TheSamba.com :: View topic

Sun Aug 04, 2013 11:26 pm

OK, I F'd up. I bent 3 pushrods while cranking (not running) the engine because I failed to check if the rods were properly seated in the lifters after reinstalling the rocker gear. Just working too fast, forgot how easily they fall out of the pocket. I'll explain why I had pulled the rocker gear in another post, let's just say they're 1.25:1 and I was having some tube clearance concerns.
I happened to have several spare rods, so I replaced the 3 badly bent ones and put in the straight ones. I thought to myself, "you've bent some valves!".
After correctly reinstalling things, I fired it up. It ran like crap, like it was limping on 3 cylinders. This seemed to confirm my theory.
I went in and checked the adjustment on the suspect valves. They all appeared to be OK. A bent valve should have an out of wack adjustment, right?
I fired it up again and it ran fine. I drove it up the meanest hill in town and noticed no issues. My theory is that I had initially compressed a lifter or two during the rod bending incident. It took a little time to pump them up, so that's why she ran like crap at first.
Question is, can you bend rods on a vanagon without bending valves?
No time for a leak down test right now, we're going on a 4 day camping trip tomorrow. Keeping fingers crossed.

Sun Aug 04, 2013 11:30 pm

Yes, you can bend push rods, install straight ones and everything will be okay.
You have solved your problem.
Cheers, Paul.

Mon Aug 05, 2013 7:03 am

I am not there, but I would think the pushrods bent because of some force they were not designed to handle, In other words, the valves may have contacted the pistons and something had to give. If it is running like crap, you may have bent valves. A compression test or better a cylinder leak down will tell you for sure. I suppose if the valve springs got into a bind from being over compressed, that would have bent the rod as well as driving the retainer into the valve guide. Bummer

Mon Aug 05, 2013 8:17 am

Agree with Paul - would not worry about bent valves. If this vehicle has old gas, has sat for a while then suspect crudded valve guides causing the valves to stick and bent pushrods. If so it will happen again on a cold start. The fix is to put marvel mystery oil in the fuel and the oil and spray carb cleaner on the valve stems and work them. An easy way to check is to pull the rockers and tap on the valve stems with a brass hammer or similar soft metal. Cold engine. If the intakes sound different, or they tap in and stick then you have your answer. Spray and tap until the cleaner has rinsed away the ring of grundge then reassemble with the MMO and take for a long drive without shutown such as an hour on the freeway.

What's the history - did it sit?

DougM

Mon Aug 05, 2013 9:53 am

Like I said before , it was my fault. Engine and heads are fairly new. 3 of the PR's were not seated right. This put them at a sharper angle (especially with the ratio rockers) and made them longer than they should be. This wouldn't have effected valve timing, only lift (and possibly their ability to close all the way). Just wondering if the rods could have been bent by forces not related to valves contacting pistons? Anybody else ever made this dumb mistake? :oops:

Mon Aug 05, 2013 10:58 am

I sort of said how in my above post, but to recap, if the springs were bound under load, meaning the coils were touching, then that would bend the pushrod. That would actually be good news. The other possibility would be that when the valve was depressed, the retainer bottomed out on the valve guide, but I bet the spring would bind first.

When you get it sorted, you need to check for coil bind since you've installed ratio rockers. With the valve fully open, you need to be able to get a feeler blade between each of the coils. If not, it won't last. I'd say you need a minimum of .010 clearance between the coils.

Mon Aug 05, 2013 12:01 pm

rsxsr wrote: I sort of said how in my above post, but to recap, if the springs were bound under load, meaning the coils were touching, then that would bend the pushrod. That would actually be good news. The other possibility would be that when the valve was depressed, the retainer bottomed out on the valve guide, but I bet the spring would bind first.

When you get it sorted, you need to check for coil bind since you've installed ratio rockers. With the valve fully open, you need to be able to get a feeler blade between each of the coils. If not, it won't last. I'd say you need a minimum of .010 clearance between the coils.

Thanks. I was thinking along the same lines. Coils aren't binding when properly set up. Leaving for the moutains, I hope the Vanagon Gods are with me.

Fri Aug 09, 2013 6:08 pm

Success! 8 hours of driving on steep mountain roads and we're home safely.
Looks like no valve damage. Must have just bound up the springs and bent the rods without contacting the pistons. No issues now, with strait rods installed.
Thanks for the encouraging words.
Words of wisdom, always triple check that push rods are aligned with lifter buckets when wrenching down the valve gear.

Sat Aug 10, 2013 4:35 am

Easy done not getting pr in lifter center, drivers side as the water pipe in the way of checking them. I bent 1 on 1st eng, 1st wbx.