Oil Pump Shims

[John76]

Is there a limit to the number of oil pump shims you can use before replacing a stretched oil pump chain?

 

My original '76 came with 2 x 0.004" shims and was starting to make noise at start-up when the oil pressure was highest.

The slack side of the chain was just barely starting to leave witness marks on the pressure relief casting at 143K miles.

I installed 2 x 0.012" shims (thank you @Mark92131!!!) in place of the 2 x 0.004's, but still have more than the recommended 5mm "slop", however there is no contact with the casting.

Should I continue to add the 0.004" shims until the chain is to spec?  Or go to the hassle of removing the front pulley and cover to install a new chain?

Any left-over shims will be available to whomever needs them...NO CHARGE.  

Thanks,

John

 

 

 

[JsnPpp]

I just went through this with mine. Wound up needing two 0.1mm shims to bring it to "right" tension (1-2mm play)?

 

I read many threads on this, one of them discussed concerns on whether there was a limit to shims before it 1. hit the bottom of the pan and 2. pulled away from the o-ring. My memory says the decision was that those won't happen any time soon (please reread to make sure).

 

There are multiple examples of folks using "two thick and two thin". Thin is 0.1mm, thick is 0.3 mm.

 

I'd add at least another 0.1 shim. It doesn't take much for that chain to snug up.

 

Many others here rebuild engines much more often than me and so may have other guidance. Hope this helps!

[jimk]

A note of caution - a well worn chain will wear the sprocket teeth.

 

So a penny spent might save a dollar.

Or an ounce of prevention can often save a pound of cure.

Edited March 20 by jimk

[Son of Marty]

Check the side play on your chain, on a worn chain you'll see quite a bit movement between the links and rivets.

[Dudeland]

I replaced my oil pump, chain and sprocket when I did my oil pan.  It was a "while I was there decision".  At 143K miles, I would roll the dice and put some more shims in it,  just make sure they don't get crunched when you put them in.    Test your oil pressure light circuit just in case.

 

Regards 

 

 

 

[John76]

Thanks everyone for feedback.

My bad for not using the search box feature on our forum ... duh, the answer to my question was right there!!

[John76]

On 3/20/2024 at 12:07 PM, JsnPpp said:

There are multiple examples of folks using "two thick and two thin". Thin is 0.1mm, thick is 0.3 mm.

I used two thick (0.3mm ea.) and one thin (0.1mm) with my original chain to achieve a "just right" deflection.

Factory shims were two thin (2 x 0.1mm).

Not too tight, and not too loose...does not come close to rubbing the pressure relief tube.

I have one thin (0.1mm) shim for anyone who needs it. PM me and I'll be glad to send it.

John

BTW: What do you use to pre-fill the oil pump? Some say pack the rotor cavity with a light grease.  How light??

 

 

[NickVyse]

When possible I always prime the pump and engine with a pot of oil with the sprocket off - hook up an idiot light from the sensor and you know you have pressure before installing. It actually takes quite a bit more oil than shown in this vid as I buggered up the start - here's a pic of the amount of oil I started with.

 

 

 

 

[jimk]

Hold the chain against the sprocket at 3 and 9 o'clock and if the chain pulls away from the sprocket at 6 o'clock, it's time for a new one.

[JsnPpp]

I hsven't addressed this yet on my motor. In my head I was thinking I would remove spark plugs  and run the starter until pressure light turned off. If this is a bad idea let me know!

 

Also my chain is tighter than that. Probably it was what yours is now and then I snugged it up. I'm not saying thats what you should do I'm sure I over thought it.

 

I'm months away from running the car but motor is in now and so it makes it harder to make "chain"ges. 🙂 

Edited March 22 by JsnPpp