jw1955buick Posted August 31, 2021 Share Posted August 31, 2021 Been fiddling with this for awhile now, finally did a proper compression check after getting it started, it has never run well so this wasn't totally unexpected, I just didn't think it would be this bad A little history, engine rebuilt 9 years ago in a very cheap manner from what I was told, it came out of a Super so the guy might've just installed new gaskets and an RV cam, whatever that means, then it was driven sparingly for about a year then driven into a barn and parked for seven years with no starting or anything, no fluids drained or checked the entire time, I pulled it out about a year ago and have slowly been cleaning it up, put oil in the cylinders, turned be hand, everything moved easily and the old oil actually looked good, should've done the comp check at this point but I thought it would be alright...guess not so much Link to comment Share on other sites More sharing options...
Bloo Posted August 31, 2021 Share Posted August 31, 2021 How much have YOU driven it? Yeah, that is more spread than you want to see. I'm pretty lenient on that and it's still too much, but... 100psi is really too high for a burned valve, so the engine should tune and run mostly OK. If it has not been driven much since being brought out of hibernation, there may be literally nothing wrong. I wouldn't be thrilled with those numbers, but the compression and leakdown test results on engines that have been sitting a long time are often not very good. It may just need to be driven. Don't write it off yet. 3 2 Link to comment Share on other sites More sharing options...
Ronnie Posted August 31, 2021 Share Posted August 31, 2021 It might not have been driven enough after the rebuild for the rings to be fully seated. Link to comment Share on other sites More sharing options...
jw1955buick Posted August 31, 2021 Author Share Posted August 31, 2021 Drove it around the block until the plugs fouled as I was still messing with timing and the carb, got those two things pretty well figured out, then the brake pedal decided to stay on the floor, new rear cylinders later, I still have a leak someplace to track down before going around the block again Used vacuum gauge for the timing and and have had the engine idling for awhile just to see what it would do,carb sent off for professional rebuild, this is the best the plugs have looked as of yet, it starts but not easy and then won’t start after it’s hot, acts like flooding or vapor lock and this is with an electric fuel pump Pulled and replaced the rocker shafts as they looked pretty groovy, just eyeballed the valve train movement just to make sure it’s all free, there’s no way for me to tell if something is not getting full travel or not, it all looked fine based on my untrained eye it doesn’t idle smooth and I was hoping it was that cam, sounds like a miss and the vacuum gauge was never steady, I haven’t pulled the heads but maybe that’s next? Link to comment Share on other sites More sharing options...
Ronnie Posted August 31, 2021 Share Posted August 31, 2021 19 minutes ago, jw1955buick said: carb sent off for professional rebuild, this is the best the plugs have looked as of yet, it starts but not easy and then won’t start after it’s hot, acts like flooding or vapor lock and this is with an electric fuel pump Could the electric pump be putting out too much pressure causing the float bowl to overfill and flood the engine? That would account for the hard starting and poor running. Plugs look pretty normal for new plugs other than the ones that look like they are running rich. Not bad enough to make the engine run as bad as you are describing. Compression isn't low enough to cause those problems either. I suggest you get the car so you can drive it before doing more to the engine. 1 Link to comment Share on other sites More sharing options...
jw1955buick Posted August 31, 2021 Author Share Posted August 31, 2021 I’ve got a tiny summit gauge in the line showing 5psi, I think 5-7 is the range if I remember but it does act like too much pressure it looks like the original master cylinder so I think that’s next. it’s entirely likely this engine wasn’t broken in properly and then not driven enough miles afterwards, the fella had a battery drain issue and brake problems after the engine was installed and hardly drove it before just parking it indefinitely the miss is slight, not terrible like a dead cylinder or anything, again, It’s been improving the more I do, got it to idle without help around 550-600 rpm then twisted the distributor for max vacuum but that needle won’t stop fluttering I don’t know what else to check internally, if anything, I can put my vacuum gauge on my fuel line and verify the pressure, other than that, get the brakes sorted, top off the leakyflow and try to drive it. 1 Link to comment Share on other sites More sharing options...
