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***327

3K views 22 replies 4 participants last post by  cobalt327 
#1 ·
Hello everyone. Me, Andy and Cory, my brother. We share the duties of keeping a 327 running for daily transportation. We have a small garage behind my house here in Hickory, NC. This problem 327 is in a 63 C10, 3 speed. My questions are, what should my idle timing be? I have engine at 820 rpms, manifold vac is steady at 15, holley 600 vac port capped, has a HEI, 350 heads and headers turbo mufflers.
I read on others threads anywhere from 8 to 12 BTDC. Our engine runs bad at 10 and is hard to get restarted after hot. Am I doing this right. 10 degrees on my digital timing light puts my balancer mark at Zero on chain cover tab? Thanks. Andy.
 
#4 ·
I did the best I could. I got the coarse TDC by seeing where the Rotor was pointing to #1 instead of 180 off. Then using an indicator , I watched the peak rise and fall on the indicator dial. When I was at TDC on the indicator I was also on the ZERO mark on the balancer. I have to (for now) assume I am at TDC #1.
I may have a different problem if you want to read further down. Thanks for your response. I am 327 stupid but I do have some tools and the sun is out and its 50 degrees outside.:)
 
#6 ·
OK, so I found TDC



and I am adjusting valves.
The method I am using is ,,,
At TDC, adjusting E-1, 3, 4, 8 & I-1, 2, 5, 7.
Then one turn to mark and adjusting E-2, 5, 6, 7 & I-3, 4, 6, 8.
I inspected all the rocker arms, balls, and nuts. I also ran all the pushrods around on a nice piece of glass to check for bends. All straight.



BUT there is weird problem on #7 Exhaust!!!!!!!!!!!!

When I check for ZERO backlash on #7 Exhaust, I can push the pushrod down about 0.140 before it stops. It has enough spring pressure to push me back up.





This feels like the spring inside of a lifter allowing me to fully seat the pushrod and then its strong enough to push the pushrod back up.
In other words, I could have zero backlash at one area, but then push the pushrod down 0.140 and obtain a zero backlash at that setting.
I can push my pushrod down, pretty easy, about .140 and it springs back up.
IS THIS NORMAL? I didn't have that happen on any other valve, just exhaust #7.

Another thing, it started to have a distinct PING or KNOCK on one cylinder. That's why I started with the valve adjustment first. Do I need to remove intake and start going thru the engine. It was a great running engine until last week. We started it and it started missing. Thanks yall.:)
 
#7 · (Edited)
When you say it runs "bad" at 10 BTDC, exactly what do you mean? Are you talking about the performance on the road is bad or it's bad because it's hard to start, or ?

Does it run better at a lower or higher idle timing (idle timing is called initial timing)?

Besides the timing at idle you need to know the total timing (total timing is idle timing plus mechanical advance, but not counting vacuum advance), and at what rpm the total timing is all in by. To check the timing, you first have to remove the vacuum hose to the advance canister and plug the line so there's no vacuum leak. Only then can you get a reliable timing reading.

The vacuum advance should cause the idle speed to increase along with the timing seen with the timing light when you hook it up to a full-time vacuum source at the carb. A full-time vacuum is called "manifold" vacuum. Hooking the vacuum advance to manifold vacuum is usually preferred over ported vacuum. Ported vacuum is not there at idle, only there when the throttle blades are opened some.

With the valve adjustment on the lifter that you can push down, you want to set the preload with the lifter all the way at the top of its travel. If there's noise from that lifter after it's adjusted correctly, you may need to go into this deeper.
 
#8 ·
.........

With the valve adjustment on the lifter that you can push down, you want to set the preload with the lifter all the way at the top of its travel.
Thanks for the reply. I need to study everything you said before I answer you back. However, I am working the problem related to the last thing you said.
Do you mean,,,After the valve is adjusted, I should or should not be able to push the rocker down this extra .140 travel? Its pretty easy to push down.
Do I need to remove all clearances (this .140) and then adjust the valve? Thanks.
 
#12 · (Edited by Moderator)
Colbalt327 Thanks again. We decided to go with the pull the manifold and do the lifters job. I am still trying to figure out what engine specs I have. The engine block number is 3782870, its got 350?, heads, and I dont know whats inside. Last week it ran like a 60's rail dragster. We **n luv it and dont want to damage it.



I think I will get a full set of lifters at the Chevrolet dealership. I also saw a little bit of damage on 2 pushrods right at the oil hole so they will get replaced too. But I wonder if I should loose my cast iron intake and go to aluminum? I like the cast iron intake.

Also about the vacuum for the distributor. There are two ports I question. My distributor is hooked up to "A". Should it be hooked up to "B" instead? Thanks.

