The Stovebolt Site Forums The Shop Area Engine Shop No compression 250

I was turning my newly rebuilt 250 over by hand to find tdc (in order to install my distributor) and noticed that I have no compression.
Could it be that I need to do another (better) valve adjustment or could it be something else?

Thanx in advance
Dano

Are the sparkplugs in?

yes the plugs are in, I removed the #1 plug and put my finger covering the #1 spark plug hole and felt nothing as the engine was turned.

Camshaft in time?? Brian

I'm assuming it is since it was rebuilt by a shop, how would I check this out?
Dano

With the valve cover off turn the engine over.
when the timeing marks line up #1 or 6 valves
should overlap. Exhaust will be closeing & intake
opening. I think your valves are probably adjusted
too tight. Are the lifters new? :confused:

Try this - Remove each of the spark plugs and place a small, clean piece of paper towel in each hole. Then turn the crank by hand.

Actually you only need to do this for the #1 cylinder to start. The paper will pop out of the hole at TDC. Before you start, loosen the two pushrods on that cylinder if you've already set them. Now turn the crank by hand and see what happens.

-ftyler

Another easy method is to turn each pushrod by hand as you tighten the rocker arm. Tighten very slow and remove the wrench so as not to put any pressure on the rocker. When it quits turning by hand and you are sure they are just touching, go 1/2 turn down and quit. I find it easyer to set #1 cylinder to #2 then #3 etc.... Watch the rocker arms on the cylinder you going to adjust, and rotate till the intake valve just closes. Then rotate 1/4 more and you should be on the base circle of the camshaft.

Using this method I get to turn the motor after each adjustment so I am always going back and double checking each one I just did. It takes longer this way and you do end up turning it over two times, But I find it easy. Joe

My first guess is that the valves are set too tight. On your #1 cylinder with both lifters down back off the adjusting nut until the rocker arm is barely loose. It should be set about 1/2 turn down from that for initial startup, then tighten them after the engine is running. Better for them to be a little loose than too tight, especially during cam break-in.

I will try to adjust this weekend, thanx to everyone for the suggestions.
Dano

Good call guys!
The rocker bolts were way too tight.

I now have compression, but I still can't get the engine to fire up. Any ideas, suggestions...
Is there a way to set the initial timing without the engine running. I figure if I advance it, it might fire up.
Thanx in advance
Dano

I will try and get this right, its not my idea but have seen it here many times.

First step is to set the #1 piston at top dead center on the compression stroke. Pull the plug and turn engine over till you get compression and the timing marks on the balancer line up with 6* on the pointer.

Step two, set distributor so rotor is lined up with #1 plug terminal on the cap. Check firing order on all other plugs at same time. It doesn't matter which direction its pointing as long as the wires are in the correct order and the rotor is on #1.

Step three, with plug still out of #1 cylinder, ground the plug case to the engine.

Step four, turn on the key to run (DON'T TURN OVER ENGINE).

Step five, turn distributor housing till the plug from #1 fires. Go past this point and come back till it fires again. Now split the difference and lock down the housing.

Step six, turn off key, reinstall plug, and fire up engine.

Step seven, pull vacumn advance and set timing to factory spec's.

Hope this helps, Joe

Thanx Joe H,
I got it to fire up, but my joy hath disappeared.
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Fellow stovebolters I now have two more problems.
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Problem 1: (Maybe not serious)
The starter sounds like its not disengaging once the engine gets going.

I replaced everything on the engine except this. Does it need shimming? Is it a bad starter? Should I just buy a new starter?
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Problem 2: (Serious?)
The harmonic balancer is wobbling like crazy.

"????" This is a new part. Could I have damaged it when I pounded it on? I made sure that I only lightly tapped on the middle hub and not on the outside pulley. How is one supposed to install it without tapping it in. It is not like a V-8, there are no threads on the nose of the crank.
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Any help would be appreciated, I hope I'm not abusing this bulletin board by asking for too much help. I just don't want to have to have it towed to a garage with an unknowledgeable mechanic. I would like to end this topic soon.

Thanx Dano

I had the starter problem on my 250. I tried shims and readjusting till I gave up and bought a new mini starter. Its drilled for both flywheel diameters and is the same as the small block Chevy starter. It cured all my problems plus saved a little weight. You can try the shims, it sure won't hurt. I never could figure out why it wouldn't disengage, I even tried a heavy spring in the solenoid to help pull it back.

As far as the balancer goes, I don't know with out being there. My wobbles some to, so I just bought a new rebuilt one. It came in the mail today. Check yours closer and see if the inner ring wobbles with the outer ring. It could be a bad balancer or as you suggested, knocked out of shape. I believe thats what happened to mine. It seems pretty easy to do, all though, you would think they are stronger then that.

The hot tip is to drill and tap the crank end, but like me, yours is in the truck and not easy to get to. The company I bought from suggested heating the balancer in the over to 240* then cooling the crank end with dry ice or nitrogin. Then if all goes right it might slide on, I hope so anyway.

You can never ask to many questions. Always give as much information as you can for the most accurate responces. Everyone on this board has made mistakes and has needed some help at one time or another. So ask away, Joe hand.

Thanx Joe, I'm going to get a new starter and balancer in the morning.

If I wanted to drill the end of the crank, does anyone out there know the following?

1) What size drill bit and what type?
2) What size tap? (Threads per inch etc.)
3) How deep does the hole need to be?
4) Can I use this for bolting in the balancer?
5) What length of bolt and size of washer is needed? (The small block ones I've seen look too long.)

Thanx
Dano

My memory is fading, but I'm pretty certain I drilled and tapped mine for 7/16-20, same as SBC. I drilled "deep enuf!" and used a Grade 8 bolt and USS washer to retain the balancer.
It works great for installing the damper too, making it possible to R&R the balancer without removing the rad.

http://www.homestead.com/chuckthetruck/Page21.html