California Engines Pk 80 experiences and questions

[gearhead437]

Dear Fellow Gearheads-After checking my HF inch pound torque wrench and 1/4" socket adapter, I am wondering if anybody has any feedback on assembling a California Engines Pk 80 kit.

Broke two studs on my 49cc Grubbee years ago and it was not fun replacing those. Ending up tossing the torque wrench and using mechanics feel. Lasted until it was stolen.

I realize that the studs have to bottom out, otherwise one can get a false reading. I also know that Loctite or oil can also cause a false torque reading. Does anyone know what size the Acorn nuts are on the California Pk80 engines and if one needs a long metric socket?

Although I was told 12 foot pounds, I was going to start with 8, then 10 and then 11 and then stop until I ran it. Then I was going to let it cool off, check for any loose fasteners, and then tighten to 12 foot pounds (144 inch pounds) if needed.

The Bikeberry 66 cc assembly video recommends "snug" for torque value and perhaps this is to prevent people from overtightening? Heck, I just discovered that most engines are NOT shipped assembled due to liability issues and that one must ensure that the piston ring gaps face the intake port and not the exhaust port, correct?

There are pressed in pins that ensure that the rings are staggered, but if the piston is inserted in the jug incorrectly, regardless of the arrow, the rings can break from hitting the exhaust ports, correct?

I know about the piston arrow needing to point to the exhaust port, but there could be an issue with quality control and the arrow is stamped on the wrong side, not that China products have QA issues Anyway, I appreciate any detailed feedback from anyone that has had to deal with this particular engine kit, okay? TIA-Gearhead437

 

[DAMIEN1307]

I realize that the studs have to bottom out, otherwise one can get a false reading. I also know that Loctite or oil can also cause a false torque reading.

Correct.

Although I was told 12 foot pounds, I was going to start with 8, then 10 and then 11 and then stop until I ran it. Then I was going to let it cool off, check for any loose fasteners, and then tighten to 12 foot pounds (144 inch pounds) if needed.

I see nothing wrong with that proceedure.

one must ensure that the piston ring gaps face the intake port and not the exhaust port, correct?

There are pressed in pins that ensure that the rings are staggered, but if the piston is inserted in the jug incorrectly, regardless of the arrow, the rings can break from hitting the exhaust ports, correct?

Correct on both counts.

I know about the piston arrow needing to point to the exhaust port, but there could be an issue with quality control and the arrow is stamped on the wrong side, not that China products have QA issues

No problem at all...Their 12 year old quality control experts even make sure that everything is made with Genuine Chinesium, no exceptions...lol.

 

[Wrench]

Use an Inch lb torque wrench

 

[gearhead437]

Dear Wrench and Damien-Thanx for the quick and detailed replies! I do have an inch-pound 1/4 " drive torque wrench, the finest that Harbor Fright sells Wrench, do you use specific torque values when tightening head bolts or do you do it by feel? Do you guys recommending blue loctite on the stud bases, letting it fully dry before applying torque? Thanx again-Gearhead437

 

[GW's Motorized]

144 Inch lbs for head bolts

 

[GW's Motorized]

And blue loctite is a good idea for pretty much all of the bolts. It's also recommended to upgrade all hardware

 

[DAMIEN1307]

Dear Wrench and Damien-Thanx for the quick and detailed replies! I do have an inch-pound 1/4 " drive torque wrench, the finest that Harbor Fright sells Wrench, do you use specific torque values when tightening head bolts or do you do it by feel? Do you guys recommending blue loctite on the stud bases, letting it fully dry before applying torque? Thanx again-Gearhead437

And blue loctite is a good idea for pretty much all of the bolts. It's also recommended to upgrade all hardware

The studs and nuts for the cylinder jug and or head is the one thing I NEVER use blue locktite on...it will throw off any accuracy of torque settings.

I also admit that as an old time mechanic, even though I am using the same Harbour Freight torque wrench, I still tend to go more by feel than the actual torque setting...lol...lol.

 

[GW's Motorized]

Oh, I didn't know loctite will throw off torque readings.

 

[Kim AC]

Oh, I didn't know loctite will throw off torque readings.

Think about it - Loctite is like glue, it increases the resistance of the nut/bolt connection. If you've glued something then of course the torque reading will be higher. Don't use loctite - simply set the correct torque setting.

 

[Wrench]

Yep, Loctite will throw the torque value off by 15% but torque values are not an exact science anyways
Since torque value is not the breaking point of the bolt but only 50% - 55% stress value, you can still use loctite
You can make the 15% reduction on the torque wrench before tightening, which can be important with smaller bolts

Torque values are determined for bolts with dry threads
When the threads have (lubrication) oil or loctite on them the torque is increased by 15%