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Topic Summary

Posted by: PeterL
« on: June 08, 2016, 03:44:47 PM »

If the bores are indeed round as he said, sleeving and grinding is pretty normal.  Honestly, whats not normal is for the housing (cam bores) to be "round" if they are worn.  Let me know how it works out!
Posted by: JimVillers
« on: May 27, 2016, 12:04:09 PM »

Six weeks later and I am still waiting for my block to be repaired.  When it left the "in waiting" area, the machinist changed his approach.  He felt that since the holes in the block were very round, he decided to do the machining on the camshaft.  He ground down the cam bearings, sleeved the cam bearings to increase their size and then grind down the cam bearings to fit the block.  He said that it was easier to accurately ground down the cam to fit the block than bush the block to fit the cam. 

As you said, there are several approaches to solve the problem.  I'll report oil pressure when the engine is assembled and running.
Posted by: JimVillers
« on: April 26, 2016, 08:46:15 AM »

Peter .... I have great confidence in the shop.  They normally work on vintage race engines but also do the one off type of stuff that we hobbyist drag in.  They have all of the fancy stuff like a flow bench for tuning the head to a stationary dyno to run and tune engines before installing them into the car.  There is just not time on the track to break in an engine.
Posted by: PeterL
« on: April 25, 2016, 09:54:44 PM »

Cool beans, if they have a history of that type of repair I am all for it.  I only made my recommendations on the basis that the machine shop had not made a similar repair before. 

Good luck!!
Posted by: JimVillers
« on: April 25, 2016, 02:42:20 PM »

Peter ..... Just to provide an update.� We first tried a new cam shaft to see if that might provide a solution.� It picked up a thousandth or two but not enough t get close to the specification.� The block is being sent to another shop to have the journals bored and bronze bushings installed.� They are using bronze because that is what they are familiar with and what they used on a similar jobs on old Triumph engine.

Posted by: PeterL
« on: April 19, 2016, 07:33:13 PM »

Glad I could help.  I am a Reliability Engineer, essentially my whole job is to systematically pick apart things to find out how/why they failed and how to eliminate that mode of failure.  I did not want to pull my engine this summer and not know what I was getting into, so I thought long and hard since October about what the problem could be.  I am glad that you have confirmed the problem.
Again, there are a bunch of different ways to repair it. I myself like simple/straight forward approaches.  I strongly feel that cast iron sleeves shrunk in with Liquid Nitrogen are the best most cost effective solution.  Keep in mind yes, for years and years interference bushings were pounded in with a hammer but, liquid nitrogen will keep the fit concentric and ensures you that the oil port will line up exactly where it needs to go.  Oh and one last thing, you can get one hell of an interference fit (they will never come loose EVER).

 Keep me informed on what they do for the repair!

Peter
Posted by: JimVillers
« on: April 19, 2016, 06:01:02 PM »

Peter ..... It looks like you were spot on.  The cam bearings were VERY loose, .005-.007 or so.  I attached the specifications which show it should have about .001 clearance for the oil film. 

It was good that I pulled the engine, the bearings were already showing some wear from metal-to-metal contact. 

I'll post the fix when my machinist decides on what he will do.
Posted by: JimVillers
« on: April 10, 2016, 08:07:45 PM »

Peter .... Thanks; I'll visit my machinist tomorrow to decide on a repair plan.  I'll update your when I learn something.
Posted by: PeterL
« on: April 10, 2016, 06:31:13 PM »

Another piece to think about.  When you do research you can find references on the web Cj2A website and other places on how to install a bearing into this location.  It is possible but, if you do find you need this repair I recommend a different repair.  Have your machine shop line bore the 2,3rd, and rear bearing housings to accommodate new cast iron bushings.  They are cheep $15 or less each and you can predrill the hole for the oil port.  The labor to perform the task will be less than trying to retrofit a bearing assembly.  If the machine shop does it right and sets the bushing up with a 0.001-0.002" (OD) interference fit and they shrink it with liquid nitrogen, it will slip right in and within seconds it will warm up.  No locktite, no beating with a hammer, and no special pulling tools in awkward positions and it WILL NOT come out.  The fits will be restored to factory, with the same material, fit, and finish.

This is the company I used to use when repairing bearing fits in my old shop.

http://shaverkudell.ca/wp/products/eze-sleeves-list/the-original-cast-iron-series

-Peter
Posted by: JimVillers
« on: April 09, 2016, 12:53:32 PM »

Peter .... Thanks you; an idea and logic that I had not though about.� I will stop by the machine shop on Monday and look at the rear cam "bearing".� It is one of the few items that we have not measured or investigated.�

Finally someone who has experienced the same problem.  There is nothing new with these old engines, only "old" problems that we have not heard about.  I'll post what I find.
Posted by: PeterL
« on: April 09, 2016, 12:17:22 PM »

Sorry computer glitch- My thoughts continued.

One thing to remember, oil pressure does not equal flow.  I believe I have enough oil flowing.  But somewhere in the system there is a gap that would have gone un-repaired or un-machined during my rebuild.  The only thing that fits this would be the rear Camshaft housing at the rear of the block.  The front housing contains a bearing and is easily repaired by boring and bushing.  However, the rear housing is cast iron and a part of the block.  It is not easily repaired.  This is likely the only thing, due to location and a lack of replacement parts that was left untouched. When did measure it it was .006-.008 out of round.  I did not think this was too awful a the time but I am convinced that at low RPM there is enough bleed by to reduce the oil PSI to near 0.  While at 2k RPM the PSI is 22.  I would bet $100 bucks, that if that was bored and bushed to a 0.001-.002 tolerance my at idle PSI would be 20 ish and at 2k it would be 35-40 ish.

I would bet that you are dealing with the same issue.

Just my thoughts after thinking/checking on mine for the past year. 
Posted by: PeterL
« on: April 09, 2016, 12:06:15 PM »

I rebuilt my engine last year. I am going to yank it as soon as the weather stays above 50 degrees for more than a day.  I suspect the problem lies with the rear cam seat.  Why do I suspect this?
1) tried two different oil pumps - Same result
2) tried two different gauges - Same result
3) I used to work in a machine shop and I am confident it both my initial measurements and my final assembly measurments.
4) End-play was checked and rechecked upon disassembly.
5) I pulled the oil pan last year to check all the galley plugs - all installed
6) removed the front timing cover and inspected the aperture.  I had previously brazed and re-drilled a .040 hole.  I checked with a wire guage all OK.
Posted by: JimVillers
« on: April 03, 2016, 10:41:03 PM »

Hawk .... Good catch, my timing gear oil jet is larger than my largest gauge, 1.5mm (0.06 inches) so I must have a 0.07 jet.� Easy fix.

The end float is an interesting question, I'll measure it tomorrow.� I guess that the idea is that the #1 main lubricates the thrust bearing and if that is too loose, it will loose pressure.�

Oil-Leak .... I blocked off the oil line to the filter and it did not change the oil gauge readings. 

Great thought.� It may not be a single issue but a number of independent items.� I very much appreciate your (plural) comments.
Posted by: Oilleaker1
« on: April 03, 2016, 06:13:33 PM »

How much end float did you have on the crank? .002-.003 bearing clearance should not have caused your problem. You could try blocking off the oil filter feed to see if something is wrong with the canister. Two oil pumps with the same results means the relief valve is working or seated. Very strange you haven't found it. John
Posted by: athawk11
« on: April 03, 2016, 10:19:51 AM »