Spitting back through carburator - Page 2 - Chevelle Tech
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post #16 of 33 (permalink) Old Mar 25th, 19, 11:54 PM
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Justin
 
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This is how I broke mine in. I fired the engine up with the cap off the radiator to get air bubbles out and I had the hose near by. I had a leaf blower blowing directly into the radiator to keep air flow going. Immediately bring the RPMs up to 1500 and hold there and fluctuate between that and 2000. Keep an eye on oil pressure and water temp and get a decent timing advance so it is not running too hot. Helps to have a buddy there for another set of eyes. Make sure to use oil with zinc additive. I used Joe Gibbs break in oil and a comp cams oil additive.
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1974 chevelle with 73 laguna nose sbc 357 Brodix IK180 heads Comp Cams XE274H Edelbrock RPM airgap 650 AED double pumper, M20 muncie, Truetrac with 3.73s
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post #17 of 33 (permalink) Old Mar 26th, 19, 4:15 AM Thread Starter
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Lou
 
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Re: Spitting back through carburator

Quote:
Originally Posted by JF74chevelle View Post
This is how I broke mine in. I fired the engine up with the cap off the radiator to get air bubbles out and I had the hose near by. I had a leaf blower blowing directly into the radiator to keep air flow going. Immediately bring the RPMs up to 1500 and hold there and fluctuate between that and 2000. Keep an eye on oil pressure and water temp and get a decent timing advance so it is not running too hot. Helps to have a buddy there for another set of eyes. Make sure to use oil with zinc additive. I used Joe Gibbs break in oil and a comp cams oil additive.
Hi,

Thanks for the information. I just bought 5 gallons of the Lucas High Zinc Break in oil. I'll drain what I have in there now.
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post #18 of 33 (permalink) Old Mar 26th, 19, 9:21 AM
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Gene
 
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Re: Spitting back through carburator

Disaster narrowly averted!


Hey, I think Harold hit on it,....... the balancer will show TDC TWICE in a full revolution ( these are 4 stroke engines, right).... so its likely you are sitting on #6 TDC ( 360 out). You can verify by popping the drivers side valve cover and eyeballing #1 valves, THEY SHOULD BE CLOSED. I hope you find them hanging open, which means you are at #6. BTW, you can check the degree of the cam while its parked in #6 TDC. You want to see the INTAKE valve slightly more open ( closer to the head surface) than the EXHAUST.

Now, if you find the valves closed on #1,and that is the TDC you were using, then I suspect you have misadjusted valves, and I would have Leo drop by. Its a "feel" thing to set them, esp hydraulics. You'll ahve to go through the whole IO/EC procedure for all 16.

It is convention to have #1 plug post pointed at #1 cylinder, but it really is of no issue.
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post #19 of 33 (permalink) Old Mar 26th, 19, 10:33 AM
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Re: Spitting back through carburator

Be better off and perhaps richer if you take up the offer on the help. If nothing else, just to confirm all is correct.
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post #20 of 33 (permalink) Old Mar 26th, 19, 11:21 AM Thread Starter
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Lou
 
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Re: Spitting back through carburator

I've checked the 180 issue. It's firing on #1. It's the rotor distributor that's out of wack or it's a fuel issue.

I checked the #1 piston by using the simple method of putting a rag or finger or thumb over the hole as per the 1964 Chevelle Shop manual. The timing mark on the balancer comes up on the timing plate on the engine on the firing stroke. It also lights up on the #6 during the first revolution. I've also checked it with the valve covers off and you get wiggle on the rockers at TDC.

Holy Crap I can't believe it. I hate to admit it but I just rechecked the cylinder numbering system.
Boy do I feel stupid. I've got the plug wires all screwed up. So sorry to bother everybody. I'm sure it will crank up now. But I have to wait for my special break in oil before I can try it again. Crap. Well, all I can say is I'm glad I posted this question since I found out about the break in of cams and flat lifters. So maybe it was meant to be to save me from disaster. Thanks to everyone for their help.

Lou
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post #21 of 33 (permalink) Old Mar 26th, 19, 2:08 PM
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Justin
 
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Good luck and keep us posted on how it goes.
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1974 chevelle with 73 laguna nose sbc 357 Brodix IK180 heads Comp Cams XE274H Edelbrock RPM airgap 650 AED double pumper, M20 muncie, Truetrac with 3.73s
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post #22 of 33 (permalink) Old Mar 26th, 19, 10:00 PM
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Re: Spitting back through carburator

Lou, I live less than an hour away and today's oil is fine, BillK advised me to use Mobil 1 10W30 from the beginning and after getting the engine warm and setting the specs, take it for a drive. Just an FYI
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post #23 of 33 (permalink) Old Mar 27th, 19, 8:34 AM
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Re: Spitting back through carburator

Glad you figured it out. Next; tell us how great itís running!
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post #24 of 33 (permalink) Old Mar 28th, 19, 8:57 AM Thread Starter
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Lou
 
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Re: Spitting back through carburator

