Pete Ashby Posted October 30, 2012 Share Posted October 30, 2012 (edited) Im sorry for sounding so thick - but can u just clarify what u mean by bottoming out? ArQe the gaskets / rings possibly too thick? Yes I am getting leaking gasses and blackening where the gasket is being blown away Nobody sounds thick when they ask a question, the thick ones don't know when to ask :undecided: What Richard, Howard and I are suggesting is that your port locating rings are too long since you have had your manifold faced off, this is not an issue with the old GO Devil engine as it does not use port locators but your third generation jeep motor apparently does. If you look inside your manifold ports you may see a shoulder inside as I'm not familiar with your particular block you may find a shoulder cast in the exhaust port of the block. the ring sits on the shoulder, having said that I have come across some types of engine where the locator ring is just a push fit and wedges in as the port narrows either way it doesn't matter which The ring length is designed for a factory spec manifold yours is now shorter by how ever much was removed, do you know how much was taken off to clear?. The result of this is the port locator ring length needs to be reduced by the same amount to maintain the original fit parameters usually this isn't an issue as the port locators are not a machine fit however if yours were tight to begin with or your manifold has had a lot of material removed to clear then it can be an issue. Iv'e had a look in my post war manuals and I have to say I can't see the port rings but if yours is fitted with them perhaps they were a modification? and not covered by my information. I suggest you may try the following: 1. Clean the manifold and block faces to remove all traces of the old gasket and any sealant you used make sure you do not scratch the machined faces, use something like a wide blade flat paint scraper to do this. I use a bearing riffler but you don't need to find one of these, just use the paint scrapper without digging it into the surface. Finish off by a very quick light rub in tight circular motions with some 400 grade wet and dry dipped in paraffin then wipe both surfaces with a petrol soaked rag to clean up. If you are going to leave this overnight give the surfaces a rub over with a clean oily rag to prevent corrosion. 2. Put your port locators into the ports 3. Without the gasket install the manifold and just pinch up the nuts do not torque them at this stage 4. Using a set of feelers see if you can get a 2 thou gauge between the block face and the manifold at any point on a new block and manifold this should not be possible, with yours you may find that you can so try the next size up until you can’t get a gauge in. take a note of the size of gauge. 5. Take the manifold off and remove the locator rings and measure them using a calliper (you can digital ones off e- bay for a very few pounds) 6. Take piece of glass or a mirror and tape a piece of wet and dry 250 or something similar to it add a bit of soapy water to your wet and dry and rub the rings down in a circular motion you are aiming to remove the same amount as you measured with your feeler gauge plus I would suggest 30 thou for expansion. Wash the rings in paraffin to remove any grit. 7. Refit the rings and manifold without the gasket and pinch up as before re measure the gap it should have closed up to under 2 thou. If not you may have a block face distortion 8. Assuming every thing is fine disassemble put a very thin smear of Holts exhaust paste on both surfaces of the gasket and reassemble the whole thing just pinching up the nuts. Start in the middle and working out either side equally to the ends. 9. Torque the nuts from the middle out to ends one on each side at a time to equalise the force your torque settings should be in the range 29 to 35 ftlbs All sounds long winded but it will only take an hour to do the whole thing. You don't say where the burn marks are are they on the manifold face, the block face or both faces ? Pete Edited October 30, 2012 by Pete Ashby Quote Link to comment Share on other sites More sharing options...
Big ray Posted October 30, 2012 Share Posted October 30, 2012 Im sorry for sounding so thick - but can u just clarify what u mean by bottoming out? ArQe the gaskets / rings possibly too thick? Yes I am getting leaking gasses and blackening where the gasket is being blown away The inserts may be TOO LONG, preventing the manifold from compressing the gasket correctly AND evenly. Quote Link to comment Share on other sites More sharing options...
pockers Posted October 30, 2012 Author Share Posted October 30, 2012 Thanks for the replies all now is clear - Im now using a new manifold so has had none of the surface removed in theory Only thing is from memory the locating rings appear to be fixed to the gaskets but I will double check when the new set arrive If lucky I will get it done this weekend if not the week after Thanksa again Quote Link to comment Share on other sites More sharing options...
