How worn down are my cam bearing caps

[96eighty]

Took the exhaust cam out yesterday and found my 7th cam bearing is very worn compared to the rest. The bolts holding it in we’re not as tight as the rest probably due to it being worn extra.

My question is, is this anything to be concerned about?

 

[Rusty Marlin]

There should a tolerance for the bearing, measured with plasti-gage.
I haven't done one on the cruiser yet but it was easy to do on the Camry.

Just looked, its in the FSM under Engine, Mechanical. For the 96 book it starts on page EM-45.

 

[96eighty]

There should a tolerance for the bearing, measured with plasti-gage.
I haven't done one on the cruiser yet but it was easy to do on the Camry.

Just looked, its in the FSM under Engine, Mechanical. For the 96 book it starts on page EM-45.

Thanks, I’ll refer back to it when I get home.

If it’s out of spec, I’m guessing I need new caps..?

 

[Rusty Marlin]

No. You can't replace the caps, they are line bored as an assembly with the head.
It will be new cams or a new head or both.
You are looking for oil clearance through a gap. If the gap is too much there won't be the proper film of lube to support the cam shaft while spinning.
Theoretically you could increase the weight of oil to support the larger gap, but that's true for any older engine with worn journal bearings.

 

[96eighty]

There should a tolerance for the bearing, measured with plasti-gage.
I haven't done one on the cruiser yet but it was easy to do on the Camry.

Just looked, its in the FSM under Engine, Mechanical. For the 96 book it starts on page EM-45.

Do you mean the EG tab under mechanical? My LX repair manual shows this page.

Edit:
*On the LX repair manual it’s on EG-36 & 37

 

[Rusty Marlin]

Looks the same as mine, just different page numbers for different format.
I have a digital copy:

Do you have .0001" micrometers to inspect the cam shaft? You need a set of 1-2's
Amazon product ASIN B003UATB7K

 

[Rusty Marlin]

In the area outlined the finish looks a little "off"; but the surface isn't scored or flaking. Doesn't look like anything got dragged through the journal.
Follow the FSM for inspections. If it all checks out, reassemble the beastie.

I don't know how experienced you are, so if this advise is unwarranted just tell me you've got this:
Don't forget to use an assembly lube on the journals and cams before putting the cam shaft in the bearings.
After assembly and before the first start-up, keep the spark plugs out and crank the engine over until you see oil flowing in the head while looking in the valve cover.
This ensures the journals are lubricated and ready to go before starting.

 

[Malleus]

I know photos are hard to use for something like this, but how exactly do you know your bearing is "worn"? I can't see the difference, in your photos. Loose bearing cap bolts aren't a "sure" sign your bearing is worn. Also, which one is #7?

 

[96eighty]

Looks the same as mine, just different page numbers for different format.
I have a digital copy:
View attachment 3104098
Do you have .0001" micrometers to inspect the cam shaft? You need a set of 1-2's
Amazon product ASIN B003UATB7K

I don’t have one unfortunately, and I don’t think auto one has a rental for it either.

View attachment 3104099

In the area outlined the finish looks a little "off"; but the surface isn't scored or flaking. Doesn't look like anything got dragged through the journal.
Follow the FSM for inspections. If it all checks out, reassemble the beastie.

I don't know how experienced you are, so if this advise is unwarranted just tell me you've got this:
Don't forget to use an assembly lube on the journals and cams before putting the cam shaft in the bearings.
After assembly and before the first start-up, keep the spark plugs out and crank the engine over until you see oil flowing in the head while looking in the valve cover.
This ensures the journals are lubricated and ready to go before starting.

I really appreciate the advice!! I’ll definitely do that. I wasn’t able to use plastiguage yet but I’ll do it after I get it back from the machine shop.

Had to get help at 3am in the morning to lift the head to place it on 2x4s to fish the wire harness out and am wanting to get a lot done before school starts back up.

I really, really thankful for mudders like yourself giving newbies like myself good info on what needs to be done.

I know photos are hard to use for something like this, but how exactly do you know your bearing is "worn"? I can't see the difference, in your photos. Loose bearing cap bolts aren't a "sure" sign your bearing is worn. Also, which one is #7?

#7 is the farthest one on the right. Basically the grove on the bearing seems pretty worn down compared to the rest

 

[mudgudgeon]

#7 is the farthest one on the right. Basically the grove on the bearing seems pretty worn down compared to the rest

I agree, this looks suspect. Only way to know for sure is measure the cam journal and measure the internal bore diameter of the head/cap journals with telescopic micrometre, or plastigage.

If wear is uneven, plastigage may not give you the full picture

 

[Malleus]

I don't know of anyone who'll rent a tenths mic.

 

[96eighty]

I agree, this looks suspect. Only way to know for sure is measure the cam journal and measure the internal bore diameter of the head/cap journals with telescopic micrometre, or plastigage.

If wear is uneven, plastigage may not give you the full picture

I'm guessing this is something I should have the machine shop do?