Here's a link to a good article on oils and cam break in. I'm still waiting for my oil which I had to special order since no one carried the Lucas brand locally. As you can see from the article Lucas has the highest concentrations of zinc. Apparently this issue regarding cam lobe wear at break in has been around for a while. Don't know why I missed it. Should be plastered in big letters on billboards across the country.

https://www.hotrod.com/articles/ccrp...reak-in-guide/


Lou
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post #25 of 33 (permalink) Old Mar 28th, 19, 10:06 AM Thread Starter
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Lou
 
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Re: Spitting back through carburator

Here's a good pdf on the procedure to break in the cam.
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File Type: pdf Camshaft-Break-In-Proced-Rev4-12-07.pdf (29.9 KB, 10 views)
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post #26 of 33 (permalink) Old Mar 28th, 19, 12:45 PM
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Re: Spitting back through carburator

Quote:
Originally Posted by 1943MB View Post
Here's a link to a good article on oils and cam break in. I'm still waiting for my oil which I had to special order since no one carried the Lucas brand locally. As you can see from the article Lucas has the highest concentrations of zinc. Apparently this issue regarding cam lobe wear at break in has been around for a while. Don't know why I missed it. Should be plastered in big letters on billboards across the country.

https://www.hotrod.com/articles/ccrp...reak-in-guide/


Lou
I use lucas and couldn't be happier.
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post #27 of 33 (permalink) Old Mar 28th, 19, 12:56 PM
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Re: Spitting back through carburator

Quote:
Originally Posted by JF74chevelle View Post
Did you break in the cam if itís a flat tappet? Theyíll go flat and and have symptoms like this if a lobe is gone.
I disagree, to a point... While a flat lobe could cause similar symptoms, there still could be other culprets, such as a broken valve spring or valves too time, timing, firing order, etc...

But I disagree with the "flat cam" assessment. The cam may be junk now, true, but IMO, if the motor has yet to fire, I doubt its cranked enough to flatten a lobe to the point of running bad... Now IF it had been running for 5-10 minutes or more, even just a low idle, then sure, more likely a wiped cam lobe...
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post #28 of 33 (permalink) Old Mar 28th, 19, 3:39 PM Thread Starter
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Re: Spitting back through carburator

I am no expert on cam manufacture but it was very surprising to me to see that a cam lobe pressing on a spring loaded lifter is going to go flat. And that's even if it doesn't get any oil. Both those surfaces are supposed to be in constant contact and if the metal is smooth as glass, which it should be, then the steel used on the end of the lobes of cams today is not as hard as the cams of old. And, it would appear the lifters made today have a surface that's harder than the lobes of the cam since I did not read that you hollow out the flat lifters. Or maybe you do both ? IMHO the only reason the cams today last as long as they do is thanks to rollers. Either in the cam or in the lifters. I think it's just something they took nickel out of to save money. That's not a scientific fact and I have no proof but when it comes to ways of saving money the auto industry is up there. So how about they concoct this business about using special oil. Running the engine up when you start it to get oil on the lifters. And what ? After I splash oil all over my cam and lifters for 20 minutes the cam gets majically super hard and I can idle it all day without a worry. How about when I start the engine. Do I have to rev it up everytime to splash oil on the lifters. I don't understand how my cam is so much better after I rev it and splash oil with zinc in it. Is the what morph's the cam into something other than what it was when it was installed. Sounds like the best option if putting in a new cam is to discard the flat tappets and use rollers because the cams today can't handle flat tappets.
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post #29 of 33 (permalink) Old Mar 28th, 19, 10:33 PM
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Re: Spitting back through carburator

it's because of lubrication, the all important item in engine life, and running the engine at 1500-2000 rpm for 15 or 20 minutes gets everything up to operating temp as well.
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post #30 of 33 (permalink) Old Mar 29th, 19, 9:19 AM Thread Starter
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Lou
 
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Re: Spitting back through carburator

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it's because of lubrication, the all important item in engine life, and running the engine at 1500-2000 rpm for 15 or 20 minutes gets everything up to operating temp as well.
Everybody knows you need oil to keep parts from causing friction which generates heat and wear.

There's too much talk about cams loosing their lobes. A cam that looses it's lobe because it's not getting oil is an inferior cam. The cam and lobes are always being submerged in oil at idle. You don't need to rev the engine to coat those surfaces with oil.

The instructions say that the reason you rev the engine is to get the lifter and the cam lobe to seat themselves. What they really mean to say is that the two surfaces are so rough that if it is run at a low RPM at intial startup due to the rougness and softer metals being used you can literally grind the cam down and that spinning the cam at higher RPM helps to smooth out those imperfections,hopefully, and prevent the sandpaper effect. Certainly sounds better to just say they need to seat themselves and get plenty of oil on the two surfaces than to say the cams are inferior in quality and the best way to insure longer life is to smooth out the surfaces at startup. Hense the caveat that if you did not spin out those imperfections at start up your cam will wear out fast and we don't take responsibility for it since you did not follow instructions. It's all a bunch of BS. That cam lobe and lifter surface should be the two hardest and smoothest surfaces in that engine. Abrams tank barrel hard. Show me where GM spent 20 minutes per car revving engines to break in cams.

Lou

Last edited by 1943MB; Mar 29th, 19 at 9:40 AM.
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