The Stovebolt Page Forums Home | FAQ | Forum | Swap Meet | Gallery | Tech Tips | Events | Features | Search | Hoo-Ya Shop
Helping out ...


EVENTS

Check in for status!

Jump over to the Events Forum, to post events -- new ones or the ones we have been enjoying for some time.
Look to see what's been cancelled or postponed.

Encourage one another!

Stovebolt Site Search
 
Old Truck Calendars
Months of truck photos!
Nothing like an old truck calendar

Stovebolt Calendars

Check for details!


Who's Online Now
12 members (Dusty53, Greg_H, DS1957GMC, Forty9, 2 invisible), 178 guests, and 3 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums50
Topics120,958
Posts969,662
Members43,802
Most Online1,229
Jan 21st, 2020
Image Posting Policy
Previous Thread
Next Thread
Print Thread
Page 1 of 6 1 2 3 4 5 6
Low Oil Pressure ‘59 235
#1370993 Tue Jul 28 2020 12:54 PM
Joined: Feb 2019
Posts: 835
P
Phak1 Offline OP
AD Addict
For those of you that don’t know, I have been chasing a low oil pressure for about a year now. It runs about 35 lbs when I first start it to below 5 lbs. at idle when It heats up. I had the opportunity to speak to the gentleman that had the engine rebuilt about six years ago and he told me that it destroyed a main bearing right after he got it back from the machine shop. They told him that the clearances were a little too tight so they added a thousand shim. Since then he also experienced low oil pressure. The engine since the rebuild does not have 100 miles on it.

I finally pulled the engine and here is what I found under the main bearing caps. The first shim under the rear main is not .001” thick but .009”.

I was anticipating having to pull out a small shim but when I encountered the .009” shim that has me perplexed. I would seem to me if they needed a little more, why would they put a .009” shim in? At this point, I believe I have to pull the crank and get proper mic readings. That way it will tell me if the bores are out of round from the shim and what the actual clearances are.

Can I pull the crank without pulling the pistons? I have not pulled the head as of yet trying to cut down on the amount of work but now I’m thinking I may have to.

It also brings up another question. If the shim raises the bearing cap by .009”, does it also separate the bearing shells by the same? Wouldn’t that create a leak path?

The other issue I encountered was the area where the rear main seal rides on the crank is pitted. Do they make a SS sleeve to fix that?

Attached Files
36D49801-5302-4906-B06E-2C99EB9142F4.jpeg (204.89 KB, 242 downloads)
4BCC3F55-E2B8-4F58-8ADC-365CEFF05F06.jpeg (289.37 KB, 241 downloads)
7B57D6F6-6457-4BDA-9CFD-5627A7FA3D71.jpeg (192.48 KB, 235 downloads)
Last edited by Phak1; Tue Jul 28 2020 01:03 PM.

Phil

1952 Chevrolet 3100
Project Journals
‘59 235 & hydraulic lifters
“Three on the Tree” & 4:11 torque tube
12v w/ Alternator
Re: Low Oil Pressure ‘59 235
Phak1 #1370999 Tue Jul 28 2020 01:33 PM
Joined: Mar 2014
Posts: 1,651
J
Shop Shark
Hi Phil,
Well, a couple of things. First, yes there is a speedi-sleeve that will fit the crank end. Jerry knows the part number and I'm certain he'll comment on your question. It will allow you to use the neoprene seal (which in this year engine ought to be a better answer for you by a long shot). Next...whoever it was that did the work on this engine should be avoided. Something went plenty wrong here. Take a look at the first image you attached. The bearing in there is worn more oddly than I believe I've ever seen. Unless there's a terrific optical illusion going on, it tapers from rear of engine to front by what appears to be about 2mm and it seems to sit up in the back off of the cap. That (unless this is a weird illusion) is a very serious mistake. You can pull the crank without pulling the pistons. Get 12 pieces of thin rubber tubing cut about 1.5 inches long that will fit over the rod bolts (so you don't nick the crank in the process), remove nuts and rod caps and push them up and out of the way. But either way you need to get that crank out and to a machine shop where the people don't drink all day. I think you need to have it checked for size and reground and install new main bearings. You also need to check the rod bearings. What is going on with that bearing we can see I could only guess, but that isn't good. No shims should be used on new bearings. What you need is to have the crank ground so that the gap between the crank and bearings will be .001". At the most, I'd say .0015" but lean on the machinist to get it to .001" and your oil pressure problem should be greatly improved. Of course we don't know what they did with the cam bearings, but hopefully not what they did with the lower end. As for your question of the .009" shim, the answer is that is wrong from every possible angle. And we don't know what they did to the bearing to make this fit together, but yes...it could create a problem oil path...not to mention other things. I doubt the main bearing bores will be out. Good luck and please keep us posted.


