Guest 1941 CADDY Posted October 6, 2009 Share Posted October 6, 2009 DOS ANY ONE KNOW WHAT CPANKING COMP. IS ON 6V. 346 FLATHEAD 1941 CADILLAC MOTOR?? HOW MUCH COMP. DOS IT TAKE TO START IT UP?I KNOW IT IS 155 LB. AT 1000 RPM. BUT THERE IT NO WAY THE 6V STARTER WILL TURN THAT FAST.I PUT IN NEW RINGS. NOW I ONLY HAVE 30 LB. ON ALL 8 CYL.IS THAT RIGHT? CAR WONT START.I WOULD LIKE SOME HELP IF SOME ONE KNOWS THANK'L MIKE 1941 CADDY Link to comment Share on other sites More sharing options...
Guest Earl Posted October 6, 2009 Share Posted October 6, 2009 My '41 Buick has right around 95 pounds in each cylinder when it's cold and being turned over by the starter. And that's without opening up the throttle. I don't know what it is when it's hot as when I checked the compression I didn't have the engine running that day. It also has around 50,000 miles on it and is pretty much original. It always starts right up though. Hope that helps some. Link to comment Share on other sites More sharing options...
Guest 1941 CADDY Posted October 6, 2009 Share Posted October 6, 2009 I WONDER IF BECAUSE THE NEW RINGS HAVE NOT SEATED YET. I SHOULD HAVE LEFT THE OLD DOG ALONE.STUMPED THANK'S MIKE Link to comment Share on other sites More sharing options...
Guest Trunk Rack Posted October 6, 2009 Share Posted October 6, 2009 DOS ANY ONE KNOW WHAT CPANKING COMP. IS ON 6V. 346 FLATHEAD 1941 CADILLAC MOTOR?? HOW MUCH COMP. DOS IT TAKE TO START IT UP?I KNOW IT IS 155 LB. AT 1000 RPM. BUT THERE IT NO WAY THE 6V STARTER WILL TURN THAT FAST.I PUT IN NEW RINGS. NOW I ONLY HAVE 30 LB. ON ALL 8 CYL.IS THAT RIGHT? CAR WONT START.I WOULD LIKE SOME HELP IF SOME ONE KNOWS THANK'L MIKE 1941 CADDYYou need to get a hold of the shop manual for your car, and do some research.I think I know where you got the idea of "155 lbs compression @ 1000 rpm". An old "MOTOR" manual ? Not sure how they came up with such an absurd figure. At cranking speed, with all the spark plugs removed, and a good starter & battery, you should see about 110 lbs. compression.Unclear how you could get 30 lbs. cranking compression. Something VERY VERY wrong. VERY wrong. Hard to suggest where to start straightening things out. You might start with an aircraft- type "differential" compression test guage, testing each cylinder at both TDC & BDC. You will be able to hear where you have the MAJOR compression leaks that you indicate you have.What I can tell you is, a properly maintained Cad. "flat-head" of the 1936-1948 variety, will start INSTANTLY hot or cold. It is a magnificent car - well worth your taking the time to "get it right". Link to comment Share on other sites More sharing options...
msmazcol Posted October 7, 2009 Share Posted October 7, 2009 Just as a test put a few drops of motor oil in the cylinders via the spark plug holes. Repeat your compression test. Did you hone, bore or just re-ring? Did you check ring gaps and check for staggered gap placements. Are you sure that the headgasket was dead on and identical to the old one?Just a start. Link to comment Share on other sites More sharing options...
Guest 1941 CADDY Posted October 7, 2009 Share Posted October 7, 2009 TRYED THE OIL TRICK STILL 30LB. NO CHANGE. I AM GOING TO PULL OFF TIMEING COVER AND TAKE A LOOK AT TIMEING MARKS.COULD THAT BE IT?? THANK'S MIKE Link to comment Share on other sites More sharing options...
