How long for Valves?

larry47us · 03-31-2004, 08:40 PM

I am rebuilding a 73E Targa, and my wrench has the engine out and stripped. He is detailing it and the engine compartment. The engine is sound, and we hadn't planned on doing any engine work.

Yesterday he calls me and says "You know, it has been 65K miles since the last valve job, and I'll bet that you will need valve guides soon. Since I have the engine out, you want me to pull the heads and replace the valve guides and valves?"

I am already over budget on this project, but if I am going to need a top end redo in the next few years, I might as well have him do it. But, friends in Chicago tell me that the top end on a 2.4L engine should last 100K miles. If that is true, then I have maybe 35K miles of driving till I really need one. If I only drive 5K per year, that's 7 years!!! I would wait.

The plugs are heavily carbonned, due to an overrich injector pump, but there is no fouling evident. The leakdown and compression numbers are good - 145 - 150 for compression and 8 - 10% for leakdown. But I can't test out if the guides are sound without pulling the head.

What do you think? Should I go for it, or just wait?

larry

einreb · 04-01-2004, 05:51 AM

Larry,

Wait. By the time you need the top end work you will have tinkered with the car yourself and will be ready to do the top end job on your own. Just doing something because the engine is out could apply to a lot of things

-Bernie

Doug Steinel · Doug Steinel's Garage

Larry,

You can check for signs of worn valve guides.... Does your car emit a puff of smoke when you deaccelerate? If it does it may need guides. Also, remove the valve covers and see if a valve that is not being pushd by a rocker can be wiggled side-to-side. If it can, this is another sign of worn valve guides. I think the heads on the 2.4L have been very durable, anyone with experience in this area?

Superman · 04-01-2004, 09:28 AM

Actually the valves to test-wiggle are the ones that are depressed by a rocker, approximately 10mm. The wear on the valve will be toward the head end, and the thinnest part of the shaft should be just over the end of the guide when it's open about 10mm. When the valve is closed, this looseness cannot be found by wiggling the valve because the valve's head will be against the seat, preventing the shaft from moving laterally, at least at the head end.

The puff of smoke test is good too. Coast down a hill in gear for a bit and when you put your foot on the throttle again, watch your rear view mirror. If opening the throttle causes a puff of oil smoke, you have guide wear.

Wayne 962 · Wayne 962's Garage

65K on valves that have already been done in the past few years is not a lot of miles. Sounds like he's fishing for work. The Ferrari mechanics seem to do this all the time - replace everything even though it's not necessary...

-Wayne

larry47us · 04-01-2004, 09:36 PM

Thanks for the advice, guys. Looks like I will have him do the cosmetic stuff on the engine - pull the valve covers and powder coat them, and clean the rest up, and then . . .button it up and put it back where it belongs.

OK, Bernie, I look forward to your help when it is time to pull the heads and do the valves. Maybe by that time, Jay will be long done with his engine, and you guys will be good teachers for me.

larry