EJ25 Cylinder Head Bolt Replacement Qs

[walczyk]

Hi everyone, I'm rebuilding an EJ25 (we decided to go the whole nine yards after noticing how gunked our 2000 Legacy's engine was when we were replacing the head gaskets), and I have been trying very hard to choose the best hardware for the job. I know thermal expansion is hard on aluminum heads, and therefore the head bolts so they should be replaced. However, I bought Fel-Pro because those were in stock and now I'm not so sure. Does anyone know hte price for a set of OEM head bolts? I checked out the head studs by cosworth, http://www.cosworthusa.com/store/pc/viewPrd.asp?idproduct=38 but they're $500 ha. I think these studs would absolutely solve the gasket problem but cost wayyy too much. One other thing, I bought an engine gasket set by Ishino something, and its made in japan I think, it cost $230 but I don't know if its OEM. I thought it would be cause it was japanese, but now I am thinking if its worth returning and ordering OEM from subaru. Finally, has anyone here replaced EJ25 bearings and piston rings? Again, OEM is expensive and surprisingly the piston ring set are the most expensive vs the rod bearing set and main bearing set. Any recommendation if i was going to go non-oem? I could buy Cosworth for a slightly reduced price, but I'm not sure, I think if the piston rings are that expensive there msut be something fancy about them.

[GeneralDisorder]

No one (including the dealer) replaces EJ head bolts. Unless they are damaged in some way they can be reused indefinitely. They are not torque-to-yeild and despite what some parts counter guy will tell you they never require replacement.

 

You don't need studs to "fix" the head gaskets on the EJ251 - the gaskets were at fault not the engine design. The sealant used on the gasket suface washed away over time and cause external seepage. The replacement OEM gaskets solve this problem and you should NOT use anything but the dealer part.

 

I have done bearings and rings - I would reccomend ACL for bearings. OEM on rings.

 

GD

Edited March 23, 2011 by GeneralDisorder

[davebugs]

No new head bolts are needed.

 

Some may show a little rust.

 

And it you thought they "creaked" a bit on removal just wait until you reinstall them.

 

Unless you're doing some kind of major performance build new head bolts are just wasted money.

 

If you go to a parts place that sells Felpro head kits - guess what they'll sell you? A Felpro head kit! On Saturns they had a kit that was mostly a couple of tubes of Permatex and the Orings for the spark plug holes. It's what they have to sell you, not what you need. Or at the best quality/price.

[mellow65]

No one (including the dealer) replaces EJ head bolts. Unless they are damaged in some way they can be reused indefinitely. They are not torque-to-yeild and despite what some parts counter guy will tell you they never require replacement.

 

You don't need studs to "fix" the head gaskets on the EJ251 - the gaskets were at fault not the engine design. The sealant used on the gasket suface washed away over time and cause external seepage. The replacement OEM gaskets solve this problem and you should NOT use anything but the dealer part.

 

GD

 

dude what are you talking about, yes they are torque to yield, anytime in the directions you take a bolt to certain torque and then it has you turn it a full 180 degrees past that, that is you stretching the bolts.

 

that being said i have reused head bolts, it's do able, and maybe it wont ever give you a problem, but maybe it will.

 

but just stick with OEM head gaskets, and maybe if you feel like it bolts. Shouldn't run you more then $250 ish from the dealer ship.

 

2nd to that, but 1st in my book, set of ARP head studs and cometic head gaskets. When I did my last motor and this combo cost just a little less then the factory stuff. I ran that in my rally car and beat the snot out of it, never had an issue ever. And it's still plugging away.

[johnceggleston]

dude what are you talking about, yes they are torque to yield, anytime in the directions you take a bolt to certain torque and then it has you turn it a full 180 degrees past that, that is you stretching the bolts.

 

 

at the bottom is the torquing specs info from the 1997 subaru FSM for DOHC engines.

 

two things of note:

1. no where does it mention using new bolts, just new gaskets.

2. the max torque applied to the bolts is 51 ft lbs, which is then released by a 180 degree rotation, twice. the next torquing is to 25 ft lbs in the center and 11 ft lbs in the corners. then a 90 degree tightening for all bolts in sequence, twice.

 

THERE IS NO WAY 51 FT LBS or 25 ft lbs plus a 90 degree turn, twice, much less 11 ft lbs plus 90 degrees twice stretches the bolt to its yielding point.

 

as i understand it this process which is similar to torque-to-yeild but is not really TTY, is designed to pre-load or pre-stress the gasket. but what do i know.

 

(by the way, there has been more than one backyard mechanic that has torqued the head bolts to 132 ft lbs because they mis-read the haynes manual where it said 132 INCH lbs, which is 11 ft lbs.)

