I'm in the process of putting new heads on my car, but they're junkyard heads that I've had machined (screw-in studs, valve job, guide plates, etc.). There is a crack in one of the heads that originates at a bolt hole and goes about an inch into one of the combustion chambers (on the flat part of the head). My machinist noticed the crack and punched little impressions along the length of it, attempting to stop its increase. He also put a sleeve in the said bolt hole. The head passed a pressure test. He said that it should hold up, but if I'm really worried then I should look into something called "Lock-N-Stitch." Basically, it's a way of repairing cracks in metal, especially cast iron. The machinist doesn't have the capability to do the repair (the tap alone costs over $70, he said).

Unfortunately, all of the machine work was done to this head after the crack was noticed. Why, I don't know, but it doesn't really matter now. Has anyone used Lock-N-Stitch before, and does it work? I'd like to use this head if I safely can, because I've already invested a lot of time and money in it. However, a crack is a crack, and I know it shouldn't be there. Am I better off just finding another head and starting fresh?

 

I vote for finding a good used head.

 

I second the motion to acquire another casting. Have the necessary machine work done, and transfer your existing hardware over.

 

i'd question why your machine shop continued to work on the head after finding a crack wihtout your approval?

 

i would also question why a machine shop didnt notice the crack before they started to work on the head ...

any good machine shop will check for cracks before beginning the process not only by pressure testing but a good visual too....

id get another head and start over i know it sucks buy why take a chance on it ....

 

Unfortunately for you, this is the reason I always preach about getting all parts, especially used, magnafluxed before putting a dime into them.

Any decent machine shop would INSIST on this.

At the 2 shops I use all the time, and have for years, they won't even give ANY estimates on machine work on used parts ( blocks, heads, rods etc ) BEFORE doing a vat job and a magnaflux.

You CAN have the crack welded, depending on how size, location etc...but that is NOT cheap.

This may sound crappy, but your best bet is to find another head and use all the hard parts from the cracked head, and have ANOTHER machine with some sense, rework the replacement head to match the other.

 

Thanks for all of the insightful replies, guys. I'm actually dealing with another machine shop now, because my original machinist just quit the other day (from what I understand, the working environment just wasn't very enjoyable).

Fortunately, and I mean fortunately, I was able to find another '601 casting locally, costing me only $25. It was already magnafluxed and pressure-tested, too. I purchased it from the same place that my original machinist bought the other replacement head when it cracked in the tapping machine. That one was already checked for problems.

This will be the fourth '601 head that I've ported, and the sixth ported head overall in this project alone. Just for fun, I'm going to illustrate all of the crap I've had to deal with since March. Not a rant, not a vent, but something to look back on and smack myself for . If I only would have bought long-slotted rocker arms!

The infamous "brake job" (should be "break job"):

- All I wanted to do was fix my brakes, so I did. In crawling under the car, I noticed that the rear intake manifold gasket was leaking oil
- Fixed intake manifold
- Blew head gasket on initial startup (two-year-old overheating incident finally caught up to me)
- Minor repair turned into engine overhaul "because I have all spring"
- Pulled engine, machine shop became backlogged
- Ported stock '083 heads
- Reinstalled engine using high-lift cam and stock rocker arms, cracking numerous studs
- Replaced studs, only to find that the '083 heads were stressed and cracked around the stud bosses
- Pondered, tried JB weld and a mechanical fix, felt sick
- Sucked it up and pulled heads, bought new heads from eBay, only to find out that the seller lied and screwed me out of $200 (still trying to rectify that). '193s are NOT '083s, no matter what they say.
- Went to junkyard and found first set of '601s, ported the hell out of them
- Head #1 cracked at machine shop, replacement purchased and re-ported and re-machined.
- Crack in Head #2 found after machine work was all done
- Machinist quit
- Second replacement '601 purchased
... and the saga continues

Needless to say, this has been a little disheartening, especially since this is my first complete engine rebuild. Kinda makes me wonder if I want to do it again... I think that my luck is finally changing for the better, though. Words of advice: 1) It can ALWAYS be worse than you thought. 2) Learn from your mistakes.

I have five hours to port out a set of heads if I want to get them to the shop for tomorrow. Time to break some records...

 

sounds like a bad soap opra ......LOL....good luck with the new head hope this shop wont screw you over like the last one did

 

I have been down a similar path 7 or 8 years ago. The hair I didn't pull out was eventually falling out on its own. I will only buy new cylinder heads from now on. Freshening my own is ok, but after going thru what I did, new is not as expensive as it seems. After wrapping up $2400 in a set of stock castings I wanted to puke.

 

id guess so ....LOL....wow thats horrible to have that much in a set of stock casting heads........

 

Floor guy, I don't know what to say... $2400 in stock castings would have make me puke, too. I have a little over $1000 invested, taking into consideration parts, labor, four pairs of heads, etc. Losing the money is one thing, but lost time is important to me, too. I'm about four months overdue with this thing. It was disgusting watching all of my buddies driving around their fast cars this summer, while I was tooling around in a four-cylinder Jeep.

I think that I'm going to go the "new heads" route next time, as well. For less than $800 I could have gotten a decent set of S/R Torquers, ported them out, and have still probably made more power than with these stock castings. Plus, you get that warm fuzzy feeling knowing that they're brand spankin' new.

I managed to fully port the remaining head in three hours -- when you're angry and fueled by adrenaline, anything is possible . The shop will have them tomorrow morning. Ideally, I'll be able to pick up the completed "good" head in the evening, put it on the engine to check pushrod length, and place an order with Jeg's. The other head could be done by Friday.

 

I learned alot from my screw ups! One thing I especially learned is not to pay $500 for a set of used castings. My $2400 included the roller rockers($330) and head and rocker bolts and guide plates. ($100) Combine that with poor machine work and the price shoots thru the roof. Throughout the whole process you keep thinking another couple hundred will fix it. When it is over you look back at the receipts and puke. Note: NEVER use a machinist who has bi-focals that are an inch thick. If you see him squint at his DIGITAL mike run!. Also the beer in his other hand was a sure sign. Hindsight is 20/20.