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Sorry for all the questions... After the experience with the valve guides, I'm spooked by just about everything that comes in the mail. So here's my next one. Comparing the new (i.e. reproduction) lifters to the old, seeing a slight variation in the dimensions of the new vs. old hydraulic lifters. The new lifters measure 2.475" long, while the old lifter was 2.440" long, making the new one longer by .035" The diameters are also slightly different, with the new ones measuring .5145", while the new ones are .5155", making the old ones wider by .001".

I will wholly admit this was a sample of just one, but I wouldn't have a reason to suspect they would vary significantly.

I'm checking the valve clearance with the tool/method recommended in the manual, but I don't think it takes into account variations in length of the lifter (or does it?). Will I have problems if I use these lifters? Thanks again for your insights, all...

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I'm interested to see the answers you get. We'll possibly be replacing lifters on my brother in law's car and I'm curious to see what people think of the repops.

For sure he has at least one failing lifter. I doubt that it will get better with cleaning, so I'm assuming replacement is out only option.

I will say, my micrometer and I are getting to become fast friends. I pulled all the lifters out of the tappets to see where they all were. Here's what I've got for initial lengths:

2.4520
2.4510
2.4490
2.4480
2.4435
2.4425
2.4425
2.4415
2.4410
2.4400
2.4395
2.4395
2.4390
2.4385
2.4375
2.4350

So it's already all over the map. The reproductions are also all over the map, and on the whole slightly longer.

2.4640
2.4615
2.4605
2.4605
2.4600
2.4595
2.4590
2.4585
2.4515
2.4505
2.4485
2.4475
2.4465
2.4465
2.4450
2.4440

Not sure the numbers mean anything, but I suppose that some variability was expected here given that the valve stem clearance is a range between .030 and .070 using the J-4540 tool. HOWEVER, I did also just remember that Merrit sells two versions of this tool - one for OEM-style lifters and one for replacement-style lifters. I have the OEM-style tool. Maybe that makes up for some difference? I know the OEM-style gauge is 1.1610" in length.

The difference in diameter is .001, which is probably not significant, but I would expect the new ones to be larger than the old ones, if not the same. The difference in length seems excessive, but the old and new ones seem to be within the same range. Perhaps they need to be collapsed to measure them, or fully extended, or something. I'm not familiar with that type lifter, but I'd say the diameter is OK, and maybe someone can answer the length question.

I think TxGoat has the answer.

The old lifters are different now because they might still be pumped up slightly or if relaxed, the lifter spring might have been compressed a bit over time. Same with the new lifters as there could be a variation in how they are sitting after assembly. I think the important measurement will be the body length from just below the spring to the tip to ensure that part starts out exactly the same so the lifters sit in the tappets same as the old. The diameter must also be very consistent as too loose will let too much oil leak out around the lifter and too tight and the lifter might bind in the tappet. That is one thing I would definitely check by doing a hand fit of each lifter in the tappet.

Once the engine is running and they are pumped up the tip to end measurement will change. The fact that the lifters might not all be the same is the reason they use the fixed gauge tool inserted in the tappet in place of the lifter to provide a solid measurement that is exactly the same for each valve. That way the valve stems can be properly ground to size for a consistent clearance by using a fixed and solid reference point.

Mr. Novice here again.

Seems to me that a small variance in the length of the hydraulic lifters doesn't matter as they are going to fit into space created by grinding valve stems to the correct length using the J-4540 Gauge. The lifters not needing to be exactly the right length, like mechanical ones, is one of the benefits of hydraulic lifters.

I don't believe the difference in diameter is significant or concerning. And it doesn't surprise me that originals would be a tighter/better fit.

I tested and used my original lifters, but I never measured them so can't provide any data regarding their dimensions.

Ah yeah, there yah go, that makes perfect sense. I wasn't going to go through them all again... the new ones don't go back together as easily as the old ones, but the variance there is more like .005" between old and new, and they are anywhere between 2.0020 and 2.0060. The old ones are smaller for sure, one was as small as 1.9995". Still, we're talking thousandths, not hundredths, which I would imagine is probably OK?

Quote:

If you are taking lifters apart, be sure you don't change parts from one to another as they are matched.

I misread and thought the new ones were smaller. As Howard mentioned do a test fit of the lifters. As long as nothing is tight I don't think there is any reason for concern.

The picture of the J-4540 Gauge that I posted on your other thread appears to be 1.478", which is longer than what you mentioned. Not sure what that's about.

Oh no worries, I've at least sort of done this part before. We're just going one at a time. I'm not sure why the tools are such different lengths, but I did want to confirm that the two sold by Merritt are different. The replacement-style is .08" longer than the OEM-style, definitely enough to throw off the measurement a give a false reading.

And I think I've figured out all my issues. Just for practice, I went and lapped one of my valves, put some brake clean on the valve and blew compressed air to test the seal, put my thumb on the valve, worked great - no bubbles. Checked the clearance with the OEM-style gauge, it came to .040". I thought "great, we're in range, no grinding needed." Put it together with a lifter in place, new spring, etc. and could not get it to stop bubbling. Now, it makes sense... that .040" I measured with the OEM-style tool is really -.040" when you take into account the difference between the two tools, significantly out of spec and definitely in need of an adjustment to the stem.

I'm going to grab a replacement-style tool from MM, and we'll make lapping/grinding an exercise for each valve. I BELIEVE this was my error the last time I did these checks. I THINK the lifters in the car are not OEM - they're also replacement-style. I know this is true for the 356 lifters, but I believe the one cosmetic difference between an OEM-style lifter and replacement is the presence of a little mushroom shape at the top of the plunger body. I don't know for certain that this is true for the 327 lifters (the replacements are just straighr cylinders). If so, it explains why I was seeing some compression issues the last time I tried lapping my valves. I was getting false readings from the gauge I was using. Onward.