I once have read here in this forum something about the vacuum pump or the broken shafts but can not find anymore. so I opened a new thread. I have the problem like many other TR owner that the shaft of the vacuum pump was broken and I wonder why. the shafts are rotating so very easy in the housing that I made myself a lot of thinkings why this shaft alway breaks. those broken shafts I only had until now at the TRs, never at the 512. Now I think I know why those shafts always will break. principal the same pump is mounted in the 512 BB, but there it is rotating clockwise, in the TR anticlockwise. in the 512 the connector for the vacuum hose is vertical to the top, and the oil return hole is down. so all oil can flow back into the cylinder head even when the engine is shut off. on the TR the connection for the vacuum hose is horizontally looking to the left. to the top there is no space to put the hose on because of the distributor. but so the outlet whole for the drainig oil is not down. this is now about 90 ° angle. so in this pump the oil can not drain completly. if the engine is shut off the rest of the pressured oil in the camshaft will flow into the housing. and this housing then is half full with this oil. then starting again the engine this oil will be pressured together because it can not go anywhere and so those shafts will break. I`m just making an adapter with 90 ° angle to turn this complete pump so that the oil putlet hole is like at the BB vertical down. so all oil could go back then. problem is, that the thread is M12 x 1,25 - this is a very unusual thead and I can not find a small 90 ° elbow. so I have to make one. hope tomorrow it is finished? Image Unavailable, Please Login Image Unavailable, Please Login
here is the modified vacuum pump. so you see that the oil outlet whole will be on the bottom and I´m sure this shaft never will brake again now Image Unavailable, Please Login Image Unavailable, Please Login
I have done something similar in my '84 Boxer, just to keep things neat. I have wondered if the pump is actually neccesary? Why is the inlet manifold insufficient to provide barake servo boost as on all other cars? Robert
Romano, looks like you have come up with another solution, will be interested to see if it works, however, I would likely not follow because of the change in appearance--but thats just me. Yes, this topic has been covered in great depth here, and one of the members (Kerry Wittig) even went so far as to design a new shaft that he sells on this site (I have no no affiliation). As for searching, I've found the quickest way to do a decent general search is using the "Search this forum" tab on the RH side just above the listings. That will keep you within the Boxers/TR/M forum, otherwise you'll get tons of hits from all the other F-cars. You can also constrict your search under the general "Search" tab using the advanced options. If you type "vacuum pump" (no parethesis) you will see many posts but down the page is one titled: "Need a Part# 170956-VACUUM PUMP". That has the content described above. Here's a shortcut: http://ferrarichat.com/forum/showthread.php?t=308985&highlight=vacuum+pump Good luck, let us know how the new configuration works out.
I also wondered why or for what this pump will be needed. if there would be also a check valve at the inlet manilfold adapter ( 124342 ) I would say this pump is for faster getting a vacuum for the brake servo. but there is none. very strange to me this pump. so if you would let this pump away you have then to plug the hole in the camshaft. but I´m sure this also would work. that there are cars with electrical vacuum I have not known. but also I ask: for what this eletrical vacuum pump? until know I never measured the vacuum when the trottle is closed. I think that this vacuum then would be good for the brake servo, even if you brake more then once in a short time. because this vacuum pump on the camshaft is rotating only with half revolutions than the crankshaft and can not produce so much vacuum then the pistons when the trottle is closed.
There is a check valve (item 5) in series with that fitting (so it is effectively part of that fitting). The pump's purpose is to generate more vacuum in the brake booster than you get by normally starting, idling, and pulling away gently. I made these measurements at ~5500 ft elevation (and when my pump shaft broke, the first brake application after starting was very weak -- made for some hairy parking lot/driveway maneuvers): Image Unavailable, Please Login
oh steve, you are right ! ! ! I only had a look at the intake manifold. in my car this check valve in not in. so I know now why I mostly had trouble to brake when I was going with very low speed. from hi-speed I always had the feeling as if the vacuum is ok. so thanks for this info. but this is also what I mentioned what this pump is for: to get faster the vacuum
That does seem strange that they would leave the vacuum pump in place, but remove the check valve -- and on your (modified) TR, where the intake manifold pressure could be a positive pressure, it's even more important to have the check valve (but it should be easy to put one in place).
had another look at mine yesterday; mine has a 90 deg. 3/8" connector comming from the inlet plenum followed by an inline check valve, and a straight 1/2" connector with a built in check valve comming out of the vacuum pump. Both are joined at a 'T' piece just in front of the bulkhead. One issue has always been the 'T' piece has 1/2" outlets for the vacuum pump, but the 90 deg. connecter needs 3/8", and vice versa for the inlet. I swapped them over: the 90 deg connection has the same thread as the in line, so I screwed that into the vacuum pump, and crewed the in line connection into the inlet plenum.....so much neater! An added benefit is the 'T' connector has 1/2" pipe for the vaccum pump, which is now correct, and 3/8" pipe for te inlet, which is also now correct. I wonder if it should have been like this orriginally? The inlet in line now has the built in check valve, and the vaccum pump I put the check valve in line along the cam cover supports for the pipe. Robert
every diesel needs a vacuum pump when there is a vacuum brake power assistance. the diesel has no trottle and so no vacuum. I will get such a check valve and put in of course ! if all would be as easy as to put this valve in everybody would do the mechanic job
Here is a long discussion and a resolution to the shaft problem........ http://ferrarichat.com/forum/showthread.php?t=308985&highlight=vacuum+shaft&page=6 Guiding Me Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Very cool Turbo!! Between that mod and an upgraded chromemoly shaft.....low speed braking will improve (back to spec), no metal shavings contaminating the oil and oil shall flow properly to the cam..... Diggin' the rotation Me
512TR/M has both intakes plumbed with check valves going to a Tee rather than having the pump. See the two hoses coming together at the front of the engine? Why not do that mod to a testarossa? Cheaper and wont break. Image Unavailable, Please Login
The (significantly) higher CR of the 512TR/M will give more vacuum at idle so that probably gave them enough margin to eliminate the vacuum pump. Once you get it running (or if anyone else has made this measurement), I'd be very interested in knowing the intake manifold vacum at idle (and the elevation where the measurement was made) on a 512TR/M to compare to the TR measurements that I have. Couldn't find any "typical" value given for this in the 512TR WSM.
Ill take a measurement. The ratio is 10:1 on the TR and 10.4:1 on this M engine. The testarossa being 9.2:1 is enough to make that much of a difference? Without checking P/N's I wonder if the brake booster has been revised on the TR?
US testarossa are 8.8:1. The cross-section drawings & specs in the WSMs seem to show them as being identical -- but the PNs in the SPC are different because the fitting for the connection of the hose to the booster was changed on later 512TR. I wonder if they might have also "improved" the check valve(s). IIRC, the one on my testarossa had a fairly large pressure drop across it -- so please measure upstream and downstream of the check valves -- TIA.
Question about the booster check valve. Is the check valve attached directly to the vacuum pump? There is no check valve in line 6 inches from pump as described by others. I have a heavy pedal and the front brakes lock up if I stop quick. I thought I would check the pump and the check valve but can't find the valve. Appreciate some help here. I traced the hose from the vacuum pump to the "t" and up to intake (looks like a valve there) and to the firewall but no valve unless it is part of the pump assembly.
I might be confused, is the check valve going to the intake manifold the booster check valve that I need to check? That is in place but the drawing confused me until I studies Steve's drawing.