Does anyone know if there are machinists that can line bore the cam towers on 4.6 heads? My heads are in perfect shape except for the fact that the cam tower bearing surfaces are scored. It would seem to me that it would be a relatively simple operation to surface grind the mating surfaces and than line bore the towers to the original diameter. Unfortunately I have not been able to find a machinist in the NY area that has the equipment or experience to do so.
-RoughKnight
And here-in lies the big deal.... First - we need to trim the caps and the mating surface on the cylinder head...
After that, do we need to torque the head to a plate to simulate torsional stress when we line bore the cam journals? How anal do we get?
When I see these kinds of problems, I simply go with a rebuilt head - big reason is becasue the rebuilder carries the warranty. Sending the bulk of the concern "up-stream" isn't a real bad thing....
Actually I agree with you and I did initially job out my fully assembled heads to a machinist to be reconditioned. $450.00 later I got them back with scored cams and metal filings in the oil galleys. I than tried the cylinder head exchange routine and ordered a set of rebuilt heads from Alabama cylinder heads. The heads arrived fully assembled with cams. the cams were okay but the clearances were .004 (not within tolerance) and the bearing surfaces were scored in addition the head was filled with aluminum oxide grit and/or glass bead. So I am back to the original heads. At this point if I cannot find a machinist that can line bore the heads I will have no choice but to use them as is with new cams. (the clearances are within spec with the scored bearing surface and scored cam journals. The way I see it if I replace the cams at least they will not continue to abrade the bearing surfaces and since the clearances were within spec with new cams the clearances should only be better. As far as warranties are concerned The heads would have easily lasted about 10,000 miles or more, but in both case the metal filings /or grit would have wiped out the lower end in short order. As far as rebuilding engines we get anal to .0005 (or whatever the tolerance is if we don't then we have no business rebuilding them. furthermore delegating the responsibility of rebuilding a head to a machinist does not absolve you of the responsibility to insure it was rebuilt to spec and within tolerance.
wrote in message news:NSc7l.1442$PH1.744@edtnps82...
With cast iron, cam in block heads there was little need to get anal over "street" heads though I always made sure I was delivering a product that exceeded factory requirements...
Get into multi-angle valve jobs, replacing guides or seats - of course the price went up. But we were still working with an iron head... It wasn't hard to find a machine shop that could Blanchard grind an iron head... (for the benefit of the less experienced... grinding ferrous metals is a LOT different from grinding aluminum). Doing multi-angle valve seats was only limited by the customers ability to pay for labour and the shops ability to buy stones...
New materials and new manufacturing techniques limit the small shops ability (or profitability) when it comes to what we expect them to be able to do... My personal tool budget for a year would be enough to curl someones toes... The tool budget I am entrusted with for our store would curl many toes many times over...
Little wonder when a a complete factory scan tool (a Toughbook based IDS) is about $7G CAD not including the subscription fee....
Little wonder when the tool I choose has to withstand hundreds of cycles compared to the 5 or 10 expected from a DIY tool.
Little wonder when, so many times, Ford sends us a tool stating "we need it" because "we sell ". Oh, and the tool is not going to be cheap.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.