So I just started a 350 completely rebuilt and remachined. All ***embly goop on the cam and prelubed with drill.It has the edelbrck rpm cam,lifter,head,intake,carb(750) package. We ran it up to about 2300 and sounded great initialy.After about 5 minutes it started a slight rattle upper end noise on the p***enger side.Then the noise seemed to start coming from both sides. The headers started glowing red so we backed it down and shut her off. The oil pressure was a constant 75 pounds start to finish. The coolant temp rose to 220 because the electric fan did not kick on but I immediately put a jumper in to manualy run it. The temp dropped very quick to 180. When it cooled I restarted it and checked to see if the mixture needles were seated.They were so I am not hittling power inrichment early. Timing was set at 25 degrees at 2300 with no vacuum ***ist hooked up.And yes on that restart it still rattled at the top end. SO.....did I loose the cam and if so why? .......Why the red headers?
I've run into the dreaded "glowing red headers" when starting up a new engine several times. After an exhausting (haha) search of causes...lean mixture, vacuum leak, timing problem, etc., it usually turns out to be that the lifters were adjusted too tight in the beginning. These were on engines built by shops, not myself. My belief is that a lot of shops use the shop manual to tighten up the valvetrain. These manuals recommend setting the lash to zero and then tighten one more turn...this is almost always WAY too much...I do 1/4 - 3/8 turn more, that's it. And I've never had a problem with misadjusted lifters in hundreds of head replacements on SBC's I used to do at work. Even if they did it only 1/4 to 1/2 turn past zero, it could be that they didn't prelube the lifters correctly. I soak them in oil for about 3-4 days before installing them, which some guys do, but I also use a pushrod, and push down each lifter individually, several times during the oil soak to drive out all air bubbles, and completely fill them with oil. I think this is very important to get it right the first time! To fix this, remove one valve cover at a time and set the valves running. You can buy little clips to slow the oil from shooting out the pushrods/rockers, but it is still a messy job. Loosen the rocker nut until the valve clatters, turn in until it quiets, then tighten 1/4 to 1/2 more. BTW, you wrote that your mixture screws were "seated"? Is that correct? If so, you areprobably running the carb way too lean....turn them out about 2 full turns as a baseline and readjust after bringing the engine to idle, turn them in until you hear the engine stumble, then go 1 1/2 turns back out.
New engines generally run somewhat hotter do to clearances being tighter before everything seats in...Where you running it in a somewhat dark garage?....Thinner gauge headers will turn red, in daylight it isn't seen.....Some Chevy crate engines sound like they were ***embled with marbles....Loose clearances until everything heats up and expands
Instructions with aftermarket performance flat tappet cams say to start the engine,immediately run it up to 2500 rpm and so on.Also says if there's a problem shut down the engine quick,fix it,and rev it up again to continue the break in.So the cam is probably ok as this point. I've always adjusted hydraulic lifter about 3/4 turn preload before starting the engine,never had a problem.I don't think a full turn or so will damage anything at reasonable engines speeds as the lifter internals should have enough travel to deal with it. I adjust the valves using the typical way,watch a particular cylinder,rotate engine until the exhaust valve starts to open,adjust intake.Then rotate until the intake cycles through opening and when it's nearly closed,adjust the exhaust valve.After cam break in and a little more engine time,I check the valve adjustment again,engine not running,I don't like the oil mess. Might be better to do the final adjustment on a running engine however. Top end clatter? Hopefully it's just some loose lifters........
One thing you might want to think about, pretty much all oil now a days doesnt have the amount of zinc to provide the correct lubrication for flat-tappet cam shafts. The government mandated to lower the amount of zinc and the oils work fine in todays roller motors. So do some research,there are additives and other oils available. Once the cam is broke in for a couple thousand miles I think the shelf oil is ok,but not during break-in. And never break in a motor using synthetic,rings wont seat right..Good luck,Dan
All of the above! I've seen too many "factory" rebuilds with too-tight valves. They have a weird shake at idle (on a non-cammed motor) and I usually pick up on it right away. I go with the 1/2 turn myself, you're better off with them a bit looser than risk burning a valve. I'd go with an initial carb setting of cranking in the mixture screws, then 1.5 turns out, it'll run rich enough for the time being. Do the valve adjustment thing, then fine tune the mixture. I use the vacuum gage or I listen to the exhaust while my helper adjusts the mixture screws. Bob
Agree to the Zinc..... I have only had one car ever glow red on initial start, cast iron manifolds, to rich and to little timing. Put fuel into the manifold and it kept burning there. But you do need to check before you rip it before.... couple of rockers come loose?
