Well, i'll ask the dumb questions cause I'm not the PROfessional engine builder. You said it was all new Did you do the cam break in at recommended rpm and if so did the valve lash change- just asking . I was told that there is no lifters being made in the U.S. any more.
Thanks tinnman, I am familiar with your work and we have mutual friends. Compression test done. 180on each except 3.5.7 dead with 0. Pulled valve cover and valves have good movement. Squited some oil in and no change. As far as admitting a weekness to fellow hot rodders. If I had all the answers it wouldn't be a hobby.
Finally a compression test ! Banished is the mysticism. 3,5,7 dead is a problem. You can bring those cylinders to TDC and apply air to the cylinder and listen for the escape route. Check the rockers. If you hear it exit thru - Intake means intake valves Exhaust means exhaust valves Crankcase means leaking past the rings for various reasons Radiator means head gasket or cracks. My first guess is the valves aren't adjusted as in too tight Second guess isn't so pretty
Thanks for the update. How long ago did you see it run? 3 cylinders with zero compression, on a fresh rebuild that has ran is peculiar. The list gets shorter. Valve seats Rings Head gasket Of course there are other possibilities but being 3,5,7, wouldn't head gasket be most probable? Then again, the zero compression is strange. Someone on here smarter than me will know. It is difficult not standing there.
See its methods not mysticism. I wouldn't call it a weakness but you did tell us a whole bunch of times that your compression was good. That mis information gets the "Zebra" hunt going. Glad we are this far now- holy crap!!!! Now that you have a direction, its easy (er) to track down the cause. You said in an earlier post that you have vortec heads, I don't recall seeing the cam specs. Vortec heads are limited on the amount of valve lift they can handle. You can easily bind them up and bend valves or pull the studs out of the heads.
My Apologies!! I,m the a-hole that asked if you were pulling our legs,Your frustrated and were frustrated trying to help thru a computer,there are guys on here that know more about cars than God!! You will get to know their name and you'll be damn sure they have a answer!! F&J asked about compression on 11/18 today is 11/30 you were not listening!! Someone had to give you a Gibbs head slap(NCIS) to clear your head!(not me you would kick my ass)It was tough love! I have bin doing this as a hobby for 45 years and I'm dumber than a stump when it comes to this site and all the knowledge! Glad you made headway and I hope its an easy fix!! Hang in there!! Pete
Now were on the right hunt!! Hopefully its just lifter pump up like I mentioned way back in the thread, the other possabilities arent so nice to have to fix.... Still odd though is that it wouldnt start and run on 5 cylinders.....
With all of the plugs removed and #5 at top dead center on compression, if you put air in #5 and it comes out of the spark plug holes for #3 and #7, the head gasket is leaking between those cylinders. That would screw up intake vacuum and keep the engine from starting. You could leave those 3 spark plugs out and try to start it and see if you get any reaction. 180 pounds is pretty high cranking compression. You might have a high compression engine and head gasket failure is a good possibility. Your ignition system could also have failed causing the spark plug to fire too far before top dead center causing extreme cylinder pressure that could lead to head gasket failure. I built a 301 with 12.5:1 compression and the Fel Pro Blue head gaskets would not hold up. Factory steel gaskets did work. Other racers have also had gasket problems. I've seen an engine with one 20 lap race on it where the head gasket failed and it looked like a torch had cut a notch between the cylinders. Some builders started using steel rings set in grooves cut into the block like many Diesel engines use.
It's a blown head gasket. The parts of the puzzle started coming together. The reason I didn't catch it on the other compression test is I half a$$ed it and checked a couple at random, unfortunately none of them were 3,5,7. After the test I knew what it was because when I was pulling the plugs I got my finger cut by a sharp edge several times getting to the plug covered by the header. I thought it was the header flange or something else. Turns out it is a piece of the head gasket sticking out. That in itself is strange, given the situation it should be blown out between cylinders and odds are it is. Guess I'll find out when I pull the head. The compression is only 9.7-1 with the head gasket. I must have been losing the gasket and dropping cylinders when it suddenly became hard to keep it idling. Still doesn't explain the crazy tach but who cares. Thanks to everyone who provided constructive input.
Well thats not too bad of a fix, I was thinking of far worse things to have to fix. Strange though...no coolant loss??
Ahhh! More mysticism banished by better methods. 180 cranking compression is pretty damn good. My SBC has a calculated compression ratio of 10.4:1 with a 262 cam and has cranking compression in the 180s. Your 383 has a lot more swept volume than my boat anchor and off the top of my head I'm not sure how the ci difference would effect cylinder pressure without knowing the cam specs.
