Triumph Repair: Crankcase Pressure 80 Spitfire, crankcase pressure, rimmer brothers

Question
Jim,

This engine has 51K mi.  I put new rings on old pistons.  I had the block and pistons gauged and magnafluxed before putting in new rings and bearings.  Also, had a valve job on heads.  The Weber air filter came with a plastic connector to hook a hose to the bottom of the filter, would that be OK to run the hose to from a sealed cannister in stead onf the intake maniforld?  Any suggestions on where to buy a cannister?  Does anyone sell a complete setup for this, since the cannister and emission stuff has been removed by previous owner.

Also, another quick question...A previous owner removed the J Type overdrive.  I can't imagine why...anyway what would the best way to add back.  I know it requires alot of changing like the drive shaft length an so forth.  I have seen where a overdrive can be bought rebuilt at Rimmer Brothers and Victoria British and I'm guessing it will cost about $1000 to $1500.  I haven't seen many for sell used.  At 65 MPH it runs around 3500 RPM, that's just too much.  Any suggestions on this or just leave alone?

Thanks again,

Dan
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-----Question-----
Jim,

I just put new rings and bearings in in the last couple of weeks, I can't believe that could be the problem, could it?  We did talk about drilling and taping a hole in the Canon intake manifold to help pull the pressure out the tail pipe.  Sounds like that is what you are suggesting.  Should it go form the valve cover to a T with one end to the open air and the other to the intake?  As for the issue of oil leaking out of the front oil seal, is it possible the pressure can be large enough to come out of both dip stick and front seal?   

Thanks again for the help,

Dan
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-----Question-----
Jim,

I have just put a Weber downdraft on my Spitfire after rebuilding the engine and it runs really nice, but I am getting alot of oil coming out of the dip stick.  Is there an easy way to put a PCT system on to ease the problem.  It has the hose from the valve cover going to a tee and then part of the tee goes into the air and the other out of a hose toward the ground.  I am getting some leaking from around the timing chain cover also but I think that is a gasket issue.  My mechanic says that with all the pressure in the engine that it could be pushing oil out the front seal too. Do you have any suggestions.

Thanks,

Dan
-----Answer-----
Dan,

The factory setup for the Spitfire had the vent from the valve cover going into a T fitting.  One leg of the T was connected to the carb and the other leg went to the charcoal cannister located up near the radiator.

What you'd need is a fitting on the intake manifold that you could plumb the valve cover vent to in order to pull some vacuum on the engine.  

Otherwise it sounds like the rings are getting very tired, I had oil out the dipstick hole on my '73.  That engine had cracked most of it's rings.  Luckily I pulled it off the road and had it rebuilt before there was extensive cylinder damage.


Cheers,

Jim
-----Answer-----
Dan,

The best setup is to run the vent from the valve cover into a sealed catch bottle then into the carb, with either a PCV valve or flame suppressor on the carb hose.

When the rings were installed, was it a full rebuild or just putting new rings on old pistons?  If all new, they might not have seated properly.  If just new rings on old cylinders... well... it might not have been the correct answer.

As to the front seal leaking, it's possible that if the seal was marginal to start with then the added pressure could be enough to start a leak there.

I guess before going much further I need the full information on what you have and what was done.  


Cheers,

Jim

Answer
Dan,

What you want to do is apply engine vacuum to the crankcase to help keep oil IN the engine.  At the air filter side of the carb there's some vacuum but not as much as the manifold side.  Worst case is try it and if it doesn't do the job then tap the manifold for a fitting.

The reason I suggest a catch bottle is that it'll stop you from sucking oil straight from the engine into the carb.  Otherwise you can pretty much plumb from the valve cover to the air filter fitting, using a PCV valve to prevent backfires from reaching the engine.  Fitting a T to dump to open air won't really help the situation.  The carbon cannister isn't necessary but if you can't find a new one used ones are normally available on Triumph related websites like www.VTR.org.  That's the Vintage Triumph Register.  Look under the classifieds link.

As to the transmission... it's possible the overdrive failed on the original transmission and was removed from the car.  Or someone had taken the o/d from your car for another car sometime in it's past.

Replacing the o/d trans with another is the most "authentic" way to go, but there are conversion kits available to fit a Datsun (Nissan) 5 speed into the Spitfire.  There may be others offered also, but I know I've seen offers of the Datsun conversion.

Keep in mind that the overdrive transmission uses a different mainshaft than the standard 4 speed, so in order to convert you'll need to either get another gearbox designed for the overdrive or rebuild your gearbox with a new o/d mainshaft.  

In addition to the driveshaft you'll need the o/d gearshift lever (or adapt your old shift lever), the gearbox wiring harness extension and the rear trans mount plate and proper transmission mount.

As to the rings seating, it'd be a good idea to do a compression check, both dry and wet.  "Dry" is normal, ie pull the plug and crank the engine.  For a "wet" test you put an ounce or so of engine oil down the sparkplug hole and test it then.  If the numbers go up dramatically on the wet test it's a sign the rings aren't sealing properly.


Cheers,

Jim