Afaraj

I bought a freshly machined BP4W head a while back and have come to the point where I need to use it. Everything looks great except when I was checking the seal on the valves ( using the car passion/Jafro mobile contraption with the vacuum pump) I noticed that two of my cam caps were not marked with the correct letter and number. Intake caps 2 and 4 are marked with E3 and E5. All other caps are marked correctly.

I placed the caps on without the camshaft ( didn’t torque) and felt around. comparing them to other caps, I could feel a slightly higher ridge on the ones with incorrect numbering. (could also just be my imagination) I fear the person who previously machined/ built the head just threw some random caps on.

I don’t think it’s been run since the machining and I don’t see any issues with the cam journals.

I plan one using a dial bore gauge and a micrometer to check the clearance but not sure where to go from there. Do I need to get the caps line bored and cut? Do I even need to worry about this at all?

Was hoping someone with experience can help advise.

thank you in advance!

technicalninja

All other cam caps have correct positioning markings?
Meaning you have caps marked as E3 and E5 in their respective positions on the exhaust cam...
If so then the machine shop made a Cardinal mistake and mixed your stuff up with another job at the shop.

If you sent that head in with the incorrect cam caps on it in the first place, then it's not their issue. They should have brought that to your attention BEFORE the head job was done.

No cheap way to fix that if a misalignment has occurred. There is a cheap way to check it, however.
I'd rip the valves and springs out of that side and bolt the cam into the head.
Does it turn smooth and easy?
You're probably OK.
If it does not and the machine shop mixed stuff up, call them quick, maybe the other job hasn't left yet and they can swap the original stuff back in.

Align boring camshaft journals take a true master machine shop with a wizard watching over the work. Probably easier to just get another head....
If the machine shop made this mistake ALL of the other work needs to be inspected by someone who knows what to look for (usually another machinist).

I have an AWSOME recommendation, but he works in Granbury Texas and shipping heads is not cheap anymore.

Afaraj

yeah all the intake caps are numbered correctly and all 3 and 5 are correct on the exhaust side.

The issue is I bought the head that way do I don’t know the history other than it was rebuilt. I can tell it’s been machined and it’s flat and seals well so I would hate to waste it and go looking for another one especially with prices now a days.

I plastigauged it earlier and can see that the two journals with the wrong caps are pretty tight ( reading .001) I still want to double check with a micrometer and bore gauge to make sure since the palstigauge is not giving me the most accurate answer.

was hoping someone would say that boring it is simple thing to get done at machine shop but by your answer it doesn’t sound like it.

yeah I’m in Georgia unfortunately so it will be pretty expensive shipping there and back 😕

technicalninja

I don't think my guy even has the machine to do this.
He will know someone who does and have a working relationship with them.

I'd do a spin test (valves out) even if the micrometer shows ok. Do it on both sides.
You will also get the chance to lap the valves in yourself. It's almost never done right.

If the head was warped more than .004 and they just cut it your journals will be out of alignment and it is so much better to figure that out before you install engine...

Cams spinning nicely in journals is one of my "pre machine shop" tests on anything I send to the machine shop.

A badly warped head needs to be "heat treated" and cooked up to somewhere around 400 degrees and then the head gets "reverse" bent in a press while it cools.
You can actually save one like this, but I don't suggest a head that has to be intentionally warped in a performance build.
Normal appliance car I've used this method multiple times to fix.

Afaraj

Thanks for the advice! I’ll try the spin test tomorrow. Saw on the Honda forums that’s what they do too.

I think I’m gonna take it to a machine shop to be checked out by a professional anyways but wanted to get some peace of mind that it’s salvageable before I get the funds to do that. This project started out with a goal of 220-240hp stock engine build and has spiraled so much due to my original engine being bad. I’m starting to think it might be worth it to just go back and build the bp05 head for the original engine instead of messing with this if I can’t find anyone close that does align boring for cams :/

Alejo_NIN

iTrader: (2)

if you really don't care about this and this won't be a permfornace head, you can try wrapping the cam journal in 1000 grit sandpaper with lots of oil. rotate it with a drill...yes, this won't be pretty and i would not dare do this on a car that will be abused..but if this is grandmas car, send it!
just make sur eit is not tight, betetr to have it "too loose" as opposed to "too tight"

if not, sell it for scrap..sorry bud, pay attention next time.

LeoNA

The BP4W heads are becoming hard to find and expensive, but the cost to repair this head makes it a losing proposition. The main issue is not the vertical oil clearance, it will be cap shift at the parting line. I have tried to save heads before by cutting the cap and re-boring them. It's not easy for me and I have had a fair amount of line boring experience. Good luck.

Afaraj

Well it’s official :/ I did the spin test and the cam binds. I removed the two incorrect caps and it spun freely. ( figured it was ok to loosen two caps in the middle since there was no force from the lifters as I had removed them) the two caps also don’t sit right all the way.

I tracked down the guy I bought the head from over a year ago and then he helped me track down the guy he bought it from. That guy races miata it seems so he definitely wouldn’t have made the mistake. He said he took it to a machine shop ( same one I was gonna use lol) and he was sure the caps were not switched so not sure what really happened. He did mention something about having it shaved by .006 which is but more than the fsm surfacing limit so i might just not look into it anymore…. Just feels like a shame to trash a bp4w head over to cam caps man

thanks for the advice all!

technicalninja

What part of the country are you in?
I'd try other cam caps before trashing that head.
Modern engines often have more "identical" parts than stuff from the past.
The correct position marked cam caps off another head are at least worth trying before you ****-can it.

The machining limits set forth by a manufacture are not the limit to what can be done.
As long as it was straight before milling, 040 off a head will not ruin the casting.

Now, you have to find someone else with a trashed bp4w head that will let you try his cam caps...

Afaraj

I’m in Georgia.

not sure how much that will cost just trying cam caps. They seem cheap enough on eBay I guess. This head was supposed to go in a 300+ hp build ( hopefully) so not sure if it’s worth it. I might just start looking for a bp6d or go back to my bp05 head and just have that rebuilt… would caps from an earlier head work on it?

technicalninja

Worth trying...
I'd be looking for a badly warped, trashed head someone was selling cheap or giving away.
I have a bp6d head that got so hot chunks of aluminum have vaporized around the exhaust seats.
It's complete trash and it cost nothing.
If you can get the proper numbers off of a bp4w those should be closest to working.

Alejo-NIN idea regarding the sandpaper will not work but...
If you use valve grind compound instead of sandpaper it will.