New vehicle purchase, lifter tick

[Hyboost]

I recently bought a 86 GN with an engine professionally built by reputable builder.

My question is my lifters/rockers are quite loud. Fairly quiet at start up when cold, but gets louder when warmed up. Car has roller cam, Morel roller lifters, stock rockers. Excellent oil pressure at idle and at all rpm.

I see it has Comp cams push rods, (Pt# 7746-1) length 8.025 . I was wondering if these rods could be too short, causing tick? Not sure what to do or just live with it. Car runs great, traps 93 mph in the 1/8.

But sounds like an old small block with bad lifters. Anyone use the slightly larger rods? 8.050?
Or should I buy a p/r length checker?

Not sure if the preload on the valves is checked when motor is hot or cold? Won't they bleed down and give a false reading if rod is too long?

Maybe time to install roller rockers, but don't want to tear the heads off until end of season.

Thanks for any advice.

 

[kidglok]

It will probably be easier to get a set of roller rockers so you can properly set the preload. I'm not familiar with morel lifters, but if they are anything like comp 885's they are going to be a little noisy


Posted from the TurboBuick.Com mobile app

 

[pacecarta]

with stock rockers i would guess rod length should be around 8.150 with morrels ( .030 shorter if running steel shim gaskets., .100 shorter with roller rockers) but really depends on cam and the way the cam was ground.
best is get the pushrod checker , measure and go a little heavy on the preload (.040-.060, full turn on checker)

 

[jdpolzin]

There are way too many variables to be able to say what length push rod your going to need. Headgasket thickness, decking the block, surfacing the heads, base circle of the cam, height of lifters, etc.

Like Pacecar said, just get an $8 pushrod checker, take a valve cover off, let the car warm up. You'll have to block oil from spilling out of the head but thats easy. Then just check it quickly after you get the oil system pumped up.

 

[Hyboost]

Ok, thanks, I had the covers off last week, just to see what was in there. I pulled all the push rods, and they were all straight. The rockers were like new, no wear at all. But even when running, I could "hear"a lot of play in the pushrods, by that I mean ticking. And with a mechanics stethoscope, it was loud right at the rocker bar. And as soon as I shut it off I checked the rods, and they were all loose. And I mean loose, I could lift up on the rockers and get about .025 play between the p.r. and the rockers. I doubt the lifters would bleed down in the 30 seconds it took to shut off the engine, walk back to the motor & check the rods for play. So I'll do that. I'll buy a p.r. checker and go that route. Like I said, I have 8.025 in there now, probably a 8 to 9" rod checker should do it? Or should I go larger?
Thanks for the help.

 

[Buick Mark]

8 to 9 inch will work

 

[Hyboost]

Thanks, I ordered one from Summit yesterday, and already got it today. They have the fastest shipping.
Too bad I didn't order it last week, I bought an electric exhaust cutout for $169.00 and the shipping and handling was free for orders over $99.
Oh well, Length checker was only $14, + 4 shipping.

I'll do the work next week, as I'm flying off to Fla tomorrow to hop on the Royal Caribbean ship, "Enchantment Of The Seas" for a cruise to the Bahamas!

Anyone want to come to my house and do the work for me so it's all set when I get home? B/C I'm probably going to be too fat and lazy when
I get home.
No? Didn't think so!

Anyhow, thanks for all the responses and advice. I'm looking forward to a quieter engine.

NTM, I'd guess I'm losing some oil up through the P.R. to the rockers if the pushrod is "losing contact" with the lifter, even a little every time the valves open and close.

As I ran it at idle with the VC's off, there wasn't a ton of oil coming up through the rods, when I reved it up, even a little, it flowed much more but not like a chevy small block. Where oil sprays all over the engine, at anything over idle.

 

[Buick Mark]

Nevermind your vacation, stay home and fix the Buick, THATS more important LOL

 

[Hyboost]

Ha ha, I know, it's going to bug me the whole time I'm gone!!