If you run your mill at a fast idle for any length of time the headers will glow, its common. I never break a cam in much above about 1,200 to 1,500 but I'm not very good at the rules, what else can I say. I would probably adjust the valves and go from there. if it runs alright after you finish your break in you're in there like swim wear and if not then I would worry about the cam being a problem. Overhot is not your best situation, but keep this in mind. Back on the day when the fellas were running chrome rings, it was common for them to block the radiator and make it hot on purpose to help the rings seat. I don't think it helped but a lot of the old timmey racers thought that was the way to do it.
drain the oil...got metal in it? No? then your ok reset the valves and go. I wiped a cam in a huffed S-10 once and there was NO dout it was wiped when the oil was drained
Red hedders are a sign that you need more fans for cam break in. Totally normal on a new engine with just a box fan pointed at the car.
Explain what 25 degress timing at 2300 rpm is, timing for small blocks should be 36 degrees at full advance, depending on springs in the dizzy, what is the initial?
Glowing headers = lean mix or not enough timing. Start with the mixture screws 1.5-2 turns out. At 2300rpm you should be off the idle circuit. Make sure you have at least 30 degrees of total timing. Don't bother checking the oil - the engine is breaking in right now and the oil will be full of metal. Change the filter if you are worried since ***embly grease and cam break in lube can clog the filter pretty quickly. I would let the motor cool, and check the plugs to see what they say. Then retorque everything, change the oil filter, reset the valves with a half turn past zero lash, and fire it up and finish the break in. The edelbrock cams are old school lobes - gentle ramps and forgiving.
Oillevel too high or too hot, which would cause the oil to foam and therefore cause lifters to collapse. Not enough timing. Late ignition means the mixture is still burning hot in the exhaust.
I agree my timing may be a little low...... As to the mixture needle comment I am not refering to the mixture screws but the actual needle and jet ***embly. I checked to make sure there was enough vacuum to hold them down so as not to be dumping too much fuel with out load. We are using Brad Penn Break in oil "the green oil" The coolant temp riefly hit 220 then went down to 180 when we hot wired the electric fan.(small oversite in the wiring missed splice) Gonna check the valves when I get a chance SOON
I agree with the timing causing the red headers. it is amazing to see the fire go out so quickly when adjusting the timing on a motor that is cooking the pipes.
I ran out of time the other night. I won't get a chance to look at this untill the weekend so I was just trying to gather some thoughts to settle down my mind. You HAMBers always have great thoughts! Thanks! By the way... my buddy called Edeldrock and they said.....set initial timing to 16 deg and total timing to 32 deg. Seems low on total timing to me. They also said the poly locks on the roller rockers are common to come loose!???! I will know more soon and I will post an update.
16 deg. initial sounds high to me...more like 10-12.Total around32-38... I run mine @ 10 initial 36-40 total..
Timing kind of depends on the heads too, if you have modern heads with a fast burn type chamber they don't need so much timing. Polylocks...stay tight if you set them properly, but if you just tighten the set screw, and hold the nut still, they can come loose.
Yeah..Ive been schooled 8-12 Initial (disconnected and plugged vac. line) 30-36 Total around 3000 rpm .."all in" Squirrel..do you think 8 innitial, and 32-36 would be ok on a mid 70's era head with 1.95's 1.60's? its a 68 - 327
Thanks Bud I fried my timing light ..so im back to square one with this darn thing.. enjenjoe may stop out and ease my agrivation with this pig.. I think i got it out of wack sorry to the OP for bogarting your thread
Ok School me on the propper way to tighten these things. I adjusted the valves then held the nut in position and tightened down the set screw. I was to look at the car last night to see if the rockers loosened but couldn't coordinate it with my buddy.So it may not be an issue.?.
I was taught to tighten the nut and set screw at the same time. takes some practice to get the set screw at the right place, so that you end up at the correct nut position.
The way I used to do it was to tighten it up exactly where it has to be, loosen it up just a bit ( maybe 1/16 to 1/8 of a turn), tighten the setscrew, then run the nut back to where it was in the first place.
When I use to run locks, I would face off the stud top. Making sure it was flat. Obviously this applies to screw in studs, but the loosening problem will vanish. The set screw can't seat on that uneven ridged top. If your gonna run it hard you might as well pin em or put screw in studs in. Anyway that cured my problem with loosening. Or a stud girdle. Lippy
Bingo. don't over do it though. it is possiple to break the top of the stud off, provided You're a meathead, like me.
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