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Post a reply to the thread: Measuring +100 Pushrods?
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Did this ever reach a conclusion?
Octane now is far better than 'back in the day' unleaded is 95 octane. Old 5 star was only 98 octane.
If you use super unleaded it's 98 or 102 depending on brand. American fuel is around 92 octane.
at the very least fit a locknut on top of each adjuster nut so they can't back off.
timing settings are fuel dependant too. if you use cheap crappy low octane unleaded with your pop up pistons it'll pink unless the timing's backed off more than 'stock' settings. the 'stock' settings allowed for decent octane fuel that was available in the day (plus your engine's not stock so.......). personally unless using a rolling road i'd go with the back it off until it just doesn't pink method too, that way you're allowing for how the engine is now with the fuel you use now .
I forgot to ask, did you fit new nuts on the rockers? I would suggest you do as this may be why everything had come loose.
You really need to get the engine timing set with a timing light, doing it by ear is not really good enough.
I think with it all set up correctly again you might get all of your power back.
Originally Posted by blackpopracing
...Good news on the increase in power, you might still need to adjust the carburettor to get more power, which may mean you can get more advance without pinking. Do you know what the timing is now you have backed it off to avoid pinking?
I didnt measure it with a rev gun (forgotten what it is called) we just did it by ear.
Drove the car and it was pinking from the off, so stopped adjusted it back a bit, and drove it again etc, until it was only pinking at three quarter throttle.
It needs finishing and dealing back a touch more until it stops pinking completely, but there wasn't time yesterday as it was getting late.
You don't need to put oil down the cylinders - thats just a secondary test if compression is poor to see if its rings or valves. If you add a little oil & compression improves then its rings that are the culprit, if no improvement then its valves.
Ref your way of testing.
I think you did it a bit wrong. If you did not hold the throttle wide open you wont see good compression.
To test properly engine ought to be warm with all plugs removed. Disconnect + side of coil to avoid engine starting. Fix throttle wide open (foot to floor) by wedging something on throttle pedal etc.
Then turn engine on starter for a few turns until whoever is looking at guage sees no further increase in reading - usually 2-3 seconds is enough.
With a V8 you may see a drop on the last few cylinders as the battery will be getting tired.
As I said before, 10% variation across all cylinders is ok, your readings above are not too bad but cylinder 5 is a lot higher which is not a bad thing in itself, but possibly shows the others are not so good.
I would retest again following what is written above and see what the results are.
Good news on the increase in power, you might still need to adjust the carburettor to get more power, which may mean you can get more advance without pinking. Do you know what the timing is now you have backed it off to avoid pinking?
The compression test was run dry on a cold engine and the engine was turned over twice for each cylinder, with the throttle left untouched.
I thought I should mention that as I've read different things about putting oil in the cylinders for a wet test and running the test with the engine warmed up and that you are supposed to turn the engine over 4 times for each cylinder. I didnt know any of that when I ran the test. So that might effect my readings?
Right, I finally managed to get some work done on the car today.
I found that all the pushrods were chewed up from rubbing against the valve guides.
Also many of the rocker arms were rattling loose, and some of the pushrods were not seated in the lifters they had jumped out.
So they were all removed, a mate came over and helped me and we stripped off the rocker arms
and pushrods and fitted the new hardened +100 pushrods and refitted the original 1.5 ratio rocker arms, plus the one I was sent by mygasser.
They were all done following the
1 - 8 - 4 - 3
6 - 5 - 7 - 2
when piston 1 exhaust and valve rods are at rocking point piston 6 rods and rocker arms were adjusted etc...
then when that was all done, we did the compression test with the results as follows:
Piston 1 = 130
Piston 2 = 140
Piston 3 = 130
Piston 4 = 135
Piston 5 = 160
Piston 6 = 130
Piston 7 = 140
Piston 8 = 120
So some degree of variation there, but a mechanic told me that with the age of engine I have thats pretty good and it will still run fine.
Finally we fire it up and tested it. The timing was slightly advanced from what it was previously, and was pinking on a test run, so we retarded it slightly,
at three quarter throttle it started pinking again, so we retarded it a tiny bit more. It still doesnt have the same power that it once did, but it is much much better than it was.
I have to admit that the vast majority of the work was done by my mate, I would never have managed it without his help.
The next thing to do it an oil change and flush the engine then put new oil in and the zink engine break in additive that I was sent by comp cams.
I tried to fit the rev counter, but I had bought a dash mounted one and not a surface mounted one and the wires were not long enough to reach, so that is a job for another time now...
Originally Posted by mygasser
3 rocker arms and 3 pushrods sent out today mate. i'll let you know the postage cost when i do next week.
Thank you, I only needed one of each, but it is handy to have spares.
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