7.5 pushrods with 241 heads
Thread Starter
Instructor
Joined: Oct 2011
Posts: 108
Likes: 5
From: coastal ME
7.5 pushrods with 241 heads
Are 7.5 pushrods used on a 241 heads that have been milled? Pulled my 99 coupe apart this weekend and found comp 7.5 pushrods were used. I didn't thing anything of it when I replaced the valve springs earlier this year.
Purchased the car back in late August, and drove back from Texas to Maine. Along the way I broke a valve spring. I was lucky that it wound onto itself and didn't drop. Replaced with comp 918's since that's what they appeared to be.
Had some time this weekend so I pulled heads just to check the rest of the valvetrain out. All else appears good, probably replace the oil pump why it's pulled apart, just looking to get a few more pounds.
It's that time of the year and I'm really getting bored, and want everthing to be just right, when spring finally gets here.
Purchased the car back in late August, and drove back from Texas to Maine. Along the way I broke a valve spring. I was lucky that it wound onto itself and didn't drop. Replaced with comp 918's since that's what they appeared to be.
Had some time this weekend so I pulled heads just to check the rest of the valvetrain out. All else appears good, probably replace the oil pump why it's pulled apart, just looking to get a few more pounds.
It's that time of the year and I'm really getting bored, and want everthing to be just right, when spring finally gets here.
Drifting
Joined: May 2010
Posts: 1,482
Likes: 2
From: Pearland, TX
The stock pushrods for the stock cam and stock lifters are 7.400". Other lengths are available and usually in .025" increments, but I've never seen any build that required a 7.500" pushrod. Additionally, a milled head would need a shorter rod, not longer.
Race Director
Joined: Jan 2007
Posts: 18,643
Likes: 14
From: Norman Oklahoma - The Only State in the Union with no Blue Counties!
We slapped a 228 230 580 581 113 LSA cam in my car a little over a year ago. I should have not reused the stock 7.400 PR's but I did. One bent on a long trip. No damage, got lucky. Texas Speed, full set hard 7.400 running now. Can't see needing 7.500 in your ap. That is a huge increase from what my mentors have taught me.
Still learning!
Still learning!
Last edited by Silverbullet00; Jan 2, 2012 at 11:40 PM.
Thread Starter
Instructor
Joined: Oct 2011
Posts: 108
Likes: 5
From: coastal ME
Thank you for your response to my question. I did some searching prior to my post for the stock length and was some what confused why they installed that length. The cam, intake and heads appear to have been done some time ago by the amount of grime on these components. At the very least this will give me the chance to do a good cleaning. I will try to calculate the lift on the cam and install the proper lenght prior to reinstall of the heads. This is just some of the issues you inherit from buying without knowing the full history of the vehicle. Not a big deal I still like the car, and thingk I got a pretty good deal.
Drifting
Joined: May 2010
Posts: 1,482
Likes: 2
From: Pearland, TX
Thank you for your response to my question. I did some searching prior to my post for the stock length and was some what confused why they installed that length. The cam, intake and heads appear to have been done some time ago by the amount of grime on these components. At the very least this will give me the chance to do a good cleaning. I will try to calculate the lift on the cam and install the proper lenght prior to reinstall of the heads. This is just some of the issues you inherit from buying without knowing the full history of the vehicle. Not a big deal I still like the car, and thingk I got a pretty good deal.
Thread Starter
Instructor
Joined: Oct 2011
Posts: 108
Likes: 5
From: coastal ME
I just got off the phone with an old buddy of mine, and told him what I was up to with the vette. I asked him to stop over this coming weekend and take a look at it. He has done quite a bit of engine building over the years. I try to do most of the work on my things myself, but don't have nearly the experience he does . I'll see what he has to say. From what I can tell from now, the pushrods that were in it should have been matched when the cam was replaced.
thanks again
thanks again
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Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Stock length is 7.385" gauge length. The length you are running sound too long, especially with milled heads. Only other reason I can think of is if they shimmed up the rocker arms, which would require a longer pushrod. The adjustable pushrod is your friend.
Thread Starter
Instructor
Joined: Oct 2011
Posts: 108
Likes: 5
From: coastal ME
Now that I have the heads off I'm rethinking what some options may be. I still have plenty of time to get things back together prior nice weather.
Thanks for the replies to my post. I give an update when I finally decide.
Thanks for the replies to my post. I give an update when I finally decide.
Instructor
Joined: Dec 2011
Posts: 188
Likes: 0
From: Fredonia Wisconsin
The lift of a cam is determined by the lobe height minus the base circle
If the OP is tearing into this thing enough to change out the oil pump
(rack out, balancer off, etc.) he should just pull the cam and find out
what it is. You never know it could be an Ebay regrind and needed the
excessively long pushrods to get quiet lifter preload. Sounds like he has
a winter long project of investigating
If the OP is tearing into this thing enough to change out the oil pump
(rack out, balancer off, etc.) he should just pull the cam and find out
what it is. You never know it could be an Ebay regrind and needed the
excessively long pushrods to get quiet lifter preload. Sounds like he has
a winter long project of investigating
Former Vendor
Joined: Apr 2006
Posts: 2,470
Likes: 2
From: Portland OR
St. Jude Donor '10-'11-'12
Yep, He will be pulling the cam I would imagine.. Need to know what you have before you start making mods to it.. use a pushrod length checker.. I see so many shops and people just guess... HKE always measures even if he's done the combo a hundred times over
Thread Starter
Instructor
Joined: Oct 2011
Posts: 108
Likes: 5
From: coastal ME
I would like to say that I never do anything just enough to get by. What ever it takes to correct something not done right, will be corrected. Probably the average person would have left everything untouched since it was running fine, but that's not me. If pulling the cam is required then so be it. You are correct many people guess at things that's why for the most part I do things myself, paying someone doesn't mean it's done correct. Buying something used you never truly know what your getting.
I had another chance to talk to my buddy earlier today and he's going to come over Sat to check things out. I have no doubts in his knowledge and abilities.
I had another chance to talk to my buddy earlier today and he's going to come over Sat to check things out. I have no doubts in his knowledge and abilities.
