vman76nj

I've low vacuum and all the symptoms of a vaccum leak. I plugged every line, did the carb cleaner spray test and used new gaskets on the carb and still has low vacuum so I think it's an internal leak. I'm going to pull the manifold and try some new gaskets.

The car was factory 2v car that someone swapped over to 4v heads at some point. It has Torker manifold with 650 Holley DP.

2 questions:

1) Does anyone have any recommendation's on the gaskets? I'm looking at:

Fel-Pro Performance Intake Manifold Gasket Sets Q1228 - SummitRacing.com
Mr. Gasket Standard Intake Gasket Sets 214 - SummitRacing.com

2) Do I have to drain any coolant before I pull the intake? The radiator hose leads directly to the block on the Cleveland so I'm assuming no.

I'm a total newb so any other tips on resealing/replacing an intake would be helpful. Thanks.

More info: The car/truck is a 1974 Ranchero with a rebuilt engine.

clevelandstyle

I'd go with the Felpro set.

You do NOT have to drain any coolant. It is a dry intake.

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Grabber Green \'70 Mach I 351C 4V 12.32 at 111mph 1.63 60ft. time
Robin Egg Blue \'79 Fairmont 408C 4V 10.50 at 127mph 1.38 60ft. time

redtail

what is your vac reading? does the car have an aftermarket camshaft? when you spray your carb cleaner, what does the idle do? and where did you spray it?

vman76nj

It's about between 7 and 8. It has an aftermarket cam but I have no info on it. The previous owner didn't know anything about the rebuild because it was his son's who passed away. It does look like a high performance rebuild although he said the cam was mild. My mechanic said it didn't sound so mild.

A recent compression test showed the engine is healthy: 180-185 PSI for each cylinder but the car doesn't run so good. Pings, rough idle, and it's slower than it should be IMO. I've got new plugs and wires.

The carb cleaner doesn't have any affect on the idle unless a little gets in the top of the carb. I've sprayed the manifold, base of the carb, and hoses. I've actuall capped all the lines from the manifold and carb and still no difference.

Tuning the carb using the air/fuel mixture screws has no effect. Changing the ignition timing hasn't helped either. The highest I was able to get it was about 5 degrees initial. It's got an HEI ignition if that makes a difference. My mechanic suggested I replace that Chinese piece of crap but it seems to be working so I don't think that's the issue.

KULTULZ

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vman76nj

What is the LMAO about it? Is it because you agree with the mechanic or because he is suggesting that I replace a part that we verified is working?

In full context, I dropped the car off at local mechanic when I first bought it so he could tune the carb, check the timing and give me an overall assessment on why the car ran so rough. He did whatever tuning he could but overall it would take to much time and space in his shop to go over everything since the car was obviously nowhere near stock. He said roughly:

"It looks like you have a vacuum leak somewhere, the cam is aftermarket so it might not be degree'd in properly and that could be the issue. It could be so many different things that I may end up having to tear half the engine apart before it's fixed and I don't have the time and space on my lot. But, you do have one those Chinese made piece of crap HEI distributors so I would change that either way."

It doesn't sound like it, but he was real about the whole thing. He only charged me $30 for everything he did and I still bring my other vehicles to him. He's got a busy lot, so I don't blame him for passing up work on a basketcase.

DanH

HEI china junk dist know for problems

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vman76nj

Is there one that you can recommend as a replacement? The Ranchero is mostly a weekend driver that I'd eventually like to take to the track a few times a year so I definitely want one with vacuum advance. Simpler would be better in my case since this is the first classic car I've ever worked on and was purchased so I can learn on it. When done, I'd like to see it between 300-400 HP.

redtail

To eliminate that HEI as an issue, you can have the HEI dist replaced with a stock dist from autozone. a new stock dist runs about $40, plus a cap/rotor etc.

How is the throttle response? does it rev quickly, or does it stutter, backfire, ect.

a problem with the 4v heads is that they are too big for a street car, they are very doggy until you hit about 3k rpm. Is this an automatic or manual trans?

Does the vac fluctuate?
is it steady at idle, or does it just stall
A real issue you may have is your timing (and your timing curve). dist controls the timing curve, so that may indeed be your issue. You should have more than 5 deg before top dead center at a 750 rpm idle.
What rpm do you idle at? Also you need to figure out where your timing curve is. IE you need to know how man degrees before top dead center you are at at what RPM.

vman76nj

It doesn't backfire at all and never stalls once it's warmed up. The throttle response isn't that good though. It kind of hesitates and lags. I pulled the plugs and it looks like they had a little oil on them. I've read an internal vacuum leak could do that by sucking oil into the intake ports.

The vacuum bounces around 1 degree but the car idles very lumpy at about 800 RPM. It never stalls in park or at red lights but it sounds like wants to.

I had the transmission rebuilt , its an FMX.

The timing was actually retarded a few degrees before zero on the timing tape. I've read it should be between 10-15 so I advanced it as much as I can. Even at 5 degrees, I get some starter drag when the engine is hot.

The car doesn't ping when the engine is cold but once it heats up, it'll ping when it's going uphill or if I really step on it. The way the engine is setup, I think it was meant for higher RPM. It does wake up after 3,000 RPM but I don't think it should run as rough as it does in the lower RPM.

Like my mechanic said there could be a lot of things wrong with it and it does show the symptoms of a vacuum leak. I figured I'd start with the cheap and easy option of re-sealing the intake manifold. I also have a brand new Holley 4150 on the shelf so I can possibly rule out the carb as well during the install. Being new to this, I'm trying to troubleshoot it by making only one change at a time.

vman76nj

Just a general ignition question. If there were a small vacuum leak, is it possible that the previous owner retarded timing to make up for it or does that make no sense?

I almost forgot, the mechanic also mentioned something about slack in the timing chain as a possible culprit.

Bikesandfires

Has the correct firing order been verified? How about cranking it up, THEN advancing the dist to about 12-14* and taking a drive. Vac signal is extremely low. Verify cam specs

redtail

I would reconfirm your timing tape is correctly installed. Bring the #1 piston up to top dead center, (you can verify this with a pencil down the spark plug and you, or a friend turning the engine over by hand and finding *approx* where the piston is at its highest point. this will tell you where your top dead center truly is (if he did a sloppy job putting the timing tape on).

Your vac will increase as you advance your timing, and it reduces as you retard it.

I would encourage you to read up on how to confirm your top dead center, and how to adjust your timing curve through the RPM range.

Does the car smoke when you rev up and then suddenly let off the throttle?

vman76nj

The firing order is definitely correct. I adjusted the timing over 6 months ago but I recall that it stalled when I tried advancing it out that far. I'm not sure how to verify the cam specs. I have no idea what cam is in there. Do you mean measuring lift using a dial indicator or pulling the cam and seeing what I actually have?

DanH

redtail , tell about your experience with the Cleveland 4V heads .
Don't have any do you ? you did read on the net. or some other no nothing

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