63 409 overheating & other issues

[smd321]

I haven't entirely given up on this one yet. I thought the chain didn't help, but I was only basing it on my bad cylinder, which actually lost 20 PSI after doing the chain. The next day, I checked all the the cylinders again (no plugs, open throttle) and most of them were better. Confused, I adjusted the preload on the rocker and suddenly I'm up in the 160PSI range now on the bad cylinder. The engine is running a lot smoother now.

So now I have a couple questions:

1. I have hydraulic lifters. When I push down on the pushrod, most of them do not give but several of them feel "springy". I'm assuming that the "springy" ones are still pumped up with oil, and the hard ones have run out, at least until I start the engine again. When I put the pistons to TDC and then rotate the rods to check for tightness, do I need to push the lifter down to take out any residual lift from being pumped up? Or does this not matter?

2. On my Rochester 7025123, I have what appears to be a metered port hooked up on the front left to my vacuum advance. I know generally I want full manifold vacuum for a street car, but most of the pictures I've seen have the vacuum advance hooked up here. Is that correct? I'm wondering if I should hook it up to manifold vacuum instead.

3. Where is the PCV supposed to connect to?

Thanks!!

 

[Jim Sullivan]

Once full of oil, a hydraulic lifter should not compress or feel spongy, by hand. To adjust a hydraulic lifter, when at tdc, loosen the rocker nut and spin the push rod back and forth while tightening the rocker nut. You will easily tell when the pushrod stops moving freely. Then adjust your preload, usually 1/2 to 3/4 of a turn on the rocker nut. Check the book for proper spec(or the lifter manufacturer's spec, if aftermarket lifters).

 

[Don Jacks]

The vac.advance may or may not be ported.With the engine at normal idle,remove the vac.line from the advance unit.If thee engine slows down,it's manifold vac.If not,check the line for vacuum.It's not beyond the possibility that the vac.advance is shot.If it does turn out to be ported,I would convert it to manifold vac.You said the engine was built in the 80's,did you build it? Was everything used written down somewhere? No telling what's been done or what's in there.The point being that setting every thing to "stock" spec's. may not be the best for today's fuels.

 

[1964SuperStocker]

I would say with compression reading like that a rebuild plan is a good plan. Welcome aboard!!!

In general isnt that kind of compression in the 10:1 range (132psi)? I was thinking 150 is probably due to oil from a leaky valve coating the piston/rings from above? Any ideas on that single piston being so high? I need to do a compression check on my motor now to remind myself where mine is at. By the way. My cheap $120 aluminum radiator and $25 16inch electric fan (both off of Ebay) kept my motor right at 200 degrees while running around in the 94 degree weather yesterday. I tried to over heat it by driving it hard and letting it idle for an hour. I think the powerglide is still my biggest issue, keeping my rpms up all of the time.

 

[smd321]

You raise a good point. 10:1 with atmospheric being 14.7 would make even 140 kind of high. I'm not burning oil, so maybe I should try another compression gauge.

 

[La Hot Rods]

The Motor Manual show 150 psi for a 10:1 340 hp engine.

 

[Don Jacks]

And that's minimum compression.160 is a decent pressure for a stock cam 340 horse engine.Don't overthink this,it'll just cost you more work and money.

 

[1964SuperStocker]

Don't forget to adjust for sea level change. Your 135psi would actually only be 113psi if you lived in Denver Colorado and didn't account for altitude.
I just can't help shake the difference between his highest cylinder reading and the rest. Are they all supposed to be 150psi and every other cylinder is junk? or Did someone try and mix and match pistons?

 

[427John]

He will need to get his valve adjustment sorted first before compression readings will be meaningful,he already found one out of adjustment,if any of the misadjusted valves are exhausts that could also lead to high underhood temps.I have experienced what he is referring to springiness in the lifter but it was on a 100,000 mile engine so they may have been worn to the point of bleeding down.If so verify that the spring is at least supporting the weight of the pushrod and if so you will have to use Jim's method of adjustment with the exception that you will need to carefully check for the point of no lash because if you wait until you get drag it will have collapsed the lifter completely.Once you have just reached zero lash then go the additional 1/2 to 3/4 turn.This condition is extremely common on inline six engines due to the completely vertical pushrod and longer pushrods typical of sixes.Once they get a little wear on them the weight of the pushrod slowly bleeds the oil out of them so that when you first start them up the valves tick a little until oil pressure comes up.At least that's my theory,every brand of OHV six cylinder with hydraulic lifters I've ever seen does the same thing after they get some miles on them,and that's all I can come up with as to why.

 

[rstreet]

The vac.advance may or may not be ported.With the engine at normal idle,remove the vac.line from the advance unit.If thee engine slows down,it's manifold vac.If not,check the line for vacuum.It's not beyond the possibility that the vac.advance is shot.If it does turn out to be ported,I would convert it to manifold vac.You said the engine was built in the 80's,did you build it? Was everything used written down somewhere? No telling what's been done or what's in there.The point being that setting every thing to "stock" spec's. may not be the best for today's fuels.

