BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Oil leak dizzy stump
You may be able to use fluorescent dye to identify your leak.
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DiDueColpi Fred Key West coast - Canada (1365 posts) Registered: 05/14/2010 03:06AM Main British Car: I really thought that I'd be an action figure by now! |
Re: Oil leak dizzy stump
Possibly not from the bolt hole. It's a blind hole and I don't think that there is pressurized oil anywhere near it, other than oil slung up from the timing chain.
If it was a porous or cracked housing I would expect to see coolant more than oil. The traditional leak in that spot is from the valley cover. And I see that your intake manifold doesn't give the clamping coverage that the stock manifold has. I would use those amazing fabrication skills of yours to made a set of longer valley clamps to give that gasket area full coverage. That would probably take care of the mystery leak. Live like you mean it. Fred |
Re: Oil leak dizzy stump
The valley clamps are original but a bit too short because of the manifolds. But they are both really dry.
The bolt hole is NOT a blind hole at least at my engine. As I wrote I changed it to a stud, so no possibilty of leak any more. I'll try another O-ring a bit oversized. But there will be still positive crank pressure anyway. May I mount this: [www.ebay.de] |
Re: Oil leak dizzy stump
I have seen both out of round dizzy shanks and out of round holes in the front cover where the dizzy mounts. These usually cause more ignition problems than leaks, but you can get leaks there if there is excess crankcase pressure. Sometimes breathers alone are not enough, especially during the break in period and the rings are setting. On that note, I have seen many engines built with too large a camshaft or overfilling issues wash down the cylinder liners with excess fuel during break in period, If the cross hatches on the cylinder walls can't hole a film of oil because the gasoline is washing it away with every stroke, the rings glaze and never seat. This leads to excess pressure. Assuming your engine is fine, and you are just getting a little excess pressure, a PCV system hooked up to a vacuum on the air cleaner should do the trick. If that doesn't help enough, then you need to find the source of the excess pressure. Excess pressure usually isn't an issue on the 3.5s, but on the larger engines it can be a real ball buster. I know of several stroker engines running vacuum pumps.
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MGBV8 Carl Floyd Kingsport, TN (4511 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: Oil leak dizzy stump
RPI has long stated that the Rover engines (& Buick/Olds) with 14 head bolts have compression leakage into the lifter valley. Rover eventually eliminated the outer head bolts & quit using the tin head gasket. I may soon remove the heads from my 215 to confirm that this is the cause of my blowby problem.
From RPI: [quote}Every V8 engine we have ever dismantled was suffering from all 8 cylinders leaking compression into the valley (Crankcase) of this engine, thus resulting in 'Crankcase pressurization' that causes many V8 engines to suffer from excessive sludge build up and constant oil leaks around the centre 'Valley' tin gasket, Crankshaft seals, Distributor seal and Rocker covers - this problem can be fully alleviated by the fitting of composite style head gaskets. These gaskets are made of alternate layered material and are slightly thicker than the standard tin gaskets (lower compression by a factor of 0.7-1) and when fitted on the V8 engine will normally alleviate the leakage problem completely, thus curing compression loss, Oil contamination and un-relinquishing Oil leaks. We recommend the use of composite gaskets on most engines. Rover are now using Composite valley cover gasket, and Composite head gaskets also, in addition The Rover V8 engine is being constructed with the 8 outer head bolts omitted, thus further ensuring a gas tight seal.[/quote] More: [www.gomog.com] |
88v8 Ivor Duarte Gloucestershire UK (1041 posts) Registered: 02/11/2010 04:29AM Main British Car: 1974 Land Rover Lightweight V8 |
Re: Oil leak dizzy stump
I recall that later assembly instructions in the Land Rover official engine book for the 3.5, gave lower torque for the outer row of bolts.
Ivor |
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Oil leak dizzy stump
Best left out completely. The 340 doesn't use them.
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Re: Oil leak dizzy stump
Okay gents,
After try&error I think the problem with the dizzy oil leak is solved. Thought that the little but permanent oil puddle under the dizzy stump came from the the bolt hole from the clamp or the O-ring because of too much pressure. Disconnected my additional oil feed pipe for the dizzy, still leaking. Changed the bolt to a stud and renewed the O-ring twice, still leaking. Was sure that the evacuation system (tubes from the breathers to the exhausts to produce vacuum) would be the BIG help to minimize pressure, still leaking. Renewed the dizzy O-ring again, a bit thicker and just fitting in, still leaking. Removed the dizzy again (I don't know how many times) and recognized oil under the cap!! :( After removing the black plastic cover inside the dizzy and after additional inspection I could see a 2 mm high oil puddle at the bottom of the dizzy body! The body has two small holes at the bottom. The Rover dizzy sits at an angle as anybody knows. Not vertical as a Ford or Chevy. One of the hole is at the lower position of the dizzy body when mounted. The addional oil feed for the dizzy is great to minimze the gear wear. But the aditional oil on the gears will cause oil inside the dizzy along the spindle too and that is turning to the top aka the body. When the oil is on a certain level in the casting it will drop through the bottom hole of the casting and hit the timing cover at the area where the clamp sits. I disconnected the feed pipe again and made a 5 miles test drive yesterday. No oil anywhere :) I hope that this problem is solved but that will show a longer run. |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Oil leak dizzy stump
You're saying you had an external oil line to the distributor?
Jim |
MGBV8 Carl Floyd Kingsport, TN (4511 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: Oil leak dizzy stump
Back in the day, on my 215, all 14 bolts were torqued to 75lb/ft. The couple I checked were very close to 75.
Edited 1 time(s). Last edit at 05/15/2017 11:23AM by MGBV8. |
Re: Oil leak dizzy stump
After mounting the second time a brand new dizzy, the problem is solved Smile
The 360 miles trip to SPA proofed that. The other "old" dizzy, that was laying on the shelf for a few years had inside a weak seal that allowed the oil to go up the spindle to the dizzy body and drops out of one of the holes directly on top of the dizzy clamp. Cheers Pitschi |
roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: Oil leak dizzy stump
14 head bolts-or ? Back in the day, I would "add" the four extra, exhaust side on 64'/300 heads. Don't start ! It worked on 3.736 bore motors. Maybe 10 is ok, on cast iron blocks ? Don't know/care. BL Motorsports found out, "split" intake manifolds, allowed the heads to move around much more,(high/extreme performance). Onward, art.
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