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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Your push rods should be about 7.800", with perhaps some adjustment to their length to perfect the rocker geometry. Those look like they're at least .400" too long.
Besides the geometry malfunction, those nuts aren't on the studs far enough for their "lock" function to work. That's just going to fall apart.
I see that those are 187 heads; 305 TBI swirl-port crap. Is this the 88 car/motor in your profile? Do you still have roller lifters in the motor? Is that cam the 280 "Magnum"? If so, that's The Real Problem; roller lifters on a flat-tappet cam.
The motor is a Hydralic Roller motor. It isnt the stock motor for my car tho, but is a LB9.
Parts are from Summit:
COMP Cams Computer-Controlled Camshafts 08-302-8 Hydraulic Roller Tappet, Advertised Duration 264/274, Lift .480/.480 112 LSA
COMP Cams Magnum Rocker Arm and High Energy Pushrod Kits RP1412-16 Roller Tip, Steel, 1.52 Ratio, Fits 3/8 in. Stud, Chevy, Small Block, Kit Included Pushrods
I was afraid of this. I knew it didnt look right. Im bummin, but id rather find all the wrongs now. Thanks. .... It is the car in my profile. Engine from a 89 Formula
Yup, that kit includes the push rods for flat-tappet cams, which are around .500" (½") longer than the ones for roller cams. Totally the wrong part. No adjustment in the world will cure that.
You need a set of push rods. They will turn out to be somewhere more or less within or close to the 7.200" - 7.300" neighborhood. Stock length will probably work fine but if it was me I'd check. I'd suggest getting an adjustable push rod and some checking springs to determine the correct length, then get them here. http://www.texas-speed.com/c-3257-pushrods.aspx
Those retainers and springs also don't appear to fit together right. What are they? (part #s, please) What installed height are they set to, both on the int and the exh?
Yup, that too. Although it does look like those are "early" 187s, with the slot push rod hole; might be OK with that.
That whole setup is in need of a serious review. Crap heads, questionable rocker alignment method, wrong push rods, spring/retainer weirdness, ... needs further effort.
Good eye sofa (retainers) and Drew (non-SA rockers). But from the pic, I think I can make out a double D slotted push rod hole. Yes, push rods way too long. And yes, the rocker stud must protrude through the crimped top of the nut to maintain it's adjustment.
You did the right thing by stopping and asking questions!
I'm glad he asked too...I'm learning a lot. There are so many combinations of parts. But yes, those nuts did not look right, and I'm glad you followed your instincts and asked first. I would not have noticed anything else at a glance.
Also glad we have so many knowledgeable, and helpful members here!
General rule of thumb, centerbolt valvecover heads came with self aligning rockers. Now sometimes the pushrod holes are narrow like older heads, but still the rockers are self aligning. So you should use self aligning rockers or have the heads machined for guideplates.
They're available, but in most cases I'd expect it makes more sense to have the heads machined for guideplates, because most of the time, people will be wanting to run a bigger cam, requiring screw in studs, or have the bosses/seats cut for different springs and seals to accommodate more lift and matching springs.
As much as it's basic hotrodder stuff, it's the kind of thing that makes ready to run heads with all the right features, more attractive. Personally, I've been into the valve train a couple of times with all kinds of shiny new parts to install, only to figure out that something someone online said would work, wouldn't really work. LOL You start messing with 1.6 rockers and the pushrod holes are two narrow. You go to roller rockers, and the stock valve spring retainers can contact the rocker body. You ditch the rotators and oil shields on the stock valve springs, and the spring seat depth is uneven and they require shims or machine work, then the shims require offset locks to get the installed height correct, and the rockers rub the low profile retainers. You get the idea. It's a matched package, and if you mess with any of it, other items generally need to be changed.
Thanks guys. And I agree to an extent Drew. The parts may "bolt on", but there's a lot to understand and get right.
Jegs has those Comp 1417s, and the details do say they are self aligning. But seeing the feature on the factory rocker that MAKES it self aligning (at least as I understand it), and looking at these, I sure can't see what MAKES them self-aligning.
There are those magic little guides. Thanks NoEmissions84TA. I mean, I'm no master engine builder, but I know a little (thought I was starting to question even that).
BTW 88ASC305T5GTA, you guide your rockers with only 1 method at a time.
More than 1 method will fight each other and cause broken parts.
Method 1 - stock double D push-rod slots in the head.
Method 2 - drill those holes open and machine for guide plates.
Method 3 - self-aligning rocker arms. And you cannot use SA rockers with solid flat tappet camshafts.
Not 100% sure about solid roller cams, but I would assume NO also.
I know of no reason you "can't" use SA rockers w solid cams, either flat or roller, other than handling the issue of adjusting them. Which if you have a narrow enough feeler gauge to fit between the "rails" on the rockers, i.e. about 5/16" or narrower (valve stem is 11/32"), isn't a problem.
Factory SA rockers have a wide enough space between the rails that leaves enough slop to where they'll generally tolerate a 2nd locating method such as slotted heads... lots of earlier motors with them, if not all, came that way. Aftermarket ones usually fit to the valve stem more tightly and will not.
My recommendation to the OP would be: get rid of the 187 (TBI swirl-port) heads, and get a pair of 081 (carb & TPI) to replace them; have their push rod holes enlarged both side to side to give clearance to alternate rocker locating methods, and toward the stud to give clearance for the push rod being moved closer to the stud to create the 1.6 ratio, just in case that's ever an issue (after all, if you're having work done, might as well make it as universal as possible, do it once completely and it's done forever); then EITHER buy SA full-roller rockers instead of the roller-tip, OR also have the heads machined for studs & guide plates and install that system. And of course put in the right length push rods.
05-06-2018, 04:21 AM
You get the idea. It's a matched package, and if you mess with any of it, other items generally need to be changed. 