Base gasket surface sealing after prev.owner gasket scraping ...?

[Chuck78]

I'm putting together a budget GS750/850 engine here out of the best used parts I have without visiting a machine shop to get cylinders bored etc.
The cylinder I picked out of my 4 or so 850 jugs honed up really nicely & got rid of a few vertical score marks & rust stains without taking it much at all beyond new spec on bore diameter.
I resurfaced the deck on it, took 0.1mm off.

Base gasket surface is a different story...

Refer to photos & give me opinions...

[Chuck78]

Previous owner did an impatient hack job on scraping the stubborn/stuck base gasket remnants off, and gouged it out in some areas. Looks worse in person, sorry my cell phone camera lens is very scratched/cracked & can't focus well anymore

[Chuck78]

Keep in mind that these are the outside 4 corner stud areas, and the egg-shaped 2 at the rear double as the primary oil feed passages to the head. The 2 at the front are lesser pressure as they are after half of the oil has been delivered to the valvetrain

[Chuck78]

Does anyone have experience with installing a cylinder that had some gasket scraping gouge damage like this? The marks that appear a bit wider are pretty noticeable, they don't look so bad in the photos but are worse in person.
Should I just put a dab of RTV silicone in these areas, & smeared on the egg-shaped oil pressure o-rings, & run it?
Or has anyone experienced a lot of leaking problems with similar?

[Nessism]

I doubt those marks will cause an issue. I wouldn't use RTV but a light coat of Gasgacinch on the gasket wouldn't hurt. Be sure to use fresh OEM gaskets and O-rings too.

[Chuck78]

I doubt those marks will cause an issue. I wouldn't use RTV but a light coat of Gasgacinch on the gasket wouldn't hurt. Be sure to use fresh OEM gaskets and O-rings too.

Ahhh yes thank you Ed... I was worried about RTV on oil pressure areas, possibly flaking off & being fed through the oil passages...
I believe I have a similar product to Gaskacinch or Hylomar, the really REALLY tacky sticky gasket sealant stuff... Hi-Tack or something similar, from NAPA. I previously have only used it installing brass freeze plugs into water-cooled automotive engines. Seems the perfect solution here. Some leaked out in a milk crate on my shevles, & the whole crate was practically glued to the shelves afterwards...STICKY STUFF!


If I had a boring bar or more time to take to a machine shop, I would've chosen a different cylinder & bored to 870cc...
Was not really wanting to heat up & press out the sleeves to do a light skim on resurfacing the base gasket area...Thanks for the encouragement, Ed ��

[Grimly]

After much careful soaking, waiting, scraping; more soaking, waiting and scraping, my base gasket area looked a bit like that. The old gasket had transformed into a Rockwell-graded hardness of industrial linoleum, fit to grace the hardest institutional floor.
A coating of spray Hylomar dealt with it.

[fbody_mike]

I was going to suggest some Permatex Anaerobic Gasket Maker, as it is designed to fill in scratches between gaskets, but I see it has a 300 degree F upper range. These air cooled engines can get to those temps on really hot days, check the operating temps on whatever you decide to use.

[Brendan W]

Mine was a bit like that, must be four or five summers ago. I sprayed the base gasket with hi temp aluminium paint.
Can't say it wouldn't have been okay without. Just felt it needed a bit of insurance.

[fastbysuzuki]

A spray with blue hylomar will sort that out no problem.

[bwringer]

Several good recommendations here; overall it's mainly important that you DO NOT use RTV.


Personally, I would use a light coat of semi-hardening case sealer. It's done the trick for me in similar situations many times. As noted above, old base gaskets are damn near diamond hard and seem to be impervious to chemical attack. Scratches are close to inevitable.

Threebond 1194 has never once failed me. I guess it's been replaced with 1184:

https://www.amazon.com/Three-Bond-Sealant-Liquid-Gasket/dp/B007TWXI1K

There's also a Yamabond case sealer that's pretty much the same thing and may be more easily available in your local dirtbike shoppe, and I'm sure Honda and other brands sell the same sort of useful glop under their own brand names.

You will NOT find anything like this in an auto parts store, but if you don't want to order online most powersports shoppes should have a decent brand of case sealer on the shelf.


As for the gaskets and o-rings, do NOT even consider using anything except genuine Suzuki OEM parts.

[Dogma]

I've used a smear of Suzuki's 1207B in that spot with good results, but I think that counts as RTV.

John Pearson told me to use the green (fine) Roloc Scotch-Brite surface prep disks to get old gaskets off. That definitely reduced the number of scratches and gouges I made. 3M stopped making them, according to the guy at KOI (who had the part numbers memorized). The knock-off brands work. I've been looking for a new source, since I'm tired of getting the assortment pack from HF. I guess I'll have to order a box of them from Amazon next time.

[Steve]

... I'm tired of getting the assortment pack from HF.

You don't have to get an assortment. They are available in a 5-pack of the same item.

https://www.harborfreight.com/3-in-fine-grade-fiber-surface-conditioning-discs-5-pc-61584.html

.

[kochic]

Mercury Quicksilver Perfect Seal is good, it never harden.
Marc

[chuck hahn]

I also do a very thin wipe of 1207B on base gaskets if they are perfect or not..by thin i mean just enough to see its there. Ive never had anything break off and plug oil passages or any other issues for that matter. Why do i do this?? Put together an engine and have that base gasket leak and youll know why.