nutz4spd
Well-Known Member
I did a compression test and here are the results. (Cylinder #- PSI Reading) 1-160#, 2-175#, 3-160#, 4-180#, 5-165#, 6-161#, 7-164#, 8-150#. It seems to me cylinder 8 has something going on?
Oh hell...
- Thread starter nutz4spd
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At 150psi you will not notice any difference in running. Keep looking.
nutz4spd
Well-Known Member
If the carb were totally out of wack, or in need of a rebuild, would that make the motor knock if it were running too lean?
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Is that "sneezing" through the carb I'm hearing during light revs?
nutz4spd
Well-Known Member
Yes. That is new. Didn't do that before all this started. The carb sat on the shelf for about 3.5 months.
You could do a leak down test. You also could get a bore scope and look at that suspect cylinder. Like I said at one time I will bet you accidentally got something in that motor when the intake was off. Noise, miss, and pulling wires did not change the noise. This tells me there a very good possibility of a nut or washer in the hole. You had better find it now before it really does some damage. Doug DVW that posts here had a issue that could of been a disaster. Crank hangs up after trans overhaul
nutz4spd
Well-Known Member
The hole you're talking about,I'm assuming, is the intake port on the head? I had stuffed paper towels in each intake and exhaust port for that very purpose. To keep crap out. Seems like I'm going to have to pull it back out and tear it down again. Yay me...
Yes hole meaning suspect cylinder. You can buy a bore scope fairly cheap and you could look in each cylinder and see what the piston tops and valves look like. You might see something and then you can at least pin it down to a particular cylinder.
pricer140
Active Member
My ears are bad, however that sounds more like a rattling (loose timing chain) than a knock to me.
OldIron
Member
I hear you knocking. And it sounds like a loose flywheel on the crank to me, being aggravated by an ignition miss.
It's not a rod, but a main can sound like that.
A nut down the intake port would have bent a valve on its way to beating up a piston by now, so it ain't that. But a borescope down the intake runners will confirm that.
Have you put a stethoscope all over the motor and bell housing? That's going to bring a lot of things to light. What does the timing light on each and every cylinder at idle say, and on each rocker arm?
It's not a rod, but a main can sound like that.
A nut down the intake port would have bent a valve on its way to beating up a piston by now, so it ain't that. But a borescope down the intake runners will confirm that.
Have you put a stethoscope all over the motor and bell housing? That's going to bring a lot of things to light. What does the timing light on each and every cylinder at idle say, and on each rocker arm?
nutz4spd
Well-Known Member
I noticed the noise was much more prominent on the back of the intake valley pan. The rocker arms sounded more noisy on the left rear also. I pulled the inspection cover off the bellhousing and watched everything while it was running. Nothing out of the norm. Sound doesn't change when pushing the clutch in either. The noise does increase with rpm and then just about goes away the higher the rims get. Timing is set at about 12 degrees and is steady at idle. The only other indication is the oil pressure will drop from 70 to around 40 and kind of fluctuate some at idle.
nutz4spd
Well-Known Member
I replaced all of the lifters today with oem style ones. Engine is much quiter and the knocking has gone. However, during the break in period it backfired through the exhaust when I would get it up between 2500-3000 rpm. I'm wondering if it has something to do with either the MSD box or the ignition. Not sure how, or if, you can test an MSD box. At this point I'm just grasping at straws.
Just reflecting and remembered that when I rotated the motor on the stand the oil pump shaft slid out/up a little but didn't come out. I'm wondering, is it possible that the gear moved a tooth or two or can it only come out from the bottom?
Just reflecting and remembered that when I rotated the motor on the stand the oil pump shaft slid out/up a little but didn't come out. I'm wondering, is it possible that the gear moved a tooth or two or can it only come out from the bottom?
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