Irv Gordon’s 3 million mile Volvo P1800 had had three engine rebuilds. The third engine rebuild has gone over 2 million miles. Why did the third rebuild last so much longer than the first two? The answer is residual stress relief. The cast blocks get residual stresses imparted from the cooling process which propagate to the surface and are “relieved” with use.
In the old 50’s and 60’s Nascar days the engine builders used to look for seasoned blocks. These were blocks that had been used for 50,000 miles. They claimed the seasoned blocks lasted longer and made more power. I know they were quite serious because they paid a pretty penny to get these, often purchasing the entire car or truck to get the engine block. A seasoned block is a block that has been stress relieved. Modern Nascar teams use a vibration table and/or cryogenic treating to accomplish the same task on blocks and heads. No secret here, you can see the equipment in their shops.
Cryogenic treating works by relieving casting stresses, which causes parts to keep their shape after machining, AND imparts changes within the grain and grain boundaries that improves abrasion and wear resistance. There is quite a bit of PhD level information on the subject if you Google it and are able to understand it. The process is completely different than the changes we see in steel/iron grain structures from heat treating and do not show up with a Rockwell hardness test. Cryogenic treating improves the toughness of many iron/steels but does not change the hardness. The same is true for aluminum. The fact that cryogenic treating is used for helicopter and turbine parts (Google it yourself!) should be proof enough that the benefits are real. Whether the cost/benefit is worth it to you is the question.
So academics, racers, and hard core aerospace engineering have all proven that cryogenics can improve material properties, but what is that worth to you? Well, there are no billion dollar government funded double blind studies showing that your hot rodded Chevy 454 will last twice as long with cryogenically treated parts. You just have magazine articles (always a suspect source), and word of mouth from people who have tried it. For me, I treat every engine block cryogenically. It costs $200 and I am gambling that I get twice the lifespan for that $200. Depending on the job, I am highly tempted to get cylinder heads treated as “word on the street” is that they don’t warp after cyro treatment. Every Alfa Romeo owner needs to try this and report back to me after 50,000 miles.
As far as cryogenically treated brakes go…. Having the brakes start to pulsate during a race or track day is a common problem with street and vintage cars I work on. For every car I have installed cryogenically treated rotors or drums, the problem has disappeared, except for my 2007 Ford Mustang GT which needed larger rotors up front to get rid of the problem. I have cured five cars with the chronic pulsating brake problem by using cryogenically treated rotors or drums. Whether cryogenic treating will work for the OP’s truck and driving conditions, it is his unique test he needs to perform. I have heard enough people with first hand experience tell me cryogenically treated rotors solved their issues to be sold on the process. Sometimes you have to get off the fence and make decision, and I think there is enough info out there to make that decision in favor of cryogenically treated rotors.
So, enough about cryogenic treatment, what about coatings? Well I resisted coatings for a long time, but I am going to breakdown on my next job and coat lots of stuff. Here is why:
1. Thermally coating the exhaust valve face reduces its temperature several hundred degrees. I only know this because David Vizard told me so. I figure David Vizard knows his stuff and knocking a few hundred degrees off the valve temperature has to be a good thing for longevity.
2. Most manufacturers are shipping cars and motorcycles with anti-friction coatings on the pistons. So that must work pretty good and be cost effective.
3. KTM and Honda both ship engines with DTC Diamond coating, or the equivalent, on the valve follower/cam interface. So that must work and be cost effective.
4. Porsche and Subaru both use thermal barrier coatings on their exhaust ports in their turbo race cars. I know because I have seen them. So that must be good stuff. Porsche even uses it on at least one of their 911 street cars, so it must be somewhat cost effective.
5. A few cars are being shipped with coated main/rod bearings, so I figure that those coatings must actually do something good or they wouldn’t be paying for it.
6. You don’t need a degree in thermal engineering to figure out that coating the exhaust headers reduces underhood temperatures by about 30-50 degrees. That has to be a good thing with all the electronics they put in there these days. $400 well spent in opinion. At least it is well spent here in Southern California. Some Canadians may feel they need that extra heat.
7. The jury is out when thermal coating piston tops and cylinder heads. Some say it works great , others say you need to the heat to dissipate as much as possible. Seems like a gamble to me. What I would like to see is a coating that prevented carbon build up in the cylinder. I’ll be some OEM’s would pay for that too.
8. The thermal dissipating coatings work well. If you have an air cooled cylinder head and you get it coated with that special black thermal paint stuff, your metal temps under the spark plug are going down around 15 degrees. I know because I tried it and scientifically measured it myself. More than once. That’s real hardcore science for you right there.
So there you have it. What has pushed me over the edge with thermal coatings is that I have seen the manufacturers start to pick them up. I figure if they are doing it, then the benefits are real enough for me.
