71 Cam change with engine in?
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 1,084
Likes: 54
From: Grand Rapids Michigan
71 Cam change with engine in?
The repair shop has informed me that I have several collapsed lifters due to a blown head gasket that allowed gunk in. The head gasket issues have been taken car of but after restart and driving a while the noises started. They tried to clean them out but it didn't help. The shop wants to just replace lifters but I've been advised against that by many friends etc. They all say I should change the cam with the lifters. My question is can the cam be changed without pulling the engine? Small block 350. Thanks Mike
Team Owner
Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Yes, you can and I've done it before. But it's a PITA. You take out the radiator and all the stuff off the front of the motor. The pita is taking out the oil pan bolts and prying it down in the front to get the timing cover lip out. Then you have to goop silicone back on re-assembly to get the oil pan to seal up. It was something I did when I was young.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Yes, piece of cake. Done by many including myself. Even if a A/C condenser is in the way. Its really not a bad job but does require some specialty tools.
For what its worth:
You can put new lifters on a new cam.
You can put new lifters on a old cam.
You can put old lifters on a old cam (in same position)
You can not put old lifters on a new cam.
You can also switch mechanics. Collapsed lifters due to head gasket? H-m-m-m-m-m. Never heard that one.
For what its worth:
You can put new lifters on a new cam.
You can put new lifters on a old cam.
You can put old lifters on a old cam (in same position)
You can not put old lifters on a new cam.
You can also switch mechanics. Collapsed lifters due to head gasket? H-m-m-m-m-m. Never heard that one.
Burning Brakes
Joined: Dec 2017
Posts: 1,043
Likes: 414
2023 C3 of the Year Finalist - Modified
It is recommended to change lifter and cam as a set. I can provide the explanation if you’d like, but you might have already heard it. It is possible to change the camshaft with the engine still in the car. I’ve done it once before. Just pull the radiator. I would advice to be very careful during the actual swap. It is much harder to ensure the cam is perfectly straight and you can definitely damage the cam bearings if you aren’t careful enough.
You could also gamble and just change the lifters, it’s a risk, but I’d consider it if your current set up doesn’t have many miles on it.
You could also gamble and just change the lifters, it’s a risk, but I’d consider it if your current set up doesn’t have many miles on it.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
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From: At my Bar drinking and wrenching in Lafayette Colorado
Never heard of a bad head gaskets causing "gunk" that made the lifters go bad. If they had the heads off and you have valvetrain noise, it's more likely that you have a lifter adjustment problem and not bad lifters. I would do a good, correct lifter adjustment first, and verify that the rocker arm lock nuts are not loose and backing off. If the lifters really are collapsed and noisy, I would verify that you do not have flat cam lobes. If the cam lobes are good and only the lifters are bad, replace the lifters and leave the cam, if you like the current cam.
Lars
Race Director
Joined: Jul 2015
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From: SW Florida.
After adjustment, disable Ignition and cranking on the starter and watch all the rockers. Put on valve covers and fire up engine. New lifters? Treat it like a new flat tappet Cam break in period 30 minutes at a decent rpm not idle not 5000. Then pull the valve covers and crank it and watched the rockers see if they're all moving about the same amount. Some lobes will be opening less a little bit less is one thing. If you have any that open significantly less than the rest. it's time for a Cam. NOTE" If you drive it around and it doesn't miss and runs smooth it will work well enough to drive around on Sunday. Should get thru summer to plan and finance next engine adventure.
Last edited by derekderek; Feb 22, 2020 at 01:23 PM.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
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From: Unreconstructed, South Carolina
There's a real possibility ... and even likely with noise ... that the cam is damaged. It's not as involved as pulling motor, but it ain't necessarily easy either.
Considering the time required, don't cheap out ... replace both cam & lifters ... Summit has C&L kits for sbc as low as $112 ... depending on mileage, perhaps replace timing set as well. YMMV
Considering the time required, don't cheap out ... replace both cam & lifters ... Summit has C&L kits for sbc as low as $112 ... depending on mileage, perhaps replace timing set as well. YMMV
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Race Director
Joined: Jul 2015
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From: SW Florida.
50 bucks in lifters and rocker nuts I think is an acceptable loss if it turns out to need a cam. You don't wanna buy a cam till u have heads, intake, exh etc so you can get bang for yer buck for a cam. These cars these days do 50 to 500 miles a year. A worn cam should hold up a year or two unless valves barely open.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
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From: Cool Northern Michigan
Never heard of a bad head gaskets causing "gunk" that made the lifters go bad. If they had the heads off and you have valvetrain noise, it's more likely that you have a lifter adjustment problem and not bad lifters. I would do a good, correct lifter adjustment first, and verify that the rocker arm lock nuts are not loose and backing off. If the lifters really are collapsed and noisy, I would verify that you do not have flat cam lobes. If the cam lobes are good and only the lifters are bad, replace the lifters and leave the cam, if you like the current cam.
Lars
Is my vette stock?? HAHA
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I would get a new shop. It sounds like they dont really know how a flat tappet cam wears and what can actually cause them to go bad. Head gaskets can cause radiator coolant to contaminate your oil and if its bad enough it can get into the cylinders and cause hydro lock. But to just cause a few liters to go bad?..... Find a new mechanic, these guys are dangerous to your car and your wallet.
