Rebuild or replace with a new or rebuilt short block? Who has the best deal?

[turbofiat124]

Sorry for the absence guys. I had to work night shift the other night and for some reason my company has blacklisted this forum (bad web reputation or something ignorant).

Anyway. Big thanks to all that have guided me toward looking at the head gasket before replacing the engine.

So I went ahead and ordered a new head gasket Saturday off Ebay. But it has not shown up as being shipped. So I sent the guy a nastygram asking when he plans on sending me my head gasket because I have already pulled the cylinder head off and cleaned up.

So today I was about and about and decided to see if anybody had this gasket locally so I could get this project wrapped up.

Would you believe all three Briggs parts suppliers in my area did not have this gasket in stock! I would have thought the 21HP Intek would have been a common engine. So I guess I'll just have to wait on my head gasket.

Take a look at the serious carbon buildup!

Initially I could not find the break in the gasket facing the cylinder head but after I pulled it off, it appears to have broken in the middle. Of course the break could have been from where I had pulled the gasket off.

[/URL]

Some carburator cleaner, wire brush and some #0000 fine steel 2 hours later:

Motor oil, black as tar!

[/URL]

Homemade valve cover gasket made from GoreTex:

Dumb question but there was these little battery looking things in the tray of my parts washer:

[/URL]

Best I can tell they go on top of the valves. Is that correct?

I printed off the Briggs and Stratton service manual (all 178 pages) at work. HAH!

I painted some reference marks so I know that the engine is 1/4" from TDC before setting the valve clearances. Aluminum push rod= intake, steel = exhaust. 18 ft lbs for the head bolts.

Hopefully I'm good to go once my head gasket arrives.

I probably shouldn't have down this once I noticed it started using oil. I figure I have one more session of mulching and I will be done for the season.

I'm glad I decided to tear it down now because I may have ended up buying a new engine. Based on how black the motor oil was turning just after three hours of use.

 

[Rivets]

First, yes those caps go on the valves, which the rocker arms will hold in place when you set your valve clearances. Second, yes your head gasket was definitely blown. Third, read the manual carefully, have patience, and take your time when reassembling. Finally, nice clean-up job.

 

[bertsmobile1]

If you can pull the two dowels out of the block, glue some 400 to 600 wet & dry to a lump of flat glass and dress both the cylinder joining face and the head.
You will find they both are a little hollow between the cylinder & pushrod tunnel where the gasket blew.
If you can not do the block, make sure you do the head or you will be doing this job all over again a lot sooner than you would have liked too.
No head gaskets i stock is very common , they are a vey fast moving item.
I tyr to have 4 of each of the 4 ride on sizes in stock but rarely ar there more than 2 or 3.
They are a very fast moving item.
For 2 of the sizes there is a Stens aftermarket gasket which is a lot better than the B & S original. I rarely have one of these fail.
Jacks keeps the after market gaskets and I strongly recommend you fitting on.

And praise where it belongs, nice job to date.
Put some gasket cement on the rocker cover to glue the gasket in place an some high temperature grease or nickel anti sieze on the other side so the gasket strips off the engine clean.
Makes checking valve lash much easier and you will need to do it a couple of times till the new gasket settles in.

 

[turbofiat124]

If you can pull the two dowels out of the block, glue some 400 to 600 wet & dry to a lump of flat glass and dress both the cylinder joining face and the head.
You will find they both are a little hollow between the cylinder & pushrod tunnel where the gasket blew.
If you can not do the block, make sure you do the head or you will be doing this job all over again a lot sooner than you would have liked too.
No head gaskets i stock is very common , they are a vey fast moving item.
I tyr to have 4 of each of the 4 ride on sizes in stock but rarely ar there more than 2 or 3.
They are a very fast moving item.
For 2 of the sizes there is a Stens aftermarket gasket which is a lot better than the B & S original. I rarely have one of these fail.
Jacks keeps the after market gaskets and I strongly recommend you fitting on.

And praise where it belongs, nice job to date.
Put some gasket cement on the rocker cover to glue the gasket in place an some high temperature grease or nickel anti sieze on the other side so the gasket strips off the engine clean.
Makes checking valve lash much easier and you will need to do it a couple of times till the new gasket settles in.

Thanks for the advice. That probably wouldn't be a bad idea. You can't see it in the photo but I noticed there was some discoloring (slight purple) on the engine block where the gasket blew. Have you ever seen that?

If you notice the blue stuff on my homemade valve cover gasket I made of GoreTex, it's called Steel Ink which can be used to find low spots in surfaces.