 
#15 ·
Colbalt327 Thanks again. We decided to go with the pull the manifold and do the lifters job. I am still trying to figure out what engine specs I have. The engine block number is 3782870, its got 350?, heads, and I dont know whats inside. Last week it ran like a 60's rail dragster. We **n luv it and dont want to damage it.

I think I will get a full set of lifters at the Chevrolet dealership. I also saw a little bit of damage on 2 pushrods right at the oil hole so they will get replaced too. But I wonder if I should loose my cast iron intake and go to aluminum? I like the cast iron intake.

Also about the vacuum for the distributor. There are two ports I question. My distributor is hooked up to "A". Should it be hooked up to "B" instead? Thanks.
OK, just saw this. Before ordering up a set of lifters that you may not need, get the one bad one out and take it apart and see what you can see.

I would much prefer you to use just the plunger from a new lifter in your old lifter body (replace the guts, in other words), than to try to get away with using a new lifter (or a set of new lifters) on a used cam. Fixing the original lifter by cleaning is the best case. Next to that, replacing the guts of the old lifter, then next would be to use only ONE lifter to replace the unrepairable lifter. Last choice, and one I just cannot recommend under ANY circumstances, is to replace ALL the lifters with new ones.

The reason is pretty simple, really. If one lifter is replaced, only one lobe and one lifter will be ground up into the motor oil to act as sandpaper to ruin the engine. If the entire set of lifters are replaced, the chances are more than one lifter and cam lobe will fail, and the amount of sandpaper in the engine will be a lot greater.

If it turns out that the bad lifter is trashed on the bottom where it contacts the cam, consider the cam trashed, too. In that case, replace the cam AND lifters as a set. It sounds expensive, I know. But it's less expensive than replacing the lifter(s), then having to tear the engine back down again to clean it of the ground up metal caused if/when the cam and lifter fail, then having to replace the lifters a second time along with a new cam, including another set of gaskets and more oil and filter.

BTW, be sure to use this link to the page on taking the lifter apart.

Intake:
An aluminum intake would be a good addition to your engine. Especially if you're using an adapter to mount a Holley carb on an intake made for a spreadbore Q-jet carb.

If your truck has a mild cam I might go with an Edelbrock Performer EPS (p/n 2701 for satin finish, for '86-back heads).
If the cam is bigger, I'd use a non Air Gap Edelbrock RPM (p/n 7101, satin, for '86-back heads).

BUT before buying an intake, you need to see what heads you have. The bolt holes changed on '86-'95 heads, then again on '96-up heads.

Having 15 inches of vacuum could mean you have a bigger than stock cam, or it might need more initial timing. It might even have a vacuum leak. Does it have a "lope" to the idle, or is it very smooth?

Ignition:
You are hooked up to ported vacuum. It might run better using manifold vacuum (the vacuum port on the baseplate). Try it and see. The problem is sometimes the vacuum advance gives too much advance. Usually 10 to 12 degrees added vacuum advance is about right if you're using manifold vacuum and a good amount of initial timing. It won't hurt to try using manifold vacuum, though. You will find that it will increase the idle speed, so be ready to lower it and to readjust the idle mixture screws to get the highest idle speed, or highest vacuum if you have a gauge.
 
#18 ·
Bummer! I didn't want to think the reason the lifter wasn't holding pressure was due to it being worn all the way through the lifter, into the oil chamber. But that's what has happened.

No repairing that lifter, and the cam is toast, too. I can only give you my best advice: Do not try to salvage the lifters (ANY of them), and do not try to reuse the cam. The result will be 100% failure. No way will another lifter EVER run on that lobe that the bad lifter was on- no way, no how.

This is a tough break, but it happens. After you have cleaned the engine out and inspected the bearings and such, use the following info to help avoid any more problems:

Valve train points to check
Cam break in
Adjusting hydraulic lifters
 
#20 ·
We are not going any further. Its time for a teardown as you guys prescribed. :sweat::(I would like to hear the opinions about the new parts going back in. We wanted to get everything from Chevrolet. Or is Summit Jegs Speedway just as good. I read stories about aftermarket hard parts being kinda soft.
 
#23 ·
Thanks, a lot of guys have added their knowledge to those pages through the years.

For the most part, hard parts from Summit and Jegs, etc. are fine. Even things like camshafts from Summit have shown to be good quality.

That said, there ARE some parts that are coming in from overseas (China, mostly) that you have to be careful of. Some are OK, others not so much.

If you want to, toss out what you are thinking about getting before ordering and get some opinions on them.

In the meantime, if you do a search here and on the internet in general, you can get reviews on the different manufacturers. One databank is Hotrodders company reviews.

When you get into the chinese speed parts, there are varying opinions. Some guys do not like them because they come from a communist nation, others have problems w/the quality. I'll leave the decision to you on how you spend your money.
 
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