Greetings,
I have questions about 292 Y Blocks and would appreciate any inputs on the following:

Our 1964 292 was hauling 20,000 pounds up mountains very well. The engine only had 20,000 miles on it and used virtiually no oil at all. We began losing power and found that the compression was low on 2 cylinders. Valve adjustment solved the compression issue but the engine is still not as strong as it had been. It also began to use a little oil.

Several events occurred which might be significant:
1. The mechanical advance in the distributor came apart and while troubleshooting we had some serious backfires. We installed a new distributor but the engine was not as strong after this.
2. About a week later while carrying a full load the engine was downshifted prematurely and over revved. It made a wicked sound for a few seconds but seemed to run the same as before this occurence.
3. We noticed that a small amount of radiator fluid had been leaking from the head gasket and running down the block. We tourqed the head bolts and several were found to be not tight, about half of specified tourque.

It has been suggested that burning unleaded fuel has resulted in valve seat problems. We are planning to get a set of heads rebuilt with hardened seats. I was told that 1 piece valves are preferred over 2 piece valves when burning unleaded? Are there any other critical details which we need to know?

The heads we are going to have rebuilt are from a 1958 292 engine. Is there any reason we should not use the 1958 heads on our 1964 engine?

We need all we can get from the engine. We put a 4Barrel Edlebrock carburator on it and it has been converted to dual exhaust. A solid state ignition unit replaces the points assembly. Other than that it is stock. Any thoughts on maximizing performance?

Any inputs you might have would be greatly appreciated.

Palamino73
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torquing the head.s may have started the oil burning.as a rule you dont need hard seats.however as you are working the truck hard it may be a good idea.the 58 heads are good.

 

I agree with 312 that with your heavy use of the 292 hardened seats would be a good idea, though in most normally used Y's they arent required. However it seems like the oil usage would be related to something other than retorqueing of the heads. How much oil is it using?
What heads are you getting ready to rebuild (casting numbers)? If they are 113's their 1.92 intake valve is much larger than the 1.64 currently. Also larger intake runners, which would better matchup with the "B" 4V intake (if that is what is installed). So said they could benefit if your running high rpms. If your rpms are normally below 4000, then C heads might be better, in that their smaller intake valve, 1.78 vs your 1.64 presently, would be more beneficial to torque.
Since your trying to get some more power and are going to have the heads worked on, might as well cut them down for a little more compression. The 113s have a combustion chamber of 72cc. Surfacing them .024 would make them approx. 68cc, and still allow proper alignment of the intake. If the deck surface is in good shape, use steel head gaskets rather than composition type for a little more gain in CR.
Check the valve tips and look for the wear point where the rocker is in cantact to see if it is centered, establishing correct geometry. I cant keep it straight in my head as to whether or not the 113s and the 64 heads use the same length pushrod (there are two).
Those are my thoughts. Hopefully others will weigh in as well.

 

Once other thing crossed my mind on the power loss. Given the motor had 20,000 mi., perhaps the overrev situation accelerated the timing chain stretch, therefore retarding the cam timing?

 

I wonder if your cam is going flat. What kind of oil are you using?

 

The heads have been changed. It appears that there was leakage between 2 cylinders and that radiator fluid had been leaking in several places. The bummer is that we did not fully recover the engine power.

As 46yblock suggested I am now suspicious that the timing chain was altered in the over-rev situation. The truck is in use now but I will have a chance to check/change the timing chain this weekend. Are replacement parts from a dealor such as NAPA adequate? Is it correct that the gears and chain should all be replaced? Any tricks that I might need to know?

Also, when running the engine without the valve covers on I noticed that the oil flow along the trough in the left head was 3-4 times more than the oil flow in the right head. Is this normal? If not, what could cause this? The right rocker assembly and push rods are all being lubricated but the side to side difference bothers me.

If the timing chain is not loose I am not sure where to go from there?

Any thoughts much appreciated!!

 

Depending on the chassis size of the truck (B/F600) there was a 272HD that featured steel crank/rods and had sodium filled exhaust valves. I don't know if you lucked across one of these but regardless of type, the engine should have hardened exhaust valve seats installed if it is worked this hard.

Was the origional 2V carb/dist governed?

As for the oil feed problem, the Y-BLOCK had a unique oil gallery whereas the valvetrain was fed through an opening in the cam bearings. Either this passageway becomes clogged with crud or the bearing spins somewhat cutting off the oil flow. The rocker arms/shafts will quickly become galled requiring replacement.

 

KULTULZ: The truck is an F600. The original carb. was not governed. The casting #'s indicated it is a 292. I am concerned about the oil problem and not sure how to proceed. I am not a master mechanic, but can do the work. My small tree care business can not afford to ruin this engine as I am barely surviving as it is. We carry about 20,000 lbs. when the water tank is full. I was very impressed with the 292's ability to move this load prior to the series of events described previously in this thread.

Appreciate your inputs greatly!!

 

I'm sorry. The 272HD was dropped prior to 64. You had the choice of a 292 M/D or H/D for that year.

If you have any tech material (shop manual), the Y-BLOCK feeds the valvetrain from the mains to the cam bearings and along one galley (each bank) to the bottom of the rocker stand where it is then distributed down the rocker tubes to individual arms. You have to ascertain these passages are clear and supplying oil. Because of the size, they plug up easily. The cam bearing which the valvetrain is fed through has a tendency to spin also causing shutoff of the oil supply.

You would actually have to pull the cam to verify proper alignment (bearing feed orifice). Crud also gathers behind the oil filter galley. It must be removed and cleaned also.

Years ago, you used to see an external feed kit from the pump to each rocker cover. This bypassed the stoppage.

Make sure the road draft/PCV system is fully functional to prevent engine crud.

Don't forget this engine uses solid lifters. After the timing set change, make sure the tappet clearances are correct and that the rockers are not galling on the tubes. If they are (damaged beyond repair) you can buy rebuilt assemblies fairly reasonably. But you have to make sure they are getting oil.

 

The later Y-blocks used a different cam bearing with a groove instead of a hole which solved part of the oil starvation to the rockers. That is what I put in the 1964 292 I rebuilt. They can still have the oil passages get blocked with gunk. Check the oil passage from the top of the cylinders down to the cam while the heads are off to make sure they are clear. When the heads come back, blow out the oil passages to the rockers. When you change the oil, use a good quality synthetic or synthetic blend to prevent gunk building up.

 

Thanks for the info.!!