valve adjustment screws

[mark]

Hi Guys:

OK I am well into my valve adjustment process. I have about 7000 miles on the current set of screws. The intake screws are barely worn, except for one which had tightened up. The exhaust screws are another matter. They all appear to need replacement, and in fact two of them started to spall on the edge, Yikes.

1. Is it normal to have this much wear in 7000 miles? 2. Anything I should do differently? The manual as well as the Riff/Roush tuning tips say that the clearances should be 20 and 25 intake and exhaust respectively. That's where I put em.

Any insight would be appreciated.

Mark

P.S. I checked the cam timing by the flywheel method, just to see what is what. It appears that the timing is advanced about 4-5 teeth. Seems odd since the bloody timing chain is usually guilty of causing retardation.

[250GT]

Mark,
The adjuster screws are made to wear. The valve stems are hardened so they don't should show wear, the adjusters are softer and made to be adjusted.
Every 10K km(7000 miles) is VERY much imo, that means every valve check new screws !
My conversion shows no wear at all after 103K km . but cost about 1600 euro, rollers and screws kit ,
How much is that every km?
My clearance is only 10. and 15. and gives a lower noise level.

Very nice Quatation T.Y. at Art Taxman article:

" We all agreed spending the afternoon crawling around old dusty cars was way more fun than going to the shows for the last few days!"

C.

[tyang]

Hi Mark,

More importantly, what do the top of the exhaust valve look like? If they show no marks, then the adjusters did what they were supposed to do. Having a baseline for wear, I would be checking valve lash at 7k miles, maybe 6K.

As for valve timing,
Just for kicks, I would check intake timing on cylinder #6. It comes up 360 degrees after #1 TDC on compression stroke, PM1/6. I'd be curious to see how far off the marks are for #6. Cams twist.

Tom

[250GT]

I wrote something confusion
" Every 10K km(7000 miles) is VERY much imo, that means every valve check new screws !"
What I mean to say and was an answer for question 1.
So much wear after 7000k is FAR TO MUCH.
Probebly also this bad production stuff.
checking Clearance after 7000k miles is normal.
Some people(me) are thinking differant or too fast, sorry

C.

[mark]

Thanks Guys.

Yes, I suspect poor materials for the screws, glad I caught it. I just received some replacements from one of the usual suspects,
they have a different appearance. I will use them for the exhaust side and see what happens. The intakes were barely worn, so I have at least another service from them.

I will also remove at least one of the roller/rocker assemblies to check on the condition of the valve stem and also check the roller assembly for wear. The 7/12 cam timing will be reviewed as per Tom's suggestion.

Finally, what about the cam/chain covers? I have heard some reports that painting the inside of the covers with Glyptal is a good idea. Not sure i agree with this, but would like to hear from the brain trust.

cheers

Mark

[tyang]

I wrote something confusion
" Every 10K km(7000 miles) is VERY much imo, that means every valve check new screws !"
What I mean to say and was an answer for question 1.
So much wear after 7000k is FAR TO MUCH.
Probebly also this bad production stuff.
checking Clearance after 7000k miles is normal.
Some people(me) are thinking differant or too fast, sorry

C.

I agree with Cornelis, if those adjusters wore out in 7K miles, it was too fast. If you check them again in 6-7K miles and there isn't the same wear, you got a bad set of adjusters. I don't know how long it will take for you to drive 7K miles, but it would be great to follow up on this situation on this thread!

I would inspect all the tops of the valves since you have the cam covers off. Take good notes so you establish a base line when you do it again in 7K miles. Obviously, this is done one at a time, keeping the cam in place and in tension.

Tom

[DWR46]

As to painting the inside of the cam and chain covers, the factory originally painted them with a greenish-yellow phosphate primer. With age, it turns a brownish-yellow, and that is what you should see on engines with some miles on them. To my knowledge, phosphate primers are no longer available in the U.S. (EPA rules). I would have no problem using glyptal or another high quality internal engine paint. It will seal the metal pores and keep any trash out of the oil system. Just be sure everything is spotlessly clean before you paint. You want to make sure the paint is adhered well to the metal surface.

[mark]

OK, guys, got the cam timing verified, one big question though. The marks on the flywheel are AA 22 and CS 21 or exhaust and intake respectively 0.5mm. I also used a little 6" degree wheel to monitor my progress.

The factory says that the cams should be @ 13 degrees 15 minutes 0.5mm, for both intake and exhaust.
What's up with that? I checked the flywheel for any marks at the 13 degree area, nothing; In fact I documented every factory mark on the flywheel.

The car ran well before this work, and I intend to leave it on the factory settings, but I am curious. my car is a US version, so perhaps?

Cheers

Mark