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MG Midget and Sprite Technical 1500 Rebuild Ready to Start BBS discussion at MG-Cars.net
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MG Midget and Sprite Technical - 1500 Rebuild Ready to Start
| Okay, Im ready to start my 78 midget for the first time since the complete engine rebuild, including rebuilt Stromberg carburetor. Ive read through the archives about the running in process and still have questions. The shop that rebuilt the engine block and head tells me that the engine needs to start on the first crank and that I need to make sure there is fuel in the carb and the fuel line is pressurized. Everything I have read has said to turn the engine over until I get oil pressure/fuel pressure and then try to start it. The shop tells me that they are not concerned about the bearings because oil pressure will build up immediately. They say they are concerned about the cam and lifters and thats why it has to fire on the first try and run for 30mins at higher than idling RPMs, I think they mentioned something like 2000 rpms. They dont want their special cam lube to be wiped off by turning over the engine. They also told me to use Shell Rotella T SAE 15W-40 oil to run in the engine. Oil and filter change after the first 30mins, then at 100 miles and then again at 500 miles. From what I read on Shells website, this oil is recommended for diesel engines mostly. What do you guys say about all this? I was planning on using Mobile 1 15w-50 oil with Mossmotors Zinc additive. I was also considering just using a straight 30w Castrol. Also, how long would it take to manual pump the mechanical fuel pump to get fuel up to the carb? I have an inline clear plastic fuel filter and Ive spent about thirty 30mins pumping that thing and still no fuel. I really want to try and fire the car up this week, but wont until I get some feedback from the MG community. |
| DLW |
| DLW, I think the Rotella was recommended for it's zinc additive content, but that is old news. I believe most of it has now been removed from diesel engine oils as well. Your zinc additive is a good idea, but I think Mobile 1 is a synthetic, and I have never heard them recommended for a break in. If you are expecting your clear fuel filter to be full, that will probably never happen. If you mean there is nothing in it, then you may have some sort of problem. I think it is possible that the hand pump lever on the fuel pump won't do anything if the engine is rotated such that the lobe has pushed the pump. It may be that rotating the engine a bit will make hand pumping work. I think I remember cam break in is done by varying the engine speed between 2 and 3k. Charley |
| C R Huff |
| DLW, Keep in mind it's quite possible that your rebuilt carb may not be set quite right yet for smooth running and this alone may keep the engine from firing up the first turnover. It's not likely that the slow rpm's of the engine turning on just the starter motor are going to wipe off the cam lube from the cam. More likely the 2000 rpm break-in will do that. The mechanical fuel pump will move fair amounts of fuel per stroke when operating it manually while removed from the block. If you hand-pumped the fuel pump lever for 30 minutes without getting fuel, you have a problem somewhere. Others will surely disagree, but I think the kid glove stuff vis-a-vis running in a new engine is somewhat overstated, perhaps with the exception of the 2000+ rpm for 1/2 hour for the cam and followers and not taking it over 4000 rpm for a few hundred miles. Apparently the setting of the rings requires some revs higher than the cam needs. Make sure is has oil and is getting oil, and Bob's your uncle. FWIW Right now I have ~300 miles on a new 1500 .020 overbore that was rebuilt 5 YEARS AGO, then sat in someone's garage collecting dust and drying out the cam lube. I did no dis-assembly or re-lubrication prior to starting it, other than to look in the fuel pump mounting hole to verify the cam looked good and gloopy with lube and pre-oiling the rings prior to turning over. I'm running it in on cheap 20/50 (that meets the grade spec of the Castrol 20/50 that will replace it) and it runs stronger and cooler every day. Compression is even and correct, exhaust is clean, oil pressure is nominal, in other words all signs are pointing toward an acceptable power plant that will behave properly for many miles and years to come. Time will tell if I've Bug$%red this engine or not, but my money is on not. Be patient without being paranoid, get the details right the first time and it'll be fine. R |
| Richard 1500 5 speed |