Pete Ashby Posted October 30, 2012 Share Posted October 30, 2012 Thanks for the replies all now is clear - Im now using a new manifold so has had none of the surface removed in theory Only thing is from memory the locating rings appear to be fixed to the gaskets but I will double check when the new set arrive If lucky I will get it done this weekend if not the week after Thanksa again Your welcome, what I should have added is run the engine up to operating temperature slowly then let it idle for 10 min or so, then turn off and quickly re-torque the manifold nuts to same torque setting and in the same pattern as previously used before the manifold cools, you will probably pull all of them up by a quarter turn. Pete Quote Link to comment Share on other sites More sharing options...
pockers Posted October 30, 2012 Author Share Posted October 30, 2012 Ps the black scorches are on the block top of the centre two ports Quote Link to comment Share on other sites More sharing options...
Pete Ashby Posted October 30, 2012 Share Posted October 30, 2012 Ps the black scorches are on the block top of the centre two ports Hmm OK try my suggestion first before we all start getting gloomy about having to reface the block, the simple cheap options are always the ones to try first.......easy to say...... difficult when it's your motor I know. Pete Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted October 30, 2012 Share Posted October 30, 2012 I think we have got on the wrong track here. This engine is not fitted with rings as we know on Austin, Bedford and GMC, it appears there are rings fitted to the gaskets for No's 1 and 4 exhaust ports, but the centre siamese gasket for 2 and 3 does not appear to have rings. I am wondering if the gaskets being used are from different sources and centre one is thinner and thus not pulling up tight. Also I would be very surprised if the block was bowed at this point. Quote Link to comment Share on other sites More sharing options...
griff66 Posted October 30, 2012 Share Posted October 30, 2012 if its the block that is bowed a leaking exhaust manifold will be the least of your worries! Quote Link to comment Share on other sites More sharing options...
pockers Posted October 30, 2012 Author Share Posted October 30, 2012 I think we have got on the wrong track here. This engine is not fitted with rings as we know on Austin, Bedford and GMC, it appears there are rings fitted to the gaskets for No's 1 and 4 exhaust ports, but the centre siamese gasket for 2 and 3 does not appear to have rings. I am wondering if the gaskets being used are from different sources and centre one is thinner and thus not pulling up tight. Also I would be very surprised if the block was bowed at this point. Yep sorry am away from jeep at present but yes only 1 and 4 have rings gasket were sourced from probably the biggest jeep spare parts company in uk so i am assuming they correct Back to square 1 ? Quote Link to comment Share on other sites More sharing options...
Pete Ashby Posted October 30, 2012 Share Posted October 30, 2012 I think we have got on the wrong track here. This engine is not fitted with rings as we know on Austin, Bedford and GMC, it appears there are rings fitted to the gaskets for No's 1 and 4 exhaust ports, but the centre siamese gasket for 2 and 3 does not appear to have rings. I am wondering if the gaskets being used are from different sources and centre one is thinner and thus not pulling up tight. Also I would be very surprised if the block was bowed at this point. Ah....... that would explain why I couldn't see any rings in the post war manual I've got. You may have a point there Richard with miss matched gaskets, or it may be that the integral rings are binding either way I would still go through the process of 'dry' fitting and trying with feelers as I said before do the simple stuff first. Pete Quote Link to comment Share on other sites More sharing options...
pockers Posted October 31, 2012 Author Share Posted October 31, 2012 Exhaust assembly paste or exhaust gasket paste? Quote Link to comment Share on other sites More sharing options...
Ed Batchelor Posted October 31, 2012 Share Posted October 31, 2012 Check gaskets with micrometer if you have access to one, take a few measurements on each to get a good average well away from edges which will be distorted from stamping process. Quote Link to comment Share on other sites More sharing options...
Ed Batchelor Posted October 31, 2012 Share Posted October 31, 2012 Try switching to stainless steel nuts and using a standard torque figure for whatever size thread the stud is (wont pull threads out like brass). Assume you are using a lb/ft torque figure at present from whatever manual you have and you aren't mixing up and using a Nm setting on the torque wrench or even using an old uncalibrated wrench, you wouldnt be the first! Quote Link to comment Share on other sites More sharing options...
pockers Posted November 1, 2012 Author Share Posted November 1, 2012 All top tips Wrench is new and have triple checked settings Quote Link to comment Share on other sites More sharing options...
