Blew a head gasket so I figured it was time to put these aluminum gn1 heads on... I also upgraded the cam to a 204/214 flat tappet... got it all together and fired it up and it's super noisy... had 60 pounds of oil pressure... my question is... do I need a different length of pushrod with using gn1 heads? I used stock rocker arms and shafts... I figured if it was the lifters needing to pump up it would have done it by now... thanks for your help
New combo noisy startup???
- Thread starter sick GN
- Start date
Buick Mark
Active Member
- Joined
- Sep 12, 2001
Did you check lifter preload?
I didn't check anything... I was under the assumption that everything was basically the same... I used the stock rocker arms and the cam I put it I didn't think would have changed the pushrod... now if the aluminum gn1 head does change it then that's my problem... Anyone have a setup of a gn1 head with stock rockers and a flat tappet cam and can tell me what they used for pushrods?
You have to measure. It doesn't matter what anyone else may have used
Its always a good idea to check things when you go to an aftermarket head, I have not used GN1 aluminum heads but have used plenty of other manufactures aluminum heads on various builds and they are usually cast thicker requiring a longer pushrod....I'm sure someone will chime in with an answer for you
ek02
Well-Known Member
- Joined
- Jan 31, 2008
I believe GN1 heads have the valves closer to the center of the cylinder than the stockers, so the pushrod length will be different. Get an adjustable push rod from Full Throttle, set it up so the pre load is correct, and measure it. You can order push rods from Comp or Smith Brothers.
Last edited:
forcefed3.8's
Buckeye Bullet
- Joined
- May 26, 2002
They require a longer pushrod.
It's a good idea to check anything you are bolting on. Who's to say someone hasn't used the wrong pushrods prior. I've seen these come through with pushrods too long, too short, hitting the pushrod holes, running in coil bind, poor rocker alignment, rocker arms hitting valve covers, one chevy I worked on had two different heads with different combustion chambers, wrong springs, two different head gaskets on the same engine, wrong length bolts on rocker shafts, stripped threads all over the place, oil drain back on rear of head blocked, accessory bolt thread through into water jacket, and probably 10 other things I forgot about. All were done by people working on them.
Always check EVERYTHING. Get into the habit of going over EVERYTHING. It's amazing the amount of little stuff you can find just by pawing at new parts while watching TV! 
What scares me is you have a flat tappet cam. (possibly with non hardened tappets) that's been jumping off the nose and smacking down on the cam blank before it's work hardened.
What scares me is you have a flat tappet cam. (possibly with non hardened tappets) that's been jumping off the nose and smacking down on the cam blank before it's work hardened.
I had this same problem when I put my GN1 heads on. It's the pushrods. The GN1 heads require longer pushrods than stock iron heads. DO NOT run it without getting the proper length rods. Mistakes happen, get the right push rods and you are going to love the car! Earl brings up a good point though, hopefully the cam hasn't been damaged. My stock camshaft had 117k miles of hardening when I dropped on the GN1 heads. No damage from the wrong size pushrods thankfully! I hope everything turns out okay for you.
Always check EVERYTHING. Get into the habit of going over EVERYTHING. It's amazing the amount of little stuff you can find just by pawing at new parts while watching TV!
What scares me is you have a flat tappet cam. (possibly with non hardened tappets) that's been jumping off the nose and smacking down on the cam blank before it's work hardened.
I didn't think anything scared Earl... except maybe running out of beer.
Yup and you could build an engine with everything corrected and it won't last anywhere near as long. The two different head engine I worked on lasted a couple years and swallowed hundreds of pounds of nitrous. It's crazy how long some really wrong things last.
BPE2013@hotmail.com
ITSAV6
It's my Granny's car!
- Joined
- Nov 13, 2001
I told him when he bought the lil vega it had galvanived angle iron rear suspension and he didn't believe me lol. I was a lil kid and my Dad had went by his shop lookin for a carb and he was welding it up with a stick welder! It only ran mid 7's in 1/8th with these HUGE slicks. I actually ran his vega at the track one night. I went 7.9 on BFG DR(the year they came out)and he went 7.6 I told my buddys i was gonna get me a 7 and they didn't believe me. I pulled up to his tire store and Doc was there when I pulled up in my Buick and when I got out he shouts. That damn Doug's v6 is almost as fast as "my big wheel car" He killed me on the 60ft lol. He's dead now but we ain't never forgot that! If I knew the vega was going to the scrap yard I woulda took it lol
larrym
West Coast Newfy
- Joined
- Jul 17, 2007
Farmer wrenching that's was my introduction to working on things, me and my grand father would cobble together what ever was broke.
it was amazing how long somethings would last he even tried to "improve" anything new that didn't always work out as planned.
I would love a Vega with a 3.8 be a fun little car.
it was amazing how long somethings would last he even tried to "improve" anything new that didn't always work out as planned.
I would love a Vega with a 3.8 be a fun little car.