| Could it be possible that I have the hoses wrong on the pump? I thought the fuel inlet hose was the top port of the mechanical pump and the outlet to the carb was on the bottom. Can someone verify this for me? When I look at the section on my old cam that corresponds to the fuel pump lever, it doesn’t really seem to move the lever on the pump very much at all. I feel I had manually moved it with a greater variance in range when I was pumping at it. I’ll try taking off the gas cap and blowing air down the fuel line to the gas tank to make sure the inlet line is not obstructed. Do I need to drop the bowl on the carb and fill it with gas for the initial start or just having the fuel pump deliver gas to the carb during turnover (for oil pressure) is enough? |
| DLW |
| The hand pumping should deliver the fuel to the float bowl on the carb, provided you get it working correctly. I can't tell you which line is which. I didn't even know the 1500 had a mechanical pump. Are you saying that your clear filter has zero gas in it? Charley |
| C R Huff |
| Top port ( @ 8 o'clock ) is inlet as you say. Suction on the fuel line might be more productive than blowing down the gas cap. Verify your pump is working by placing a finger on the suction side while operating the lever. You will feel the suction if the pump is in working order. R  |
| Richard 1500 5 speed |
| That's correct, no gas in the clear filter. I also meant that I was blow air from the from of the gas line through to the tank to make sure the line was clear. I will try suctiton to see if I can get gas to the front also. I have a new fuel pump arriving tomorrow because the one I have now has very little suction. I can at least compare the two. No other sugessions on break in oil? John Twist recommends 20w/50 for break in and everything. |
| DLW |
| Hey Dlw, Talk to Gryf, he is our resident 1500 carb guy, it sounds like the diaphram in the stomberg carb has gone to a better place so you might need one of those and some other tid bits Here is one of the best articals I have found for engine break-in, you will have to "copy paste" it into your web browser for it to work. http://www.minimania.com/web/SCatagory/ENGINE/DisplayType/Calver%27s%20Corner/DisplayID/988/ArticleV.cfm Prop |
| Prop |
| Thanks for the article Prop, it was a good read and lots of good info. The new fuel pump can it and my old one is definately not working correctly, becasue this new one I can feel the suction on it. So, hopefully that will solve my issue with getting gas to the filter. Thanks for photo Richard, my new pump looks just like the one you had. I guess my old is the original. |
| DLW |
| DLW: Be aware: the pump in the photo is new, but I had to pull it off my new motor as it was flooding out the Weber DGV. I had to put a boneyard pump back on to properly regulate fuel pressure. Hopefully I can open it up and alter it for proper pressure. If you're lucky I got the only bad one! R |
| Richard 1500 5 speed |
| "It's not likely that the slow rpm's of the engine turning on just the starter motor are going to wipe off the cam lube from the cam." Oh yes it WILL! Slow cranking of the engine with a new cam and followers is known to be one of THE major causes of premature cam/follower failure! " Apparently the setting of the rings requires some revs higher than the cam needs." Other way round I'm afraid. To bed in a new cam/followers it is essential that the cam and followers are well lubed with a high pressure lube designed for purpose and that the motor fire first time (ie no excessive turning at low RPM) because the initial start up is where the most wear will occur. Once fired up I set 3000 rpm for a minimum of 20 minutes - no load on the engine. After this I drain the oil and replace along with a new filter. I then run in over 500 miles using varying engine speed up to 3000 rpm and varying the engine load (no excessive load, but load none the less since this will bed the piston rings in faster/better). I never oil the piston ring since they bed faster this way. Additionally DO NOT use a synthetic oil since this will prevent the rings ever bedding in. After 500 miles another oil and filter change and re-torque the head. Check valve clearances. Robert's your Ma's brother! Note: On race engines , after the initial bedding of the cam, I bed the rings on the rolling road. |
| Deborah Evans |
| Note. With regards to pre start up oil pressure: On a Triumph 4-pot I remove the distributor drive dog and use a length of steel rod machined at the end to engage with the oil pump drive which is spun ANTI-CLOCKWISE in a cordless drill until I see at least 50psi on the gauge. I also always build the bottom ends with Graphogen paste. (On an A Series I pre-lube by pumping oil into the main gallery through the external tapping by the oil filter.) |
| Deborah Evans |
