Topic: Broken camchain adjuster bolt 400f, case split ???'s

[schwebel]

Well the magical a$$rape has visited me. My 400f engine camchain adjuster bolt snapped. Tried getting it out and it just ain't going to happen. My question is how do I get it out from the inside. Can I just pop off the lower case and access it? Or do I have to dissasemble the entire motor to get to it? Also how big of a job is this? Also anything special I will need to complete this? Thanks.

[ttr400]

Can be a bit tricky to remove with the engine in the frame. This bolt can not be accesed from the inside of the engine.
What I have done in the past, with the engine removed was to get my buddy to spark erode it out. you could also try tig welding on the broken end to get a better grip.

Kevin

[Industrial Rat400f Killer]

Yeah this will be tough with the engine in the frame. I think it can be done though, with patience and time.

1.Try soaking it with penetrating oil before trying any of these.

2.I've had good luck with easy outs but they are brittle and can break so go slow, be careful and buy 3-4 of them.

3. If any if the bolt is sticking out of the case try slotting it with a dremel, hacksaw or file and then use a flat head bit in a ratcheting drill driver, in reverse of course. Push hard and go slow.

The bolt in my spare engine broke off while I was tearing it down for rebuilding. I took the whole engine apart turned it upside down, soaked it with penetrating oil and used an easy out.

[Bill/BentON Racing]

Good advice,but be careful with the easy outs,they can work and they can break,then its time for carbide tipped drills if you had to drill one.Snap On sells a kit of small stud extractors,work real well and rarely break.GOOD LUCK,Bill Benton

[Industrial Rat400f Killer]

Cool, I wasn't aware of those stud extractors, kind of spendy, but better than the alternative if it comes to that.

[schwebel]

Please help with my ignorance, what is spark erroding? I tried the "easy out" method, didnt work. The bolt is not sticking out, but broke where the sizes change of the bolt inside. I am going to remove the engine Sunday, I thought about drilling a hole through most of the center of the bolt and putting another bolt/screw in there to try to have something to unscrew or unbolt. Can I use some kind of "glue" on the bolt/screw? Any suggestions? Worse case scenerio, I also thought about drilling out the bolt and retappingthe hole. But how can I do this without a chunk of the bolt falling into the engine. From that part of the engine does the oil flow straight to the filter, or a screen? I know behind that bolt there isn't much if any oil pressure... where does it go from there. Maybe I can scavange the chunk that falls out? This reallly 

[ttr400]

http://www.sparkeroding.co.uk/

Above link explains it better than I can. I use this method on all broken bolts etc that I can't get out.

As I mentioned before the adjuster bolt does not enter into the motor. Actually it should be called a cam chain tensioner lock bolt, as it locks the tensioner push rod in place. I think the reason this bolt is very often broken off is because it is thought of as a bolt that tensions the cam chain,(and then over tightened) which is incorrect as it's the push bar that puts pressure with the springs on the lower horseshoe adjuster which in turn transfers tension via the slipper to the chain.

The weak part in the system is that the chain becomes slack and then wears grooves in the horseshoe adjuster pivot and seizes. also the springs on the push bar can become weak over time, so when the adjuster lock bolt is loosened the chain does not adjust.

Hope you can understand all that.

Kevin

[schwebel]

 Thanks for the clearer explaination of how that system works, was always a little cloudy on it. I'm going to look for someone to do the spark errosion thing, as that seems like the best option, but unsure if that service is available around here. Would a machine shop have access to this equipment and service ?

 So my question is, if the bolt does not actually go into the motor, will there be a risk in drilling out and retapping. I'm worried about shavings getting into the motor somehow.