Ronnie Posted August 31, 2021 Share Posted August 31, 2021 11 minutes ago, jw1955buick said: then twisted the distributor for max vacuum but that needle won’t stop fluttering Is that the standard way of setting ignition timing for that engine? I would plug all vacuum sources to the engine. If the vacuum still fluctuates there might be an intake valve sticking open or maybe a problem with the cam that was installed. Just a guess... 1 Link to comment Share on other sites More sharing options...
37_Roadmaster_C Posted August 31, 2021 Share Posted August 31, 2021 The nonstock cam MAY be causing an odd idle condition, but for now I would not worry about that. The car was obviously not treated very well in its past ownership. At this point what I would do is add a quart of Marvel Mystery oil and a can or two of Seafoam to the gas and run the engine for an hour or so at varying rpm between 1000 and 3500. This will lube up the rings and valves and help clean out anything that has accumulated due to poor storage. After that run-in check it again. You may find things are a lot better. If not, fix the brakes and do a road run-in. Find some hills close to home and run the car up and down them and around in general. The point is to again vary the engine speed and the load on the engine. This will help to loosen things up, seat things properly and clean things out. After this you will be in a much better place to troubleshoot problems better. As was said above, improper storage does bad and strange things to mechanical equipment! Let us know what you find out. 2 Link to comment Share on other sites More sharing options...
jw1955buick Posted August 31, 2021 Author Share Posted August 31, 2021 I drained the oil first thing and refilled adding one quart of MMO to the regular motor oil, never put any in the gas, I only run pure 91, guess I'll throw some in there too, I tried to do a thorough job of shooting MMO at the valve stems when I had the shafts off, turning it all by hand, no telling if that had any effect, again, the valve train appears to be moving correctly but that's just observation from the top side, studying rocker tip and valve tip wear discussions over in the V8Buick forum, they all appear to be in decent shape. I was really hoping for a better running engine after cleaning all the valve train stuff and new shafts but it made no discernable difference. I'll buy a few products and run it for a longer duration as was suggested and report back. 1 Link to comment Share on other sites More sharing options...
KAD36 Posted September 1, 2021 Share Posted September 1, 2021 Here’s a stream of random consciousness What problem is being chased - a slight miss or rough running? Is it something steady you can hear or feel at idle at the tailpipe, in N and in D, or more random? Unless the vac gauge has some kind of damper adjustment on it the needle or in the line it will oscillate 1-2 divisions like crazy, you have to eyeball the center of the oscillations and that’s pretty normal. Mine has a rotary damper to attenuate the “reverb” reading in the manifold that makes the needle vibrate. These cars don’t have seals on the valve guides unless they are added later. Even with a fresh tight rebuild with valve guides that have seals on the intake added and everything else perfect you’d still see oscillations of an inch Hg or two at idle - my humble experience FWIW. A consistent rhythmic definitive drop at low idle that corresponds to what you might hear at the tailpipe in idle in D w wheels chocked might help you get closer to a root cause. Those plugs look way new, what is the integrity of the wires, points, dwell and cap. Set the timing to 5-7 deg normally. Have tuned up with a vac gauge for timing and mixture purposes before and fell back on a timing light and tach. If you really want to try to time it with the vac gauge its fun to do but can get tricky - the rpms have to be pretty low and after finding the peak vacuum then back off an inch or two of vac - if your gauge is bouncing all around it will be hard to get a good relative reading. The fuel pump pressure sounds reasonable - is it only on electric or both mechanical and electric? How much do you trust the carb settingsWhat’s the carb status? How quiet is the valve train - any stuck lifters? Lastly is your compression gauge one you hold against the port or screw it in. Latter is obviously more consistent, and what temp was the engine when you took it? Noticed one of the wet readings is lower than dry - how much do you trust the data set? Concur with the good feedback you have received it needs to run it more so you personally get the feel of it and can methodically isolate for the miss. FWIW my old worn out engine had 105-110 lbs on compression and it still ran and idled decent. Check off the simpler external subsystems - carb, ignition, fuel - and run it a lot first before you start pulling off heavy duty stuff like heads, rings and valve train/cams. Unless it won’t run then we’re in different territory. 1 1 Link to comment Share on other sites More sharing options...
