[Volksaholic]

I'm replacing the head gaskets on a 2001 Forester EJ25 (SOHC). I don't see where the factory manual says I should use new head bolts, but maybe that's just something that real mechanics know about modern engines. I've read that because the bolts are designed to stretch that they should always be replaced with new but it seems like most of what I read implies that people are reusing the existing bolts.

What's the risk of reusing these bolts? I'm a proponent of replacing parts that might fail or cause a failure due to wear or stress, but I don't have big cash reserves for unnecessary expenditures on this project.

By the way, this Forester engine is going into a 1988 VW Vanagon to be used for camping, towing small sailboats, light off road, but not racing and hard acceleration, if that makes a difference.

Thanks in advance for your advice.

 

[TC2000]

As you've read many reuse them, the choice is yours. For what they cost though, I think id just replace them.

 

[flstffxe]

As you said the factory manual doesn't specify to replace them. Subaru does however specify in the manual to replace every other bolt that is torque to yield.

As TC2000 said the choice is yours. The risk of reusing them? Doing HG again......

 

[Volksaholic]

Thanks for the quick feedback. I've seen prices for sets of bolts and washer from about $50 to $120 for what appear to be the non-hi performance bolts. What should I expect to pay for decent quality? RockAuto has Fel-Pro for about $51 or RockAuto brand for $116. For something that's OEM spec, what should I expect to pay?

Paul in SLC
2008 Forester
2003 Outback
1988 Vanagon... soon to be Subie powered

 

[huck_this]

Don't need too. Dealer told me so!!!:icon_wink: Just remember to use 30 wt. oil on the threads and bolt head and washer.

 

[Volksaholic]

Yeah... I thought the oil and torquing pattern was interesting. I've built more air cooled VW engines than anything else (those and a Ford 289), so no oil and torquing bolts was all pretty old-school. I appreciate the input about the dealer, but I'm not convinced that the dealers know a helluva lot more than I do, and sometimes less. The dealership I bought my Outback from had a shop staffed with morons, the one we bought my wife's Forester from is about 250% better.

Paul in SLC
2008 Forester
2003 Outback
1988 Vanagon... soon to be Subie powered

 

[Volksaholic]

So the question still stands: Is there a difference in quality or a "preferred" set of head bolts to buy? I've got the Fel-Pro bolts sitting in my online shopping cart because the price is good. I can't justify the cost of (nor do I think I need) racing head bolts at $200, but I'm seeing some OEM bolts for about 2x the price of the Fel-Pro. I don't have money to waste, but it's not cost effective to cheap out now if the Fel-Pro bolts are not reliable.

BTW: I did some more reading online, and I now understand enough that I agree with those who recommend replacing the head bolts. Here's one article that helped convince me, for those who want to understand the problem better: OOPS! The forum software isn't going to let me post the URL. Search enginebuilder.com threaded_fasteners_torquetoyield_and_torquetoangle and it should get you there.

A second, somewhat off topic question is what's the best way to remove carbon deposits from the tops of the pistons. I'm pleased to say that when I got the heads pulled the valves looked wonderful... I don't plan on cleaning them at all. There were slight deposits on the head casting and more on the pistons but for the most part the combustion chamber is a thing of beauty! :icon_biggrin:

Thanks for your advice!

Paul in SLC
2008 Forester
2003 Outback
1988 Vanagon... soon to be Subie powered

 

[flstffxe]

Scotchbrite works well.

 

[Volksaholic]

Thanks for the suggestion... I'll hit them with a Scotch Bright pad. No opinions or experience with aftermarket head bolts? I guess I'll order the Fel-Pro so I can keep the project moving forward.

 

[flstffxe]

Personally I have never used the Fel-Pros. Honestly it would not surprise me if they were OEMs just repackaged. Every time I have replaced them I have used OEM bolts as my dealer gives me a fair price on them, about $65 for the set.

OEM head bolt numbers(1999-2009 NA(SOHC) applications):
11095AA123 Outside bolts with the small washers QTY needed "8"
11095AA141 Inside bolts with the large washer QTY needed "4"

I wouldn't hesitate to order the Fel-Pros.

EDIT:
I see the Fel-Pros are $62 at autozone. Part Number: ES72212

 

[Volksaholic]

Thanks... I appreciate the input. I don't get any discount from my dealer... having 2-1/2 Subarus doesn't get me any special favors! They wanted about $11 per bolt/washer, which is in line with the "OEM" bolts I'm finding online. I ordered the Fel-Pro set.

Paul

 

[westwind999]

The used bolt issue is related to how the bolt stretches in use. When you torque the bolt you are really trying to get a clamping force holding the head tight to the block. If some bolts have stretched more than others the amount of clamping each bolt gives will be a bit different. You should get a more even clamp load on the head using new bolts.

Having said that, I've reused bolts on a beater and drove it for a couple years afterwards with no issues. I guess, as mentioned, it depends on how you feel about doing it again.

 

[Volksaholic]

After reading the article I gave keywords for above, the whole torque procedure made more sense. According to the author, Torque To Yield actually takes special equipment, but Torque To Angle allows you to predictably apply a clamping force based on advancing the bolt a certain number of threads beyond a given torque. The low starting torque coupled with oiled threads and washers means that you're not fighting friction so the starting torque should be accurate.*

I've built a Ford 289, a number of Type I VW engines, and a Type IV VW engine. I think the Ford engineers figured you're clamping an iron head to an iron block so you just apply a s***load of torque and call it a day. The VW engines were low compression and air cooled, so you didn't have to worry about blowing the head off or leaking combustion gases into the water jacket. Back in those days engines were higher maintenance and weren't expected to last as long as we expect today; a VW engine would be getting a rebuild at about 1/2 the minimum life we expect from a modern Subaru, Honda, or Toyota. I haven't done any major engine work for about 10 years, though, so I feel like a bit of a newbie.

Based on what I read... keeping in mind I didn't taken a fastener engineering course... I suspect reusing the head bolts one time would probably be okay, but for the price of the bolts it's cheap insurance if the engine goes 100k or more miles on this head gasket replacement. I appreciate the nudges in the right direction!

Paul in SLC
2008 Forester
2003 Outback
1988 Vanagon... soon to be Subie powered

*That synopsis is for the benefit of those who are trying to understand the rationale for replacing the bolts. There's more in the article, including what a bolt's "yield" is and how it behaves once you've reached or surpassed that yield.