Were talking about a fresh 69 350r 4bbl here...Decent cam...

I have been reading and searching and I seen a few threads stating the factory QJet is a 750cfm carb?

I have been getting some detonation out of my new setup which is RPM Intake, and 600cfm Edelbrock carb. I know detonation can be caused by several factors, one being timing, another being lean mixtures.

The car did not detonate prior to installing the new intake and carb. I have not touched the timing. It only detonates when fully hot at 195 to 200degrees, and at some times the car will sputter when taking off from a dead stop or trying to give it more fuel almost as if the timing is way off.

Is there a good baseline on the timing for a setup like this. It is running HEI and not points, Dist is out of a later model Olds and it does have a new vacuum advance can. Fuel pump is also brand new.

As far as I can tell, the engine temp is as the guage tells, checked with an IF thermo over the weekend. I have a new 160 Thermo in it and it does appear to open at 160, the coolant is flowing in the engine. At idle it gets to around 202 and on highway it runs at 180 to 185. I believe factory operating temp for this car was 195 IIRC.

Could the Carb be causing the issue as it's possibly running lean? Or should I be looking at timing issues? Or possibly heat issues?

Thanks in advance.

 

Also, Can anyone confirm that the fuel pump for the 69 Cutlass 350r with 4bbl pump to carb line the one that hooks to the pump itself is 5/16 standard thread bubble end and not 3/8ths flare tip?

For some reason when I replaced the fuel pump that was on the engine after the rebuild, the old pump and line had a 3/8 NPT fitting with a flare and it was 3 lines with the return plugged, where as the supposed correct pump for that year and engine was a 2 line with the 5/16th standard thread bubble type fitting that screws into the pump.

Just making sure that Advance Auto doesn't have something screwy and they sold me a smaller pump which would lead to less fuel perhaps?

The model pump they sold me was part number 40704 which shows a 69 Cutlass with 4bbl.

 

It should, with the195° thermostat that was originally installed. With your 160, it should stay closer to 160°.

Norm

 

^^^^^^^ My first thought, with a 160 stat your are running over 200 at idle? Something isn't right.

You were able to replace the intake with the HEI installed? Double check the timing, maybe you bumped it, but does sound like a cooling issue.

 

Yea, have plenty of room to get intake in and out with HEI installed. Only thing I have ever removed was the Alt, but of course you kinda have to because a bolt goes into the intake.

I put in the 160 Thermo on the advice of the parts guy at the local store. I have also read on here that a lower thermo will let the water circulate to fast through the radiator and actually work the opposite of what its trying to do and make it over heat?? Not sure on that one, just seen it in a few searches on here, but in those same threads people were saying it was a myth. /Shrug

I will check the timing again when I get home, but last I checked, that Dist is in there solid, I went out on lunch to see if I could even move it by hand when trying and it wont budge.

 

The whole "coolant moving too fast" theory has pretty much been debunked. I have found that the RobertShaw/Moroso/Mr Gasket high flow stat did help on an engine, though others have see no improvement. Some replacement units can be restrictive.

 

When I left work, just for curiosity sake, I grabbed a wrench from Maintenance, I moved the Dist counter clockwise (The way it rotates), I only moved it maybe a 1/4" and my Detonation is gone I believe, but I also lost alot of power. I believe the detonation, and the hesitation is def in the timing so I will get that squared away tonight. It should be around 12 degrees BTC when running HEI over points correct?

The cooling problem is a whole other issue which I shall dive into tonight as well. Need to figure out why its doing it then fix it. Not gonna throw money at something until I find the root.

 

What most guys find is that the HEI works best using the timing specs from the HEI equipped cars, which is 20 BTDC at idle with the vacuum advance removed and plugged. Your total timing should be around 36-38 degrees. Have you re-curved the distributor? It can make a huge difference in performance.

What are you running for radiator, shroud, and fan? Most issues involving running warm at idle are air flow related.

 

It has the stock Radiator (Whatever came in the 69 W-31 package), and shroud and the fan is a straight type no clutch. I have not touched the Dist except for replacing the Vac Advance a few weeks back. I am not sure what re curving entails but I will try and search up on it in the meantime.