Jon

1952 1/2 ton with 1959 235
T5 with 3.07 rear end
Re: Low Oil Pressure ‘59 235
Phak1 #1371000 Tue Jul 28 2020 01:48 PM
Joined: Mar 2014
Posts: 1,651
J
Shop Shark
Wait a minute...the shim is causing that bearing to appear oddly worn. That is causing the illusion. At first I could not see detail in the scan and thought this was gasket sealer, but what I'm seeing is the shim they made. They cut this one to match the entire surface of the cap on the rear main (but only on one side or is that a shim piece over to the left side of the image?) whereas on the other cap (in the third image) they just stuck some shim stock under the cap? Yes, that will create an oil path...plus the approach is very odd, don't you think? In the time it took to make that shim, they probably could have ground the crank correctly.


Jon

1952 1/2 ton with 1959 235
T5 with 3.07 rear end
Re: Low Oil Pressure ‘59 235
Phak1 #1371001 Tue Jul 28 2020 02:19 PM
Joined: Feb 2019
Posts: 835
P
Phak1 Offline OP
AD Addict
The cap does have two shims. They appear to be pre-cut and not home made. The second shim is in the first picture on the table to the left. Thanks Jon for the tip on pulling the crank. It will be a couple of days before I get back to it as it’s my grandson’s birthday.

Look’s like I need a recommendation for a machine shop near Albany NY.


Phil

1952 Chevrolet 3100
Project Journals
‘59 235 & hydraulic lifters
“Three on the Tree” & 4:11 torque tube
12v w/ Alternator
Re: Low Oil Pressure ‘59 235
Phak1 #1371005 Tue Jul 28 2020 03:01 PM
Joined: Mar 2014
Posts: 1,651
J
Shop Shark
Thanks Phil, your grandson's birthday is more important. Hope somebody here will know of a good machine shop up your way. I looked on Amazon and they still sell the rod bolt covers. Interesting. Used to you had to buy these in a pair and they were yellow. I have a pair which I've had since the 60s.
https://www.amazon.com/Goodson-Rod-Bolt-Protectors-16/dp/B0009RH412


Jon

1952 1/2 ton with 1959 235
T5 with 3.07 rear end
Re: Low Oil Pressure ‘59 235
Phak1 #1371007 Tue Jul 28 2020 03:12 PM
Joined: Feb 2004
Posts: 21,014
H
Boltergeist
They put an entire shim pack between the block and the cap. If you examine those shims carefully, you'll find that they're composed of a stack of .0005" layers. If you use a box cutter blade or an X-acto knife you can peel them apart and adjust the clearance properly. Start by cutting a small bit of one corner away with tin snips, then use a sharp knife to peel the layers apart at the cut you just made. I prefer to set bearing clearance with a narrow piece of .0015" shim stock (about 1/4" wide) between the bearing and the crankshaft instead of Plastigauge. Start with no shims at all between the cap and the block, which will lock the crankshaft. Start adding shims between the cap and the block in .0005" steps until the crank can be turned with just a bit of effort by pulling on the flywheel. Don't forget to remove the checking shim! It's acceptable to make a 1-layer difference from side to side to fine-tune the clearance. Check ALL the main bearings the same way- - - -anyone who made a blunder like you've found already has probably made a bunch more errors!

Pulling a crankshaft with the engine in the vehicle is a huge pain in the derriere because the separator plate between the block and the timing cover keeps the crank snout from dropping more than a half inch or so. You'll have to remove a bunch of stuff, including the camshaft and the crankshaft timing gear to get that plate off. I'd prefer to pull the engine. 3/8" ID rubber fuel hose makes an excellent rod bolt cushion, and they sell it at every local parts store.
Jerry


The murder victim was drowned in a bathtub full of Rice Krispies and milk.
The coroner blamed the crime on a cereal killer!

