TTEC4842 - Automotive Engines cylinder head

TTEC4842 - Automotive Engines -  practical

02/11/2011 wednesday

start = 1.00pm finsh = 4.30pm

( engine cylinder head )

first thing i did was take the cylinder head into parts from camshaft, vavles,timing belt,water pump Etc.

Inspection of cylinder head

first thing i did was visual check on the cylinder head check for any cracks sign on burning or any scuffing, broken edges,threads,corrosion,Etc

Then i used precision straight edge and feeler gauge. to measure the head face surface for warpage.

maximum warp specification		actul warp	pass	fail
0.15mm	across	0.1mm	ok
0.15mm	length	0.0mm	ok
0.15mm	diagonal	0.0mm	ok

The cylinder head i was working on was in good condition no sign of warp and it meet the specification. if the block was bend or anything it needs to be replaced there wont be no use for it.

checking valve guide clearance by measurment

	cylinder 1		cylinder 2			cylinder 3		cylinder 4
position a	5.98mm	5.98mm		5.99mm	5.97mm	5.99mm	5.99mm	5.98mm	5.99mm
position b	5.99mm	5.97mm		5.98mm	5.98mm	5.98mm	5.97mm	5.99mm	5.97mm
position c	5.98mm	5.96mm		5.96mm	5.99mm	5.98mm	5.98mm	5.99mm	5.98mm
	IN	EX		IN	EX	IN	EX	IN	EX
average reading	5.983mm	5.97mm		5.97mm	5.97mm	5.98mm	5.97mm	5.98mm	5.98mm

i checked for valve clearance which was A is from the top B from the middle and C from the bottom. my valve clearance meet the specification which was 6.01-6.03mm , by getting the average reading which i did A+B+C/3 to get the average reading.

Valve Stem measurerment

	cylinder 1		cylinder 2			cylinder 3		cylinder 4
position A	5.95mm	5.95mm		5.95mm	5.95mm	5.95mm	5.95mm	5.95mm	5.96mm
position B	5.96mm	5.96mm		5.96mm	5.96mm	5.96mm	5.96mm	5.96mm	5.97mm
position C	5.96mm	5.98mm		5.97mm	5.98mm	5.98mm	5.97mm	5.98mm	5.99mm
	IN	EX		IN	EX	IN	EX	IN	EX
average reading	5.96mm	5.96mm		5.95mm	5.96mm	5.96mm	5.95mm	5.96mm	5.97mm

I checked for the valves stem, and the all meet the specification which was IN= 5.970-5.985mm EX=5.965-5.980 by getting the average reading is by A+B+C/3 this showed me that the valves are in good condition and no replacing required.

check valve condition

first thing was i did check the valves conditions see if there is any damage on the lips, wear in the collet grooves, signs of any scuffing, any sign of cracks Etc

Then i moved on checking the valve margin.

cylinder 1	inlet-valve		Exhaust valve
valve margin	1.0mm	ok	1.0mm	ok
cylinder 2	inlet-valve		exhaust valve
valve margin	1.0mm	ok	1.0mm	ok
cylinder 3	inlet-valve		exhaust valve
valve margine	1.0mm	ok	1.0mm	ok
cylinder 4	inlet-valve		exhaust valve
valve margin	1.0mm	ok	1.0mm	ok

I checked the valve margin and they were all in good condition theres no replacing required.

Valve seats- gernal condition and serviceability

First thing i did was a visual inspection on the valves seats . check the seat width , seal angle, surface finsh , thikness of remaining material.

Refacing valves and valves seats.

The valves were in good condition suitable to be refitted without further work.

Inspection of valve springs

First thing i did was check valve spring is square. by using a surface plate and an engineers set square to check squareness of valve spring.

1. = .406mm  ok
2. = .457mm  ok
3. = .408mm  ok
4. = .447mm  ok
5. = .456mm ok
6.= .457mm  ok
7. = .458mm  ok
8. = .457mm ok

The springs were all in specifications which was 1.6mm that means they are good to re use.