Guest 1941 CADDY Posted October 7, 2009 Share Posted October 7, 2009 (edited) I ALSO HAD SHOP PUT IN ALL S/S VALVES AND HONE, GRINED HEADS PUT IN THE SPRINGS AND LIFTERS ,CLEAN BLOCK,TEST BLOCK. I DID THE REST.I USED FELPRO GASKITS. Edited October 7, 2009 by 1941 CADDY (see edit history) Link to comment Share on other sites More sharing options...
hchris Posted October 7, 2009 Share Posted October 7, 2009 If the oil in cylinder has not changed anything then I would suggest you have valves open when they shouldnt be, so if all cylinders are down then its logical that valve timing is wrong, or you have set the clearances wrong. Link to comment Share on other sites More sharing options...
Larry Schramm Posted October 7, 2009 Share Posted October 7, 2009 I would not rule out the possible loose head bolt or leaking head gasket? Link to comment Share on other sites More sharing options...
hchris Posted October 7, 2009 Share Posted October 7, 2009 I would not rule out the possible loose head bolt or leaking head gasket?On all 8 cylinders ?? Link to comment Share on other sites More sharing options...
Guest 1941 CADDY Posted October 7, 2009 Share Posted October 7, 2009 WELL YOU GUYS ARE SOME HELP. I'LL WORK ON THE TIMEING FIRST' THANK'S MIKE.MY EYES ARE NOT WHAT THAY SHOULD BE AFTER WELDING 40 +YEARS.THIS TIME I'LL MAKE SURE I WEAR 4 OF THEM.I PUT A LOT OF MOTORS TOGETHER IN THE 60'S. MAYBE I DID IT TO FAST. MY MINE IS STILL 20 YEARS OLD.AND I MISS ALL THE SHOW THIS YEAR. IN THE END SLOW DOWN ,TAKE YOUR TIME Link to comment Share on other sites More sharing options...
Guest 1941 CADDY Posted October 7, 2009 Share Posted October 7, 2009 WELL TIMEING IS RIGHT ON.NEXT I'LL DO A LEAK DOWN TEST.IT BETTER NOT BE IN THE VALVES.IPAID GOOD MONEY AND SHOULD NOT HAVE TO GO OVER A SHOPS WORK. THANK'S MIKE Link to comment Share on other sites More sharing options...
hchris Posted October 8, 2009 Share Posted October 8, 2009 Before you start pulling things apart; can you make an air adaptor out of an old spark plug ?Cut the top insulator off and braze / fix an air hose fitting to the threaded portion of the plug, now install in a spark plug hole, bring piston to top dead centre and connect to some high pressure air ( doesnt have to be too high, even a hand pump will do )If there is a leak, depending where it is, you should hear the air escaping out of the exhaust pipe / carb inlet or bubbles in the coolant.Caution; whilst the cylinder is pressurised the engine could turn over so keep your fingers clear of the fan / pullies etc. Link to comment Share on other sites More sharing options...
Guest 1941 CADDY Posted October 9, 2009 Share Posted October 9, 2009 LEAK DOWN TEST WENT RIGHT PASS RINGS.CALL SHOP TO FIND OUT WHAT WENT WRONG. MY CYL'S ARE NOW 30 THO. OVER.WAS BORD BY MISTAKE. THE GUY SAID HE WOULD BUY NEW PISTONS AND RINGS. HE ALSO SAID HE WOULD PUT THEM IN IF I PULL MOTOR AND DROOP IT OFF.WELL I SHOULD BE RUNING IN THE SPRING. THANK'S TO ALL WHO HELPED ME OUT WHEN I WAS STUMPED,1941 CADDY MIKE Link to comment Share on other sites More sharing options...
