| FAQ |
| Members List |
| Social Groups |
| Calendar |
| Search |
| Today's Posts |
|
#1
06-03-2024, 01:16 PM
|
|||
|
|||
Cracks in lifter valley area? Opinions
Hi
Was putting together my 433 with a set of 47 ported heads. Engine is a 9.7CR, 1969 400 block, with Icon forged pistons and stump puller cam. I have run this motor for over 3 years, no issues runs great, about 3000 miles. While putting on the valley cover noticed these cracks or indentations. Hard to tell exactly. I do have a picture from the machine shop of the block and looks like those marks are there initially. Should I try to fix or run it? I think if the cracks were bad the machinist would have said something about it. From my close look it appears they do not go all the way through the block, but hard to tell. Thoughts? |
|
#2
06-03-2024, 01:28 PM
|
||||
|
||||
|
It's hard to tell from the pictures. The ones in the back of the valley near the distributor are a non-issue. The one between the lifters and the head looks like a freeze crack. If it is a crack it should've shown with a Magnuflux test.
|
| The Following User Says Thank You to PAUL K For This Useful Post: | ||
|
#3
06-03-2024, 01:29 PM
|
||||
|
||||
|
Casting flaw.
I’ve seen several block that were missing material in that exact spot at the back near the distributor due to an incomplete pour at the foundry. The ones above the lifter bores don’t look like cracks, just the way it was cast. Your machinist did check the block for cracks after cleaning and before machining, correct ? If so then run it, there’s nothing wrong with your block.
__________________
1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/3.08 2002 WS6 Convertible LS1/4L60E/3.23 1966 VW Type 2 Single Cab Pickup 140hp 2276 1956 VW Type 2 Panel Van 36hp 1200 1957 VW Type 1 Beetle 180hp 2276 |
| The Following 2 Users Say Thank You to b-man For This Useful Post: | ||
|
#4
06-03-2024, 02:42 PM
|
||||
|
||||
|
Most blocks are really thin in the back area or do not have material there at all. I'll take the die grinder and remove the thin flashing just so I don't have to worry about it flaking off later.
Nice fat lifter bores and well centered - looks like no core shift at all.
__________________
Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 Catalina Safari Wagon. |
| The Following User Says Thank You to lust4speed For This Useful Post: | ||
|
#5
06-03-2024, 03:00 PM
|
||||
|
||||
|
Looks a lot better than this one!
|
|
#6
06-03-2024, 03:48 PM
|
|||
|
|||
|
Paul- The one between the lifters and head is not a freeze crack, it’s a shadow from the pushrods. I was concerned about the back wall near the distributor.
|
| The Following User Says Thank You to soupman For This Useful Post: | ||
|
#7
06-03-2024, 04:25 PM
|
||||
|
||||
|
one time long ago i had some funky soft cam bearings had to pry the cam out,.... levered a big screwdriver in that back area against a cam lobe to push the cam foreward and out to replace the cam bearings and i broke a big thin chip out of that area freaked out at first then realized how thin and useless that particular area is and moved on without a broblem
__________________
........... The More You Follow The Herd The Less You Can Be In The Lead .......... |
|
#8
06-03-2024, 05:06 PM
|
||||
|
||||
|
Here's an early production 1970 block. The bottom piece was thick and not going anywhere so I left it in place.
__________________
Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 Catalina Safari Wagon. |
| The Following User Says Thank You to lust4speed For This Useful Post: | ||
|
#9
06-03-2024, 06:19 PM
|
||||
|
||||
|
I would rather have a hole there like in post #5! as I have had in many blocks then a casting flaw like that.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
|
#10
06-03-2024, 07:13 PM
|
||||
|
||||
|
I’ve seen some really horrible lifter bore areas over the years, but never were they an issue.
__________________
LIFT HEAVY, LIFE IS TOO SHORT TO BE SMALL! |
| The Following User Says Thank You to BILL BOWMAN1 For This Useful Post: | ||
| Reply |
|
|
The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.
Linear Mode
