Reading plugs
- Thread starter grjammer
- Start date
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Start with the basics, are the plugs the correct heat range and gapped properly, check the initial and total timing, vacuum gauge to check carburetor mixture screw adjustment.
Kendog 170
Let the boy go !
Popping out carb or exhaust? Valves adjusted properly?
1) do not read the plugs only 4 mins in. Your still breaking in, assembly lubes burning off, fuel mixtures still off due to warm up cycle not up to temp, if there is a choke, is it set correctly, etc.
2) focus on the popping. Too lean pop, gasket leak from pop or timing? Valve sticking? Double check spark plug wire order. All bad for any engine let alone new one. Buy an air fuel ratio gauge. That’s the bare minimum you need to make sure all is running properly and the air fuel ratio correct.
2) focus on the popping. Too lean pop, gasket leak from pop or timing? Valve sticking? Double check spark plug wire order. All bad for any engine let alone new one. Buy an air fuel ratio gauge. That’s the bare minimum you need to make sure all is running properly and the air fuel ratio correct.
Has the correct plugs and gapped good. timing was not set as I didn't want to run it long. I am tearing the engine down now for what looks like a major rear main seal failure. Popping was like an exhaust backfire. Didn't belch fire out the carb at any time. the one sided dark brown shiny spots on the insulator surprises me, have never seen that. Using a stock coil so isn't from a mega spark.
I couldn't get it to idle and stay running below 1k rpm, but ran smooth above that. I think I'm pulling significant air from somewhere, intake is coming off today after I get it on the stand. Going to check the cam & lifters for anything strange as well. Fingers crossed there.
Seems like a few problems I have to sort out for the next round. Gaskets and sealer on the way, I am getting efficient at pulling this thing out, this is pull number 2. (Bad freeze plug install caused 1st pull).
Hopefully I can run it longer next time.
I couldn't get it to idle and stay running below 1k rpm, but ran smooth above that. I think I'm pulling significant air from somewhere, intake is coming off today after I get it on the stand. Going to check the cam & lifters for anything strange as well. Fingers crossed there.
Seems like a few problems I have to sort out for the next round. Gaskets and sealer on the way, I am getting efficient at pulling this thing out, this is pull number 2. (Bad freeze plug install caused 1st pull).
Hopefully I can run it longer next time.
How do you know it’s the correct plug? Is the engine dead stock? You need to post up what you have and what plug that is.
I can tell you it’s getting oil past the rings and/or guides at idle.
Since it’s new I’m assuming it’s the rings. If this was a fresh engine you need to verify ignition timing pronto.
I'm sure the rings haven't seated yet with the short run time. RC12YC plugs were supplied by 440 source for their stealth heads. I almost have it out and should have it on the stand later today. Going to fix the rear main seal, and remove the intake as well to re-seal and get a look at the cam and lifters. Hopefully I don't see any major issues.
Cam is a Sealed Power CS661. (292/309 110 ICL, 115 LSA) . Degreed about 107 ICL so tweaked it with a gear set to install on 110. Addons are the Stealth heads and Tri-Y's.
Pistons are Speed Pro 350NP, with a compression distance of 1.99. I didn't get an in the hole measurement but last year I figured about 8.5 cr. Hopefully it is enough for a mild cruiser.
Cam is a Sealed Power CS661. (292/309 110 ICL, 115 LSA) . Degreed about 107 ICL so tweaked it with a gear set to install on 110. Addons are the Stealth heads and Tri-Y's.
Pistons are Speed Pro 350NP, with a compression distance of 1.99. I didn't get an in the hole measurement but last year I figured about 8.5 cr. Hopefully it is enough for a mild cruiser.
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Kendog 170
Let the boy go !
I squirt some cam lube while the intakes off.
Well the 12 is right on the edge of being too cold for that CR and your cam.
Please explain your engine break in procedure.
If you did the 20-30 minute cam break in the rings had better be seated.
If it takes 500 miles to get the rings in you might as well pull it now and have someone that knows how to hone a cylinder fix it.
