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914World.com _ 914World Garage _ New to the board. Big Problem?........

Posted by: Dominic L Sep 3 2005, 07:20 AM

First post here, but I've been lurking here for some time now! Anyway I'm the proud owner of a 1975 914 set up for autocross with a serious oil leak coming from the cylinder, (i think). Could i have a cracked cylinder? The oil (and also looks like exhaust pulses) is coming out between the 3rd and 4th cooling fin on the # 3 cylinder. Pics are attached of the cylinder (circle around the area where the oil is landing) and the underside of the tin. The oily area on the tin is from the same cylinder (#3). I planned on a rebuild (the car sat in a garage for three years) over the winter but i hoped to autocross it once or twice before the winter. Please help. I'm having withdrawl pains from lack of autocross!!

Thanks,
Dominic

Attached image(s)

Posted by: Dominic L Sep 3 2005, 07:20 AM

Pic of tin

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Posted by: ! Sep 3 2005, 07:38 AM

Is it dripping down on the pavement? If not...that's NOT a serious leak.

Posted by: qa1142 Sep 3 2005, 07:39 AM

Check Oil presure sender first. They crack and leak often.

This would leak it that exact area.

Posted by: DNHunt Sep 3 2005, 07:48 AM

Take this for what is worth. Free advice ain't worth much. It looks like the cylinder to head seal is gone. A rebuild looks like a good winter project. I'm kind of conservative so I'd probably not run it, but AX is sure a nice way to stir up the hemarhoids.

Dave

Posted by: Dominic L Sep 3 2005, 07:56 AM

QUOTE (SEEMORE BUTZ @ Sep 3 2005, 05:38 AM)
Is it dripping down on the pavement? If not...that's NOT a serious leak.

Drips about 1 drop every 5 seconds down on the pushrod tube and then the header. Burns before it reaches the pavement!! After the engine cools the residual hits the pavement.

Posted by: Bleyseng Sep 3 2005, 08:00 AM

QUOTE (DNHunt @ Sep 3 2005, 06:48 AM)
Take this for what is worth. Free advice ain't worth much. It looks like the cylinder to head seal is gone. A rebuild looks like a good winter project. I'm kind of conservative so I'd probably not run it, but AX is sure a nice way to stir up the hemarhoids.

Dave

if this is the case Dave then he has a ring problem to blow that much oil out of the head to cylinder seal.

My guess is the oil pressure sender also as its right above that. I just fixed that on the Westy.

Posted by: Dominic L Sep 3 2005, 08:06 AM

QUOTE (DNHunt @ Sep 3 2005, 05:48 AM)
Take this for what is worth. Free advice ain't worth much. It looks like the cylinder to head seal is gone. A rebuild looks like a good winter project. I'm kind of conservative so I'd probably not run it, but AX is sure a nice way to stir up the hemarhoids. :blink:

Dave

Now this makes some sense but will clean oil appear on the fins if it came from the seal area. BTW i retorqued the top head nuts to 23 ft lbs and the leak got worse.

Will, sender is dry as a bone.

Thanks to all.

Posted by: Bleyseng Sep 3 2005, 08:10 AM

Do a compression test to see what that cylinder is compared to the rest.

Posted by: Dominic L Sep 3 2005, 08:10 AM

QUOTE (Bleyseng @ Sep 3 2005, 06:00 AM)

QUOTE (DNHunt @ Sep 3 2005, 06:48 AM)
Take this for what is worth. Free advice ain't worth much. It looks like the cylinder to head seal is gone. A rebuild looks like a good winter project. I'm kind of conservative so I'd probably not run it, but AX is sure a nice way to stir up the hemarhoids. :blink:

Dave

if this is the case Dave then he has a ring problem to blow that much oil out of the head to cylinder seal.

My guess is the oil pressure sender also as its right above that. I just fixed that on the Westy.

My sender is above the # 4 cylinder next to the distributor. It's dry to touch but Ill check it when it's running. Maybe the fan is blowing the oil over the # 3 cylinder.

Thanks

Posted by: DNHunt Sep 3 2005, 08:16 AM

You're right Geoff. That would be a huge amount of oil getting by the rings to drip every 5 sec. By the way I have been there. With that much oil in the cylinders it will barely run and under compression it will foul plugs. Maybe the cooling air is blowing the oil from the oil pressure sensor onto # 3.

Dave

Posted by: kwales Sep 3 2005, 09:12 AM

Dominic,

Not good to retourque just the upper head nuts, These aircooled engines require a specific cross torquing sequence on ALL the head nuts on one side. Tightening the upper head nuts will unbalance the head/cylinder clamping force and at worst case, cause a head leak or oval a bearing in the engine. That is, the clamp force on the upper side is probably higher on the top than the bottom.

I am extremely anal in head torquing- a bunch of old VW autocross guys taught me. I use the cross pattern torquing sequence but unlike the manual, do both sides of the engine and do it in 5in/lb increments. That is, if I start on one head nut, I torque to 5 in/lb then I go to the opposing side of the engine and torque the exact opposing head nut on the other side to 5 in/lb. Then back to the first side and next nut.... and back to the second side ....and first side... and second side..

Takes me a while going back and forth but never had any problems later. The guys that taught me built a 176 hp (at the rear wheels) bug engine for autocross.

Ken

Posted by: Dominic L Sep 3 2005, 09:29 AM

QUOTE (kwales @ Sep 3 2005, 07:12 AM)
Dominic,

Not good to retourque just the upper head nuts, These aircooled engines require a specific cross torquing sequence on ALL the head nuts on one side. Tightening the upper head nuts will unbalance the head/cylinder clamping force and at worst case, cause a head leak or oval a bearing in the engine. That is, the clamp force on the upper side is probably higher on the top than the bottom.

I am extremely anal in head torquing- a bunch of old VW autocross guys taught me. I use the cross pattern torquing sequence but unlike the manual, do both sides of the engine and do it in 5in/lb increments. That is, if I start on one head nut, I torque to 5 in/lb then I go to the opposing side of the engine and torque the exact opposing head nut on the other side to 5 in/lb. Then back to the first side and next nut.... and back to the second side ....and first side... and second side..

Takes me a while going back and forth but never had any problems later. The guys that taught me built a 176 hp (at the rear wheels) bug engine for autocross.

Ken

Uh oh! So that's probably why since i did that I'm getting puff's of exhaust pulsing in the area. Thanks for the tip. I'll redo all the head nuts and see what happens.

Btw Dave, the plugs read fine on all cylinders. Definitely no oil fouling. Guess I'll just keep looking till i find it. Going under the car now.

Thanks again,
Dominic

Posted by: kwales Sep 3 2005, 10:12 AM

Have a Haynes manual? It has the torquing sequence and it's not cross torquing per cylinder (like a wheel ) but rather cross torquing in a funky sequence across each head. Any aircooled vw engine uses the same sequence so if you have a VW manual, go for it.

Not sure if your engine has head gaskets or not. Might want to pull the retorqued head and look to see if they leak.

Big battle here on whether to use them or not. If you use them, make sure they are on both sides. If they are there, prolly easiest to keep using them (unless the head is pitted). That way you won't have to screw with valvetrain geometry.

Ken