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Discussion Starter · #1 · (Edited)
Hi All

I have bought 2 Autolinea ALU cases from engines that suffered from loosing oil pressure after running a few minutes. I have looked at the pressure relief bores and seat, they look ok. I have checked the case from the oil pick up tube to the oil pump and from oil pump to the gallery for leaks, no leak. Both engines have less than 100 miles on them. The engines was build in CA by a company and shipped to Denmark. Seller did'nt report any issues. Both engines got on the road and are running fine after the case was replaced.

Have any of you guys seen or experienced anything like this with Autolinea cases?? I would like to use these cases soon if I can track down the problem.

/Rolf, Denmark
 

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make sure all oil holes line up with the bearing holes, and get a good align bore done we had some slop in the center main and lost pressure.
 

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Discussion Starter · #4 ·
Use a steel pump with those. They expand with heat better with aluminum cases or so I was told.
Just edited my first post, it is Autolinea alu cases.

This afternoon a third engine came in with the same problem.
Same case as the others.
 

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Maybe take a look at where the suction side of the oil pump lines up with the case opening from the sump tube. I know on the last new mag cases, the case opening was huge. Certian oil pumps had suction inlets that were close to the edge of the case portion/cavity that housed the cam gear, and would actually suck air past the body of the oil pump. Were they all using the same style pump? Which pump were they using?
 

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Discussion Starter · #7 ·
Lost complete oil pressure or low at idle ?? I have one right now that gets low when hot , im gonna be taking it apart soon to insprect .
Oil pressure drops to near zero also off idle. Pressure seems to drop when the engine gets above 3-3500 rpm and pressure would'nt come back before the engine is cooled down. Problem is worst when hot (not too hot).

I will gather parts to build an engine and see for my self what wrong with engine case.

/Rolf
 

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Plunjer not stuck....you have to messure how deep the bore is,we have a case were the depth was more then a AS Case and the taper was way out,so were losing oil presseure at rpm...
2de oil press lost just @idle...wen hot..cheap empi booster spring in de pressure plunjer...never had a problem...
 

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also check the piston size, and bore size. remember bug pack had a batch of small pistons. you can also pressure check the case to see if there is an internal leek. the center cam bearing tower has the transfer groove in it.and the stroker clearancing comes extreamly close to the groove.(even on the mag cases) that grove should of been moved about 1/8" so it wasent neer that clearance knotch. and some people widen the knotch with a round diegrinder burr making it even closer.only widen the groove to the rear where it dosent get closer to the rod clearance knotch. also checl the oil pump fit, you may need a oringed oil pump...but... the first alu case I got had the oil pump feed hole/gally so close I doubt you could oring it saftly.possiably a 1mm "O"ring would do.or a lip seal of you have mad machining skills. and debur the hole so it dosent slice the "O" ring going past it. or better yet, oring the case. also if it is a welded crank:eek:, check to be sure the oil holes are clear of weld,Ive had some that were almost totaly closed up on motors that lasted less than 1000 before they came to me. lifters&bores is another thing to check,Ive had some lifters that were not round,more like an octagonx2 lots of flats on them...not good. we can only make sugestions as we cant see exzactly what you have and whats going on. also I only use 30mm pumps.booster spring on the pressure only,and oe week spring on the cooler relief grooved piston. if it's full flowed as it should be, make sure the gally from the oil pump is pluged(I use push in plugs,not threaded,also on the oil pump outlet that is nolonger used..unless your using a in/out pump then no plugs,but a lot of work to the pump as there kinda restrictive witch will raise pressure in the pump but lower it after and wear parts faster. also look at the center split bearing to see if oil can be escaping at the split.a slight chamfer/removing the sharp edge on the bearing bore during deburring/cleanup can cause an internal leek,thats one plase a sharp edge is needed unless you have bearings that dont have the external groove. good luck and leave nothing to chance.
 

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Discussion Starter · #11 ·
Any Up-dates ??
I have'nt build a new engine on one of the 2 cases I have. But I have looked and measured some more. Plunger and springs are OK, No leak at the sucktion side of the case (full vacuum even when heated). Oil pump not O-ringed (might be a problem) The cases are not pluged in the pressure channel from the pump. Yes the engines was full flowed and pump was pluged but pressure could escape at the pump bore if pump and bore measurements was'nt correct. I don't have the oil pumps used previously so I can't measure them. I think the missing plug in pressure side of the case is a huge mistake and could be the problem.
Will measure the depth of the plunger holes next.

/Rolf
 

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in post #9 what are the "push in" plugs for oil galley marksbug mentioned in the statement about full flowing and where can I buy them


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