Valve seats

[lord_rootes]

Hi folks,
I recently read somewhere (on this forum plus another source) that aluminum head engines already had hardened valve seats from new so having hardened seats installed is not necessary. In other words unleaded fuel will not harm them like it would in an iron head engine. Is there any truth to this?
My new Series V has 66,000 original miles and seems to be running well with compression of 135 - 140 across all cylinders. I know it has not had a lead additive added to the fuel up to this point in its life but I was planning on starting to do it but now I'm wondering if it is worth it. I suppose it wouldn't hurt to add it but if it's deemed unnecessary I might as well save the money.
As usual, any input is greatly appreciated.
Thanks,
Alan

 

[RootesRacer]

Hi folks,
I recently read somewhere (on this forum plus another source) that aluminum head engines already had hardened valve seats from new so having hardened seats installed is not necessary. In other words unleaded fuel will not harm them like it would in an iron head engine. Is there any truth to this?
My new Series V has 66,000 original miles and seems to be running well with compression of 135 - 140 across all cylinders. I know it has not had a lead additive added to the fuel up to this point in its life but I was planning on starting to do it but now I'm wondering if it is worth it. I suppose it wouldn't hurt to add it but if it's deemed unnecessary I might as well save the money.
As usual, any input is greatly appreciated.
Thanks,
Alan

Its partly true, the alloy head seats are an early hardened alloy, most think it was stellite.
The valves, particularly the exhausts though are not really high quality so there is still valve and seat erosion, just not as much as existed on older iron headed engines from the era.

 

[lord_rootes]

Its partly true, the alloy head seats are an early hardened alloy, most think it was stellite.
The valves, particularly the exhausts though are not really high quality so there is still valve and seat erosion, just not as much as existed on older iron headed engines from the era.

Thanks RootesRacer, I think I might still start adding the additive, couldn't hurt I guess.

 

[alpine_64]

There was a lot of study about vsr on older engines done in the UK back around 2000 when they were withdrawing leader fuel.

One thing that came out of the lead replacement producttests was that different manufacturers used different additives to protect the valves and seats, it was found that mixing additives with different bases caused issues, so if you start using an additive stick to that brand or make sure any other you use has a similar base additive.

As a side note they found vsr generally started above 3000rpm there was little effect bellow that.

 

[lord_rootes]

There was a lot of study about vsr on older engines done in the UK back around 2000 when they were withdrawing leader fuel.

One thing that came out of the lead replacement producttests was that different manufacturers used different additives to protect the valves and seats, it was found that mixing additives with different bases caused issues, so if you start using an additive stick to that brand or make sure any other you use has a similar base additive.

As a side note they found vsr generally started above 3000rpm there was little effect bellow that.

Thanks Michael, that's very good info to have. I still haven't decided what I will do. Part of me says its run this long without any problems so maybe I'll just leave as is.

Alan

 

[RootesRooter]

I've noticed that on the heads I've looked at with valve recession problems, the valves are rarely evenly receded. It's often one glaringly bad seat, two marginal and the fourth one that doesn't look too bad at all. If your compression is pretty even across the cylinders, and you're not having to make unscheduled valve adjustments, I'd say your seats are fine. Now if you decided to take your Alpine on a cross-continent freeway trip next summer, that's a different story...

 

[tony perrett]

We have a saying, "If it's not broken don't fix it". The time to replace the seats would be when you have another reason to work on the head.

 

[lord_rootes]

I've noticed that on the heads I've looked at with valve recession problems, the valves are rarely evenly receded. It's often one glaringly bad seat, two marginal and the fourth one that doesn't look too bad at all. If your compression is pretty even across the cylinders, and you're not having to make unscheduled valve adjustments, I'd say your seats are fine. Now if you decided to take your Alpine on a cross-continent freeway trip next summer, that's a different story...

Well that is something to consider as we do like to do long trips every year in our cars (usually several thousand miles with lots of highway driving). Next year we will be using the Rapier again (it has a rebuilt 1725 with hardened valve seats) but would like to use the Alpine more in the future. I have been tossing around the thought of rebuilding the engine anyways. Part of me says that's stupid as it runs fine but the other part says I'll probably have to do it at some point anyways so....
The other option is to just do the head but I've always felt that it's silly to just redo half of the engine.
Thanks,
Alan

 

[Hodee]

Is there a decent dependable lead additive available over the counter? Don't want to waste my money if the quality is not there.

 

[chazza]

In all my motoring since leaded petrol was discontinued, I have never had a problem with running on ULP and this includes totally unmodified cast-iron engines and aluminium ones.

It also includes sustained high revs on long journeys and my friend with an unmodified Datsun ute has experienced the same thing.

When I worked at an engine re-conditioners, the boss told me that they had seen no valve seat recession but they got heaps of work from people who had converted their engines to LPG.

My opinion is do nothing and save money wasted on additives, for something that really needs fixing,

Cheers Charlie

 

[Tom H]

I've put 16,000 cross country miles on my Alpine , mostly at 70 MPH (3500 RPM with OD and 3.89 axle) and have had no valve recession issues. All the valves and valve seats are original except #4 Intake which burned at high speed, due, I think, to excess temperature and likely pinging. The engine tended to run hot. When I disassembled it I found, as is typical I hear, the #4 cyl had casting sand and crud around that cylinder inside the coolant jacket. I rebuilt the engine with Chevy Rods, Vizard Mod, and had the machine shop repair the head by replacing the one bad exh seat. And I had the radiator re-cored with 3 rows. I've put the 16,000 miles of high speed running on it since that overhaul and no valve recession, and no fuel additive

Tom

 

[Hodee]

Can I assume that high temps are one cause of recession while the other may be high rpm? My recored radiator keeps my engine temps in perfect zone even in Texas heat. What typically causes the recession?

 

[Chuck Ingram]

When they went to no lead Shell ran engines at speed for thousands of miles
No valve problems. We ran stock Alpines from day one and never had a problem
Top tune though was very important