JohnD1956 Posted September 1, 2021 Share Posted September 1, 2021 Maybe you said so and I missed it BUT, the '55 cam was steel and the later cams were cast iron. As far as I know the steel cam was discontinued ages ago but the cast iron cam can be used in the '55 engine. When you use the cast iron cam you have to change the lifters and the distributor because the '55 lifters and distributor gear are not compatible with the cast iron cam. Also, the cast iron cam would be a '56 cam. And there is documentation that says the '56 cam opens intakes earlier and closes exhaust later with more over lap between the two and because of this a vacuum reading will have fluctuations. So I would not pull heads based on a vacuum reading alone. Link to comment Share on other sites More sharing options...
Oldtech Posted September 1, 2021 Share Posted September 1, 2021 I agree. It needs to be run. like several hundred miles. then a new comp check done. I'd give it a chance. 2 Link to comment Share on other sites More sharing options...
avgwarhawk Posted September 1, 2021 Share Posted September 1, 2021 (edited) I would think that 9 years ago the rebuild kit had matching cam/lifters/rods. At least mine did. Wonder if it was not broken in at first start as it should have been. I would look to pull the intake and valley cover to take a look but only after running the engine for a few hundred miles and there is no positive change in performance. Also, the current running issue my be the reason it was parked? Edited September 1, 2021 by avgwarhawk (see edit history) Link to comment Share on other sites More sharing options...
jw1955buick Posted September 2, 2021 Author Share Posted September 2, 2021 ARRghh! One step forward, five steps back...started it today after adding seafoam and MMO to the gas, after running for a bit when it was warmed up, I decided to spray carb cleaner around the base of the carb, lo and behold big leakage around the throttle shaft and a little around the upper gasket on front side of carb. I sent this off about 8 months ago to a reputable carb shop in California, the thing looked perfect, they mentioned how it was tested on an engine....obviously that couldn't have happened and all for $700🤬 I'm definitely not a tuning guy and this is my first foray into a Buick plus I've never dealt with a WCFB so I've been fighting my own mistakes and inexperience for the last few months, I'm optimistic though, it has gotten slightly better on my watch and I know it'll be back on the road eventually, anyway, I'll answer a few questions asked and start looking for another carb shop that can rebuild the throttle body. I'm totally guilty of just buying things and bolting them on in the hopes that it'll magically run well and be reasonably dependable, it's got a new coil, cap, condensor, rotor, plugs, wires, ballast resistor and points, as far as the engine goes, throttle shafts already mentioned and the stinko carburetor that should've been good. Ran the comp test with the screw in type gauge, I re-tested that one cylinder that came in slightly lower when wet, same results, who the heck knows... Tried my hand at rebuilding the stock fuel pump and failed, it would just eeek a little fuel, not enough keep the carb going though, installed cheapo electric pump and instantly the fuel problems were over, I tried to put the old pump back on and run them both but the old rebuilt pump was somehow restricting the flow, so now just the electric pump, I sent my old dual action to Fusicks this week for a redo, I'd like to run it if I can and have the electric as a backup, that seems to be the best use consensus after reading through the different forums, we'll see. So I don't have the tools or experience to redo the throttle bushings, does anyone know a good carb builder that can be trusted? I think the top half is fine, just that leaky throttle shaft, so should I send in just the throttle body or the whole carb? Link to comment Share on other sites More sharing options...
37_Roadmaster_C Posted September 2, 2021 Share Posted September 2, 2021 (edited) I can not help with a good carb shop. Everyone in the northwest is gone. When you send it in send the complete carb. The shop will actually be more willing to help you if they can see everything they may be asked about and they may find other issues. Keep us posted. Also, the Carter WCFB is an excellent carb and a good shop will make it work very well. If you have specific questions PM CARBKING, Jon is the last word in carburetors! Edited September 2, 2021 by 37_Roadmaster_C (see edit history) Link to comment Share on other sites More sharing options...
