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Old 12-06-2015, 05:28 PM   #1
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Default BP4W Head Condition Inspection

Hey guys, I just picked up this BP4W locally. It seems to be in decent condition. The guy I bought it from was parting out an '00 with a blown bottom end, he did not do much diagnosis on what happened, just that there was "metal sticking out of the oil pan". Obviously that's not great so I'm looking for any signs of oil starvation or contamination. To my (ignorant) eyes it seems OK.

What does everyone else think? What about the carbon on the valves? Normal or signs of abuse? It looks odd. Any thoughts are appreciated.

BP4W - Album on Imgur
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Old 12-06-2015, 07:54 PM   #2
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Under the caps is where damage is most likely to occur.
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Old 12-06-2015, 09:46 PM   #3
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Have a valve grind done and the head boiled out as there is alot of carbon build up or if you have the talent disassemble the head and wire brush clean the valves with a wire wheel on a bench grinder and atleast lap the valves and have the head boiled and then finish cleaning any remaining carbon and either way have it decked. If you are going to do it yourself, check the lifter lash settings and lay the lifters on paper in the order they came out as lapping shouldn't change the settings that much. At the least clean the valve faces and the comb. chambers of the carbon and have it decked.
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Old 12-07-2015, 12:50 AM   #4
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Thanks for the thoughts so far, I'll take the cams out tomorrow and take a look under the caps for damage. I'll likely be lapping & cleaning the valves myself if everything else looks good. I'll have to look over the procedure for the checking valve lash as my shop book doesn't cover it (NA only). The head will definitely be cleaned & decked.
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Old 12-07-2015, 01:04 AM   #5
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Turn the lobe peaks 180 from the lifters and check the gap with a feeler gauge. Should be 8-9 thou on the intake and 12-13 on the exhaust. You can fudge a thou or two on those gaps.
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Old 12-07-2015, 12:13 PM   #6
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Check under the caps. If there was oil starvation or debris, the rearmost intake cam journal will be most likely to have damage IMO.

My personal preference would be to have the head refreshed at a proper machine shop with new high rate valve springs. A head from 15+ years ago is going to have some tired springs in it. Get the job done right the first time. It's a few hundred bucks on top of the parts and it will save you hassle later on.
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Old 12-07-2015, 08:37 PM   #7
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Adding to the good info already mentioned.



You're going to have to deck it, regardless. Get it hot-tanked at the same time, it looks gross in there. This will also remove any possible debris (unlikely). IF you have a good, calibrated, torque wrench, pop off the caps and check out the surfaces. If not, have the machine shop check.


At the end of the day, sending it to a machine shop will result in a higher comfort level, a better product, confirmed specifications, and likely higher compression from the valves. It needs decked, no matter what. Thus, it will be in a machine shop. To me, that means completely check it over, since it's there. Checking it over basically requires tearing everything apart. Thus, if it's apart, do a full valve job when it goes back together. Basically, hand them the head, get a complete valve job, all questions answered.

I paid $400 for a full valve job on my bp6d head. Well worth it, even though it hurt at the time.
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Old 12-07-2015, 08:46 PM   #8
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Quote:
Originally Posted by Onyxyth View Post
Thanks for the thoughts so far, I'll take the cams out tomorrow and take a look under the caps for damage. I'll likely be lapping & cleaning the valves myself if everything else looks good. I'll have to look over the procedure for the checking valve lash as my shop book doesn't cover it (NA only). The head will definitely be cleaned & decked.
Lapping valves is a joke, and whatever improvement you get from it will be gone in 500 miles. If the valves leak at all, lapping won't fix it and hold up, get the valves/seats machined and then they will seal.
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Old 12-07-2015, 09:28 PM   #9
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Thanks everybody - I was definitely planning on getting the head hottanked/boiled & decked as everyone mentioned. I'm on the fence for the valve job just because $$$.

Some good & bad news - I believe the motor this head came from spun a bearing. Check out the album and let me know what you think. From what the PO told me, he shut the motor off as soon as there was a problem and had it towed home. Hopefully that limited any damage. The debris appears to be bearing material from main/rod bearings and as AlwaysBroken guessed the majority of the damage was on the rearmost intake journal. Hot tanking the head should be able to get this debris out, right? or any suggestions on ensuring I get all the debris out?

Most of the other caps/journals look like the first two pics posted, which appears to be pretty normal wear, ya?

The other thing that sticks out is two chips and a casting flaw on the exhaust cam. Thoughts? Is that cam toast? My first thought was just replace the thing but it looks like finding bp4w exhaust cams is pretty hard because people buy them for exintake swaps.

Album:
Cam & Cap Condition - Album on Imgur

Last edited by Onyxyth; 12-07-2015 at 10:44 PM.
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Old 12-07-2015, 09:57 PM   #10
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There's nothing wrong with lapping valves if the seat faces on the valves aren't cupped. When lapping you can tell if they are seating all around. Have lapped alot of valves over the years and had no problems. Valves should be lapped even after a grind to check and make sure they are seating fully as the stones have to be refaced every so often from wear.
The cam lobe looks okay, that normal, probably have some others that have the same look. There are some particles in a few places but nothing that looks like it can't be fixed with a little lite scraping. The few grooves in that cam journal is no big deal, well just hold some oil, the cam is still good if that is the only issues. Just make sure and have the head boiled out good after you take it apart. Get all the carbon out of the combustion chambers before having it decked so as not to mar the deck surface afterwards.
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Old 12-07-2015, 10:06 PM   #11
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No modern machine shop laps valves. If the valves don't seal after the valve seats are cut, then they were cut wrong.
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Old 12-07-2015, 10:25 PM   #12
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That's why you give them a lite lapping, to make sure they are ground right, I know of a couple high end shops that do.
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