Rebuilding heads

[sotis]

Are parts for IH heads still available - ie. Valve guides, seats, welded rocker arm shaft bushings? Any reason why a worn rocker shaft couldn't be welded and then turned on a lathe? Anybody check their own heads for cracks with dyes, electro magnet? Thanks in advance for any info.

 

[Michael Mayben]

are parts for IH heads still available - ie. Valve guides, seats, welded rocker arm shaft bushings? Any reason why a worn rocker shaft couldn't be welded and then turned on a lathe? Anybody check their own heads for cracks with dyes, electro magnet? Thanks in advance for any info.

We currently have in stock all parts needed to repair any rocker assembly using some new parts and some reconditioned parts. We add items to the inventory as we can locate supply sources.

Since new rocker shafts have recently become unavailable, we're working on a rebuilding process which we will have done ourselves, a recent experience using another vendor for this has been less than satisfactory. Welding of the rocker shaft is not feasible (that is not the way a reconditioning process would be done), and cost of having the entire shafts and all it's variations reproduced is prohibitive.

We are also looking at having rocker bushings for welded rockers produced as the only commercial manufacturer of those items for the rebuild industry ceased production more than a year ago. Again, the bushing is only one part of the welded rocker arm solution, we have many used rockers with perfect bushings, but the valve tip pad is worn significantly. Reconditioning that part is fairly simple, but is part of an entire part assembly, not just a bandaid.

There are many subtleties to this whole "rocker assembly" issue and it's not a simple solution, this is due to some parts still being available but not in sufficient quantity going forward. And add to the issue the fact there are two entirely different rocker systems used on these engines over time, along with several variations of each.

As for head reconditioning, any competent machine shop can do this regarding the ihc-produced I-4/sv head sets. Key word here...competent. Head work on these items is certainly not any different than dealing with any other similar item. No competent machine shop would ever accept an ihc-produced head from a customer for reconditioning without first performing crack detection using normal commercial processes.

For myself I keep on hand a small "spotcheck jr." dye penetrant crack detection system from magnaflux/versachem. But using a system such as that for complete block and head inspection is not feasible. I do use it to "grade" cylinder heads before they are taken to the machine shop, I don't want to waste effort and cash to have heads magnafluxed if the combustion chamber(s) May have issues. And many 345 heads do have cracks evident in the combustion chamber area.

The I-4 and sv blocks do have particular areas that need to be crack-checked, I also do that in those areas myself before sending the block out for cleaning, magnaflux, and machine work. However, the "normal" cracks that May be present are absolutely no problem regarding engine functionality, and I would would never "scrap" a block that has defects in those known areas as they have no bearing on engine longevity/performance.

I can assure you that no one in the IH community has done more work regarding the "valve train/rocker assembly" issue than our crew here at ihon, that is very evident from the volume of threads regarding this issue in the three years since this forum was initiated. And no other vendor has put the effort into placing engine rebuild components on the shelf than we have.

Typical "rocker shaft" thread, go here:

http://www.forums.IHPartsAmerica.com/gas-engine-tech/5399-need-some-tech-advice-camshafts.html

And here:

http://www.forums.IHPartsAmerica.com/gas-engine-tech/5199-broken-rocker.html

We deal with this subject every day around here in one format or another!

 

[Michael Mayben]

Since this thread raised the subject of "crack detection", I thought I'd post this as it's timely....

Yesterday and today I've been going through some heads and other engine components to continue preparation for the engine build addressed here:

http://www.forums.IHPartsAmerica.com/gas-engine-tech/1144-ultimate-IH-fourbanger.html

I'd have to say...looking back over at least 10 years of dealing with various ihc-produced I-4 and sv engines, I've found about 50% of all 345 heads to have some sort of crack in the combustion chamber of at least one cylinder.

In going through a set of 345a heads yesterday,... When the passenger side was pulled off, I immediately noticed the anomaly seen in this pic. Definite clue something was amiss.

This engine has been torn down in the past and it appears that the heads have been surfaced at least to clean 'em up. From the internal appearance of the crankcase and heads, it's obvious nothing was really cleaned, most likely a simple valve job and head gasket/intake gasket replacement.

This shot shows the combustion chambers for cylinders #6 (on the right) and #8. See the difference in appearance??

 

[Michael Mayben]

Doesn't take a magnaflux process to see what's wrong here!

The crack from the intake valve seat over to the spark plug boss is the most common crack location I see regarding visual inspection of these heads.

This particular engine had coolant seepage into the combustion chamber. The engine could have run many hours like that with a continuing loss of coolant that could not be located.

If...a cooling system pressure check had been conducted both cold and "hot", the loss of pressure would have possibly been observed. No doubt a cold engine would have exhibited a misfire on that cylinder until warmed up, most normally blamed on a "bad carburetor", bad spark plug, bad whatever.

A test of the coolant for combustion gases present would have been a definitive test but would not isolate which cylinder(s) had issues. And experienced mechanic most likely would have been able to isolate which bank had a problem but only a teardown would show the root cause.

This cylinder head is repairable by a pro machine shop but that procedure is costly and normally undertaken only when decent used head cores aren't available for whatever reason. I'm not a fan of "stitching" head cracks, id much rather have a pro do a weld process, then have a replacement seat insert installed along with a replacement guide.

 

[Michael Mayben]

So moving on to the other head of the pair (hoping I'll get at least one good core), you can see that the coloration of the combustion chambers here shows no obvious coolant leakage. But one of 'em is "different", the shiny/slick finish instead of the normal sooty surface we'd expect form a cylinder operating correctly.

Cleaning with the dremel rotary brush and carb cleaner shows what appears to be cracks on all four holes here, from the plug boss across to the intake valve seat! So out comes the spotcheck jr. Kit, I know exactly where to look for cracks, so those areas are the only places that will be tested.

 

[Michael Mayben]

While waiting for the penetrant dye to set up, I take a look at the head gaskets, the head surfaces show definite evidence of combustion gas leakage across adjacent cylinders.

Sure enough, the head gasket fire rings are going away and the composite paper material is definitely breaking down, hard to see that in this pic.

 

[Michael Mayben]

After applying the developer, the crack really jumps out at ya!

So this chamber was not allowing coolant penetration...yet. But no doubt if the engine had been run longer, it would open up.

Two other chambers were ok, the last one has a surface crack visible to the eye but the dye penetrant won't show that since it can't "penetrate" the crack, only a visual inspection will show.

One of the largest engine core parts wholesalers west of the mississippi is up in troutdale. Those folks tell me that well over 1/2 of all the ihc heads they attempt to salvage for cores (resale to commercial engine builders) have these same cracks but that the 345 heads are the worst. All parts they reclaim for potential cores are fully magnafluxed before shipping to their customers around the world.

 

[MarkO]

What is different about the 345 heads that would cause the cracking problem?

One would think it would be a problem for all sv engines since they are all so very similar.

 

[Michael Mayben]

what is different about the 345 heads that would cause the cracking problem?

One would think it would be a problem for all sv engines since they are all so very similar.

I've discussed this "head crack" issue with several folks in the automotive machine shop bizz and a few former ihc employees (not dealership personnel). All have opinions and ideas, none have a definitive answer.

But then, this kind of deal is not exclusive to IH stuff, it's across the board with many engine series from all manufacturers.

 

[sotis]

Thanks for the good info and pics - two questions, are the "a" engines less likey to have head cracks than the "e" engines and are the steel head gaskets still available?