EmTee Posted September 2, 2021 Share Posted September 2, 2021 Maybe also try Tom Telesco (telriv) who frequents the Riviera forum. https://forums.aaca.org/forum/73-buick-riviera/ Link to comment Share on other sites More sharing options...
old-tank Posted September 2, 2021 Share Posted September 2, 2021 I researched throttle shaft leaks on mine and it is difficult to impossible. Ended up with different and better throttle body section. I would leave it alone until you sort out the other issues...it is a minor part the problems. 1 Link to comment Share on other sites More sharing options...
carbking Posted September 2, 2021 Share Posted September 2, 2021 First - we are in Missouri, not California, so not our carb. Having said that, there have been billions and billions of pixels on the internet disturbed when they could have been left sleeping, by someone posting about a vacuum leak at the throttle shaft. IF THERE IS NO VACUUM LEAK AT THE THROTTLE SHAFT, THEN THE THROTTLE SHAFT WILL NOT ROTATE! All carburetors will have a vacuum leak at the throttle shaft! The right way to test is with a dial indicator. Tolerances vary, but the design clearance on the WCFB shafts is 0.004~0.006 inch. In use, wear of 0.003 additional is acceptable. This is built into the calibration by the carburetor manufacturer. So if the clearance does NOT exceed 0.009 measured, then look for issues elsewhere. I have yet to see a WCFB that required bushing the throttle body. I have seen a very few that required replacing the primary throttle shaft. If the throttle shaft IS out of spec; then the only issue would be at idle, and pulling away from a stop sign. These issues can normally be addressed by (A) enrichening the idle mixture SLIGHTLY, and (B) adding 50 RPM to the suggested idle speed. We have had tractor carburetors (the governors beat the throttle shafts to death) come into the shop with the SHAFT WORN HALF AWAY. That is correct; a 5/16 inch shaft was now 5/32 where it moved inside the throttle body. Idle was horrible, but tractors ran great in the field. Jon 4 1 Link to comment Share on other sites More sharing options...
jw1955buick Posted September 2, 2021 Author Share Posted September 2, 2021 (edited) Yep carbking, I tried to enlist you to rebuild it at that time but you no longer did that service, you said you just sell the kits. To be sure, it does smooth out with additional rpm’s but don’t all vacuum leaks do that? ill do a caliper check this evening to see what’s what thanks for the specs Jon Edited September 2, 2021 by jw1955buick (see edit history) Link to comment Share on other sites More sharing options...
carbking Posted September 2, 2021 Share Posted September 2, 2021 JW - if I could clone myself half a dozen times, I still could not do all the rebuilds I turn down! Am trying to sell the shop to someone who has the time to run it, and restore carbs, but so far, no interest. Glad to help with the specs. Jon. Link to comment Share on other sites More sharing options...
Bloo Posted September 2, 2021 Share Posted September 2, 2021 (edited) I agree with everything Carbking said about throttle shaft bushings. Speaking in general terms, and not just about the WCFB, a throttle shaft problem, often manifests by the throttle plate getting stuck on the bore and not closing enough for the engine to get down to a slow idle. Sometimes people complain about the little bit of gas that gets out there and leaves a stain on the manifold. That is unavoidable, but a loose shaft will do it a little worse than a good one. A loose shaft (and the attendant worn throttle plates on the secondary of a carburetor that is designed to run with the secondaries sealed (quadrajet, etc.) can cause the secondaries to feed fuel at idle. Almost always, a bad throttle shaft will cause some other big annoying problem long before it gets loose enough for the vacuum leak through the shaft bore to be an issue. Edited September 2, 2021 by Bloo (see edit history) 4 1 Link to comment Share on other sites More sharing options...
jw1955buick Posted September 3, 2021 Author Share Posted September 3, 2021 Pulled the carb off, shafts seem pretty tight and I mean good, not stiff or anything, plates look nice and snug when seated, I guess I have the correct vacuum leakage as others have mentioned, very nice knowing I don't have to deal with that. I found some leakage with the upper gasket btwn the two top halves so a little work to do there. That upper gasket almost seems too thin to really seal well, has anyone had this issue and if so, what was the fix? surely you can only snug down those top carb screws just so much, which I've already done, maybe a tiny bit of sealant or double gasket?? Also anything special to do with the carb to manifold gasket? Or just install it dry and bolt down the carb? I wasn't able to tell if I had leakage there on account of the close proximity of the leaky shaft area on both sides, didn't notice anything when shooting at the direct front and back though so I'm hoping that area is good, the manifold vac port to the old vac fuel pump is plugged so the only other thing is the vac advance line to the distributor. One thing that sticks in my mind is I can't get any reaction from the idle adj screws which I was always told meant a vacuum leak someplace, thoughts? Link to comment Share on other sites More sharing options...