No coolant in the oil or in the cylinders. That makes no sense but I'll see why when I pull the head. I'm just glad it's nothing major.
I'll have to check and get back to you. It's a Comp Cams extreme energy. I think it's something like a H268 and it has 1.6 rockers instead of the 1.5's.
Ok guys...pant pant pant...I just got in. Sorry I'm late, but I'm here to help! Hey...............where is everybody? Hello? Seriously, S74...I learned a couple things here. So if it's any consolation at all, your trials weren't a total waste of time and effort. Thanks.
Next time when 31Vicky starts typing, I'm going to remove my fingers from the keyboard and get me a edg-E-cation . Hope all goes well for you from her on Shaner
I believe you still have a problem. I know a SBC will run with a blown head gasket. It should try and start if not run poorly. It should pop and fart at least. You said it did not do anything. ????? It may not turn over if it gets hydraulic lock from coolant, but if it spins it should fire even with a blown head gasket. Also, need to find out why the head gasket blew. My cousin coming from Texas made three states with a blown head-gasket. I fixed it and he went back the next week without a hitch.
That 477 lift with 1.6 rockers put you over the vortec lift capability with out some work to the heads and beehive springs. Hopefully this is a non issue and everything has been altered accordingly. There may still be a problem, but there's no sense in fixing anything or chasing anything with no compression on 3 (3,5,7) cylinders. I can't see it starting and would guess it should at least fart but I'm not there. The intake vacuum would be a mess and damn near impossible if 3,5,7 were open to each other though.
An engine will run if the gasket between 2 cylinders is blown but if it gets to three cylinders connected together it will make it very difficult to start as compression is pushed back through the intake valve. I agree that it should at least pop back. That's why I suggested that the ignition system might have failed and caused the head gasket to fail. I'd try a points distributor in it as it's easier to troubleshoot. Also, make sure the compression tester still woks by trying it in a cylinder that showed compression before. Sometimes a piece of carbon gets into the valve.
Another thing to remember is that this is a new build and install so that puts it into shake down mode. There could be multiple problems and they may or may not be related to each other. It can display symptoms from multiple problems and when trying to figure it out one needs to keep that in mind. Really in this particular thread there is absolutely nothing concrete to begin to form an opinion on the problem. It's gone from fuel, to ignition, to timing, to 180 out to mechanical failure. Now as engine man points out the most recent compression test could be skewed and should be repeated. As far as I'm concerned and my general Method of Operation - always begin with a compression test, second step is timing mark verification with a piston stop test. If OP shaner had done so, this thread would be much different. Doing this FIRST eliminates soooo many time consuming diagnostic goose chases.
Before tearing into anything I'm going to run the compression again and if the results are the same I was will back off the rockers on all three cylinders to close the valves and do a leak down test.
Generally flogging is for a certain number of strikes according to the crime. He's had enough for now.
What you have never ever had a stumper ? I find it hard to believe that you have correctly diagnosed and immediately fixed every car you've ever worked on.
Been raking my brain here trying to remember problems from the past. I did this at the race track one time. Fellow racer (competitor) had a car that would idle well and then go to shit once he accelerated on the track (circle track). They would come in and re-time and repeat. Came over to use my degree-able timing light. I went over and timed the car and with the timing light on it rev-ed it and the timing moved. Big cap HEI. I told him to pop the cap and after he did that I grabbed the rotor and spun it around and around. I turned rather stiff not easily. Gave it a yank and pulled the rotor and about a inch of shaft out of the distributor. No reason for it to break at that location, but it did. I have never seen the gear pin break, but that could be spinning also. Also, bare with me, its been a while, but I believe you have some compression with a blown head gasket. At least 5-10 psi. Take the rockers off and see it the cylinders hold air. I'll keep trying to think of things I have come across. But I am getting older and some things are going bye, bye... cb1
Immediately, no. Sometimes I do have to think and it's not a matter of just laying on of the hands. There is some really goofy stuff that comes around. Correctly, in my adult life yes, every one I've ever worked on so far. This pertains to no start, no crank, drivability, cooling and electrical issues. Tuning is a trial and error dance but in the end they are correct. Today is another day and this may change. Internal transmissions is not my bag. I lost my dad last year around this time. But you could check my profile and see where this comes from. Not perfect and I probably have made a few mistakes that my dad didnt make, if you learn from them and don't make them twice this stuff gets pretty easy- especially this old shit. He taught me well and from his mistakes so maybe my "we've" comment was out of line a tad. If a guy starts this shit at age 8 its not any different for a guy who starts at 38. I forget that sometimes.
hurry up chop chop get jiggie wit it... J/K inquiring minds wanna know... take yer time do it right....
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