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Old 04-03-2015, 04:07 PM
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powderpig powderpig is offline
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Default Gunn Automotive

Hello all.
I wanted to tell you all about a recent experience I had at Gunn Automotive. I have for the most part used Mountain High Performance for most of my engine rebuilds. Well I had a 1 FZ I need done quickly, and MHP could not accommodate me. So I hauled it all off to Gunn. Well, all went quickly and I thought all was good. Before I went to Gunn, I called Gunn, and I had delt with JT for this deal. I did not know JT (I have had some dealings with Gunn for 2UZ V-8 heads twice last year, JT was not there). Well, JT had told all that was done, and I had a pause when he told me he turned my stock Toyota pistons into a Full Float system at room temp. Well, Toyota Spec's are for the piston to wrist pin bore to be full float on these pistons at 170-190 F degrees. These pistons are not designed to be full float at room temps. So JT had informed me he has been doing this for customers for many years(all Toyota Pistons he worked on).
Anyhow, after talking to Kenny(Younger son of Ken and brother to Phil(who I thought was the current owner)). Anyhow I got it all worked out, and they did me right in the end, but after talking for quite some time.
So I found out about 2 week later that JT and Kenny are the new owners of Gunn Automotive. So Phil has retired, and sold the business to JT and Kenny.

So I guess I am warning you all that use Gunn, to tell them(JT or Kenny) when you come in, and have machine work done, you want Toyota factory specs on your pistons, not a full float on a piston that is by Toyota's Specs to be garbage at room temp. Other wise their work was spot on, and very acceptable.
I would use them again, but I would also need to have a good conversation with them If I gave them pistons to make sure I get what I want.
Thanks for Reading.
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Old 04-03-2015, 07:44 PM
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I just had the lower end of my Isuzu 4BD2-TC into Gunn. I had talked to Phil late last summer about the job, but I ended up needing to put a new roof on the house, so the whole project got delayed.

When I went back there in early March to confirm them doing the work, both Kenny and TJ met with me to discuss the job and were up front when I asked for Phil, that he had retired at the end of 2014. In my case, TJ is the lower end guy, he was very interested in the 4BD2-TC as although similar to many diesels that they had done, but that particular block was not yet on their resume.

TJ was in touch with me several times via phone and email regarding the progress and suggested that I should also replace the cam bearings too. I had not provided the cam bearings with the other parts that Phil had suggested I provide to them.

I just picked everything up Wednesday, so I don't know all the results yet. But, I do know that TJ checked the tolerances on everything closely, I provided him with a copy of the FSM, and even called Mountain High Performance about one crank dimension not specified in the manual he was concerned about.

I believe that Kenny and TJ want to be sure to continue the good reputation that Phil has developed over the years. I will report soon about the results.
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Old 04-03-2015, 08:48 PM
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Thanks for that feedback Robbie
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Old 04-03-2015, 10:11 PM
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Quote:
Originally Posted by subzali View Post
Thanks for that feedback Robbie
x2

I don't do machine work often, and when I have I've also used Mountain High Performance, but the float at room temperature thing would be the type of thing I wouldn't know about, since the engine would likely be buttoned up. It *probably* wouldn't manifest itself for quite some time as a problem, but since my engines don't run at room temperature, eventually I'm sure it would wear.

There are some projects where I will gladly take some preferences or non-factory practices as quite alright (like on a chevy 350 if I had one--because I don't believe their engineering to be as good as Toyota, and because every machine shop probably knows them very, very well), but I am a Toyota nerd for a reason.

I have an engine (the 2LT-E) that I have quite literally run out. No bearing failures, no funny noises--I've just put so many miles on it that the rings are just plain worn out. I don't think you get that kind of mileage (approximately 300K out of the 2LT-E) by deviating from the factory specs.

Dan
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Old 04-11-2015, 10:58 PM
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Rzeppa Rzeppa is offline
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Wow, being a DIY tech nerd, I have to ask, what is "full float bore" on wrist pins? I know what wrist pins are, and I know that holes in metal parts enlarge at increased temperatures. But the only full float terminology I am familiar with is of course axle bearings, not wrist pins. Is it some kind of torque measurement to twist the pistons on the rod?
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Old 04-12-2015, 09:31 AM
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Quote:
Originally Posted by Rzeppa View Post
Wow, being a DIY tech nerd, I have to ask, what is "full float bore" on wrist pins? I know what wrist pins are, and I know that holes in metal parts enlarge at increased temperatures. But the only full float terminology I am familiar with is of course axle bearings, not wrist pins. Is it some kind of torque measurement to twist the pistons on the rod?
Pretty much.

When the wrist pin is said to be a "full float fit" it means that it slides around and rotates (in all axes possible). Machining the pins down so that they float fully at room temperature is often referred to as this.

It's done on some race and hot rod engines under the assumption that the engine will be taken apart regularly, so you don't need a press or to heat the parts in order to take them apart or reassemble them.

Toyotas start with pins that aren't full floating, and after a few miles (or a few hundred thousand miles) the pins wear to become naturally fully floating even at room temperature.

The reason I wouldn't want mine to start as a fully floating fit would be that I believe that to be a wear item, that's supposed to be tight when cold, and loosening up only at temperature. Starting loose means they will just get more (and probably excessively) loose at temperature.

Dan
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