So due to standard type 4 oil pumps being in short supply these days, which type 1 oil pump is suitable for a type 4 build? Or is it better to go with an aftermarket type 4 copy?
What’s wrong with the type 4 pump? A CB Performance 1829 maxi pump 1 with 26mm gears should be a suitable replacement but you must check OD (they are often undersize) and the clearance to the cam. https://www.cbperformance.com/product-p/1829.htm
Cheers 77 Westy. The CB performance pump was the aftermarket pump i was considering. Nothing wrong with the type 4 pump just a shame you can’t get a new gen VW one anymore. My other consideration was to just use the pump from the motor that’s in the van at the moment in the one i am building. It has good pressure.
The CB performance pumps have Schadek marks on the pump bodies. Basically they are selling a machined T1 pump. So if you cant get a pump but know a machine shop.. I read the blurb on Aircooled.net's version which they dont sell any more... And I note that on a CB Maxi 3 for a T1 theres no key , so you can knock the driveshaft in and out by 2mm to fit different cams..as I did at Techenders in a field on my engine.. Schadek 30mm Oil Pump, Modified for Type 4 is the best oil pump to use in Type 4 engines! Stock type 4 pumps are ridiculously expensive, we have better results for less money by modifying Type 1 pumps for the Type 4 application! Many new oil pumps are of inferior quality these days, obviously we carry the best available, which are genuine Schadeck! Clearances are tight and they wear well. We recommend this 30mm pump in all T-4 engine applications (the oil system can handle the extra volume). Many people are not aware that VW machines the oil pump bore (in the case) to about 2.7559-2.7570�, and the pump body should measure 2.7570� . This results in a perfect or SLIGHT interference fit, which is why you need a puller to get it out (if you don't need a puller, you have an undersized pump). These pumps provide much more pressure than "stock" unmodified pumps! With these tight tolerances, you MUST be careful you don't overwhelm the stock oil pressure relief system. These can easily generate over 200psi on with thick oil and cold weather! When using this modified Type 1 pump on a Type 4 engine with a Type 4 fan shroud (NOT a DTM, 911, or Cali Conversion), you will need to grind down one corner of the stock T-1 pump cover to clear the 7 o clock fan shroud mount boss on the engine case. On a type 4, you will still have to check the cam bolt head to pump body clearance, we have modified this the maximum amount, but even things like your cam gear or cam bolt head thickness can change this clearance, YOU MUST CHECK IT. And the CB Maxi 1 blurb... CB's Maxi Pumps are the only VW oil pumps that have the main drive shaft locked to the pump gear with a wedge key. They can't slip or lose oil pressure. The driven gear runs on a shouldered shaft that locks it firmly in place. It can't be forced through the pump body and jam against the cam gear as with cheaper oil pumps. CB Oil Pumps are manufactured by an OEM supplier and feature full size 26mm gears. The pumps are assembled with closer tolerances than stock pumps to provide increased oil pressure during low speed operation. They slip right in and increase the life of your engine. Maxi Pump 1 - The Maxi Pump 1 is the perfect oil pump for street, off-road and competition. The die cast blue-printed housing features a "pressure chamber" to help provide a constant flow of oil. The added volume and anti-cavitation features of the Maxi 1 make it the top choice for use with external oil cooler and filter systems. The Maxi 1 slips right in to replace your stock oil pump. This model (1829) fits Porsche 914 & Type 4's, but models are also available to fit all T-1, 2 & 3 VW engines. Make certain to order the correct model to fit your engine case and camshaft combination. Make certain that you are installing the correct oil pump and camshaft combination in your engine - See the Oil Pump & Camshaft Selection Instruction Sheet.
CB Performance pumps are manufactured by Schadek but often have a CB (Claude Buggies) cover. A 30mm pump is too large for a type 4 and will overwhelm the stock oil pressure relief system unless a light oil is used and/or the oil system is modified. A 26mm pump is more than adequate for good oil pressure. The 26mm CB 1829 maxi pump 1 has a keyed drive shaft which can be pressed through the gear a couple of mm and the driven gear boss can easily be modified for cam clearance, if necessary. The outside diameter of many Schadek pumps is undersize and if it easily fits in the crankcase it’s too loose. Some people correct this by machining the pump body and shrinking on a sleeve, or by machining ‘O’ ring grooves in the body. I find it easier to simply use a self-adhesive aluminium shim, once the pump is installed the shim cannot move.
The aluminium shim you mention is it self adhesive foil wrapped around the pump body? Is the foil the full depth of the pump which is clamped by the case? And do you then slice the foil where the oil inlet/outlet is. Sorry just trying to get a picture of how you did it. Worry about internal pressure leakage if the seal is not 100%.
There are two things - on the inlet side it can suck air into the pump and drop pressure and on the outlet side it will lose oil back to the sump. So both inlet and outlet need to be sealed well to work. The trick is to find a shim that is just thick enough so it will not fold up as you force the pump in, slackening off the case bolts above and below the pump to reduce the crush on the pump. Insert the pump then tighten again.
Yes, the pump I have just fitted needed aluminium tape the full depth and completely around the pump body with the holes cut out for the suction and discharge. As mike says both inlet and outlet need to be sealed but if the pump is only slightly undersized it may only be necessary to use a piece of tape around each port, or possibly only one.
