Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[brassspike]

Was just buttoning up after replacing '12 lifters. Set valves and turned over the engine with the rear wheel, plugs out. I had the thing on tdc when I dissembled it but forgot that I had spun the motor while I had the cam chest apart. When I reassembled, I had the timing marks correct, chain direction correct (marked the gears and chain so even the same tooth and link were back together) Anyway, it had a little hitch as I turned the motor.
Can this engine be out of piston timing if the cams are correctly timed? Looks like as long as the crank sprocket is on the flat and the cams were timed correctly, the pistons would be in the proper spots? It's late, I'm tired, and wondering if I just bent valves. Battery was weak so planning to start it tomorrow.

[*58Vette]

As long as the cams are in time and gears were lined up, It's in time.   

[brassspike]

Thanks 58vette! Can't start it anyway because the battery took a dirt nap. Would have thought more have know the answer? The more I thought about it the crank could sprocket could have only gone on one way or 360 degrees (the same) pistons would be in the same position. I guess what I was feeling when turning the wheel was the valvetrain.

[popsracing]

You replaced the lifters and set the valves?? Do you mean set the push rods or did you have the rocker boxes off and do something with the valves???

[brassspike]

Used S&S oil pump, cam plate, lifters, and quickie pushrods @4 turns per S&S. Everything is in time. Just didn't feel smooth when turned with the back wheel. The only thing that I didn't check is tdc when I realigned the crank to the crank sprocket. Worried me that I may have bent the valves turning it over.
Thanks

[popsracing]

When you adjusted the push rods were you sure the cylinder you were working with was on the compression stroke and at top dead center?? This will put the lifters on the non lobe side if the cam which is where they need to be when adjusting the push rods. If you didn't check for TDC for each cyl individually before adjusting the push rods they very well could be and prob are adjusted wrong now.

[timo482]

the description of the problem - sounds at first read - like the push rods are not adjusted properly.

and yes - you CAN bend push rods if they are adjusted improperly - take a look at the rockers.. and verify its done right.

[brassspike]

I agree that the PRs seem to be pretty tight but that's what S&S has for adjustment, 4 turns. I had one cylinder on overlap while setting the other?  Adjusted, waited for leak down before turning engine over. Did it twice to make sure. Seems to have good compression but can't really spin it until I get the new battery.

[brassspike]

When you adjusted the push rods were you sure the cylinder you were working with was on the compression stroke and at top dead center?? This will put the lifters on the non lobe side if the cam which is where they need to be when adjusting the push rods. If you didn't check for TDC for each cyl individually before adjusting the push rods they very well could be and prob are adjusted wrong now.

Not exactly tdc but close. other cylinder was on overlap.

[grc]

I think it might be a good idea to revisit the pushrod adjustments BEFORE cranking it with the new battery.  Turn it by hand and feel any kind of solid interference, and something probably isn't right.  Crank it over with the starter motor and if something isn't right you will definitely damage parts.  Better safe than sorry.

JMHO - Jerry

[Twolanerider]

Also make sure nothing up top is touching the rocker boxes as you rotate. 

[brassspike]

Thanks. I don't have the battery and it's not riding weather so I'm just going to pull everything back out one piece at a time. If the valves are bent and the heads have to come off might as well look into a mild port job and 117 drop on. 

[brassspike]

I think it might be a good idea to revisit the pushrod adjustments BEFORE cranking it with the new battery.  Turn it by hand and feel any kind of solid interference, and something probably isn't right.  Crank it over with the starter motor and if something isn't right you will definitely damage parts.  Better safe than sorry.

JMHO - Jerry

Jerry, it turns over by hand it just doesn't feel right. Has compression too. When I say fell right, I don't know what the feel is supposed to be. First lifter job on one of these but have done v8's. Just finished my BBF stroker and it didn't feel like this one. By the end of the day I should know what's up.
Thanks, for answering up.

[popsracing]

Not exactly tdc but close. other cylinder was on overlap.

Thats right opposite cyl has to be on overlap...After you give the rods your adjusting time to bleed down they should loosen up and you should be able to rotate them...maybe try 3 1/2 turns instead of 4 too.

[brassspike]

Well gents, here is where I am now.
Took the whole thing back to the bones. A soon as I removed the PRs the motor spun free. Checked the timing from the cams on back up and all was correct. I did find that the cam tensioner was worn and had some small pits so I'm going to replace it.
I pulled the rocker covers and everything looks good. I'm going to check for any spring binding once the PRs are all adjusted. Thought I would put in some new oil separator umbrellas while I'm in there.
So, what the heck valve spring pressures do these things run? I can see now why there are lifter failures!! I'm in high gear and I can feel every ramp of the cam, even a little kick back if it rolls off the lobe just right.
Are there different length lifters for twin cam motors? About the only thing that I can think of now is pulling a lifter and measuring against stockers that came out.