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Technical 327 build advice

Discussion in 'The Hokey Ass Message Board' started by Fry, Jul 29, 2019.

  1. Long story short 2500 miles in my cam is starting to go flat. Ended up catching it early as it pulled a rocker stud. Noticed a few valve stems worn from rockers sliding. The break in was by the book and went smoothly so I'll save those details and questions for another thread.

    Here are the current specs on my engine, fully machined and cleaned up, new bearings, etc, stock forged crank and rods, silvolite cast pistons, 9.5:1, .040” bore, lunati 10120702 (262/268) cam, pertronix distrib, rebuilt 461 heads 1.94 valves, 650 Holley "classic", edelbrock performer eps intake, ram horns, 2.5” exhaust.

    It’s in a 2500 lb model A, super T10 wide ratio (3.42 1st gear), 3.00:1 9” rear and 7.50/16 tires.
    (The gearing is the same as a th350 2.52 1st and 4:10s but I get a poor mans overdrive.)

    This current combo makes for a good driver, runs great, stays cool, smooth through RPM. It wasn't a dog, but I wouldn't call it fast or powerful. The mileage wasn't great either, (15 mpg highway at 2000 RPM). It would be nice to increase atleast one of those two things. I admit I didn't do much for tuning, the plugs always read right and it ran great virtually out of the box.

    So now I'm debating if its worth it to dump more money into these heads (screw in studs, valves) and continue going slow, or step up to aftermarket heads. Also unsure which cam I should go with for either scenario, though I'd like to match it to as many current parts as I can.
    Originally I wanted a pre-64 look, though I'm caring less about that so keeping camel humps is a nice idea but isn't mandatory.

    Will aftermarket give me a big noticeable change with my current components? If so what specs should I look for in new heads? If I go new heads it'd be nice to step up in cam size if possible, any recommendations?

    Is a hydraulic roller retrofit worth the cost to try and prevent this from happening again?

    I am leaning more towards tuning up these current heads but it would be nice to get more power out of this thing. Is there a better cam choice for my current setup than this Lunati 262/268 cam?
    Would there be any benefit to roller rockers? I had just ran normal steel rockers previously.

    Is there anything else I should consider changing or doing when putting this back together. (I will check the bearings and bottom end for debris when I get it on the stand).

    It's a street car, mostly around town with some highway, the odd long highway trip every couple of years, maybe a run down the strip once a year. Reliability is number one priority, second is for it to be fun to drive, I want more power but I don't have to keep tearing it down every 2500 miles. I also would consider re-gearing to a 3.50:1 but I don't want to render 1st gear useless. I had hoped spinning so low on the highway would have got me great mileage but that didn't seem to happen.

    Thanks for the advice.
  2. Deuces
    Joined: Nov 3, 2009
    Posts: 17,982

    from Michigan

    Roller cam and rockers will cure the "go flat" cam blues..... :cool:
    wraymen likes this.
  3. squirrel
    Joined: Sep 23, 2004
    Posts: 44,337


    is it running around 2500 at highway speed? or more? or less?

    I went to hydraulic rollers on big blocks to help them survive, it works. Big bucks one time, no more trouble with cams going out, though. Make sure you get all the other parts of the valve train up to snuff.

    220 to 230 degrees at .050 lift is reasonable for a car set up like yours is, I think. If you really want mileage at highway speeds, you need a really small cam, or one with very fast ramps. It might be that mileage really isn't that important?
    bonneville bones and Fry like this.
  4. Jmountainjr
    Joined: Dec 29, 2006
    Posts: 888


    If you want mileage your cruise RPM needs to be about in the midpoint of the torque range. So yes, if the cruise RPM is too low your performance and mileage will suffer.
    Fry likes this.
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  5. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,467


  6. Thanks Jim(s), its running at 2000 RPM at 65 mph. Seemed to not load up and had plenty of pickup without having to down shift on my last trip through the Rocky mountains.

    Mileage isn't that important, I think for what I'm getting it should be a little more rank of an engine. I'd take less mpg to make more power for sure. I had just assumed I could have squeezed more out of it, for a light car, low rpm with such a mild engine. RPM range for the cam is listed 1400-5700. Maybe a rear gear change might be a good idea...

