Replacing Valve Stem Seals - Other Parts Too?

[eramljak]

Howdy Folks!

I have an old (skool) GSX-R1100 engine, 1991.  She is burning oil, most noticeable on start up. I've checked for leaks and found none. I've not done a compression or leak down test, so it could be rings, but it seems most likely to be the valve stem seals.  when I look into the intake ports, I can see some ( not all ) of the valves and intake with oil marks and build up.

I'm going to replace the valve stem seals for sure.

My question is : should I expect to replace the valves too? what other items should I replace while I have the head off?

I'm not sure I can spend much money to get into serious head work, like redoing the valve seats. I will be doing the work myself and the extent of it might be a port and polish.

Due to the age of the motor; what items should I be on the lookout to replace?

 

Thanks!

[Gixer1460]

Seals - more than likely. Other things to look at is wear in the guides ie. check for valve rock. Also check valve stem diameters - they don't often wear but the guides do. They can be DIY replaced but not an easy job - easy if you have a press and a reamer to final size them. Regards porting don't go mad and DO NOT polish the inlet - you'll lose airflow!

[Jaydee]

1 hour ago, eramljak said:

might be a port and polish

A shiny flat surface also promotes condensation (gives atomised fuel something to stick to) which builds up and get pulled in to the chamber as droplets. Better off leaving a rough texture. One less job to do also.

[Dezza]

On the parts fische there is a small o'ring for each valve. Presumably they are also required during a head re-furbish (?????).  Also, genuine Suzuki valve stem seals are currently on offer at Robinsons Foundry at less than 2 quid each in case anyone is interested.

[eramljak]

Thanks for the great and quick answers!

Those are good tips regarding the intake side of the head. I will check out the valve guide wear.

And I am looking into Robinsons now. they don't have a listing for 1991 GSX-R1100, but they do have 1990. similar enough to use the same seals?

[KATANAMANGLER]

The seals are all the same for the oil cooled GSXRs.

[clivegto]

& b12's.

[Gixer1460]

7 hours ago, clivegto said:

& b12's.

Yeah but they really don't count being 'low rent' types LOL! Don't be tempted to economise with aftermarket they do go hard earlier than OEM and if on offer @ £2 - £32 + vat and post - ain't that back breaking!

[Dezza]

At the moment the OEM seals from Robbos are significantly cheaper than 'performance' or other aftermarket seals or am I missing something here? I ordered a set for an 1100 slabby head and the whole set of 16 was less than 30 quid. I try and order at least some of my Suzuki parts through my local bike shop but at the moment Robbos is doing mega discounts on many parts but you can only find out which bits are discounted by trawling their parts fisches for hours, and who would be sad enough to do that (rhetorical question of course)

 

Arrived this morning with other discounted bits. The seals are 1-54 each plus vat so get them before they stick the price back up to 7 quid each.

Edited June 15, 2019 by Dezza

[KATANAMANGLER]

Every time they are on offer I buy a set and stick them on the shelf. Just used my last set. 

[1100fred]

Did the same with sump gaskets and stocked up at about £4 each 

[B12Mick]

Picked up a set of valve stem seals and a base gasket from Robinson's 2 weeks ago for future use - normally check their website every couple of weeks

to see whats been discounted.

[eramljak]

@DezzaThanks for the tip about the sale. I just bought a full set and shipped to Canada for much less than any other option out there.

So, I have the 1991 engine which uses the valve shims, rather than tappets and screws. In your experience, do you end up going bigger or smaller on the shim thickness? Do things get tighter or looser?

[Dezza]

39 minutes ago, eramljak said:

@DezzaThanks for the tip about the sale. I just bought a full set and shipped to Canada for much less than any other option out there.

So, I have the 1991 engine which uses the valve shims, rather than tappets and screws. In your experience, do you end up going bigger or smaller on the shim thickness? Do things get tighter or looser?

