[backkraker]

Hello to all !!!!! Found no compression in the number 1 cylinder. pulled heads off and found head gasket leaking on number 1 cylinder. I thought it strange that I would have zero compression so I put the all spark plugs in and filled up the combustion chambers with WD40. Head chambers 1 and 4 leaked all fluid out in 1.5 minutes.
I brought the heads to the machine shop where they were dissasembled. I recieved a message from this very reputable machinist/ engine rebuilder, who informed me that I had four bent valves. 2 exhaust 2 intake, chambers 1 and 4. When I dropped the heads off I mentioned that alfa V6's wear the valve guides( via alfaBB) and that I would like all new guides and springs. In his message he stated that all the guides were PERFECT but if I wanted him to replace them he would.
My question is how can the guides be perfect with bent valves?
Is there any tricks about doing the heads? eg. cam seal O-rings that I can tell the machinist about?
How do you think the valves bent in this good running engine, with no marks on the pistons or in the combustion chambers?

I have 5 Milano verde's but this is the first one that I have had done any work on. Any advice would be appreciated

Cheers; Joe

 

[hughqv]

Definitely replace them all. Pulled the heads off the old mans 3.0 this weekend, it was getting pretty smokey. Its looked after the bores nicely though. Just wondering what valve guide seals you guys use. We have the higher temp rated ones to go in, but I thought i read somewhere of someone using Porsche 911 ones? Or am I dreaming....?
Cheers.

 

[scott.venables]

Is it possible this car now has non interference pistons because of the supercharger install or is the motor internally stock?

 

[junglejustice]

Hi Doc Joe - sorry about your troubles... A few questions;

1) Is this on the S/C car?
2) What "point" in running it, (or symptoms - if you will) lead up to "...found no compression in number 1..."? (Looking for the "event" that would have caused the valve to bend and/or the head gasket to go.) - Long idle - got hot? High rev/heavy load run? Parked in gear on a hill? Just woke up one morning and "bam!"...?
3) How many miles since the last rebuild (if ever?)

As far as "tap" marks on the pistons; it is not un-likely to have bent valves and not be able to see the tell-tale dings on the pistons. It doesn't take much.

As far as the guides - been there - change them! Don't take a chance regardless of the miles since they were last done! The machinist might be looking at the "oval" qualities of each guide and still miss a hairline-crack due to the lateral pressure on the guide from a knocked valve! It takes just ONE to have a smoker on your hands after "rebuild" - change them all!

They could do a simple test too; John at Autosport in Seattle (does all of Ferrari of Seattle's rebuild and head work) has a nice simple air-hose setup on a bench. The hose is connected to a rubber pad that he presses up over the combustion chamber (with the valve in) - spray some soapy water around the BASE of the guide (on the top-side of the head) and bubbles quickly show you leaks around the guide - even if there is a leak between the guide and the aluminium of the head!)

Testing the inside of the guide by itself is more tricky - they can run vacuum on it, (but then again - why? Just change them all.)

 

[backkraker]

Thanks to all, this is not the supercharged car, but a car that I picked up in Canada that was a second owner with 130,000 miles (absolutely a beautiful car with a factory veloce body kit)Greg gordon's father said it was the best Milano he had ever seen. I was driving it hard shifting at 6000rpm (safely) and very quickly felt a cylinder drop out. Limped her home about 1.5 miles. Checked compression 000000 at number one . I will post pictures soon Of the car and heads. Thanks for the great advice and have already ordered the guides and springs.

Joe

 

[backkraker]

Any special valve guides I should be using? Type of valve grind?

Joe

 

[hughqv]

Definitely replace them all. Pulled the heads off the old mans 3.0 this weekend, it was getting pretty smokey. Its looked after the bores nicely though. Just wondering what valve guide seals you guys use. We have the higher temp rated ones to go in, but I thought i read somewhere of someone using Porsche 911 ones? Or am I dreaming....?
Cheers.

Okay so we looked into this, the 911 valves are 9mm stems but OD is larger, so would need to be sleeved...

 

[slyalfa]

I think both IAP and centerline have good guides.
the centerline use ther own seals. the IAP will use std. but get the green Viton (DO NOT USE the BLACK IN the HEAD KIT) they are junk and will start to leak right away.
BTW valves at IAP are very cheap intake $14.25 ex $18.95
cheaper then having the local guy redo the old here.

 

[5yearplan]

Look on the bright side, now you don't need an excuse to get a stage 3 port and polish Seriously though, sorry to hear about it, at least you got her home though.

 

[backkraker]

3.0 valve job

Slyalfa, green Viton? Where do I get these?

Joe

 

[junglejustice]

Stick with the German "Goertzie"? valve-stem seals.

 

[slyalfa]

"Slyalfa, green Viton? Where do I get these?"
that is what IAP sell #38002

there web image is black. but in there book it is green.
and I pulled some green off a old head and there were still soft and sealing perfect. very nice