| I defer to Deborah! " Apparently the setting of the rings requires some revs higher than the cam needs." This came from multiple archive thread advice on this very board. "I read it on the internet, it must be true!" "Oh yes it WILL! Slow cranking of the engine with a new cam and followers is known to be one of THE major causes of premature cam/follower failure!" I'm certainly willing to take it on faith, especially from those with a wealth of real-world experience I can only dream of, but I sure wish someone would explain the mechanism involved that makes it so. I ran my engine such: 15 minutes @ 2200 followed by 5 minutes @ 3500, turn off, cool down, repeat. I did crank it once without spark just to watch the oil pressure climb, maybe 15-20 seconds. If/when this engine fails I will certainly report it here, with my tail between my legs! FWIW I paid $250 for rebuilt engine and cylinder head. Makes up for all those crappy parts I keep getting. R |
| Richard 1500 5 speed |
| Thanks for the info Deborah. I have no problem getting the engine ready so that I only have to crank it once. I really hope I rebuilt the carb correctly and that everything else is sound. How long does it usually take to prime the oil pump this way using a drill and rod? I'm assuming I would need to fill the oil filter with oil before starting the whole process? As for preparing the carb, do I just need to make sure gas is in the float bowl? I'm assuming that by hand pumping the fuel pump, it will go into the float bowl once it enters the carb inlet? Sorry, for all the questions, I just want to try and get it right the first time and save myself possible trouble in the future. Richard, I was a little concerned about how much suction this new fuel pump had also because there is a noticeable difference from this one and the original. I too was thinking it was putting too much fuel in the carb. I guess I will find out! |
| DLW |
| Hello Deb, How ya doing doll, Are we good? I didnt know If I over stepped or you where to busy to respond to some old emails being that your in the middle of your race engine. I hope the latter is the case. Can you please elaborate a little more on pumping up the oil pressure on the A series 1275 before 1st start up....I have to admit I was going to turn the engine over for a few secounds with out plus to build up pressure...But with your WISE advice, Which Im so willing and eager to accept when ever avialable, Im not going down that road for building up oil pressure. Can I use an air compressor, and pour oil thur the tube that attches to the spin on oil filter, or force it thur the oil filter hole, not real sure how to approach this new idea Thanks beautiful. Prop |
| Prop |
Well, this past Saturday, I fired it up and it started right from the start. Pretty great feeling after tearing down a barely working engine and rebuilding it back to the point of working, especially from a person who knew nothing about cars 10 months ago. Prior to starting the engine, I primed the oil pump for about 20 seconds to get 40psi at the gauge. I also hand pumped the fuel pump and filled up the float bowl on the carb. After cranking the car, I ran it for about 22 mins at 2000rpm, changed the oil (VR-1 20w/50 Racing Oil w/Zinc) and filter and re-torqued the head. I didnt do the valves, but will do them after I figure out my heating issue. The coolant got up to a temp of 199 degrees F before I shut down the car. I was constantly checking the top of the block and head with an infrared thermometer. Didnt really know what was too hot for either of them but I was clocking around 160 degrees F, if I recall correctly. So it seems I have a problem with heating. I mostly say this because the coolant temp only climbed; it never went down even after I started it a second time after it cooled down for about an hour. I have a new thermostat on the car but it appears to not be opening. I assume the water pump works, because it was fairly new and its not leaking. I think my next step will be to pull the thermostat housing/thermostat and pour coolant directly into the block and then put the thermostat back on and fire it up. Im thinking the coolant didnt reach the bottom of the thermostat to open it up. Any other suggestions or things to look for? Again, I would like to hold off until getting feedback from you guys. I've also included an "after" picture of the engine. I have to find my before pictures. |
| DLW |
| DLW, Glad to hear it mostly went okay. It certainly looks nice. I don't know anything about the 1500, but the plumbing looks a bit complicated, so I would suspect air in the cooling system. I think filling through the thermostat location is a good idea, and after replacing it, I would also try to fill through the plug on top of the thermostat housing. I would follow that proper filling of the expansion tank. You might also run it a bit with the pressure cap removed to allow air to escape. Check the temperature rating on your thermostat, and consider checking it on the stove with a pan water and thermometer. Charley |
| C R Huff |