I can physically see the water flowing, its actually pouring through it pretty fast and strong from what I can see. But, appearances can be deceiving I suppose.

 

http://www.corvettefever.com/techart...wer/index.html

This will get you started, nice read.

 

Well, I started doing process of elimination, I un hooked my Vac Advance, tried sucking on it and nothing changed so I pulled it off. I can barely even press the rod forward so there is no way that vacuum on this can move it. So I believe this may be part of my detonation sine the Dist isn't advancing as it's suppose to.

I went and bought a new one, it moves relatively easy and vacuum on it makes the rod move forward as well. I installed it and it seems to not detonate any more. My main problem is, I need a better way to time this. My timing marker is the stock and from my understanding the notches mean 0, 5 and 10, so how am I suppose to line up to 20 BTDC? My timing light is just an older model that doesnt do anything fancy, if need be I can get one that will get the job done if anyone has a recommendation. I am assuming it's close to 20 but I am not going to guess and leave things to chance, it needs to be timed right.

On to running hot. I removed the cap, let it get up to aorund 180ish and I see a tad of movement but not as it should be. My first thoughts are blockage but I can't think of where. The Radiator was taken to the repair shop when the motor was being freshened up, it was flushed and cleaned and checked and came back ok. The block was tanked, went through etc so I can't think of any bloackage there. Water pump is brand new and so is Thermo. Is it possible the Thermo or Pump went bad already with less than 500 miles on either?

Any other places I can dive into and check for blockages? The only other place would be the heater core, but even still if it had a block in there, it would be the same as bypassing it all together by capping each end off so for the sake of argument, the water would still circulate correct?

I believe with what little flow I have, it's just enough to keep the engine from going past 205ish at any point. Any advice would be good.

 

You can buy a timing tape which goes on the balancer or get a dial back timing light. I would get a high flow stat, they are only $10 and it is a pretty easy install. Chances of WP failure are very slim, IMO.

 

That's actually what's in there. A 160degree high flow Termostat, I think I gave right at 12.99 for it in the performance section at the auto parts store. I believe it was a Mr. Gasket brand? Can't really remember, the parts guy recommended it.... /shrug

I'm second guessing if maybe I was drunk installing the intake and put the Stat on upside down...lol There has got to be something that's blocking the flow for sure, just need to figure out what.

 

Just because you have a 160 stat doesn't mean your going to run 160 deg, maybe in the winter. Your engine temp with an open stat will find it's own temperature based primarily on your radiators ability to cool the anti freeze, the fan size and type, fan shroud, coolant level and capacity, and if it's an aluminum or OEM radiator. I may have missed a few factors related to timing, density of the antifreeze etc. But I feel the main factor on these old cars is the radiator. I think a good aluminum radiator is money well spent. Also a flex fan or electric fans. It's tough to keep an Olds under 190 on the open road on a hot day with the tach running around 3k. I can't do it with a new radiator and a good shroud. Mine will creep up to 200-210 at times even a little more with a 180 stat. I don't think I can do anything else to cool it more. I heard there is a product out there like wet water or something similar that guarantees a 10 degree drop in temp. It may be worth the money but I need to do a little more research.
My 2 cents

 

So o.k. your timing is close and by adjusting the distrib you can get the ping out. Good.

If you'd like to try & keep the advanced timing, try the next higher primary jet or rod from a boneyard qjet. This is a treasure hunt or you can go online and get 'em for $10 bucks or so.

Qjet is fairly deep water though, suggest you get Doug Roe's book on them before wading in.

The key is they're completely vacuum controlled from idle to WOT. Basically the high vacuum = low demand and the carb will give less gas; low vacuum springs and rods rise and give more gas. The game is exactly which springs, rods and jets and there's a huge number of combinations.

Just start close to where you are now and richen one step at a time for a hassle free test. But keep notes so you can go backwards if it gets worse.

Like Hansel & Gretl in the forest...

cf