 

 

from the 1997 FSM (section 2-3b, page 45).

E: INSTALLATION

1. CYLINDER HEAD

(1) Install cylinder head and gaskets on cylinder block.

CAUTION:

Use new cylinder head gaskets.

 

2) Tighten cylinder head bolts.

(1) Apply a coat of engine oil to washers and bolt

threads.

(2) Tighten all bolts to 29 N⋅m (3.0 kg-m, 22 ft-lb) in

numerical sequence.

Then tighten all bolts to 69 N⋅m (7.0 kg-m, 51 ft-lb) in

numerical sequence.

(3) Back off all bolts by 180° first; back them off by 180°

again.

(4) Tighten bolts 1 and 2 to 34 N⋅m (3.5 kg-m, 25 ftlb).

(5) Tighten bolts 3 , 4 , 5 and 6 to 15 N⋅m (1.5 kg-m,

11 ft-lb).

(6) Tighten all bolts by 80 to 90° in numerical

sequence.

CAUTION:

Do not tighten bolts more than 90°.

(7) Further tighten all bolts by 80 to 90° in numerical

sequence.

CAUTION:

Ensure that the total “re-tightening angle” [steps (6)

and (7) above] do not exceed 180°.

[ShawnW]

I am subaru certified and passed the engine exam with a perfect score.

 

The bolts ARE ok to reuse. They are stretch bolts but its not a worry. Make sure you oil the threads before reinstalling and clean the threads in a parts washer and then with a brass wheel before re-using them.

 

Factory head gaskets, thermostat and gasket, and intake manifold gaskets. The rest you could probably get away with. I don't try because I have a dealer wholesale account and my pricing is very similar to aftermarket most of the time. There is something rather beautiful about a box of parts ordered by vin number that are way more often the right part than any parts store. They still get a part here or there wrong but not very often.

 

I can order you parts if you don't have a dealer that is helpful.

[walczyk]

Thanks for all the great replies, everyone really knows this repair well. Does anyone know the price for OEM head bolts? This is a phase II 2.5 SOHC and has 200k miles before the head gaskets blew, although they had been leaking since we bought it (170k) miles so I don't know if they were ever replaced. I believe the head gaskets are OEM, they are ishino brand and I purchased them from partsgeek which stated they were OEM (they were certainly OEM prices) so I am going to use them. I found OEM piston rings and bearings on subarupartsforyou, but they are rather pricy ($165 for the piston ring set, $149 for main bearing set, and $128 for rod bearing set). Would anyone be able to tell if these piston rings on ebay are OEM? They are listed as made by NPR which is japanese and are around $50, http://cgi.ebay.com/ebaymotors/00-06-2-5L-Subaru-Legacy-EJ25-SOHC-NPR-Piston-Rings-_W0QQcmdZViewItemQQhashZitem3caa87fc28QQitemZ260559076392QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories#ht_3355wt_819

 

Other than these parts, I guess I am mostly worried about proper torquing which is why I'd like to get studs but I haven't been able to find anything in my price range (cosworth is $500). Thanks for all the help everyone, I'll be splitting the block once we figure out how to make a tool to take the pins out (any tips here would be appreciated). I will take pictures soon, thanks again!

 

edit: I've just taken oil separator plate and it looks like a ball bearing has been pressed into a hole right next to the service hole plug. Does anyone know what this does? I was speculating maybe it blows out in case of reallllly high pressure. Or maybe it was just a cheap way to plug a hole. I'm just curious cause its funny looking.

Edited March 23, 2011 by walczyk

[WoodsWagon]

The head bolts end up right around 90ftlbs when you follow the tightening instructions. I did the degree turns using my digital torque wrench, and they all tighten about the same on the final quarter turn.

[GeneralDisorder]

dude what are you talking about, yes they are torque to yield, anytime in the directions you take a bolt to certain torque and then it has you turn it a full 180 degrees past that, that is you stretching the bolts.

 

First off - all bolts stretch to some degree. There is a BIG difference between stress and yield.... in metalurgical terms the stress at which the material starts to exhibit permanent deformation is called yield. Subaru head bolts do stretch but they DO NOT exprience permanent deformation - thus can be reused an indefinite number of times.

 

The reason for the degree turns is purely one of practicality - because the Subaru head bolts tend to creak in a large percentage of cases even when the threads are properly chased and the bolts are clean and lubed - the degree turns are set to put about 90 ft/lbs on the bolts. The creaking will throw off a regular torque insturment. Degree turns are impervious to creaking.

 

So no - Subaru head bolts are NOT torque-to-yield.

 

GD