The rings should be in by the time the cam is in.
TT5.9mag
Two atmospheres are better than one
There is zero, I’ll repeat that, ZERO reason to try and gleam any information from a plug on 4 minutes of run time on a new engine. It’s burning off all the **** in the cylinder that’s left during assembly, (IE: oils, dust, etc) and the fueling will be all over the place, AND the timing will be all over the place. There is nothing to learn from the plug.
I agree with more time needed to read the plug, just haven't ever seen such a defined dark brown mark that doesn't rub off.
I have not been satisfied with the initial running behavior to conduct the break in "run-in" of the cam. I will re-lube the cam with some good stuff I have. I used Driven GP-1 gel. I have not really nailed down a procedure for the cam break in other than get it timed run it for 15-20 minutes running rpm's up and down slowly from 2 to 3k.
Engine is now on the stand so will begin pulling it apart tomorrow.
I have not been satisfied with the initial running behavior to conduct the break in "run-in" of the cam. I will re-lube the cam with some good stuff I have. I used Driven GP-1 gel. I have not really nailed down a procedure for the cam break in other than get it timed run it for 15-20 minutes running rpm's up and down slowly from 2 to 3k.
Engine is now on the stand so will begin pulling it apart tomorrow.
TT5.9mag
Two atmospheres are better than one
At no point should you let that engine idle until after the break in. When you start it, immediately bring it up to 3000 rpm and pull in a bunch of timing. Like 40 degrees is not crazy. Do 30 minutes of run time at/around/about 3000rpm. Don’t worry about fuel there is no load on the engine and you won’t hurt it running a little lean or rich. Just get it started, pull in timing and don’t let it idle and keep it cool.
And when it goes flat, the cam company will get thoroughly thrashed and get the full brunt of the blame.
Wow, need to think positive guys, and no, not positive I will wipe the cam. lol
I agree with not letting it idle, and pull in rpm. I have read a lot of cam break in procedures, and find that most every one has the same recommendations of varying rpm. Most of them 20-30 minutes, 2-3k. I won't blame the cam or lifter manufacturer if it does wipe. I will inspect the lifters and lobes to see if there are any indications of non-rotation. I measured the crown of the lifters and cam lobe taper at first assembly. Crown was .0015 to .002, and taper was .0015.
Going to use a new filter and replace the break in oil for the next attempt. Any sure fire recommendations for the oil or additives? They all claim to be best.
I will follow up.
Thanks for the interest, I always appreciate good advice.
I agree with not letting it idle, and pull in rpm. I have read a lot of cam break in procedures, and find that most every one has the same recommendations of varying rpm. Most of them 20-30 minutes, 2-3k. I won't blame the cam or lifter manufacturer if it does wipe. I will inspect the lifters and lobes to see if there are any indications of non-rotation. I measured the crown of the lifters and cam lobe taper at first assembly. Crown was .0015 to .002, and taper was .0015.
Going to use a new filter and replace the break in oil for the next attempt. Any sure fire recommendations for the oil or additives? They all claim to be best.
I will follow up.
Thanks for the interest, I always appreciate good advice.
Buy a break in oil.
Never use additives. If the oil you like needs an additive buy a better oil.
Back in the day cam manufacturers recommended 2000 rpm at steady speed for 20 minutes. get them lifters spinning and keep them spinning at the same rate.
I remember it like yesterday and still use the OLD recommendation.
I remember it like yesterday and still use the OLD recommendation.
All the real cam grinders are long gone and dead, I'll stick with Sig's recommendation from years ago.
Probably what I will do when I fire it up next time. I have 2 lifters that show they aren't spinning. Going to move a spinning lifter into the holes to see if it will spin when rotated by hand. Lobe taper and crown were measured before install. Coincidental that I had two lifters that measured a little shy. .001 to .0015 instead of .0015 to .002. Hopefully only a lifter replacement, but may go roller if I can't get them all spinning. Cam looks good with barely any wear marks yet.
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