Hawklord Posted August 2, 2021 Share Posted August 2, 2021 (edited) My new fuel lift pump came with 2 gaskets, is this a packing error or do I need to fit both and if so why. Is it advisable to also apply some gasket cement as I am replacing the pump to try and fix an oil leak. Edited August 2, 2021 by Hawklord Quote Link to comment Share on other sites More sharing options...
Hawklord Posted August 2, 2021 Author Share Posted August 2, 2021 Investigating further it looks like there are 2 gaskets to go either side of a "spacer" which my existing pump doesn't have. Searching the web again there isn't a definitive answer to whether or not a spacer is required. It seems that earlier engines had a 10mm spacer but there are conversion kits available for the 300TDI with a 5mm spacer which are supposed to help with the fitting, help with priming and reduce the chance of the arm from breaking. Can anyone offer any advice on whether I should be fitting a 5mm spacer. Thanks Quote Link to comment Share on other sites More sharing options...
simonpelly Posted August 2, 2021 Share Posted August 2, 2021 Had similar concerns recently too when doing work on our 1997 300 Tdi Our engine block does not have any spacers and as such only one gasket required. Some folk have pointed out that different vintages of block have different thickness of machined mount on the block. Came to the conclusion to fit as per factory, i.e. no spacer and one gasket for our build. Simon... Quote Link to comment Share on other sites More sharing options...
Hawklord Posted August 2, 2021 Author Share Posted August 2, 2021 I have also read about the engine block differences but other reports state that by adding the 5mm spacer it allows the lift pump to operate in the middle of its possible travel, thus causing less strain and the priming lever should the operate regardless of the camshaft position which all seems to make some sense to me. Fourby 4x4 are one company selling the spacer mod. Quote Link to comment Share on other sites More sharing options...
western Posted August 2, 2021 Share Posted August 2, 2021 no spacer needed & only 1 gasket between the new lift pump & mounting face on engine block. Quote Link to comment Share on other sites More sharing options...
Hawklord Posted August 3, 2021 Author Share Posted August 3, 2021 I understand that the spacer was not originally fitted but intrigued why they are being advertised as an improvement, there are even YouTube videos about them. Has anyone on this forum actually fitted one ? Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 3, 2021 Share Posted August 3, 2021 My engines are early, a 200 and a 94/95 300, so would have the thicker mounting and no spacer. I still went through a few pumps on the 300. I thought the spacer requirement was dependent on the brand or spec of pump - this is the first time I’ve heard of the block casting having shallower mountings on later units. Adding a spacer should ensure the pump isn’t over stressed, but could potentially lead to insufficient delivery to the injection pump. If the engine runs well at full throttle with the spacer fitted, I’d imagine it can only be beneficial. Quote Link to comment Share on other sites More sharing options...
rednaxela Posted August 5, 2021 Share Posted August 5, 2021 I put a new lift pump on my 300Tdi yesterday. Delphi, from Turner Engineering. The old one seemed ok, but it gave no access to the gauze and I presumed it may have been a bit clogged. The old gasket was pretty thick, almost acting as a spacer in itself. The new gasket with the Delphi unit was only slightly more than paper thin in comparison. The wear mark on the old pump's arm looked to be in the right place, so I reused the old gasket which wasn't damaged. If it leaks, then I'll just look into it again... Quote Link to comment Share on other sites More sharing options...
Hawklord Posted August 5, 2021 Author Share Posted August 5, 2021 I bought a 5mm spacer but fitted a new Delphi lift pump today without using it, but If this pump breaks prematurely then I will fit the spacer next time to see if it makes any difference. Quote Link to comment Share on other sites More sharing options...
reb78 Posted August 5, 2021 Share Posted August 5, 2021 I converted to am electric lift pump. That meant I didnt need to replace the mechanical ones that kept failing anymore! Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted August 5, 2021 Share Posted August 5, 2021 48 minutes ago, reb78 said: I converted to am electric lift pump. That meant I didnt need to replace the mechanical ones that kept failing anymore! Me neither 😁 Mo Quote Link to comment Share on other sites More sharing options...
Troll Hunter Posted August 6, 2021 Share Posted August 6, 2021 Nor me. But the possibility of a thicker casting and the need, or not, for a 5mm spacer, could well explain the several early failures I experienced with lift pumps, including at least one Delphi. For several years, until my strip-down in 2016, my electric pump performed faultlessly and I will certainly be reinstalling it. I have even blanked off the location hole in the block for the mechanical pump. Mike Quote Link to comment Share on other sites More sharing options...
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