I have a burnt valve and am having to get the head rebuilt. Since I am doing this anyway, I was thinking about some kind of a performance upgrade. I don't know what to do. Does porting or polishing help?
Any advice would be appreciated.

 

P&P head has proved to be one of the best upgrades to the S over the years. It has been called the Tritec engine's "bottleneck," the secret to unleashing the potential if you will. So...go for it!!!!

 

^^ - 100% agree

Send it over to Mike (Thumper). He'll transform ure car into a beastie!!!

 

Port/ throat/bowl work coupled to a performance valve job.. will allow a lot of power!! Usually between 25-35 WHP on an un-tuned MCS!! And that is keeping the stock valve size.. ( alot depends on the man with the die grinder..lol) You will maintain the low to mid range and the power will just keep on climbing till you red line!! cool??

Have fun and go for it!!

Just me............................

Thumper

 

I wish! My ported /polished head didn't yeld a third of that

 

Who did the polish n port work on ure head?

 

Endyn does outstanding head work, I experienced a 59hp/42lb-ft torque gain over stock with an Endyn mid-size valve ported head and 19% pulley on a 101F day.

 

Endyn really does super nice work, and they have a ton of experience to back that up

 

Thanx for all the input. You all confirmed what I was thinking. I'll talk to my guy and see what we can do with local talent here in the great white north.

 

The head is off and no burnt valve and the head gasket is OK. Waiting for the machine shop to let me know what they find.

 

if it was a compression or leak down test then the valve guide could be binding, but more likely you're looking at a piston ring problem. That would suck.....

Anyway, the tritec can really be opened up with good head work. I'd up the exhaust valve size if you're goint to the trouble. It's not the first engine that has too small exhaust valves...

Matt

 

Compressoin down to 105 psi in #2 cylinder. Leak down test showed no pressure in the crank case.

 

OK.. the head was checked and freshened up.. yes?? Put back on.. and now you have 102 psi in one cylinder?? Do a wet test.. see if the compression comes back up.. Indicating rings!! Befor the Head came off all these tests should have been done by you or the shop.. you CAN have a bad ring and NOT see it with the head off.. go and WATCH the shop and have them explain what they are doing... cool?? Bummer..

Just me........................

Thumper

 

bent valve, burnt valve or valve seat.
head gasket.
rings.
hole in piston.

there is no where else for it to go.

Matt

 

Head hasn't come back from the machine shop yet, maybe on Monday. Promises, promises. Still waiting for the machine shop to bench test the head. It looks OK to the naked eye. We're not putting it back together until we find the root cause of the low compression. My guy here is an ex MINI mechanic. He has all the right answers to all of my questions. I have full confidence in him. I'll keep everyone posted. Thanx again

 

Is the oil still in the engine? Have you dropped coolant in the block during head removal ? If not, have oil analyzed. It will tell you every thing you want to know as far as rings, head gasket, valves etc.

 

I have not thought of having the oil analyzed. thanks a bunch.

 

you'r welcome!
It is usualy not the first thing anybody would think of doing.
Any resolution yet?

 

Finally got the head back from the machine shop. The valve seat on one of the exhaust valves was grooved from excessive temperature and the exhaust valve seating surface was cupped. We think that it could possibly be from a piece of carbon that was stuck between the valve and the seat. My guy has been away until next week. The head has been rebuilt (Valve grind, seats, seals etc.) Still don't know the root cause. Maybe is just bad luck. Going to take our time putting it back together. Don't want to be in the same boat next year. I'll let you know when we are up and running, hopefully next Thursday or Friday as the Great Pumpkin run is on that weekend with the Club.

 

. I still would analyze the oil just to confirm your suspicion.