Did compression test, bent valves?? idk.

[12sec92Tsi]

Well today I decided to check the compression on my motor before spending any more huge amounts of money on upgrades. The results were not good, 140-145-50-150. Awhile back my t-belt jumped 2 or 3 teeth but only ran like that for like 1 minute before I parked it and fixed it the next day. Then I noticed a vibration I did not have before like the bs is out of phase. All the timing marks were lined up. So I'm thinking running it like that for those couple minutes could have bent some valves?? The motor is only like 15-20k miles old since it was completely rebuilt, so the rings should be fine, don't know why they'd be messed up, plus I have a normal 25 psi oil pressure and it's not burning any between oil changes. Another theory I had was the head gasket because I'm only getting like 12 in hg of vacuum at idle and 15 on decel. What do you guys think. Should I just pull the head and replace the head gasket and valves all in one shot and try to fix everything?? I was thinking just pull the head and put on the following things:

Cometic head gasket
ARP head studs
SS oversize valves
Titanium springs and retainers

Also what else should I replace in the valvetrain while in there. Valve guides, seals, etc.?? I'm just really disappointed this happened less than a year since I've had the car on a fresh motor. Just let me know what you guys think the problem is and what I shoud replace while the head is off. Thanks alot.

 

[1fast97gsx]

I'm leaning towards a headgasket problem. Either way the head will have to come off so you might as well get to work

 

[BUCK]

Jerk the Head & have it checked out - NO way would I want ANY of: Cometic head gasket
ARP head studs - SS oversize valves -Titanium springs and retainers.

 

[12sec92Tsi]

Jerk the Head & have it checked out - NO way would I want ANY of: Cometic head gasket
ARP head studs - SS oversize valves -Titanium springs and retainers.

Are the oversize valves and titanium springs and reatainers bad to use on stock cams or something? I thought I heard that somewhere. Should I just use all OEM parts?

 

[BUCK]

Cometics leak, very common on the Boards, When you pull the Head you'll be GLAD you don't have Studs to lift the Head over, & yes IMO there's no need to rap these things out to make HP so why Titanium & the Stock Head flows well so why SS Valves ? Stick with Stock in these areas IMO.

 

[1fast97gsx]

You need really aggresive cams and high rpms to make use of those parts. The arps are a good buy but the rest is overkill from looking at your other mods imo.

 

[12sec92Tsi]

Ok so I'll replace the head gasket, head bolts, and valves with all oem parts. Anything else valve related that should be changed when doing valves?? And should the head be resurfaced before being reinstalled? Thanks for all your help.

 

[1fast97gsx]

You'd need to have the shop that will do your headwork check for warpage and go from there. I personally would keep the arps on there as well as the springs and retainers since you already have them.

 

[12sec92Tsi]

You'd need to have the shop that will do your headwork check for warpage and go from there. I personally would keep the arps on there as well as the springs and retainers since you already have them.

I don't have any of those parts that I listed on the car now, that's just what I was thinking about buying since I'm replacing those parts anyways. But I'm going to stick with the stock or maybee mitsu 4 layer head gasket, arp head studs since I run around 22 psi at the track, and stock valves, springs, retainers, etc. I just want to get this motor back to 100% before upgrading anything else. The shop manual says that the valve guides, valve stem seals, and valve seats are all non reuseable parts, so I guess I have to buy all those things if I'm changing valves?? But I'm just going to take the head to a local machine shop and tell them to check the whole thing over for cracks, leaks, etc., and resurface it if it is warped any, then just install all my new parts and hope that brings the compression back up to where it should be.

 

[1fast97gsx]

sometimes seats and guides need to be replaced and in some cases they can just be cut. If you only plan to fix what's broken you'd almost be cheaper to buy another used dsm head and just slap it on. If you want to rework the whole head ( which you should do since it's coming off ) then it'll be a little more expensive. Either way don't 1/2 ass it now and have more problems later.

 

[12sec92Tsi]

Well today I was talking to my dad about what I should do about this, who was the one that held the pedal to the floor and cranked it while I watched the compression, and he brought up that he did not have the pedal the whole way to the floor. So I do another test today by myself and zip tied the throttle plate the whole way open while I cranked it and then got out quickly to check the gauge. Boy was I releived with the results, 150 across all four. So I guess my motor is good to go after all and now I get to buy a front mount instead of a head rebuild. So thanks anyways for all you guys advice, and sorry to post about a problem that turns our to be nothing. But it makes me feel much better now that I know I have a good motor to continue to mod.