1G Inspecting gears and front case from 1990 6 bolt

[Brandon Nicholson]

I’m taking apart this 1990 6 bolt with straight cut gears/case and I’m looking for some general advise on how these look and what I should do about the front case since I’ve heard mixed emotions about using miss-matching parts, with a straight edge and some feeler gauges I can just fit a .09mm under them, gears have some age on them but no grooves that I can feel with my fingernail. Its within spec but on the wide side and it concerns me.. The wear looks to be from the case and I feel like a new case would get me closer to a better spec but would like some input on what you all think. I’ve taken pictures of the gears and pump housing. In my opinion the housing looks to be too worn but I feel like the gears can be detailed and deburred and put back in service. What do y’all think?

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[luv2rallye]

This may help:

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[Brandon Nicholson]

This may help:

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Jafromobile! I’ve watched this specific video a few times And got my specifications for the gears coming in at .09mm on both the drive gear and driven. This is in spec but on the wider side. I’m thinking a new case will bring me in a better range but even jafro says not to mix spur gear and helical gear cases due to machining differences. I would love to find a new straight cut case but it seems like that is very hard to do at this time. And I see people building new cases with spur gears quite often even in some evos so I’m not sure what to do as I don’t want to f about with the heart of the system

 

[1990TSIAWDTALON]

I see scoring on the back side of both the drive and driven gears. That scoring will effect pressure as it is suppose to be a smooth surface to seal against the case and cover (which I can't see real good but suspect some in the case and cover also).
I use ACL pumps and take them apart, check them for spec and reassemble with assembly lube for fast oil pickup on first start up.

 

[Brandon Nicholson]

I see scoring on the back side of both the drive and driven gears. That scoring will effect pressure as it is suppose to be a smooth surface to seal against the case and cover (which I can't see real good but suspect some in the case and cover also).
I use ACL pumps and take them apart, check them for spec and reassemble with assembly lube for fast oil pickup on first start up.

The groves that are seen on the gears are flat and cannot be felt with my fingernail, the housing has some general wear but the car didn’t suffer from an oil related issue. This was a running engine with good oil pressure. Just in for rebuild.

I’m not really sure what to do cause I want a reliable pump with spur gears. I understand some get away with helical gears but I seem to find them failing prematurely due to their design. I’m looking to wring things out with my auto and want to make sure everything is set correctly

Marty, how long have you been running ACL pumps for? And no Ill affects? I’m most concerned about the helical gears eating into the pump housing and causing a failure.

 

[1990TSIAWDTALON]

I have ran the aftermarket ACL pumps since 2015 Brandon. They are on hi revving motors too. I have not had any issues BUT..... I don't put a hell of a lot of miles on those cars since I don't daily drive them. 1000 miles on the 92 Blue Talons motor and great oil pressure. Same pump on a mostly stock 4g that we built to put into a 90 GSX body we have. I put one on my other sons 7 bolt that I built for him and it was working out great (until he melted a piston with too much timing). I am confident in them. I "think" some of the bad reviews about chewing into the case were related to bad dummy shafts that didn't have the oil groove in them. I will cross my fingers but since the straight cut gears are near impossible to find, I am using what I deem the best alternative (but an OEM pump is the best).
You can see those ACL pumps on these 3 build sheets.

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[Brandon Nicholson]

I have ran the aftermarket ACL pumps since 2015 Brandon. They are on hi revving motors too. I have not had any issues BUT..... I don't put a hell of a lot of miles on those cars since I don't daily drive them. 1000 miles on the 92 Blue Talons motor and great oil pressure. Same pump on a mostly stock 4g that we built to put into a 90 GSX body we have. I put one on my other sons 7 bolt that I built for him and it was working out great (until he melted a piston with too much timing). I am confident in them. I "think" some of the bad reviews about chewing into the case were related to bad dummy shafts that didn't have the oil groove in them. I will cross my fingers but since the straight cut gears are near impossible to find, I am using what I deem the best alternative (but an OEM pump is the best).
You can see those ACL pumps on these 3 build sheets.

