76stingracer

Working on getting the motor completed and assembling the roller rockers, rocker studs and pushrod guides. The heads are Dart Pro1 (200cfm). Roller rockers are 1.5. On the intake valve stem the roller rocker sits a little to side. Using the guide plate to try to move the roller rocker in line pushes the middle of the push rod agains the heads. The pattern on the valve stem is centered from the roller but it is a little off center. See pictures in my phote ablum.

Looking up a tthe push rod and head.


I am going to be calling Dart tomorrow morning but was wondering if anyone has seen this before. Thanks for your input.

jackson

can't you rework the pushrod hole thru head with a round hand-file?

forman

is the push rod rubbing on the head or is the rocker just not center. are they all like that or just that one

Indiancreek

What size are your valves? Are the heads so that you'll have to use off set lifters to get the proper valve train geometry? Move the push rod to the outside of one of your lifters and see if everything lines up then. Just for measurement as you can't run them that way for sure.
Putting large valves in requires at times the offset lifter.

7t9l82

offset lifter??? maybe offset rocker.

Indiancreek

There are offset rockers and offset lifters. The pushrod pocket is not centered in the lifter floor in one of the lifters in rollers as they are held in place so the offaet stays on the correct side of the lifter bore.. Generally used in heads with oversized valves.

427Hotrod

Look in the box the heads came in. There is a paper that discusses the issue. The intake valves are moved slightly on the Pro 1 heads.

http://www.dartheads.com/wp-content/...Rock-Align.pdf

They'll end up slightly crooked looking and off center...but get the pattern centered and narrow as possible with proper pushrods and you'll be fine.

JIM

76stingracer

The push rod is touching the head. The more I adjust the roller to be centered on the valve stem the tighter the push rod is against the head. The pictures show the best I can get without the pushrod touching the head.

I read the paper from Dart explaining the offset in the intake valve. Just seeing the roller tip not centered doesn't sit right with me. I could possibly grind a groove in the head to help clearance the push rod. Two issue I see with this is the area that needs ground is the wall to the intake port (somewhat thin to begin with) and second is grinding on $1400 heads to make clearance for push rods. Crazy Dart can not get this right. Calling Dart in a few.

Indiancreek

Don't grind the head. Are you running a roller cam? Have you checked out the offset lifters? If you had the pushrod offset at the lifter end would that help your clearence?
I wouldn't run the engine with the pushrod at an angle as that will force the rocker to empart lateral pressure. Imagine that at 6,000 RPMs.
Take a look at the offset rocker that was mentioned earlier. It may take a combination of both the rocker and lifter being offset. I hope the rocker will get it as they are very proud of offset roller lifters. But yet, look up a Jesel set up, you'll see some real proud folks. Great stuff though. If a guy had a customer with unlimited budget you could build a killer engine.

76stingracer

This is for a hydralic roller cam shaft.

Answer from Dart:
The rocker arms will be at a slight angle off to one side of the valve tip. If you are still having an interference issue at the pushrod clearance hole then their will be two ways to fix the issue.

1.) Measure the material thickness at the pushrod interference and carefully clear some material if adequate to do so. ( Please use caution so you don't break through)

2.) You can run an offset rocker arm to move it over slightly .050" - .150" depending on lifter location.


Will be ordering a set of offset roller rockers. Will update once installed.

gkull

This is my old 383 with Factory ported 215 cc which were actually nearer to 227cc with 2.08/1.625 valves. The pushrods do not hit the heads or scrape the guide plates. They have run for years and some rebuilds.

Notice the angle to the valve stem. Yes, a smart guy would use some kind of offset device, but their okay as is.

MotorHead

That's the aftermarket for you, I am used to it now and if something fits and works like it is supposed to I go out and buy a lotto ticket

Not to make fun but it does say the intake lifter will be on angle. I have run then with just slightly better centering than what you show in you pic.
You can either get a round file and file the hole or get an offset rocker which I had to do both. Not fun when dealing with thousands of dollars invested in the motor, good luck

Here's my intake rocker offset with the correct T&D shaft rockers on the AFR227 heads and a Motown block, I still had to file away some of the material in the block. $2300 for the block and $1200 for the shaft rockers you would think things would fit but they don't. Now my heads are 60/40 valve setup and require quite a bit of offset, yours requires much less

Here's a couple of pics when I building my 427ci notice the intake offset ? You can see pushrods go up straight up

Indiancreek

If you are going to grind on the head the safe way to do it is to sonic test the area you want to grind on.
Some shops have sonic testing equipment, not all. I have one here, but you are in Cleveland and I'm as far away in Ohio I can get, Oxford.
I'll be in Canfield for four days the first weekend in May for the Bob and Ed's swap meet car show. I could bring it with me, as a matter of fact I normally do incase I find a block to buy. But I suspect you want to be finished long before that.

Indiancreek

Hey Motorhead, looks like a stong lift on your engine, what's the lift on that one? Your geometry looks good. Running an angle with a push rods will cause odd part ware.

76stingracer

Indiancreek- Thank you for the offer. I have the offset rockers on the way. Should have them by the weekend. I will try them out and see what things look like.

76stingracer

Update

Offset roller rockers (0.150) arrived today. Without the guide plates installed they are right on the money. Just ordered some Dart adjustable guide plates now that the standard plates do not work.

Now just need to get moving on all the other little projects before I can get this beast in the car.