I'm learning as I go so please go easy on me. I just Cheked my casting num. On my heads which by the way is a 350 chevy and they came back as 2 different sizes. One head is a 2.02 and the other is a 1.94. how is this going to affect things
if the motor seems to run smooth enough for you, i wouldnt do anything to change it. i've ran motors like that before and in everyday life had no issues. is your motor fuel injected w/oxy sensor in the exhaust system?
It's running very rough . It has roller rockers I've never messed with them by but they keep loosening up on me after a couple miles. Carborated. It has a beefy cam n it sounds good when starting but after it warms up sounds bad and shakes
does it have guide plates for the pushrods? if so, are the pushrods hardened? who built the motor? i love roller cams but they need other things in the motor to help them function. is it a hydraulic or solid roller? so after the motor cools some, things "tighten" back up?
992 and 880 castings are usually 1.94 intake valves and 1.60 exhaust. The difference between these and a set of very expensive 2.02 intakes is so moot as to not matter in the grand scheme of things. I've run 1.94 heads on many motors and they performed just fine. Some cases they were better than the big valve heads due to careful cam choice and gearing. I wouldn't worry about looking for a set of 2.02's. They can be very rare and always expensive. Cockroach Dave P. S. I wouldn't worry about the mismatched valves either unless you are doing some serious engine building or racing. For the street, they're just fine.
What Unkldave is saying is that the engine problems are not caused by the heads, they're caused by the engine build. Find out who built it, how they put it together, what specific parts they used. Find out why the rocker adjustment screws are not lockable (they should have locknuts or set screws to help prevent the adjusters from coming loose). Adjust the rockers according to whether the lifters are solid or hydraulic. Then do basic engine diagnosis. Check, in this order, spark, fuel and compression. Make sure the spark when hot is nicely fat and blue. Verify that vacuum is according to what the cam's specs are; a factory engine would be 18-22" but a bumpier cam will definitely have lower numbers. Verify you have proper fuel pressure, and that it doesn't fall off when the engine's hot. Is the carb an electronically-controlled feedback type? If so, it could be running too lean if the sensors and computer are running because the cam can fool the computer through the MAP sensor. But if the carb isn't a feedback type, it could be misjetted or not working for some reason. Sorry to lay all this on you, but if someone's just thrown an engine together, you can have all kinds of problems to deal with.
I think a cheap set of Poly Locks would solve the problem of tappets loosening. Don't you? They run around $30 bucks.
Depends on which rockers he has. It may just be they were never locked down. 1MM, can you pull a valve cover and snap a clear photo with plenty of light of one of the rocker arms?
Valvetrain issues usually are composed of several possibilities as there are many parts in the system. First you have to find out if it is a solid cam or a hydraulic? Then I need to know what kind of rockers you have. If you have the head serial numbers that would be nice too. Chevy (I'm assuming its a Chevy?) engines are mostly hydraulic cams but if its an aftermarket cam you'll need to find out which it is? The rockers are held on with semi-spherical discs and a pinch style lock nut. This allows for adjustments to the rockers. On hydraulic lifter cam, with the engine off and in the #1 compression position, (Both rockers up!)loosen the rocker stud nuts until you can just barely move the pushrod up and down a bit. Then tighten it up until you can no longer move the pushrod. Then give the nut 3/4 of a turn. Your hydraulic cam lifter is now adjusted. Do this for all the cylinders on each valve lifter rocker and you'll be set. If they re-loosen again, I'd suggest you go to the local speed shop and buy some poly locks. These have an allen head nut inside the rocker nut that is used to lock the nut in place. Ask the guy at the shop on how they work. A photo of whatever system you have on your engine would be of great help so we could diagnose your issues. Good luck, Cockroach Dave
Thank u . My worries r that I'm running two different size heads on same motor . I'm still learning and have 2 many questions
You'll be fine. Or,.. You can always go to the junkyard and find a matching set. $100.00 for a set of 882 castings is not unheard of and they flow well. Have fun doing whatever you decide to do. It's supposed to be fun! Cockroach Dave
It's been too many years since I handled Chebby heads, but IIRC the #882's are a great set; if you wanna update your valve covers, I don't remember the casting numbers, but a set of truck/van "Vortec" heads will give you the newer design valve covers and still bolt up in all other respects.
Thanks for all the responses. I'm working on such a tight budget that I'm forced to park it until I can get some more cash . So I can hardly wait until I can get her back on the road again. My kids are as excited as I am. If anybody has any parts they want to barter I just came across a lot of antiques. Glass wear antique tools and some newer tools as well. Once again I'm learning all this as I go so all the answers r very appreciated.
Yes it has guide plates not sure if the rods are hardened or not. The lifters r hydraulic but I'm not sure who built it. The guy I got it from said the motor has 400 plus hp. I havnt got to find out yet
