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Old 08-15-2011, 11:41 PM
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383 odd compression reading

Hi everyone I have a 67 camaro with a recently rebuilt 383 stroker
(Trickflow aluminum heads, holley 600cfm,all msd,roller rockers,lunati 60102lk,felpro gaskets), which has been driving me nuts... after sitting it puffs smoke out of right exhaust, on the passenger side of the engine all the plugs are fouled usually, but the other side is perfect, on WOT the engine smokes heavily but is very fast and responsive. On the freeway it doesnt smoke visibly to me, but after running 2500 rpm for an hour the oil pan is nearly empty and oil pressure drops. Compression on the passenger side of the engine goes to 140 and then slowly drops, but the driver side is all perfect. The engine runs rich but excellent and powerful at all times.

Turning in the mixture screws doesnt do anything... Vacuum leak intake gaskets?

Head gasket?

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Old 08-16-2011, 01:02 AM
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I have always thought the rings but I still cant understand why only one side of the engine is messed up.

and what do you mean by no valve seals, like literally or ?
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Old 08-16-2011, 02:11 AM
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If a leak down test is good, it may be nothing more than the wrong intake gasket or it's out of position.

Start w/the simple and work your way in from there. The rings on the bad side could have been installed upside down. BTW, you can bet it's smoking at highway speed, you just aren't able to see it is all. I doubt valve seals could lose that much oil that quickly unless the guides are bad as well.

Non responsive mixture screws could be a vacuum leak (what does it read?) or the transfer slot is over exposed because it doesn't have enough initial timing. What are the timing specs?
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Old 08-16-2011, 02:58 AM
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How many miles? Was it broken in on Mineral or Synthetic oil?
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Old 08-16-2011, 12:00 PM
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it has like 1500 miles at most, and I still use mineral oil since day one. I will do a vacuum test today and post results, as for timing my lights broken so I have to find one. What timing do you guys think I should run it at?
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Old 08-16-2011, 12:27 PM
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Timing

Set up the vacuum gauge and time it with that.

Just slowly keep moving the distributor unitl you have the most vacuum and then maybe back it down just a little from there.

That should get you close to where you want to be.

I would also use the vacuum gauge to set the carb. also.

Just keep turning the jets until you find where it produces the most vacuum.

Jimbo
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Old 08-16-2011, 12:53 PM
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Thanks for the tips... Does this need to be done in Drive or Neutral?
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Old 08-16-2011, 01:00 PM
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Quote:
Originally Posted by 383camaro383
What timing do you guys think I should run it at?
No matter what timing curve/total timing you use- the acid test is whether or not it detonates during the use that you give it and under the conditions it will see. Detonation must be avoided at all costs. It will kill the power as soon as it sets in, plus can damage parts- sometimes severely- if left unchecked.

A starting point for that engine and cam combination could look something like:

12-16 initial timing
12 mechanical advance
32-34(max) total timing
timing all in by no later than about 3000 RPM
vacuum advance adding 10-15

You should verify that what you are seeing at the damper and timing tab for TDC is actually TDC.
DETERMINING TDC will allow you to be sure the timing tab and damper are correctly indicating TDC.

MAKE A TIMING TAPE to see what the total timing is, w/o needing to use a dial back timing light. You can also buy a timing tape, they're not very expensive.

I would caution you about running this engine as-is. If it's using that much oil, park it and get to the bottom of the problem now- before it becomes even more serious!

Good luck.
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Old 08-16-2011, 03:10 PM
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Quote:
Originally Posted by Jimbo17
Set up the vacuum gauge and time it with that.

Just slowly keep moving the distributor unitl you have the most vacuum and then maybe back it down just a little from there.

That should get you close to where you want to be.

I would also use the vacuum gauge to set the carb. also.

Just keep turning the jets until you find where it produces the most vacuum.

Jimbo
Don't do this!!! Its a good way to ruin a good engine, set timing as described in the post by COBALT 327.


Also, with it being an entire bank of cylinders my first guess would be some sort of gasket misalignment. Incorrect ring installation or break in would affect only certain cylinders and some more than others, if it is an entire bank and it is somewhat even I would suspect either a head or intake gasket, or leaking guides on that head. I could be way out in left field on that though.
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Old 08-16-2011, 03:17 PM
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Get a timing light. Don`t even attempt to time it by ear or by vacuum gauge. The timing light is one of the most important pieces a hot rodder can have as it can spell the difference between life and death of your engine.
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Old 08-16-2011, 03:32 PM
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I have one of those chrome penske ones from back in the day and it quit on me the other day. Is there one that you recommend that I can find locally (O'reillys, Autozone)
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Old 08-16-2011, 03:57 PM
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UM, find out why you have poor compression on the passenger side before you try to tune it for more power.

Find out where the oils going, thats a huge amount of oil in a short amount of time.
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