| DLW: A small flat-blade screwdriver can be used thru the plug hole to depress the thermostat, allowing coolant to "fill" the block, or at least bring liquid right up behind it. Removing your uppermost heaterbox hose will facilitate the elimination of some of the air in the system. If your radiator cap and external catch tank are operating properly, they will help over time as well to remove air in the system. You can check your thermostat without removing it with your infrared thermometer. Keep it pointed at the thermostat housing during warmup. If/when it opens, the number on your readout, that should have been only climbing slowly, will suddenly jump to 180-190-200 degrees or so. Your hand on the large right-side radiator hose(left in your picture ) can tell you the same thing. Cool to the touch, then Ouch! It appears from your picture that the same hose as mentioned above enters the upper portion of your radiator? This is a non-stock arrangement that may be adding to whatever heat problems you are having. This hose should enter the bottom portion of the radiator. There should be no hose fitting where yours appears to be. 199 degrees is not out of the realm of normal for a catalytic car with retarded timing, especially while sitting in the driveway not moving air thru the radiator. BTW, beautiful under the hood! looks factory correct and brand new! R |
| Richard 1500 5 speed |
| C R Huff & Richard, Prior to reading your post I ran the engine without the cap on for about 5min and shut it off just after I got a geyser of coolant spewing out of the thermostat housing. After cleaning off the engine, I topped up the fluid and started the engine again and watched the temp of the coolant. It still went up to about 200 degrees before I shut off the engine. Because I got a geyser, does this mean the thermostat opened and that the water pump is working? I will go out and try the things you all suggested as well. As for the radiator, it has a tag on it that says “Denver Radiators”; this was on the car when I got it. Does it look like I need a new or proper radiator? Could it be that I have too much fluid in the expansion tank. I have it filled to about ¾. At what temp of the coolant should I really start to be concerned if 200 seems normal in my situation? |
| DLW |
| DLW: Is the temp stabilizing around ~200 degrees? I yes, i would say your "custom" radiator, water pump and thermostat are probably all functioning quite nicely. 5 minutes, then geyser, says to me the water pump moves water and the thermostat opens when warmed. On triple-digit days driving uphill my 1500 routinely approaches (but never quite reaches) the 230 mark, holds pressure, does not blow coolant, returns to 195-200 which is it's happy zone on hot days.It runs 185-190 on cooler days. This is with a 180 degree thermostat, 14 degrees BTDC timing, 4-1 header, no catalytic converter, stock engine. You might let it run longer and see where the temp goes, where it stabilizes. 215-220 is hot, but if the system is circulating water and holding pressure (no leaks) you won't hurt the engine. R |
| Richard 1500 5 speed |
| The whole purpose of a pressurised cooling system is to allow it to run at above the normal boiling point of 212. I forget the calculation (if I ever knew) but the standard 7lb pressure cap will permit it to run a good deal hotter - probably as much as 230 as Richard mentions - and still effectively cool the engine. The cylinder head of a health engine properly warmed up is likely to be above boiling point of water. In your photo - I don't see a problem with the top hose arrangement. In effect, you have 2 hoses feeding hot water from the thermostat to the top of the radiator instead of the normal one - allowing faster circulation of water, that is all. A good way to purge air out of the system when filling is to undo the top connection to the heater - this is the highest point on the system so that is where air would otherwise accumulate. Also helps to squeeze the larger bore cooling pipes a few times to pump any air out. This is easier done if you have the softer silicon hoses - Cue Daniel.... Guy |
| Guy Weller |
| So far I've only seen the temp climb when I’ve had it on. Since I didn't know much about where my temps were supposed to be, I've been shutting it off when it gets to about the 200 degree F mark. The absolute highest I let it go was about 206 on a day when it was about 88 degrees F out. So, I don't know if it will stabilize or not. I haven't been able to really drive it yet since I have a leaking clutch slave cylinder and I'm still waiting for the new slave and hose to come in. I'm beginning to relax more now that I know these coolant numbers are not so unusual. My engine is shock, with a cat, shock exhaust manifold and timing not quite set yet but currently at around 10 BTDC at about 1600 rpms. Wanted to resolve possible heating problem first. But, I guess I will go and try to set this now and re-adjust my valve. 10 degree BTDC at 800 rpm and .010 for the valves? |
| DLW |
