Help!! Engine won't start??

[racerrad8]

There are a couple of things that can cause the low numbers;

1) Camshaft thrust broke, piece fell down between cam chain & crank causing it to get out of time.

2) Ignition ping burning away the ring lands, head or valves.

I will give you a call tomorrow Gerad.

Randy - RPM

[VMS Motorsports]

Or if he didn't do the compression test with all plugs out and wide open throttle...

[Bigmil]

Yeah, so I need to re-do the compression check.  I did it with wide open throttle but I had the other plugs in while doing it.  I will re-do the compression check when I get home tonight and let ya'll know whats going on.

Thanks,
Gerad

[justfreaky]

I hope your numbers look much better! 
All should be within 5% of eachother

Steve

[Bigmil]

So I re-did the compression with all the spark plugs out and this is what I got
Cyl #1 - 55 psi
Cyl #2 - 28 psi
Cyl #3 - 20 psi
Cyl #4 - 35 psi

Not much better.  I talked with Randy and checked my cam caps (if thats what you call them).  Unfortunatly mine look fine.  No cracks no signs of breakage.  The holes are still there (that are supposed to be).

I did checked the cam timing to TDC and my exhaust side looked odd (he told me to go to TDC and then check the cyl. #4 cam lobes Exhaust and Intake to see if there are parrallel/horizontal to the plane of the valve cover).  It looks like the intake side is correctly horizontal to the valve cover plane but the exhaust side looks obviously off?  Maybe thats my problem?  Even though there are no obvious signs that my cam skipped a tooth or two?

Here are the pics I took showing what I see.
Starting with me making sure it is at TDC and then the intake side #4 cylinder cam lobe location and then the exhaust side #4 cylinder cam lobe location.  Well the upload folder is full?  So I can't upload the pics right now......


Let me know what you think.  I am going to call the engine guy I know to have him take a look at it and find out if I should pull the engine or leave it in the car for him to look at.

 

[JGRacing]

Did you check the valve lash?  Not an engine expert, but I would think that if the cam was a tooth or two off, that the numbers would be bad on all 4 cylinders. 

[justfreaky]

John,

The numbers are bad. They should be up around 160 - 170.

Steve

[JGRacing]

Good point Steve on them all being within the really bad range.  The valve shims would not throw them off that badly.  As bad as they are, they still seem to vary more than I would think.  I was typing before thinking.    

[thunder938]

165 new, this is a 1200 open motor.  Less if the motor has time on it

[Bigmil]

I just dropped the car off at Jerry Knuckles and he is going to take a look at it.  Hopefully I will hear something in a couple of days.

Gerad

[VMS Motorsports]

165 new, this is a 1200 open motor.  Less if the motor has time on it

Thats the rule. 165, but not the potential. I've got a 3 season old motor that I could still get to crank at 185 just by adjusting the cam gears.
Don't bury it 'til it's dead Gerad

[Bigmil]

Ok, so I got the first half of the news (both good and maybe not so good).

He checked my timing and my Exhaust cam was off 2 teeth or so.......he fixed that (the good) and then ran a leakdown test and discovered I was still leaking by quite a bit (the not so good).....
Today he is going to check my valve lash because he thinks my valves may be off to where they are keeping the valves slightly open (I think I read on of the forums that as time goes on your valve lash actually decreases with wear?).  If it isn't one of those he is telling me that I will need to have a complete valve job to fix the problem.
And with over 35 races on the motor (turns out it is a mostly stock bike engine that has never been rebuilt) it would be more appropriate for me to just the whole thing rebuilt.......

Anyway I will let ya'll know what I find out tonight about the valve lash.....I'm keeping my fingers crossed.

Gerad

[thunder938]

If that is a bone stock bike motor and it got 35 races on it...WOW  that is a solid motor to rebuild..

[racerrad8]

He checked my timing and my Exhaust cam was off 2 teeth or so.......he fixed that (the good) and then ran a leakdown test and discovered I was still leaking by quite a bit (the not so good).....

Gerad

Gerad,
         It might have bent the exhaust valves depending on the direction the exhaust cam ended up out of time. If the engine will start & run now it might be worth running it up to temp to make sure there is no debris or build -up on the valve face and/or seat since they might have been in an open position during the ignition cycle and have carbon build up on them.

If it runs, get it warmed up; drive it around a little bit running it through its paces to make sure the valves bang the seats hard enough to clean them.

It might also be a sign of valve build up if the valve lash on the exhaust side is big. The build up will hold the valve away from the cam making the adjustment out of range.

Did he give any indication why the cam changed position?

If you do have to repair the head, as I previously recommended, you should do a complete rebuild.

Randy - RPM

[Bigmil]

Even worse news......
Apparently the reason the exhaust cam was off was because the cam bolts broke thus not allowing the cam to turn properly.  He said the only thing that even remotly kept the cam turning was the friction in the motor.. 
He also believes that I damaged some valves when this happened (and he doesn't recomend driving it like that)......so, there goes engine number two for my first season......
Now I just need to see if I can still borrow one to limp through the final 12-13 races.......

Yeah, I guess the only good news is that the motor is a really good candidate for rebuild......except of course it means I will need to buy new pistons as the ones in their are obviously stock....oh, and I need a pinned cam, which I am not sure is included in a rebuild or not (hopefully)......

We'll see what I can work out, all I know now is that I can't afford to get the whol emotor rebuilt just yet.  But now that I have experienced racing for the first time....I just can't stop and wait for the money to come in.  I need to get back out there.

I'll let you know what I figure out.....

Thanks for all your help!!!
Gerad