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
Re: Low Oil Pressure ‘59 235
Phak1 #1371009 Tue Jul 28 2020 03:24 PM
Joined: Dec 2017
Posts: 807
D
Shop Shark
The 59 should not need shims at all. Shims were 55 and earlier motors that used the rope seal and a different style of bearings. Really there should be no reason to shim the bearings on a fresh 59 to get to proper clearance. Someone simply did not want to make the needed correction and decided that good enough was good enough. What a disgrace. So there are a couple of things you might consider here. First, if you are taking the motor apart, have the block check for main alignment. These motors are not known for having the mains out of alignment but every once in a while you come across one that is really out of wack. The thing is that aligning the mains on one of these motors is not like aligning the mains on a small block chevy in that the procedure for a 235 is more complicated then usual because each of the mains is a different size and requires setting up the cutting bar for each main. That and moving the clearances around can sometimes play havoc with the gear teeth clearance on the timing gears and the neoprene rear main seal will now also need modification. So check it and if its within a normal range, go with it because but you really don't want to go down that road if possible (expense and work wise).

As for the bearings, if you flip the bearing shell around you might be able to pick up a part number and that part number will tell you if the crank was ground undersized at some point. If so, you might consider getting the next size bearing and then get yourself to a good machine shop. The right way t do this is to install the bearings and tighten the main caps. Then you measure the id. Subtract whatever clearance you want, .001, .015, and that is the size you machine the crank to. Now you have some accuracy on the machine work. As you have determined, the wider clearances have a negative effect on oil pressure. A lot of race cars build that excessive clearance into their builds to reduce parasitic drag. But they change the standard volume pressure pumps to some more to take up the pressure bleeding off for the larger clearances. A 235 does not need that at all so I think if you can get the bearings and crank clearances sorted out, you will find a much better pressure situation going forward.

Last edited by Dragsix; Tue Jul 28 2020 03:27 PM.

Mike
Re: Low Oil Pressure ‘59 235
Phak1 #1371011 Tue Jul 28 2020 03:32 PM
Joined: Feb 2004
Posts: 21,014
H
Boltergeist
My line bore machine has spaces for several cutter bits. I set up four cutters to the appropriate diameters, and make all the cuts in one pass. The trick with timing gear tooth gullet clearance is to make only a .001" to .002" cut into the block and take most of the material out of the caps. Set up the boring bar exactly concentric with the bearing bores at both ends of the block, lower the bar slightly so the cutters just barely scratch the block, and machine .010" off the mating surface of the caps. When the cut is made, the holes end up round, in line, and the right diameter, and the bearing caps don't care if they're a little shorter.

Most people who pontificate about line boring have never actually done it.
Jerry


The murder victim was drowned in a bathtub full of Rice Krispies and milk.
The coroner blamed the crime on a cereal killer!

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
Re: Low Oil Pressure ‘59 235
Phak1 #1371047 Tue Jul 28 2020 08:39 PM
Joined: Feb 2019
Posts: 835
P
Phak1 Offline OP
AD Addict
Thanks for all of your advice. As soon as I can, I’ll pull the crank and mic up all of the clearances to see what I have and report my findings.


Phil

1952 Chevrolet 3100
Project Journals
‘59 235 & hydraulic lifters
“Three on the Tree” & 4:11 torque tube
12v w/ Alternator
Re: Low Oil Pressure ‘59 235
Phak1 #1371058 Tue Jul 28 2020 09:21 PM
Joined: Dec 2017
Posts: 807
D
Shop Shark
That is an interesting comment because I have not personally machined the main bore of a block as I am not a machinist. But, like most others, I have had to have a machinist do the work for me. And yes, and I have had to line bore a block (two of them actually, both 261s which is why I went to the trouble and expense) and the truth is that most machinists don't want to be bothered. Its just not that profitable for them and it takes a lot of set up time to get it right. I know exactly how much time it takes in that quite a few years ago now, I watched Jimmy Fox at the now long defunct K&G Machine Shop in Havertown PA (Mr. Fox was the Fox of Frantic Ford funny car fame) do the set up for one of my 261 blocks. Was probably around 88 or 89 or so. I am not even sure Mr. Fox is still living. What I can say is that he had great patience for my project. It was my first early style motor line bore and taught me a valuable lesson, the expense may not be worth it. If you are lucky enough to find a machinist who is willing to take on the job, its expensive. More expensive then just replacing the block when all is said and done. Can it be done, yes it can. Is it worth it, usually no. In my view, a 59 235 that is so out of line you need to re-bore the mains straight is financially more likely a candidate to just be replaced. That is my experience any how.


Mike
Page 1 of 6 1 2 3 4 5 6

Moderated by  Woogeroo 

Link Copied to Clipboard
Home | FAQ | Forum | Swap Meet | Gallery | Tech Tips | Events | Features | Search | Hoo-Ya Shop
Powered by UBB.threads™ PHP Forum Software 7.7.4