I have a new 302 crate engine that has some issues that I am trying to figure out, the business that sold it to me is going to replace it but I would like to know what is going on? It is a SBF 302 with nothing to major, just a 268H comp cam and roller tip rockers. It is completely rebuilt with new guide plates and in 120 miles the push rod tubes have worn into the guide plates on pretty much all of them. It popped off a three rockers and this thing burns oil like crazy. It smoked from the passenger side right from start up and would smoke going down the road when you let off the throtle. The guy that built it thought maybe the guide plates were not hardened and thy were to soft an that is why the push rods wore into them. Just looking for opinions. Thanks
Uh yea, that would be why. And that material that is missing from the pushrods? It didnt just "go away", it passed throught the bearings, and has probably scored the crank as well.
Ya, that is what I said to him so instead of sending him the heads he is getting the whole motor and is atarting to build me a new one. The only problem is I will be out of a motor for 3-4 weeks with shipping and everything. It is not the push rods that are wearing, the guide plates are half gone.
Holes in the heads still guiding the pushrods? Holes should be opened up when using guide plates so there's no interference. Wrong rockers (guide plate or guided tip rockers will fight with each other). Geometry problems? See where the tip is riding on the rocker and valve stem. Oil burning is probably bad guides. Bad guides let valves do all kinds of movements. Sure this guy knows what he is doing? SPark
So are the pushrods or the guid plates wearing? If it is the pushrod that is wearing then make him put chrome moly pushrods in your new motor. You must run chrome moly push rods when using guide plates on a small block ford to prevent this exact issue. Stock Ford pushrods are notchrome moly.
Two types of rockers on a 302, either a rail type rocker or non-rail. the rails are to hold the rocker on top of the valve, the non-rail that is used with the little square holes in the head or guideplates. Sounds like you have a mis-match of parts. Take a pic of the rockers and the holes in the head the pushrods go through. Even though you have the correct pushrods and guideplates, something is binding. Smoking when you let off the throttle usually means a bad intake gasket or intake guide.
When I first read it, I thought it was the pushrods that were worn. If you are running rail rockers with guide plates and hardened pushrods, then you would have the guide plate wear described. And the guide plate material has passed through the motor same as the pushrod material would, so I would look at the crank. Take a look at it for yourself, i would think twice about taking this guys word for it.
You said it was a crate engine,did the shop test run the engine before they sent it to you?I would definitely check everything before installing the replacment engine. At least you are getting a replacment.
If I recall the guide plates are there for insurance more than to actually come into constant contact with the pushrod. My guide plates and push rods never came into contact with each other. I was running a large diameter moly custom rod and moly guide plates. A set of Harlan Sharp Roller rockers. Contact upon inspection meant bent rod, which you would inspect because you had signs of a performance drop in the running engine. Your push rods may be bent.
This is all true but the question becomes is it the push rod that is wearing or the guide plate? The guide plate is there for a reason to keep the push rod where it is supposed to be. When you run guide plates you run molly push rods, unless you are running composite guide plates. Manley makes composite guide plates to run with soft (stock) push rods. Your guide plates should not be doing anything more than keeping the poshrod in line, if it is really rubbing hard on the pushrod there is a problem with your valve train geometry. That is cured by using the proper length pushrod as a rule. When you change valve train components you normally have to change push rods to one that is the proper length for the rest of the pieces. Modified engines are not just screwed together, there is a lot of checking and makeing adjustments that goes with the process. A rebuild shop is not the best place to purchase a modified engine. you need to get with someone that knows or learn how to do it yourself and know what to tell the machinist so it will come out the way that you want it to.
Third post in this thread says the guide plate is half gone, push rod fine. That's why I say he has a geometry problem or is mixing parts. My guess is the holes in the heads weren't opened up when the guide plates were added. Usually with guided tip rockers, you damage retainers or the rocker before wearing anything thru. Something is in a bind. I would like to see pics of the rockers and how they sit on the valve stem. Also pics of the original holes in the heads vs guide plate location. SPark
Ive seen a few "well built" SBF's, that had similiar problems. By well built I mean the guy that assembled the engine, that said I made him aware of the Adjustable guide plates that Isky sells. I am NOT saying 100% this is your problem. But you should look at the idea. The engines in question well quite like your build, O/T late model 5.0 Mustangs. The adjustable guide plates cured the issue for my friend and his customers.
I do not want to name the builder yet as he is replacing to motor and has not seen it in person yet. I live in Canada and he is in Arizona. The motor is on its way, if he jerks me around I will tell who it is, he is a reputable shop. I did search that and a friend had a motor from him and it was okay, shit happens i quess.
You can loosen the studs and move the guideplates around until the rocker arms are centered over the valves. Wow, that looks bad! Any bent pushrods or studs?
There are so many valve train issues in those pictures I do not know where to start. I hope you left it as in these pictures so he can see what is going on.
Yes, it was left just as you see it. I hope when he see's the motor and figures out what all is going on he is honest and tells me what they did wrong. It is a major pain in my ass pulling it out and sending it back and now waiting for it to get back there and him to send me another engine. I would like to get some compensation but I doubt he will offer anything.
The Jalopy Journal