Also notice where there is still some carbon on the piston. It's embedded in some pitting in that area. I wonder the pitting that was caused by some detonation from the carbon buildup? Or is this an imperfection in the casting? There was no pitting on the head.

I've actually done something similar with exhaust flanges on turbos. I used a piece of glass and valve lapping compound to resurface a downpipe flange on a T3 turbo.

The guy I bought the gasket from said his internet was down and sent the gasket out today.

 

[bertsmobile1]

Yes there is always some damage to both he head & barrel.
Mostly on the head.
Depends just how long the owner has been using it like that.
Some I have done would have been using almost as much oil as fuel and more than one neighbour has come out with some advice on what the owner should do with that Bloo? smokey mower.

 

[turbofiat124]

I had a detailed update with photos written out (took me 30 minutes) but now it's gone or I hit preview instead of post. :frown:

I don't feel like retying my post it at the moment but the jest of it is, I resurfaced the head, valves adjusted and it fired right up and no blue smoke.

My main question was concerning the head shield that surrounds the fins on the cylinder head. It's held on by a small bolt with a 5/16" head. Before I removed it (to resurface the block) it seemed stationary but now I can sort of move it around and think it might vibrate or rattle. I'm afraid to tighten it more for fear of braking the bolt off.

Does this shield aid in cooling or is it just a heat shield to prevent thermal burns? in other words if it starts to make a racket, I'd just soon remove it but if it's there to aid to cooling, then why is it moving around? Looks like it should have more than one fastener hold it in place.

 

[bertsmobile1]

It is essential, don't even think about leaving it off.
Clean out the bolt hole and ou might need to run a tap down it to clean up the thread.
The air baffles are not particularly tight and locate onto the top cover,
If it worries you slip a small O ring under the head of the bolt to take up the slack.
Remember it all gets quite hot and there has to be expansion space.

 

[turbofiat124]

It is essential, don't even think about leaving it off.
Clean out the bolt hole and ou might need to run a tap down it to clean up the thread.
The air baffles are not particularly tight and locate onto the top cover,
If it worries you slip a small O ring under the head of the bolt to take up the slack.
Remember it all gets quite hot and there has to be expansion space.

I was thinking the shield clipped onto the engine block somewhere but can't seem to find a location where I might. So does the shield just "dangle" using one bolt?

What I meant earlier but was a lose for words was I can rotate the shield a bit from side to side.

Here is the shield in question:

Notice there is a bend near the starter. It appears this bend should pop in place against the block so to speak. If that make sense.

I thought I might have left a shield off the engine but it is nowhere to be found in my garage and I piled everything up together so nothing would get lost.

I was trying to figure out if I left a shield off the engine. There are a couple of threaded holes in the head but I have no leftover fasteners.

 

[ILENGINE]

The top of that heat shield is held in place by the blower housing. The offset notch sides onto the blower housing.

 

[motoman]

I do believe Briggs has (had) a quality problem. In my case the Intek 24 failed with a pushed valve guide in year 2 from new after very careful use on 5 acres. To this day no one has explained why this happens . I believe it may be a combination of things. With oil pressure and oil temperature gauges installed after the failure I have monitored this engine since I disassembled it. The assembly clearances (fit) for the guide to head were ok. You cannot buy a guide for replacement which tells me Briggs knows they have a recurrent problem (and so do others).

I have installed a temp probe and have seen cylinder head temp of 305F. I could not drive it higher in summer under load, but could not measure the guide area exactly. It is possible that excessive heat softens the aluminum alloy which loosens its grip on the guides. It is not Briggs who does the system design. I believe the 3 bag system loaded with damp grass and operating on grades in summer pushes the Briggs oil temp above 300F which will not in itself cause failure but which inhibits overall cooling. Although I still use the bagger, a better idea is a sweeper. Also Briggs furnished a replacement head which has not been a problem and the other head has never acted up. Briggs depends upon receiving alloy heads with a certain composition and without inclusions, etc. At the price point Briggs is probably accepting paper certs and not doing any characteriztion of the received head material. I have the failed head and have been tempted to have the head Brinell tested (softness), but no enthusiasm in the forum. My 2004 DYT 4000 is still running well although I feel a little trans slip in cold weather . Don't know the hours 'cause the meter went away long ago. Oil pressure hot is about 35 psi.. I am using 5W-30 Mobil 1 only because wife's fancy car uses it.

BTW I hope you know you cannot simply replace rings like a person does with a sink washer, or you will be taking it apart again. Right gang?:2cents: