How scored is too scored (Cylinder head fun time)

[captdistraction]

:

So the deal is this. The car is being torn down for race use, and I'm revisiting my motor issues (long drama, but its a MMR built motor that currently has ringseal issues and low rpm low oil pressure issues).

One of the side effects (or more likely the cause) of the latter is this:




Now I understand I have a few choices (aside from whatever I do or do not work out with MMR, they're aware of the scoring and felt it wasn't a huge issue to just continue to run this way. I obviously feed different):

1) Replace the Boss 302R heads
2) Line Bore the head, insert bearing (~$1000 once done, no guarantee on true alignment of the bores)
3) bore base of head, shave cam cap, clean its surface (now the geometry has changed slightly, same money as above)
4) Buy some 1k bare castings for Boss 302R heads, move my valves over and other gear.
5) See how long it is until the valvetrain fails (my luck estimates halfway into first race)

+ all have new cams being purchased as well.

Anyone have thoughts on these otherwise expensive doorstops?

 

[BigTaco]

I would get new complete assemblies at this point. You may end up stepping over a dollar chasing savings. All that ran through the whole engine btw....

 

[VoodooBoss]

Yikes. So much for the bullitt proof MMR engine. Will you be racing in the same class as Drew?

 

[captdistraction]

yeah I will be. The castings are on ebay. I am really thinking about just securing them. I hope I can con MMR into helping out, but I won't hold my breath.

I may or may not be resleeving Drew's old shortblock. Between the ring seal issues on mine (blow-by, heavy oil consumption) and the 11.5:1 being a bit tough to tune for fuel availability, going to a 11:1 setup might make a lot of sense in the long run.

I like to learn everything the hard way. Hopefully have this all figured out soon.

 

[BigTaco]

I would get new complete assemblies at this point. You may end up stepping over a dollar chasing savings. All that ran through the whole engine btw....

You may end up stepping over a dollar to pick up a dime, is what I meant type...

 

[Berol]

4) Buy some 1k bare castings for Boss 302R heads, move my valves over and other gear.

With this being essentially equal money to the other options, I'd just go this way.

Makes even more sense if you are going to use Drew's short block. Just slap the new heads on his short block and move on.

 

[Grant 302]

My only suggestion: Do not reuse that cam, cap or head in any plan.

 

[captdistraction]

I bought the set on eBay. I'll replace the cams and I hope the castings have the caps on them as I imagine they're machined together.

I'll move the valves over, not sure if I really need to buy new springs etc.

Sucks for my credit card, lol.

 

[Grant 302]

I'd rather have new springs considering the relatively low cost. But I understand taking a pass on extra cost when already over budget. :-\

 

[captdistraction]

Springs are fine. I can grab a set. I have to decide on which cams. I'm running factory boss cams on both sides. I have long tubes, but I'll also be limited on power to weight for the build.

 

[captdistraction]

Now to find the intake cams. Found the exhaust ones but no real deals exist on the stock intake cams. Anyone upgrade theirs and have the stockers laying around?

 

[Grant 302]

I thought I saw a set of stock boss cams and other takeoff parts in the buy n sell section not too long ago.

 

[steveespo]

I bought the set on eBay. I'll replace the cams and I hope the castings have the caps on them as I imagine they're machined together.

I'll move the valves over, not sure if I really need to buy new springs etc.

Sucks for my credit card, lol.

I bought a set of those heads too, waiting for shipment. The bearing caps come with them. You need everything else including cup plugs and spark plug tubes. For $750 you can get all OEM parts except for the spark tubes. I don't know where to get them as they aren't serviced separately. Dean Martin is asking around for me and I have an email into Watson Racing. If anyone has an old damaged set (captainD) please check if you can remove the tube without damage. If you do, I would buy them from you too. (captainD is going to need his).
Thanks
Steve

 

[ArizonaBOSS]

Well...let me know when you want to borrow the valve spring compressor.

 

[captdistraction]

I bought a set of those heads too, waiting for shipment. The bearing caps come with them. You need everything else including cup plugs and spark plug tubes. For $750 you can get all OEM parts except for the spark tubes. I don't know where to get them as they aren't serviced separately. Dean Martin is asking around for me and I have an email into Watson Racing. If anyone has an old damaged set (captainD) please check if you can remove the tube without damage. If you do, I would buy them from you too. (captainD is going to need his).
Thanks
Steve

Gotcha, since I have assembled heads already, I'll see if I can get the spark plug tubes pressed out of them while the old set is cleaned up (as I'll sell my old set, I imagine someone will want to try to work with them).

I'll probably get new springs and valve seals as that only makes sense, and move my keepers, retainers, valves, lifters and rocker arms over. I don't have the rocker retaining clips as MMR discarded them, but I can't seem to find a part number for them (according to MMR they're just for retention during factory assembly, is that so?)

On the plugs, how much of a search is that going to be? I have a MMR rear crossover bridge (yeah yeah) that can at least cover the rear plugs

 

[captdistraction]

looking at the tubes, I think they can be pulled with just a torch around the body:

Being so thin, I can't imagine its a high-pressure press fit.

 

[steveespo]

See what you can do to get one out. I don't know how tight an interference fit they are A) Because I haven't been in there yet and B) why would anyone have to take one out?
Dean was a bit puzzled where this Custom Built Motors got the castings from without them.
Steve

 

[302 Hi Pro]

Hi Captaindistraction:

Sorry to see the pics and to read about your exhaust cam journal failure. You made a good decision to pull the trigger on a new set of cylinder heads as this cylinder head, as shown would require major machine work to salvage.

I was really surprised to see your comment about MMR was aware of the scoring and felt not an issue and continue to run it this way. I totally agree with you, and have different feelings as well!

Did you disassemble the bottom end for inspection? If so, how do the cylinders and crankshaft rod and main journals look? Thanks for sharing and good luck with your rebuild.

Dave,
302 HP

 

[captdistraction]

I haven't torn down the block yet, but there are the following issues that make me think I'm not getting good ring seal:

1: smoke on decel
2: oil always smells of fuel
3: the breather setup would always smoke under idle or when I lift (could see it leave the vents on the tiger hood at slow speeds or at a stop). So much so that I put the factory PCV system back in.

I'll know soon on the tear down. Still going to see what's on the table with MMR before I make any decisions, though I should have those head castings in hands soon.

 

[ilesjohn]

That scoring of cam journals looks like something gave way and was traveling through the oil system, bearing material or some other metal in the oil