| DLW, You said, "Prior to reading your post I ran the engine without the cap on for about 5min and shut it off just after I got a geyser of coolant spewing out of the thermostat housing. After cleaning off the engine, I topped up the fluid and started the engine again and watched the temp of the coolant." I'm a little confused, maybe because if terminology. When you say cap, do you mean the cap on the expansion tank, or the plug in the t-stat housing? I guess you meant the plug on the housing. If so, I was suggesting running it a bit with the cap removed from the expansion tank, not with the plug removed. I think it is likely that when you got the geyser, you lost a bunch of coolant from the block/head. Then, when you tried to top up, the cold charge may have closed the t-stat and made it difficult to fill the block, and thus trapped air in the system. Both the idea to push the t-stat open to fill it, and trying to bleed air from a heater hose sound good to me. Charley |
| C R Huff |
| I did mean the plug on the thermostat housing. I understand removing the top from the expansion and even holding open the thermostat to get coolant in the block but dont understand how to do the heater hose. The more I read your responses, the less I believe I have a heating issue. |
| DLW |
| I too am not at all sure that you really do have a heating issue. But you do need to ensure that the system is properly filled without any air trapped in there. As you fill the system and water rises within the block, air is pushed up to the highest part of the system - that is the heater core and pipes - and gets trapped there. All I am suggesting is that you undo the top hose connection to the heater and pull the pipe off as you fill the system. This will allow the air to escape. Then refit the filler plug on the top of the thermostat housing and I would finally top the system up the last little bit through the heater hose until it flows out - then quickly push the hose onto its connector. This should all be done with the heater tap open. Guy |
| Guy Weller |
| I have same method as Guy... I use a funnel to add coolant via the top heater hose. A |
| Anthony Cutler |
| I tried all the methods you guys mentioned and my temp is still climbing. I haven't been able to road test it yet because I'm still waiting for the clutch line and slave cylinder. I must still have air somewhere. When I tried filling up the top heater hose, it started overflowing the thermostat housing, so I put on the plug and then continued just for it to start coming out of the top port on the heater. It seemed impossible to fill the hose to the top and put it back on the overflowing heater port. I've come this far, so won't let something like this get the best of me. |
| DLW |
| I think I resolved the heating issue. I had a heating issue with my 99 Suzuki Hayabusa motorcycle a few years ago. It was the radiator cap, so I tried another new radiator cap on the midget and the temp stayed below at or below 94 degrees F at idle. I will test drive it today to make sure. But the radiator cap I put on it after the rebuild was purchased brand new. I guess everything you buy from these places need to be tested first. I can't tell you how many defective parts I've received since the start of this project. Thanks for all your comments. |
| DLW |
| Doesn't a sealed (pressurized) system run hotter than one open to atmosphere? R |
| Richard 1500 5 speed |
| I still think your dealing with traped air in the system. leave the cap of and use old towels to cover and catch escaping fluid, you really need to let the engine run with the cap off for about 20 minutes or so at ...idle. No doulbt it will geyser and steam will pour off just keep a 5 gallon bucket of water to pour on the radiator ONLY and ONLY if it gets to hot, and set up an electric fan in front of the radiator so it can get some freash air....it sounds like it really needs to run un-capped for 20 minutes to a 1/2 hour inorder to work all the air out, put the cap back on and run for another 20 minutes and watch what happens, let it cool for an hour, and start it up agian...most likely it will stablisse by this point. Prop |
| Props Black Hole |
| Alright Prop, I'm going to give it try. I guess it's true that a working cap just raises the boiling point so it probably isn't fixed. Hadn't had a chance to test drive, been working on front end. So Prop, you mean for me to take off the radiator cap and not the plug on the thermostat? The first time I got the geyser was by having the plug off and runnng the engine. How would I know if the radiator gets too hot? I have an infared meter - what temp am I looking for? I would imagine the antifreeze will start overflowing out of the expansion tank within the first 8 or 9 mins. If this doesn't work, I guess I should look into flushing the radiator or even recoring it if need be. The radiator appears to be working. The is about a 20 degree difference between the top and bottom once the stat opens up. I guess I refill it up through the top heater hose again? |
| DLW |
