FX Nytro engine wont turn over

[Svante]

Hi. I promised my friend to make a post here on a strange problem he stumbled on building turbo on his Nytro -08. This is what happened so far. He set the engine to TDC and removed the camshafts and head. Installed the headshim and ARP bolts and the camshafts, after aligning the marks and installing the chain tensioner he tried to turn the engine over but the crank would only turn for about 3-4deg and then it stops ( doest´nt matter CW or CCW ). Luckily he turned it carefully by hand. When he did´nt find anything else he thought a valve was touching the piston so he removed the camshafts again but still nothing. When i visited him a couple of days ago he was removing the head ( again ) to make sure nothing had fallen down and ended up between the piston and combustion chamber. But everything looked allright. After turning the crank back and forth a couple of times ( by hand ) it suddenly began turning over with no problems what so ever. He bought a new head gasket and installed everything today again. And the problem is back. So i promised i would make a post here and hopefully find a solution.

I helped him to remove the flywheel today just to make sure that nothing ended up down by the crank sprocket but everything seemed to be in order. What can cause this? It does´nt make sense. Being a 4-stroke with the camshafts and sparkplugs removed the crankshaft would turn easily.

He torqued the ARP´s to 42ft/lb.

If anyone has anything to add.. Please do

/Svante.

 

[Tarzan]

Maybe one Arp bolt is touching something?
it is one bolt that you do not have to turn down too far,then its touching something that i dont remember right now.

 

[Svante]

even then there´s nothing above it? The cams are not installed for the moment.

/Svante.

 

[Tarzan]

even then there´s nothing above it? The cams are not installed for the moment.

/Svante.

No down in the engine it can touch something

 

[Tarzan]

It is in one of the side bolts. it is either bolt No. 1 eller2 or 7 or 8 if i remember right.
I dont remember the name of that thing the bolt can touch. But if that bolt is is screwed down too far you wont turn the engine.

 

[Svante]

Ok.. Some of the bolts on the sides then? Maybe we can try release one by one and see wich one that causes it.

If you come up with wich one exacly it is let me know.

And thank you.

/Svante.

 

[Srxspec]

Primary clutch side of the engine and on the intake side of the motor you can only install that stud so far or it will make contact with the water pump impellar and damage the impellar and cause the engine to be unable to turn over.

 

[Srxspec]

Also installed ARP head studs. Be careful on the pto top side stud, if you install it too far it can hit and damage the water pump impeller! I measured the depth with a calipers and then measured the length of the stud and subtracted the depth from it. Thanks to Hurrican Dave for telling me to watch out for that head stud! I then used a calipers to set how far it screwed in as well. I installed the head studs with red loctite on the threads into the block and then just slightly snugged them with an allen wrench. Note both studs on the pto side will stick out further than the rest of the studs.

 

[kinger]

I remember on the apex something about having to cut the ARP studs, looks like a similar issue on nytro.

Great help Ulmer!!

 

[Tarzan]

First remove the original bolts. Clean the threads in the block as well as you can. Check the length of the bolts, adjust the length if ARPene is too long. Grease red Loctite on the threads to be down in the block (remember to install it the right way, it is possible to make mistakes). Tighten the bolts to no more than 20Nm. Let bolts stand for 1 day in a temperate room. Lubricate all threads (not those who go down into the block) with moly grease, grease all slices and surfaces before you tighten the nuts that hold the top down. Tighten to 20Nm first , continue to tighten the nuts in the correct sequence first to 20Nm, then 35Nm, 50Nm, and then finally to 60Nm. When you are at 60Nm then slows to each (one at a time) nut in sequential quarter 1 / 4 turn before you tighten it to 60Nm again, this makes you a nut at a time. You will see that the nut goes a long way past where it was before you slacked up 1 / 4 turn. This is very important as it is this last tension to ensure that the tension in the ARP bolts are high enouf. It is the tension that the bolts are exposed to that hold the top in place. I do not cut the bolts, I added an extra slice of ARP. Nuts may originate from the top of the bolt if the bolts are too long .....
And run the engine warm and then you retork them again.

 

[Tarzan]

What did you found out?
Have you solved the problem?

 

[rxrider]

Svante - how did it turn out?

BTW - welcome to the site, please add your location to your user profile, it's a site requirement.

Hope you will find the problem and fix it.

 

[Tarzan]

Fixed?