Ed Batchelor Posted November 1, 2012 Share Posted November 1, 2012 If it has been blowing for some time there is a chance the block face will have been damaged locally due to the extreme heat passing through the small gap, it can erode the material leaving a weak point for the gasket to seal. Refacing the block or using a reputable exhaust paste are possible options however the latter may end up being temporary if it hardens and starts to drop out due to expansion/contraction at the weak point. Damage should be detectable with a straight edge/fingernail run accross the surface where it blows. Quote Link to comment Share on other sites More sharing options...
pockers Posted November 3, 2012 Author Share Posted November 3, 2012 - reluctant to use non brass nuts for fear of snapping the studs - only been blowing for about 15 miles worth of driving ( limped it home) but have yet to check the block for trueness - good quality exhaust paste ? Any one be more definitive ? I've got holts exhaust fire gum paste (1000 'c ) this suitable? - new set of gaskets arrived today - not had the micrometer on the rings yet however ! - where they are mounted to the gasket the seem quite proud of it (appx 1/3rd of the thickness this could explain it ? Any thoughts how to resolve ? Found some apparently mos ones in the USA - might try those Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted November 3, 2012 Share Posted November 3, 2012 (edited) - reluctant to use non brass nuts for fear of snapping the studs - only been blowing for about 15 miles worth of driving ( limped it home) but have yet to check the block for trueness - good quality exhaust paste ? Any one be more definitive ? I've got holts exhaust fire gum paste (1000 'c ) this suitable? - new set of gaskets arrived today - not had the micrometer on the rings yet however ! - where they are mounted to the gasket the seem quite proud of it (appx 1/3rd of the thickness this could explain it ? Any thoughts how to resolve ? Found some apparently mos ones in the USA - might try those Hi, Without actually seeing this engine it is not easy to understand why it leaks, but I did notice in the page I scanned from the parts list that the rings are only in the two outer gaskets. As the ports look to be the same configuration as the old Willys MB engine (except no inlet) and they did not need the metal rings, I would try the one piece MB gasket (I reckon it will fit but has redundant holes for inlet ports) and see if it cures the leak. Just realised the rings are only there to locate the gaskets as there is only one stud. Edited November 3, 2012 by Richard Farrant added sentence Quote Link to comment Share on other sites More sharing options...
pockers Posted November 20, 2012 Author Share Posted November 20, 2012 Ok so finally had some time to work on the jeep Have straight edged the block and it does not appear warped and no sign of pitting On closer look at the new gaskets they Are appx 1.5 mm thick measured with a caliper- (borrowing a micrometer tomorrow) however the rim of thelocating rings on the 1 & 4 gasket add about another 0.5 mm onto the gasket thus it would appear the no. 1&4 gaskets are appx 0.5 thicker thans the middle 2&3 gasket Me thinks this is causing the leak on the middle (2&3) gasket - what do you guys think? They do sit deep enough into the block If so any ideas re a solution? try to remove the locating rings altogether? Sanding them down doesnt seem possible without damaging the gasket itself? would holts exhaust paste (1000 degree) be suitable to close the gap? I'm running out of ideas Thanks in anticipation Quote Link to comment Share on other sites More sharing options...
pockers Posted November 21, 2012 Author Share Posted November 21, 2012 Or use 2 gaskets on the middle 2&3 port? (im guessing no?) Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted November 21, 2012 Share Posted November 21, 2012 Pockers, I think I suggested much earlier in the thread, that a MB/GPW manifold gasket may well fit although it with have to redundant inlet port holes, as it is a one piece gasket there should be a good chance it will solve your problem which is appearing to be due to inconsistencies between the inner and outer gasket thicknesses. At least it will prove one way or the other. Quote Link to comment Share on other sites More sharing options...
pockers Posted November 21, 2012 Author Share Posted November 21, 2012 Will be ordering an mb set tomorrow Should i fit with exhaust paste? Copper grease or nothing? Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted November 21, 2012 Share Posted November 21, 2012 Will be ordering an mb set tomorrow Should i fit with exhaust paste? Copper grease or nothing? I do not use anything. Quote Link to comment Share on other sites More sharing options...
pockers Posted December 1, 2012 Author Share Posted December 1, 2012 Finally sorted it! Ok so the two outer gaskets were too thick because of the locator rings this caused the inner gasket to leak So using a small flat blade screw deiver and a pair of needle nose pliers i removed the locator rings completly this resulted in all three gaskets being the same thickness - ithen used a smear of exhaust paste on the gaskets to hold them in place on the block, then bolted the manifold on - torqued up the nuts , ran the engine for ten mins then torqued up bolts again Took it for a test drive today and looks all good Many thanks for all the replies and tips Quote Link to comment Share on other sites More sharing options...
griff66 Posted December 1, 2012 Share Posted December 1, 2012 glad u got it sorted i know those sort of snags can be a right pain! Quote Link to comment Share on other sites More sharing options...
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