| Ive always just pulled the plug in the radiator (large screw). but I dont think it matters much which one, as long as the radiator can vent. As to heat temp oh id say around 205 Id start pouring water "on" the radiator only...not the engine. Just stand by and dont leave the car, and keep an eye on the fluid level, let it do its thing if it starts shooting out steam and gysering fluid keep several towels close by to clean up the mess and keed adding fluid as needed If the temp gets to 210-215 even after cooling down the radiator with a bucket of water and having an electric fan blowing on the radiator the whole time....Shut it down, you definatly got a problem. Something else you might try...Drill an 1/8th inch hole in the thermostat face body, that will relieve the pressure in the cooling system and keeps it from going nukeular when it gets to hot. Unfortantly I dont know much about 1500...but the concept is the same...I do this on my work truck and the one before it and my 1275 midget...just allow the system to vent as it circulates pushing the air out of the cracks and crannies of the engine Prop |
| Props Black Hole |
| Ok, tried this and it improved but after about an hour of driving, I would still start to climb up to about 204 degrees F. So, I just had the radiator flushed and they said it was blocked about 50%. I haven't reinstalled it yet because I want to also install an electric fan. So my question is, if I remove the mechnical fan exactly what do I need to do to slow down the oil pump? I purchased a 10" fan from Victoria British. How do you install this thing? I want to install it as a puller behind the radiator but it looks like I have to attach the fan holders somehow to the radiator cores? Need help :( |
| DLW |
| If your radiator was half-blocked as the shop said, you might want to install it without the fan and see what your temp does. You might not need the fan at all. There are wildly divergent opinions on the fan: I installed one a few years back, couldn't stand the noise of it cycling on and off, so I removed it and used alternative methods to run my 1500 cooler than stock: Header w/ 1 3/4" exhaust Advanced timing NEW RADIATOR Oil cooler Fuel lines heat-wrapped Remote air intake Carb not set too lean You can install the fan in the pusher position and leave the mechanical fan in place. If you are having temp problems why remove a fan? More Fan More Better. The plastic holders run right thru the radiator fins. Oil pump? R |
| Richard 1500 5 speed |
| Great suggestions! I thought that if I removed the fan and clutch it would speed up the the rate at which the oil pump ran? I though I read that somewhere, but maybe not. My mind has been playng tricks on me lately. |
| DLW |
| Why would you want to slow down the oil pump? Most of the time you will slow down the water pump with an under-drive pulley. Doesn't move the water as fast, less hp to drive it. I'd want the oil pump doing everything it can. Also, when I installed an electric on my 1500, I had to mount it as a pusher. It wasn't one from VB, I got it from NAPA but there was not enough clearance between the radiator and the water pump. Might want to check before you get the fan attached to the radiator. |
| Tim Michnay |
| Then I completely remembered this incorrectly, I guess it was the water pump I was reading about before. So, what's an under-drive pulley and is this completely neccessary if I do indeed decide remove the mechnical fan and install the electric fan as a puller or at all for that matter? I will install the newly flushed radiator first to find out if this solved my heating issue. |
| DLW |
| I skipped a bunch of stuff to get down here and post - the mechanical pump is calibrated to deliver the proper pressure. The arm that runs on the cam doesn't actually do the pumping; it just pulls down on the diaphragm to draw fuel in, and then the spring under the diaphragm pushes it back up and pumps fuel to the carb. The pressure is determined by that spring, and the spring is designed to be compatible with the carb's float valve, etc. The arm pulls the diaphragm using a rod shaped like an inverted "T". Once the float chamber is filled to the proper level, the float valve shuts off fuel delivery to the carb. The resultant pressure prevents the pump diaphragm from being pushed up by the spring, so it simply stays down while the arm continues to reciprocate. As fuel is drawn off at the carb and the float valve reopens to admit more fuel, the diaphragm then rises until the arm re-contacts the crosspiece of the "T" and resumes pumping. And for what it's worth, there were two different designs of pumps used on the 1500s. I think it was the later type that added a thick spacer between the pump and the engine block, presumably to keep the pump cooler and reduce fuel vaporization. But the two pump designs used different arms - the one with the spacer had a longer arm so it would reach all the way to the camshaft. So you need to have the right type of pump, but regardless, they should still deliver the same pressure. Cheers, -:G:- |
| Gryf Ketcherside |
This thread was discussed between 03/08/2009 and 17/09/2009
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