Engine build question 52 Cranbrook 218

[DJK]

Just got my engine back from machine shop, bored .020 over, crank polished, block cleaned, valves and seats refaced, head resurfaced. Checked the crank, main journals measure 2.50(on spec), rod journals measure 2.062(on spec). Using green plastigauge (.001-.003) I have .003 clearance on mains and rods, specs are .0005-.0015. There are no indications on the crank center throw to indicate other than std. bearings are required. What to do??? On another note, I checked my ring end gaps = .005, specs are .010-.020, looks like some filing is needed!!! Thanks in advance for any assistance.

[Sniper]

If the rod and main journals are in spec but the clearance is too much then either you are not using the plastigauge properly or your bearings are out of spec. 

 

Personally, I use micrometers to do this as they are way more accurate.  If you have them remeasure.

[kencombs]

Agree with Sniper.  The other possibility is the plastigauge paper gauge is inaccurate. Is it the brand name, or a generic?  Not that I'd suspect an offshore product of not being perfect, but...

[keithb7]

For what it's worth, recently I could not source .010 rod bearings. My crank surfaces looked pretty darn good. I found .001 bearings to be used for a crank polish. So I went with those and am only having my crank polished. 

 

I have been informed a way to measure clearances is to first mic the crank journal. Then Install the bearings in the rod end and cap. Install cap and torque to spec, (with the rod properly secured in a rod vice). Then a snap-T gauge and a micrometer, or better yet a dial bore gauge is used to measure the ID of the assembled, crushed bearing, when not installed on to the crank. Compare measurements of torqued, crushed rod bearing ID to crank journal OD.

Edited April 10, 2021 by keithb7

[Dave72dt]

You'll note in the manual it uses feeler gauge stock.  I suggest investing in and destroying an actual feeler gauge and measuring the way described.  I think you'll find the clearance you have and the suggested drag amount as you move the rod side to side will match up.  I doubt Plastigauge was around at the time.  The other question is how straight is the block and how straight is the crank?  You'll need that variance if either or both are not 100 % true.  You can have the mains and rods resized if you want the specs tightened up or maybe you can find .001 bearings.

 

As for ring end gaps, call the machine shop.  Because piston and ring compounds have changed over the years the specs for those gaps may have changed as well. .010 sounds like the gap for cast iron rings and that's probably not what you have now.

 

JMO.  Lots of ways to build and what one builder may be comfortable with for specs may not be for others or for the application the engine will be used in.   There have been a number of failures on rebuilds here on the forum, not a lot, but some, never the less, and I'd be a lot more comfortable with clearance on the loose end of the spec than on the tight.

[DJK]

6 hours ago, Sniper said:

If the rod and main journals are in spec but the clearance is too much then either you are not using the plastigauge properly or your bearings are out of spec. 

 

Personally, I use micrometers to do this as they are way more accurate.  If you have them remeasure.

I install the plastigauge(sealed power brand) torque main caps to 85# and rod caps to 45#. The main bearings were sealed in shrink wrap and looked perfect, the rod bearings looked like they were dropped in the ocean and stomped on!!! I can measure the crank = mains 2.50 and rods 2.062 just what the manual calls for. We're talking .0005-.0015 clearance, unfortunately I don't have a gauge to measure ID accurately. Will call machine shop Mon. to see if he will take some measurements.

[DJK]

5 hours ago, kencombs said:

Agree with Sniper.  The other possibility is the plastigauge paper gauge is inaccurate. Is it the brand name, or a generic?  Not that I'd suspect an offshore product of not being perfect, but...

Sealed Power brand

[DJK]

5 hours ago, keithb7 said:

For what it's worth, recently I could not source .010 rod bearings. My crank surfaces looked pretty darn good. I found .001 bearings to be used for a crank polish. So I went with those and am only having my crank polished. 