    I will consider a roller setup, it wouldn't be a waste with these heads would it?
    I just wouldn't change a thing about the break in, so I'm really interested in not having this happen again.
    Is there a certain roller cam I should consider? I'd like to find like a complete matched conversion kit, cam, lifters, springs, etc to ensure I don't screw up that process. Which rockers would be recommended?
    Thanks for the help guys.
  7. DDDenny
    Joined: Feb 6, 2015
    Posts: 12,891

    from oregon

    Boy, that engine combination all sounds good, checks all the boxes for me.
    The 268 Comp cam I had in the 350 in my heavy Suburban ran real good, in a 327 I bet it would run great also, considering the weight of the car and having a 4 speed.
    The 3.00 gearset and 16 inch tire combo is something you might rethink but if it is responsive at highway speeds (4th gear) it should be fine, at least you can control it by shifting down if it feels boggy.
    Just fix what's "broke", meaning freshen up the cam and lifters with equivalents to the existing ones, rockers, etc, doesn't sound like your wanting a big increase in hp.

    Desoto291Hemi and Fry like this.
  8. You do know many of those 327 engines ran like a Raped Ape using stock GM camshafts? Your engine already has the metal worn from the cam lobes circulated thru it. I wouldn't spent a lot on money on it. If It was Me I would go to the junkyard. find a 350 engine. Pull the cam and if its not worn put it and the used lifters in my engine. keep the lifters in order and its already broken in and tested and proven. And stiff valve springs are very hard on cam lobes. You gotta break a cam in with soft springs. Many times happiness can be had with stock factory cam and valve train..
  9. squirrel
    Joined: Sep 23, 2004
    Posts: 44,337


    Fry and saltracer219 like this.
  10. Fordors
    Joined: Sep 22, 2016
    Posts: 2,356


    If I understand what you are describing about the valve stem damage it sounds as if the tips are mushroomed. Is the damage confined only to the valves where cam lobes are going away? If so then it is a result of the excessive lash caused by the worn lobes, but if all the valves are showing damage you may have had the lifters adjusted with too little preload causing the rockers to “slap” the valve stem tips.
    The mushroomed tips will have to be dressed up before you could remove the valves from the heads, and it would not be enough to only dress them up and run the heads that way, the tips are no longer square to the stem so rocker damage will result.
    Depending on what you find new heads to go along with your new cam may be your best option.
  11. I have been using SAE approved synthetic oil since 1978, and this has eliminated my wear issues as wells as having improved my gas mileage.
    31hotrodguy and Deuces like this.
  12. Russco
    Joined: Nov 27, 2005
    Posts: 4,074

    from Central IL

    Go with a good Hydraulic Roller and Morel lifters. (I believe Morel makes a few of the others name brands roller lifters too like Lunati) Also make sure the push rod length is dead on and don’t look back. I also tried the Scorpion “Endurance” level roller rockers on my last build and they have been great too. You’ll make much better power and improve drivability and mileage at the same time.
    Fry likes this.
  13. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,279

    from So Cal

    This the same engine you posted pictures of the polished cylinders a week or so ago? I have to ask, what are you using for engine oil?
    Truckdoctor Andy likes this.
  14. 1934coupe
    Joined: Feb 22, 2007
    Posts: 3,523


    I'm reluctant to add my two cents but here goes, roller cams are great but millions of flat tappet cams where put in before and they didn't all go flat. My experience with cams going flat is that it happens in the first few hundred miles or so. Your combo sounds fine, I've used that same cam in a lot of builds. The rear end ratio sounds like more of a problem here than anything else, you should be running 3:50's and forget about a "poor mans overdrive" it's only lugging the car down. Now I read all the posts and as I stated this is only my 70 year old opinion . I bet the gas mileage would be the same with better gears than those 3:00 and 7.50 x 16 tires.

    scott27 and Old wolf like this.
  15. No tips weren't mushroomed, stem is worn side ways on 2 valves from rocker working itself off the side. Lobes were worn, I measured the cam to verify. Could probably clean up the end of stem, but for the money I should just replace them. Springs will have to have to be changed as they were for max lift of .490 and the cam was .489, and I'd like to try bigger lift maybe. (Will have to be changed anyway if I go with a roller cam). I also already have the screw in studs, I priced machining/tapping/pulling studs and its $200 locally for the pair. So I won't have too much more into these heads. I bought these fully rebuilt from the machine shop originally for $500 (canadian dollars), which I was comfortable at, just don't want to get any closer to the thousand dollar mark.

    Just if I'm going with heads, I'd like a good set like AFR or something. The problem is adding heads, roller conversion, freshening up the rest of the engine, misc parts, etc, I'm going to have way too much into this thing for a measly 350 horsepower. Makes a guy wonder if he should have just stuck an LS in there and spent the extra on a full hood.. :eek:
    ffr1222k likes this.
  16. Yes same engine, before I figured out the cam was the culprit.
    I used 30 weight diesel engine oil to break in with lucas cam additive.
    Changed oil after break in with lucas hot rod high zinc oil 10w30 I believe off the top of my head.
  17. I believe you are correct, I think that was an error on my part. Most seemed to agree it would be fine when I posted asking before I committed to this setup. I thought I could cruise at 80 and be in that 2600 RPM range. Though I generally stuck to that 65-70 range which kept it at 2000-2250. Which was a pretty good speed for the bias plies.
  18. I don't know anything about your background or experience in working with this kind of stuff. So I'm just putting this out there to clear up some potential confusion.

