get to work on it again this Saturday so I guess I'm gonna put it back together with the cam at the advanced setting, change the oil to 10W40 Valvoline, and quadruple recheck everything else. The truck is actually 125 miles from where I live so hopefully I'll get to drive it home. If not, I'm bringing the trailer this time and will tow it to the shop so I can really work on the problem.

Reset the timing chain positioned at the advanced setting and then found that this distributor was now off about 2 teeth. Changed the oil and now have better oil pressure but it still is kinda low (10psi in gear at idle but only after driving a while). Other than that, I put about 200 miles on it and it ran great! Might step up to 20W50 on next oil change. Thanks guys

When distributor timing is far advanced, say 30 degrees, the motor cranks hard. On cam timing, go to top dead on #1. Just past top dead, the intake valve should start to open, meaning the valve should be about .050 open, which you can eyeball, close enough for a stock motor, but you should use a dial caliper, especially for a modified motor. From there that should tell you whether to advance or retard the timing on the cam.

not all cam s open past tdc this his to do with the cam size on dur .cam timing is not dist timming .cam timing should be done with a degree wheel and a dial indicator and can be 050 numbers or what the cam grinder use . you could do it other ways but this is the best way but of coarse you need to find true TDC before starting and then you can check TDC on the damper to timming tab is zero before you bolt the head down so what you time the engine you know timming marks are true

what size clearance you have other then right on spec?? rods for oil clearances can be from .001.2 to .003.+ and mains .0007 to .003.+ how were they check ? the stock oil pump is not going to give much oil psi if crank is past .003. on rods and mains. hot oil thins. them are specs for the 350 sbc thats is in spec but thats not mine on a mild drive it every day engine i like to be about in the middle of specs