 

I have been informed a way to measure clearances is to first mic the crank journal. Then Install the bearings in the rod end and cap. Install cap and torque to spec, (with the rod properly secured in a rod vice). Then a snap-T gauge and a micrometer, or better yet a dial bore gauge is used to measure the ID of the assembled, crushed bearing, when not installed on to the crank. Compare measurements of torqued, crushed rod bearing ID to crank journal OD.

My crank is right on specs- mains 2.50, rods 2.062. There are no indicator marks on the middle throw of the crank to signify anything other than std size from factory.(maybe the guy in charge of that forgot!!!) Where did you source your bearings from?

[DJK]

3 hours ago, Dave72dt said:

You'll note in the manual it uses feeler gauge stock.  I suggest investing in and destroying an actual feeler gauge and measuring the way described.  I think you'll find the clearance you have and the suggested drag amount as you move the rod side to side will match up.  I doubt Plastigauge was around at the time.  The other question is how straight is the block and how straight is the crank?  You'll need that variance if either or both are not 100 % true.  You can have the mains and rods resized if you want the specs tightened up or maybe you can find .001 bearings.

 

As for ring end gaps, call the machine shop.  Because piston and ring compounds have changed over the years the specs for those gaps may have changed as well. .010 sounds like the gap for cast iron rings and that's probably not what you have now.

 

JMO.  Lots of ways to build and what one builder may be comfortable with for specs may not be for others or for the application the engine will be used in.   There have been a number of failures on rebuilds here on the forum, not a lot, but some, never the less, and I'd be a lot more comfortable with clearance on the loose end of the spec than on the tight.

I would be very hesitant to perform this measurement as described in my manual on a freshly polished crank in fear of marking the crank and/or bearing. As far as plastigauge, I'm sure it wasn't around back then, but .0005 clearance is the same in a 1952 or a 2022 engine I would think, but again, this is my first vintage engine. The rings are cast iron.

[DJK]

Thanks guys for all the replies, I will call the machine shop on Mon. and see if he can help me out with the measurements.

[keithb7]

1 hour ago, DJK said:

My crank is right on specs- mains 2.50, rods 2.062. There are no indicator marks on the middle throw of the crank to signify anything other than std size from factory.(maybe the guy in charge of that forgot!!!) Where did you source your bearings from?

 

Yes I agree your crank is in spec. However, the ID measurement on the bearing halves, after the cap is mounted, torqued, bearing crushed is the one you also need. A trickier number to measure. I found NOS 0.001 bearings on E-Bay. 

 

See here. Maybe contact the seller. I see he has lots more engine bearings for sale including a .002 set. Might be perfect for you.

 

https://www.ebay.com/sch/73revordnal/m.html?_nkw=&_armrs=1&_ipg=&_from=

 

 

[Dave72dt]

4 hours ago, DJK said:

I would be very hesitant to perform this measurement as described in my manual on a freshly polished crank in fear of marking the crank and/or bearing. As far as plastigauge, I'm sure it wasn't around back then, but .0005 clearance is the same in a 1952 or a 2022 engine I would think, but again, this is my first vintage engine. The rings are cast iron.

I normally wouldn't measure clearance that way either but I also wouldn't have been that concerned with a .003 clearance either.   I'm merely suggesting that the feeler gauge method may be deceiving in the actual clearance measured with more modern methods.  Being able to move the rod side to side means there is more actual clearance, perhaps as much as an additional .001.   A true .0015 would have the rod locked in place.

[DJK]

10 hours ago, keithb7 said:

 

Yes I agree your crank is in spec. However, the ID measurement on the bearing halves, after the cap is mounted, torqued, bearing crushed is the one you also need. A trickier number to measure. I found NOS 0.001 bearings on E-Bay. 

 

See here. Maybe contact the seller. I see he has lots more engine bearings for sale including a .002 set. Might be perfect for you.

 

https://www.ebay.com/sch/73revordnal/m.html?_nkw=&_armrs=1&_ipg=&_from=

 

 

Thank you for the info.