    Are you sure that you have a wear problem with your cam and lifters? Your first paragraph makes it sound like you've come to that conclusion because of the pulled rocker stud and excessive wear on the tips of the valve stems. In this case, one set of problems really doesn't have much bearing on the other.

    Of course the other possibility is that while working on the cylinder head problem you were able to visibly inspect and see the cam and lifter wear.

    Edit: OK... So you've answered my question before I was able to get it posted. :rolleyes:
    Last edited: Jul 29, 2019
  19. DDDenny
    Joined: Feb 6, 2015
    Posts: 12,891

    from oregon

    You know this but I'll say it to (anyone that will listen).
    Many flat cams happen long before the car leaves the driveway, the break-in procedure is critical.
    I've walked in on more than a couple of new engines (flat tappet) sitting idling and asked how long has this engine been running and been told "I just started it":eek:.
    You don't break in a cam by letting the engine idle, it needs to run for a period, (I know, the duration is open to debate) at an elevated rpm, preferably with a fan in place in front of the radiator long before reaching for the key.
    Also, mild hydraulic flat tappet cams don't need lightweight springs at break-in either.
    Last edited: Jul 29, 2019
  20. No the pulled stud and wear was mentioned as the symptom and to say that the heads require some attention.
    I checked with a dial indicator the lift on the ones I noticed as loose and saw the lift came up short.
    So took the cam out and measured and compared to initial specs. The ones noted as loose were indeed less than the others, but all showed wear.
  21. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,279

    from So Cal

    I would say that's not a rousing endorsement for the Lucas product.
  22. JeffB2
    Joined: Dec 18, 2006
    Posts: 7,804

    from Phoenix,AZ

    The Diesel oil may have been the culprit although diesel oils in most cases ''were" high in ZDDP they are also very high in detergents which may have washed the Lucas additive. Because of regulation most diesel oil regardless of brand is now much lower in ZDDP than it was five years ago so it's not really a good choice. Have your local Lucas dealer get this: Over the years I always used Isky Cam lube for break in and never a failure.
  23. better to use bar and chain oil than Lucas or any type of motor honey . I use Shell Rotellat 15 W 40 in everything including both my gas and diesel engines.
    Truckdoctor Andy likes this.
  24. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,279

    from So Cal

    This is not really accurate. First off, he used a straight grade engine oil, which means it met an older service classification, since no single grade diesel engine oils have met the performance requirements since like 1995. Zinc levels in diesel engine oils were reduced with the CJ-4 category in 2007, where a chemical limit was placed on the oils. Since then typical zinc levels have averaged around 1200 parts per million. Which is still considerably higher than passenger car motor oils of the HAMB era.

    Starting in 2017 the API did change the rules for those diesel engine oils that are "co-licensed", so if the oil carries both the CK-4 license, AND the SN license, then it must meet the lower zinc content of the SN category. If the oil is no co-licensed, and only carries the CK-4 or older license, then it is not restricted to the lower zinc content and will still have ~1200 ppm of zinc. I.e. Chevron Delo 400 is co-licensed and only has about 800 ppm of zinc. Shell Rotella T4 is NOT co-licensed, it will have about 1200 ppm of zinc. So you really need to look up he actual technical data sheet for the product and see what it says.

    Back to the straight grade diesel being the culprit because of high detergent levels. Well, we can't say much for sure, because we don't know much about it, but being as it was an older service category it probably did not contain a great deal of detergents in it. It was more like an old straight grade gasoline motor oil from back in the day, but with a higher sulfated ash level. If this caused the problem, I think it would have showed up before 2500 miles.

    What the engine shows to me is overall aggressive wear that is unusual for the hours of use. If Lucas 10W-30 has been used most of it's life, I wouldn't blame the oil that was used on breakin, I'd be looking at the oil that has been used most of it's life. Tell me, what service category does that oil meet? What API license does it carry?
    -Brent- and Truckdoctor Andy like this.
  25. Most of you probably do not realize this, Blues4U will, there are still new Diesel engines using flat tappet cams. The ubiquitous ISB Cummins still has a flat tappet cam and they go hundreds of thousands of miles with no trouble using “Diesel Oil”. As a matter of fact I’ve never seen an ISB flatten a cam. I’ve seen plenty of roller cam diesels flatten cams. Blues4U is right on the money about the straight weight oil, why would it have taken 2500 miles to show up. I also don’t believe in any oil additives, they are all snake oil. If these additives were really all that great, why don’t the oil companies install them so they can claim the benefits and charge accordingly.

