Questions about worn engine components

[motomatt]

Hi everybody, longtime lurker, first time poster. I'm working on a 1971 Ambassador. I have the engine apart and I'm in the process of acquiring parts for a rebuild. I'm curious about a few things that I am finding, and having found no answers using the search, have some questions for the group:

1. How much camshaft end play is acceptable? With the bronze thrust bearing and timing gear in place, I measured 0.004" (~0.01mm). Is this acceptable, or does the thrust bearing need to be replaced? I should add that the distributor gear was pretty badly worn, but the wear was uneven, possibly due to poor heat-treatment? Or is this related to the camshaft end play being excessive?

2. I plan to install a new oil pump. How much wear on the engine block from the oil pump gears is acceptable? There are 2 circular patterns on the front machined surface that the oil pump bolts to. I can feel them with a fingernail. I have photos that I can post, but I can't do it at the moment. Will post the photos later.

3. The sealing surface on the rear end of the crankshaft is damaged (gouged), probably by a whatever tool the previous mechanic was using to pull the oil seal. I'd like to use a repair sleeve, but the size tables I've found don't list a size that matches the micrometer reading that I'm getting. The end of the crankshaft that the seal rides on is reduced a bit from the main journal size, which appears to be 2.125" nominal. I measured the sealing surface diameter at 2.085". Repair sleeve size tables show #99205 (shaft size 2.057" - 2.063") and #99210 (2.122" - 2.128"). Will the #99205 stretch enough to fit? Has anybody else done this?

Thanks for helping with this.

Matt

 

[john zibell]

The oil pump may be your biggest issue. As far as I know the oil pump is no longer available for the gear driven engine timing . That are still available for timing chain engines. You need to get a factory workshop manual that lists the dimensions and under/oversize dimensions for rebuilding. For the crankshaft, I think your easiest solution is to have a machinist make a sleeve to the original dimension that you need after turning down the crankshaft. Original dimension for the crankshaft is 53.970 to 53.931mm or 2.1248 to 2.1233 inch. The dimensions are from the factory manual that Premier motors released in the 70s.

 

[scottmastrocinque]

I'm thinking MG Cycle still makes gear driven oil pumps to order but they aren't cheap at nearly $400 when I last looked. There is a used one on FleaBay for $50 but you take your chances there.

 

[motomatt]

Thanks for replying. I tried to explain the issues I was seeing in the clearest possible manner. Looks like I missed it. I will try again:

Camshaft: The journals mic in spec for diameter. The camshaft end play (axial movement, fore-and aft movement) measures 0.004" Is this acceptable? I cannot find any figures for this in the factory manual that Premier motors released in the 70s.

Oil pump: As stated, I plan to replace it. They are available, new manufacture, from HMB in Germany. My question was about the witness marks (wear marks, whatever you want to call them) caused by the spinning gears running on the front of the engine block. How much is tolerable? Should I worry about it?

Crankshaft: The aft end of the crank, that the rear main seal rides on, has a reduced diameter for about the last half-inch or so (image attached). It is smaller than the dimensions the John has quoted, above. Has anybody used a repair sleeve on one of these? (trade names: Redi-sleeve, Speedi-sleeve, etc.)

 

[Moto-Uno]

Your camshaft end float is fine .
Without a clear picture of the oil pump wear marks , judgement will be sketchy .
In the past I'd used a Redi-sleeve on the alternator rotor on my Le Mans 2 , worked fine .
If the gouge is under say .020" , you might consider having it turned down , the crank
seal has significant squeeze on the crank . Peter

 

[john zibell]

On you camshaft free play, It wouldn't hurt to replace the bronze thrust plate while you have it apart. 0.004 inch may be acceptable, but I's rather see it around 0.001 to 0.002 inch. Then replace the drive gear on the distributor.

 

[john zibell]

I'm thinking MG Cycle still makes gear driven oil pumps to order but they aren't cheap at nearly $400 when I last looked. There is a used one on FleaBay for $50 but you take your chances there.

Thanks for that Scott. When I had to replace the input impeller for a 72 Eldorado (timing gears) oil pump, I picked up the last one Harper's had and they were not available from Guzzi.

 

[john zibell]

Crankshaft: The aft end of the crank, that the rear main seal rides on, has a reduced diameter for about the last half-inch or so (image attached). It is smaller than the dimensions the John has quoted, above. Has anybody used a repair sleeve on one of these? (trade names: Redi-sleeve, Speedi-sleeve, etc.)

View attachment 27471

The dimensions in the manual are for the part that is in the rear main bearing. Moto-Uno's suggestion to torn the area down is a good one, or change the rear main seal position slightly by not seating as deep. That is the factory seal driver places the end of the seal slightly inboard of the rear main bearing housing. Try a flush to housing.

 

[Amboman]

Just my opinion...
Camshaft: .004" is fine.There should not be a ridge worn into the gear side of the thrust plate, if there is replace it.
Oil pump: Unless the swirl marks are deep into the case, then I wouldn't worry about them.
Crank: I've done as Peter suggests: having the seal area ground and polished to remove any imperfections.

 

[motomatt]

Here are some images of the questionable parts:

The first 2 show the camshaft thrust ring. It measures 0.271 - 0.273 thick. No wear ridges can be discerned on either side. I think I will replace it, mainly because the thickness is not consistent - one side is thicker than the other. I could not find any reference stating the nominal thickness of this part, nor any figures for allowable camshaft end play. So I thank you gentlemen for sharing your wisdom.

The second image shows the wear marks on the engine case caused by the oil pump gears. I think I will ignore this. It seems like the only solution would be a new block. I'll install a new oil pump and hope for the best.

The crankshaft gouge: I think I'll have the end ground at a machine shop. If they can clean it up before taking too much off, great. Otherwise I'll have it ground to fit the next size smaller repair sleeve. As you can see from the image, there isn't much of a "clean" surface for the seal to ride on. Installing the seal "shallow" might not give it enough purchase to stay put, I think. Pushing the seal further into the bearing would block the oil supply, so that's out.

I appreciate all the help. You guys rock!

Matt

 

[john zibell]

Looking at the end of the crankshaft, a machinist should be able to polish that and still have the rear main seal do its job. After it is polished slip a seal on it. If it has noticeable drag, it should be good.

 

[motomatt]

Thanks, good call. that's my plan, hope it's not too deep.

 

[motomatt]

To follow up: the crankshaft was repairable. The machine shop ground the sealing surface to 2.063 and installed the repair sleeve, which brought the diameter back to 2.085. I sent my camshaft and lifters to Delta Camshaft in Tacoma. They repaired the pitted lifters and reconditioned the camshaft to like-new condition, for a very reasonable price. I highly recommend them.