• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Progress-new thread Monday

Share this page

I used to use dye check for cracks. You applied red dye to the parts and than wiped it off. Than you sprayed on a white power coating, looked like you painted the part with white paint and it sucked the red dye out of the cracks leaving red lines that were easy to spot. In your case it should be yellow or black on white.
 
I was wondering Jack. Was this engine line-bored or was the crank ground? Reason is that line-boring can cut the scroll seal part of the rear main cap. They shouldn't but an over zeleous machinist could. Or, if the crank was ground, he might also grind the seal section of the crank. Either way, even if the top scroll seal is positioned properly, the bearing cap is not adjustable and there will still be too much space on the scroll part of the bearing cap. See the picture of how startech47 built up his on page 11 of this thread.
 
I agree with Donn's comments, if block or crank work has been performed since the engine ran without leaks. This also applies to my comments on the direction of knurling of the crankshaft.
 
Block was not line bored nor was crank ground, It is still standard standard.

Bottom of the eyebrow is orginal, has never been touched by anything. I got something stupid, I'll find it.

I did note your comment "Some cranks were set up for reverse rotation and if used in the wrong engine they will pump the oil out of the engine."

Anyone have a clue what these might have been?
 
As I understand it, before you changed the oil pump and bearings, you didn't have this oil leak. You are running the same crank/ scroll setup that you had then so I don't think direction of rotation comes into play. What has changed is oil pressure. I think you have a pressure related leak. Maybe a galley plug or, and this is what I would look close at, the oil pump cover. Look for a pinhole or a warped flange where it mates with the gasket. I think when you find the problem it will be obvious. Just not looking in the right place yet.
 
The amount of oil you are losing does sound like a pressurized oil leak. I forgot the oil pump is on the back of the block. Check there as well and take pictures.
 
You guys are correct of course. Good call.

I wonder, I just wonder if that soddered cover has a fine crack in it that causes it to leak under pressure. I know the pump is sealed in good and I know the plate is sealed to the block well, but I wonder.

Had to cut a bit off the back of the pump to make it fit under the corner of the plate, the new pumps it seems are a bit too high or wide or what ever. I wonder.

I have a friend who is sending me a backing plate with the can brazed on. Hmmmm, think I will use that one instead just in case.
 
Are all of those covers supposed to be "brazed"? I think I just put mine into place.... /bcforum/images/%%GRAEMLIN_URL%%/frown.gif If anything, I used a little gasket sealer......?
 
On the 948 they are soddered at the factory. The final solution is to braze. On the 1275 they are not fixed, just a bit of sealer as you did.
 
You know I do remember eyeballing that pump cover as best I can with these old eyes. I will check with my magnifying glass as well.

You know the more I think on this the more I wonder and think it is a strong possibility. There is a drain hole in the back of the pump housing but I wonder if it can handle 60 lbs of oil pressure. That would be a bit of volumn I would expect. Remember the backs of these pumps are only held on with a few bolts and no seal or what ever just alum to alum. I wonder if that joint between the pump body and the cover should have a bit of stuff in in it as it is assembled as well.
 
Had to cut a bit off the back of the pump to make it fit under the corner of the plate, the new pumps it seems are a bit too high or wide or what ever. I wonder.
Jack I had the same problem. Could it be that maybe not enough material was removed and after tighten everything to gather there is some stress on the can and it pulls away enough to allow oil to pass by? A small crack or distortion @ 60 lbs oil pressure on a 2.2 – 3” circle ends up being quite a bit of force you would loose copuis amounts of oil. Just a thought
 
Jack

Do you have the gasket between the oil pump and block?

Mark
 
Yes there is a gasket between the oil pump and the block along with RTV.

<span style="color: #FF0000">Texas Bugeye, Chris, has come to the same conclusion that I have.</span>

Now I am most ancious to open her up and find out.

Will start later today in any case, too durn cold out there now.
 
Open her up Jack

Yes the back plates and new oil pumps do not fit very well. I had to grind some material off the pump in order to get a good fit.

Mark
 
I might not have ground enough from the pump and have a bit of stress when the backing plate/can is bolted down. As a matter of fact I would not be susprised if I had cracked the sodder when bolting the backing plate in. So it is maybe cracked from the stress and in fact held open a bit from the pump.

At least that is my story and I think I will stick with it untill I see otherwise.
 
jlaird said:
Will start later today in any case, too durn cold out there now.
Click to expand...

Harummph - I just finished shoveling the driveway - you? /bcforum/images/%%GRAEMLIN_URL%%/wall.gif /bcforum/images/%%GRAEMLIN_URL%%/grin.gif
 
Cold (for us down here!) Yes /bcforum/images/%%GRAEMLIN_URL%%/eek.gif ! (55* here in S. Fla. but down to the mid-30s, I'll bet, up where Jack is!), but no driveway shoveling for us anymore!! /bcforum/images/%%GRAEMLIN_URL%%/thumbsup.gif

Jack, it should be good to go by this afternoon, warm enough to work and cool enough not to work up a sweat!! /bcforum/images/%%GRAEMLIN_URL%%/jester.gif /bcforum/images/%%GRAEMLIN_URL%%/thumbsup.gif
 
Yep, for sure.
 
Ok, ready to lift the engine. Takeing a break, that is tough on old backs.
 
Back
Top