Help on engine build
Turbo Mini Forums

Hi all,

Basically I am re-building my turbo engine, I have put new big end and main bearings in.

Now I am going to torque it all down, by referring to the Haynes manual.

The crankshaft main nuts states 40lb.ft torque
The conrod main nuts states 35lb.ft torque.

Basically I go to torque it all down and once near the actual torque, I just check the crank turns over by hand, it does but very hard. I torque it down to the actual setting and then go to check if the crank turns over by hand. NO JOY AT ALL?

I have put all my brute force in to it to turn by hand, but does not seem to move at all.

What is the problem here, am I going wrong here, have I messed something up?

All help is really appreciated.

Cheers

Bobby

Rod caps on the right way round?

I just asked my old man this, he said yes, but going out to double check this now

Recheck torque settings as you were just asking about them on a different threat. Do you have the correct size bearings in there? We had this once with a bent crank. Torque them up one at a time cheking that the crank still turns between each one...

sounds silly but are the main caps the right ones from that engine?

Undo the rod's and main caps one at a time until it spins, that will tell you where the problem is.

I'd take it back to the start; torque up the mains and check and then go onto the rods; if there is any one particular issue, it should hilight itself pretty quickly - all basically back to front from What Andy has said.

having said that, if there is a risk of binding, I'd check the shells for any damage before going any further

Also make sure you have no crap between the rod/block and the bearings

On each big end, grab each bolt nut with finger and thumb. Wiggle the big end back and forth on the crank. If it moves its fine, if it doesnt, its got the wrong cap or the cap is on back to front. if there is more than one tight, chances are the rod caps are all mixed up.

If all the big ends are free to wiggle, then the problem lies with the main bearing caps. slacken one cap at a time until it frees up, then investigate why. Center cap is the only one that can go on back to front, as the outer two are shaped in a way that is obvious.

Remember, the notch in the bearings all go side by side, not opposite.

Right so I dismantled it all again, and re-fitted it all.
First I done the main caps two on the ends first and checked the crank turns. that is fine.
Then done the main centre main, and that was fine.

Then I went onto the conrods, one at a time. number one was fine, number two slightly harder, number 3 even harder and number 4 and no joy. But when I leave them to the 15lb.ft torque it turns.

are we just talking about ring friction here?

do the test I talk about above^ if all big ends are free, its likely ring friction.

You should really do a 'dry' build with no rings to check that it all spins free, thus eliminating any confusion with ring friction. Then build it again with the rings. Ring friction is the biggest power sap on any engine, and when you have built an engine like I explain, you'll soon realise this.

Edited by Sprocket on 30th Jan, 2013.

Turning all fine now, only when I turn the first go, its a bit hard, then turns over nicely.

Thanks for the advise guys

Bobby

Hahahahaha

On 5th Oct, 2014 Shauna said:
What that's crazy, you go commando hahaha! How heavy is your helmet ?

It did read as though it was a little deliberate, but why not..

No deliberation involved. It was a serious question on a serious subject

This is quite funny, gone from a serious question to jokes