Big inch sbf....valve guide issue?

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Big inch sbf....valve guide issue?

Post  David Cole on May 31st 2013, 5:53 pm

Posting for a friend who is not a member. (He has had bbf's but is back to the sbf at this time)

New build. 454 ci SBF. 9.5" block.

Yates C3 heads, Ex Penske Cup heads, matching intake w spacers for the 9.2 intake on the 9.5 block. All Jesel valve train. On gas with a single Dominator. 1050 on the test stand. 1150 being built right now at a major carb builder.

Engine is on the crank up/test stand to check for leaks, etc. Starts, runs, sounds good. On start up with a cold engine everything is fine. After about 12-15 mins running time when it gets up to operating temp.......Oil starts dripping out of the headers on each side. Some smoke from the hot headers, but it's not like the oil is being burned in the chamber.

Did a compression check and all 8 are very close to 225 psi.

I'm thinking the valve seals on the exhaust side. I've seen the heads before the build but didn't pay much attention to the seals. He says they don't use a conventional seal. They have a valve guide sticking up and it has an O-ring inside the guide that seals on the valve.

Possible these O-rings are bad? Common issue? Where do you source new ones? Seems like the heat on an ex guide would call for a special o-ring? Thoughts?


Last edited by David Cole on May 31st 2013, 5:54 pm; edited 1 time in total
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Re: Big inch sbf....valve guide issue?

Post  David Cole on May 31st 2013, 5:54 pm

nm, double post
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Re: Big inch sbf....valve guide issue?

Post  Wheelie58 on May 31st 2013, 7:07 pm

David,
I recently did a similar all aluminum SBF using some ex-cup heads. They came to me with no exhaust seals, but I installed conventional seals on both intake and exhaust. I have not experienced an internal valve stem seal.
Even with no seals, it would be unusual to have oil running out the exhaust with the engine running.
Some builders secure the guides in those heads with diagonally drilled set screws that are under the valve spring cups. Maybe someone left the set screws out and the oil is sneaking through there?
Also, like the BBFs those Jesel stand bolts poke in to the intake ports. RTV on the bolts?
Strange one for sure.
Keith
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Re: Big inch sbf....valve guide issue?

Post  c.evans on May 31st 2013, 7:39 pm

David,

Just some general comments. Lawes has four Roush Nationwide engines here, and they;
1. Like to use valve spring oilers.
2. Flood the top of the engine so that the valve springs are standing in oil.
3. Require seperate stages on the dry sump in order to remove the top end oil, i.e. the cam tunnel is sealed.

He put oneof those engines in a drag car, and made up seperate return lines to drain the cylinder heads to the oil pan. If I were you run the engine and then immediately pull the valve cover in order to see how much oil is "captured" upstairs. As for that style seal, I am unaware of it. But it sounds like they have failed and need replacing.

Charlie

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Re: Big inch sbf....valve guide issue?

Post  Wheelie58 on May 31st 2013, 7:52 pm

10-4 on those external oil drain backs !
I left that out....
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Re: Big inch sbf....valve guide issue?

Post  LivermoreDave on May 31st 2013, 10:21 pm

David Cole wrote: On start up with a cold engine everything is fine. After about 12-15 mins running time when it gets up to operating temp.......Oil starts dripping out of the headers on each side. Some smoke from the hot headers, but it's not like the oil is being burned in the chamber.

David I'm no mechanic but with oil dripping out of the headers, not much smoke and no fouled spark plugs, something is wrong, seriously wrong! An oil leak of that type should be very noticeable.

Dave.

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Re: Big inch sbf....valve guide issue?

Post  David Cole on June 1st 2013, 2:44 pm

Thanks guys,

Sounds like a combination of needing new seals on the exhaust and checking out the drainback situation.

Charlie, this engine is for Jeff Pound's Maverick. Lawes did the heads that are on the current engine. A 438ci sbf with a set of old C302B heads. This new 454 is set up to be a plug n play replacement for it.
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Re: Big inch sbf....valve guide issue?

Post  maverick on June 1st 2013, 5:39 pm

Does this thing have header evac tubes on it? It seems to me that oil dripping from the headers (not being burned) would have to be introduced into the headers way downstream, otherwise you'd have a lot of accomanying smoke. Just a harebrained thought.
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Re: Big inch sbf....valve guide issue?

Post  QtrWarrior on June 1st 2013, 5:52 pm

If the oil is coming from the exhaust guides, you should be able to look at the exhaust port and see it..
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Re: Big inch sbf....valve guide issue?

Post  cool40 on June 1st 2013, 11:18 pm

I dont have seals on mine and only notice a little oil in the top of the port out a few inches in the header.
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Re: Big inch sbf....valve guide issue?

Post  DanH on June 2nd 2013, 1:56 am

cool40 wrote:I dont have seals on mine and only notice a little oil in the top of the port out a few inches in the header.
X 2 with no seals and very little oil trace,

oil rings , intake gaskes/sealing I'd check.

this build has adapter plates

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update

Post  David Cole on July 8th 2013, 11:56 pm

Update....

Issue seems to be solved.  Was a combination of problems with oil drainback and also the O-ring type seals that were inside the guides.  Had the guides machines for conventional seals.  The guides were an odd metric size like used on some imports according to the machinist.   The oil drain back holes also had restrictors installed from the underside.  Pipe plug with a hole drilled in it.  Installed from the block side of the head.   Just missed them because not used to looking for them.

Anyways, it's back together.  No smoke/oil out the headers.  On the test stand it sounds great.  I think a 454 sbf is pretty cool.  





Going in this car, phone video:
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Re: Big inch sbf....valve guide issue?

Post  torino501 on July 9th 2013, 7:45 am

talk about some morning wood...? a 454 sbf with cup heads will do it...

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Re: Big inch sbf....valve guide issue?

Post  torino501 on July 9th 2013, 7:45 am

what block did you use?

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Re: Big inch sbf....valve guide issue?

Post  David Cole on July 9th 2013, 10:29 am

Dart 9.5" deck
Intake is for a Cup 9.2 so they made spacers and a new valley pan.
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Re: Big inch sbf....valve guide issue?

Post  Dave C. on July 9th 2013, 12:01 pm

Why no exhaust valve guide seals on some engines?

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Re: Big inch sbf....valve guide issue?

Post  kim on July 9th 2013, 6:47 pm

some engines built for alcohol are built without exhaust valve seals, a little oil down the guide keeps em from sticking. The alcohol washes the guide dry, and with the valve expansion because of heat....

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