Guest Trunk Rack Posted October 9, 2009 Share Posted October 9, 2009 Before you start pulling things apart; can you make an air adaptor out of an old spark plug ?Cut the top insulator off and braze / fix an air hose fitting to the threaded portion of the plug, now install in a spark plug hole, bring piston to top dead centre and connect to some high pressure air ( doesnt have to be too high, even a hand pump will do )If there is a leak, . . . .YOU HAVE RE-INVENTED THE WHEEL. CONGRADULATIONS. YOU APPARENTLY MISSED MY POST NUMBER 4, WHICH EXPLAINED THIS TECHNIQUE.BUT DONT FEEL BAD...APPARENTLY '41 CAD. DIDNT SEE IT EITHER.THE POINT OF THIS POST, IS TO SUGGEST WE DO TOO MUCH REPEATING IN HERE, BECAUSE WE FAIL TO PAY ATTENTION TO EACH OTHER'S POSTS. FOLKS, THERE ARE SOME COMPETENT PEOPLE IN HERE RESPONDING TO YOUR QUESTIONS - MAY I SUGGEST WE ALL READ ALL RESPONSES A BIT MORE CAREFULLY ? Link to comment Share on other sites More sharing options...
Guest 1941 CADDY Posted October 9, 2009 Share Posted October 9, 2009 BEFOR YOUR POST I SAID I WAS GOING TO DO A LEAK DOWN TEST.MAYBE TOU MISS IT Link to comment Share on other sites More sharing options...
Guest Trunk Rack Posted October 10, 2009 Share Posted October 10, 2009 Are you sure you want to have ANYTHING to do with a shop that put an engine together with "standard" sized pistons and rings, and didn't notice how they fit in a "thirty over" bore? Wouldnt you be better off taking them thru a Small Claims Court to get financial satisfaction, and dealing with a COMPETENT machine shop ? We have all made mistakes banging metal together, but that is "over the top" ! Link to comment Share on other sites More sharing options...
Guest 47jag Posted October 10, 2009 Share Posted October 10, 2009 Caddy,My MOTORS manual says it should be 182lbs @1000rpm. I wouldn't have thought a starter could crank 1000rpm so I don't' know how you would measure it.Art Link to comment Share on other sites More sharing options...
Guest Bob Call Posted October 11, 2009 Share Posted October 11, 2009 If this shop bored your cylinders and 1) didn't tell you, and 2) assembled it with standard sized pistons and rings, I would first ask them to pay for a new set of pistons and rings from Egge Machine, and then either 1) ask them to reimburse you for the cost of having the engine torn down and re-assembled, or 2) failing that, ask them to do the tear down and re-assembly while you sit there and watch them during the whole job. Refusal to do any of this, get cost estimates from Egge Machine and a reliable mechanic to do the work and file a suit in small claims court. Link to comment Share on other sites More sharing options...
Guest mena Posted October 11, 2009 Share Posted October 11, 2009 sounds like the guys at the shop readily admitted to an honest mistake and are willing to make in right. court should be a last resort don't you think. Link to comment Share on other sites More sharing options...