    Sent from my iPhone using The H.A.M.B. mobile app
    olscrounger likes this.
  26. DDDenny
    Joined: Feb 6, 2015
    Posts: 12,891

    from oregon

    Yeh, I've gone a few rounds with guys trying to sell me on that Brad Penn stuff at twelve bucks a quart.
    Hotrodmyk and Truckdoctor Andy like this.
  27. I had emailed lunati asking for advise and their thoughts on the cam. I also sent them my measurements and asked what they thought of the wear. They never responded, typical.. I had the same response from them when shopping for a cam. Not sure why I bought from them in the first place....

    Since I don’t know the base circle initial measurement, I’m taking the current bc and taking that away from the total lobe to get total lift. Then taking that and multiplying it by 1.5 to compare the advertised lift. I don’t have my measurements with me so this is all irrelevant at the moment, but it showed noticeably less lift than it should have across the board, with the intake have greater wear than the exhaust.

    What I’m wondering is what everyone thinks about the wear pattern, is that a normal wear pattern? Just looks odd, like it wore a coating off irregularly or something. The bottom of the lifters look fine and flat as far as I can tell, no evidence of wear what so ever.

    I had wanted to send the pics to lunati for their thoughts but like I said they couldn’t be bothered to answer my emails, so I am permanently done with them. Comp has been helpful though.

    CCF890E6-69FE-4B47-AAF0-7835A56D0445.jpeg 124235AC-3D7F-400D-B451-E72BD3E6815C.jpeg FE05BF29-9062-40BC-AA6F-3D4C75E796A5.jpeg 044721FC-5EDB-44AF-B5A6-A951A4852C70.jpeg F750550A-A25F-4E45-B6D8-63F3660829A9.jpeg
  28. Hi Fry,
    To just look at the pics it looks like lack of lubrication to some extent.
    When I enlarged the pics it appears to have some journal wear or at light markings of wear.
    I don’t think it should with only 2500 miles on it?
    Maybe the oil was missing an ingredient or something,,,maybe a bad batch?

    When I looked at the lobes there seems to be wear down the side where the Parkerizing is missing,,,, I have never seen that with that low of miles.
    I assume you assembled the engine? Were the lifters easy to rotate in the bores?
    If they don’t spin it will wipe out the lobes very quickly,,,,,(at least they spin in a flat tappet cam engine). If no rotation,,,it literally scrubs the lobe right off.

    I saw your post where number 1 is reliability,,number 2 is to have fun and enjoy the car.
    I agree completely.
    You can’t get much more reliable than a good 327 with a hyd. Cam.
    If you have the money to spend go for a roller,,,,but it sounds like you want it to be dependable and not have to sink a fortune in it.

    The heads are the main problem,,,it pulled out a stud and has bad side wear on a couple of valves. That could have been missed by you if you didn’t do the head assembly?
    The guides could have been improperly serviced and/or the liners not installed correctly?
    If the guides had been replaced maybe the tops were not trimmed down and the retainers were bottoming out?
    Those heads are excellent castings,,,some of the best GM made.
    Good luck!
    31hotrodguy and Fry like this.
  29. One more thing,,,,,it will almost always turn out to be human error!
    I have never lost a lobe but once and it was my fault.
    There was a problem getting the engine fired and after break in or not long after I had a problem. That was on a 440 Mopar .
    Later I almost got hung up by the lifters tight in the bores,,,,you would not think a block back from the shop would be that way but it was,,, that was on a 350.
    My large journal 327 was very nice and I put a lot of rpm through that little Chevy.
    If the machine work is not spot on it will cause problems and that is usually out of our hands,,,all we can do is inspect the parts and mic them to the best of our ability . Some times the parts are defective as well,,,just roll the dice and hope for the best!
    Please keep us posted to your progress.

    Fry likes this.
  30. Thanks Tommy for the reply.
    I did not assemble the engine, my shop was too much of a mess so I had the machine shop assemble it to basically a long block.
    When I removed the lifters they seemed to come out and turn easily.
    The heads were done by another machine shop, one with a highly regarded reputation (wanted him to do my engine but was a year long wait). Everything was done to them as per the receipt, if trust the work, but who knows.

    If I wasn’t so gun shy now about flat cams I would skip the roller setup and instead spend the money on those fake trick flow double hump aluminum heads, instead of putting more into these. Maybe make some power out of this thing.
    Tickety Boo likes this.

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