429 compression results
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Tuned
Joined: Apr 2001
Posts: 443
Likes: 1
From: Athens, AL
429 compression results
i am burning a quart every hundred miles in my 429, so i did a vacuum and compression check....the vac reads at 19" and steady...the compression check low was 125, high 150, indicating ,i presume, good rings and valve guides...what gives??????????
Mountain Pass
Joined: Jan 2001
Posts: 229
Likes: 0
429 compression results
Your high compression means the rings and valve-to-head seals are good, meaning your VALVES arent leaking. the guides may very well be the cause..
Pull your plugs, and look at them. there's pretty much only 3 ways oil can get into the cylinder:
1.Bad rings (you'd have low compression)
2.A bad seal around the intake ports (you'd have low vacuum)
2.Loose valve guides.. You wont get a low vacuum reading off valve guides, because the oil is taking up the space and being sucked into the cylinder..
May very well be guides...How many miles on the engine?
J/.c
1965 Ford Galaxie 500 (okay, so not quite a truck)
460/C6 transplant @ 389hp/491 lb.ft.
14.29@103.8, 13-14 mpg heheheheheh
Pull your plugs, and look at them. there's pretty much only 3 ways oil can get into the cylinder:
1.Bad rings (you'd have low compression)
2.A bad seal around the intake ports (you'd have low vacuum)
2.Loose valve guides.. You wont get a low vacuum reading off valve guides, because the oil is taking up the space and being sucked into the cylinder..
May very well be guides...How many miles on the engine?
J/.c
1965 Ford Galaxie 500 (okay, so not quite a truck)
460/C6 transplant @ 389hp/491 lb.ft.
14.29@103.8, 13-14 mpg heheheheheh
Elder User
Joined: Jan 2000
Posts: 966
Likes: 2
From: Crooked River Ranch, OR
429 compression results
mileage unknown....on another post, something was mentioned about seals....could it be old and hardened valve stem seals??
Yes it could be hardened/broke/missing valve stem seals. They can be replaced without pulling the heads with the right equipment. A defective PCV valve can cause oil consumption also.
Deen Hylton
Ford F250 460 C-6, K&N, Headers, Dual Exh.,Comp. Cams,Shift Kit
Pioneer CD w/Bose Speakers.
Other Passion: Blown 77 Corvette (Sorry Guys/Gals)
How I can afford to Drive the above: 93 GEO Metro
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