Guest Trunk Rack Posted October 12, 2009 Share Posted October 12, 2009 (edited) sounds like the guys at the shop readily admitted to an honest mistake and are willing to make in right. court should be a last resort don't you think.I DISAGREE. THAT IS NO "HONEST MISTAKE". THAT IS A LEVEL OF INCOMPETENCE AND DIS-INTEREST IN EVEN MAINTAINING MINIMUM STANDARDS THAT SHOULD RULE OUT LETTING THEM TOUCH ANYTHING.SMALL CLAIMS COURTS ARE DESIGNED FOR LAYMEN. WHOLE IDEA OF SMALL CLAIMS COURTS IS TO CIRCUMVENT COMPLEX LEGAL PROCEEDINGS AND PROCEDURES, TO MAKE IT EASY TO GET A FAIR RESULT AT MINIMUM COST AND TIME LOSS.PROPERLY EXPLAINED EVEN TO A NON-TECHNICAL JUDGE, I AM CONFIDENT NOBODY WOULD EXPECT YOU TO SUBMIT YOUR MOTOR TO THAT LEVEL OF INCOMPETENCE AGAIN.AS FOR THE COMPRESSION/CRANKING SPEED ISSUE, I SHARE THE CONFUSION OVER THIS "'1,000 rpm" DEAL.OBVIOUSLY, 1,000 rpm IS ALMOST TWICE THE NORMAL IDLE SPEED WHEN RUNNING UNDER POWER! , MAYBE FOUR OR MORE TIMES NORMAL "PLUGS OUT-OPEN THROTTLE" CRANKING SPEED.AS THIS FELLOW FOUND OUT, QUICKEST WAY TO DIAGNOSE ENGINE COMPRESSION ISSUES IS WITH THE STANDARD " DIFFERENTAIL LEAK-DOWN" TEST WE'VE USED IN AVIATION FOR AT LEAST 50 YEARS THAT I KNOW ABOUT ! ANYONE WHO HAS EVER WORKED ON AND/OR OWNED AND DRIVEN A STOCK "346" POWERED CADILLAC (that motor introduced in '36 and continued just about un-changed thru 1948 production, and also used in tanks during WW-2) KNOWS THIS IS A RELIABLE, POWERFUL MOTOR GIVING SPECTACULAR PERFORMANCE FOR ITS ERA, STARTS INSTANTLY HOT OR COLD . (WELL., THAT IS IF PROPERLY SET UP AND MAINTAINED). SAD TO SAY, THIS FELLOW'S TROUBLES INDICATE MY OWN PREJUDICE - THAT THE QUALITY, KNOWLEDGE, OF TODAY'S LINE MECHANICS AND MACHINESTS HAS FALLEN SUBSTANTIALLY SINCE I WAS A KID WRENCH-TURNER AND MACHINSIT'S APPRENTICE. Edited October 12, 2009 by Trunk Rack (see edit history) Link to comment Share on other sites More sharing options...
Guest Bob Call Posted October 12, 2009 Share Posted October 12, 2009 (edited) TRYou are right about the competence of the current generation of mechanics, politicially correct term is automotive technician, and parts store clerks (I don't know the PC term for them). All they know is what the computer tells them. Real mechanics, like my late uncle with a 7th grade education, could listen to a car, truck, tractor, bus, etc., and at most drive it around the block once and know exactly what was wrong and how to fix it. He was not only a expet mechanic, he was a certified welder, certified paramedic, volunteer firefighter and WWII veteran. Edited October 13, 2009 by Bob Call (see edit history) Link to comment Share on other sites More sharing options...
Guest mena Posted October 14, 2009 Share Posted October 14, 2009 The point is that there is no need for a legal proceding, complex or otherwise. The two partys handled it properly to their mutual satisfaction. (so far) Link to comment Share on other sites More sharing options...
Guest 1941 CADDY Posted October 19, 2009 Share Posted October 19, 2009 Up date. I got my motor back from shop.It's back in my caddy. Turn key in started right up.This thing is a dream to drive.The power of the old 346 will run with the best.As I drive it heads turn.All in all it took a long time to get it right. The shop fixed it with no extra cost to me.I AM A HAPPY CALDILLAC MAN. THANK'S TO ALL MIKE Link to comment Share on other sites More sharing options...
Guest DeSoto Frank Posted October 23, 2009 Share Posted October 23, 2009 FWIW, a buddy and I just ran a comparession test on his 1955 Hudson Wasp Custom, with original 202 L-head six, showing 57,000 miles.Cylinders 1,2,& 6 read 110 lbs, 3 & 4 read 105 lbs, # 5 read 115 lbs.Engine at operating temp, cylinders "dry" ( didn't add oil).Most shops manuals of the period use the rule of thumb that all cylinders should test within 10 lbs of one another.Just relating some recent empirical data. Link to comment Share on other sites More sharing options...
Larry Schramm Posted October 24, 2009 Share Posted October 24, 2009 Was the rule of thumb 10 lbs, or 10% from the highest to the lowest? I always heard of the 10% rule. Link to comment Share on other sites More sharing options...
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