Alright so im posting this becuz ive heard nothing good about this shop, and unfortunately I didnt do the research before I bought the head. I bought a gsr JG head port and polished, and with JG's complete valve train. I bought it with 0 miles and for a relatively good price. I haven't gotten the head checked at a machine shop, but i want to hear some feedback from you guys. Is this head worth even getting it checked? how good/bad is their valve train? I have read many threads about Javier's shop being shady cuz he never ships blocks/heads, I have the head on me so thats not the problem, I dont really want to know about how he has screwed ppl over like that, I want to hear from those that actually have used his heads or have seen his heads in use. Will his head hold up a good 500hp easily without worrying about it giving out? I need to make sure before I slap the head on my block. please give me some feed back

 

you're in the all motor section. No motor you build here will pump out 500hp so I wouldn't worry about it. Doing buisness with JG was the problem and not getting your parts. Since you already have the head, you can have someone else look it over if it makes you feel better but you're probably good to go as you are. There's really nothing anyone is going to say here that's going to make any difference one way or the other at this point. Either run the head or pay someone to tear it all down and reassemble it to make sure everything is good.

 

Yea I know I'm going turbo, just posted on this section cuz I figured some ppl have probably ran his head.... and I just wanted to see what ppl had to say about his heads.... I know he has shady a business by not responding to ppl, but what I'm also worried about is his valve train, how can I tell it has titanium retainers? It does have dual valve springs, and the are his valves good? And this may be irrelevant, but when u bend a valve, is that due to a shitty retainer, valve spring or valve?

 

when u bend a valve its becuzz ur valves hit the pistons..

 

or hit eachother. I would be more concerned about spring pressure, you dont want valve float at higher boost levels.

 

If its a real JG head, the porting has never been a problem.

(I used to be a premier JG dealer back in the days). The valvetrain components (springs, retainers) are not bad at all, neither are the valves they used.

The ONLY problem we ever had in all of the heads we sold (somewhere around 40-50 units) was one had valves that did not seal, so we simply lapped the valves, and the head went on to make great power.

Now I am NOT advocating JG's practices, and have had horrible experiences with their blocks...almost every one we got dropped sleeves. The heads have been tried and proven, and have been on some record setting cars in the past. I would suggest taking it to a machine shop, check the valves to make sure they seal, and give it a good once over to make sure nothing looks fishy.

Look for the JG stamps, and if its a newer head they did, on the part where the distributor bolts up, they started putting serial numbers...if it has one, give em a call to make sure its a real JG head.

Again...I AM NOT A JG ADVOCATE!


Just had tons of experience with them in the past.

 

One thing that should be noted is that when a head has been ported and received a new performance valve job, the valves typically won't seal until the head has been heat cycled a couple times. So if you check them before you bolt it on and run it, they probably won't seal. If you lap the valves in to make them seal, you'll probably mess up the vlave job and lose some flow.

 

Yes it does have the JG stamp on it, and where the distributor bolts up there is a serial # "7034" and yea I did read a lot about their blocks going bad, nd didn't find much on their head,s and that is precisely on what I'm worried about "valve floating" at high boost levels, and so I'm a bit confused, what do u mean by stating that the head has to be heat cycled? How do I do that before/ after I bolt on head? So lapsing the valves after a fresh port job will actually affect flow? So what do u recommend I do?

 

Heat cycling means you bolt the head on the motor and drive it/tune it whatever. The motor comes up to operating temp and then you allow it to cool off normally. It's kind of like a break in period if you will. I recommend you do nothing but install the head, adjust the valves cold and then run the car/tune it and test the compression/leak down if you want after a week of driving it and see how things look. You really don't need to worry about that much.

 

Ok thanks for the help, I just wanted to make sure, cuz oh all the bad things I read on jg, that is what ill do, ill bolt on head, break it in and then have a leak down test performed. Thanks