2024 Canadian Poncho Calendars are Now Available! CLICK HERE

 

 

Members Login
Username 
 
Password 
    Remember Me  
Post Info TOPIC: 400 sbc in LeMans making ticking sound


Member

Status: Offline
Posts: 20
Date:
400 sbc in LeMans making ticking sound


Hey guys, new to the forum I have a engine question. Last summer I bought a 72 Luxury LeMans with a 400 small block chevy from a 74 full size chev. The engine worked fine until this summer when I started driving the car, after taking it out of storage and it developed a ticking sound. I ran sea foam through it figuring it was a sticky lifter, and did a fresh oil change after but noise did not go away. Then I adjusted the lifters to ensure all the back lash was taken out and the ticking is still there. The ticking gets louder when the engine is under load and accelerating. And it will not go away even when the engine is warm. Could this be a header leak? The headers aren't in the best shape they are pretty rusty and I have had to get them welded near  the collector because they burned through. Also the gaskets look in bad shape too and seem to look delaminated. I used a mechanics stethoscope and it seems hat #8 cylinder is making the noise. any help would be appreciated. thanks.



__________________


A Poncho Legend!

Status: Offline
Posts: 20051
Date:

Based on what you have done it seems that exhaust leaks are the next area to investigate. I had a Monza with a small block that ticked like crazy and in the end it was a bad header gasket and loose header bolts. Of course the engine had to be lifted to repair this since the engine was shoehorned in there and the headers were in three pieces.



__________________

Ray White, Toronto ON

1973 LeMans 454 "Astro-Jet"

Built March 9, 1973 - Oshawa ON

1993 Corvette Convertible LT 1

Built January 10, 1993 - Bowling Green Kentucky 

 




Addicted!

Status: Offline
Posts: 257
Date:

  If the noise is from the back of the engine, maybe a cracked flex plate.



__________________


Canadian Poncho Superstar!

Status: Offline
Posts: 4505
Date:

I don't suppose you are running the 74 smog pump or at least the original 74 exhaust manifolds with the smog tubes. Dad had a 74 Biscayne with a 350 that started ticking all the time. We took it to his old-time mechanic Roy, who must have been 70 years old at the time. What sounded to us like a lifter noise ended up being a small perforation in the smog tubes. Roy took off the complete smog setup (I should have kept it...), plugged the holes in the manifolds where the smog tubes went in and, no more ticking!

 

Attached is exactly what a stock 73 or 74 small block Chevy looked like fully dressed and in production form. Our 74 engine looked exactly like this, as would a 400 SBC. Note the tubes about the exhaust manifolds. They were the culprits. If the smog was removed and the holes were epoxied, perhaps the epoxy is blowing out.

7374L65.jpg



Attachments
__________________

67 Chevelle Malibu Sport Coupe, Oshawa-built 250 PG never disturbed.

In garage, 296 cid inline six & TH350...

Cam, Toronto.


I don't judge a man by how far he's fallen, but by how far back he bounces - Patton



Poncho Master!

Status: Offline
Posts: 2656
Date:

Check the header gasket around each cylinder.You should see a bit of black/grey mark (exhaust) in this area.Sometimes the gasket burns through between the cylinders as the Mr.Gasket type get very hard and brittle from heat. I had this problem once and replaced the gaskets with carbon fiber ones from Percy's and no more blown gasket.

__________________


Canadian Poncho Superstar!

Status: Offline
Posts: 5990
Date:

I find the whole smog pump thing very interesting because my original 1974 Chev 400 V-8 small block never came with one. My dad bought the car new ( 74 Chev Caprice Estate wagon ) and the car and motor have never been molested. Cam, why is it some 74 400's had smog pumps and others did not. My 74 Chev was built in Oshawa, could the U.S. built 400's have smog pumps only? Here are some photos of my 74 Chev 400 V8. Cheers. George.



Attachments
__________________

1957 Pontiac Pathfinder Deluxe sedan restored 261 six

1974 Chevrolet Caprice Estate wagon low mileage original 400 V-8



Canadian Poncho Superstar!

Status: Offline
Posts: 4505
Date:

long stroke wrote:

I find the whole smog pump thing very interesting because my original 1974 Chev 400 V-8 small block never came with one. My dad bought the car new ( 74 Chev Caprice Estate wagon ) and the car and motor have never been molested. Cam, why is it some 74 400's had smog pumps and others did not. My 74 Chev was built in Oshawa, could the U.S. built 400's have smog pumps only? Here are some photos of my 74 Chev 400 V8. Cheers. George.


 George, all 1974 Big Chevrolet engines and models came with a smog pump - except the LT4 400 4-barrel. The 400 2-barrel (LF6) was standard in the Caprice Classic series and optional on all others and used the smog pump, however all the wagons used the 400 4-barrel (LT4) exclusively as a standard engine and did not come with a smog pump unless it was a California car.

Incidently in California for 1974 they didn't offer any 2-barrel Chevy V8 engines, only the 4-barrel versions could pass the strict emissions tests (presumably due in part to the small 1.38" primaries vs. the 1.69" venturies of the 2-barrel carbs.) The Quadrajets in California carried different part #s so there were other calibrations as well. Getting stuff emissions-certified for sale was a panic back then, and with California being especially demanding they concentrated on the tweaking the Quadrajet with its smaller 1.38" primaries.

In 49 states plus Canada you got the L65 350-2, LF6 400-2 or the LS4 454-4, plus the LT4 400-4 exclusive to wagons. California got the LM1 350-4, LT4 400-4 and the LS4 454-4. Canada also was unique in that Biscayne, Bel Air & Impala coupes & sedans in Canada offered a 350-4, the LM1 with single exhaust. The Canadian LM1s used a smog pump, as did all California engines. 

The L48 350-4 with dual exhausts on Chevelles & Monte Carlos (plus Canadian Lemans) were exclusive to Canada that year.



-- Edited by CdnGMfan on Friday 27th of June 2014 12:24:43 AM

__________________

67 Chevelle Malibu Sport Coupe, Oshawa-built 250 PG never disturbed.

In garage, 296 cid inline six & TH350...

Cam, Toronto.


I don't judge a man by how far he's fallen, but by how far back he bounces - Patton



A Poncho Legend!

Status: Offline
Posts: 20051
Date:

Cam is bang on on Canadian LeMans, our first 73 with L48 had the set up as shown ion the photo. By trade in time in 76 it was starting to leak, tick and hiss. The car I have now had the tubes brazed closed on one side and still had the piping on the other albeit leaking and ticking when I git it in 2004. The AIR brackets and pulleys were in the trunk in a box. 



__________________

Ray White, Toronto ON

1973 LeMans 454 "Astro-Jet"

Built March 9, 1973 - Oshawa ON

1993 Corvette Convertible LT 1

Built January 10, 1993 - Bowling Green Kentucky 

 




Canadian Poncho Superstar!

Status: Offline
Posts: 5990
Date:

Cam, thank you for all the clarification on the 400 Chev V-8 and smog pumps. My wagon certainly is a four barrel 400 and i am very thankful it never came with that silly smog pump. I look at a smog pump as just another device to maintain, another device to break down and another device to cost you money. Plus it puts more drag on the motor and look at that.............. it leaks exhaust too. I will admit though, it is neat to look at on an engine. Cheers. George.



__________________

1957 Pontiac Pathfinder Deluxe sedan restored 261 six

1974 Chevrolet Caprice Estate wagon low mileage original 400 V-8

Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.

Tweet this page Post to Digg Post to Del.icio.us
.
Support Canadian Poncho!
Select Amount:
<
.
.
.