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Well that takes off a bit of stress , and it’s a shame these gears are so hard to come by now(maybe someone could take these to a company and make replacements??). I too think a lot of the failures are due to non oem BS shaft and or not simply cleaning and detailing the new pumps. I’ll have to give the newer style pumps a shot and hope for the best since spur gears/cases are impossible to find now I will keep these gears just incase.
Other then deburring the gears and making sure they don’t dig into the case is there anything else I could do to increase longevity?

 

[1990TSIAWDTALON]

Shot peen them and have them magnafluxed for cracks is about all i could think of. I have never heard of anyone Faceplating them, but I suppose that could be done also. I hadn't thought of that until now.

 

[DSMPT]

It doesn't look too bad to me, maybe still salvageable. Hard to tell by the pics though. Where you should check besides clearance would be the inside of drive gear shaft sleeve. If that part is worn, you have no choice, you need a new case and a cover. And if you don't feel the scoring on gears/case/cover by nail, it probably fine, but if you care and if the scratches/wears are just little, coating the gears and/or case/cover may be able to make it to revive. Can't 100% guaranty but since the OEM case/cover is expensive and the straight cut gears are discontinued, this could be an option for some case.

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[Brandon Nicholson]

It doesn't look too bad to me, maybe still salvageable. Hard to tell by the pics though. Where you should check besides clearance would be the inside of drive gear shaft sleeve. If that part is worn, you have no choice, you need a new case and a cover. And if you don't feel the scoring on gears/case/cover by nail, it probably fine, but if you care and if the scratches/wears are just little, coating the gears and/or case/cover may be able to make it to revive. Can't 100% guaranty but since the OEM case/cover is expensive and the straight cut gears are discontinued, this could be an option for some case.

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The sleeve where the shaft rides in has some wear like you mentioned, no high spots or sharp edges but definitely worn..

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This pitting here is what concerned me most when I initially took it apart.

What about the use of a new case? I will gladly get a new oem case but have heard mixed emotions on mixing the gear/case style. (For instance What are people doing to use straight cut gears in their 7 bolt motors?) extremepsi sells the helical style case but have read the tsb it states that the housings are different.

As for the gears themselves what coating is that on the picture you uploaded? Is it sort of like skirt coatings on pistons? I was having that thought earlier today and was curious to see if anyone has done it and you answered it for me , has it been used with good results?

 

[DSMPT]

The sleeve where the shaft rides in has some wear like you mentioned, no high spots or sharp edges but definitely worn..

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This pitting here is what concerned me most when I initially took it apart.

What about the use of a new case? I will gladly get a new oem case but have heard mixed emotions on mixing the gear/case style. (For instance What are people doing to use straight cut gears in their 7 bolt motors?) extremepsi sells the helical style case but have read the tsb it states that the housings are different.

As for the gears themselves what coating is that on the picture you uploaded? Is it sort of like skirt coatings on pistons? I was having that thought earlier today and was curious to see if anyone has done it and you answered it for me , has it been used with good results?

If you can get a new case, that would be the best and the safest.
Why I mentioned to check the sleeve if reuse the old one is because if the sleeve is worn and oval, the shaft and gear wouldn't sit straight anymore and that would change the clearance and would possibly damage inside once you install the timing belt.

The coating on the gears and shafts in the pic is Calico coatings CT-10 coating (That's different from piston skirt coatings, it's more like bearing coatings and recommended by Calico for oil pumps). If you are interested in, you should ask them if their coating would work for your case. The coating itself is way cheaper than new gears, so if their coating would work to save your gears, that would be great since it's hard to find new or good condition straight cut gears.

David at Calico Coatings.
[email protected]
The coating in the pic is this one.
https://www.calicocoatings.com/coating-data-sheets/ct-10-dry-film-lubricant/