I have never worked on a shimmed Suzuki engine but on my old Kawasaki if anything needed doing it was usually because the clearance had closed up, presumably due to seat wear so a thinner shim was required. Often you can move shims between valves to get your clearances right and only have to buy one or two extra if at all. I do not know what will be the case after a head refurb though but someone less ignorant than me will hopefully be along soon.

[eramljak]

OK, that makes sense. the seat wears out and the valve is able to move further which reduces the clearance between the shim and the cam lobe.

[B12Mick]

I bench shim the heads for the engines I build at work and set them to the top end of the tolerances so when the 

heads are torqued down on the crankcases, the clearances normally end up cock on in the middle of the spec.

[Gixer1460]

11 hours ago, B12Mick said:

I bench shim the heads for the engines I build at work and set them to the top end of the tolerances so when the 

heads are torqued down on the crankcases, the clearances normally end up cock on in the middle of the spec.

How does fitting the head to the bottom end affect valve clearances - the two are not interconnected?

[B12Mick]

A few tenth's of a thou distortion when the heads on the Subaru flat 4 are pulled down can upset the valve clearances especially when using oversized14mm head studs for high boost applications on them.

[markfoggy]

On 6/16/2019 at 9:08 PM, Dezza said:

I have never worked on a shimmed Suzuki engine but on my old Kawasaki if anything needed doing it was usually because the clearance had closed up, presumably due to seat wear so a thinner shim was required. Often you can move shims between valves to get your clearances right and only have to buy one or two extra if at all. I do not know what will be the case after a head refurb though but someone less ignorant than me will hopefully be along soon.

^ this,  If you leave them too long they run out of compression when cold and don't like starting, run fine when hot with no other signs of problems. Also is difficult to spot, 'cause they never get noisy.

[Gixer1460]

5 hours ago, B12Mick said:

A few tenth's of a thou distortion when the heads on the Subaru flat 4 are pulled down can upset the valve clearances especially when using oversized14mm head studs for high boost applications on them.

So you are using 'evidence' from a car, two cylinder head , modified for excessive boost against a 4 cylinder head with normal studs and torque fasteners - talk about comparing oranges and bananas!

[markfoggy]

He has a point, Moto GP bike will now have this problem,

They are watching us. 

[B12Mick]

1 hour ago, Gixer1460 said:

So you are using 'evidence' from a car, two cylinder head , modified for excessive boost against a 4 cylinder head with normal studs and torque fasteners - talk about comparing oranges and bananas!

Just saying that I find it easier to bench shim heads after they have been overhauled ( unless they are screw and locknut adjusters ) be it car or bike heads I'm doing at the time.

Apologies to the OP if this is going off topic.

 

[eramljak]

Thanks for the discussion! I sort of drifted away from the original question, so it's all good from my perspective!

I received my shipment of seals yesterday, so now I need to figure out how quickly I can get this done.

It has been some time since I overhauled a cylinder head, and I'm really looking to do "just enough" to get this done.  Should I do anything with the valve seats? clean them with any kind of abrasive? or is it a better idea to find someone to machine the surfaces? or just some solvent and elbow grease?

I'm not looking to add any power at this time, so I would like to leave well enough alone, but I imagine that there will be some build up around the valves and seats. I don't want to do any damage when cleaning this up.

Thanks!

[Gixer1460]

Oily / soft gunky residue - clean off with petrol / solvent / thinners. Anything harder can be tackled with a BRASS wire wheel tool - don't be tempted to use a steel version as it can scratch seats. A flap wheel using Scotchbrite material works well. Valves can be cleaned if chucked into a drill using Scotchbrite. Nothing needs a 'mirror' finish just clean. Unless the valves or valve seats have been burnt or are pitted they won't need re-cutting, and if valves are going back into the same position in the head, they won't need grinding / lapping - some do it but it is unnecessary (the factory doesn't do it with a new engine!) as clean valves and seats, banging together 8x a second at idle, soon wear in together! Be careful with the valve seals, they can be a bit tight - sitting them in warm oil before fitment sometimes helps and make sure they are fully seated as valve spring retainer will bash them and then you'll be doing the job all over again!

[eramljak]

Thanks @Gixer1460!