[Sniper]

When you used that plastigauge did you cut a piece off or tear it off?  Because tearing it off can mess up the thickness and give you an inaccurate reading

[DJK]

7 hours ago, Sniper said:

When you used that plastigauge did you cut a piece off or tear it off?  Because tearing it off can mess up the thickness and give you an inaccurate reading

Sniper, I cut it.

[Sniper]

Well, not cutting it is about the only way to really mess it up, unless it's old and dried out.  I hope the machine shop can sort it out for you and save you the aggravation.

Edited April 12, 2021 by Sniper

[DJK]

It was fresh. I will call the shop tomorrow.

[DJK]

Update: just talked to machine shop, says to go .002 under on rods and mains. Ordered mains from AB, got the last set of rod bearings from Hagen.(closing the doors on the 23rd, so sad!) Fingers crossed.

[DJK]

Update: I am beyond frustrated!! Installed main bearings w/ plastigauge, torgue to 80#, shows .001 clearance, removed crank, installed #6 rod with plastigauge, shows .001 clearance, feeling good. Install crank with prelube on bearings, no rear main seal at this time, torque to 80#, can't turn crank at flywhhel end with a 30" bar!!! Remove crank, install #6 rod with prelube, torgue to 45#, can't spin rod on crank!!! Machine shop had measured to determine I needed .002 under bearings. I am ready to say the heck with it and put the old bearings back in OR send it back to machine shop and say just do what needs to be done. I thought this would be a relaxing enjoyable project that started back in Jan., but it is getting annoying. Sorry for the rant. PS my manual states .0005 - .0015 clearance, could this be wrong?

Edited April 16, 2021 by DJK
update

[Sniper]

Well, I can't say, I don't use plastigauge because I don't trust it.  But I do have the tools to measure it.

 

Here is Mahle's paper on it

 

https://www.mahle-aftermarket.com/media/local-media-north-america/pdfs-&-thumbnails/cl77-1-205r.pdf

[keithb7]

Sorry to hear that. Sounds like you are getting a bit of a run-around.
 

The good news is you got your .002  bearings quickly.  Lots of us would be delayed a month or longer waiting for parts to arrive. Then to find they don’t fit. You wanna talk about frustration?
 

That’s when tools may fly, and the rye starts pouring. Lol. 

Edited April 16, 2021 by keithb7

[DJK]

On 4/16/2021 at 6:32 PM, Sniper said:

Well, I can't say, I don't use plastigauge because I don't trust it.  But I do have the tools to measure it.

 

Here is Mahle's paper on it

 

https://www.mahle-aftermarket.com/media/local-media-north-america/pdfs-&-thumbnails/cl77-1-205r.pdf

Sniper, good info. For the 2.062 rod the manual calls for .0005 - .0015, Mahle says .0025 is acceptable for a 2.00" diameter shaft. At this point, I will go back to std. bearings and be happy with .003 clearance. The mains at 2.5" diameter should be OK with .003 clearance also.

Edited April 18, 2021 by DJK
update

[DJK]

3 hours ago, keithb7 said:

Sorry to hear that. Sounds like you are getting a bit of a run-around.
 

The good news is you got your .002  bearings quickly.  Lots of us would be delayed a month or longer waiting for parts to arrive. Then to find they don’t fit. You wanna talk about frustration?
 

That’s when tools may fly, and the rye starts pouring. Lol. 

I don't know if it is a run around or just not understanding a 69 yo engine. I already sent back the std. bearings, and the .002 rod bearings came from Hagans with no return due to they are closing the doors on the 23 of this month. This has been in the works since mid Jan. and I would like to complete it before summer is over! Good thing I don't drink!!

[keithb7]

I feel your pain. I won’t go into details but I had a goal to have my engine rebuild completed for 2021 summer cruising....I now realize that has evolved into a pipe dream. 

[Dartgame]

I'd buy a dial bore gauge and measure the mains and rods when torqued to spec. and verify your caliper is accurate when measuring the crank journals. .003 is a little on the loose side, you might end up getting some .001 bearings....as it seems that your .002 bearings are too tight.