Web-Cam i107 in stock rebuild

[jackstar]

Need some guidance or cyanide, you choose.

Had to do a complete rebuild due to a dropped #3 intake. Only thing original are the cases and crank. New P&C's, rings, Heads by Hoffman, cleaned up stock dizzy from Randy in Maine, new bearings main and camshaft, plugged the oil galleys, new vac rubber, web-cam i107 camshaft with hydraulic lifters, new oil, filter, plugs, haircut, shoes, well, you get the idea. Valves are 3/4 of a turn in from 0 lash, plugs at .028. With that setup I get about 10-12 inches of vacuum. Want more ie. boost assist brakes.

Problem. On the engine stand, I am getting about 8-10 degrees advanced timing with all the vacuum lines plugged. In other words,I am running mechanical advance only. With the vacuum lines connected, I have to back the idle screw out to the o-ring to get any semblence of timing and then it is not that good. Around 5 degrees advanced. Dizzy advances to about 40 degrees all out and upon release stumbles around trying to find idle.

I have had the engine smoke tested (whatever the hell that means) and I am told there are no vac leaks. So, where does that leave me other than scratching my ass and thinking about getting another bottle of single malt scotch? I am thinking of putting it in the bus and connecting everything up and seeing what the hell happens then. Any suggestions out there are much appreciated and welcome. I would even settle for the occasional raspberry and I told you so. Thanks in advance.

Jack

[Bleyseng]

engine needs to be broke in as the rings haven't set yet I'd guess. I can't remember if the i107 is the same as the stock grind.

[RSorak 71Westy]

Yes 1st thing you needed to do was break in the cam. If you didn't, dont even bother putting it in the bus, as the cam is probably failing all ready. To break in the cam, the engine must be run between 2 and 3000 RPM for 20 minutes.

Did you do this?

It must be done the 1st time the engine starts.

Your timing probably cant be retarded enough with the distributor because it's off a tooth. Is the dist. hitting something to limit it's movement?

[Amskeptic]

I am getting about 8-10 degrees advanced timing with all the vacuum lines plugged. In other words,I am running mechanical advance only.

With the vacuum lines connected, I have to back the idle screw out to the o-ring to get any semblence of timing and then it is not that good. Around 5 degrees advanced.
Thanks in advance.

Jack

I am almost totally confused here.
Plural vacuum lines? Like, two vacuum hoses to distributor?

Adjust timing to 28* BTDC at 3,400 rpm. Period.
Now try to fix the other issues.
If you do have two vacuum hoses to distributor, one is a retard. You should then have 5* AFTERTDC, at idle. But, if you can't get a decent 9-950rpm idle without the idle speed screw just about falling out, disconnect and plug the retard hose to the distributor vacuum unit. Then you will live with about 4-7.5*BTDC idle timing.
Occasionally, you will have an incorrect throttle body with a dual advance distributor, and the retard will kill your idle.

As mentioned, a new engine will have a lot of internal friction that may torment your best efforts. It will get better as the rings break in and the bearings lose that new break-in friction. Also, I do not know if your cam has the "better power" grind that torpedoes your low end torque/vacuum signal.

Still confused however.
Colin

[Gypsie]

whatever happened?....

Jackstar, are you there?

C'mon back. Tell us what you found.

Hope it wasn't a 'ground cam'.

[jackstar]

Gypsie,

With nearly 3000 miles on the new engine I am very happy with her and the vacuum. I thought it was going to be a problem with the brakes but once installed and running they work fine.

I am now chasing the elusive high CHT's with stock CA setup lean machine. This past weekend I disconnected the 02 sensor and ran the LM-1 with results in the 15.6 to 16.7 range. Way lean when it should be richer.

Reconnected the 02 and it dropped to 14.7 or so. At least that is working. So, I will get my buddy to read the LM-1 after disconnecting the 02 again and adjust her AFM to about 13.1 to 13.5 and see where my head temps are then.

Film at 11.

Jack

[ruckman101]

How many inches over from TDC on the pulley is 28 degrees? I need to mark Gretchen's. The pulley only had a notch for TDC.


neal

[ruckman101]

One and three quarters of an inch. That was easy. The pulley on Bertha Bus's old engine had a 28 degree notch.


neal

[hambone]

A protractor will work too. I even have one with an "hour hand" if you ever need it. It comes in handy.