old-tank Posted September 3, 2021 Share Posted September 3, 2021 56 minutes ago, jw1955buick said: One thing that sticks in my mind is I can't get any reaction from the idle adj screws which I was always told meant a vacuum leak someplace, thoughts Idle speed set too high. 2 Link to comment Share on other sites More sharing options...
195354 Posted September 3, 2021 Share Posted September 3, 2021 One thought after reading through this is eliminate any possible vacuum leaks. Block or plug any ports that feed systems like a power brake vacuum tank if it is a power brake car, get to the point of carburetor and engine on the vacuum side. Break out a straight edge and check everything that has a flat surface. Remember that gaskets will seal but you need a flat surface or close to it. One other tool I use is an infrared temp gun then you can see what cylinder is cold or colder that any others. Once you have this information you can start narrowing down your search. I also use a plastic set of pliers then I can pull spark plug wires and listen for a change in the engine. Good luck Steve Link to comment Share on other sites More sharing options...
carbking Posted September 3, 2021 Share Posted September 3, 2021 The idle circuit works because of a negative pressure created by a velocity of air flowing past the edge of the primary throttle plates where the plates meet the throttle body. As the curb idle screw (a.k.a. throttle positioner screw) is turned in, the primary throttle plates rotate open, resulting in a larger opening where the plates meet the throttle body. The larger opening results in lower air velocity. At some point the air velocity is so low what negative pressure created is too low to effect bleedover in the idle circuit. At this point, there will be no discernible difference in idle quality from adjusting the idle mixture screws completely closed; to removing them and placing them in one's pocket. Jon. 1 Link to comment Share on other sites More sharing options...
old-tank Posted September 3, 2021 Share Posted September 3, 2021 Your service manual indicates setting the idle speed at 450 rpm. Adjust the the mixture screws here. Then you can adjust the idle speed to suit your individual requirements. Since my car has factory A/C I set the idle speed at 600 rpm to maintain coolant flow and charging when sitting in traffic. 2 Link to comment Share on other sites More sharing options...
KAD36 Posted September 3, 2021 Share Posted September 3, 2021 Also anything special to do with the carb to manifold gasket? Or just install it dry and bolt down the carb? Have seen a couple different versions of these gaskets. My manifold and carb are early 55 without the heat passage milled in the base of the carb - the gasket that has always sealed best for me has been a relatively thick paper material with a stiff metal mesh bonded in the middle, assembled dry and lightly and evenly torqued down. For whatever reason if I didn’t use that type of gasket I had leaks around the middle between the front and rear bore but maybe it was my lack of experience at the time. If you can’t get it to idle out at 450 to set it up just go up in 50 rpm increments until it does. You really should be able to get decent results at 550. If youve been to carbkings site mind his advice to not set the mixture to get max idle or you’ll get an off idle hesitation like when leaving a stop sign. I fought that for a few years thinking it was the accelerator pump, read his advice, thought it the craziest thing I ever heard then figured what the hell, and leaned it out and presto - right he was! 1 Link to comment Share on other sites More sharing options...
60FlatTop Posted September 3, 2021 Share Posted September 3, 2021 8 hours ago, carbking said: As the curb idle screw (a.k.a. throttle positioner screw) is turned in, the primary throttle plates rotate open, resulting in a larger opening where the plates meet the throttle body. The larger opening results in lower air velocity. At some point the air velocity is so low what negative pressure created is too low to effect bleedover in the idle circuit. You get 'er up there off the idle circuit and the fuel flow through the metering rods gets more precise doesn't it? Sloppy coarse threaded idle screws anyway. Just go from drive to Park after you shut it off. Link to comment Share on other sites More sharing options...
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