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Messages - TRLAND

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Maintenance / Re: Vapor lock?
« on: July 02, 2017, 03:23:38 AM »
Hmm... yes i see. Right now the distributor is cast iron with a pertronic ignition module... probably the stock internals other than that.

Its cool out today so no issues with my drive.  I will set it up to 16 degrees in the crank and see how it goes..

Thanks for the direction

I wouldn't do 16 initial unless I knew what my total would be with that and you can't know that until you map your advance curve.  It's important you set it up right to avoid detonation. I was suggesting that 10 is likely still a bit low and you may need to dial in your vacuum advance to get the proper advance at idle which will help with your hot carb issue by keeping the engine cooler. L78 steve was suggesting that may be your issue back in post #7.

Maintenance / Re: Vapor lock?
« on: July 01, 2017, 11:05:43 PM »
Bumped up the timing to 10 degrees on the crank... hope to get out for a drive today. I ran the same set up last summer with no issues of the gas boiling in the carb.

The distributor was bumped over the winter so i hope that is the problem.. although i like the idea of blocking the ports.  Just don't want to take the intake off... again..... haha

What i would like to do is get to 36 degrees total timing but i gave no tach to see if i have ended the mechanical advance

Depends on how much advance is in the distributor now but likely it isn't 26 degrees.  Probably more like 20 so you'd only be at 30 total now.  You should get a timing light with built in tach to find out when you're timing is all in and how much advance your distributor is providing. The timing on my stock L30 with original iron heads running 93 octane pump gas is best at 14 initial, 34 all in at 2800-3000 rpm and vacuum advance restricted to 11 degrees from manifold vacuum. That puts it right on the edge of detonation at WOT but it runs great and stays cool all the time.

Maintenance / Re: Vapor lock?
« on: June 26, 2017, 11:23:50 AM »
Your carb is too hot and it sounds like the fuel is boiling. You don't say what intake you have but make sure you have the right gaskets between the intake and carb.  Here's a post on the subject from the Corvette forums:

Maintenance / Re: hesitation while driving
« on: June 21, 2017, 04:25:02 PM »
The mechanic says he can see the carb leaking and that it needs rebuilt. It was recently rebuilt maybe 4 years ago, and has very few miles on it, but I imagine this can happen when a car sits for an extended time. I'll ask him to show me when I pick it up.

I can't find my receipt or any communication I had with whoever rebuilt it last. Suggestions on a reputable company?

Where is it leaking?  May be just a stuck float but leaking fuel onto a hot manifold is a fire hazard.  Get that fixed ASAP. Lars Grimsrud, Henry Olsen, and Cliff Ruggles are 3 of the best experts on Q-Jets and tuning. Lars rebuilt mine and it operates perfectly.

Research Topics & Reports / Re: First Gen Camaro radiator dates
« on: June 18, 2017, 05:09:19 PM »
1967 RS Coupe w/ AC: 7/2A, LOS, L30, IH OG, A, no tag

Originality / Re: Importance of a Correctly Dated Carburetor
« on: May 29, 2017, 10:06:57 PM »
Lars Grimsrud has a paper titled How to Tune a Q-Jet that covers that. Also, Cliff Ruggles book How to Rebuild and Modify Rochester Quadrajet Carburetors.

This is a 5 year old thread.  You may get more responses by starting a new one.

I agree that timing and tuning are the easy and cheap things to do that can make a huge difference if they aren't right.  Most of it can be done with minimal tools and a clear understanding of what you're doing. If you're new to this as I was a few years back you can get up to speed by reading JohnZ's timing papers on this site (including the one Kurt posted above) or Lars Grimsrud's papers on timing and tuning.  I ended up sending out my carb and distributor for rebuild and setup to Lars because I wanted them done right by an expert. My old 327 performs way better than it ever has.

I also just replaced the timing chain and based on how loose it was, come springtime I'm expecting some improvements from that (not as simple) project. Might be something else you want to check before doing major mods.

I have the valve on a '67 LOS 02A L30 RS with AC and drum/drum

Although its speculative, the last post in the Chevelle forum post above may be the best explanation I've heard for possibly explaining why some people might get decent braking without RPVs, why vendors don't know about them, and why repro manufacturers have abandoned their use in MC ports.

Some feel the RPV is not necessary but if GM included them to begin with, the Chassis Service Manual specifically tells you to use them in a drum brake port, and JohnZ says they should be there, that's enough to convince me that I should have one in my master cylinder.

Agreed on all three points.

Restoration / Re: Where to by correct master cylinder?
« on: November 27, 2016, 04:20:53 AM »
I hate to say it but based on your excellent drawings I'm feeling your pain.  You aren't alone: see Steve68's comments and link in #28 above.  I've been through a similar search to get a correct looking MC with RPVs.  It seems any reproductions have issues when it comes to RPVs.  I considered machining the ports correctly or adding inline aftermarket RPVs but I got lucky with vendors accepting returns and finding a good original rebuilt unit on eBay and I added the RPVs.

Restoration / Re: Where to by correct master cylinder?
« on: November 26, 2016, 11:21:07 PM »

Hard to tell from the pics but are you saying the new brass port that came with the kit will not fit down into the MC because the hole is not machined deep enough? I could be forgetting, but it seems to me the pressed in part on the ones I've worked on are the straight sides at the base of the cone, not the bottom portion of the brass seat. Does the spring fit down into the smaller lip? The rubber flap portion of the RPV should fit into the brass seat.

On my drum/drum MC the spring rests at the back of the port (behind where your smallest hole is). Maybe that MC was designed for front and rear discs so it didn't have provisions for drum brake RPVs.

Restoration / Re: Where to by correct master cylinder?
« on: November 14, 2016, 05:46:13 AM »
There is no two letter code stamped.

I am just wondering now if you order a Camaro specific MC, can you expect the RPV to be there? Or do you have to pull the brass seat to be sure?....Which I would hate to do on a brand new unit.

I mean the ones you order from HBC, Right Stuff, or any of the Camaro parts catalogs.


I would not expect ANY Camaro parts suppliers to sell a new or rebuilt MC with RPVs.  I went through 3 of them sending them back after checking and was told either they weren't necessary or that they had no idea what I was talking about.  I even sent one of the above vendors the picture and link to JohnZ's report from this site to show them what they are and why they're necessary in a drum brake application and they still wouldn't admit I needed them.

You can check if they're there without pulling the brass seat by lightly putting a blunt probe into the port to feel for resistance.

Restoration / Re: Where to by correct master cylinder?
« on: November 10, 2016, 11:28:08 PM »
I could not find the RPVs either when I needed them in a replacement MC a few years back.  I had to buy one of the NAPA MC rebuild kits that John mentions above. So ~$30 for 2 little rubber valves(!) but I also used the brass ports from the kit too even though I didn't damage the old ones when I removed them.

Dave: They are not hard to install. Pull the brass port out by threading a drywall screw into the port and pulling straight out using a claw hammer.  You can get fancy and use a finer thread screw and some washers as a puller so as not to damage the brass port but if you do the ones from the kit can replace those.  Then just put the spring, RPV, and brass fitting back in the port and carefully tap it in place with a socket. Done.

Gary: The spring is only to hold the rubber valve against the back of the brass port. So, no valve, no spring. The springs are included in the NAPA rebuild kits.

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