Don one of biggest issues with my 61 348 car was the vacuum advance. Yes the vacuum advance was "shot" and when I got a replacement it was for set up for a later engined car and was doing very funny things the biggest was the total advance was very high and causing driving and spark knocking I had to restrict the total amount the vacuum pot would deliver by blocking the slot some. The old time Sun machine then told me that the vacuum was close enough. The car runs so good now I ain't touching nothing
Robert

 

[1964SuperStocker]

Don one of biggest issues with my 61 348 car was the vacuum advance. Yes the vacuum advance was "shot" and when I got a replacement it was for set up for a later engined car and was doing very funny things the biggest was the total advance was very high and causing driving and spark knocking I had to restrict the total amount the vacuum pot would deliver by blocking the slot some. The old time Sun machine then told me that the vacuum was close enough. The car runs so good now I ain't touching nothing
Robert

Distributors can get you coming and going with timing. If it works don't touch it. I have yet to bump my distributor since it was set at Tri-State dragway last year. I won't do anything to it until I get the car on a dyno.

 

[Don Jacks]

If you have to change the vac.advance,make certian that you get one that's adjustable.Show Cars has them for the older point type stock dist.Another must have for dialing things is a good,"dial back" timing light.With practice one can do the same thing that the good old dist.machines did.I agree,once you've got your curve and driving right,don't fool with it.

 

[smd321]

Ok, we are making progress now. I really thought I had hydraulic lifters, but now I really don't... or all 16 of them are bad. I gapped them all 18/30 TDC and now my cylinders are all dead nuts on 160 PSI compression. Manifold vacuum is 20", vacuum advance is working great now. Temperature holding at 195F idle on a 90 degree day.

The funny thing is I think the SBC fan shroud really was the problem, but not just because of air flow. Until I cut it down, there was no way to turn the motor over to set the valve lash.

 

[Don Jacks]

You can likely tighten the lash on the exhaust up a little,say .024,to make life easier on the rockers.Great news!!!!!!!!!!!!!!

 

[boxerdog]

Any (easy) way of figuring out what cam is rolling around in there? I'm with Don, I might even go 12/18 or 12/20 at this point if I couldn't track down the info somehow, but I wouldn't stress over it. I'm trying to figure out how some were "springy" in post #21???

In any event, it's good to hear that it is making progress without a major teardown.

 

[smd321]

Yeah, I'm confused by the "springy" lifters too. I have never seen anything like it. It was only on 3 or 4 of them. Last night when I did the settings they were not springy. Maybe the rods were bent a little and pushing against the slots in the heads and not centering in the rocker?? I did notice a couple are tweaked and I will be replacing them.

The carb and all the casting numbers I've checked match the 340HP, so I don't understand why I would have solid lifters. Not really knowing the history on this motor, anything is possible. If I somehow had a set of 16 bad hydraulic lifters, would they be expected to function exactly like solids? It seems like a stretch to me.

The lifters click away as regular as a clock now, they aren't even trying to take up the slack.

I did try 12 on the intake and that dropped my compression down to 145 so I went for 18. I didn't mess around with the exhaust, it might not hurt to drop it down a little. Since I have to replace my valve cover gaskets, I think I will get my hands on a dial indicator and see what the lift is. That would at least tell me if the cam is a stock lift or not.

I do intend to go ahead with a rebuild on the other block I have this winter. I'm going to keep my eyes out for a set of the 11:1 heads. Anyone know of any for sale?

Thanks again for all your help...

 

[Don Jacks]

There were no "11-1" heads.only small port[some better than others] heads and large port[690-583] heads.Your 340 horse would have come with the casting number 817 small port head.What hp level are you shooting for? At what the large port cores are going for,you will come out money ahead by getting an aftermarket set from Bob Walla or Edelbrock,Bob's heads preferred.

 

[smd321]

I was thinking of building the 1963 stock 425HP motor. I currently have the 817 heads installed, which I thought were 10:1. I was thinking the 4960 heads were 11:1? If not, is the difference just port size?

 

[Don Jacks]

The difference is the ports and valves are larger.This will require an intake dedicated to large port heads.By the time you find a set of the 690 heads which in core form are going for about 750-1,000 each then pay for the necessary valves,guides,springs and such as well as the machine shop labor,you'd be better off with aftermarket stuff.Put a modern forged piston and aftermarket rods in it,a modern cam,and stay away from the factory 881 intake.You'll have a sweet running,long lasting engine that'd totally embarress anything that came out in 63,Z-11 not included.

 

[IMBVSUR?]

Any (easy) way of figuring out what cam is rolling around in there? I'm with Don, I might even go 12/18 or 12/20 at this point if I couldn't track down the info somehow, but I wouldn't stress over it. I'm trying to figure out how some were "springy" in post #21???

In any event, it's good to hear that it is making progress without a major teardown.

I was working on an engine that I had no knowledge of one time. I too thought they were hydraulics. While starting the lifter adjustment they felt a little loose or springy. Turned out they were solids, the valve springs were just shot to hell. With the good compression, probably not the case here, just an observation