Question about head work Options

[anthony]

My second 914 is a project car runs great but it's annoyingly smokey - like if it had to pass smog I'd guess that there's no way that it would. It puts out noticeable amounts of smoke at idle and gives the visible poof on downshifts.

Well, everybody told me that it was due to worn valve guides. Would it be advisable to pull the heads and have new ones put in? Is this even feasable or do you have to go all out and have a valve job too?

[Dave Cawdrey]

Got to pull em, but the motor has to come out as well. Once off, rebuild 'em. If you think your car runs great now, check out what a top end rebuild would feel like... Proper (IMG:style_emoticons/default/cool_shades.gif)

[Brad Roberts]

What engine is in it Anthony ?? Is this the 5 lug car ?

Our rebuild place kicks ass when it comes to air cooled heads (same place does our race heads does our street heads also) It runs about 400$ if everything has to be done to them.

You may want to do P+C's or at least have your current ones checked out.


B

[meursault]

Well, yeah, you've got to pull the heads to replace the valve guides. If your valve guides are worn, then the valves and seats are going to be worn too. Basically, the valve guides have gone oblong so the valve starts to seat itself in different places.

Yes, you'll need a valve job. the guides are replaced by drilling them out. Heat up the head, freeze the guides, air hammer the cold, contracted guides into the hot, expanded heads, and hone the guides. Then grind the seats and valves and lap them.

You might need to resurface the heads as well. Blackened areas on the head where the cylinder is supposed to seal up to it will tell you if this work is needed as well.

Obviously, a competent machine shop needs to do this work. They might also alert you to other problems with your heads once they're off the motor, like oh, cracking by the spark plugs. All this work obviously needs to be done while you've got the heads off the motor. No way around it. You'll be pretty miserable if you don't do some of the work and try to reassemble the motor after just replacing the valve guides; the smoking may go away, but you won't have the compression numbers you want, and so forth.

While you're at it, you may just want to hone the cylinders and re-ring the pistons. If you have to resurface the head, you might have to pull the cylinders to add shims anyway....

Hope this isn't too much doom and gloom. Good luck.

[MarkV]

I would be leery of the hone & re-ring routine. I did that and now I am going to have to take it apart again. My car smokes like I am running it on mesquite. (IMG:style_emoticons/default/pain30.gif)

[Brad Roberts]

Mark,

did you buy over sized rings and gap them correctly ?? Did the cylinder bores mic' within spec ??

Whoes rings did you use ??


B

[MarkV]

Brad,

I bought the car w/ the fresh engine in it. The seller is a mechanic and has a local Porsche garage. He bought the car w/ a blown engine. I have an invoice w/ all the parts that went into it. I think they are standard size rings. He claims that they are chrome Deves rings and that they may still seat.

He has a good reputation and didn't go cheap on the rest of the parts. Line bored the block, used new sodium ex valves.

Can't really go back on him. I bought the car in 95 and it has been in my garage w/ a cover on it. The engine has 5,000 miles on it but most of that has been in the last couple of years. (IMG:style_emoticons/default/smash.gif)

[Brad Roberts]

Thanks. I almost asked in the last post if it had Chrome rings in it. I have seen some NEVER seat and others that have seated within 10 minutes of startup.

I dont have any secrets to help them seat for you...

B

[J P Stein]

MarkV:

It may be too late, but........*non detergent oil*...particularly true for chrome moly rings. Give it a try for 200 miles or so. I use it exclusivly for new rings and it's never failed me. My 2.7s rings were seated in less than 100 miles even with used Nikasil cyls (iron rings, tho).....but then, get it the hell outta there.

If that don't work.....there's a "last chance" with Bon Ami. Nuthin to loose at that point.

[Gint]

If that don't work.....there's a "last chance" with Bon Ami. Nuthin to loose at that point.

Ahh. The old 55 Chevy 265 V8 trick. We were telling some of the less car oriented folk at work about this the other day. Question: If you end up resorting to such a thing, what would the procedure be? How much do you put in? Where? How? How long do you run it like that, etc...

[seanery]

JP,

My mechanic swears by the "non detergent oil" for engine breakin. I wondered why, now I know!

[Bleyseng]

Using non-detergent 30wt oil has always worked for me too. Been using that method for 35 years, geez its been that long! I don't remember the Bon Ami for 55 Chebby rings only for bath tub rings, JP.
Geoff

[JWest]

Where do you find (buy) non-detergent oil? I seem to remember not being able to find it last time I looked.

[Gint]

I don't remember the Bon Ami for 55 Chebby rings only for bath tub rings, JP.

JP was probably there. (IMG:style_emoticons/default/laugh.gif) When Chevrolet introduced the 265 V8, the rings wouldn't seat properly and they were having dealers put Bonami in them to roughen up the cylinder walls. I don't know any more detail than that. I'm curious about it though and was hoping some of the, ah, more seasoned members might be able to enlighten me (us).

[seanery]

I found it at NAPA. I had to go to 2 or 3 stores to get enough for a 6, though.

[Mark Henry]

Where do you find (buy) non-detergent oil? I seem to remember not being able to find it last time I looked.

Valvoline has ND oil, may/will be special order at your FLAPS. Also air compressors use ND oil.

[anthony]

Brad, this is the '74 2L 5 lug white car I bought:

http://www.well.com/user/anthony/914/white/

You say only $400 for headwork? Sounds like a bargain. That must be per head.

I'll probably sell this car before I tear into the engine but I was wondering what was involved and what the possibilities are.

[MarkV]

Thanks guys,

I tried the non-detergent oil. Made for some extra smoke but didn't seem to help the rings any.

Heard about the Bon-Ami trick from an old-timer Alpha Romeo mechanic. I bought some and tried a little. It made a mess out of my engine compartment & plugged one of my idle jets. I don't want to ruin the valve guides or wash out the bearings.

I am going to replace the P&C's and be done w/ it.

[Brad Roberts]

Anthony,

It really depends on how bad the heads are. 400$ is a set of heads that didnt need valves but needed springs/guides/valve job and crack repair on 2 spark plug holes.

Is this a 2.0 engine ??


B

[Bleyseng]

That seems to be the going rate. Porting, new valves are extra of course.
Geoff