SIM head rebuild

[crimsondragon]

Unfortunately, my experience with them was far from spectacular. There are pros and cons and I will give a fair judgement. Scroll down for cliffnotes since this is a long read

Background:
This head came off of my 2g. I had a 6 bolt swap waiting so before I had it sent out, I had the bolt holes drilled out to 1/2" to accommodate 12mm headstuds. I put it off until they had a sale right before the Shootout this year. That's when I decided to ship the head in. I had a piece of paper listing all the parts I was sending in as well as contact info and what I was looking for out of this head.
The parts included:
2g head
272 regrinds w/ #10 washers
engnbldr's SS valves and bronze guides
Evo valve springs and retainers
lifters, keepers, rockers, cam caps

I told them I was looking for a rebuild with the standard works + decked surface, and a stage 1 port and polish. I pm'd the vendor on here and informed him of a package heading his way. Allen called me when they got it and got to business. He verified with me what I was looking for and informed me of the subtotal. I asked a few of my own questions and was sold on a stage two port and polish instead of a stage 1. He informed me due to them attending the Shootout, it would take longer than usual. I ok'd everything and paypaled the total the next day.

A month goes by before I decide to actually give them a call. However, Allen reached me first on that day. I was informed that the head was ready to be sent out. He also informed me of a mishap where a casting flash broke off inside the head and was stuck. At first I was a little worried but he reassured me it would not affect anything or come out as they tried to get it out by running water and air through the passages. I was still worried but I ok'd it. He also mentioned he added a little mod to the oil passage by deepening it. I thought it was a nice touch.

When I received the head, I gave it a quick once over and verified the ports, cleanliness, cams, etc. I also verified that indeed something was rattling inside the head. I thought of buying a borescope to have it checked out. Unfortunately, life happens, and I was still working on the suspension and brakes of the car so the head was put on the backburner till the time came which is why I am writing the review now.

With the brakes and suspension done, I figured it was as good of a time as any to start assembling the head and block together. I took the head out of the box and started the detailed inspection. Here is where the ugly starts to show. The stage two port and polish includes opening up the combustion bowls and smoothing everything. Upon inspection of the bowls, two of them seem flawed. One still had the casting flaws on the edges and they were relatively rough. First thing that popped into mind was that these could cause hot spots. No problem, I can just filed them down a little which is what I did. The other bowl had a whole rough section that seemed to have been missed. This included cast pits and everything. Not too pretty but is workable.

I inspected the rest of the ports and moved into the assembly area. Cams were lubed up well. Valves were labeled in accordance to either respective cylinder number and everything seemed to be assembled properly. I inspected the deck and admired the oil port mod. It was then that I noticed the bolt holes seemed rather small. I went and grabbed a 1/2" bolt I had laying around and started prodding each hole. Would not fit into any of them. I flipped the head onto its side, exhaust facing me. On my old head, I had a broken stud. I drilled and easy-out'd it but during the drilling process I nicked the edge of the threads a little. As confirmed, the nick is not there. This is not my original head. I got some stranger head in my house with a rattling casting inside it.

Obscenities were shouted. A couple face palms, and thumb and index gripped the bridge of my nose. This irks me a little as I did put a little bit of time and sweat (no blood spilled) into the head so it felt personal. I'm irked that I sent in a head which I can then imagine was tossed up on a shelf as a core and when my order came up, they just took a head that was next in line. I'm also humored a little that somewhere out there, is a guy with my head who I can imagine is putting on his 7 bolt and is wondering why the oil pressure seems a little low. Or it's a 6 bolt and is happy it slid down the studs easily. Who knows.

Now that the cat is out of the bag, my worries are back with a vengeance. The next check I could quickly do was to see if all the parts are there. Everything I could quickly see and count right off the bat is present but what about what I couldn't see? Regrinds are sent with #10 washers to be put under the lifters to make up for the smaller cut dimensions of the cam. I chose a random lifter and checked underneath. Washer not present. More obscenities, face palms, and massaging of the temples. I did mention they were regrinds to Allen. I did write down #10 washers on the parts list. And I definitely did send it. So apparently whoever built this probably saw the washers and were like "WTF do I do with these?" and tossed them into a hardware box somewhere. Not even have the decency to throw them back in with the head so now I'm out 16 washers.