Inspection of valve springs

checking free length

checking for all springs in a set should have a free length within 1.5mm of each other.

       Inler         exhaust
1.= 47.1mm     46.3mm ok
2. = 46.2mm    46.3mm  ok
3. = 46.4mm    47.3mm  ok
4. = 46.5mm     46.1mm  ok
5. = 46.2mm     46.2mm  ok
6. = 46.2mm     46.1mm  ok
7. = 46.1mm      46.1mm ok
8. = 46.5mm     46.1mm  ok

They were all with the specifications. which was 47.2mm that showed me the springs are in good conditions.

Inspection of valve spring tension

first thing was is to check the spring tension is by using a pressure tester to test the springs.

1. = 14.1kg  fail
2. = 15.7kg  fail
3. = 14.2kg  fail
4. = 15.0kg  fail
5. = 14.7kg fail
6. = 14.2kg  fail
7. = 14.7kg  fail
8. = 14.7kg  fail

These spring failed to meet the specification which was 20kg to get them to 20kg was to put 5 seals under them which its not good the best option is by replacing them with better once.

Inspecting Camshaft for wear and general condition

Measure camshaft lobes and calculate the lift of each lobe.

cylinder 1

Inlet A) 40.73mm B) 32.87  (lift) 7.86mm      Exhaust A) 40.82  B) 32.85  (lift) 7.97mm

Cylinder 2

Inlet A) 40.60mm B) 32.56  (lift) 8.04mm      Exhaust A) 40.88  B) 32.60  (lift) 8.28mm

Cylinder 3

Inlet A) 40.94mm B) 32.87  (lift) 8.07mm      Exhaust A) 40.70  B) 32.80  (lift) 7.90mm

Cylinder 4

Inlet A) 40.70mm B) 32.90  (lift) 7.80mm      Exhaust A) 40.89  B) 32.85  (lift) 8.04mm

This showed that the inlet and the Exhaust cam lobes didnt have the same amount of fit. But the camshaft serviceable and yes its in good condition.

Measure Camshaft Bearing journals for wear using External micrometer.

For this task i will be measuring for both taper and ovality.

Inlet- Exhaust
by working out the ovality i minused A from B, and to get Taper i minused  1 from 2.
The journals meet the specification which was 0.05 the camshaft bearing journals were in good condition

Measure Camshaft Run-Out.

I measured the camshaft run out by puting it on a 'v' stand to measure the run out.
For INLET = 0.02  EXHAUST = 0.01
both camshaft meet the specification which was 0.03 this showed that the camshaft is in good condition.

Checking camshaft bearing oil clearance ( using plastigauge)

Oil clearnace

	Front	Middle		Rear
	1	2	3	4
Journal Ovality	IN .02EX	IN .02EX .00	IN .01 EX .01	IN .00 EX .01
Journal Taper	IN .01 Ex .00	IN .01 EX .00	IN .00 EX .00	IN .00 EX .00
	ok	ok	ok	ok

run out using 'v' and a dial test Indicator 

I measured the camshaft run out for INLET 0.02 and for EXHAUST 0.01 both camshaft were in the specification  which is 0.03 and were in good condition.

Checking camshaft Bearing oil clearancen ( using plasti - gauge

Oil clearance

	Journal 1	2	3	4	5
oil clearance	0.076	0.025	0.038	0.038	0.038

 by checking the oil clearance with a plasti gauge this showed that they meet the specification which was 0.035 - 0.081mm

Measure camshaft end play

I measured the cmashaft end play using a loyometer . i measured the end play for INLET 0.01mm and EXHAUST 0.01 Both were in the specification which was 0.07 - 0.19mm

conclusion

The cylinder head i was working on was in good condition and meet all the specification which is good. there was no sign of damage or and bending on it. the block is in good condition and its serviceable for road use again