Now I'll have to check everything on this head. Cam cap torques, springs, retainers, valves, seats and guides and straightness of the mating surface. I'm going to run a fine tooth comb through it and see what other surprises there are. I will update this later on and will have pics up.

Cliffs:
Sent 2g head with drilled out holes for 12mm studs with plethora of parts for rebuild.
Received head. Head is not original. Holes are not drilled out, casting flash broken and rattling around inside. #10 washers missing from underneath lifters for regrinds. Combustion bowl port and polish subpar.

Overall:
Not for nothing, my opinion on this is that these guys are new. Mistakes were obviously made. With all new companies there seemed to have been a lack of communication within causing certain details to have fallen through. I'll give them the benefit of the doubt as I seriously hope they don't take heads that are shipped in and toss all of them on a core shelf. That would be pure evil in my opinion. Communication with the customer was excellent. I've had experiences on both side of the spectrum and I would say they are top or near the top. The port and polish work of the runners is excellent. No flow charts but with the depth they went into it is not needed. The bowl work not so much. Missed spots here and there.

I won't comment on anything else till I have fully examined the rest but this is my verdict so far: great for guys with a budget and just want it done. Not so great for guys with attention to detail and/or looking to break the sound barrier. Question everything, before you send in the head and after they are done with it.

[crimsondragon]

Here is a followup after I tore down the head. First thing I did was check the torque on all the cam caps as well as the oil pressure regulator. Except for one of bolts on the caps, everything seemed to be in spec. It seemed they used loctite on some of the bolts, which the manual doesn't call for. All the rockers, cams, and caps were fully lubricated and clean.

Another check is did is to see how well the valves are seated against the valve seat. I installed old spark plugs and torqued it to 18 ft*lbs. I turned it upside down and filled each bowl with ATF. I used ATF because I have a shit ton of it. Engine oil would work. I suppose water would too but I used ATF for it's bright red color. Anyway, after 10 minutes I checked each runner. Some of the valves you can see where the ATF is starting to show. Others have dripped and ran down the runners. Two or three are actually sealed very well. #1 and #2 runners are the worst on the intake side as well as #1 on the exhaust side (not as bad as the intake side) as they have ATF flowing.

Those two cylinders concern me and I shall be disassembling the valve assemblies for further investigation. It's either there's some trapped debris between the seat and valve or they did not lap it correctly.

It has also come to my attention from other people that they do in fact just take your head and/or block and throw it on the core shelf. That's very disheartening to say the least. Just a heads up if you want to keep your original engine.

Enjoy the pics!


*edit* Alright one more for the record books. I started removing the lifters after I posted this to check the holes. Turns out some of the lifters were not properly bleed. And when I did bleed them, engine oil came out. I checked the lifter holes. All of them had used oil in it with some nasty dirt and such. One even had the chocolate milk look to it. This head looks good from 5 feet away but once you start tearing into it and doing checks, the ugly shows.

*edit again* Just wanted to clarify something. The test I did to see how well the valves seal is NOT a surefire way of testing them. It's a preliminary test just to see how well they can seal unpressurized. For all I know, if the cylinder was actually pressurized, it might seal very well. Some of them don't leak, so you know they will seal. As for the ones that leak, it might be a slow enough leak to be pressurized and will seat correctly. If I have time, I might actually do a pressurized test. I'll have to figure something out as my 7 bolt has no pistons.

[crimsondragon]

I just got a call back from a local machine shop. I dropped my head off earlier last week to have the valves reseated. They told me none of the valves were seated to the head. Yes you read that correctly. SIM, a race shop, did not bother to seat my new valves to the head. Buyer beware. I officially take back my rating of them and drop it to 3/10.

[BogusSVO]

Dragon, what do you call seated? do you mean lapped in?

Depending on the wquipment used, lapping is not needed.

As far as your pics go, the ones shoung the alum hanging over in the combustion chamber is likley caused by the surfacer equipment.

A Vacuume test should have been pulled on the runner side to check valve seal, and should be 27 in or better to considered sealed.

[crimsondragon]

What I mean by reseating is the valve and seat needed to be ground together.

[BogusSVO]

If good equipment is being used then that does not need to be done.

This is lapping

How to lap a valve

If you look at the valve on the left, that is a fresh ground valve
Why to have your Valves back cut

Well I forgot about this.... Look thu it and you see how I do it...

How to Have a 4G63 head rebuilt.